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Zilch's AK Design Collaborative - Econowave Speaker

Group buy for badges available to subscribers in bartertown now!:
http://www.audiokarma.org/forums/showthread.php?t=358179

here's one of the preproduction tests (poll in above link will decide final finish):
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P.S. hopefully these will be available to everyone on zilchlab.com someday, but definitely no promises on that! Get 'em while they're hot.
 
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Crossovers for Model 14

This design I have from Richard Christiansen (this is my drawing though). The origninal Altec Model 14 crossover cannot be found online it seems, but this is Richards alternative. He includes these notes with it:

The 2.1 mH and 7 ohm values are measured from a model 14 woofer.

The .155 mH and 6.8 values are measured from an Altec 902 driver.

The 25 uF and 10 ohm resistor are the Zoble network.
Click to expand...

Richard also mentioned that the Altec crossover ran the woofer full range, and he got a definite spike when he applied a 'normal' crossover, but adding the Zobel cured that problem.

This design crosses over at 2000. The Altec spec is 1500, but Richard found he got better results (less honkiness) if he didn't make his horn go that low, and this woofer can do it.

I'm thinking to use the low end section from this design, and the top-end part from the econowave standard crossover. Should work?

ON EDIT: my initial circuit drawing contained errors. See message 12867 from EarlK below. ATTACHMENT REPLACED WITH CORRECTED VERSION.
 

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4343 said:
DE250 is 2 or 3 bolt driver while D220Ti is 1-3/8" thread. Are you planning on performing surgery on the waveguide? (It's been done before.)
Click to expand...

Just what Zog666 said :yes: I would like to find the plastic version of adapter because it is easier to mod (like Gainphile did). Look at this...

http://redspade-audio.blogspot.com/2011/03/waveguide-shootout-2-measurements.html

I've seen what you did with your WG to make it bolt on and i loved it :thmbsp: . The thing is that there were no measurements with that moded waveguide and since i don't have measuring gear, i gave up the idea.

But it still looks like the best mod because you've managed to avoid the lenght of the throat area that made that FR dip in HF with bolt on adapter for DE-250/JBL WG combo.
 
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(A) The following components shouldn't be in your schematic ; ( R2, L2 ) & ( R6, L4 )
- ie; You've misinterpreted Richard C's schematic .
- They are simply electrical equivalents ( Resistive & Inductive stand-ins ) for both the actual woofer & tweeter ( to help make Richards' electrical simulation run a bit more accurately ) .

(B) Erase that line that you have connected to the bottom of the woofer ( going all the way back to the positive input ) .
- As drawn, that line bypasses ( & therefore , effectively shorts out ) all the included low-pass components, making them useless .
- ie; As drawn , the woofer is running full range .
- Connect ( extend the line from ) the bottom side of C2, to the bottom terminal of the woofer .

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(C) If you find that the horn level is too hot ( once you build this up ) then add an 8 ohm variable Lpad ( from PE ) , wired up right before the tweeter ( after R4 ) .

<> EarlK
 

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Thanks, Earl!

I emphasize that the errors were mine, not Richard's.

Cool that you have a higher resolution image of the Multisim screen than I've seen so far....

I'll fix my drawing and edit the post. Hate the idea of spreading wrong data.
 
Cut and Paste Crossover

This combines the woofer part of Richard's Model 14 crossover (above) and the eWave HF part as adapted by Bwaslo and posted earlier (here). The last was I assume adapted to cross at 2000 Hz, since it was to be used with an Advent Maestro woofer with an OEM crossover at 2000. That's what I want-eWave @ 2000.

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ON EDIT: diagram corrected. Value of L2 is 550 uH. Diagram previously showed wrong value of 550 mH.
 

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hey guys - can someone point me to modding the jbl waveguide for bolt on? I have the adapter already but would like to get rid of the throat if that will improve things.
 
rage said:
hey guys - can someone point me to modding the jbl waveguide for bolt on? I have the adapter already but would like to get rid of the throat if that will improve things.
Click to expand...

I see the link to my pic, thanks for that, foofighter. It works OK, 3-bolt is a real pain, 2-bolt is pretty easy. The plywood is too weak and bends...

Here's how I would do it: Cut the threads off the waveguide fairly close to the throat, but leave a little so you can sand it down to the exact start of the flare. You'll then need to snip off the webs that run down the top, bottom and sides of the rear of the flare. I cut enough to match the depth of my flange, but then cut more for the bolt heads to clear on the sides. If you go with 2-bolt only, align them vertically so there's more room to get to them.

Next, take your adapters and cut the threads off of them, then drill/turn the center large enough to fit over the back of the flare, it need to be flush with the back of the throat.

Once it all fit together you need to glue it together with some strong epoxy. I used Gorilla Glue on the first one I did, and it works OK, but it's not that strong, hardened it's more like an expanding foam. What I did was cover the front of the driver with some plastic wrap before bolting it to the flange to keep the glue out of the throat. Then I put the glue on and used the weight of the driver to press it down onto the waveguide while it cured. Make sure you can get the bolts out before you let it harden in a position that would prevent that!

Two things to remember:

First, the plastic won't stop glue from dripping down the inside of the waveguide. (The Gorilla Glue did just that and needed to be scraped out.) Also the Gorilla Glue expands and needs more weight than just the D220Ti to keep things aligned, thus the epoxy recommendation.)

Second, I would think seriously about supporting the driver on the waveguide after this mod. I ran a brace from the front to the back right under the waveguide, and strapped the driver to it with a big zip-tie. A Neo driver _might_ be OK, but I would still find a way to strap it.
 
There is a very nice pair of Pioneer CS77's available to me, are these a good ewave candidate? They are reputed to be 95db sensitive.

I guess if I was a really good AK'er I would just do it and tell you about it, however, the question stands.
 
You'd have to replace the woofer on the CS-77s, probably. It was crossed to the mid-range at 450 Hz, which suggests to me it won't go nearly high enough for an e-Wave.

Old two-ways are in general good candidates; old 3-ways, not so likely.
 
The E-waves have come back from the disabled list. I got the replacement D220Ti diaphragms from PE yesterday, so I was able to put them back together! :banana:

Once again they're set up in their proper domain, and breaking in the new diaphragms and caps. It's interesting, when I first built these, I remember they sounded pretty raggedy for a little while. These don't sound raggedy much at all, I'm really looking forward to seeing what the well-damped diaphragm back can do with the charge-coupled crossover.

So far, the damping by itself has made a huge difference with the D220Ti driver. It's highly recommended to everyone who uses them.
 
DonQuixote99 said:
You'd have to replace the woofer on the CS-77s, probably. It was crossed to the mid-range at 450 Hz, which suggests to me it won't go nearly high enough for an e-Wave.

Old two-ways are in general good candidates; old 3-ways, not so likely.
Click to expand...

Thanks, I understand the problem exactly.

If the cs77's can be had for $10 or less I may experiment with them and a simple first order crossover. In any case the d220ti's will be a worthwhile investment.
 
jhoyt said:
The E-waves have come back from the disabled list. I got the replacement D220Ti diaphragms from PE yesterday, so I was able to put them back together! :banana:

Once again they're set up in their proper domain, and breaking in the new diaphragms and caps. It's interesting, when I first built these, I remember they sounded pretty raggedy for a little while. These don't sound raggedy much at all, I'm really looking forward to seeing what the well-damped diaphragm back can do with the charge-coupled crossover.

So far, the damping by itself has made a huge difference with the D220Ti driver. It's highly recommended to everyone who uses them.
Click to expand...

Anyone who says that there is break in period with compression driver, that has Ti, Al or Be diaphragm, got to be kidding :) The only thing that does break in with these are ears/brain.

With conventional bass speakers it is the case, but not with compression drivers...

It sounds great immediately because of well damped chamber and good xover :yes:
 
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