Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Aural compensator VS Loudness
Aural compensator VS Loudness
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 17th October 2020, 09:39 PM   #11
adason is offline adason  United States
diyAudio Member
 
adason's Avatar
 
Join Date: Nov 2004
Location: Maryland
I think you are scaring presscot
  Reply With Quote
Old 17th October 2020, 10:05 PM   #12
jaddie is offline jaddie
diyAudio Member
 
Join Date: Mar 2011
Quote:
Originally Posted by duncan2 View Post
If the hearing aids are digital and if somebody has analogue ones as the automatic adjustment in digital ones causes a lack of reception and audible translation by applying technical standards to an organic human being they are missing out the brains actual deciphering of audio signals .
Well, none of that actually happens because:

1. The signal entering the hearing aid microphone is purely analog. The only effective means to transduce acoustic waves to electrical signals is purely analog.

2. The signal leaving the hearing aid is purely analog. So far, there's no digital interface to the human brain.

3. The design, adjustment and performance of hearing aids is based solely on user experience and feedback. If the user experience is worse, then it's not a successful product, and fails in the market. Hearing aid patients literally do vote with their wallet.

4. All successful modern hearing aids are based on digital technology because you can't actually build in a personalized correction curve with any degree of precision with the analog technology into a device that fits inside the hear canal, and there isn't any way to perform dynamics processing effectively in that same package. All you can get out of an analog hearing aid is gain and a little very basic response shaping. All of those new digital features, and many more, are perceived by users as improvements, and are very sought-after in a rather competitive marketplace. Many assistive hearing devices include Bluetooth capability and interface rather nicely with modern smart phones. There is no way to pull that off in the analog world.

5. The design, calibration and operation of modern hearing aids is based on actual science and research, not mysticism and baloney.

I'm sorry there seems to be a gap between the real world and how you perceive a small slice of it.
  Reply With Quote
Old 17th October 2020, 10:22 PM   #13
MarcelvdG is offline MarcelvdG  Netherlands
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
A long time ago I made a simple loudness correction circuit based on the Stevens data. Much later, I saw the ISO226:2003 curves on Wikipedia and had to conclude that my circuit was undercompensating quite a bit. The equal loudness contours changed substantially in 2003, see Equal-loudness contour - Wikipedia

One thing that has remained the same is that there is not that much need for dynamic correction. With loudness control, you try to correct for the difference between the equal loudness contours at the level the recording was meant for (the level during live recording or the level during mixing) and the level you play it back at. When you subtract equal loudness contours from each other, the result depends mainly on the level difference: 100 phon minus 80 phon looks similar to 80 phon minus 60 phon.

What also remains the same, is that the very low frequencies have to be reduced by about 10 dB when you reduce the volume at mid and high frequencies by 20 dB. I used a quadruple ganged potmeter for stereo volume control (or actually two stereo fader potentiometers that I coupled in a very primitive manner) and let the unfiltered signal pass through two sections and a correction signal that only consisted of the low frequencies through only one section, so each 20 dB volume reduction led to a 10 dB bass reduction. Another stereo potmeter was used to adjust the level of the correction signal, so you could adjust the amount of loudness compensation - music that is meant to be played loud requires more compensation than music that is meant to be soft.
  Reply With Quote
Old 17th October 2020, 10:29 PM   #14
MarcelvdG is offline MarcelvdG  Netherlands
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
Quote:
Originally Posted by jaddie View Post
4. All successful modern hearing aids are based on digital technology because you can't actually build in a personalized correction curve with any degree of precision with the analog technology into a device that fits inside the hear canal, and there isn't any way to perform dynamics processing effectively in that same package. All you can get out of an analog hearing aid is gain and a little very basic response shaping. All of those new digital features, and many more, are perceived by users as improvements, and are very sought-after in a rather competitive marketplace. Many assistive hearing devices include Bluetooth capability and interface rather nicely with modern smart phones. There is no way to pull that off in the analog world.
Hearing aid dynamic range compressors were used long before hearing aids went digital. I know, because I graduated on one. There was a 2:1 dynamic range compressor with adjustable threshold and a limiter (infinite:1 compressor) meant to prevent excessively loud output levels. The compressor was also used to reduce the dynamic range requirements of the on-chip adjustable continuous-time analogue filters. Of course you can do more with digital processing.
  Reply With Quote
Old 17th October 2020, 10:53 PM   #15
jaddie is offline jaddie
diyAudio Member
 
Join Date: Mar 2011
Quote:
Originally Posted by MarcelvdG View Post
Hearing aid dynamic range compressors were used long before hearing aids went digital. I know, because I graduated on one. There was a 2:1 dynamic range compressor with adjustable threshold and a limiter (infinite:1 compressor) meant to prevent excessively loud output levels. The compressor was also used to reduce the dynamic range requirements of the on-chip adjustable continuous-time analogue filters. Of course you can do more with digital processing.
Thanks for the correction.
  Reply With Quote
Old 18th October 2020, 12:09 AM   #16
presscot is offline presscot  Thailand
diyAudio Member
 
Join Date: Jul 2010
Refer to ISO226 curve, I think an aural compensator together with a fixed loudness may be the final answer. Do you agree? The reason is the aural compensator would provide a Fletcher-Munson-liked curve, and a fixed loudness will help converting it to ISO226. Another doubt is that I heard an audio engineer once told that a correct loudness circuit should boost only bass frequency, no high frequency boosting.
  Reply With Quote
Old 18th October 2020, 01:50 AM   #17
jaddie is offline jaddie
diyAudio Member
 
Join Date: Mar 2011
Quote:
Originally Posted by presscot View Post
Refer to ISO226 curve, I think an aural compensator together with a fixed loudness may be the final answer. Do you agree? The reason is the aural compensator would provide a Fletcher-Munson-liked curve, and a fixed loudness will help converting it to ISO226.
There's no need for Fletcher-Munson. It's just wrong. ISO226 is probably as close as you need to get with possibly a bit of tweak because you don't know what level at which the mix was done.
Quote:
Originally Posted by presscot View Post
Another doubt is that I heard an audio engineer once told that a correct loudness circuit should boost only bass frequency, no high frequency boosting.
A reference to that concept is found in "Loudness Compensation: It's Use and Abuse", by T. Holman and F. Kampmann, J-AES, July/August 1978. Their conclusion was that a "loudness-derived bass tone control" was the best compromise for the time, and that's what appeared in Holman's preamp. They further concluded that the operation of the control had to involve listener subjective judgement because of the lack of specific SPL data. When that data became available several decades later, the concept of a loudness-derived, specific SPL based compensator became realizable, and found its way into Audyssey Dynamic EQ, a system for which Holman was the Chief Scientist.
  Reply With Quote
Old 18th October 2020, 01:54 AM   #18
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
Aural compensator VS Loudness
Quote:
Originally Posted by MarcelvdG View Post
Hearing aid dynamic range compressors were used long before hearing aids went digital. ...
A notorious breakthrough was Killion's K-amp:
https://www.etymotic.com/media/publi...-0067-1993.pdf

Audiometric threshold is about as described: softest tone heard in "silence". For good-hearing folks it is hard to find sufficient quiet; fortunately someone like me does not hear background 50dB up from what I heard as a youth. Oh, and in US practice the tones are ISO centers, so the lowest is 125 if not 250Hz.

The curve of smallest audible sound is NOT duplicated at medium loud levels. Nerve damage acts like an expander or "noise gate". My ski-slope hearing actually flattens-out in 80dB SPL field. This is common but far from universal.

BTW: I have an audiometer, a real-ear probe (and aid tester), a stack of books and notes, and my Noahlink programmer.
Attached Images
File Type: gif Audiogram-Me-Anony.gif (11.7 KB, 17 views)

Last edited by PRR; 18th October 2020 at 01:56 AM.
  Reply With Quote
Old 18th October 2020, 01:57 AM   #19
jaddie is offline jaddie
diyAudio Member
 
Join Date: Mar 2011
Quote:
Originally Posted by PRR View Post
BTW: I have an audiometer, a real-ear probe (and aid tester), a stack of books and notes, and my Noahlink programmer.
Too bad you're in Maine. More than a couple hours drive is out of my typical range.
  Reply to this post

Reply


Aural compensator VS LoudnessHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
D/A Distortion Compensator poynton Digital Source 8 11th April 2006 05:18 PM
Bottom octave compensator Dave Jones Multi-Way 10 28th July 2004 10:07 PM
Aural exciter modification noground Parts 0 1st April 2004 06:32 PM


New To Site? Need Help?

All times are GMT. The time now is 12:30 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki