R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: True or False - 1977 - Emerick hears 56kHz  (Read 4583 times)

Weird Geoff

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 58
True or False - 1977 - Emerick hears 56kHz
« on: September 12, 2006, 10:56:24 am »

The whole story about the AIR montserrat neve thing..is it possible that this story could be true..I read someplace the 1081 system didn't go above 35kHz..just wondering what you all think of that story..
Logged

JGreenslade

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 824
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #1 on: September 12, 2006, 12:11:48 pm »

True and false...

From what I understand, Neve discovered that one of the transformers in the chain wasn't terminated properly, and as such was creating a "ringing" spike around 56K

However, anyone who's looked at a tone on an FFT plot will know that - unfiltered - you will observe overtones at various divisions, i.e. in the case of 56k: 112k, 28k, 14k and so on...

Therefore, to my knowledge, it is generally accepted that Emerick picked up on the overtones that were within the 20k range.


Justin
Logged
Audio is a vocational affliction

"there is no "homeopathic" effect in bits and bytes." - HansP

Weird Geoff

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 58
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #2 on: September 12, 2006, 12:52:17 pm »

Could you expain ringing spike?

I'm technically challanged..


So you are saying that the the console can produce/reproduce (tones?) over 35kHz?

I totally get the overtone effect..I just thought..and I'm probably wrong that the complete bandwidth of the console is like ~7Hz - 35k or something..which confuses me because how can it be making 56k tones then..







Logged

JGreenslade

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 824
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #3 on: September 12, 2006, 02:18:09 pm »

Google provides a few links to the story btw: http://www.google.com/search?hl=en&q=transformer+ringing +geoff+emerick+neve+&btnG=Search&meta

In the most basic sense, signal transformers are designed to be terminated with a particular load in order to "damp" the windings. With the right measurement gear, you can actually see the windings on a transformer physically move when hit with a loud transient.

We're talking about a similar concept to loading a cartridge in a turntable set up; without the right loading, the coil will either be over-damped and curtail HF information, or without enough loading it can run away and cause excessive stylus excursion.

Have you ever put your ear to a transformer whilst it's passing a signal? They're almost akin to little speakers (hence the annoying mains-related harmonics that can be emanated into the control room).

It should also be noted that designers can toy around with the loading to create a particular effect if desired.

It's near my dinner so my articulacy is fading - let me know if this makes sense!

Justin
Logged
Audio is a vocational affliction

"there is no "homeopathic" effect in bits and bytes." - HansP

danlavry

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 997
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #4 on: September 12, 2006, 08:04:23 pm »

thermionic wrote on Tue, 12 September 2006 17:11

True and false...

From what I understand, Neve discovered that one of the transformers in the chain wasn't terminated properly, and as such was creating a "ringing" spike around 56K

However, anyone who's looked at a tone on an FFT plot will know that - unfiltered - you will observe overtones at various divisions, i.e. in the case of 56k: 112k, 28k, 14k and so on...

Therefore, to my knowledge, it is generally accepted that Emerick picked up on the overtones that were within the 20k range.


Justin


No one hears 56KHz. It is not uncommon to have some correction to some high frequency circuit also impact the audible frequencies. In fact there are some rather common mechanisms like that (aliasing, inter-modulation, beats between signals...)

I doubt it that a high frequency ringing by itself will be heard, but the decay envelope may be heard, and that is NOT ALWAYS at high frequency...

Regards
Dan Lavry
http://www.lavryengineering.com
Logged

Weird Geoff

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 58
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #5 on: September 12, 2006, 08:11:56 pm »

So is the 56kHz in question audio or elecromagnetic or what?

I was under the impression that most audio systems can't reproduce/pass that high of a frequency..I must be incorrect..


help me understand what is going on in simple terms..


I read this in Dan's "high frequency transient" thread:

"Dan Lavry"



Listning to transients:

It is a well accepted fact that even a very good ear does not hear much above 20KHz, that most mics do not pick up energy much above 20KHz, and that most speakers will not generate sound much above 20KHz. It is also well known that most of the energy generated by musical instruments is at frequencies not much higher then 20KHz.

For some reason, many ear types seem to have bought into the notion that all that I have stated above is true for some of the music, and there is also another part of the signal which they refer to as “high frequency transients”.

The concept of transient energy is well accepted by all EE’s (not just in audio) to differentiate between signals made of repetitive cycles and signals that have little or no repetition. EE's and math types make the distinction between steady state and transients (non steady state) because the math and analysis of steady state signals is simpler and easier. Non steady state analysis (transient analysis) requires much more complicated tools.

However, the non repetitive audio signal behaviour (transients) does NOT contain frequencies higher than audio. Non-repetitive behaviour DOES NOT require, imply or call for high frequencies.
The fast attack of sound, be it drum, bell or a muted trumpet may have some low energy at frequencies above human hearing. But if your system could pick 100KHz transient energy, it would certainly be able to pick up and react to 100KHz sine wave! Why bother with 100KHz energy? If you can not hear 30Khz sine wave, you can not hear 30khz transients.

The whole concept of “high frequency transient” has been repeated over and over numerous times in the audio industry, in audio magazines, in marketing material and by people intend on finding "some sort of an explanation" for various fallacies they are trying to explain or promote.

After so much repetition of that faulty concept, I would not be surprised if many ear types will simply refuse to hear what I am saying but I am stating the FACTS!

Example – “multiple choice test question”:
Which case yields the fastest voltage change you can archive with say a 22KHz bandwidth system (such as a 22KHz mic, ear or speaker)? I am talking about the steepest slop, thus the fastest changing signal.

A. 100Hz 1V peak square wave
B. 1KHz 1V peak square wave
C. 5KHz 1V peak square wave
D. 10KHz 1V peak square wave
E. 22KHz 1V peak sine wave

The 5 waves are plotted below:

http://recforums.prosoundweb.com/index.php/fa/719/0/

A. 100Hz 1V peak square wave is the red trace
B. 1KHz 1V peak square wave is the blue trace
C. 5KHz 1V peak square wave is the green trace
D. 10KHz 1V peak square wave is the purple trace
E. 22KHz 1V peak sine wave is the black trace

The fastest signal slope you can ever get in a 22KHz bandwidth system is not a transient. It is the slope of a steady state tone sine wave at the edge of the bandwidth - it is a 22KHz sine wave. The fastest signal in a 30Khz bandwidth system is a 30KHz sine wave, and so on. It is faster then the fastest transient you can create within the given bandwidth!

I know that many in audio “became attached” to that MISCONCEPTION about high frequency transients. Sorry to burst the bubble, but it is long overdue to have that nonsense cleared up. It is time to refocus on the activity to what happens WITHIN the audio band, and put an end to that fantasy about things that do not matter and things that do not exist.

If you want to test your system or your ear for "the fastest signal it can handle", go for the highest sine wave frequency within the available bandwidth. That is true for ears as well as speakers, amps and everything else.

There is no such a thing as high frequency transients extending beyond the audio bandwidth. A mic that can not capture a steady state signal above say 20KHz, can not capture transients above 20KHz. The same is true for the ear, speaker or anything else in the system. We can argue about how high an ear hears, and be sure it never gets higher then 30KHz. For most people it is well below 20KHz, be it steady state or transient energy.

Logged

Ronny

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2739
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #6 on: September 12, 2006, 11:27:25 pm »

danlavry wrote on Tue, 12 September 2006 20:04

thermionic wrote on Tue, 12 September 2006 17:11

True and false...

From what I understand, Neve discovered that one of the transformers in the chain wasn't terminated properly, and as such was creating a "ringing" spike around 56K

However, anyone who's looked at a tone on an FFT plot will know that - unfiltered - you will observe overtones at various divisions, i.e. in the case of 56k: 112k, 28k, 14k and so on...

Therefore, to my knowledge, it is generally accepted that Emerick picked up on the overtones that were within the 20k range.


Justin


No one hears 56KHz. It is not uncommon to have some correction to some high frequency circuit also impact the audible frequencies. In fact there are some rather common mechanisms like that (aliasing, inter-modulation, beats between signals...)

I doubt it that a high frequency ringing by itself will be heard, but the decay envelope may be heard, and that is NOT ALWAYS at high frequency...

Regards
Dan Lavry
http://www.lavryengineering.com


No doubt that anyone doesn't hear 56k. I don't know where the 56k came from that people keep talking about, I remember Rupert saying 54k. Maybe he's said 54k and 56k at different times.

I doubt seriously the decay envelope would be audible at that high of a frequency. Beat frequencies would take two signals, which could be possible with a miswired transformer. I think what Emmerick heard was just a higher noise floor on that channel frame and Rupert couldn't hear it. Rupert traced it down to a faux pas in the wiring and could have measured 54k from the transformer, but I'm 99% sure that Emmerick didn't hear a 54k fundamental tone.

Regarding the poster that was talking about overtones. From my understanding the fundamental frequency is always the lowest. It doesn't always have to be the loudest that humans perceive, but it's always the lowest root/harmonic. In this regard, a 54k fundamental tone will not by itself produce frequencies below itself. Any audible foldback would be a result of the components reproducing the signal, for example a transformer that isn't wired correctly. It's highly possible that Rupert didn't detect the foldback frequencies exhibited from the transformer being miswired.  
Logged
------Ronny Morris - Digitak Mastering------
---------http://digitakmastering.com---------
----------Powered By Experience-------------
-------------Driven To Perfection---------------

JGreenslade

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 824
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #7 on: September 13, 2006, 06:17:21 am »

Thinking about it, I reckon Mr Lavry's suggestion of intermod / sum/difference frequencies has to be the most viable suggestion.

I recently looked at the harmonics / overtones on an FFT plot where the sensor was being disturbed by environmental interference, and as Ronny correctly says, the overtones went upwards and not down...(fundamental @ 50hz, tones at 100,150,200 etc) Knowing this I should have suggested intermod as it's the only *viable* suggestion...

Justin  
Logged
Audio is a vocational affliction

"there is no "homeopathic" effect in bits and bytes." - HansP

UnderTow

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 393
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #8 on: September 13, 2006, 01:23:02 pm »


I read somewhere that the change to the transformer also affected the phase of the signal and that is what was audible. I am no EE so I can't say anything about the veracity or even plausibility of this theory.

Alistair
Logged

crm0922

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 272
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #9 on: September 13, 2006, 03:12:45 pm »

I think "loading" switch on the Great River MP-2NV allows one to apply or remove this loading.  I have one and you can hear a difference, but I doubt it is 56kHz!

Justin, harmonic overtones only occur at integer multiples of the fundamental.  So it is true, they will only be at higher frequencies.

Chris
Logged

Jim Williams

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1105
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #10 on: September 15, 2006, 11:27:45 am »

No one hears 56k hz, but one might sense it. I worked as a janitor in college and the classrooms had a motion sense burglar alarm running at 35k hz. I couldn't go into a room with that thing on, it drove me nuts. I always knew when it was on. The older guys couldn't sense it.
Logged
Jim Williams
Audio Upgrades

danlavry

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 997
Re: True or False - 1977 - Emerick hears 56kHz
« Reply #11 on: September 15, 2006, 02:33:55 pm »

Jim Williams wrote on Fri, 15 September 2006 16:27

No one hears 56k hz, but one might sense it. I worked as a janitor in college and the classrooms had a motion sense burglar alarm running at 35k hz. I couldn't go into a room with that thing on, it drove me nuts. I always knew when it was on. The older guys couldn't sense it.


I do not see anything in your statement about how or why you could sense it.

One can change a transformer circuit in a way that will alter the ringing characteristics, the bandwidth, the step response at 56KHz. But such changes can and in many cases will effect the performance of the lower frequencies. In such cases, it is wrong to assume that what you hear is due to hearing high frequencies.

If I were to change a transformer performance at 56KHz, and if it were to cause an audible difference, I would immediately start looking for what happens below 20KHz, along with what happens at 56KHz.

Similarly, your alarm may have introduced say 20Khz (or some other audible content) which you could "sense" while some of your friends can not. People have different thresholds and ranges...

My son can hear things that I can not. It is not surprising, is it?

Regards
Dan Lavry
http://www.lavryengineering.com    
Logged
Pages: [1]   Go Up