Zilch's AK Design Collaborative - Econowave Speaker

[Wayne Parham]

The issue with the QSC waveguide is its depth, and how that affects system time alignment in comparison to the standard eWave. Given the added costs of using DE250 to build a "Deluxe" version, we're giving the design additional scrutiny.
...
The standard eWave crossover is one capacitor and a Zobel away from Wayne's 3-Pi crossover design, which Skywave is trying:

http://audioroundtable.com/forum/index.php?t=msg&&th=12067

Jumper J3 on the eWave PC board provides the insert point for the additional capacitor (C3 in Wayne's schematic) to convert the eWave highpass to 3rd order (or 4th order, if the HF comp capacitor C1 is considered a pole). Note that the HF driver connection is postive polarity.

See also:

http://audioroundtable.com/forum/index.php?t=msg&th=12232
...

Hope you don't mind my pasting my E-Mail reply to you in the ART thread (12232) above. Seemed like it might be useful. It says, in a nutshell, what I think you guys are dealing with. It's the normal stuff you have to juggle in a design like this, sometimes if things are too far off they're deal breakers and other times you can work with them. Just some quick notes on what to look for and how to identify what you're looking at.

I'd get more involved but zheeeesh, I'm busy these days. Have a hard time keeping up with my own stuff. Besides, I did a LOT of work designing my wood horn, and it's the shape I want. The H290 is pretty darn close, so I don't see spending a lot of time looking at other options.

You guys are starting to see how much work is involved to optimize a design and set the position of the lobes (and nulls) where you want them to be, so you can probably understand how I would be pressed for time to jump in on something new when I'm already pressed for time as it is. And like I said, this is a road I've already traveled, made my choices and designed for them.

On another subject, I think BiRadials usually have better pattern control than what we're calling waveguides these days - conicals, quadratics, oblate spheroidals and some radials. BiRadials and Manta Rays have diffraction slots to widen the pattern when beaming sets in because of throat diameter. They also use diffraction edges to set the pattern on the low end - the extra widened last third of the horn that prevents the pattern from narrowing just before it opens up on the bottom end from mouth diffraction. Those kinds of feature give better pattern control than horns with what I'd consider more "pure" contours lacking diffraction edges. But the disadvantages of a BiRadial or Manta Ray horn are that they suffer from astigmatism and response ripple. The diffraction edges that modify the pattern also make discontinuities that create impedance spikes and response ripple. These discontinuities are manifested in both the frequency and time domains, of course.

 

[Zilch]

Hope you don't mind my pasting my E-Mail reply to you in the ART thread (12232) above.

No problem, especially this:

Man, that WTPro ICD is really great for doing this. I got soooo spoiled with it. I used to wrack my brain trying to calculate the estimated phase to the Nth degree, using Hornresp to see the acoustic phase, combine that with electrical phase and baffle spacing and try to set the forward lobe that way. Then I'd model in Spice to get the electrical amplitude response and phase that I wanted and hope for the best. It was really hard work, and frankly isn't as accurate as just plugging in the numbers, building the crossover (in the ICD) and measuring the end result. Then when I build a physical model with caps and coils, it's right on the money. It is absolutely wonderful for this, and I honestly attribute it for why I'm able to get the results I get. Without it, you'd have to build a dozen physical models or more to dial it in, and you'd probaby give up and call it good after three or four, tops. But with the ICD, I can do a dozen in an hour, no sweat. Sweeeeeeet.

Santa may be leaving you a QSC "present" with which to demonstrate your mettle for the benefit of eWavers everywhere....

 

[Wayne Parham]

The Smith & Larson WTPro really is a great system, and the ICD is an excellent crossover development tool, especially if you're proficient with Spice. I had been using Spice to model my crossovers for years, and was able to use my existing Spice models in the ICD when it was introduced. It really does make it easy to test and try new crossover configurations and you literally can do a dozen in an hour with it. You'll spend more time setting up and taking down than you will testing. That's the way it should be - spend all your time in preparation and the actual test takes just an instant.

By the way, don't confuse the S&L WTPro with the Parts Express WT3. Smith & Larson are the original designers and they provide ongoing support and development. The WT3 is a knock off and doesn't do nearly as much as the S&L systems. I understand the PE device isn't as accurate either because when they copied an early model of the WT2, they even copied some of its bugs. Those have long since been corrected in the S&L systems.

 

[Steve O2]

Well I finished my 2nd pair of E wave's

I used these old CV 317 P 15" 3 ways I bought for $60.00. NICE real wood veneer cabinets with 2 Foster horns in front and one in the back.

They looked like good candidates for E waving...

Im using the Selenium D2500ti-nd with these, they are a little hot way up high with the standard E wave crossover but they sound better than the D220ti IMO

There is a brace in the cabinet right above the woofer. I would have like to have mounted the waveguide lower but the brace was in the way...

I had some trouble with a huge bump in the woofers response right around 1.2-1.6 KHz.

I went through my pile of old crossovers and ended up adding a 1.5 Mh in series with the .75 Mh coil on the 4 ohm high efficiency crossover...

This measured 2.2 Mh on the WT 3, it flattened it out perfect:yes:

I refoamed the original woofers and they sounded great... BUT at very high volume at 600 WPC they would occasionally bottom out:thumbsdn:

So I pulled the woofers from my RE 38's to try. These NEVER even come close to bottoming out. They have bumped back plates on the magnets.

They unfortunately have an even worse spike and now I have a small bump in response at around 1.2 KHz...

I can EQ it flat though with my DCX 2496.

The other woofers for some reason work great in the RE 38 cabinets, no bottoming out and great bass:scratch2: Must be the tuning of the cabinets...

Soo I guess Im not really done yet but I figured Id post some pics:thmbsp:

Im on the lookout for some of the cloth surround CV woofers or some of the AT 15 woofers with bigger vented magnets to try before I finish the crossover.

These things sound very nice right now though

 

[skywave-rider]

The Smith & Larson...

By the way, don't confuse the S&L WTPro with the Parts Express WT3. Smith & Larson are the original designers and they provide ongoing support and development. The WT3 is a knock off and doesn't do nearly as much as the S&L systems. I understand the PE device isn't as accurate either because when they copied an early model of the WT2, they even copied some of its bugs. Those have long since been corrected in the S&L systems.

I am attempting to get S&L WT2 to run on my MAC computer, and Keith Larson has personally been helping me out. Been making measurements at work on a PC with the system, but hopefully can get it to roll at home on my MAC laptop in the future. Not many software companies would help out a customer like this, IMHO.

SoundEasy never even returned one of my emails.

 

[skywave-rider]

...
Which BMS driver is it you use?

Russellc

I have BMS 4550s on an active system. Also 4552NDs which will go on my JBL 6x6 system.

...Has anyone just tried Wayne's HF from the 4Pi with the same driver? Just wondering, seems like maybe Skywave had a version with that circuit?

Russellc

Currently using that at home. But it's not plug and play. I used Wayne's attenuation/compensation chart and used max attenuation values (20dB IIRC) PLUS added an L-Pad. Level match is good for fairly inefficient JBL 123A1 woofers. But HF is overcompensated with QSC waveguide. I got it nearly flat by adding a notch which is centered above DE250 rolloff. That is not optimal of course, but it sounds damn good. I am still going to measure verticals on this.

 

[ROSSO]

...BiRadials and Manta Rays have diffraction slots to widen the pattern when beaming sets in because of throat diameter. They also use diffraction edges to set the pattern on the low end - the extra widened last third of the horn that prevents the pattern from narrowing just before it opens up on the bottom end from mouth diffraction. Those kinds of feature give better pattern control than horns with what I'd consider more "pure" contours lacking diffraction edges. But the disadvantages of a BiRadial or Manta Ray horn are that they suffer from astigmatism and response ripple. The diffraction edges that modify the pattern also make discontinuities that create impedance spikes and response ripple. These discontinuities are manifested in both the frequency and time domains, of course.

So, my (perhaps ignorant) interpretation is that the JBL 365124-001 8" x 8" waveguide, (120x60, $14 ea at JBL Pro, used in the AC18/26) looks to me like it matches Wayne's description? Anybody tried a test drive on these? Seems like all the other JBL WG's in the catalog have been tried at least once... (I know, I've asked this before, and yes, I have a pair.)

Hi Cody, Sounds like you have a full plate with all those projects. The Valencia's that have BMS drivers are one pair each of 4550 and 4552ND. The difference in sound is negligible. Both pairs are on Altec 811 horns. The Santana pair is 4550's on the JBL bolt on waveguide (Not Econo).

I e-mailed Assistance Audio for a price quote on BMS drivers of interest, and here is the answer:

Hello Jack,
Thanks for your interest in BMS.

4540 are $124 ea.
4550 are $147 ea.
4552 are $189 ea.

Regards, Jack Arnott
Assistance Audio

Think we have enough interest to put together a group buy?

 

[Zilch]

So, my (perhaps ignorant) interpretation is that the JBL 365124-001 8" x 8" waveguide, (120x60, $14 ea at JBL Pro, used in the AC18/26) looks to me like it matches Wayne's description? Anybody tried a test drive on these? Seems like all the other JBL WG's in the catalog have been tried at least once... (I know, I've asked this before, and yes, I have a pair.)

I eWaved Large Advents with the 90° x 50° version, and I believe Jack's using them in his surrounds, yet to debut complete here....

[Posted somewhere in this thread.... :yes: ]

 

[cubby01]

Was given a pair of these today with a blown mid. They are Pioneer CS-811A from mid '70s. According to a spec sheet pasted to the back they are 97db and freq resp of 30-22k but I kinda doubt both figures. Anyway they are fairly heavy cabs in pretty good shape and seem like maybe econowave fodder to me. I would need to put in new baffle (which may be difficult), but I can reuse the L-Pads, and some of the x-over parts, I saw there were a couple 1.5mH inductors in them, don't know what else.
..... Or is this idea just throwing good time and money away? Anyone had success with these old pioneer CS-series woofers? If I don't do these I will most likely end up doing my utility NLAs but I was wanting something a bit more effecient to use with tube amps.

btw-this pic isn't mine. A fellow AK member had linked to a pair in another thread sometime back and just borrowed the link. On my pair every darned one of the dust caps is pushed in. :sigh:

 

[Zilch]

There's just not a huge risk in eWaving anything due to its modular nature.

You can turn those upside-down, stick the waveguide on top, and connect the crossover to those woofers directly by bringing leads to them out the ports.

Once you determine whether you like how it all works together, you can decide to mod them, or not, on the basis of how they sound.... :yes:

 

[skywave-rider]

...

Think we have enough interest to put together a group buy?

For 4540s?
Let's see...with those, I could simply screw-on my 6x6 waveguides sans adapters....

Group buy, eh?

I might be in.

 

[ROSSO]

For 4540s?
Let's see...with those, I could simply screw-on my 6x6 waveguides sans adapters....

Group buy, eh?

I might be in.

I'm game for the 4540 bus too.

 

[Zilch]

Last group buy with Assistance was 15% off, minimum 10 pair, mixed OK.

4555 is the 1.5" BMS that bolts up to the full array of JBL PT waveguides, which are ~$100 each, the "Premium" combo Jack mentioned above.... :yes:

 

[juniorJBL]

Count me in!! :yes:

 

[Pio1980]

Finally got the Yamaha monitors moved off the stands and the Advent/2 min-E-Waves up and running in. First impressions are that they punch and sound bigger than they are. Oh, and they don't suck.:thmbsp:
I'll run them in with the Yamaha CR-1040 and get some long-term listening impressions.

 

[ROSSO]

If anyone knows how to parse this back into an Excel table, feel free.

BMS INFO:



EDIT: not perfect, but better...

 

[Wayne Parham]

So, my (perhaps ignorant) interpretation is that the JBL 365124-001 8" x 8" waveguide, (120x60, $14 ea at JBL Pro, used in the AC18/26) looks to me like it matches Wayne's description?

BiRadials and Mantarays are usually called by name because they're registered trademarks, not just descriptions of a flare shape.

The main feature(s) are the diffraction edges. You'll see a sharp-edged diffraction slot in the throat and in the case of the Altec Mantaray and Electro-Voice constant directivity horns (as well as others), you'll see a sharp-edged transition about 1/3 back from the mouth, where the flare rate gets suddenly wider.

Again, these kinds of horns trade sound quality for pattern control. Those sharp edges create discontinuities which are reflected back as impedance and response spikes. Get rid of the sharp edges and the sound is smoother, but you can't get quite the same pattern control at frequency extremes.

When you see horns described as "waveguides", they're definitely not BiRadial or Mantaray horns. Sometimes you'll see a horn advertised as CD but notice it has no sharp edges inside - Same thing as a waveguide. These are horns having quadratic, conical or oblate spherioidal profiles (if axisymmetrical), or radial horns having quadratic, catenary or conical flares (if asymmetrical). Another horn of this type is the prolate spheroidal or eliptical, which is similar to a radial horn. Each of these have smooth contours and provide CD through most of the passband. Their response is smoother and sound quality is better than diffraction (sharp-edged) horns, in my opinion.

I am attempting to get S&L WT2 to run on my MAC computer, and Keith Larson has personally been helping me out. Been making measurements at work on a PC with the system, but hopefully can get it to roll at home on my MAC laptop in the future. Not many software companies would help out a customer like this, IMHO.

Keith is a really great guy, isn't he? I consider him to be a personal friend and it sounds like you do too.

If you can get to the Lone Star Audiofest, he usually does a seminar, as do I. If not, you might go back through coverage of previous shows because there are audio recording WAV files, handout documents and slide shows from the various seminars.

 

[Pio1980]

Was given a pair of these today with a blown mid. They are Pioneer CS-811A from mid '70s. According to a spec sheet pasted to the back they are 97db and freq resp of 30-22k but I kinda doubt both figures. Anyway they are fairly heavy cabs in pretty good shape and seem like maybe econowave fodder to me. I would need to put in new baffle (which may be difficult), but I can reuse the L-Pads, and some of the x-over parts, I saw there were a couple 1.5mH inductors in them, don't know what else.
..... Or is this idea just throwing good time and money away? Anyone had success with these old pioneer CS-series woofers? If I don't do these I will most likely end up doing my utility NLAs but I was wanting something a bit more effecient to use with tube amps.

btw-this pic isn't mine. A fellow AK member had linked to a pair in another thread sometime back and just borrowed the link. On my pair every darned one of the dust caps is pushed in. :sigh:

Looks like any number of "Kabuki" speakers I've seen at Army PX/Audio Clubs in the '70s noted for producing tons of shrieking midrange. They aren't good for much stock if that sound isn't your cuppa. E-waving with the stock woof could be a problem if it wasn't designed to produce lower mids to, say 1800-2kc. If the boxes are heavy and solid they could get the new baffles with a Dayton woofer that will cover the lower mids for E-W'ing. Correct porting will keep your efficiency up.

 

[Bauhausler]

False alarm

A box was here waiting for me. I thought it would be the QSC waveguides. It was only half of an Ampzilla, which I had forgotten I had ordered.
Waiting with bated breath...

 

[cubby01]

Looks like any number of "Kabuki" speakers I've seen at Army PX/Audio Clubs in the '70s noted for producing tons of shrieking midrange. They aren't good for much stock if that sound isn't your cuppa. E-waving with the stock woof could be a problem if it wasn't designed to produce lower mids to, say 1800-2kc. If the boxes are heavy and solid they could get the new baffles with a Dayton woofer that will cover the lower mids for E-W'ing. Correct porting will keep your efficiency up.

Yeppers, I don't care much for the kabuki thousand points of sound myself. After looking at the spec sheet the existing crossover appears to be at 1.3kc so we'll just have to play with it and see.