Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
Well, there certainly seems to be more than I'm used to already, so I'll give them a shot as is, and then give them the brake fluid treatment until the surrounds from Rick arrive..
Russellc
Addicted Member
E'Wavers are certainly a wordy bunch.:
Rollin' over 50,000 views here, momentarily, as well.... :thmbsp:
:beer:
Great thread all around! Of course it has the econowave, but also a great education on its design, especially the compensation part.
We've seen it in about every kind of old speaker system/box, as well as a tutorial on RTA use in conjunction with the build.
We've had tidbits and referals to other threads which can leed to other "not so econowave" versions.
Now, with the help of Jack giff, a tutorial on crossover PC board making, which really excites me.
I fully intend on another "branchout" by trying the charge coupled version of the crossover. i'm kind of waiting for the board instructions first, and that will be 2-3 weeks from what Jack has said.....so maybe wire nuts in the meantime!?
Then I need to get building/finding a box for the 2213H drivers as well, and order another waveguide or two from JBL.
Thanks for the great thread everyone!:thmbsp:
Russellc
Duffinator
Spin The Black Circle
There was a HUGE difference in the bass output when mine were refoamed. The original owner thought they still put out great bass. He was used to the sound deteriorating over the 25+ years he owned them. When I got them home I thought hmmm, there's no bass. Shouldn't a 14" JBL woof have bass? They will have plenty of bass after the refoam. :yes:
skywave-rider
Slumming in Akihabara
Andyman,
Looks like an EconoCornwall.
Where's the port?
Nice boxbuilding!
Looks like an EconoCornwall.
Where's the port?
Nice boxbuilding!
Careful, now, use a brush and don't get any on the cone; just do the "groove" of the inverted roll. :nono:Give um a lube before yu run off to work, let um sit a while.
It may take several thin applications.
And the special lowpass Jack worked out for LE14A.... :yes:
Wayne Parham
Active Member
Vertical nulls
I'm not quite sure how to respond to this except to say that I don't agree, whatsoever. I mean, to minimize this 7.5° null as being "at the ankles" is to pass off marketing rhetoric, in my opinion. It's spin, and it's wrong. Reminds me of some of the political posturing I see these days.
When I see a design that puts nulls at that narrow an angle, I consider it to be a non-viable design. The nulls are damn near straight forward. It's actually hard to position a speaker where that's not audible. So to say it doesn't make a bit of difference in performance when used in the "recommended position" is just dead flat wrong.
Earl repeatedly says his speakers' vertical performance is better than most. That's rubbish. Their verticals are worse than most I've seen. I've solved the problem in my designs, and other conscientious designers have as well. Until Geddes moves to an asymmetrical flare, he will not make a competitive loudspeaker, in my opinion. There are lots of better options, ones that provide smooth amplitude and time response, with uniform horizontal coverage and that don't perform as poorly with respect to the position of the vertical nulls.
It's like Wayne's issue with the lower vertical null occuring at the ankles with the Summas. Could that be improved? Of course. Will it make a bit of difference in performance when used in the recommended position? Uh Uh.
I'm not quite sure how to respond to this except to say that I don't agree, whatsoever. I mean, to minimize this 7.5° null as being "at the ankles" is to pass off marketing rhetoric, in my opinion. It's spin, and it's wrong. Reminds me of some of the political posturing I see these days.
When I see a design that puts nulls at that narrow an angle, I consider it to be a non-viable design. The nulls are damn near straight forward. It's actually hard to position a speaker where that's not audible. So to say it doesn't make a bit of difference in performance when used in the "recommended position" is just dead flat wrong.
Earl repeatedly says his speakers' vertical performance is better than most. That's rubbish. Their verticals are worse than most I've seen. I've solved the problem in my designs, and other conscientious designers have as well. Until Geddes moves to an asymmetrical flare, he will not make a competitive loudspeaker, in my opinion. There are lots of better options, ones that provide smooth amplitude and time response, with uniform horizontal coverage and that don't perform as poorly with respect to the position of the vertical nulls.
It's absurd. You MUST be on-axis vertically, but you CAN'T be on-axis horizontally? It appears to be a tortured rewrite of listening practice to conform with a compromised waveguide design he can build in his garage.
In the waveguide comparo, he didn't post the verticals, saying they were the same as the horizontals. Well, perhaps so, but only so long as the woofer's not running also.
The silence is deafening over there in the Nathan 10 Setup thread since I asked him to post the vertical polars. I hope he's actually measuring to do that; I wouldn't be surprised to learn it's the first time he's done it....
Wayne Parham
Active Member
Well, you're right, Zilch. You're seeing it for what it is, and that's good.
David, I'm sorry if I came across too strongly. No offense intended. But I do think you've bought into Earl's dismissal of the importance of vertical nulls. While I agree with him about many things, on this issue I think he is way off target. He admits that it would be better to have closer-spaced drivers, a limited vertical pattern and wider spacing between vertical nulls. These are all things that an asymmetrical flare can provide. But then when pressed to move in that direction with his designs, he says he is unsure how much benefit it would bring. The proof is in his response charts - The vertical polars look terrible, with nulls very close to the forward axis, and plenty of HF in lobes outside the nulls to bounce off the ceiling and floor.
David, I'm sorry if I came across too strongly. No offense intended. But I do think you've bought into Earl's dismissal of the importance of vertical nulls. While I agree with him about many things, on this issue I think he is way off target. He admits that it would be better to have closer-spaced drivers, a limited vertical pattern and wider spacing between vertical nulls. These are all things that an asymmetrical flare can provide. But then when pressed to move in that direction with his designs, he says he is unsure how much benefit it would bring. The proof is in his response charts - The vertical polars look terrible, with nulls very close to the forward axis, and plenty of HF in lobes outside the nulls to bounce off the ceiling and floor.
When I pressed him on the issue, his response was, basically, "Why should I build something less than perfect?"
Bottom line:
1) It's NOT trivial, and it may very well be he can't do it, or,
2) He's got other priorities.
He was quick to criticize the EconoWave PT for being 6 year old technology, but nobody dares mention that he's been "working" his waveguide theory for 20+ years without commercial success. He's not unsure at all; his initial implementations WERE asymmetric, and they had the same on-axis anomaly. There must be other reasons he abandoned them.... :yes:
Wayne Parham
Active Member
Earl admits that limiting the vertical pattern is desirable, and he also admits that reducing the driver spacing and thereby increasing the null angle is desirable. Then again, I guess it would be hard not to admit that. It's like saying good is good.
Further, Earl has said that an elliptical horn of the same flare shape he uses in his existing designs would accomplish that goal.
The problem is, according to him, they are cost prohibitive to build. Because they are expensive for him to build, he is happy with what he has. He doesn't want to do an "expensive experiment".
Several people have challenged him on this and it seems to have fallen on deaf ears. Most everyone else agrees that a narrow vertical pattern is the way to go. That's why you see so many horns with that basic shape - It works well when combined with other drivers vertically stacked on a baffle.
It's a red herring. The audio loving public is being asked to believe that closely spaced vertical nulls aren't bad, and that the only thing important is the reduction of transverse-mode reflections. The two things aren't mutually exclusive, so there is no good reason to use a round horn except it is what Earl has at the moment.
Further, Earl has said that an elliptical horn of the same flare shape he uses in his existing designs would accomplish that goal.
The problem is, according to him, they are cost prohibitive to build. Because they are expensive for him to build, he is happy with what he has. He doesn't want to do an "expensive experiment".
Several people have challenged him on this and it seems to have fallen on deaf ears. Most everyone else agrees that a narrow vertical pattern is the way to go. That's why you see so many horns with that basic shape - It works well when combined with other drivers vertically stacked on a baffle.
It's a red herring. The audio loving public is being asked to believe that closely spaced vertical nulls aren't bad, and that the only thing important is the reduction of transverse-mode reflections. The two things aren't mutually exclusive, so there is no good reason to use a round horn except it is what Earl has at the moment.
-7.5° doesn't seem too good for a vertical null. is that the result of crossover frequency selection and driver spacing or is it an electrical phenomenon (i.e. retarded phase in the hi frequency driver) which is steering both nulls up?
also, is the ideal placement of nulls always just outside the horn pattern? e.g., placing nulls just outside +/-25° is taken to be ideal for econowave which is a 90°x50° horn; if using a 90°x70° horn, would the ideal placement of nulls be just outside +/-35°?
also, is the ideal placement of nulls always just outside the horn pattern? e.g., placing nulls just outside +/-25° is taken to be ideal for econowave which is a 90°x50° horn; if using a 90°x70° horn, would the ideal placement of nulls be just outside +/-35°?
As side surrounds, yes, absolutely! :thmbsp:
I'm afraid I'm missing your point tho....
Yes, as I understand it.... :yes:
Wayne Parham
Active Member
Excellent question
Excellent question, David, good point.
Would you put together a system with dipoles arranged such that the nulls were 7.5° from the forward axis?
Would you own any sort of loudspeaker with nulls 7.5° from the forward axis?
If you made a DIY speaker and, if after measuring and finding nulls at 7.5° from the forward axis, would you stop there and call it done?
If you wrote a thesis defending your doctorate of a loudspeaker like this, would you expect an "A" grade?
Even a passing grade?
Maybe in high school or at an associates level community college?
Excellent question, David, good point.
Would you put together a system with dipoles arranged such that the nulls were 7.5° from the forward axis?
Would you own any sort of loudspeaker with nulls 7.5° from the forward axis?
If you made a DIY speaker and, if after measuring and finding nulls at 7.5° from the forward axis, would you stop there and call it done?
If you wrote a thesis defending your doctorate of a loudspeaker like this, would you expect an "A" grade?
Even a passing grade?
Maybe in high school or at an associates level community college?
Gedlee said:
http://www.diyaudio.com/forums/showthread.php?postid=1516151#post1516151
I'm looking for the paper showing the earlier elliptical design exhibiting the anomaly; I remember Bauman, I believe....
Wayne Parham
Active Member
Baffle spacing, phase angles and time alignment, revisited
The position of the nulls is determined by driver spacing and crossover phase angle.
I agree with you that having a null 7.5° down from the forward axis isn't very good. It's unacceptable, in my opinion. At 6 feet listening distance, a 7.5° null is less than 10" down from the centerline. That's straight in front of the woofer.
In fact, you have to be 12 feet back before the shallow null angle drops the null to the bottom edge of the speaker, which is where the "ankle" reference comes from. This is a minimizing exaggeration. Any distance less than 12 feet and the null is straight ahead of the speaker. Most people sit less than 12 feet away, so it is probably a good idea that they know a null might be right where they're sitting, producing a 10dB dip at 1.5kHz.
That's what I suggest. It sounds natural because off-axis sound rolls off uniformly rather than having a deep notch midband, and then at higher frequencies having the amplitude rise again. There is no benefit in HF at large vertical angles anyway. It just causes reflections from the ceiling and floor.
The position of the nulls is determined by driver spacing and crossover phase angle.
I agree with you that having a null 7.5° down from the forward axis isn't very good. It's unacceptable, in my opinion. At 6 feet listening distance, a 7.5° null is less than 10" down from the centerline. That's straight in front of the woofer.
In fact, you have to be 12 feet back before the shallow null angle drops the null to the bottom edge of the speaker, which is where the "ankle" reference comes from. This is a minimizing exaggeration. Any distance less than 12 feet and the null is straight ahead of the speaker. Most people sit less than 12 feet away, so it is probably a good idea that they know a null might be right where they're sitting, producing a 10dB dip at 1.5kHz.
That's what I suggest. It sounds natural because off-axis sound rolls off uniformly rather than having a deep notch midband, and then at higher frequencies having the amplitude rise again. There is no benefit in HF at large vertical angles anyway. It just causes reflections from the ceiling and floor.
Wayne Parham
Active Member
I think Earl is hypothesizing here. I don't believe he ever made a PS horn, or elliptical mouth horn of any flare shape. As I recall, in 2005, the only horn he had made was the round OS horns he is currently promoting. Those were reasonably new for him at the time, maybe a year or two, tops.