# Crossovers - where to start?



## Odougbo

Hey all & Happy New Year!

In the pic is a TB W5-1611SAF, full range; however the high end is very week. 

Getting good robust sound, bass/mid and would like to add tweeter to brighten them up. 

The TB woofer is 8ohm-90db and have some MDT-28s, 8ohm-91db. (could order new tweeters)

I see there a host of on line calculators - this one almost seems to easy: 

http://www.diyaudioandvideo.com/Calculator/XOver/

Never had much luck with xo design, but lots of caps/coils here - where to start? 

I'm assuming the TB is going to need a 12db slope, since it's a full range.

Thanks in advance for any advise!


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## robbo266317

They are a close match in sensitivity. Do you have the specs for the 28s. I looked online but could not find them.


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## Odougbo

Sorry no specs on the Morel - I did look from them also...nada.

Which is hard to believe, must be a million of them out there.

Thanks


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## Odougbo

No luck on the Morel (again). 

I'd order a new set - PE has 100+ tweeters:
http://www.parts-express.com/cat/tweeters/17

Where would be a good xo point to start? 4,000?




Odougbo said:


> Sorry no specs on the Morel - I did look from them also...nada.
> 
> Which is hard to believe, must be a million of them out there.
> 
> Thanks


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## robbo266317

Since the other driver is full range then that would be reasonable, along with the fact that the 29 has a stated response of Frequency response: 1,800-20,000 Hz. So you could, theoretically, use a first order crossover at 3,600 Hz.

Assuming (rightly or wrongly) that the 28s has similar specs then a second or third order crossover at 4kHz would fit nicely.


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## Odougbo

Thinking out loud here - I do have a pair of Vifa's that I never used.

D27TG-05-06 Specs are easy to find:
http://www.parts-express.com/pdf/264-524.pdf


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## robbo266317

They should be good also. 
Looking at their graph you could cross them at 2.5kHz and above with any order crossover.
Again 4kHz is fine.


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## Odougbo

The vifa tweeter (link) has a 6 component xo - is Fc[HZ] the xo - 3,500hz?


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## Odougbo

I did piece together a xo - it's a little scary :gulp:

I used the tweeter xo from the PDF for the vifa tweeter.

The woofer I tried different coils/caps using the 2nd order Butterwoth 2200hz.

I think the tweeter is a bit "louder" than woofer,,,btw.


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## Odougbo

update:

Added 4R @ Vifa tweeter (whew) The tweeter is a bit harsh, but better with attenuation.

The xo point is 2200 - easy to hear that.

They are sounding okay...some imaging. 

I guess I could upgrade the parts, e.g. using small iron core bobbin(s) for tweeter.


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## robbo266317

I'm going out for a bush walk this morning. 
I will check your values if you like when I get back.

Cheers,
Bill.


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## SirKevi

I found this out about your Morel mdt 28 tweeters. Apparently from the guy that designed them.

At this point, we decided not to sell the cabinet systems for the time being and instead began developing high quality raw drivers. About a year later my staff and I came out with our first driver design called the ‘MDT-28’ tweeter. It still is our best selling tweeter. I took this design to Meir in Israel and told him this was the tweeter we needed to sell. We decided to produce it. Now it is called the ‘MDT-30’ and ‘MDT-30s’ (these are basically the same tweeter). Around the same time, Meir, changed the cosmetics of the Dynaudio 8” woofer and Dynaudio tweeter and made them under the Morel names ‘222-D’ and ‘MDT-27’. As time passed, Meir and I developed many other drivers.

This would be the specs on your tweeters http://www.morelhifi.com/old/products/pdf/mdt 30s.pdf.
Even if you dont use these in this project it could be handy for another project.


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## robbo266317

It seems your values are not quite right and the attenuation for the tweeter needs to be done closer to the driver itself so it doesn't affect the total impedance of the system. 

For a 2.2kHz crossover you need the following circuit followed by an L Pad to drop the level to match the full-range driver. (I have used 1dB as an example, you may need more.)

R1 and R2 are calculated in the second diagram.

Also remember to reverse the polarity of the tweeter as a second order butterworth causes a 180° phase shift at the crossover point.


















These tools are available here: http://www.apicsllc.com/apics/Misc/filter2.html


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## Odougbo

moo cow! I went to the Morel site also, I thought I would have to send a email (and never hear back).

I've heard that the 28 and 30s are the same, the plate is .5mm thicker on the MDT-30. 

I don't know about the Vifa tweeter...never found a place for it (never tried this hard either). It has a knee bend slope, the tweeter is off and running at 2,500hz.


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## Odougbo

Aye Crumba..I needed to reverse the tweeter leads??? - I all most knew that. :rant:

I'll try the morel tweeter with this xo. 

The woofer coil is .9, 18 gauge (now) using, lost some of the robust bass, I'll look for thicker wire coils and go with the 8.1mH / 6uF cap.


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## robbo266317

Odougbo said:


> Aye Crumba..I needed to reverse the tweeter leads??? - I all most knew that. :rant:
> 
> I'll try the morel tweeter with this xo.
> 
> The woofer coil is .9, 18 gauge (now) using, lost some of the robust bass, I'll look for thicker wire coils and go with the 8.1mH / 6uF cap.


:rofl: I have done that in the past, as well as a few others....

The inductor is 0.8 mH and the lower the resistance the better. 

With Butterworth crossovers the odd ones - 1st, 3rd ,5th etc are in phase.
The even ones 2nd, 4th etc are out of phase.


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## Odougbo

Found some Erse 14gage, almost .8 (7.9mh)

btw, here's a pic of the ports-on-side.

[this is a different box]

I'm having a blast with these, the flares enhances the low end a bit. Can only do this with Gen, while in fabrication - i.e. trim down as needed.


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## robbo266317

Did you do the flare or is it machine done?


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## Odougbo

Odougbo is Jedi Master of tuning semi built boxes.
It works - it's fun!! 


Nothing fancy here - Jig saw.

I cut the flares much closer together and then trimmed the back edge.

Clamped it all together: 4 flares and both sides & check tuning.

repeat as necessary

I think its tunned to 60hz, don't remember, whatever WinIsd came up with.


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## robbo266317

You certainly have done a good job on it.
I gave up on using a jigsaw, except to create templates that I then finish with files and a router.


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## Odougbo

I cut them best I could - stacked them in vice and belt sanded the sides of them.

prototypes take forever......but whats the rush anywaylddude:


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## robbo266317

I know what you mean, my belt sander weighs over 1kg and really is tedious to use that way.
These days I make one thin, ie 8 - 10 mm, mdf template and then use a router with a straight edge bit with ball bearing wheel to shape the rest.


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## Odougbo

Ohhhh you're going to need one of these then!

Best router bit for speakers builders - top and bottom bearings!

http://www.amanatool.com/routerbits/down-shear-trimmer-47094.html


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## Odougbo

Moo Cow  

Hey not bad...... The bass is back. I like the sound of the reverse tweeter.

The Morels are smother, still getting a bit of a shout now and then.

New to move them a room with some carpet. 

I guess I could go back and slip in a 15w L-pad, while I wait for some extra parts.


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## Odougbo

Now I did use my router the other day.

Extra bonus points if you can tell me what is inside the bases? :dontknow:





robbo266317 said:


> I know what you mean, my belt sander weighs over 1kg and really is tedious to use that way.
> These days I make one thin, ie 8 - 10 mm, mdf template and then use a router with a straight edge bit with ball bearing wheel to shape the rest.
> 
> View attachment 39653


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## robbo266317

Bees, I'm guessing it's Bees....


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## Odougbo

Bees? :yikes:

When you have wood - thats what you use.


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## robbo266317

Very nice! 

Not much room for the honeycomb though! :scratch:


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## Odougbo

Where to start...maybe with new glasses :rubeyes: I put a 9R instead of .9 in the L-pad.

I'm on it!!!


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## Odougbo

Okay better - I even made sure the tweeter coil & woofer coil are the same (8.3ohm)
Tweeter 18g/Woofer 14g 

The woofer is not going down without a fight - which I expected. I.e. it is competing with the Tweeter above 2200hz. (4,000 I can't hear the woofer at all)

I could order new tweeters...just so many out there. Maybe one closer to 89db - 90db.


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## robbo266317

Odougbo said:


> The woofer is not going down without a fight - which I expected. I.e. it is competing with the Tweeter above 2200hz. (4,000 I can't hear the woofer at all)
> 
> I could order new tweeters...just so many out there. Maybe one closer to 89db - 90db.


Do you have access to a SPL meter or REW?

REW makes it easy to measure the difference in levels between the two drivers, then just calculate the value needed for the L Pad circuit.


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## Odougbo

Lent my SPL to a buddy - few years later he showed me his meter :yikes:

Friends NEVER LEND TOOLS - NEVER LEND TOOLS WITHOUT YOUR NAME...:nono:

I'm sure I can pad the tweeter down, this is not Odougbo's first rodeo :rofl:

I think - - - I need help with xo point and/or phase issues. 

The Morel are known for mid range, it has 1,500 printed right on the back. I wouldn't mind trying something new.


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## Odougbo

:help:


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## robbo266317

That looks pretty good frequency wise.

It looks like it is tuned to 65 Hz. The rise in impedance at that point is typical for a tuned enclosure.
You could add a Zobel network to reduce the impedance at the top end although it is not excessive.


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## Odougbo

I checked the woofer xo with clip lead (shunt) it does seem to work around 2,000+ :boxer:

The one morel had a buzz (which is not uncommon) - I had one left, that was clearer.


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## Odougbo

Cool inside Pic


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## Odougbo

There's some kind of overlap problem - the tweeter might just be going too low. In desperation I used a 6db L-pad which sounded best of all - but cymbals are starting to fade away.

I.e. the mid range is way too  However the bass is really kicking!!!!

Trial & Error - maybe switch to bigger coil (1mH) and/or smaller cap.


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## robbo266317

The butterworth design has a slight rise at the crossover point. This could be causing your issues. 
(Again, access to REW would confirm this. You could replace each speaker with an 8Ω resistor and then combine the two graphs.)

Alternatively, If you have the resources, a Linkwitz-Riley configuration is flat across the crossover region. 

eg


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## Odougbo

Aye - just what I envisioned 4.uF and 1.15mH (x2)

This has been a lot of work but a good learning exercise. :run2::run:

This is much better...whew.


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## Odougbo

Removed.


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## Odougbo

I had a pair of Clarity Caps (large size, Red color) 3.9uf so slipped them in (removed the 4.7 tweeter cap). 

That was a large improvement, a much sweeter sound. I don't know, some say caps don't make a difference but some swear by them.

E.g. SR71s use them.


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## Odougbo

New idea - going to move xo point way up.

Going to use xo design from here and use Vifa X25s

http://www.troelsgravesen.dk/VifaPL14WJ+XT25TG.htm

New pic


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## Odougbo

This is working well (not much to look at) well balanced, light/delicate, with great bass.


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## robbo266317

It's good when you get a system that works well. 
Although, it's the ultimate never ending story.... :devil:


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## Odougbo

The smartest thing I did yesterday was to add small terminal bock for the 1st tweeter resisitor - now it only takes a few seconds to try different values and levels.

Settled on 3.3ohm. 

I should mention, when I 1st looked at the xo circuitry I was :huh: but it's not bad at all (and why started this project)


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## Odougbo

Another front flare project, 2 days to get box tuning right, 3 day total.

Drivers: 6.5 Silver Fute / Vifa X25 in a 13 liter box, tuned to 50hz.

I have a few ides for a xo (my Achilles' heal). Getting some rice sound using xo that I've been using for another project, sounds good, not perfect, but need to break in speakers anyway.

I'm going to give Madisound a buzz, they have these drivers so they can provide a xo design, $30 I think.


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## Odougbo

One more pic and thanks to the Moderator!

The "vents" are 1/2" MDF. I was in laa-land thinking to cut them all at once.

I made up a simple pattern and cut them one at a time (screw holes are not an issue so a little easier)

Pushing these boxes, gesh they have really big bold, box sound!!


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## Odougbo

Back to the beginning - used a new xo for the Silver Flute project - used a muti part xo for the X25 tweeter (never sounded better) - and a filter supplied by Madisound for the woofer.

Which is same as xo design chart 1.8 coil - 7uf cap. 

I did place an order for a full LEAP design.


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## robbo266317

You should have a nice set of speakers when you finalise the setup.

What subwoofer are you going to use with them? :devil:


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## Odougbo

Not going to give in without trying several xo's! My buddy can measure, but I get a headache if speakers don't sound right :coocoo:

Getting good amount of bass now, but have 5 of these (PIC Below) in different combinations, i.e. folded and single fold TTQWT (sub woofers) The single folds' are 9" wide.


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## Odougbo

The xo work is going well, the compact speakers have some great bass (unexpected). 
Question about the zoble, it is asking for Inductive Equivalent (Le) Henries :dontknow:

I toggled in a few numbers and get crazy cap sizes - Do I go back to spec sheet? 

Le @ 1kHz 0.94 mH (cap 17,639 uf)


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## Odougbo

Too much fun :R

3 more - can try in the 5.1 (as soon as finished)


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## Odougbo

A lot of speaker for $30 woofer and $32 tweeter.

:unbelievable:

Could be :coocoo: but thinking the W design box attenuates standing waves, the box is a "black hole" - I.e. no echo.


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## robbo266317

Odougbo said:


> The xo work is going well, the compact speakers have some great bass (unexpected).
> Question about the zoble, it is asking for Inductive Equivalent (Le) Henries :dontknow:
> 
> I toggled in a few numbers and get crazy cap sizes - Do I go back to spec sheet?
> 
> Le @ 1kHz 0.94 mH (cap 17,639 uf)


It's in the conversion factor. Henries vs milli-Henries
How does 11µF and 9 Ω sound.

http://diyaudioprojects.com/Technical/Speaker-Zobel/


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## Odougbo

Thanks Rob - now that calculator seems to work and makes sense - got some crazy values with the other :wits-end:

I have something that seemes to work while waiting for parts: 3.3R and 12uf cap.

There's a sizzle sound in the very high end of the woofer, the 3.3/12uf cap zaps it out.

Whats a draw back of a zobel? (there's always a catch), I thought I started to hear that tin-can-sound with some of the other combinations.


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## robbo266317

The Zobel network is purely to make the amplifier and crossover see a fixed load across the frequency range.


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## Odougbo

Thanks Rob,

Buddy came over yesterday; quite versed in xo design/measuring. He helped with many of the elementary questions. :duh:

We found that both drivers have a slight breakup at xo point, the tweeter is out-of-phase to cancel that out (guessing, but seems to work).

So close but yet so far....:blink:

New xo by Madisound here in day or two


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## Odougbo

New xo on it's way! :woohoo:


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## Odougbo

Madisound sound moves fast! New xo's, in just a couple of days, and they included "cut sheet" with order; very professional!

This is working nice, but I guess it never ends, going to try two other types of woofer coils:

15 gauge steel lam
12 gauge air


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## robbo266317

That's a neat board.

It looks like it is designed to do multiple styles of crossover.


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## Odougbo

They were sounding nice with the 16g series woofer coil, but needed a tad more bass - although would be fine for HT as is.

[if fact I think the smaller inductor would be better for HT so the low bass doesn't compete with a HT sub-woofer]

I really wanted to hear some bass extension without subwoofer; so shortened a few wires, used 14g feed wire and swapped the woofer coil to the 14g - amazing improvement!! The woofers have about 40 hours on them; I suspect they will loosen up over time and get even stronger.

btw...Kudos to Madisound they designed the xo, and sending parts in record time (e.g. 3 small orders in 1 week).


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## Odougbo

Some additional feedback (3 are finished)

* one pair in "stereo" room - crazy low bass, very nice definition with bass and guitar strings, vocals are natural and smooth. I did change the 1st series tweeter from 2.2ohm to 3.3ohm; the tweeter was a little hot on some songs. Also as mentioned swapped the series woofer coil to 14 gauge

* HT center channel- ordered just enough parts to complete the 3rd - shown left/down. Again, rich bass, set xo in processor to 40, which was too low, then moved to 80hz. :T

I like that the tweeter resistor can be switched for tweaking; this is not something that can be done in 5 minutes, need to sit and listen for a while, try many sources, songs movies, etc. (re-soldering is only 5 minutes).


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## Odougbo

Now my friends are calling these the Penguins.

I tell them they kick like a Kangaroo...........:rofl:


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## robbo266317

Actually, to me, they look more like the Portal Turrets. :rofl2:


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## Odougbo

The bass on them is remarkable. I'm tempted to add a subwoofer, but fine without one. 

(They are are stands and about 8" from wall)

btw, posting the MS crossover. As you can see, I thought the tweeter was was a bit hot, so jumped to slightly larger resistor. 

http://www.madisoundspeakerstore.co...-6-7/silver-flute-w17rc38-08-6-1/2-wool-cone/

http://www.madisoundspeakerstore.co...ers/vifa-xt25tg30-04-1-ring-radiator-tweeter/

MS is out-of-stock on tweeters, PE still has them.



What are Portal Sentry Turrets? From a Syfy move?


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## robbo266317

It is a video game, very popular when it came out and followed up with Portal 2.
The turret can be seen at 1:05 in the demo clip here:


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## Odougbo

Now here is a low resistance coil :unbelievable:

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=255-804&scqty=2


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## ISLAND1000

What IS the resistance of that EXPENSIVE coil?


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## robbo266317

The one they show in the picture is 3.3mH - 0.07Ω









It's not that expensive considering the copper for my four air core, self wound 1.3 mH coils in 1986 cost me au$50.00 (about two days wages) and their impedance was 0.7Ω


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## Odougbo

I guess they only have the stock pic - 3.3mh looks like 20' (3 meters) of wire I bet a 1.5mh is 2/3 of what is shown.

They were for high power application - so I didn't get them, but did spurge on 14gauge foil, which was $1 - $2 less.

Loving these little speakers; my speaker grue-guy said a lot of the manufactures are using this design of a isolated tweeters...great minds I guess :rofl:

Naaa...I saw a pic of a baffle cut like this long ago, things like this I can remember :nerd:


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## Odougbo

The blue ones were made 20+ years ago - ordered 1 factory coil to see what I could improve - which is obvious now (way to tall) Going to make new, thinner pexi spools and re-wind them.


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## ISLAND1000

I have a tweeter with a resonant chamber and a port in the back. Tang Band 28-537SH doesn't have any suggestions for mounting either interior or exterior.
I'm going to try inside on front baffle first, then outside on a bracket.
I'm curious if the tweeters rear port would allow the woofer to over drive the tweeter cone.


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## robbo266317

ISLAND1000 said:


> I have a tweeter with a resonant chamber and a port in the back. Tang Band 28-537SH doesn't have any suggestions for mounting either interior or exterior.
> I'm going to try inside on front baffle first, then outside on a bracket.
> I'm curious if the tweeters rear port would allow the woofer to over drive the tweeter cone.


I would definitely consider it's own enclosure. 
Have you done a search on the driver to see any recommendations?


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## Odougbo

That looks like a nice tweeter:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-870 I have some old Morels with the same features. They are wonderful, except they just don't go up high enough (Morels).

I need to make some tweeter bullet shaped inclosures (I gave my tweeter brackets to a friend), I'll need to mount with a dowel or metal post.

Up to 8 boxes now, but only using two next to TV. The wife and I are :unbelievable: :unbelievable: 

Great Bass :hsd: super highs and haven't missed a word in a movie yet. The lower register in voices is also simply amazing. 

It doesn't all add up with the low cost drivers, but there is extra work with the cork and felt lining, 1"backs, triple layer sides and the flares are apparently all working in harmony . 

[I'm getting faster at building them, prototyping is a lot of work, lot easier with a recipe]


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## ISLAND1000

robbo266317 said:


> Have you done a search on the driver to see any recommendations?


`
There's nothing here on Home Theater Shack and I haven't found anything of value anywhere else.


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## Odougbo

This is the one people rave about.......

http://www.madisoundspeakerstore.co...=search&search_in=name&search_str=hds+tweeter

I think they double the price on the speakers that work better than the rest of the pack - I say FOUL BALL!! :hissyfit:


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## Odougbo

Been hanging on to a pair of 6.0mh coils, but sacrificed for this project. Which was good, made up two 1.5mh out of the larger 6.0mh coil; and only a 6' piece left over.

btw.....the meter was only $35, ~ that's the cost of one coil.


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## ISLAND1000

Odougbo said:


> This is the one people rave about.......
> 
> http://www.madisoundspeakerstore.co...=search&search_in=name&search_str=hds+tweeter
> 
> I think they double the price on the speakers that work better than the rest of the pack - I say FOUL BALL!! :hissyfit:


You make a valid "audio consumer" point.
Especially "Tweeters" how do we (the consumer) tell which one is the BEST? . . . . or better? With a woofer, us guys can tell. If a woofer can flap our pants legs, it's good. If a woofer can give us that "kick in the chest feeling" that's good. If a woofer can rattle my wife's fine china in the next room, that's good. If you can see the woofer cone gyrating in and out a full inch, that's good. If your neighbor calls the cops twice a week cause he can hear, feel, and have his wife's fine china rattled, that too would be a good woofer. But what about Tweeters??? Have you ever heard of a tweeter that could kick you in the chest?
OK, you say, test them by listening to them. OK, what do we listen for? You say, flat frequency response, little distortion, and non fatiguing. But, aren't those qualities best measured by machines ie: meters, scopes, and graphs? And if that's so, when we wanna go out and BUY a tweeter, what IS IT that's going to tell US how they sound and perform? Usually the tweeters are combined in a system with other drivers. They are combined with a minimum of one other driver, a woofer. You know, a woofer and a tweeter. That's the classical 2-way system. Even in a simple 2-way system, how do you separate the two drivers and their respective auditory performance from each other? Which is producing that ugly distortion, the woofer or the tweeter?
OK, so lets not judge a Tweeter in situ, what OTHER way does the consumer have to judge a tweeter? I know, listen to the tweeter without any other driver present and operating . . . . right? Have you ever listened to just a tweeter with nothing else running? They sound terrible! Add to that, that virtually ALL tweeters must have a cross-over circuit attached to protect it from low Hz material and to separate the high frequencies from the lows at some point in both drivers ability to reproduce sound within their respective (optimum) range with the least amount of distortion of all kinds.
So if we DIYers can't listen to a tweeter and know that, it's the best or, it's better than most, or it has been reported to be one of the best, and there's NO WAY we have the equipment to do any testing ourselves, what are we supposed to do?
I know what I've done. I bought the tweeters after having read the manufacturers claims, looked at the specification sheet/s, studied the frequency response graphs, and compared the distortion figures against other tweeters. Then I designed a 2-way or 3-way system using that particular tweeter, designed a x-over circuit, built a set of enclosures, and finally gave it a listen. Only THEN was I able to tell whether I had the right tweeter or just a high priced metal doughnut. Maybe just maybe the manufacturer had fudged the tweeters performance. Would they really DO something like that? NAAAAWWWWW! LOL
How do YOU guys do it?
In Odougbo's mind, he's thinking "this is the one people rave about". Who's raving? Is that a valid test procedure? Maybe it IS valid taking into account our alternatives. . lddude:


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## robbo266317

They are all valid points Phil.
Now cast your mind back before we had all this information available online...... It was a real minefield. lddude:
Thankfully we can now find reviews and opinions relatively easily to allow us to narrow down the choice of what _may_ work in our design.


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## Odougbo

Well yes and thanks to the forum and all the folks that pipe in with info and police outlandish claims!!

Too many choices.....which can be good and bad :sweat:

Can always "take a poll" on a speaker driver selection; three big companies that you can just call and ask a handful of concerns/questions; before you buy:

http://madisound.com/
http://www.parts-express.com/
http://meniscusaudio.com/

I've called them all, they all have been very helpful and full of great ideas :sn:


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## Odougbo

Looks like there is a "back" - http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-870

But no photo of the back so we can't tell; can always make up a little wood box and glue to inside - I known some DIY guys use small "tin cans" as a chamber.







ISLAND1000 said:


> `
> There's nothing here on Home Theater Shack and I haven't found anything of value anywhere else.


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## georgeallen

realy great information by this thread.


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## ISLAND1000

Odougbo said:


> Looks like there is a "back" - http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-870
> But no photo of the back so we can't tell; can always make up a little wood box and glue to inside - I known some DIY guys use small "tin cans" as a chamber.


I'll try to post a picture of the "port" in the rear of the Tang Band Tweeter. It's teensy compared to the "Holes" in the magnet of a 18" subwoofer. 
I'm wondering if the "port" requires some enclosure beyond the resonant chamber which is already designed into the rear cover. I haven't done any analysis using WinISD. Can you even model a tweeter in WinISD?
On an unrelated subject, what about "baffle step compensation". What about edge diffraction?
Who has those answers?onder:onder:


----------



## robbo266317

ISLAND1000 said:


> I'll try to post a picture of the "port" in the rear of the Tang Band Tweeter. It's teensy compared to the "Holes" in the magnet of a 18" subwoofer.
> I'm wondering if the "port" requires some enclosure beyond the resonant chamber which is already designed into the rear cover. I haven't done any analysis using WinISD. Can you even model a tweeter in WinISD?
> On an unrelated subject, what about "baffle step compensation". What about edge diffraction?
> Who has those answers?onder:onder:


Baffle step is more for the frequencies and distances involved for a midrange driver.


----------



## ISLAND1000

robbo266317 said:


> Baffle step is more for the frequencies and distances involved for a midrange driver.


There's quite a wide ranging discussion about baffle step compensation. Some insist you gotta have it, others say you can compensate using other means, most acknowledge a condition exists that MAY influence the audio product. I'm still unsettled.


----------



## Odougbo

I'm sure BSC is needed on some speaker projects - however one more reason to build "satellite boxes".

The imaging on this last pair of SF/Vifa speakers is outstanding (no BSC) also the TB speaker on the first post is also 5 out of 5 stars. I need to measure the TB pair, like to see the response since I did use the xo from another-similar build.

SF/Vifa build....I asked MS to quote a kit price for woofers/tweeters/prebuilt xo with upgrade parts (Clarity Cap and 14 awg wire) $250 per pair. 

That's about a $100 less than the SR71 speaker kit:

http://www.madisoundspeakerstore.com/2-way-speaker-kits/zaph|audio-sr71-kit-pair-parts-only/

I had a pair of SR71's...okay I guess, I didn't have them long to appreciate them.


Good read: http://news.cnet.com/8301-13645_3-20113895-47/can-sound-quality-be-measured/?tag=cnetRiver


----------



## ISLAND1000

The article you reference is where I'm at. However, it's those pesky engineers that, over time, have brought us to this point of audio nirvana. The overall engineering and technology movement in audio/video technology has obviously been in the right direction. 
Us DIYers have a place in the scheme of things though too. Without US there would have been no search for a speaker capable of reproducing 10Hz @ 110db. There would also NOT be audio crossover capacitors the size of Campbell Soup cans costing $899.00 each! There would be no 1000 watt amplifiers that weigh only 7lbs. So . . . . . never feel like your OWN projects aren't worthy of a deep discussion with others here on Home theater Shack.


----------



## ISLAND1000

Odougbo said:


> The imaging on this last pair of SF/Vifa speakers is outstanding (no BSC) also the TB speaker on the first post is also 5 out of 5 stars. I need to measure the TB pair, like to see the response since I did use the xo from another-similar build.
> 
> SF/Vifa build....I asked MS to quote a kit price for woofers/tweeters/prebuilt xo with upgrade parts (Clarity Cap and 14 awg wire) $250 per pair.
> 
> That's about a $100 less than the SR71 speaker kit:


Which SF/Vifa build are you referencing?

I'm using the same tweeter as used in the SR-71s (Seas 27TDFC) in my current 2 ways with a Peerless 6.5 inch 830874 woofer. That tweeter IS excellent. 
Comparing the two tweeters, the Tang Band TW 28-537SH vs the Seas 27TDFC, 
The Tang Band is much more robust, better build quality, and $20 bucks cheaper. Subjectively, the two have similar audio performance characteristics with a slight edge going to the Tang Band because of lower harmonic distortion. The distortion issue I haven't had a clear chance to evaluate. I'm still in the build stage.
I think one of the reasons the Tang Band tweeter is not more popular is the fact that the performance data lists the "RATED POWER INPUT" at only 12 watts and the "MAXIMUM POWER INPUT" as 100 watts.
A 12 watt tweeter is NOT what any of us are interested in, even with a 4th order X-OVER in place to protect it. The 100 watt "MAXIMUM POWER INPUT" is confusing. Just exactly what does that mean? It's not the usual language used to describe a drivers power capability.
Anyway that's the first thing I checked when I received the Tang band tweeters. I hooked a tweeter up with a 3.9 μF capacitor and began to play music while increasing the volume little by little until my ears hurt.
The fact that it played at what I assumed was at least 95db was proof enough to me that the tweeter had enough power capability to play at volumes loud enough for my average listening environment without damage.


----------



## Odougbo

SF/Vifa?

Silver Flute - Vifa Tweeter - Why that's the Penguin build.


----------



## ISLAND1000

I got it now.


----------



## Odougbo

The thread jumps around a bit, scroll back to post #52.

If you like the sound of a "small 2-way" these are really working well.

Big Bold sound!!!


----------



## ISLAND1000

I've got a bunch of two ways and some 3 ways. I've been experimenting for years.
I'm always looking for new driver combinations and my current duo, Beyma/Tang Band, looks the best so far . . . . on paper.
I've decided lately I need to play louder, don't know why except one of my buddies came to visit and wasn't impressed by my mains. He thought they should play louder. I measured them at 102db at + 6 on the receiver. they were beginning to stress at that volume. That speaker has a 6.5" woofer and a Seas tweeter.
So now I'm working with the Beyma 10" and the Tang Band Tweeter. The Beyma is louder than the 6.5 woofer in free air. The Beyma "sound" is very pleasing to my ear. I'm working on the x-over trying to use as few parts as possible and using the best caps, coils, and resistors I can afford.
I'm one of those DIYers that thinks there IS an audible difference between one capacitor and another. Coils and resistors, of course, can reduce the driver output so a coil with fatter wire offers less resistance.
I'm thinking I can eliminate a BSC (baffle step compensation) by reducing the nominal size of the ported enclosure PLUS tuning the box higher than the Fs of the driver by a slight bit. According to WinISD the upward slope of the driver response as the Hz goes down in a smaller box tuned a little higher would match the upward slope produced by a BSC. Less parts in the signal chain is a good thing. Less parts to add distortions or coloration.


----------



## robbo266317

Capacitors can play a big part in the sound of a speaker. 
When I made my speakers (A long time ago) there was not the selection of high quality ones that are available today. Interestingly a supply of low cost, high quality, high voltage caps were readily available right under our noses - fluorescent light power factor capacitors!


----------



## ISLAND1000

robbo266317 said:


> Capacitors can play a big part in the sound of a speaker.
> When I made my speakers (A long time ago) there was not the selection of high quality ones that are available today. Interestingly a supply of low cost, high quality, high voltage caps were readily available right under our noses - fluorescent light power factor capacitors!


`
LOL, I've never used a fluorescent light capacitor for anything but the light.
What is the Mf rating if you know? I'm guessing the voltage would be somewhere around 200V.
AND as far as their being right under our noses . . . . well maybe if you're Karrem Jabbar.


----------



## Odougbo

Certainly the tweeter cap(s) can make a difference - I draw the line here though:

e.g. 
http://www.madisoundspeakerstore.com/sa-cap-630vdc/claritycap-3.9-mfd-sa-range-polypropylene-caps/

A good three way will sound better than a 2-way, can't beat t good mid range. However, I still like the small front on two way; I really enjoy imaging!!!


----------



## robbo266317

ISLAND1000 said:


> `
> LOL, I've never used a fluorescent light capacitor for anything but the light.
> What is the Mf rating if you know? I'm guessing the voltage would be somewhere around 200V.
> AND as far as their being right under our noses . . . . well maybe if you're Karrem Jabbar. :rofl:


I have a 2.8 uF and 4.0 uF 440 VAC along with a 32uF 330 VAC (we run 240 VAC mains here)


----------



## ISLAND1000

I consider Clarity Caps very good.
Good performance.
Good quality build.
Reasonable price.


----------



## ISLAND1000

robbo266317 said:


> I have a 2.8 uF and 4.0 uF 440 VAC along with a 32uF 330 VAC (we run 240 VAC mains here)


`
Oh yeah, I forgot you're down-under.


----------



## Odougbo

This foil Goertz inductor was only $3 more than the wire wound; same awg.

The bass is tighter, however, it's raining here so hard to tell really.

(BR boxes sound deeper when it rains)

EDIT: watched some moves last night, really great tight bass, subwoofer sound.


----------



## Odougbo

New construction Pic 

arty:


----------



## Odougbo

Almost there - need to make "tray" bases to conceal the xo parts.

New: solid wood vents (vs mdf) and extra wood strips to finish end grain.

Sound? very nice, easy to listen to, remarkable solid/punchy bass; easy to hear movie dialogue.


----------



## robbo266317

I wish I had the time and space at the moment to make things like you are doing.

Very nice work. Two thumbs up! :T :T


----------



## Odougbo

From an avid speaker grue! a fair assessment: 

Take it into context that we are talking $35 tweeter and woofer here. A lot of speakers in this range are just plain bad. These may just be the winners at the price point. I have not found a cheaper tweeter that I can stand at all, let alone hold it's own and the SF is a similar bargain. Even at this price, the quality of the crossover components is evident, not wasted. Something to think about. Full disclosure, I just don't like the XT25 much, feeling $20 more for a Seas is well worth it IMHO. A better woofer is a bigger jump. These are a well matched pair and when properly executed will make a very good showing of themselves.

I can verify these are getting pretty good. We were listening with no sub. Their f3 is in the 60 or so range so his description of real base is valid. Not the sub part, but real.  The cabinets are a bit oversize (12.5L), but instead of a peaky roll-off as you expect in a too-big ported box, they sound a bit more like a sealed box rolling of easy to blend with the room. Doug's port design here needs further investigation to see what it is doing. The asymmetry bothers me in concept, but it seems to work.

Joni Mitchel (Morgantown) did pretty well being properly balanced. Joan Baez (Diamonds and Rust) was just a tad off. close. Their voices are just plain hard to get right. Harry James will show you why you may want to spend twice as much for a tweeter. Crank them high enough for Gliere (The Red Poppy) and you see where paying 5 times as much for Scan Speak comes into its own. Imaging was hampered by the too close bright wall. It was focused, but constrained within the speaker width. Real living rooms do have limitations.

[He left out BACH Toccata & Fugue / First Church...crazy!!! I laugh out loud every time I hear it]

These are just about ready for prime time. Maybe a bit of creative "Penguin" paint. Just one pair. (The WAF would not be good but the photo would be great)

Those without test tools should be heartened as he has done these entirely by ear. 

[FYI Madisound crossover]

Odougbo


----------



## Odougbo

Well I was close....looking at my own photo, I see one wire needs to moved 

Grounded the woofer notch filter on both sides :rofl: (which will be an easy fix).

It did sound okay, maybe 3 parts I don't really need :dontknow:


----------



## robbo266317

What is the notch filter for?


----------



## Odougbo

Some feq in the mid I suppose; it didn't sound bad at all without it (but all fixed now). I'm thinking the big coil is 95% of it.

Ordered some more matrix boards, at least I have a good starting point now


----------



## ISLAND1000

The notch filter is noticeable only when the particular frequency being attenuated is being played.
An unfiltered frequency requiring a notch filter, generally creates listener fatigue when your ears identify the obtrusive "peak" and attempt to avoid it by adjusting inner ear responses or aggravating the listener enough that he removes himself from the irritation . . . . decides he's going to do something else other than listen to those irritating speakers. Even listening to one's wife might be more enjoyable if the frequency peak is loud enough say 6db or more.
A 6.5 inch woofer usually has a peak in the area of cross-over ie: about 2500Hz. The better woofers have a peak somewhere in the 4-6 db range. Occasionally a less expensive woofer will have an additional peak around 300-500 Hz. It's difficult to recognize by ear that a particular driver has a peak. Generally a sweep/graph has to be made and recorded to recognize a peak that needs treating. 
A 3 part notch filter (capacitor, resistor, and inductor) can be adjusted for frequency width (cap and inductor) and depth of cut (resistor).
Algorithmic formulas can be designed to suggest the filter component value but final adjustments are made while installed in circuit.
The "better" speakers have the frequency response adjusted to eliminate peaks and have crossovers that allow the response to minimize comb filtering effects and match phase across a wide frequency band.
All this electronic wizardry comes at a price.


----------



## Odougbo

I do wonder how effective a 3 part circuit can be, seems a bit mysterious. One can always clip lead over to see if it is really hitting the mark. 
I've have speakers that just drove me crazy, more than the ball-n-chain :heehee: These grab your attention, the imaging, rich bass lower register are the highlights.

The Silver Flute woofer is impressive, as my buddy pointed out, they can work in a box slightly larger than simulation(s), and work fine. I would only use them with a 1.5mh series inductor.

I really like this idea of an outside xo, I don't want all those parts inside my box :rolleyesno:

update - crazy imaging with the new xo, WOW! also getting more sounds than I've ever heard, I'm really liking these!!


----------



## ISLAND1000

You've got some nice looking units. Well done.
It's useful to keep the X-over outside the box until you're thoroughly convinced you've got it right.
Otherwise, you might end up taking the drivers out to get at the X-over to make changes.
As you spend time listening to the speakers and listening to various kinds of audible material, you may decide the tweeter is too loud, or the X-over point is too low, or some other process you "hear" that can be improved.


----------



## Odougbo

*Re: Crossovers*

Now what if I wanted to put the xo in base? The feed wires would be 24"- 30". I don't see that a issue, but could I guess.

4 completed boxes/stands, my buddy also has a pair, he's going to see if he can upgrade/tweak them.

He's liking the $29 woofer so far though.




ISLAND1000 said:


> You've got some nice looking units. Well done.
> It's useful to keep the X-over outside the box until you're thoroughly convinced you've got it right.
> Otherwise, you might end up taking the drivers out to get at the X-over to make changes.
> As you spend time listening to the speakers and listening to various kinds of audible material, you may decide the tweeter is too loud, or the X-over point is too low, or some other process you "hear" that can be improved.


----------



## ISLAND1000

You can put the X-overs in the base or anywhere it's "handy" or "complimentary" or even "artistic" if that's possible. 
X-overs don't have any visible moving parts except in the electronic realm so visually they are unexciting. But lately, designer capacitors have been produced that have nice looking exteriors, and even some inductors have been wound on semi fancy spools, but resistors are still ugly. So, I guess if you think maybe a platform of electronic components might look somewhat like "war" equipment or even alien space hardware, I say put them inside somewhere away from little prying hands.


----------



## Odougbo

Thanks Island. I may build the xo in the speaker base one day.

Still making these and enjoying them. My buddy has the Prototype boxes; he put new tweeters in them, should be interesting.


----------



## ISLAND1000

I've looked at ALL the great pictures you've posted and I'm still confused about the ports.
I see that the port end that terminates at the side of the box is flared.
Where, inside the box, does the port begin? 
What is the dimension of the port at it's beginning, length and width?

What's that "wire screen " looking like stuff in the back corners?

You mentioned "cork" . . . . where does the cork go?

Is there any "stuffing" (polyfill) in the box?

Is the one round dowel the only "brace" on the inside of the box?

Your woofer choice ( Silver Flute ) is probably the best around for the dollar in that size.

The Zaph Audio website has a test of a whole bunch of mid/woofers and a way to toggle between 2 drivers and all the different test characteristics ie: frequency response, cumulative spectral decay vs frequency, harmonic distortion, and actual measured Thiele/Small parameters. It's excellent material to get acquainted with. It gives you a good idea what drivers (tweeters too) are available at what price and what their performance and measured statistics look like. 
(Silver Flute) tests are included there also. It tests very well even compared to $250 and up units.


----------



## Odougbo

This all started as a "Dr Watson I need you" moment.

_Where, inside the box, does the port begin?_

At the back, the sound goes to the back and turns 180.

_What is the dimension of the port at it's beginning, length and width?_

4-1/4" at the back opening the "vent ports" are 3-7/8" width each - total 12" ID. 

_What's that "wire screen " looking like stuff in the back corners?_

Fabric store pin point sheet, keeps wool stuffing where it belongs and out of the 4-1/4" x 9/16" vent (at back).

_You mentioned "cork" . . . . where does the cork go?_
I add 3" x 3" cork squares on all sides/top/btm; however the inside of the box gets a nice layer of felt.

_Is there any "stuffing" (polyfill) in the box?_

5.5oz - 5.9oz PE wool 

Is the one round dowel the only "brace" on the inside of the box?

No dowel on the last several project, used a cross brace the helps with gluing the front on.

_Your woofer choice ( Silver Flute ) is probably the best around for the dollar in that size._

Agreed.

*These are super easy to build! Just need to remember to cut the width of the sides 9/16" smaller than the top/btm, this makes the gap for back of the port.


----------



## ISLAND1000

I think I got it.


----------



## Odougbo

A few more are done - ordered some more drivers also :gulp:


----------



## Odougbo

Not to change the subject but here's a quick read on BSC 
http://sound.westhost.com/bafflestep.htm

Not sure I-buy-into-it, they use a sphere vs. "box", I never build boxes unless there is a compelling reason.

A simple rectangle/box will often have a harsh/edgy sound: i.e. echo/resonance; from my experiences angled boxes with felt and cork walls and "smallish" fronts work perfectly. 

One other thought; if the round ball speaker was the brass ring of speaker design, they would be 100s of them available.


----------



## ISLAND1000

I question the need for "baffle step" compensation in a crossover also. What receiver or pre-amp doesn't have a tone control or set of bass and treble controls for adding or SUBTRACTING bass and treble?
My Pioneer receiver has a dozen different ways to shape the frequency response including adding a curve which simulates perfectly a "baffle step" using MCACC. Also my Behringer DEQ 2496 and my Crown XTi 4000 have the capability through GEQ, PEQ, DEQ to create just about ANY response curve one could need. 
My challenge has been to flatten the response of the drivers in a two way system and join the two drivers together with a reasonable level of distortion/diffraction, and clarity in a box with the correct/best/least amount of size/space/volume/ and STILL be appealing to the eye.
You seem to have the driver/cabinet/box to your liking and are/were working on the crossovers.
I've got the drivers . . . . . and am working on the crossovers.
I'm still establishing for myself what's needed and helpful, and what's not.
Lots of DIYers insist on a ZOBEL (impedance compensation network). I'm not so sure. The theory seems logical but in applying the theory, there might not be a need if you can pinpoint the Hz of crossover.
Lots of engineers will suggest a notch filter to reduce a peak in the response. However, placing the notch filter into the circuit with a zobel and a 2nd order Likwitz/Riley crossover creates all sorts of additional anomalies. 
Some electrical engineers insist you use 2nd order crossovers or even 3rd or 4th order in special circumstances. Then there are others who INSIST on 1st order ONLY for simplicity and less chance for error.
In the end, it's up to the builder what's used to achieve the particular sound that pleases him. That MIGHT NOT be what looks best in the tests or even what might seem counter intuitive.


----------



## robbo266317

ISLAND1000 said:


> Lots of DIYers insist on a ZOBEL (impedance compensation network). I'm not so sure. The theory seems logical but in applying the theory, there might not be a need if you can pinpoint the Hz of crossover.


With modern amplifier design, the need for a Zobel network is practically redundant as they can handle the loads presented to them much better. 
On the other hand, the cost of adding it is minimal....


----------



## ISLAND1000

robbo266317 said:


> With modern amplifier design, the need for a Zobel network is practically redundant as they can handle the loads presented to them much better.
> On the other hand, the cost of adding it is minimal....


`

The experts I've read about zobel, indicate a need to keep the impedance of the woofer constant by using a zobel while passing through the response curve @ the x-over point. Otherwise the impedance curve is on an upward slope and changing with frequency therefore a specific value for x-over components can't be established.


----------



## robbo266317

ISLAND1000 said:


> `
> 
> The experts I've read about zobel, indicate a need to keep the impedance of the woofer constant by using a zobel while passing through the response curve @ the x-over point. Otherwise the impedance curve is on an upward slope and changing with frequency therefore a specific value for x-over components can't be established.


As you said, it all depends on where you cross them over and what their impedance is at that point.


----------



## Odougbo

My engineer friend asked me; Do you think a perfectly tuned amplifier needs help DOUG? :sweat:

[when we discussed adding a zobel]

:nono:


----------



## ISLAND1000

I'd like to hear an EE tell us a zobel is not needed BECAUSE the rising impedance curve of a driver is inconsequential in the final analysis of the sound quality. Although the components in a zobel are cheap, I'd like to simplify x-over circuits as much as possible if a zobel does not contribute to the sound quality.


----------



## robbo266317

I think the lower order crossovers would benefit more from an added zobel since they cover a larger range of frequencies.


----------



## Odougbo

*Penguin Power*

At it again....new build, although looks the same.

This is the 8" SF in a 1,400cubic inch box. I've been floundering with the tuning:

* I had a volt meter wire on the amp vs. speaker-wish I had a nickle for every time that happened........:rofl:
* The vent strips are 1/2" thickness; which I now think is working fine.

I have a few of the old Morel tweeters, they go down below 2000, so I'll give them a try. But also looking for something new.


----------



## Odougbo

*Re:*

New box pic.... 

I'm liking the Discovery Tweeter, goes very low and handles more power.


----------



## ISLAND1000

Who makes the "Discovery" tweeter and what model number?


----------



## robbo266317

They're getting bigger... When do we see a three way build? :whistling:


----------



## Odougbo

*Crossovers - by Madisound*

Links: 
http://www.madisoundspeakerstore.com/approx-8-woofers/silver-flute-w20rc38-08-8-wool-cone/

http://www.madisoundspeakerstore.co...-discovery-d2606/9220-1-textile-dome-tweeter/

Just got this pair together yesterday, they are sounding very nice, well balanced, good bass, middle, highs.
Some upgraded xo parts on the way; had to double-up in few spots for now. E.g. two 3.3 caps for the 6.8 tweeter cap (one side). 

However even with some of the parts miss-matched (per side), they sound very nice. 

Box shown is 1375 square inches - tuned to 50-51hz

btw. 7.5oz of teased speaker wool - each.


----------



## ISLAND1000

So, which is better BIGGER or SMALLER?


----------



## Odougbo

I think most folks would go for the bigger box, the middle is better. There's more room filling sound also.
However the 6.5's are a wow!!

Going to try two of the 6.5's in a MTM soon.


----------



## ISLAND1000

Re: 6.5 vs 8 . . . . small vs big
`
"There's more room filling sound " . . . . with the big
`
Does that convert to, "the bigger the room" "the bigger the speakers" ?


----------



## Odougbo

I'm okay with smaller, accurate speakers. One main reason I like these front port speakers, they are compact and sound like boxes double the size.

This last pair, I used standard grade Home Depot birch ply and they sound fine, no buzzing, ringing or boom. 
Backs are 1", I glued 1/4" to the 3/4" before running though saw. 

Been holding onto 2 sheets of 5/8" BB grade, next pair will be extra solid.


----------



## Odougbo

I'm liking these now :sn:


----------



## robbo266317

I just found an old link while cleaning up files on my system. It may come in useful one day.

http://www.ajdesigner.com/crossover/crossoverfourth.php


----------



## Odougbo

Thanks Robbo, Any help with xo design is appreciated.
So 2 successful projects going on - the 8" pair sound very nice, nice bass, mid. etc.

Spent most of the day coming up with this (pic). I think most would like this idea of 2 - $29 woofers that have have really nice bass, without sacrificing tightness. 
This combination of 2 - 6.5" is considered a 2.5 (I think) since I'm using a separate xo for the bottom woofer (now a 4ohm load)

I think the next build will be the "same" - but tweeter in middle (as drawn).


----------



## robbo266317

So you are going to kill the penguins? and go for a traditional MTM design...


----------



## Odougbo

now I still have the 8" penguins; some of you folks have to try the front port design :yikes:

Still mixed up on 2.5 vs. MTM. :scratch:

I thought a MTM shared the same xo and a 2.5 is two separate xo (one for the helper woofer)


----------



## robbo266317

Odougbo said:


> Still mixed up on 2.5 vs. MTM. :scratch:
> 
> I thought a MTM shared the same xo and a 2.5 is two separate xo (one for the helper woofer)


That is my understanding of it as well. 
In an 8Ω MTM you need two 16Ω in parallel or two 4Ω drivers in series to get the required 8Ω.


----------



## Odougbo

Okay got it, a little confusing.

Could always add a second amp (a Pseudo bi-amp).

I'd have to use a Y on each amp - which I'm sure adds a host of other issues :scratch:


----------



## Odougbo

I'm really liking the sound of 2 - 6.5s.

The SF are fine, have a nice powerful sound; these look like they may be a step up:

I rather buy two 6.5s at $52.50 than a $90, 7" any day (way more sound).

http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1092

[SF are $29 each, a good deal for a cast frame woofer]


----------



## Odougbo

To the Bat Cave Robin.....POW! :boxer:

Think I need better tweeter(s), to keep up with the dual woofers configuration.


----------



## ISLAND1000

What's the matter with the current tweeter?


----------



## Odougbo

Speaker Nirvana :T

The moral of the story here is : if you build a 2-way xo'ed over at 2K - 3K, best to use a tweeter with a chamber (shown - ScanSpeak D2606/9220). 

These sound great now, full body sound and crazy low bass.


----------



## Odougbo

Still making these 5 pairs now :gulp:

I'm liking the flares ones better - bass like a 1812 civil war cannon; although the top/bottom port(s) boxes are only 9.5" wide and have very similar characteristics.


----------



## robbo266317

You certainly have a nice finish on those boxes. :T

Why are you making 5 pairs? :scratchhead:


----------



## Odougbo

HELP somebody stop me..........:coocoo:

What to build next? :sweat:

Stocked up on BB ply and medex board (which paints better than mfd)


----------



## Odougbo

This is the last set! 

MTMMM 80liter monsters 8 - 7" woofers, that may go down below 30hz.


----------



## Odougbo

Still Going ...:run::run2:


----------



## ISLAND1000

LOL, your cabinets are getting better and better . . . . bigger and bigger!


----------



## Odougbo

Ended up with five sets of MTM's.
I'm liking the lower left MTM's with SF's 8" 8ohm woofers best. 
The woofer center to center is only 11" with the SB 29 tweeter.
Very natural sounding, nice bass and rolls off nicely, so can be used with or without sub(s).


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## robbo266317

I hope you are enjoying the fruits of your labor now that they are all finished.


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## Odougbo

Finished? :innocent: Can't stop now. 

Watched Oblivion with the big white speakers, pretty crazy; 2 of them sounds like a room full of speakers, including subs :hsd: 

I'd like to try a mtmmm with the SF 6.5s.


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## perceval

Odougbo said:


> Still making these 5 pairs now :gulp:
> 
> I'm liking the flares ones better - bass like a 1812 civil war cannon; although the top/bottom port(s) boxes are only 9.5" wide and have very similar characteristics.


Nice! 

One question, if you don't mind...

Are the two woofers separated and have their own "space" or are they using the whole speaker volume?

I can see a brace in this picture, but I couldn't tell if the brace went all the way to seal the top woofer from the bottom one, or if the brace is opened to let air flow inside and out from the side/top-bottom bass vents.


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## fusseli

The picture looks like the two air spaces are divided...


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## robbo266317

fusseli said:


> The picture looks like the two air spaces are divided...


I think that it is only a brace as it looks like it is at the same height as the tweeter (Which doesn't appear to have an enclosure)
So I guess they share the space.


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## perceval

robbo266317 said:


> I think that it is only a brace as it looks like it is at the same height as the tweeter (Which doesn't appear to have an enclosure)
> So I guess they share the space.


That's what I couldn't figure out from the 2 pics.

1st one looks more like a dividing panel, but in the 2nd pic, you see the tweeter at the spot of the panel/brace.

Just wondering if there was not more "tweaking" done that we don't see in any of the prior pictures... unless it is a building secret, of course!


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