Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
skywave-rider
Slumming in Akihabara
It's hard to keep up with this thread. Since I am using 123A-1 woofers I felt I should chime in a little, but had to review some old stuff, return back to the top, low and behold, a dozen new posts to read.
Here's where I'm at with L100 woofers:
-Determined vertical spacing options for Econo x-over (1.6kHz) options:
12" = 41 degrees null angle
11" = 45 degrees " "
10" = 50 degrees " "
From the best we've been able to determine, the Econo PT waveguide shows about 50 deg vertical dispersion at 1.6k. No one here has measured, Zilch slap me if I'm wrong. I intend to try to see the nulls when set up with new laptop and SoundEasy, or similar.
My 123A-1s do not sound distorted. They provide fairly flat, slightly boomy bass in a 2.3 cu ft sealed box with heavy fill. That's my dumpster bin, I did not make anything from scratch.
I built Econo x-over version designed for the least efficient woofers and found my L-Pads are within the first third of operational range, meaning the woofers are not optimally matched in efficiency, but close enough.
The big issue I need to resolve is driver alignment. When early on I used the Altec Alignment method,
http://www.audiokarma.org/forums/showpost.php?p=1913628&postcount=438
I found moving the Waveguide forward filled in a gap in the crossover region. I feel this is the last issue I need to resolve.
I think the best way to do that is finally do what I've been saying for weeks, make woofer only baffles, freeing the waveguide, and find exactly where it works. W. Parham said somewhere along the line that once the delay is determined, crossover experimentation with different filters can compensate for phase alignment problems. The physical depth of the 123A-1 is very shallow, and you would think that would point the forward axis very high. If you are sitting in front of the speaker, you might well be in a deep null at 1.6kHz, or thereabouts. Zilch posits there is an electro/mechanical delay which mitigates the alignment problem. These are the issues I have using this woofer so far.
I hope I could simply move the EWG forward and leave it tweaked like that. Any issues with doing this? Reflections from the woofer hitting the back of the EWG?
I find the bass real nice from these, so I think it's worth pursuing. Maybe you guys who had problems with the woofer might check into some of these issues, of course first determining whether or not it's defective takes priority.
Re: the RTA, I think it's essential. It's been "instrumental," and I'm happy with the DEQ2496. Being a MAC guy, it was the cheapest way for me to go initially. None of the software based programs work on a MAC.
As I'm sure you know, room effects loom large in RTA measurements. I was always aware of room's influences, however this awareness is sharpened since using RTA.
It would be great to compare notes on EWG and 123A-1.
Here's where I'm at with L100 woofers:
-Determined vertical spacing options for Econo x-over (1.6kHz) options:
12" = 41 degrees null angle
11" = 45 degrees " "
10" = 50 degrees " "
From the best we've been able to determine, the Econo PT waveguide shows about 50 deg vertical dispersion at 1.6k. No one here has measured, Zilch slap me if I'm wrong. I intend to try to see the nulls when set up with new laptop and SoundEasy, or similar.
My 123A-1s do not sound distorted. They provide fairly flat, slightly boomy bass in a 2.3 cu ft sealed box with heavy fill. That's my dumpster bin, I did not make anything from scratch.
I built Econo x-over version designed for the least efficient woofers and found my L-Pads are within the first third of operational range, meaning the woofers are not optimally matched in efficiency, but close enough.
The big issue I need to resolve is driver alignment. When early on I used the Altec Alignment method,
http://www.audiokarma.org/forums/showpost.php?p=1913628&postcount=438
I found moving the Waveguide forward filled in a gap in the crossover region. I feel this is the last issue I need to resolve.
I think the best way to do that is finally do what I've been saying for weeks, make woofer only baffles, freeing the waveguide, and find exactly where it works. W. Parham said somewhere along the line that once the delay is determined, crossover experimentation with different filters can compensate for phase alignment problems. The physical depth of the 123A-1 is very shallow, and you would think that would point the forward axis very high. If you are sitting in front of the speaker, you might well be in a deep null at 1.6kHz, or thereabouts. Zilch posits there is an electro/mechanical delay which mitigates the alignment problem. These are the issues I have using this woofer so far.
I hope I could simply move the EWG forward and leave it tweaked like that. Any issues with doing this? Reflections from the woofer hitting the back of the EWG?
I find the bass real nice from these, so I think it's worth pursuing. Maybe you guys who had problems with the woofer might check into some of these issues, of course first determining whether or not it's defective takes priority.
Re: the RTA, I think it's essential. It's been "instrumental," and I'm happy with the DEQ2496. Being a MAC guy, it was the cheapest way for me to go initially. None of the software based programs work on a MAC.
As I'm sure you know, room effects loom large in RTA measurements. I was always aware of room's influences, however this awareness is sharpened since using RTA.
It would be great to compare notes on EWG and 123A-1.
OK, Speaker Worksop is installed on the Dell and the soundcard looks to pass muster. Do I need TrueRTA to analyze output or can I get crude readings with Speaker Workshop and a crappy computer mic?
I've never measured the nulls, no, but I'll be doing more with E'Wave and 123A-1s in the coming weeks here.
In the first iteration in C36 cabinets, Mxlews and I wrestled with the time alignment. In recognition of the shallow depth of the woofers, I assumed mounting them on the rear of the baffle would provide optimum alignment.
CLIO told us I was wrong, and we moved them to the front. I concluded that the mass of the heavily Aquaplas'd woofer cone moved the acoustic center behind the voice coil due to increased mechanical response time. That's speculation, of course.
This was pre-E'Wave crossovers, but the ones I have on them are externial, and I can take a fresh look at that, also. The HF drivers are BMS; I'll swap in Seleniums for comparison testing.... :thmbsp:
skywave-rider
Slumming in Akihabara
And riding a motorcycle....judging from the typing.
Please let me know about the software when ur safe...
skywave-rider
Slumming in Akihabara
I am having new woof only baffles requisitioned. Question; do you think I should have the woofers countersunk so as to be flush with the baffle? Or should I go easy and front mount?
dnewma04
The Healer
I take it you aren't using the fabled 9ac used to hack the ninex network in the glory days of hacking?
Just kidding. I did butcher that a bit, but then again I usually do even when sitting behind my computer's keyboard. There is a software called macthescope that has 1/3 octave capabilities for basic RTA measurements. The free download allows you to measure but not save, but for our purposes that works. The full version is brutally expensive.
http://www.apple.com/downloads/macosx/audio/fuzzmeasurepro.html
Fuzzmeasure pro looks useful.
dnewma04
The Healer
Speaker workshop will do those measurements, as will True RTA, but no software will be able to make up for the crap that they call a computer Mic. At a min, you'll need a Behringer or DIY a panasonic capsule mic and a mic preamp.
Electrovoice EWG's
Another Michigan guy taking the EWG plunge. I dug my old Electrovoice speakers out of the attic to make the sacrifice. They are a 10 inch 2 way in a 1.5 cu. ft. sealed cabinet. They are still in fairly nice condition and sound okay after all these years. I think I bought them in 1975!
I think a JBL LE10A will make for a nice match here. Looks like it might work well in a sealed cabinet. Components assembeld and ready to install.
Another Michigan guy taking the EWG plunge. I dug my old Electrovoice speakers out of the attic to make the sacrifice. They are a 10 inch 2 way in a 1.5 cu. ft. sealed cabinet. They are still in fairly nice condition and sound okay after all these years. I think I bought them in 1975!
I think a JBL LE10A will make for a nice match here. Looks like it might work well in a sealed cabinet. Components assembeld and ready to install.
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Russellc
Addicted Member
Looks like there is just enough room to cut the wave guide into the front. I n the mean time I'd try flipping the box upside down to bring the woofer closer to the guide.
Seems like there are some threads here talking about driver spacing and nulls or something like this. Congrats, I'm sure you'll be pleased with the results.
Russellc
Electrovoice EWG
Here they are with the drivers installed. I only have a few hours of play on them and they are scary good already. I need some stands to get them off the floor before I can really judge them. I also need to restore the finish on the walnut veneer a bit and modify the grill covers for the waveguides.
My hat's off to those contributing to the design.
Here they are with the drivers installed. I only have a few hours of play on them and they are scary good already. I need some stands to get them off the floor before I can really judge them. I also need to restore the finish on the walnut veneer a bit and modify the grill covers for the waveguides.
My hat's off to those contributing to the design.
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skywave-rider
Slumming in Akihabara
That is my low pass as well, for the record. Obviously, pinched from you, Zilch.
BB6P says they'll work closed box, but only with severely derated power handling, Black. You start running out of cone excursion at 75 Hz.
Vented, they'll kick butt, Red, tuned to 36 Hz with two 2" ducts, 7" long. You'll have full power handling down to 34 Hz. Indeed, it DOES say 109 dB there on the max acoustic power curve (not shown.)
I damped them down a bit with heavy fill, Violet, 34.9 Hz, the same ducts, 6.56" long.
Verify you like the sound before cutting in either the waveguide or the vents. :yes:
Edit: Oops, the deed is done already....
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Zilch,
Thanks for the analysis of vented vs. sealed. I did a similar comarison with some other software. I was going to put the vents in from the start but decided to listen to them sealed for a while.
If I go with vents, can I add them above the waveguides on the front baffle or am I better to put them in the back? There's no room down low on the front.
Thanks for the analysis of vented vs. sealed. I did a similar comarison with some other software. I was going to put the vents in from the start but decided to listen to them sealed for a while.
If I go with vents, can I add them above the waveguides on the front baffle or am I better to put them in the back? There's no room down low on the front.
They'll work fine up top.
You build fast. Did all that while I was typing, didya?
:I'm bettin' those are sounding mightily good.... :thmbsp:
Thanks for the confirmation, Skywave. :yes:
It's wirenut madness around here; nothing's final 'til it's on a board, and even then, they're subject to subsequent tweakery....