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Zilch's AK Design Collaborative - Econowave Speaker

Duffinator said:
And they will probably sound even better when you do. :yikes:
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Getting the WG snuggled up next to the woofer 'spreads out' the nulls that happen in the crossover overlap region and in best case scenarios puts them outside the WG's radiation pattern. Waveguide on top of the cabinet is convenient but the center to center distance can bring those nulls into the forward radiation pattern.
 
Pio1980 said:
Did the measurements include polarized pulse testing to check acoustic polarity and time/phase alignment?

Doing some preliminary experiments with one AR-6, it's x'over, and a JBL 6X6/ D210Ti combo tells me that the WG driver "wants" to be mounted appx'ly on the back of the baffle board to blend the mid's plane with the woof's to bring the midrange "into focus" when auditioned on axis. This could be a deal breaker mounting the 6X6 WG to the B/B, I don't see how the EW x'over could change that.
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Build it and see. Two measurements locating the Xover null will tell you the angle of the plane. Two more will tell you where the driver interference nulls are. It's all going to vary with what woofer you use and the crossover, which alters the phase relationships. Two holes in a piece of plywood, and you're going to have the answers.

The 6" x 6" is shallow, the standard E'Waveguide intermediate, and the 8" x 8", deeper. You'll have to measure them acoustically to determine the relative displacements of their centers with the Selenium driver. If you want to move the driver further back, use the bolt-on version with a throat adapter. The consequences are documented in the thread. Flush-mounting the waveguide in combination with that moves it back further, if desired.

penngray said:
Any discussion in this thread wrt screw on vs bolt on and if the "tube" section of the screw on causes audible issues?

Are all the Econo-wave projects using the "screw on" version?
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Yes, I measured the differences with two different throat adapters. With DE250, no thread-on version is available, and you have to use them; I recommend the inexpensive Selenium adapter available from PE, but if you have the option, don't use one; in detail, it alters the throat geometry.... :yes:

jackgiff said:
I recently bought an oscilloscope to complete my rack mount test station, and while looking for a shelf to rack mount it, discovered a Tektronix R453 scope, already rack mounted. Bought it for my offer of $100. Now the station is complete. Can't wait to get to the next test session.

Now all it needs is a sink. :yes:
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UT, oh, ENGINEER at work; hide yer inductors and capacitors, folks...! :tongue:
 
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Bauhausler said:
Getting the WG snuggled up next to the woofer 'spreads out' the nulls that happen in the crossover overlap region and in best case scenarios puts them outside the WG's radiation pattern. Waveguide on top of the cabinet is convenient but the center to center distance can bring those nulls into the forward radiation pattern.
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If I ever build new cabinets I'll investigate the distance issue more carefully. New cabinets would be narrower and include a second set of the LE14H-3s, flared ports, and recessed waveguide and woofers.

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penngray said:
Any discussion in this thread wrt screw on vs bolt on and if the "tube" section of the screw on causes audible issues?

Are all the Econo-wave projects using the "screw on" version?
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Here, the wave guide itself is screw on. so if ou get the bolt on compression driver, you'll need an adaptor, which may cause the trouble your talking about. There is some discussion about adaptors and the B&C DE 250, which is a bolt on, which requires an adaptor. I wouldnt worry about it.

Russellc
 
jackgiff said:
Thanks, Ross. That is a very nice endorsement for the project. I had lots of fun, learned a lot, and bless Zilch's heart, he was quite instrumental in keeping my spirits from sagging via PM's a couple times. I learned to use an RTA, an electronic crossover, and was introduced to the writings of several noted speaker designers like d'Apollito and Dickason, and watched as Wayne Parham became involved in the thread. Pretty heady stuff for a newbie.

I wish I had my mobile test stand when the development was being done. I can't count the times I carried circuits back into the lab to change parts, or work on new concepts. Or the number of times I took the soldering iron out into the garage to do something.

I recently bought an oscilloscope to complete my rack mount test station, and while looking for a shelf to rack mount it, discovered a Tektronix R453 scope, already rack mounted. Bought it for my offer of $100. Now the station is complete. Can't wait to get to the next test session.

Now all it needs is a sink. :yes:
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I think I see a Nikko pre amp in that stack, identical to my very first "seperate preamp" :D

Russellc
 
Pio1980 said:
Did the measurements include polarized pulse testing to check acoustic polarity and time/phase alignment?

Doing some preliminary experiments with one AR-6, it's x'over, and a JBL 6X6/ D210Ti combo tells me that the WG driver "wants" to be mounted appx'ly on the back of the baffle board to blend the mid's plane with the woof's to bring the midrange "into focus" when auditioned on axis. This could be a deal breaker mounting the 6X6 WG to the B/B, I don't see how the EW x'over could change that.
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How did your 6x6 JBL and 210 tell you this? Mine wont say anything, dammit!:D

Russellc
 
GordonW said:
I've taken to making my own woofer variants.

JBL M115-8A PA woofer frames (oftentimes found as blown speakers, cheap, in online auctions), reconed with the following parts (available from any speaker reconing shop that gets parts from MWA Speaker Parts Inc.):

Voice coil: 1565-8 (the "standard" coil used in the M115, in an aftermarket recone)

Cone: 451561-8 (Eminence 15" cone, bell shaped, smooth texture)

Spider: CS5745-B or CS5755B or CS-5760B (spider inner hole on any of these will have to be cut out to fit over 2.5" voice coil in speaker, as they are originally made to fit smaller voice coils)

Dustcap: DCF4500 (4.5" felt, lip-up)

When this speaker is built up, the fabric surround should be sealed/coated with Waldom AA-75 damper "dope"... this will maintain flexibility of the surround and damp "bell modes" in the cone, as well.

This combo will give a speaker that's flat up to 1500 Hz. Very high efficiency (like 96dB). I tend to use them in pairs per cabinet, in a 2.5-way alignment... the second woofer is crossed over at around 70-80 Hz, so it ONLY does bass, while the first woofer goes all the way up to meet the E-wave horn in the mids. With two of these in an 8 cubic foot cabinet, tuned to 22 Hz or so, it's flat to 30 Hz, maybe lower, especially in-room.

Yes, I know this is a bit elaborate for most people... but if you're industrious, it makes for an EXTREMELY potent, fast, clean woofer system...

Regards,
Gordon.
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Gordon, thats outstanding! Have you ever done a thread on that?
I basically understand everything you said, but seeing it would be excellent.

I've been thinking of running the Dayton 10"/$25 woofers @4 a channel. 2 choked, two open, and2 ported and 2 sealed. At least until I saw you're post ,bet they sound great.
 
What do you guys typically put in your enclosure for fill or on the walls? In the past I have used egg crate foam in ported subs and polyfill for sealed ones.
 
Plain old itchy fiberglass? I have read that it can blow out of the ports for a little while just after finishing the speakers. How do you attach it to the walls? Staples or 3M spray adhesive?
 
Yeah, that.

Plastic head (~1" square) ring-shank roofing nails look like they'll work nicely, but I confess I've never tried them. Replace the nails with sheetrock screws of the appropriate length, if you're squeamish. High density fiberglass (R-15) is better and easier to work with than R-13. Your local upscale gourmet lumber yard will have it, or be able to get it for you. Purchase unfaced bats or rolled, if available.... :yes:
 
If you are worried about the itchy stuff entering the air, cover the inside of your port (if you use one) with some of your wife's nylons.
 
golana: I used the 10" Daytons in my KLH-17 upgrade project detailed HERE. They are awesome!

tsloms: If you're worried about fiberglass fibers in the air from a ported design, use Acousta-Stuf. I did, in the project linked above. 2 pounds per cubic foot.
 
Russellc said:
Here, the wave guide itself is screw on. so if ou get the bolt on compression driver, you'll need an adaptor, which may cause the trouble your talking about. There is some discussion about adaptors and the B&C DE 250, which is a bolt on, which requires an adaptor. I wouldnt worry about it.

Russellc
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Thanks Russel and Zilch,

I did explain my question well enough.

I want to understand the preformance differences between screw on waveguides vs bolt on waveguides. I have read that the screw on waveguide design have a longer tube like throat that possibly causes problems vs the bolt on waveguides that have additional no tube like throats.
 
There is no way to know that, as the waveguide only comes in one version; it's throat adapter or none, conceptually, and I have provided that data....
 
I have read that the screw on waveguide design have a longer tube like throat that possibly causes problems vs the bolt on waveguides that have additional no tube like throats.
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Sounds like you are talking about a throatless driver vs a throated one. The larger 1.5" JBL drivers are throatless so when you mount them up on the waveguide the phase plug is clearly visible just below the screen. With a throated driver you look down a tube and at the bottom is the screen with the phase plug behind it. On the threaded drivers they all have throats, that's what's threaded. The throatless drivers are the more modern designs and having no throat has it's advantages.

That said I would not make a decission on which driver to use based on if it has a throat or not. All of the vintage drivers and many modern ones have throats. So even if an older driver that has a bolt on flange still has a throat. Both types can sound great if they are set-up properly.

Rob:)
 
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For $40 it works really well, dispite having a throat! Seriously, going to a 1.5" JBL is, what, 5x the cost? 10x? We've got to keep in mind that the driver and waveguide cost less than many dome tweeters! :thmbsp:
 
Zilch said:
High density fiberglass (R-15) is better and easier to work with than R-13. Your local upscale gourmet lumber yard will have it, or be able to get it for you. Purchase unfaced bats or rolled, if available.... :yes:
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Is there a down side to using faced insulation? It seems the faced stuff would be easier to tack in, but I wonder about the potential for paper "slapping" the cabinet walls during high-energy passages.
 
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