Re: Re: Accuracy
Yes there is, I do this all the time. Its our standard approach to psychoacoustic testing.
A CD can be turn into a wav file with any number of programs. This is an error free process. Now that wav file can be manipulated in any way that you can think of with either Cool Edit or my favorite MathCad. The original can then be compared to the modified - best done over headphones and here I can only recommend the Etymotic ER4a. This is a very fair comparison with virtually unlimited control over the modifications.
I even have a canned software package that does random presentations of modifications and tracks the users responses. It trains the listener in the begining and then runs the test. If the listener is not doing a satisfactory job of repeatability, it terminates the test and we don't se that listener. This happens about 10-20% of the time.
thomaseliot said:
Yes there is, I do this all the time. Its our standard approach to psychoacoustic testing.
A CD can be turn into a wav file with any number of programs. This is an error free process. Now that wav file can be manipulated in any way that you can think of with either Cool Edit or my favorite MathCad. The original can then be compared to the modified - best done over headphones and here I can only recommend the Etymotic ER4a. This is a very fair comparison with virtually unlimited control over the modifications.
I even have a canned software package that does random presentations of modifications and tracks the users responses. It trains the listener in the begining and then runs the test. If the listener is not doing a satisfactory job of repeatability, it terminates the test and we don't se that listener. This happens about 10-20% of the time.
MBK said:
Yes, I do.
You see the situation with crossover distortion is that the % distortion increases with falling signal level. This is exactly why it is so audible since this is directly opposite to our hearing.
One could therfor ***** crossover distortion by looking at THD as the signal level goes lower, which is a typical measurement. The problem is that virtually all of these THD versus level measurements are THD + noise. When this is the case, the rise in THD at lower signal levels is actually the noise and NOT the distortion. SO this test actually masks the real problem. One would have to track the individual harmonics of the waveform, but then the noise floor is still an issue.
So the measurement problem is one of noise floor and how to measure distortion products down below this floor.
This is done by averaging. But normal averaging can only lower the noise floor so much - down to the noise power. But if I have a signal and I average this signal sychronously then I can raise the net signal to noise level. This too is common. But if the signal does not exactly fit the time base then I need to window it and the resultant spectral leakage makes this sychronous averaging less effective.
I use a signal that exactly fits into the time base of the A/D taking the data. This means that I don't have to use a window and I can sychronously average a signal to noise ratio that is about 20 dB better than a simpler test could achieve. This means for example that the input signal needs to be something like 976 Hz not 1000 Hz, which doesn't exactly fit the window.
I actually had to generate the input wav file in FORTRAN using quad precision, special random number generators and rounding techniques, because the test signals needed to have a 120 dB dynamic range - very difficult with 16 bits.
I use a signal that starts out low and goes up in level. I plot out the results as the signal drops into the noise floor. This test shows vast differences in amps that measure identical with standard tests.
It also shows that my Pioneer amp - you know the "really crappy" one that I get crticized for using at RMAF - is an extremely good amplifier. As good as the best that I have tested with this technique.
MBK said:
Sure you could, its trivial to setup. ALL you need is the calculation software. I can probably supply that to you. I would just want to make sure that the technique and my software are not used without due acknowledgement of the author. I'm not just going to post it. I've done that before and no one ever credits the original source.
You need to be able to output a wave file to the amp and then sample the amps output across a load resistor. Its best if you go fairly high in power down, so that requires a high power load resistor. Everything else is a sound card and software.
At any rate, if we are to continue this discussion lets get off of Lynns post to a new one.
Brett said:
Well, I usually balance my systems to sound like a stacked Quad 57 - in fact, there are several Quad 57 owners who now have Ariels, and find the two very close in character and transparency. Since it's difficult to describe the sound of a loudspeaker without lapsing into reviewer-speak, I tell people if they like Quad ESL57's and BBC monitors, they'll probably like what I do, but if they're Altec and JBL fans, they almost certainly won't.
SunRa said:Hello Mr. Olson,
are you still considering the tonetubby alnico for the low section? I'm asking because I've seen some 15' alnico guitar drivers made by Weber here. Unfourtunately no specs, he makes them by ear, however they are quite aclaimed in some comparisons I've read against celestion and others. So I asume the region up to 1Khz it's nice and clean, while the break-up point is controled by various design aspects. He even makes them custom, to the tone you want of course.
And what are the crossover points for the woofer(s)? As I understand there will be a low pass at the point the midbass rolls-off because of the OB and then another low pass at around 1Khz for the midbass and the woofers?
edit: a friend of mine, a member on this forum auditioned some 15' webers and he could make a comparison to his own eminences 15' in open baffle. He was quite impressed. In fact very impressed. I know he prefers warm bass though, so I have a slighty reticence because I didn't listened to a guitar driver (rich armonics and so on) with usual music content.
Boy, that's a hard one to answer. Most guitar speakers have really wacko response curves and Xmax so small that it's not even quoted - some of them don't have any linear region at all. But they're not meant to - they're part of a musical instrument, and are intended to have a tonal character that changes dynamically with the playing style of the guitarist.
I think it's just a happy accident the 12" Alnico Tone Tubby sounds surprisingly good - a bit like a Lowther, which sounds much better than the measurements would indicate. But whenever this happens, I admit I remain suspicious - keep trying different program material, and the coloration usually comes out of hiding - although I've heard a lot of Lowthers, and I keep being surprised. Maybe it's a certain type of "vintage" coloration I like without being aware of it.
The Eminences just don't do anything for me - the few I've heard sound flat and undynamic, but Eminence makes a zillion loudspeaker drivers, and surely they must sound different from each other.
I think some of the enthusiasm for guitar speakers is the choice of Alnico magnets, paper VC formers, and traditional cone materials and glues. All of those together will have a fairly authentic "vintage" sound, which has a set of hard-to-define virtues not present in modern drivers. The Bastanis Apollo, for example, used what was obviously an Alnico-magnet guitar speaker - maybe a Celestion Blue, but I don't remember the details that clearly. Rob Bastanis said it was of "Eastern European" origin, which could mean anything.
My reservations about using the Tone Tubby, or the Celestion Blue, is the awkwardness of equalizing the 1~5 kHz region. I've heard rumors that A Broun Soun makes OEM hempcone drivers for hifi manufacturers, but there is no info on this - OEM specs are usually behind a veil of non-disclosure agreements.
The thing that is so memorable about the combination of paper VC formers and Alnico magnets are the vivid, shimmering tone colors, quite unlike modern audiophile drivers. I don't think is all due to mid/hi colorations - there are plenty of modern drivers with really terrible mid/hi response, and they don't sound a bit like the vintage-school drivers, they just sound harsh, as the measurements would lead you to expect. So I think there is something really there with the Tone Tubby, Webers, the mystery driver in the Apollo, and the Alnico Lowthers. I just don't know what it is.
So - if you're adventurous, and have the courage to do your own crossover design - my instinct is that this family of drivers could prove quite rewarding. Unlike many others, they tend to be quite musical without any EQ at all, despite frightening-looking curves.
If you wanted an OB with an "attitude", the version posted previously with 3 x 12 drivers could be built with a single Alnico 12" Tone Tubby and two of the 12" ceramics, two Alnicos and one ceramic, or three Alnicos (reserving Alnico for the midbass in all versions). You trade Xmax for more vivid tone colors, and the rise in the 1~5 kHz region doesn't matter as much for the midbass and bass drivers, which are rolled off anyway.
For the widerange driver, you can then use the 18Sound 8NMB420 mentioned earlier (easy to equalize), or go out an a limb and choose Lowther, AER, or Fertin 8" widerange drivers. Now that would be an adventurous loudpeaker.
Hello Mr. Olson,
thanks for the reply. It was essentialy what I had in mind. You have the high efficiency, alnico and paper camp on one side and the rest of PA on the other. However there is something that feels right with drivers like supravox, fertin, lowther and so on... but not the price.
Today I'm feeling a little to adventurous I guess. Feastrex anounced their presents at RMAF here , room 9003. The little midrange they had was of no relevance for this project but they have a new one, the 9x . This comes with all the whissles, from the naturflex circuit to alnico/permadur and field-coil. I'd love to have the chance to listen them but a trip around the worl for this isn't what I have in my plans this autumn.
thanks for the reply. It was essentialy what I had in mind. You have the high efficiency, alnico and paper camp on one side and the rest of PA on the other. However there is something that feels right with drivers like supravox, fertin, lowther and so on... but not the price
.Today I'm feeling a little to adventurous I guess. Feastrex anounced their presents at RMAF here , room 9003. The little midrange they had was of no relevance for this project but they have a new one, the 9x . This comes with all the whissles, from the naturflex circuit to alnico/permadur and field-coil. I'd love to have the chance to listen them but a trip around the worl for this isn't what I have in my plans this autumn
.
This thread is so long it is hard to get a handle on who has actually built what so far. Given that I started building something along this line around a year ago, and that I have had the chance to see the 18sound drivers first hand, I'll add what I can. Do keep in mind that I admit to not knowing a dang thing about how to build a speaker
The 18" 18sound driver has a very thick and heavy cone. I doubt you guys would be happy unless it was horn loaded. They have some 15" drivers that look very nice but are fairly low Qts and would need some EQ'ing. Fs averages upper 30's. Usher makes a 15" worth a look with a Fs of 25 and reasonable power handling. Eminence is okay to my ears if I cross low enough. 100 hertz is cool but by 200 hertz you notice them.
Regarding the mid range....if you are willing to cross around 200 hertz there are a lot of drvers out there to consider. I can see anything from a newish 6" to an older stlye 12" (alnico) working depending upon desired crossover points. From what I hear, if you can manage close to a 100 hertz on the bottom and near 2khz on the top the other driver choices become easier. The lower you want to cross the more the older/larger drivers appeal. I have not formally mounted the 12" alnicos yet but have used a 6.5" (audax) for several months with good results. I wouldn't want to run a 12" up around 3khz+. I cross my 6.5" at 1k8 (near its first breakup mode) but many run it much higher. I gained a little extra warmth doing so but the compression driver was so much cleaner/dynamic I can't see the wisdom of not using it.
I guess where I really depart from the this thread is my treble solution. I was influenced by Dr. Earl and the summas. I went the CD waveguide route. I use the 18sound xt1086 with nd1090. Given its price I am impressed with this horn. I played a bit with adding a rear firing tweeter, and with dipole treble (heil amt) and didn't care for either. To my ears treble isn't the place to add extra reverberant info. I understand this is counter to what others are preaching but I can only report my findings. Excellent chance this is due to my very live room (all concrete/plaster, no rugs, little furniture).
To date there is only one ribbon tweeter I heard that I felt the equal of the xt1086 solution and that was a stage accompany. That said I haven't heard many, but to me they lack that extra bite that is called for with certain types of music.
On the crossover/amp end....I'd say go active between woofer and mid and passive between mid and high. With the right driver choices I can see a few class A tube watts (set 300b/pp 2a3) doing 120db with occasional 130db peaks. For the bass you are kidding if you don't have at least a 100 watts and a good bit more wouldn't be absurd. For bass freaks consider the need for adding a monopole sub to pressurerize the room.
I have heard the lowther and the basszilla speaker is quite nice. I didn't care for the medallions.
Russ
The 18" 18sound driver has a very thick and heavy cone. I doubt you guys would be happy unless it was horn loaded. They have some 15" drivers that look very nice but are fairly low Qts and would need some EQ'ing. Fs averages upper 30's. Usher makes a 15" worth a look with a Fs of 25 and reasonable power handling. Eminence is okay to my ears if I cross low enough. 100 hertz is cool but by 200 hertz you notice them.
Regarding the mid range....if you are willing to cross around 200 hertz there are a lot of drvers out there to consider. I can see anything from a newish 6" to an older stlye 12" (alnico) working depending upon desired crossover points. From what I hear, if you can manage close to a 100 hertz on the bottom and near 2khz on the top the other driver choices become easier. The lower you want to cross the more the older/larger drivers appeal. I have not formally mounted the 12" alnicos yet but have used a 6.5" (audax) for several months with good results. I wouldn't want to run a 12" up around 3khz+. I cross my 6.5" at 1k8 (near its first breakup mode) but many run it much higher. I gained a little extra warmth doing so but the compression driver was so much cleaner/dynamic I can't see the wisdom of not using it.
I guess where I really depart from the this thread is my treble solution. I was influenced by Dr. Earl and the summas. I went the CD waveguide route. I use the 18sound xt1086 with nd1090. Given its price I am impressed with this horn. I played a bit with adding a rear firing tweeter, and with dipole treble (heil amt) and didn't care for either. To my ears treble isn't the place to add extra reverberant info. I understand this is counter to what others are preaching but I can only report my findings. Excellent chance this is due to my very live room (all concrete/plaster, no rugs, little furniture).
To date there is only one ribbon tweeter I heard that I felt the equal of the xt1086 solution and that was a stage accompany. That said I haven't heard many, but to me they lack that extra bite that is called for with certain types of music.
On the crossover/amp end....I'd say go active between woofer and mid and passive between mid and high. With the right driver choices I can see a few class A tube watts (set 300b/pp 2a3) doing 120db with occasional 130db peaks. For the bass you are kidding if you don't have at least a 100 watts and a good bit more wouldn't be absurd. For bass freaks consider the need for adding a monopole sub to pressurerize the room.
I have heard the lowther and the basszilla speaker is quite nice. I didn't care for the medallions.
Russ
HI
Wow, 91 pages...
I'm happy to finally contribute.
The subbass section is still an unsolved problem.
At the very first, Lynn seem tempted by the rythmik sub.
As an owner of a pair of servo12, i'm happy but Lynn also mentionned that he want headroom and solid SPL capability.
Beside a quad of servo12 or a pair of servo15, this might be hard to realize.
Here a link of various sub measurement (include the rythmik servo12)
http://www.hometheatershack.com/for...index-subwoofer-tests-manufacturer-model.html
The guy seem serious, as his measurement's method.
http://www.hometheatershack.com/forums/subwoofer-tests/971-subwoofer-tests-explained.html
As a personal comment, I like my rytmik but I now living in a small appartement and can't consider a fridge sized sub.
I can't detail further because they are my first "mini sized subs" and I didn't hear other for comparaison.
If space wouldn't be an issue, the seismic from Edgarhorn are by far the best bass I ever hear
I just imagine them mated with a decent pair of electrostat (use to own acoustat 2+2 fullrange direct driven by an massive tube amp with passive EQ)
Wow, 91 pages...
I'm happy to finally contribute.
The subbass section is still an unsolved problem.
At the very first, Lynn seem tempted by the rythmik sub.
As an owner of a pair of servo12, i'm happy but Lynn also mentionned that he want headroom and solid SPL capability.
Beside a quad of servo12 or a pair of servo15, this might be hard to realize.
Here a link of various sub measurement (include the rythmik servo12)
http://www.hometheatershack.com/for...index-subwoofer-tests-manufacturer-model.html
The guy seem serious, as his measurement's method.
http://www.hometheatershack.com/forums/subwoofer-tests/971-subwoofer-tests-explained.html
As a personal comment, I like my rytmik but I now living in a small appartement and can't consider a fridge sized sub.
I can't detail further because they are my first "mini sized subs" and I didn't hear other for comparaison.
If space wouldn't be an issue, the seismic from Edgarhorn are by far the best bass I ever hear
I just imagine them mated with a decent pair of electrostat (use to own acoustat 2+2 fullrange direct driven by an massive tube amp with passive EQ)
Russ57,
Don't worry. It is at times difficult for all of us to follow along in this thread. Sometimes it is over my head and I just wait for design decisions to be made and prototypes to follow. At this point Lynn needs to get better (physically) and start acquiring drivers to listen to to start making these decisions.
My 2 cents,
C
Don't worry. It is at times difficult for all of us to follow along in this thread. Sometimes it is over my head and I just wait for design decisions to be made and prototypes to follow. At this point Lynn needs to get better (physically) and start acquiring drivers to listen to to start making these decisions.
My 2 cents,
C
Better than nothing.
Getting close to something showable, but keep changing my mind as to baffle. Speakers and electronics are all waiting. This time a baffle change was because of a 2hr+ phone conservarsation with Bill Allen from Bauls Audio (Bastanis rep).
He was very enlightening and shared some thoughts on doing a Bastanis wannabe on the cheap as well as getting bass from a smaller than computer designed sealed woofer. I'm a little fuzzy there, but I think I got enough info to try one someday.
This doesn't help in show and tell but at least I did show up with something pseudo-positive on the construction end.
I sure hope most of you aren't just waiting for Lynn. Guessing that's the last thing he wants. Build it and show, it might be great or laughable (mine). Only good will come from any design. If no pictures and attached words, we cannot comment, pick apart (that is not bad), praise or what-ever. Where did this nicety nice crap (word is cr*p, see what I mean) come from? If mine is stupid, it's just stupid and I don't find any offense in hearing such comments. What, the cavemen just got up one day and walked? There were giggles galore as he first tried.
So if it's not approved by the elite builders, then it's no good? Give me a break.
If that sounds like my old speech of "lets get it on" and less babble, you are dead right.
Zene
Getting close to something showable, but keep changing my mind as to baffle. Speakers and electronics are all waiting. This time a baffle change was because of a 2hr+ phone conservarsation with Bill Allen from Bauls Audio (Bastanis rep).
He was very enlightening and shared some thoughts on doing a Bastanis wannabe on the cheap as well as getting bass from a smaller than computer designed sealed woofer. I'm a little fuzzy there, but I think I got enough info to try one someday.
This doesn't help in show and tell but at least I did show up with something pseudo-positive on the construction end.
I sure hope most of you aren't just waiting for Lynn. Guessing that's the last thing he wants. Build it and show, it might be great or laughable (mine). Only good will come from any design. If no pictures and attached words, we cannot comment, pick apart (that is not bad), praise or what-ever. Where did this nicety nice crap (word is cr*p, see what I mean) come from? If mine is stupid, it's just stupid and I don't find any offense in hearing such comments. What, the cavemen just got up one day and walked? There were giggles galore as he first tried.
So if it's not approved by the elite builders, then it's no good? Give me a break.
If that sounds like my old speech of "lets get it on" and less babble, you are dead right.
Zene
Hi
Sure !
But mine still is in test / BETA stage.
Currently I am checking out the multi baffle approach not really following the suggestions of this thread ( whatever you take ) in any way.
Its 2.5 right now ( the way I suggested to split the power rather than just adding the lowest speaker by an unsymmetrical 6 dB XO ) and not appealing enough to show pics.
The front tweeter still is the Seas Excel Millennium shown in early pics and the mid-high baffle also still is of same size. Have experimented with a rear tweeter ( ScanSpeak D2010 the one with the foam face plate ) I had at hand and found it an considerable improvement even in my low dampened small room ( made me grin when I read Lynns posting 2240 ).
From that experience a rear tweeter is a must IMO, no matter how bright your room is.
Mid is the ancient paper dome I mentioned earlier – measuring catastrophic bud I like a certain something it has (nothing to recommend though).
Still awaiting some further details of an interresting 8" under development from Perry Pecker at HEMP Acoustics. Preliminary FR looks breathtaking flat up to 5k with 90 dB efficiency and having a beautifull phase plug
Also bass isn't ready yet. Further iterations convinced me to keep it off the floor wasting efficiency and lower distortion. Had a second couple of the paper cones there and replaced it recently with the Peerless SLS 12 ( 830669 ) .
Having only few hours listened after break in I can recommend that driver to consider seriously having quite some of the paper cone appeal and having around 16 mm X lin p-p (efficiency is around 90 dB ).
For now bass is on a separate folded baffle and next will be to check out the cardioid types.
Sadly time is limited and in parallel I am evaluating PC XO possibilities.
Greetings
Michael
john k... said:
AFAIK nothing has been build. This thread seems to have turned more into a discussion group of its own than a progress reprot.
Sure !
But mine still is in test / BETA stage.
Currently I am checking out the multi baffle approach not really following the suggestions of this thread ( whatever you take ) in any way.
Its 2.5 right now ( the way I suggested to split the power rather than just adding the lowest speaker by an unsymmetrical 6 dB XO ) and not appealing enough to show pics.
The front tweeter still is the Seas Excel Millennium shown in early pics and the mid-high baffle also still is of same size. Have experimented with a rear tweeter ( ScanSpeak D2010 the one with the foam face plate ) I had at hand and found it an considerable improvement even in my low dampened small room ( made me grin when I read Lynns posting 2240 ).
From that experience a rear tweeter is a must IMO, no matter how bright your room is.
Mid is the ancient paper dome I mentioned earlier – measuring catastrophic bud I like a certain something it has (nothing to recommend though).
Still awaiting some further details of an interresting 8" under development from Perry Pecker at HEMP Acoustics. Preliminary FR looks breathtaking flat up to 5k with 90 dB efficiency and having a beautifull phase plug
Also bass isn't ready yet. Further iterations convinced me to keep it off the floor wasting efficiency and lower distortion. Had a second couple of the paper cones there and replaced it recently with the Peerless SLS 12 ( 830669 ) .
Having only few hours listened after break in I can recommend that driver to consider seriously having quite some of the paper cone appeal and having around 16 mm X lin p-p (efficiency is around 90 dB ).
For now bass is on a separate folded baffle and next will be to check out the cardioid types.
Sadly time is limited and in parallel I am evaluating PC XO possibilities.
Greetings
Michael
Thanks Earl.
I am assuming that I will take some damage, or a lot of damage, from trying to get folks to untie their brains from piston theory, in analysis programs. Certainly my lonely efforts have born zero fruit in ten years and, as it is, if Dan Wiggins had not done the research he has and decided he needed to solve the final problem with drivers, I would still be without traction of any sort. Certainly does not look as if that relationship will bear any fruit and my dealings with Perry may not work out either, but he has gotten the attention of a major cone maker and they are interested enough to spend some money to attempt to make the process transparent in cost.
When you have a process that forces a driver to act like a properly terminated transmission line, and are faced with a world of piston theory, any interest and movement is welcome. So, frankly, whatever Perry does suits me just fine, so long as he makes enough noise in the professional circles that some folks get interested enough to dig into something uncomfortable and new.
Earl, are you back in the states now? If so, are you going to the RMAF? I ask because Lowther America will have a Friday evening demo of EnABL treated and untreated PM6A drivers.
My reason for asking is because you have skills on both sides of the fence and my hope is that upon hearing what is different, not better, just different, you might have some suggestions for test methods that could uncover the changes. Soongsc has shown some startling test results, but I will have to convince some pretty hard headed money guys, in places like Hammond and Bose, that I didn't just finish smoking my favorite mind altering drug. So, I though I would ask for an opinion, if you do attend and have some time to spend.
Plus, I wanted to invite anyone else who is attending RMAF, and I am not, to stop by at the Lowther America room on Friday evening, for a demo, so you will know why I keep popping up here with the same old song.
Bud
I am assuming that I will take some damage, or a lot of damage, from trying to get folks to untie their brains from piston theory, in analysis programs. Certainly my lonely efforts have born zero fruit in ten years and, as it is, if Dan Wiggins had not done the research he has and decided he needed to solve the final problem with drivers, I would still be without traction of any sort. Certainly does not look as if that relationship will bear any fruit and my dealings with Perry may not work out either, but he has gotten the attention of a major cone maker and they are interested enough to spend some money to attempt to make the process transparent in cost.
When you have a process that forces a driver to act like a properly terminated transmission line, and are faced with a world of piston theory, any interest and movement is welcome. So, frankly, whatever Perry does suits me just fine, so long as he makes enough noise in the professional circles that some folks get interested enough to dig into something uncomfortable and new.
Earl, are you back in the states now? If so, are you going to the RMAF? I ask because Lowther America will have a Friday evening demo of EnABL treated and untreated PM6A drivers.
My reason for asking is because you have skills on both sides of the fence and my hope is that upon hearing what is different, not better, just different, you might have some suggestions for test methods that could uncover the changes. Soongsc has shown some startling test results, but I will have to convince some pretty hard headed money guys, in places like Hammond and Bose, that I didn't just finish smoking my favorite mind altering drug. So, I though I would ask for an opinion, if you do attend and have some time to spend.
Plus, I wanted to invite anyone else who is attending RMAF, and I am not, to stop by at the Lowther America room on Friday evening, for a demo, so you will know why I keep popping up here with the same old song.
Bud