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Zilch's AK Design Collaborative - Econowave Speaker

Jcricket said:
Do those actually get down to the 30hz?
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They do, indeed.

Run the box models; woofer Fs is 28 Hz.

Jcricket said:
Parts list?
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I just started optimizing the crossover last night. Thus far, I confim Jack's earlier findings; the drivers are running in phase (inverse of eWave standard), and the forward axis is just above the waveguide.

The objective is a slam-dunk, build-from-scratch, kick-ass EconoWave kit, and this combo holds that promise.

Clmrt said:
I've read that it is absolutely necessary to flush-mount the WG in the baffle. I've also read the the WG forces the sound out from the baffle in such a way that flush mounting and BSC is unnecessary.
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Constant directivity waveguides render flush mounting and cabinet roundovers moot, as the edges are only minimally illuminated:

http://techtalk.parts-express.com/showthread.php?t=214805

It is largely an aesthetic issue, and that applies to woofers as well.

In this respect, waveguides afford substantial improvement over traditional tweeters in vintage cabinets having recessed baffles and abrupt edges.

Baffle step, the transition between 2-Pi and 4-Pi loading in freefield deployments and occurring at lower frequencies where the waveguide is not involved, remains a factor in design.... :yes:
 
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Zilch said:
Edit: Back to basics, now:

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Standard eWave w/DC300-8 front-mounted in 30 Hz vented KDT, ~$400 a pair the complete kit.... :yes:
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Very cool!
 
Zilch, I do agree that the horns should minimize diffraction problems as compared to domes and such. However, some people go to great lengths to avoid sharp edges even on the back side of a cabinet because of supposed negative audible effects. Have you ever compared the same components in different cabinets to see if audible effects existed?
 
dnewma04 said:
Have you ever compared the same components in different cabinets to see if audible effects existed?
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Wayne built Pi-Speaker cabs (I forget which model) with and without roundovers (they were initially made with them), and though differences were measurable, they were not audible.

We're in a good position to make that assessment with these KDT cabs. I stuck the foam on the "lips" here (which are a substantial 1.15" deep), and there are measurable differences, posted some pages back, but they are insubstantial. It may be argued that the effects are still there and we're only seeing the signature of the foam overhang rather than the wood one, but we're in a good position to refine the determination via moving the baffle forward incrementally, and ultimately, rounding over the edges.

Jack and Skywave have already built with the baffle flush front in order to capture more cabinet volume, and I'll be moving the baffle forward to find out more about edge diffraction effects, once I establish a stable system to test. EWave has been subjected to some ridicule on other sites for ignoring these factors in vintage cabs and the KDTs, but evidence is mounting that those concerns are unwarranted. Despite the big deal made of this, nobody has yet presented data substantiating that Linkwitz et al. have it wrong. I'd like for it not to matter, of course.... ;)
 
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Zilch said:
I just started optimizing the crossover last night. Thus far, I confim Jack's earlier findings; the drivers are running in phase (inverse of eWave standard), and the forward axis is just above the waveguide.
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Zilch, are you talking about the xover in box posted in post 9217 that you described as "standard eWave"? So what's different that allows the drivers to run in phase, just a new xover design? Will this new xover effectively make the first post linked ones obselete?
 
cubby01 said:
Zilch, are you talking about the xover in box posted in post 9217 that you described as "standard eWave"? So what's different that allows the drivers to run in phase, just a new xover design? Will this new xover effectively make the first post linked ones obselete?
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No, don't leap to conclusions here. We're using better tools and deeper understanding two years later, is all. In detail, each project is different, and DC300 has already been found by several of us to be, well, "challenging" in the eWave context.... :rolleyes:
 
Gotcha! So I'll carry on with my current build plans assuming PE doesn't run out of the Jan 22nd inventory before my order gets filled. :thmbsp:
 
Woohoo. I just popped over to PE and my shopping cart said the waveguides were in stock so I went ahead and completed my order.
 
KD Trapezoids w/DC300-8

Compare actual measurement of DC300-8 in this cab to the factory curve here:

http://www.parts-express.com/pdf/295-320s.pdf

Kiss 3-4 dB goodbye flattening it:

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First shot with standard eWaveguide and D220Ti buries the PRX @ +/- 1.5 dB, and the filters align textbook:

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Crossover frequency and foward axis are both too high, but we've been here before.... ;)
 

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Bad ideas from good people

Zilch said:
EWave has been subjected to some ridicule on other sites for ignoring these factors in vintage cabs and the KDTs, but evidence is mounting that those concerns are unwarranted.
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Simple, inexpensive, and effective. Clearly we have lost our collective minds thinking these three words can be strung together in the audio world.:thumbsdn:

Which brings me to my project...this can't sound good...Emminence Kappalite 3015 in 5 ft^3 box with standard eWave horn and driver. One side has the standard high efficiency crossover and the other has the LE14 variant (with reversed woofer polarity!). The 3015 is rated for 100 dB efficiency and they really are loud :music:

Then I had to make them fit in my entertainment center....which took some work....and committed the cardinal sin of putting speakers into furniture.:nono:

True RTA and a testing mic was found under the Christmas tree this year so I'll have some testing to do to show just how bad it is. Of course I think it sounds pretty good but what would I know...I've been listening to pair of L100 for 20 years. :D

The open space under the TV will get a center channel. Deltalite II 2510 is what I have to play with.
 

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Zilch said:
PRX is the JBL horn from MRX/PRX series.


The curves are of a JBL 123A-1 (L100) woofer with that combination using the D220Ti compression driver and an eWave crossover, some component values adjusted, left:

[
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Zilch: Pretty impressive curves. :banana:

Could you please expand on the "some component values adjusted"

Thanks

SheldonD
 
Don, the speakers in the furniture look, well custom. :thmbsp: Where did you buy the port tubes and what size are they?
 
Zilch said:
Compare actual measurement of DC300-8 in this cab to the factory curve here:

http://www.parts-express.com/pdf/295-320s.pdf

Kiss 3-4 dB goodbye flattening it:
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Sounds like the woofer definitively needs a larger box, to stop the roll-down below 300 Hz.

I'd like to see a similar plot of the DC300 in three cubic feet, again tuned to around 29-30 Hz (maybe even as high as 32-33 Hz)... I'd bet the low end response will pop up a number of dB (requiring MUCH less compensation in the mids). I can at least give pretty definitive anecdotal evidence that the DC300 DOES have PLENTY of midbass and bottom end in such an enclosure...

In essence, you can't fight Hoffman... bass response in small box = low efficiency.

Regards,
Gordon.
 
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I searched the thread and found one other time this question was asked - no answer. I'll ask again and see if anyone know's
I am looking at this horn from Pyle - a constant radiation horn. Here is the PE link. ANy thoghts or axperience with this horn?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2576


I am working on my Barzilays - electrically speaking they are excellent. Mechanically, well, hmm.

I am thinking it might be better to scratch build a set of cabinets. The barzilays are beautiful, but I think I am going to have to put so much reinforcement and bracing that it might be easiser to start over.

Thus, I might change to this horn.
Just a thought.
 

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Here is a crazy thought.
What if I used two horns/drivers per speaker using the 16 ohm drivers in parallel. Any benefit? Probably just a really good way to complicte and screw up everything - but you don't know if you don't ask.
 
You want to parallel 16 horn and have two horns per box ??? I'm no expert but I think your assumption is right about screwing things up. You end up with multiple origination points for the same sounds. The identical waves from two source points combine creating lots of potential for the sound wave interference**. The interference is more evident to the listener in the higher frequencies. This is one of the reasons you build crossovers to keep overlap to a minimum. You want sound for a given high frequency range emitting from a single point per channel if possible.

** see http://www.sfu.ca/sonic-studio/handbook/Interference.html

Edit:
Just found this. It's an absolutely cool little Java applet that visually demonstrates the effect of point separation at different frequencies.
http://www.google.com/url?sa=t&sour...K2Xe9wYIo7ST8X-rg&sig2=RgISE4EXLbN24OoeU5TC5g
 
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I thought it might be a "cosmetically" itriguing thing. I also thought if I did it and mounted the horns on a 30 degree angle pointing outwards, rather pointing straight, it might give even more dispersion. But, like I said, I am good at screwing things up.
 
donprice said:
Then I had to make them fit in my entertainment center....which took some work....and committed the cardinal sin of putting speakers into furniture.:nono:
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I'm coming down there to kick your butt!

[When's the game on? :D ]

Jcricket said:
Here is the PE link. ANy thoughts or experience with this horn?
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Nothing 'til I get a pair.

Jcricket said:
What if I used two horns/drivers per speaker using the 16 ohm drivers in parallel. Any benefit? Probably just a really good way to complicte and screw up everything - but you don't know if you don't ask.
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It's axiomatic: Multiple sources playing the same program concurrently in a common acoustic space will interfere with each other in a complex manner which varies with the differential distance(s) to those sources. :yes:

Jcricket said:
I thought it might be a "cosmetically" itriguing thing. I also thought if I did it and mounted the horns on a 30 degree angle pointing outwards, rather pointing straight, it might give even more dispersion.
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That'll work if you get the angles right, but to what purpose? Max dispersion (omni) has limited applicability.... :dunno:
 
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