System that sounds so real it is easy to mistaken it is not live

@esputnix my one jaw drop moment was taking a tour of Mechanics Ha in Worcester, MA. First we were in the hall itself, then we went upstairs to their highly customized remote listening area with B&W 801s just outside the mixing booth upstairs. The walls were specially treated and the room was packed with people. Because we had just left the hall our ears were accustomed to its acoustics, so when they played a live recording it seriously sounded like w and a requsst in right in front of the orchestra. It was magical. I've never heard anything like it since, but if you have the opportunity to travel, ask them if they can arrange for a tour so you can hear what I heard. 

 

They played 

@lewm , thanks Lew. That is a common subwoofer mistake, crossing over too low. The makers of commercial subs using just a low pass filter suggest that but, it does not clean up the main speaker as much. Info below 40 Hz is relatively rare. If you can see the cones of the subwoofers moving then Doppler distortion is at play not to mention the non linearities you get into on far excursions. If you play test tones you can easily see the cones moving up to about 100 Hz. This is double important on ESLs because the driver is full range. When dealing with a dynamic speakers it will only be the range of the woofer that is cleaned up. This is still substantial in most instances. This mandates a complete two way crossover. I am also talking about digital crossovers which are a benefit as delays can be adjusted so that the signal arrives at the listening position at the same time in phase. The best location for dipoles in the room is never the best location for subwoofers. It is not easy to make subs blend in with 8 foot tall ESLs. It is not the dipole nature of ESL that creates the conflict but rather the line source characteristics. It requires a line source subwoofer especially if crossing up higher. As I previously mentioned Dr West is aware of all of this but he has to sell loudspeakers to survive and many people do not want to get involved in loudspeakers that require subs. Jim Strickland of Acoustat was the same way, maybe worse. He stubbornly refused to admit his speakers benefited from subwoofers. 

We once calculated that my speakers have about 400 in.² greater radiating area then do yours. Perhaps that’s where our results differ, because my speakers are not perceptibly distorting in anyway at 100 Hz. And there is the added value of coherence and continuity with higher frequency music. Now you are saying there is no point in reproducing music below 40 Hz, because there is not much information. Isn’t that contrary to your previous assertions about your system going down to 15 Hz or thereabouts? Why do you bother to be concerned about frequencies below 40 Hz, if they are irrelevant? I say this Not as someone who believes that frequencies below 40 Hz are irrelevant.

I remember a blind test in the 80s where blindfolded listeners compared live performances with recordings of the same music in the same space.  The results were strong; most listeners were able to distinguish easily and reliably.  Even $1,000,000 systems have a long way to go.

These tests should be repeated.

It is also easy to run blind tests of components.  Set up two identical complete systems in the same space.  Insert the two components to be tested in the systems.  Play the same recordings A B X, where blindfolded listeners are to identify X as A or B.  Repeat say 10 times.  Score the number of successes against the probability of the result being chance.   For sticklers re-run the test with the common system components swapped out.  Golden ears should be very afraid, but these tests should be run to establish whether they have any worthwhile credentials.

 

Dear @mijostyn  :  " The surrounds corroded and they literally fell apart. I can not quote you figures but I do know that given appropriately large drivers in well constructed sealed enclosures distortion levels are easily under 0.5%. It is only when using smaller drivers in flimsy enclosures that distortion becomes a problem.  An amplifier that has tight control over the driver like the JC 1s with their damping factor over 1000 will result in excellent performance far in excess of what any Class D plate amplifier can provide assuming a large driver in a well constructed enclosure of which there are very few. The Velodyns do not qualify as a well constructed enclosure. No commercial subwoofer excepting the Magico Q series qualifies.  "

 

Which Velodyne you own for 10 years?, mines I think has even more with no single problem " the surrounds corroded.

 

"  I do know that given appropriately large drivers in well constructed sealed enclosures distortion levels are easily under 0.5%. "

 

I disagree with you till you,please , share 2-3 names where that is happening. In the case of my Velodyne what permits that the THD be as low as 0.5% is that as I posted Velodyne is monitoring the woofer excursions over 16K times each second. My velodyne is self powered by a class D amplifier, here some specs:

"""" 

• High quality crossover system
• High Gain Servo System
• Selectable subsonic filter (15/35Hz)
• Infrared remote control (optional)
• Adjustable low-pass filter
• Subwoofer Direct crossover by-pass
• Phase adjustment
• XLR-Connector
• Auto On/Off

Amplifier: Class D 1250 Wrms (3000 W peak)
Woofer: 15" forward-firing (12.7" piston diameter)
Voice Coil: 3" Dual Tandem push-pull
Excursion: 2" maximum
Magnet Structure: 380 oz  (24 lbs)
High Pass Crossover: passive 80/100Hz (6db/octave filter)
Low Pass Crossover: 40Hz-120Hz (12db/octave initial; 48dB/octave ultimate)
Crossover Bypass: Yes - subwoofer direct
Anti-clipping Circuit: Yes.

 

As I posted my units position are not firing directly to the seta position and not between the main speakers but  side firing in between seated at 15cm.-20cm. from the floor just in front of each speaker and have in the top plate a a 40kg. dead weigth.

The subwoofers were modified in its amps, input electronics and the woofers rewired with KK KCAG cable. I'm so demanding in my system that when we analized the input electronics not only modied but we took in count that the shortest signal path is not at its RCA input but to the balnace input and where are connected. By a " detail " on something similar my ML 20.6 modified monobloks are connected directly to the amps mother board inputs not in the balanced way but in the shortes path: single ended.

 

Btw, the Velodyne construction makes its job, at least my  now " vintage "units.

 

 

"" When dealing with a dynamic speakers it will only be the range of the woofer that is cleaned up. ""

 

Not really because when you cleaned up the woofers ( as in my ADS high pass filter ) and lowers its IMD then the mid-range and high frequencies really shines as never before due that the woofers " dirty " harmonics already gone ! ! and this is the main issue about.

 

Only Magico, really? Today there are several good options and in the past I had the opportunity tolisten the Krells subs self powered by Krell special dedicated class A amps and listened to the Wilson Audio. Both great units.

Btw, thank's for your offer but rigth now I'm fine about.

 

I forgot to mention that with and with out subs the top SL are a little " short " in its overall quality lwevel than my ADS system

TYhe best planar speakers other than SL were the Apogge and inside its line the Scintilla,  Magnepan middle line with subs. For me Ribbon are a little better than electrostatic designs.

 

I return my subs to 80hz crossover, 95 hz just does not works for me.

 

R.