# Anarchy 2.5way PE 1ft³ design in progress



## SturmMD (Dec 30, 2008)

I'm slowly starting a new design for the anarchy drivers I purchased recently.
I will be working on it slowly and going through the entire process taking measurements 
on a test baffle to tweak the tweeter position and design the crossover.

For the tweeter, I'm using a Vifa DX25TG which I have on hand.
I expect to use a 2nd or 3rd order crossover around about 2kHz.

So I can focus my effort away from the cabinet construction, I'm using a PE 1.01 ft³ 
curved-side cabinet and plan to put them on 16" stands.
It has a front baffle that is 9x22" and I'm able to squeeze it all in. 
I may require adding additional magnets to lift the grill so it's not flush with the baffle though.

For the port, I decided on a 3" flared powerport to keep the velocity low enough. 
With the full port length, the tuning can be as low as 34hz.
I'll probably settle on something between there and 40Hz.
By carefully examining the cabinet datasheet, I determined that it is possible to fit the 
port cutout behind the internal cabinet brace.
I hope to flush mount the port in the bottom of the cabinet.










After subtracting the drivers and port, there is somewhere between 25-26L of volume

I just bought a router and spent some time learn making recesses and cutouts.
The following picture is the first baffle I made for practice.










I placed the tweeter to give the best overall diffraction in simulations. 
It is 1.75" off-center and 4.5" from the top. I hope to verify this in my measurements.



ps. for those in the know... yes, I'm still working on the adjustable ssf project. 
It hasn't been forgotten, just slow progress coding and major time limitations


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## Ryan Anderson (Jul 20, 2009)

What do you project total costs to be per unit to build?


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## SturmMD (Dec 30, 2008)

Ryan Anderson said:


> What do you project total costs to be per unit to build?


About $350 each in total, even the stands


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## dyohn (Apr 17, 2008)

What sort of crossover topology are you using?


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## SturmMD (Dec 30, 2008)

dyohn said:


> What sort of crossover topology are you using?


Right now I'm thinking of using a parallel crossover with the woofers in parallel too. I haven't done a 2.5 way design yet, but right now I'm planning on putting the baffle step compensation circuit in series with one of the woofers, just before they connect in parallel


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## SturmMD (Dec 30, 2008)

Here is an update.

Here is the figure I used to evaluate if the 3" port could fit. 
I just took a screenshot from the cabinet's datasheet, sized it appropriately 
in an editor and then drew in the recess and cutout circles for the port size.









Here is the port recess cutout. I used a stairstep pattern to follow the flare 
radius instead of making a large cutout.









It looks nice









And here is an image showing the port clearance.








In front and behind the port there is more room; the nearness
of the sidewalls shouldn't be much of an issue.
With the full port length (2 flares, and 11" ? extension) of about 17" it comes 
within 3" of the top. 

Here is the first baffle.
I used contact paper to protect it while I was doing the routing.








Everything is flush mounted and very tight  thanks to the practice baffle.

And the result so far. It is shown from an odd angle, but I just
wanted to get the port in the photo too.








The center of gravity will be close to the front and it will be on a stand,
so that should leave the port with plenty of space to breathe.


I have already done free-air impedance measurements of the anarchy drivers,
before and after breakin. I still have to mount the drivers, then take measurement
and design the crossover.

Sadly, it will be a couple weeks before I'm able to work on the project again.


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## SturmMD (Dec 30, 2008)

Another weekend with some spare time brings this update.

Here are the screws and t-nuts I am using.








I ordered these t-nuts online from mcmaster because they have a smaller 
outer diameter which is important as I'll describe later.

Also, I specifically chose these screws because they are a low-profile version of 
normal socket cap screws. They fit completely within the recess of the Anarchy 
driver's mounting holes as you see below.








I think 8-32 button head cap screws could also work, just check the datasheet to
make sure the head diameter isn't too large. I know 10-32 button heads are too large.


I knew that the anarchy drivers were a tight fit for this cabinets; here are some issues 
I had to consider before deciding on this size box.

First, the drivers must be recessed because they are larger than the inner grill frame.
Second, any interference with how the baffle attaches to the cabinet must be considered.
These together necessitate flush mounting screws and careful consideration of the
screw (and t-nut) locations.

For the best fit and least interference, the Anarchy screw holes are in the 12, 2, 4, 
6, 8, and 10 o'clock positions. This orientation minimizes the number of issues, 
leaving only 1 screw, the bottom one of the bottom driver, which may interfere 
with the grill and baffle attachment.

Here is a photo of the offending t-nut, which was causing the baffle to not sit 
flush on its mount (insufficient spacing marked in red).









And here is the fix... I just carved the baffle framing out a little bit.









For damping I used 1 sheet of 1/2" Sonic Barrier (18"x24") from PE,
and 1/2 sheet of 1" Sonic Barrier (per cabinet).








The 1/2" stuff is in the back part of the cabinet, the brace and a little bit on 
the rear of the baffle. I used 1/2" in the back so won't touch port inner flare.
The 1" foam is used on the sides and top of the front part of the cabinet and
I reserved the bottom for the crossover.

I will probably finish a few more things like mounting the port and some 
wiring this weekend. The finished result is quite a ways off though because
I still have to take measurements and design the crossover.


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## lsiberian (Mar 24, 2009)

In a ported design it's normally suggested to leave half the internal surface untreated. I'd also double up the rear wall if you can. The back wave is the most problematic.


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## SturmMD (Dec 30, 2008)

lsiberian said:


> In a ported design it's normally suggested to leave half the internal surface untreated. I'd also double up the rear wall if you can. The back wave is the most problematic.


 Thanks for the suggestion about the rear wall. I think I'll leave it like this for now, the curved cabinet sides should spread the backwave - the rear flat is actually less than 1/2 the front width.
As far as the % coverage goes, I thought about that a little bit but then I decided to cover the whole thing to reduce any possible cabinet resonances without going back and adding more braces. Also, I justified to myself that because the back of the baffle is nearly untreated, and half of my treatments are 1" and half 1/2", and I'm not using expensive treatments that this is equivalent to 50-75% treatment 
I'm also only assembling 1 cabinet right now, so I have a second attempt at it.


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