# DIY Speaker Project preparation...



## Sonnie (Apr 11, 2006)

I have an IB install planned soon... now that the weather is cooling off and grass will quit growing... I'm telling ya, keeping up all this land is a major job during the summer. There's just no extra time to get serious about anything. Cool weather brings lots of extra time for me. The IB project should get done as soon I can gather up the rest of my tools.


Next after the IB project is the possibility of some DIY speakers... I'll probably start with a Center speaker and then build the Left and Right speakers. This doesn't mean I'm never gonna buy speakers again, it just means I wanna play.

The finish is settled... it will be a black texture painted finish. I'll probably get Rodny to help me paint the cabinets. Basically I'll have towers of some sort built out of 3/4" MDF.

I would like towers from about 42" to 50" tall... no more than 8.5" wide and however deep they need to be to get the response I want.

I'd like a response to about 35-40Hz on the low end.

My thoughts are a WWMTM or WWMT for the L/R and WMTMW or WMTM with the T stacked on top of the M. 

These will be used mostly for HT.

Yes, I was at once considering letting someone else build them for me, but I really don't have the money to do it and have other manufactured speakers I want to buy later on when they are released... so in the meantime, this will be my little project. Cost wise I don't wanna get crazy with the most expensive drivers but rather something that will get the job done well enough.

I'm looking for recommended drivers and crossovers to begin with and then I suppose I can figure the box size I'll need from there.


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## dynamowhum (Oct 3, 2006)

I highly recommend HTguides mission accomplished area. They have several designs to llook at. I built the Dayton RS 3 way with the Dennis Murphie designed crossover in a sealed box and I just love it. I am building the Nat Ps as the mains. Depending on how you build them the CC ran around $400 depending on finish and quality of cross over parts. Hope this helps.


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## Sonnie (Apr 11, 2006)

I've heard a lot about Nat Ps... seems those are popular. I might take a peek over at HTG and see if something grabs me, but those threads over there are almost information overload.

Finish will be that black texture... fairly inexpensive. They'll be in a dark HT room so I definitely don't have to impress anyone with looks, however I do want them to look neat and uniform.

Have you got pics of your Dayton RS 3 ways?


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## dynamowhum (Oct 3, 2006)

Yes I do but mine is just raw BB plywood and MDF. I will post those tomorrow if you would like. All my front stuff will eventually be behind a procenium so I am not that concerned about finish either. However I still want them to be right incase I decided to bring them out to the light of day.


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## Sonnie (Apr 11, 2006)

Yeah... if you don't mind tell me the drivers and crossover you used and show us some pics. Just reference the thread here so I'll be sure not to miss it.


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## dynamowhum (Oct 3, 2006)

1 DAYTON RS28A-4 Unshielded http://www.partsexpress.com/pe/psho...tnumber=275-130
1 DAYTON RS150S-8 Shielded http://www.partsexpress.com/pe/psho...tnumber=295-362
2 DAYTON RS225S-8 Shielded http://www.partsexpress.com/pe/psho...tnumber=295-366


The cross over design was Dennis Murphys WMTM center channel.http://htguide.com/forum/showthread.php4?t=15323&page=1. 
If you paste the link in your URL in will show you the first page. There is a lot of information over load and many different designs for this center.
This thread is attempt to cut through all the pages and give quick reference to the various designs. http://htguide.com/forum/showthread.php4?t=22393

This is one outstanding speaker. The box dementions are 26"X12"X18". My box weighed in at 70lbs. I mainly listen to HT but I did put the cable boxes music channels through it and it was outstanding especially when couple with the IB. From classical to rock to jazz and blues this thing really rocks.

My daughter took my digital camera to school today so it will be tomorrow before I can post pics. Since this was my first true full range speaker project I made a seperate crossover box to get at the electronics easily if I had made a mistake. So I will post pics of the crossovers as well.


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## JCD (Apr 20, 2006)

Pretty exciting stuff coming up.. I can't wait till you start!

So, you were rather vague about your budget. Can you be more specific?

That being said, someone I know and who has heard several kits has made recommendations about what he liked.

All of the Seas kit's (Thor, Odin, Froy, etc..) are great. The Thor's were his favorite.

A little less expensive would be the Vifa Big A/V kit from Madisound.

Another project in the same ballpark is the HiVi K Project.

Farther down the food chain is the JML-5 MTM and JML 6-MTM kits from Zalytron.

Those were all bookshelf speakers -- which could be converted to a floorstander easily.

The ErosMKII is another good speaker that is a floor stander by design.

A fairly large range of prices there to choose from. 

Oh, the person that recommended the above like a "neutral" sound. For reference, in the retail market, he likes Paradigm and Dynaudio.


The real fun would be to start from scratch. Of course, for that, I'd probably want to go with an active crossover as crossover design is REDICULOUSLY hard to get right. Of course, the price tag goes through the roof at that point as you'd have to get amplification for each channel.

JCD


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## dynamowhum (Oct 3, 2006)

Good cross over design aint hard as long as you have some one else do the work for you:bigsmile: With so many good designs out there I don't see any need to do it myself. The CC can be made for less than $400 and believe me you wont be able to touch a commerical speaker for triple the price.


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## Brian Bunge (Apr 21, 2006)

Sonnie,

Based on your requirements, the Dayton RS 3-ways would be too big. IIRC, they're around 42"H and 10.75" wide. Now the height isn't really an issue, I know. But the width sure sounds like it would be. At least based on the previous conversations that we've had. You're biggest issue is getting the SPL levels you told me you want while still keeping cabinet width (or center channel height) within your range. I'm building a different crossover with the same drivers in the 3-way center and shrunk the cabinet height down to 11.5", but that's still well above your height requirements. This is going to be an issue with any vertically oriented TM alignment in a center channel were you're using a 5.25"-6.5" mid and a tweeter with a 4" or so diameter faceplate.

To keep cabinet width down you can throw in multiple 7" woofers instead of the dual 8's in the Dennis Murphy 3-ways, but you end up with about the same cabinet volume and probably higher cost due to the multi-driver array. You end up having to make up for the volume by increasing cabinet height and/or depth.

My first instinct is to tell you to build these 3-way because I know how good they can sound, based on my experience with the RS drivers. Since I don't think that you can quite make that work, your best bet might be to see if you can get Dennis Murphy to design something for you. I don't believe he charges anything, but he normally does require you send the cabinets and drivers to him so that he can take measurements and do the design work.

Other than that, if there's anything else I can help you with, don't hesitate to ask.


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## Sonnie (Apr 11, 2006)

I'm probably gonna go the Dayton route with drivers... they seem to be fairly popular and inexpensive as well. 

When it comes to crossovers, I'm about as clueless as they come. 

I'll probably go with:

RS28A-4 Tweeter









RS125S-8 5" Midrange X 2









RS180S-8 7" Woofer X 2










For the Center I may go with 4 of the 4 ohm 6" Woofers.


This would give me the WWMTM for the L/R and a WWMTMWW for the Center. That may be overkill for a center though.


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## JCD (Apr 20, 2006)

Came across this site that does a quickie review on the various online retailers for kits..

And yeah, designing a crossover is going to be TOUGH to do right.

If you do decide to go all the way with the design, you should increase the size of the woofer. I'd think at least 10" would be the way to go. Seems like there would be too much overlap between the 5" and 7" drivers. 

Finally, if you do decide to go all the way with a design, I'd stick to a 2 channel system rather than a 3 way for your first go at this. Crossovers with 2 channels are hard. It just gets exponentially difficult when you throw in a third channel. A tweeter and a 7" woofer might be good for a 2 channel system. 

JCD


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## F1 fan (Jul 6, 2006)

Sonnie, you are better off to build one of the finished designs with optimized crossovers for these drivers.The crossover is the key to a good sounding speaker and unless you have the test equipment and design software and lots of time to test and tweak the results will be less than good.On the other hand it can be fun and educational.

You guys south of the border are lucky to have available these fine Dayton drivers for such reasonable prices.


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## Sonnie (Apr 11, 2006)

Okay... you guys do pretty well at talking a guy right out of DIY speakers. If I can't build what I want then I ain't gonna build'em.

If it's possible to do a WWMTM or WWMT L/R and a WWMTMWW or WMTMW Center no taller than 8.5" high, then I'll go for it, otherwise, I'm not interested in anything else. 

I also don't have a problem with WWWT or WWWWT L/R and a WWTWW Center. Either way, I want more drivers.

I am not gonna do a MT or WT or WMT... nor am I gonna use anything larger than a 7" driver.

As originally stated, I would like towers from about 42" to 50" tall... no more than 8.5" wide and however deep they need to be to get the response I want. If 7" drivers want work then I don't mind using 6" drivers.


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## Brian Bunge (Apr 21, 2006)

Sonnie,

Oh it's possible, you'll just want someone design the crossovers for you. The only reason 7" drivers wouldn't work is if you wanted to do heavily rounded vertical edges on the front of the cabinet. With an 8.5" wide baffle you could get away with about a 1/2"-5/8" roundover on each side because the 7" drivers have a frame that's slightly larger than 7". This basically just means you can't do a full 3/4" roundover. 

Other than that, you should be good to go.


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## Sonnie (Apr 11, 2006)

Okay.... then I will probably need to back up to the 6" drivers. I think those 7" drivers are 7.25" outside dimensions. 7.25 + 1.5 = 8.75 ... that's cutting it too close. I'd say the cabinet would really need to be 9.5 - 10" to look right.

I think the 6" is 1/16 under 6" so with a 3/4" roundover I'd be looking at pretty much 7.5" ... that's still pretty close... only leaves 1/2" between speaker edge and where the rounding begins. I could probably live with that.

So would it be easier to plan for all woofers and a tweeter or maybe the woofers with the 2" midranges? 

Keeping in mind this is for HT, not critical listening... is using midrange drivers that important? 

Would I be better suited and it be easier to design if I went with say 4 x 6" woofers and a tweeter and do a two-way design?


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## F1 fan (Jul 6, 2006)

Separate Mids are not neccessary you could forgo them and build a high quality MTM like the Thor that JCD mentioned.http://www.madisound.com/thor.html The drivers are pricey but they are amongst the best available.

Another less expensive but good looking design (WMT 2.5 way) would be Zaphs waveguide design. http://www.zaphaudio.com/Waveguidetmm.html 
Both of these should perform great in an HT especially with bass management relieving them of deep bass duties.


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## Owen Bartley (Oct 18, 2006)

Wow, Sonnie, you have some serious aspirations here! Has anyone done a WWMTMWW Centre before? I like the Daytons, and as mentioned there's a huge thread about them at HTG, but the detail lost me quickly. It sounds like a lot of your preferences are the same as mine, with a few woofers and a narrow baffle, and decent low end response. I wonder if a WWWMT would make sense, to get some good low end extension? It might just make things too complicated. I know next to nothing about full range speaker design, crossover design, etc... but I can tell you they sure would look purty! :dumbcrazy:


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## Sonnie (Apr 11, 2006)

Yeah... same here with the HTG section... :dizzy:

Hopefully I can figure it out... otherwise I'll delay it or forego it.


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## Owen Bartley (Oct 18, 2006)

Don't let it get you down Sonnie. All it will take is some dedicated reading time, bookmark a few of your favourite projects, and compile a list of questions. Just make sure you don't rush into it and you should be good.


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## JCD (Apr 20, 2006)

Had a thought, what about a line array with a single full range driver? You could use this one that was well liked by that Zaph audio guy. Why? Relatively inexpensive and no crossover needed. With a 50" tower, you could get 10-12 of these guys in the array I'd think.

What's involved with designing a line array? No idea.. but here is a paper you could read that may help. I think they go into some of the details with ribbon and woofer designs, but I'd imagine there is something in there that should help. 

If you decide to go with a tweeter/mid design, it'd still be simpler to design the crossover than going with a 3 way design.

JCD


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## F1 fan (Jul 6, 2006)

Another possibility is to build a pair of Nat P's or similar MTM then use an active crossover in the 200-300hz region to 2 or more 7" woofers.This way you would have a proven MTM design with the passive crossover work already done and you can go with a WWMTMWW if you wanted and had the vertical space.An inexpensive Pro amp would suffice to drive the woofer section.


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## Sonnie (Apr 11, 2006)

I don't think the 3" full range would ever be able to give me the low end response I want. Brian with RAD has a similar designed speaker that I really liked but it is limited on the low end.

I'm surprised that no one has done any larger array of drivers... more that a MTM or WMT.


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## JCD (Apr 20, 2006)

I guess it depends on how low you wanna go, but this one says it goes down to 25Hz with a little bit of EQ'ing.

Of course, he uses 25 3.5" drivers instead of my proposed 15 (redid the math, and you can definitely get 15 in there).

In any case, all you'd really have to get down to is ~80Hz with your two SVS subs.

That being said, how about using the Dayton 5" and Dayton tweeter you have in a MMMMTTMMMM configuration? That should provide plenty of low end extension, especially with the the 2 subs you've already got. With this configuration, and based on the numbers I plugged into WinISD, you'd need an internal volume of 2208.4in^3, which could be 50x6x7.36 (HxWxD) for a vented enclosure. For a sealed enclosure, WinISD came up with less than half of that. This assumes I plugged the right numbers in to the program. Of course, you'd have to design a crossover, but at least it's only two way.

JCD


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## Guest (Oct 23, 2006)

JCD said:


> I guess it depends on how low you wanna go, but this one says it goes down to 25Hz with a little bit of EQ'ing


I auditioned those yesterday at the 2006 RMAF. Powered by a ton of McIntosh's best electronics, the speakers sounded terrible. The high frequencies were so bad I could only stand to stay in the room for ~30secs.....beware..:thumbsdown:


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## JCD (Apr 20, 2006)

Ok, so it looks like the full range driver idea might not be so good..:sad2: or at least in this application, which for $18k/pair would probably include a lot of stuff more modest than that. It's surprising and disappointing given the designer's pedigree. :rubeyes: 

So, back to my MMMMTTMMMM idea... :demon: 

Also, ThomasW, you mind giving a quick run down of the stuff you saw at the RMAF this year? 
<edit> Although, maybe in another post so we don't hijack this one

JCD


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## Owen Bartley (Oct 18, 2006)

I would love to see the development and results of a MMMMTTMMMM design. I've looked a little bit at line arrays myself, but I just can't convince myself they'll sound right. I am curious though, why 2 tweets in this design? Wouldn't that confuse the imaging a bit?


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## JCD (Apr 20, 2006)

Owen Bartley said:


> I would love to see the development and results of a MMMMTTMMMM design. I've looked a little bit at line arrays myself, but I just can't convince myself they'll sound right. I am curious though, why 2 tweets in this design? Wouldn't that confuse the imaging a bit?



First off, I know very little about the actual design, I'm going off of instinct more than anything.
I have seen many line arrays actually that have a lot of tweeters.. usually (all?) ribbons from what I've seen/remember. 

That being said, my thinking was that it just seemed like a good idea at the time -- IOW, I dunno.. :dontknow: probably just one of those "that's a lot of woofers, might as well have a couple of tweeters in there too". onder: 

However, I think I saw that he got a good deal on some JBL's, so this project may have just died. :sad2: :crying: :hissyfit: 

TKoP


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## Owen Bartley (Oct 18, 2006)

OK, so you're around the same "that would look cool!" level as I am. :1eye: 

You're totally right though, I remember seeing a bunch of ribbons put end to end in other LA projects, and those guys must know something about what they're doing.

e: Oh no, just read the last line again! I really wanted to see some plans!


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## F1 fan (Jul 6, 2006)

Two tweets operating over the same frequency range will cause cancellations and result in a narrowing of the vertical dispersion therefore there will be a reduction in the amount of hi frequency reflections from the floor and ceiling.This can help in a bright and live sounding listening room but it also narrows the sweet spot.Dynaudio and M&K have built speakers with multiple tweeters but they may have limited the bandwidth of one of them so not as much cancellation would occur.In fact M&K made or still makes models using three dome tweeters.


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## Sonnie (Apr 11, 2006)

A multiple array unit would be cool looking no doubt. I'd be satisfied with a MMTMM for the Center and MMMMT or MMMTM for the Towers... both 2 way designs. Go with four 6" drivers in each cabinet.


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## dynamowhum (Oct 3, 2006)

Sorry for the late posting of pics daughter had the camera off in Neverland. Well the IB is 2 15" atlases the center channel is the DM dayton mentioned in an earlier post. The electronics are the crossovers for it.


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## dynamowhum (Oct 3, 2006)

These boxes are the begginings of the Natalie P project that is non-bsc sealed. The front baffle is 2" thick with 1" BB ply and 1" MDF. Working with Thomas W on some bass bins for them.


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## Sonnie (Apr 11, 2006)

The Natalie P's seem to be pretty popular. Why two levels of bracing and a 2" front baffle?


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## dynamowhum (Oct 3, 2006)

Bracing and extra thick baffle for a dead box.


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## Sonnie (Apr 11, 2006)

I wonder what would happen if you built another section with the same amount of airspace below that unit and installed two more M's and wired them in with the current pair of M's. MMMTM. Would it work? The air space for the two new drivers would be separate air space from the MTM airspace, yet the sections would be connected together and the drivers wired together.


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## dynamowhum (Oct 3, 2006)

I am going to be putting some PE RS 315 12" woofers in some bass bins and place the Nats on top of them. I will be actively crossing them with with one of the behringer units at about 250hz down to 80hz. If you went with two more mids you would have to come up with another crossover design.


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## Brian Bunge (Apr 21, 2006)

Sonnie,

To do what you describe would require a complete crossover redesign. The extra drivers would bring the impedance up to 8 ohms on the woofers and would also affect the baffle step, which would have to be taken into account as well.


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## Sonnie (Apr 11, 2006)

Could you not just use 4 ohm drivers series/parallel to keep the top two at 4 ohms and the bottom two at 4 ohms? 

I don't understand what you mean by "baffle step".


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## dynamowhum (Oct 3, 2006)

BSC Baffle Step Compensation. I don't pretend to know much about speaker design but if you have a wall mounted speaker or one less than say 2ft from the back wall you need non BSC crossovers. It has to do with crossover implementation. My Nats will be up against the back wall and sealed so I went with the new non BSC design. Your speakers will not image properly if your speaker placement is wrong. I know that is basic but you have to know your cross over design to do it properly.


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## Brian Bunge (Apr 21, 2006)

If you series/parallel the drivers you'll end up with 4 ohm load if you're using four 4 ohm drivers or an 8 ohm load if you're using four 8 ohm drivers.

Rather than trying to explain baffle step to you I'll link to an article by John Murphy of TrueRTA fame: http://www.trueaudio.com/st_diff1.htm


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## Sonnie (Apr 11, 2006)

Yeah, I understand series/parallel... but you said extra drivers would bring the impedance up to 8 ohms on the woofers... indicating it would be a problem. I assumed you were meaning the impedance needed to stay at 4 ohms. What I meant was that it should not be a problem to keep it at 4 ohms.


As far as baffle step or diffraction loss.... what would happen if you took an extra Nat P and took the tweeter out and place it underneath the other Nat P... then swapped the four woofers and wired them together to achieve the same impedance? The top Nat P's still have their own enclosure and the bottom ones do too, but we just didn't add the tweeter to it. I don't see how that changes the baffle step since it's already proven... or does it change it because of the vertical height has been changed? In that case, it would not be wise to use full sized stands creating extra baffle below the original Nat P's. :scratch:


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## Brian Bunge (Apr 21, 2006)

Well, changing the impedance from a 4 ohm speaker to an 8 ohm speaker means that the values for the crossover components change, basically meaning you'd have to redesign the crossover. Also, adding 2 more drivers increases the bass output of the speaker, which decreased the amount of baffle step compensation needed, which requires redesigning the crossover.

Also, there's much more difference between the 4 ohm and 8 ohm Dayton RS drivers other than just that and the shielding, so you'd have to redesign the enclosure based on the fact that you were using the 4 ohm drivers. 

So either way you look at it, any changes you make are going to require that you either modify the crossover or the enclosure, or both.


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