Lynn Olson said:
Lynn, do you see any issues with having the tweeter up this high? Sitting on top of 2 - 15s and a 12 puts things at least 45" to the top of the mid/bass module. From my seating position I try not to put my tweeters up past about 30-32" or else funny things happen to the soundstage. That's why I was initally wondering about a solution with an 18 or 21 mated to the 12 mid. 2 -15s and a 12 is one thing if your 12 is a co-ax, but putting a tweeter on top of that seems a bit high.
Please accept this all as a simple question, my expertise is nowhere near yours (or T. Danley, E. Geddes, or John K.'s and probably a few others). I am mearly basing this on some observations of my own system and some others I have listened to.
Hi
Worse! Even from really big and well regarded PRO manufacturers you can get the answer
"CSD? I am afraid I do not know what it is. Sorry."
when asking for a CSD / waterfall plot – as happened to me recently.
-----------------------
Impulse response is a good thing to look at but even more intuitive is CSD IMO. No way to equalise any resonance that shows up. And usually there are several MORE than the prominent one at cone break up – quite often in the most sensitive frequency area.
Some divers that find the way to DIY magazines are measured more extensively. Plots of harmonics at 90dB up to 5-7 order and a plot of harmonics against SPL are very revealing and easy and intuitively to compare.
--------------------
Nice draft on post 1923, Lynn.
I know you love the mirrored bass placed close to the floor and though it is against all physics I would suggest you to lift the OB a rough inch and listen again.
Bass becomes much more " open " and " swingin' " this way.
--------------------------------
BudP, There was a PRO version of that driver with the beautiful name:
" Audax PRD 17 HR 37 TSM KAC "
I happened to find it right at the same time than yours in my loft!
Haven't measured nor listened to it ( sadly don't have a second one.), but telling from ancient plots, FR is even smother throughout and slightly more well behaved at the roll off region.
Surprisingly the flat foam surround is still like new . Compare that to old Dynaudio foam surrounds !
Greetings
Michael
Worse! Even from really big and well regarded PRO manufacturers you can get the answer
"CSD? I am afraid I do not know what it is. Sorry."
when asking for a CSD / waterfall plot – as happened to me recently.
-----------------------
Impulse response is a good thing to look at but even more intuitive is CSD IMO. No way to equalise any resonance that shows up. And usually there are several MORE than the prominent one at cone break up – quite often in the most sensitive frequency area.
Some divers that find the way to DIY magazines are measured more extensively. Plots of harmonics at 90dB up to 5-7 order and a plot of harmonics against SPL are very revealing and easy and intuitively to compare.
--------------------
Nice draft on post 1923, Lynn.
I know you love the mirrored bass placed close to the floor and though it is against all physics I would suggest you to lift the OB a rough inch and listen again.
Bass becomes much more " open " and " swingin' " this way.
--------------------------------
BudP, There was a PRO version of that driver with the beautiful name:
" Audax PRD 17 HR 37 TSM KAC "
An externally hosted image should be here but it was not working when we last tested it.
I happened to find it right at the same time than yours in my loft!
Haven't measured nor listened to it ( sadly don't have a second one.), but telling from ancient plots, FR is even smother throughout and slightly more well behaved at the roll off region.
Surprisingly the flat foam surround is still like new . Compare that to old Dynaudio foam surrounds !
Greetings
Michael
JohnL said:
Well, I like to have the tweeter/midrange crossover region at or above listening level, but never below. In essence, the tweeter/midrange are on or slightly above the horizon line, if there are any windows behind the speakers (the arrangement I had in Portland).
This corresponds to real-life experience in a concert hall or jazz club - we sit down, the musicians stand and do their thing. That to me is a real-life perspective, with the sound coming from close to the floor to a level just above listening height, and bouncing all around a lively-sounding room.
If a genuine real-life perspective sounds "wrong" on a loudspeaker, something is very wrong with the speaker - most probably, vertical polar patterns aimed in the wrong direction. This is actually pretty common with big audiophile speakers. I've heard quite a few expensive speakers that didn't sound coherent unless you laid down on the floor - and sounded utterly unnatural and disjointed when standing. If the "sounds good" zone is 30~32" off the floor, that's a pretty weird listening position - all I can think of is lying down on the couch half-asleep or lying on a bed (and maybe doing other things).
I sit pretty high - the listening height for me is about 40", unless I slouch way down, or sit in a chair that is impossible to get out of since it is so low.
Listening from a height of 40" or more, 30~32" tweeter height sounds squashed and dwarf-sized, and severely compresses the soundstage, giving a bizarre "tabletop" miniaturized sound, like a stereo table radio. Maybe some people like this, to me it sounds extremely unnatural.
Maybe you sit at 30~32" listening height - dunno about your physical size and household furniture - but to me, that tweeter height is very compressed-sounding. I like speakers that sound big and spacious - even the Ariels sound pretty large, far bigger than their physical size would indicate.
Hi Tom,
Wouldn't it be a bit more objective to subject the hifi drivers to similar testing as you do for the pro drivers, than cast judgement leafing through a catalog? I don't totally disagree with you about looks being important for hifi drivers, as they are aimed at audiophiles, who hear with their eyes as much (if not more?) than their ears. But with no data, your statement seems rather subjective. Plus sound quality that is blaring loud enough for public address won't always cut it within the confines of a living room. Different audience requirements.
I, for one, would be interested in what you could come up with. For domestic acoustic spaces, of course. Not open space public address.
What about the low Q resonances within the soft cone drivers passband? What about the flexing and bending of the cone? None pistonic operation? Especially the ultra low mass ones required for HE (pro drivers) attached to powerful motors?
The cone breaking up inside it's passband? A lossy medium is best for signal preservation? Or hiding things?
What if the goal is reproduction of acoustic instruments, not paper cone-compression driver-amplified box speaker-live sound rock concert? Tom, isn't it best to give both sides of the story? Soft, flexy paper cones are without sin?
Is Dr. Toole's research (CMMD) just a marketing gimmick? Thiel?
Last time I checked, there were no paper processed fiber compression drivers. Has that changed?
This is the original NaO correct? As you use to sell it after extensive design, testing and listening? With a clearly audible breakup? Was this audible breakup per customer request? Did they have to pay extra?
An externally hosted image should be here but it was not working when we last tested it.
cheers,
AJ
BTW, Tom, what ever happened to the impulse data for the SH100?
Hi AJ,
No, this is the original NaO:
The original NaO used Scan Speak 8545 mid, as does the current NaO II. Sure the SS have their problem but not like the W18. The picture you are showing is of the NaO AEP (All Excel Panel) which was a short lived (for the reasons I mensioned), one off design variant I made at the time the W18 was very popular. I tried one other variant with the W18 and a sealed box woofer (below) which was enthusiastic received at a DIY event but I quickly grew tired of it too. let me say it again, I don't like metal cones or domes. (Maybe a metal cone woofer? I don't know about that as I haven't looked an any due to my bias.)
We all make mistakes. I certainly not immune.
The original NaO is still supported and has evolved into the current NaO II.
No, this is the original NaO:
The original NaO used Scan Speak 8545 mid, as does the current NaO II. Sure the SS have their problem but not like the W18. The picture you are showing is of the NaO AEP (All Excel Panel) which was a short lived (for the reasons I mensioned), one off design variant I made at the time the W18 was very popular. I tried one other variant with the W18 and a sealed box woofer (below) which was enthusiastic received at a DIY event but I quickly grew tired of it too. let me say it again, I don't like metal cones or domes. (Maybe a metal cone woofer? I don't know about that as I haven't looked an any due to my bias.)
We all make mistakes. I certainly not immune.
The original NaO is still supported and has evolved into the current NaO II.
mige0 said:
I have to disagree with you here. The resonance in most drivers are a linear phenomenon and as such can be equalized. The problem is as Tom said, that while they can be equalized to response correctly to input signals that doesn't solve the problem of them being excited by distortion components generated as harmonis of lower input frequencies. For example, here is a CSD of a naked Seas W18
An externally hosted image should be here but it was not working when we last tested it.
Now, here is a CSD of a 2nd order band pass active filter;
An externally hosted image should be here but it was not working when we last tested it.
Lastly, here is a CSD of the W18 equalized to have the same 2nd order band pass response;
An externally hosted image should be here but it was not working when we last tested it.
It isn't perfect but clearly the resonance at 500, 800, and 5k Hz are not present. The point is that linear systems can always be corrected by response shaping. It is the nonlinearities that cause the problems.
Now, some one asked aboy Floyd Tool. All I can say about that is, for example, a 1st order band pass response has a transfer function given by
TF = (s/Q)/ (1 + S/Q + s^2).
AJinFLA said:
This is the original NaO correct? As you use to sell it after extensive design, testing and listening? With a clearly audible breakup? Was this audible breakup per customer request? Did they have to pay extra?
An externally hosted image should be here but it was not working when we last tested it.
cheers,
AJ
Hi AJ,
I believe that speaker pictured belongs to John Pastuck and was present at the 2004 Iowa DIY Event. It and Salk Sound HT3's were a few tenths apart in the voting for best sound in the unlimited class. I did not hear the ringing John speaks of but I like metal drivers and don't care for the 8545's.
They are very nice speakers.Jim
Hi AInFLA, John K.
“Wouldn't it be a bit more objective to subject the hifi drivers to similar testing as you do for the pro drivers, than cast judgement leafing through a catalog? I don't totally disagree with you about looks being important for hifi drivers, as they are aimed at audiophiles, who hear with their eyes as much (if not more?) than their ears. But with no data, your statement seems rather subjective. Plus sound quality that is blaring loud enough for public address won't always cut it within the confines of a living room. Different audience requirements.”
Several answers;
While at Intersonics my job was to develop new kinds of transducers, “officially” these were for acoustic levitation but I also develop the Servodrive woofer and Phoenix Cyclone rotary woofer and some others while there. I guess from that perspective, I cannot under emphasize that damping is a very important quantity and is not associated with some of the cool looking cone materials.
If looks weren’t apparently more important than sound in some cases, then drivers with nasty behavior wouldn’t be sold based on a “New cone technology”.
It has been a while since I measured any, but I don’t see that they have changed fundamentally since then and if I were building something that used them, I would sample the ones I was interested in.
Your mention of a blaring pa system is spot on in a way.
Most of all the things that are wrong with speakers, get worse as the volume is increased and as the size and complexity of the speaker system increases and also as the room size increases. Often the sale of speakers in this kind of situation is based on hearing side by side demonstrations in the venue. If you can demonstrate better sound, you get the sale most of the time. That kind of puts the focus on better sound and is why I went the way I did.
“What about the low Q resonances within the soft cone drivers passband? What about the flexing and bending of the cone? None pistonic operation? Especially the ultra low mass ones required for HE (pro drivers) attached to powerful motors?
The cone breaking up inside it's passband? A lossy medium is best for signal preservation? Or hiding things?
What if the goal is reproduction of acoustic instruments, not paper cone-compression driver-amplified box speaker-live sound rock concert? Tom, isn't it best to give both sides of the story? Soft, flexy paper cones are without sin?
Is Dr. Toole's research (CMMD) just a marketing gimmick? Thiel?
Last time I checked, there were no paper processed fiber compression drivers. Has that changed?”
Well, all the horn style speakers I build, like the SH-50, only operate the drivers in the piston band. In fact, to reduce distortion, each cone driver feeds into the horn through an acoustic low pass filter comprised of the air volume trapped beneath the cone and a hole which connects to the horn. This low pass filter in front of the driver is above the low pass crossover point and has the effect of attenuating the harmonic distortion the driver produces which comes out above crossover frequency.
With a TEF, one can see a driver which is transitioning to non-piston motion, the old
TEF-10 /12 machines (which were much better in time than the modern ones) one could see the small change in time taking place in a mid range soft dome that had nice smooth response, as the dome de-coupled.
I would think that if you can, you would want to avoid that kind of operation (non-piston) at least where your ears are most sensitive, more or less 300Hz – 3KHz
Bottom line, if you have a mound of acoustic gain between the motor and the net radiation, you magnify the nonlinearity and sub multiples of that F.
On the other hand, if that acoustic gain is in the middle of the band and is broad (low Q) enough, then that can (if eq’d flat) can lower distortion by reducing the drive / excursion of the motor (who’s non-linearity is tied largely to motion).
This is what horns do (one thing), a bass horn that raises the drivers sensitivity by 10dB can reduces its excursion for a given SPL to 1/3 the direct radiator case.
Your comment about compression drivers is related to using metal dome tweeters too.
A dome in a compression driver is one case where strength to weight is a controlling factor as the radiator as mass is more important than in a direct radiator tweeter.
Here, metal or mylar domes are used. A good one inch exit dome type compression driver will have a dome stiff enough (to act like a piston) to reach 17-20KHz before the first resonant mode. Realistically, if you’re an adult, your hearing rolls off before 20KHz and then drops like a rock above 20KHz. I’m not talking about can you detect anything up there under the best case but rather can you hear anything up there under normal conditions, no.
As a result, distortion produced at 5KHz and above has to be at an enormous level to be detectable at all. Similarly peaks and dips associated with breakup, that high, are not generally detectable.
This is not what Earl Geddes is on about, that (HOM’s) are a variable that on one given horn, may make 5 different compression drivers with similar end responses all sound different.
“What if the goal is reproduction of acoustic instruments?”
An ideal reproducer reproduces whatever it is asked to, without alteration in any way.
Like John K. said so well “Door bells and tuning forks should ring, not driver cones.”
No one can convince me that what we have no is so close that we can all give up.
Then there is the recording process and how the speaker interacts with the room, layers which make what the ideal speaker needs to do, less clear.
John K, those are beautiful speakers (all of them).
You obviously have a real knack with math too, very cool.
Again the dogs wish to go, so I must.
Best,
Tom Danley
“Wouldn't it be a bit more objective to subject the hifi drivers to similar testing as you do for the pro drivers, than cast judgement leafing through a catalog? I don't totally disagree with you about looks being important for hifi drivers, as they are aimed at audiophiles, who hear with their eyes as much (if not more?) than their ears. But with no data, your statement seems rather subjective. Plus sound quality that is blaring loud enough for public address won't always cut it within the confines of a living room. Different audience requirements.”
Several answers;
While at Intersonics my job was to develop new kinds of transducers, “officially” these were for acoustic levitation but I also develop the Servodrive woofer and Phoenix Cyclone rotary woofer and some others while there. I guess from that perspective, I cannot under emphasize that damping is a very important quantity and is not associated with some of the cool looking cone materials.
If looks weren’t apparently more important than sound in some cases, then drivers with nasty behavior wouldn’t be sold based on a “New cone technology”.
It has been a while since I measured any, but I don’t see that they have changed fundamentally since then and if I were building something that used them, I would sample the ones I was interested in.
Your mention of a blaring pa system is spot on in a way.
Most of all the things that are wrong with speakers, get worse as the volume is increased and as the size and complexity of the speaker system increases and also as the room size increases. Often the sale of speakers in this kind of situation is based on hearing side by side demonstrations in the venue. If you can demonstrate better sound, you get the sale most of the time. That kind of puts the focus on better sound and is why I went the way I did.
“What about the low Q resonances within the soft cone drivers passband? What about the flexing and bending of the cone? None pistonic operation? Especially the ultra low mass ones required for HE (pro drivers) attached to powerful motors?
The cone breaking up inside it's passband? A lossy medium is best for signal preservation? Or hiding things?
What if the goal is reproduction of acoustic instruments, not paper cone-compression driver-amplified box speaker-live sound rock concert? Tom, isn't it best to give both sides of the story? Soft, flexy paper cones are without sin?
Is Dr. Toole's research (CMMD) just a marketing gimmick? Thiel?
Last time I checked, there were no paper processed fiber compression drivers. Has that changed?”
Well, all the horn style speakers I build, like the SH-50, only operate the drivers in the piston band. In fact, to reduce distortion, each cone driver feeds into the horn through an acoustic low pass filter comprised of the air volume trapped beneath the cone and a hole which connects to the horn. This low pass filter in front of the driver is above the low pass crossover point and has the effect of attenuating the harmonic distortion the driver produces which comes out above crossover frequency.
With a TEF, one can see a driver which is transitioning to non-piston motion, the old
TEF-10 /12 machines (which were much better in time than the modern ones) one could see the small change in time taking place in a mid range soft dome that had nice smooth response, as the dome de-coupled.
I would think that if you can, you would want to avoid that kind of operation (non-piston) at least where your ears are most sensitive, more or less 300Hz – 3KHz
Bottom line, if you have a mound of acoustic gain between the motor and the net radiation, you magnify the nonlinearity and sub multiples of that F.
On the other hand, if that acoustic gain is in the middle of the band and is broad (low Q) enough, then that can (if eq’d flat) can lower distortion by reducing the drive / excursion of the motor (who’s non-linearity is tied largely to motion).
This is what horns do (one thing), a bass horn that raises the drivers sensitivity by 10dB can reduces its excursion for a given SPL to 1/3 the direct radiator case.
Your comment about compression drivers is related to using metal dome tweeters too.
A dome in a compression driver is one case where strength to weight is a controlling factor as the radiator as mass is more important than in a direct radiator tweeter.
Here, metal or mylar domes are used. A good one inch exit dome type compression driver will have a dome stiff enough (to act like a piston) to reach 17-20KHz before the first resonant mode. Realistically, if you’re an adult, your hearing rolls off before 20KHz and then drops like a rock above 20KHz. I’m not talking about can you detect anything up there under the best case but rather can you hear anything up there under normal conditions, no.
As a result, distortion produced at 5KHz and above has to be at an enormous level to be detectable at all. Similarly peaks and dips associated with breakup, that high, are not generally detectable.
This is not what Earl Geddes is on about, that (HOM’s) are a variable that on one given horn, may make 5 different compression drivers with similar end responses all sound different.
“What if the goal is reproduction of acoustic instruments?”
An ideal reproducer reproduces whatever it is asked to, without alteration in any way.
Like John K. said so well “Door bells and tuning forks should ring, not driver cones.”
No one can convince me that what we have no is so close that we can all give up.
Then there is the recording process and how the speaker interacts with the room, layers which make what the ideal speaker needs to do, less clear.
John K, those are beautiful speakers (all of them).
You obviously have a real knack with math too, very cool.
Again the dogs wish to go, so I must.
Best,
Tom Danley
jholtz said:
Hi AJ,
I believe that speaker pictured belongs to John Pastuck and was present at the 2004 Iowa DIY Event. It and Salk Sound HT3's were a few tenths apart in the voting for best sound in the unlimited class. I did not hear the ringing John speaks of but I like metal drivers and don't care for the 8545's.
Jim
Yes, those are John P's speakers. He did a really nice job building them. I think he is in your camp.
The thing about the metal cone mids isn't the ringing per say. As I showed in the CSD plots, with regard to the basic frequency response, it can be shaped given that the breakup is a linear phenomenon. It's the potential for excitation by harmonics of lower frequencies and the resulting "amplification" there of, or excitation from other acoustic sources that is the problem, or so I believe. Response shaping doesn't do anything for these effects since they are introduced independent of the crossover.
I tried to investigate the possibility of acoustic excitation. I set up a second speaker very close to a W18 and played swept sine waves around the resonant frequency to see if the resonance could be excited acoustically while monitoring the W18 voice coil voltage on a scope. The results were inconclusive. I probably should have looked directly at the cone with a laser but I don’t have access to that kind of equipment anymore since I retired.
However, there is something going on with the Seas Excel metal cones (at least the W18 and W22 which I have played with) which catches my ear with long term listening. I find the same problem with other metal cones that I have looked at. Trying to quantify the cause is difficult. It's easy to identify what I hear, much harder to quantify why it is heard. Could be some of: A causes B which (speculatively) results in C, therefore A is the problem. Anyway, the Seas metal cones are very smooth in the pass band but I find that they add a "zip" to the sound that I identify with the resonance (though I could be mistaken), even when carefully addressed in the crossover. And to me this takes something away form what is otherwise excellent. This may be exacerbated by the application since as a dipole mid the W18 is being pushed to the limits, excursion wise. I also think they just sound thin and weak in the lower midrange, but thats a hole other story. Like I said, the 8545 isn’t perfect, but I find the colorations in it more pleasing to my ear than dissonant. There is no question that the W18 and the SS sound different and you’re not the only one who prefers the W18. But I bet you like a Steinway compared to a Baldwin.
Thanks for the kind words about the performance of the system at the Iowa DIY. I think John has done additional tuning of the woofer so it probably sounds better now.
I agree from looking at this data, resonance in most drivers can be equalized; however, due to the fact that resonances occur after the first refleced wave in the cone, an equalized driver will never sound as good as the driver without this resonance. Since we may never be able to do this kind of comparison in reality, knows what we may be missing.
john k... said:
Dr Geddes wrote that non-linear distortions in compression drivers are not the problem. Here my equalised Jordan:
An externally hosted image should be here but it was not working when we last tested it.
I don't hear this pre and post ringing - did the test with minimum and linear phase passband filters.
Can you remember what sample rate these were running at? What driving amplifier did you use? and what kind of speaker cable runs?jzagaja said:
Since these are composed impulses from MLS signals, the pre-ringing is related with the mathematics and is normally not heard. I have discovered though, that when the drivers have good top end frequency extention and can reveal very good detail, the pre-ringing is shown.
I'm not sure whether the equalized performance is better or not, but my guess is there will be some coloration that may or may not be preferable.
Sample rate was 48K (approx. 200 us/div), Pioneer SF-21 amplituner (unknown topology, legato link DAC), Digigram 440VX, cable OFC 2 x 2,5mm2. Cumulative spectral decay of above. I can only say for sure I hear less high frequencies. Which is better - I can't tell. I've never had positive results with DSP. Maybe it's time to visit Dr Brueggmann in Gelsenkirchen HiFi show this November?
I can run direct impulse measurement with 500K sample rate. How short step pulse should be, 50us? Or better calculate impulse response from a step function? Do you know that Shoeps presented on AES conference deconvolving techniques for microphone impulse response estimation? Two microphones and one full range speaker.
I can run direct impulse measurement with 500K sample rate. How short step pulse should be, 50us? Or better calculate impulse response from a step function? Do you know that Shoeps presented on AES conference deconvolving techniques for microphone impulse response estimation? Two microphones and one full range speaker.
This was a long sine sweep de- convolution - Cooledit and Aurora plug-ins.
I don't hear this passband ringing filters on music:
http://audiostereo.lukarnet.com/gfx/800000/808072_1.gif
... except the case when you play the ringing tail alone.
Normally when I try to listen for improvements above 10KHz, cymbals and tambourines are good candidates. More ringing does make the high frequencies seem less, especially if the ringing is 15KHz or above.jzagaja said:
For impulse signals, I would expect the shorter impulse you can output that the amp can handle, the more ideal it would probably be.
I would be interested in reading that Shoeps presentation, is there anyplace it can be found?
I've sent you this paper on email. The author said this approach works best on Manger transducer as an exciter but you can use any wide band driver without crossover and "zeroes in your step response". What he means by that? The disadvantage is you rely on reference microphone.
I apologize for small off-topic.
I apologize for small off-topic.