The definitions of DR are right, but not what I think the OP is alluding to.
When people speak of a dynamic speaker, I think they are referring to a sense of subjective impact, which is very different.
To me a speaker lacking dynamic impact is one which behaves like a limiter, chopping off peaks because of the drivers' limitations. In this case, looking at the Xmax on a woofer, it might only be responding by travelling say 90% of what the I/P signal is feeding it, so a reduced actual X travel.
Much of the sense of both transients, and this dynamic feel are conveyed IMO by frequencies towards the middle, these providing the 'sharpness' of a fast peak, as in a step edge.
When people speak of a dynamic speaker, I think they are referring to a sense of subjective impact, which is very different.
To me a speaker lacking dynamic impact is one which behaves like a limiter, chopping off peaks because of the drivers' limitations. In this case, looking at the Xmax on a woofer, it might only be responding by travelling say 90% of what the I/P signal is feeding it, so a reduced actual X travel.
Much of the sense of both transients, and this dynamic feel are conveyed IMO by frequencies towards the middle, these providing the 'sharpness' of a fast peak, as in a step edge.
It's called harmonics, and it's a fact than ringing in the waterfall of the tweeter miniminize the snap/impacts... if snaps are weak, work on your tweeter as well.
The subject is complex and goes upon than ESL or no ESL...that's why we are sometimes OT....
Cool thread btw Discopete...thanks.
Has anyone tried a first order super tweeter on their esl...13 Khz or more for a long overlaping ? Some ESL are not to weak in the highs treble because the behavior of the full range diagphragm ? Or is it because of the dipole behavior and a too much damped or not listening room as well ?
The subject is complex and goes upon than ESL or no ESL...that's why we are sometimes OT....
Cool thread btw Discopete...thanks.
Has anyone tried a first order super tweeter on their esl...13 Khz or more for a long overlaping ? Some ESL are not to weak in the highs treble because the behavior of the full range diagphragm ? Or is it because of the dipole behavior and a too much damped or not listening room as well ?
For a few decades, I used little round tweeters from Denesen (who was the mentor or partner or not clear the relationship) to Jantzen. I made a curved panel with four unit each side.
Yes, did brighten up my Dayton-Wrights. But the DW were playing inside the gas bag and the stock units had ceramic tweeters inside the box to enhance the treble (OK, don't make jokes about ceramic tweeters... I am sure they tested very well).
However, when I returned to my DIY 1978 ESLs, made from DW panels, they were as bright and fine as could be. And need no enhancement in the tweeter band. And played pretty strongly down to 100 Hz.
Frankly, a lot of the dipole versus less pole discussion here seems speculative to me (a polite way of saying something harsh). I suspect the generally omni performance of dipoles is the natural way to introduce reproduced music to a room and the point-source isn't, even if a point source with pure phase truth appeals to those who like geometric simplicity.
Less pole should not go to less polite for us to understand your claims, sure 
...
Anyway dipole things most advantages is too make the room defaults more forgiving. That's why you, we, like it... often the Lxlxh ratio of the room is simply not good and waste many efforts in the wide frequency range and in bass area especially below Helmothz frequency which is real and not too much about bulls atributes imho.
I do agree mid bass slam should be light and informative like some figured it out here.
Cost no object, myself I would go for the Quad ESL 63 stacked... Quad was for quattro imho... and it's a little more than dipole, with its circular delay thingy, Peter Walker was a genius imho.
Add indeed a dipole low bass device a la Linkwitz, CharlieM, N Pass way...or servo bass distributed sub a la Geedle (to minimize room signature and putt the sweet spot in a high pressure zone for the low register to avoid pump up the bass volume) and you should have it. Peole think it's about moving air in the bass, but air moleculs don't move...they mainly transmit a vibration from air moleculs to others air molecules...pression involved on the thympanic membrane is very low, yet it seems needed prezurisation of the room in the bass area seems to think some guys as Toole ?
I also think there is psychoacoustical habit behavior plus bias...many audiophile like their own bad sounds... At home I check my diy by non hifi buddy who are musicians
... Anyway dipole things most advantages is too make the room defaults more forgiving. That's why you, we, like it... often the Lxlxh ratio of the room is simply not good and waste many efforts in the wide frequency range and in bass area especially below Helmothz frequency which is real and not too much about bulls atributes imho.
I do agree mid bass slam should be light and informative like some figured it out here.
Cost no object, myself I would go for the Quad ESL 63 stacked... Quad was for quattro imho... and it's a little more than dipole, with its circular delay thingy, Peter Walker was a genius imho.
Add indeed a dipole low bass device a la Linkwitz, CharlieM, N Pass way...or servo bass distributed sub a la Geedle (to minimize room signature and putt the sweet spot in a high pressure zone for the low register to avoid pump up the bass volume) and you should have it. Peole think it's about moving air in the bass, but air moleculs don't move...they mainly transmit a vibration from air moleculs to others air molecules...pression involved on the thympanic membrane is very low, yet it seems needed prezurisation of the room in the bass area seems to think some guys as Toole ?
I also think there is psychoacoustical habit behavior plus bias...many audiophile like their own bad sounds... At home I check my diy by non hifi buddy who are musicians
DrJJ,
Thanks for the input on crossover frequency. I do not disagree with you. The Sound Lab interface has two transformers for hi and low frequencies. I believe Dr. West chose 500hz because that was where the crossover between the two transformers/circuitry occurs (on the original interface that I had). Operating at 500hz limits operation to toroidal hi frequency transformer. Needless to say, I upgraded the transformer that allowed me to lower the crossover point such that I am using only the toroidal at 100-200hz and above.
I would point out that off loading the bass to a separate panel does provide noticeable sonic benefits versus running them full range.
Thanks for the input on crossover frequency. I do not disagree with you. The Sound Lab interface has two transformers for hi and low frequencies. I believe Dr. West chose 500hz because that was where the crossover between the two transformers/circuitry occurs (on the original interface that I had). Operating at 500hz limits operation to toroidal hi frequency transformer. Needless to say, I upgraded the transformer that allowed me to lower the crossover point such that I am using only the toroidal at 100-200hz and above.
I would point out that off loading the bass to a separate panel does provide noticeable sonic benefits versus running them full range.
Harmonics will affect the decay because of stored energy, but how can that affect the rise time?
If I'm correct, it's more the harmonics that can be affected by a too long decay of the drivers (resonances, peaks you see on the waterfall) , when you listen to a slam, impact, you don't hear only the fundamental. It seems all the harmonics are involved to make it tight and dry; so till tweeter spectrum, all of this being extremely breif as we are talking of short time windows between the lowest and the higest spl - drums attack for illustration- till hearable for the ears/brain. I read somewhere the limit of brain is 2 ms, below the brain can not see timing difference. the challenge is also the amp and source to be accurate amp being able to control the "driver"...also stop it without ringing when it needs. It also seems the wider the band of the driver, the more complex the behavior of the driver and its controll... low excursion techs winn here... ESL, compression drivers... So several roads for the same destination, different trade offs though as figured out (max spl, room, ...)
Darn it! I was just completing a thoughtful reply to this message, and simply it disappeared. Has that ever happened to anyone else?
Ah! That explains what I thought was an odd crossover frequency choice.
I'll offer the caveat that I don't know the speakers that you using at all. Simplifying somewhat, I'd think that the SPL falloff with distance and the vertical frequency response should not change with crossover frequency.
Where it matters is is in the lateral direction. The higher the crossover frequency, the greater the lateral variation of frequency response. The lower you go, the smaller the variation, within limits. But the limitation is that the lower you go, the more SPL you lose on your main speakers.
It sounds like you have the ability to change crossover frequency. If you do, I'd start at 100 Hz and measure the lateral frequency response if you have the tools. Measure distortion with SPL too. If distortion gets too high at the SPLs where you wish to listen, raise the frequency until you get to a compromise you can live with.
For reference, A440 is the A above middle C on the piano. 200 Hz is about an octave below that, which I'd still count as lower midrange. 100 Hz is an octave below that, and I'd call that upper bass. The wavelength there is about 10 feet, and that probably exceeds the distance from the outside of your main panels to the far side of your woofers. The piano has another two octaves of range below that, so that still will be a massive reduction in the excursion of your main panels.
In all, though, I think these are good problems to have!
to this message, and simply it disappeared. Has that ever happened to anyone else?Ah! That explains what I thought was an odd crossover frequency choice.
I'll offer the caveat that I don't know the speakers that you using at all. Simplifying somewhat, I'd think that the SPL falloff with distance and the vertical frequency response should not change with crossover frequency.
Where it matters is is in the lateral direction. The higher the crossover frequency, the greater the lateral variation of frequency response. The lower you go, the smaller the variation, within limits. But the limitation is that the lower you go, the more SPL you lose on your main speakers.
It sounds like you have the ability to change crossover frequency. If you do, I'd start at 100 Hz and measure the lateral frequency response if you have the tools. Measure distortion with SPL too. If distortion gets too high at the SPLs where you wish to listen, raise the frequency until you get to a compromise you can live with.
For reference, A440 is the A above middle C on the piano. 200 Hz is about an octave below that, which I'd still count as lower midrange. 100 Hz is an octave below that, and I'd call that upper bass. The wavelength there is about 10 feet, and that probably exceeds the distance from the outside of your main panels to the far side of your woofers. The piano has another two octaves of range below that, so that still will be a massive reduction in the excursion of your main panels.
In all, though, I think these are good problems to have!
Yes the speed of a transient sound will be greatly contributed to by the harmonics, probably from other drivers than a woofer.
You may be referring to the Haas effect, or 'fusion', describing the inability to separate two sounds closely produced in time; the brain combines them.
The failures of drivers can only be limited to an extent by an amplifier, that of the amplifier having a very low O/P impedance to ensure the drivers back emf is presented maximally back to the driver. But drivers all behave in a rather 'out of hand' and uncontrolled way even with good amplifier damping.
Low diaphragm or cone mass, is what really helps to preserve the following of a waveform, and the ESL diaphragm is light, but large.
Stacked 63s
Thanks for this thread - it's reminding me to get my **** in gear. Just recovering from a torn tendon in my foot, then I'll enlist the help of friends to carry them into the lounge once fixed.
The sound was phenomenally good.
Hmm, I'm lucky enough to have a stacked pair just need to replace a broken fuse holder on one unit, then they can be powered and tested. They have been off for at least twelve years in total now. Bought them from a very good friend's daughter 2 years ago. Been a while since he passed away. George was my senior by 35 years but we had the same taste in music - jazz, blues, classical. I was lucky to get all of his kit - Quad Pre, DIY mosfet amp, Thorens 124 and early Phillips 16-bit CDP.
Thanks for this thread - it's reminding me to get my **** in gear. Just recovering from a torn tendon in my foot, then I'll enlist the help of friends to carry them into the lounge once fixed.
The sound was phenomenally good.
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I'm curious about how stacked ESL-63s work for you.
Conceptually the 63 is a point source. So you would have two point sources separated by some distance. Below the half the frequency of that distance you should be fine. Above that I'd think you'd get all sorts of comb filter effects that depend strongly on location. But real life, and in real rooms, it may turn out differently.
Please let us know how it works out for you.
Conceptually the 63 is a point source. So you would have two point sources separated by some distance. Below the half the frequency of that distance you should be fine. Above that I'd think you'd get all sorts of comb filter effects that depend strongly on location. But real life, and in real rooms, it may turn out differently.
Please let us know how it works out for you.
Will do sir. It is just going to take a while to get to that point. I'm still not allowed to walk, in fact still bed bound, and the orthopaedic surgeon said it's going to be at least another 6 weeks before I can walk without crutches. Bit of a cramp in my lifestyle, but I'll get there eventually.
Perhaps the center of the circular delay line of the upper panels gently flipped towards the head of the listener's sweet spot ?
Do you think such speakers could stand at 3 to 4' in front of the angles of a rectangular listening room - so flipped 45° towards the sweet spot - making the angles a sort of 90° dipole horn ? While it's alwas better to have absorbing surfaces, could this delay from the walls can help a little the spl limit at the cost of the dynamic (less damped sound I surmise) ??
Ferret, let us know what you'll find
... maybe the more classical ESL57 stacking concept may be enough... while singing more compressed due to its natural limited band ?Well, OT... sorry, let's go again on Acoustat dynamic (mid-bass) renforcment.
I don't have a sense for this, but it would be easy enough to try.
Linkwitz has the math worked out for a dipole -- the monopole case must have been considered. I'll flip through my copy of "Theoretical Acoustics" (Morse and Ingard) to see. If it is anywhere, it is there (or somewhere in the JAES). This would be a simple dual point-source model without baffles, which is not the real case, but it would at least give a guide on what probably is a worst case.
Linkwitz has the math worked out for a dipole -- the monopole case must have been considered. I'll flip through my copy of "Theoretical Acoustics" (Morse and Ingard) to see. If it is anywhere, it is there (or somewhere in the JAES). This would be a simple dual point-source model without baffles, which is not the real case, but it would at least give a guide on what probably is a worst case.
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