There's Life Above 20khz!

http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

 

I guess that is why Pioneer put their Ribbon Super Tweeters in their HPM line from the late 1970's

 

How far up did those go?

 

The article is fascinating. I hope they do more research.

 

That's very interesting and thanks for posting. I work for a company that makes data acquisition software and hardware for the human physiological sciences and this is right up my alley.

Most Alpha waves in EEG are found when a subject is relaxed and in an eyes closed state...not asleep per se, but relaxed. This may give credence to extending the frequency range of recordings and/or equipment.

Will have to print this out and discuss with our engineering dept. next week and see what they have to say.

 

I think you are jumping to a conclusion here. Just because you get a reaction does not mean it is a favorable one. For instance if the reaction to the sound is an alarm for imminent danger, I don't think I would want that sound going off randomly in a musical piece. However if that was true and you were a sound designer on a horror movie it might be exactly what you are looking for. Of course if you are going for realism maybe just having a little bit of out of band noise is what is breaking the 4th wall with most digital recordings.

Anyway yeah very interesting stuff but I think it needs more testing.

 

And most current and previous studio gear was only good from 20 to 20 000 at best, so any ultrasonic sounds on recordings are not to be high fidelity (and may be more noise than music). So I question the wisdom of trying to reproduce them.

 

Very interesting article.

 

Those frequencies are available on albums. I was experimenting recently with LP playback methods including half-speed playback and resampling. At 33 R.P.M. the album clocked in up to 20 kHz, the sampling limit. At 16 R.P.M. the album STILL clocked in up to 20 kHz! I expected a brickwall at the top end, but it wasn't there.

 

I don't think that's a good hypothesis. You are assuming there is or might be "out of band noise" being added by the incorporation of a supertweeter. If that were true, then yes, you could expect negative reactions as well as positive. The fact is that the sounds being reproduced are simply the original intact recording. There may be some noise present, just as there is below 20k but it would be rather consistent with the "in band" noise.

What extended response in a system does is allow harmonics to pass unaltered from the recording to the listener. The extension of high frequencies even improves the linear response of the bass in my experience. The bass sounds tighter and cleaner when the supertweeters are in use. It's an odd phenomenon but one that I have heard repeatedly. It also makes the top end sound more natural, which is what one might expect.

Sounds in a natural environment do not have their bandwidth limited or their harmonics truncated and systems that do this are not doing any favors to the music. Many microphones and analog recording devices are capable of response out beyond 30k, some way out beyond that. Just because a company specs a piece of gear flat at 20-20k does not mean that it does not have capabilities beyond that unless they have been intentionally limited by filtering. Some of this equipment performs much better than others outside of the traditional 20-20k band. Much or the measuring equipment employed for audio use did not attempt to, or was even specifically limited so that it did not, measure anything outside of that band. So by incorporating wide bandwidth recording equipment, whether we can verify just how wide the band is by measurement or not, and playback equipment with similar bandwidth, we can reproduce sounds as they occurred in real space more accurately.

-Bill

 

Very interesting. Thanks for posting this, Lee.

 

Just like I always said, nothing beats the sound of live performance in a good acoustical space.

 

I read this a couple years back. Fascinating work and highly worth pursuing further, though I agree it does not yet "settle" all of the issues by any means.

FWIW I'm a big believer that what goes on above 20 kHz makes an important difference to what music sounds like. How else can one explain the very audible impact of MC cartridge loading - where you essentially are playing around with resonance peaks that are for most modern carts well beyond 20 kHz (ultrasonic range) - and yet you can clearly hear a difference in sound as you progressively increase or decrease resistance loading (even when the test is done in blinded fashion)? I can't explain WHY or HOW it happens, but I hear it happening, therefore I assume it must be so.

 

Great read, I've always been curious about that Murato ? super tweater available as an add on.

 

You are concentrating too much on the verbiage. Really everything you just said is consistent with what I was trying to convey. "Noise" just sounds like a negative word and I guess it was a poor choice of words as it might be the enemy of recording cleaning above 20kHz. I will say you have to choose your playback and recording chain very wisely if you want to avoid having mostly noise up in that register.

I was more thinking about what Mr. Diament has said with his comparisons of analog to digital and looking at the spec sheet he posted for the 192kHz ULN - which goes up to 60kHz nearly flat unlike my 192kHz which goes up to around 40kHz.

 

Now that makes perfect sense. It was unclear what you were trying to say there in general terms. I definitely find advantage in low noise preamps and in having a wide dynamic range.
-Bill

 

My JBLs with the supertweeter go up to 40kHz. Or they're supposed to anyway.

 

Hmmm, the thread has gone nearly 24 hours without any of the usual digital snipers jumping in to tell us we're all nuts and the caltech science must be wrong, and all is perfect in the most wonderful of all possible redbook worlds, etc., etc.

 

Was that an invitation?

 

You're not one of the usual snipers.

 

Shhh! Don't jinx it!

 

Perhaps they're all too busy measuring things over on Hydrogenaudio. ;-)

 

Certainly a clear sign to stay away.

 

IMHO, the greatest Pioneer speakers made! Not only did I get a freebie set of Pioneer HPM-60 speakers, but as soon as I found another set for sale locally, I didn't hesitate to buy them (and gladly paid the price)... Something about them just sounds right. My thoughts.