Zilch's AK Design Collaborative - Econowave Speaker

[ROSSO]

http://www.audiokarma.org/forums/showthread.php?p=2867674#post2867674

...The primary variables are the center-to-center distance between the drivers and the frequency at crossover...

... how low can DE250 competently play on the QSC waveguide? Will the nulls at a lower crossover frequency effectively compensate for the consequential losses in vertical pattern control?

So as I sit with QSC wg's and DE250's figuratively in hand, if center-to-center is important, then smaller woofer would be better??? If you had LE10A, 127H-1, LE120-H1 and LE14A to choose from, which would you surmise might produce the best result? Front mount the wg and back mount the woofer and overlap the flanges?

 

[Russellc]

So as I sit with QSC wg's and DE250's figuratively in hand, if center-to-center is important, then smaller woofer would be better??? If you had LE10A, 127H-1, LE120-H1 and LE14A to choose from, which would you surmise might produce the best result? Front mount the wg and back mount the woofer and overlap the flanges?

It would seem that way. Plus, the smaller the woofer, the higher up it can go in frequency w/o its pattern narrowing.......I still like 15 inch drivers though, but I'm a hard head!:yes: Going to try (eventually) a 12 inch driver, the JBL 2213H...its go'in in a 2.5 to 3.0 cu ft sealed box.

For now, my QSC hang over the front edge of the box like the ones Zilch has been showing. Puts the drivers closer together AND should be helping in the area of delay as well?



Russellc

 

[Zilch]

So as I sit with QSC wg's and DE250's figuratively in hand, if center-to-center is important, then smaller woofer would be better??? If you had LE10A, 127H-1, LE120-H1 and LE14A to choose from, which would you surmise might produce the best result? Front mount the wg and back mount the woofer and overlap the flanges?

We are rear-mounting the woofer for a different reason, to better align the acoustic centers of the drivers. A consequence is the cutout comprises a diffraction edge, and Brandon is testing whether a roundover mitigates some of what that does to the response. It may be possible to incorporate about 1/2" of the waveguide flange into the roundover, if it is recessed flush; Jack's gonna try that, I believe. There may be multiple advantages to rear-mounting the woofer, yes.

The squircle frame woofers have a snugging advantage over round ones when surface mounted. Are there other means to deal with time-alignment? Yup.

Are we talking design deal-breakers here? Consider the locations of the driver acoustic centers and the center distance in Altec Model 19. We're trying to do better, is all.... :yes:

 

[Russellc]

As to the 20 degree lobe,
Have a look over on the HTguide forum, in the "mission possible" forum,
post #174 by Dennis H in the "Can you smell what Brando's cooking?' Thread.

Apparently, the lobe may be larger than 20 degrees......?

Russellc

 

[Zilch]

As to the 20 degree lobe,
Have a look over on the HTguide forum, in the "mission possible" forum,
post #174 by Dennis H in the "Can you smell what Brando's cooking?' Thread.

Apparently, the lobe may be larger than 20 degrees......?

Yes, the nulls define the full width of the lobe, but that's where there is total cancellation at the crossover frequency, a very deep notch, 40 dB or more down, clearly audible. As a design objective, we want those to be located in the region of, at, or just outside the waveguide vertical beamwidth to augment the vertical pattern control.

The question is how tall a vertical listening window within those limits is desired, and I have suggested -6 dB as an appropriate criterion, i.e., at what included angle above and below the forward axis is the notch 6 dB deep?

Dennis is calling out a "Sweet spot" of +/- 10°, but has not defined his criterion, that I've seen, but it's kinda difficult to keep up with the action on several forums concurrently....

 

[Russellc]

Dennis is calling out a "Sweet spot" of +/- 10°, but has not defined his criterion, that I've seen, but it's kinda difficult to keep up with the action on several forums concurrently....

Boy thats the truth! I'm on 6 at once, 4 of which are playing with the QSC and B&C drivers, and 2 others which give me ideas BESIDES these units, i.e. at least 1 maybe 2 tube amps, 1 SS amp are current build ideas. And I'm in the middle of putting together the final tidbits on a measuring setup, got the programs installed, got the Dayton mic from PE and so on. There's that learning curve going on at the same time, fortunately learning each of these helps with the other, as far as speaker building/measuring is concerned.

Plain grueling I Tell Ya!

Russellc

 

[skywave-rider]

I am using Fuzzmeasure, it's a swept sine wave system. I move the mic above and below axis. I am starting with on-tweeter axis as my assumed forward axis, but that may not be correct. You can quickly see the nulls impinge on x-o frequency response. I am not currently using a protractor as I am not posting vertical response data in degrees or anything. But it's easy to see the pattern between nulls is narrow.

You can hear it too, just remember were talking about frequencies in the crossover region. Send pink noise out of your laptop and move your head above and below and you may hear the difference. When you get your mic/pre setup you will see this easily.

How are you measuring this lobe?
Russellc

 

[corbu]

High Efficiency Econo-Wave

Hi,

I'm new to AK and the Econo-Wave thread. Heck, I'm new to audio as well.

I have a pair of low power SET amps (300B) and wonder if an econo-wave would work. I will not be able to bi-amp now. Does the concept make sense with flea (8-watt) amps?

If yes, any suggestions for vintage high efficiency speakers to use for the woofer & cabinet? Atlanta CL has a pair of Cornwalls for $100.

I'm also looking at a pair of Altec 19's but they are a bit of a $ stretch for me at the moment.

Many thanks to all,

MJ

P.S. Here's a photo of one of my mono blocks!

 

[Zilch]

I am using Fuzzmeasure, it's a swept sine wave system. I move the mic above and below axis. I am starting with on-tweeter axis as my assumed forward axis, but that may not be correct. You can quickly see the nulls impinge on x-o frequency response. I am not currently using a protractor as I am not posting vertical response data in degrees or anything. But it's easy to see the pattern between nulls is narrow.

Remember trig?

Find the forward axis and calculate the mic heights corresponding to +/- 5°. 10°, 15°, etc.. Adjacent side remains constant for tangent.

I have to reset my window for each measurement, as the time to the first reflection changes with mic height. The differences aren't huge, so I suppose I could just set it to minimum for the series.

I have a pair of low power SET amps (300B) and wonder if an econo-wave would work. I will not be able to bi-amp now. Does the concept make sense with flea (8-watt) amps?

Welcome Corbu! That is indeed a handsome monoblock. :yes:

eWave will mate with woofers having sensitivities as high as 100 dB, higher, if you're going to do baffle step compensation, so 8 watts is more than enough. Maybe others can suggest efficient woofers to try. For new ones, think "Eminence." :thmbsp:

 

[ROSSO]

Boy thats the truth! I'm on 6 at once, 4 of which are playing with the QSC and B&C drivers...Plain grueling I Tell Ya!...

Russellc

I share some of your pain. I'm only finding out about the other threads as the work there gets citation here. Perhaps for the reference value we can get links to the most appropriate related waveguide threads added to the official E-Wave Page 1 "SUPPLEMENTS" section? :yes:

 

[skywave-rider]

Remember trig?

Hahahahahahahahahahahahahahahahahahahaha....

Actually I never learned it.........

But I guess I can figure it out.

Changing the subject rapidly...an aside: moving stuff around, getting ready to change crossovers, I threw the DE250 onto the back of an 18Sound XT120 http://www.loudspeakersplus.com/html/18sound_horns.html using standard EWave x-o. Fun..

 

[djnagle]

Hi,

I'm new to AK and the Econo-Wave thread. Heck, I'm new to audio as well.

I have a pair of low power SET amps (300B) and wonder if an econo-wave would work. I will not be able to bi-amp now. Does the concept make sense with flea (8-watt) amps?

If yes, any suggestions for vintage high efficiency speakers to use for the woofer & cabinet? Atlanta CL has a pair of Cornwalls for $100.

I'm also looking at a pair of Altec 19's but they are a bit of a $ stretch for me at the moment.

Many thanks to all,

MJ

P.S. Here's a photo of one of my mono blocks!

Welcome MJ. I would snatch up the Cornnies and turn them or ewave them. If you turn them, you could get enough cash for really eff. drivers.

What is the driver tube on that amp?

 

[doucanoe]

I have been running mine with a pair of 2A3 monos.

RC

 

[Russellc]

I am using Fuzzmeasure, it's a swept sine wave system. I move the mic above and below axis. I am starting with on-tweeter axis as my assumed forward axis, but that may not be correct. You can quickly see the nulls impinge on x-o frequency response. I am not currently using a protractor as I am not posting vertical response data in degrees or anything. But it's easy to see the pattern between nulls is narrow.

You can hear it too, just remember were talking about frequencies in the crossover region. Send pink noise out of your laptop and move your head above and below and you may hear the difference. When you get your mic/pre setup you will see this easily.

Interesting Skywave, and thanks for the reply!:thmbsp: Hopefully soon I will actually be able to see this for myself.:yes:

Russellc

 

[Russellc]

I share some of your pain. I'm only finding out about the other threads as the work there gets citation here. Perhaps for the reference value we can get links to the most appropriate related waveguide threads added to the official E-Wave Page 1 "SUPPLEMENTS" section? :yes:

There are so many I dont know if that's possible! Lots of older material on Lansing heritage, most famous here would be Zilch's "Quick and Dirty" threads,and others like "4430 help" and many others, then the entire E'wave thread has tons of links to all kinds of things related to wave guides. You might be interested in various threads on the home theater forums, there will be waveguide threads there from time to time, Augerpro's being at the fore front currently, using the QSC wave guide. Also well known is the DIY audio forum,lots of heady wave guide discussion there. That's where the majority of the Geddes wave guide discussion and his results from testing Econowave early in the thread originated. Plus, many of these are sort of off topic, but are definately "related reading"......once you start reading one or two, they all seem to refer to other stuff and so on,next thing you know, you'll have more than you can keep up with! Econowave gets mentioned all sorts of places anymore!

Enjoy,

russellc

 

[Bauhausler]

*** big snip ***

Econowave gets mentioned all sorts of places anymore!

Enjoy,

russellc

You don't know the half of it. Econowave is shortly to be burned into the collective DIY consciousness forever.
That's a tease, and I aint sayin' any more.

 

[Bauhausler]

Hi,

I'm new to AK and the Econo-Wave thread. Heck, I'm new to audio as well.

I have a pair of low power SET amps (300B) and wonder if an econo-wave would work. I will not be able to bi-amp now. Does the concept make sense with flea (8-watt) amps?

If yes, any suggestions for vintage high efficiency speakers to use for the woofer & cabinet? Atlanta CL has a pair of Cornwalls for $100.

I'm also looking at a pair of Altec 19's but they are a bit of a $ stretch for me at the moment.

Many thanks to all,

MJ

P.S. Here's a photo of one of my mono blocks!

My last pair of Ewaved Advents, of moderate to low sensitivity, are being driven very well by Audio Note Quest 300B monos. I'm angling to get some PP Class A triodes on there as time allows.

 

[skywave-rider]

You don't know the half of it. Econowave is shortly to be burned into the collective DIY consciousness forever.
That's a tease, and I aint sayin' any more.

Oh no. Time to go back and edit misspellings and correct bad data.

 

[DENNYDOG]

I found some really cheap ($40!) Valencia cabinets void the drivers that I think will be a better match to my TL-1601's than my Barzilay cabinets would. They even fit up to the baffle boards. It looks like the box volume will be just about perfect.

I just need to figure out what I want to do with the top portion where the old horns used to go. Not sure if I want to mod the cabinets so much as to not make the mods irreversible.

 

[Russellc]

Oh no. Time to go back and edit misspellings and correct bad data.

Pending "Stickidom" maybe?

Russellc