Of note: Lattice phase equalization filter by Zobel:
http://en.wikipedia.org/wiki/Lattice_phase_equaliser
http://en.wikipedia.org/wiki/Lattice_phase_equaliser
Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
jackgiff
Well-Known Member
JBL 8" square waveguide revisited.
I designed the 8 inch square waveguide into a set of E'waves that are being built for my nephews son. These waveguides were tested some time ago, and found to be needing different HF compensation than the standard 6X12" or 6" square waveguides. I thought it would be good to try to compensate them again before looking up the previous test, and then the results could be compared.
I tried several ways to compensate the final drop off that starts about 14-15 KHz, but came up with nothing that worked as good as simply increasing the value of C3 to 1.5 uF. Then I looked up the previous test, which was on page 275, post #4112. Apparently I haven't learned anything since the previous test, cause that is exactly the same result when I tried to compensate them then.
The best compensation in each test was with C3 a 1.5 uF, which resulted in a drop of about 7 dB from 14 KHz to 20 KHz. It just doesn't want to get any better without using electronic EQ. But it does go to 20 KHz, which some of the newer upgrades being touted here cannot do. For instance the B&C DE250 drops off above about 16 KHz like a rock. And that is an upgrade.
Zilch wanted me to try his Advent E'Wave crossover values, which I did (post 4133), and found no difference using them. And increasing the value of C3 above 1.5 uF just begins to lift the entire HF range, killing the HF feedback compensation technique.
I think it sounds very good, and have also designed them into my rear HT speakers. If the DE 250 is an upgrade, the 8 inch square waveguide deserves to be an "offical" E'Wave part. I can't hear anything up there anyway. My vote is YES for making the 8 inch square JBL waveguide an "offical E'Wave part" when used with C3=1.5 uF.
I designed the 8 inch square waveguide into a set of E'waves that are being built for my nephews son. These waveguides were tested some time ago, and found to be needing different HF compensation than the standard 6X12" or 6" square waveguides. I thought it would be good to try to compensate them again before looking up the previous test, and then the results could be compared.
I tried several ways to compensate the final drop off that starts about 14-15 KHz, but came up with nothing that worked as good as simply increasing the value of C3 to 1.5 uF. Then I looked up the previous test, which was on page 275, post #4112. Apparently I haven't learned anything since the previous test, cause that is exactly the same result when I tried to compensate them then.
The best compensation in each test was with C3 a 1.5 uF, which resulted in a drop of about 7 dB from 14 KHz to 20 KHz. It just doesn't want to get any better without using electronic EQ. But it does go to 20 KHz, which some of the newer upgrades being touted here cannot do. For instance the B&C DE250 drops off above about 16 KHz like a rock. And that is an upgrade.
Zilch wanted me to try his Advent E'Wave crossover values, which I did (post 4133), and found no difference using them. And increasing the value of C3 above 1.5 uF just begins to lift the entire HF range, killing the HF feedback compensation technique.
I think it sounds very good, and have also designed them into my rear HT speakers. If the DE 250 is an upgrade, the 8 inch square waveguide deserves to be an "offical" E'Wave part. I can't hear anything up there anyway. My vote is YES for making the 8 inch square JBL waveguide an "offical E'Wave part" when used with C3=1.5 uF.
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similost
Rockin and Rollin....
I was just wondering if you could order with an open account and then they ship you the parts as soon as they get them in. I don't want to wait forever to get going on this project just because others beat me to any of them they get in.
I am so lost with all the filters, and crossovers and all that jazz.. I guess once I get the parts and get started, then start experimenting with my Behringer and figure out what it needs, then I'll try and figure out how to build a passive one..
I'd go active, but I don't want a stack of monoblocks sitting around my living room.. a pair is enough.
I am so lost with all the filters, and crossovers and all that jazz.. I guess once I get the parts and get started, then start experimenting with my Behringer and figure out what it needs, then I'll try and figure out how to build a passive one..
I'd go active, but I don't want a stack of monoblocks sitting around my living room.. a pair is enough.
Call in and find out. I think the number is in the link from the first page. I believe Diane is the nice order person you will speak with. California time,
wait til they wake up.
similost
Rockin and Rollin....
I talked to them today. They gave me a date to try back but no promises. They won't take your order then ship when they have them, you just gotta call at the right time and keep your fingers crossed. I have a feeling they'll get tired of hearing from me...
hhibrownsbac
Super Member
I would definitely check each week, as an example two weeks ago they told me the same waveguides wouldnt be in till after the 1st of the year, I tried everywhere to find a set elsewhere with no luck(damn things are impossible to find almost from anywhere else), and then figured Id give them a call a couple days ago and they had a set then. You just have to keep trying.
donprice
Wound up workin' at a gas station....
Becareful what you wish for. JBL Pro Parts did backorder some of the horns (6x12 and 6x6 waveguides) when I ordered a couple of months ago. I don't have an account. They didn't ship what was in stock, didn't tell me what was out of stock, and didn't ship the out of stock items when they were restocked even after telling me they would be shipped. Six weeks and 6-10 phone calls did get it worked out. At least they were really nice about the whole thing. I can't complain since these were the $6 and $10 waveguides and they shipped them cross-country Fedex overnight.
You might save yourself a ton of agony if you go with Wayne's 3Pi (or 4Pi?) design which is already optimized (IIRC) for the AE driver you wanted to use. Not sure if it will fit the box size you have in mind and it will be a different HF driver/horn, and you won't have the "fun" of working out a crossover design. I would probably be building one of Wayne's designs today had I found his site before ordering the drivers/parts to build 3 complete eWave boxes.
Back to building...
Russellc
Addicted Member
Agreed. Eventually Zilch will build with them I'm betting, Augerpro mentioned maybe, once "No Quarter" is finished (passive), he may build up a high price version using perhaps that bass driver and a Beyma compression driver. I keep hearing these are the "best" from people who's opinions I trust.
Wayne's paper where he "fit" the AE driver to the 3PI is very instructive. Apparently it is an easy driver to use, in his case all that was required was removing the zobel, as the driver had no need for it.
Russellc
similost
Rockin and Rollin....
There are a few reasons I want to go with the driver load I've been looking at instead of "making do". I've got a pair of speakers already I really love, and from all I hear, a pair of these waves will take that over the top.. SO, might as well go all out and shoot for the best using the best parts I can get.
One of the first reasons for the horn especially is because after looking at the curves that Zilch had of the 4555 driver on the JBL guide, I don't think I could find a flatter curve, with a more sensitive and higher wattage driver. It appears the BMS driver is kind of the best of all worlds. After talking to someone that is using that combination, I don't think I'd be happier with anything else..
As far as the AE driver, again, after talking with someone that has a pair, I am having a hard time believing that a LE14 will be as detailed at the AE sounds to be. It sounds like AE has taken some of the best ideas from some of the more prominent driver builders, and taken it a step further. The more I read about them, and hear comments from people and companies that are using them, they just sound like they are the cat's ass, and us cat people know how proud a cat is of it's ass..
Another reason I am leaning so hard with this driver load is because I've always kind of leaned more towards pro line speakers because of the sound of them. They just don't sound like regular consumer stuff. Take that as good or bad, but it's the sound coloring I've always leaned towards. No idea if the final result will be what I'm after, BUT, I figure if it's not, I can always sell the parts for very little loss. These parts seem to hold their value well.
Last reason is, these are all very sensitive parts, and high wattage.. and who doesn't like loud?... OK.. at least I do, and if it's gonna be loud, it's gotta be clean and detailed, and it appears what I'm looking at will be it..
The crossover is going to give me hell.. BUT, I am thinking that if I can use m active crossovers to figure out what will be the best sound to get, then hopefully then I can get someone to help me figure out what parts I would need for a passive.. I figure that will be the easy part, but the hard part will be looking for the right point to cross them at, and how to damp the horn if needed since it's a LOT more sensitive than the woofer..
BUT, I may be totally WAY off base here, but hey.. if someone has to learn the hard way, it's gonna be me
One of the first reasons for the horn especially is because after looking at the curves that Zilch had of the 4555 driver on the JBL guide, I don't think I could find a flatter curve, with a more sensitive and higher wattage driver. It appears the BMS driver is kind of the best of all worlds. After talking to someone that is using that combination, I don't think I'd be happier with anything else..
As far as the AE driver, again, after talking with someone that has a pair, I am having a hard time believing that a LE14 will be as detailed at the AE sounds to be. It sounds like AE has taken some of the best ideas from some of the more prominent driver builders, and taken it a step further. The more I read about them, and hear comments from people and companies that are using them, they just sound like they are the cat's ass, and us cat people know how proud a cat is of it's ass..
Another reason I am leaning so hard with this driver load is because I've always kind of leaned more towards pro line speakers because of the sound of them. They just don't sound like regular consumer stuff. Take that as good or bad, but it's the sound coloring I've always leaned towards. No idea if the final result will be what I'm after, BUT, I figure if it's not, I can always sell the parts for very little loss. These parts seem to hold their value well.
Last reason is, these are all very sensitive parts, and high wattage.. and who doesn't like loud?... OK.. at least I do, and if it's gonna be loud, it's gotta be clean and detailed, and it appears what I'm looking at will be it..
The crossover is going to give me hell.. BUT, I am thinking that if I can use m active crossovers to figure out what will be the best sound to get, then hopefully then I can get someone to help me figure out what parts I would need for a passive.. I figure that will be the easy part, but the hard part will be looking for the right point to cross them at, and how to damp the horn if needed since it's a LOT more sensitive than the woofer..
BUT, I may be totally WAY off base here, but hey.. if someone has to learn the hard way, it's gonna be me
Similost,
I encourage you to go for your high end design. Anything less will leave you wondering if it could be improved and you would likely upgrade eventually. All you are missing is an optimized crossover. As Zilch suggested, you can start with his modified M19 design which I believe is the one attached (please correct me if wrong). Or, do the active crossover as long as it has CD horn compensation built in. I think I'm going to order a pair of the BMS 4555 drivers too.
I encourage you to go for your high end design. Anything less will leave you wondering if it could be improved and you would likely upgrade eventually. All you are missing is an optimized crossover. As Zilch suggested, you can start with his modified M19 design which I believe is the one attached (please correct me if wrong). Or, do the active crossover as long as it has CD horn compensation built in. I think I'm going to order a pair of the BMS 4555 drivers too.
Attachments
greenboy
UNMUTUAL
The JBL mini waveguides are the JBL PT-B99HF-1 (part number 364914-001) 6" x 6" ones I recommend in most of my designs. I like the wider 90° x 90° pattern for backline and close stage monitoring. Way better than they have any right to be, and perhaps the closest match to the original Econowave waveguide, the one that's in your megacab.
greenboy
UNMUTUAL
Might look at BMS drivers on that 6" x 6" JBL guide before adding ribbons or supertweeters.
Don't have the links handy right now, but in the event you need resonance damping there are a couple of specialty spray-on products and a self-adhesive damping sheet that's backed by foil, which really adds rigidity.
Merry Xmas to Zilch and Jack and all the e-wavers!
juniorJBL
SUB 1500 :)
Duffinator
Spin The Black Circle
Don't forget the 4425. :yes:Think 4430, 4435!
Wayne Parham
Active Member
Thanks for the kind words. Yeah, the process is simple in principle but time consuming to get everything right. And when I first started building speakers like these (in the 1970's), there were no models to draw from to start with. After looking at it from a few dozen different angles, seeing all the CD EQ schemes that had multiple filter elements, I finally settled on the R1/R2/C1 topology most of us now use. It also took some time to find a set of core splitter filters that seem to always work with a little tweaking. What once took hundreds of hours now takes tens, but that's still not a trivial effort. If you want 'em right, you have to do your homework.
By the way, the three Pi uses the TD12S, DE250 and H290 and the four Pi uses the 2226H, DE250 and H290. Crossovers are similar but not the same.
Basically, that's true although the low-pass filter also uses different components to get phase right. That's what really matters when setting the position of the forward lobe and vertical nulls. The value of C4 in the core splitter filter is different depending on the woofer chosen, as well as the insertion or deletion of the Zobel also depends on the woofer. One would expect the Zobel value might change when going to a different woofer with different Le. But in the case of the TD12S, the Zobel "required" is so small it isn't even there. No conjugating, 'cause there's no impedance rise in the passband, through the crossover overlap band.
skywave-rider
Slumming in Akihabara
I have built that and used it on several speakers. It is very flexible because though the x-o point is fixed, it allows a lot of HF manipulation and essentially lets you dial in compensation. One L-Pad sets the very top end attenuation and the other sets the general shelf overall. I have used the Z-19 on BMS drivers and Altec. With the very efficient BMS 4552NDs I had to use more attenuation to match my Altec setup.
I am getting them ready to go back into (on top of) the Altecs.
I think the x-o is about 1.3kHz -- I should know, I measured them a hundred times -- but I forgot.
Anyway, it was fun to build.
Russellc
Addicted Member
Being an Altec man I'm sure you are familiar with their "T-filter compensation"....this is the same thing but with adjustment on the T-filter.
The other is just a L-pad.
Russellc
http://www.audioheritage.org/vbulletin/showthread.php?p=128826&#post128826
I designed it using topology info available on the MarkWart site because people wanted to biamp Model 19s, and I didn't want to mod my vintage pair for that.
Skywave's N-19Z:
Yes, AKers determined that BMS drivers require ~4 - 6 dB more attenuation for the controls to operate in their normal ranges when using them. It's 1.2 kHz, nominal.
Dc270's build using the stock inductors:
I believe I've seen another, but I don't recall where just now.... :yes:
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