John Curl's Blowtorch preamplifier part II - Page 3169 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th December 2012, 07:48 PM   #31681
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Quote:
Originally Posted by bcarso View Post
most professional audio reviewers have abnormal/deficient hearing,
That explain why several time, listening to a "golden star" enclosure, i was so deeply disappointed at the first second ?

About ears/measurement, i believe it would be impossible for me to build my enclosures without a Neutrik, but i had spend months to tune the level of the horn at 1/4dB, no differences on the curves, big difference with ears, as it is half the energy/bandwidth..

Quote:
Originally Posted by myhrrhleine View Post
I have tested my own hearing to 45k. I used a speaker able to go to 100k. A 15k test tone with 3rd harmonics on and off, verified with a 1/4 inch microphone and a FFT analyzer.
It is a common practice, during mixing session, to add some 40KHz peak bump to a female voice, to give some air, and everybody can feel the difference, even few dBs. And i'm not able to ear 20Khz pure sinus since a long time.
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein

Last edited by Esperado; 24th December 2012 at 08:00 PM.
  Reply With Quote
Old 24th December 2012, 08:44 PM   #31682
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
I see only an issue when calibrating speakers only with measurements - the ear is not a microphone

Harman is one of the few if not only manufacturer that takes listening tests very seriously, and uses a panel of trained listeners, blind tests and has developed some good software to teach how to listen.
Link to a public beta is on Sam Olive blog (I'm on phone and don't have link at hand but google will do)
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938

Last edited by Telstar; 24th December 2012 at 08:46 PM.
  Reply With Quote
Old 24th December 2012, 09:29 PM   #31683
fas42 is offline fas42  Australia
diyAudio Member
 
fas42's Avatar
 
Join Date: Jun 2012
Location: NSW, Australia
Blog Entries: 11
Quote:
Originally Posted by scott wurcer View Post
I certainly am willing to entertain the possibility that the leading edge of transients can shift in localization. I definately have heard the sibilant sounds on instruments have an off image "noise" component added. OTOH I have perfectly enjoyable CD's and LP's of traditional Japanese instruments.

BTW - These instuments make sense as being right there in the room with you (as does solo acoustic guitar), I find almost any recorded examples to be so far from the reality I would probably look for something more fundamental wrong.
Getting the leading edge of the transients right is essential, but most systems distort too much on playback to sound "correct". Nothing wrong with the recordings, the failure is on the end consumer's side - in the effort to not have the reproduction too abrasive for a high percentage of recordings the sound is so dulled or "politisized" that very little playback ever hits the mark ...

BTW, Merry Christmas to all! ...

Frank
  Reply With Quote
Old 24th December 2012, 09:44 PM   #31684
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by myhrrhleine View Post
I have tested my own hearing to 45k. I used a speaker able to go to 100k. A 15k test tone with 3rd harmonics on and off, verified with a 1/4 inch microphone and a FFT analyzer.
I've done some of the brickwall filtering tests myself, I personally can't hear a 17kHz brickwall applied to music (IIRC a pretty nice set of Prokofiev string concertos) so I don't bother being a subject in these tests. But I thought we started talking about folks who could not hear anything but their brains were working on it.

I've spent years designing experiments for problematic circuits and customer applications and acoustics is very problematic, the quality of instrumentation for sound pressure is so far behind that for voltage and current (for instance) that the room for error is large. LP's, speakers, and microphones are orders of magnitude worse for IM and FM than precision electronic instrumentation.

Happy holidays to all, I manged to get all but one kid and my buddy Otis together here in SF.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."

Last edited by scott wurcer; 24th December 2012 at 10:05 PM.
  Reply With Quote
Old 24th December 2012, 10:36 PM   #31685
diyAudio Member
 
Join Date: Nov 2011
Location: Cooktown, Oz
Quote:
Originally Posted by bcarso View Post
Candidates for loudspeaker evaluation at my former client Harman's facility undergo hearing tests beforehand. The little secrets that emerge: most professional audio reviewers have abnormal/deficient hearing, and their evaluations are usually less internally consistent than even those of untrained listeners. The consistency of the responses from trained listeners is remarkably good.
I can second that. My little contribution to BlindLeaks is that the top speaker designers in the known universe all have some hearing affliction or other.

But they can all lip-read speakers behind a black curtain.

I'm not sure the usual hearing loss with age precludes a subject from being a true golden pinnae except for severe cases and for special tests like audibility of supersonics.

"Professional audio reviewers" with one or two notable exceptions perform badly compared to the general public. Jane Public is significantly better than Joe. But the consistency of responses from the public is remarkable. The key is removing stress.

We never did hearing tests on subjects BEFORE a listening test but would test those who did well in the Blind Listening Tests. Our 'formal' panel was tested at least once a year.
Quote:
Harman is one of the few if not only manufacturer that takes listening tests very seriously, and uses a panel of trained listeners, blind tests and has developed some good software to teach how to listen.
Wharfedale did this from the late 70's. The Pseudo Prophets Floyd & Olive quote Peter Fryer in their pontifications. I simplified, refined and improved these tests over nearly 2 decades and in the process was privileged to work with some of the best ears in the business.

Excuse my obvious NIH syndrome when discussing Floyd/Olive. Since Wharfedale became a box stuffer, Harman are probably the only maker attempting to use Blind Listening Tests as a design tool today so deserve recognition. Most of their stuff is good though I can laugh at some of their methods.

Standing back as far as I can, my main criticisms are
  • not paying enough attention to reducing stress. I only know what they have published so they may have addressed this
  • their tests are obviously not designed by speaker designers
  Reply With Quote
Old 24th December 2012, 11:31 PM   #31686
diyAudio Member
 
Join Date: Nov 2011
Location: Cooktown, Oz
Quote:
Originally Posted by gpapag View Post
Do you remember the frequencies and slopes of the band limits and where the filtering was applied in the reproduction chain?
This was done circa 1980 with vinyl & mastertapes we cadged off the record companies.

One of the recordings was the famous early Blumlein stereo Beecham Scheherazade from EMI. I was always unimpressed by the vinyl but the mastertape was a revelation.

Bandlimiting was by brickwall passive analogue filters at 20kHz; essentially souped up multiplex filters. In fact the first trials were with multiplex filters screwed up to their limit. Peter Wall could do supa dupa passive filters the old fashioned way. I grovel at this feet.

As a speaker & microphone man, I can pontificate at length on the reasons for the preference for band limiting but the intermod that Scott & others have pointed out is probably the main cause.

The reason for these tests was prompted by some inconsistency in doing other audibility tests.

In the 90's, we considered repeating the tests with better source material but by then, all high quality sources were evil digital and already bandlimited. This makes life a lot easier for playback electronics.

The results are exactly applicable to Golden Pinnae today with their MC cartridges & vinyl ... but I'll stick my neck out and suggest that if these tests were repeated on true SACD (no evil PCM masters issued on SACD), the preference will still be for Bandlimiting.

The issue isn't whether certain people can hear supersonics. It's easy (??) to devise test signals that allow certain individuals to detect supersonic signals ... and leave them with a headache for the next 24hrs.

The issue is whether they can be heard on music. And if the answer is yes, do these listeners prefer their music with supersonics?

To answer these two questions, the tests MUST be Double Blind as the expectation bias in both camps is extremely high.

But the definitive lesson on how a Bandwidth Limitation Test should be conducted is from Harry O, The experiment that saved high fidelity

In the forseeable future, it's likely Bandwidth Limitation will be preferred by those who can tell the difference ... until us evil speaker & microphone designers get our act together

Last edited by kgrlee; 24th December 2012 at 11:42 PM.
  Reply With Quote
Old 25th December 2012, 08:27 AM   #31687
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Good contributions, kgrlee. Thanks and merry Christmas
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 25th December 2012, 09:05 AM   #31688
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by scott wurcer View Post
I've done some of the brickwall filtering tests myself, I personally can't hear a 17kHz brickwall applied to music (IIRC a pretty nice set of Prokofiev string concertos) so I don't bother being a subject in these tests.
As documented somewhere in the NL AES section at LinkedIn we did some controlled listening tests with the 15kHz brick wall filters used in FM stereo multiplex encoders.
Out of 4 listeners, 3 could hear differences at 100% reliability with/without the filtering (the fourth person stated he could not hear it and did not participate further).
All three we preferred the music with the filter...

Merry Christmas, Happy 2013 to all, and here's some live music for you.

jan
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W. S. Maugham
Check out Linear Audio!
  Reply With Quote
Old 25th December 2012, 11:55 AM   #31689
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Merry Christmas for all of you.
Applying the Bonsai error correction's idea, i made myself a gift. What do -you think of that ?
Attached Images
File Type: gif error-corr-res.gif (74.0 KB, 160 views)
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein
  Reply With Quote
Old 25th December 2012, 03:19 PM   #31690
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by jan.didden View Post
As documented somewhere in the NL AES section at LinkedIn we did some controlled listening tests with the 15kHz brick wall filters used in FM stereo multiplex encoders.
Out of 4 listeners, 3 could hear differences at 100% reliability with/without the filtering (the fourth person stated he could not hear it and did not participate further).
All three we preferred the music with the filter...

Merry Christmas, Happy 2013 to all, and here's some live music for you.

jan
Did they check for any 19kHz pilot issues?
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 06:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2