Sound Quality Vs. Measurements - Page 460 - 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 21st April 2012, 06:44 PM   #4591
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
It just struck me that Thorsten and I have come a full circle, in all this talk of bias levels.

Thorsten says more bias reduces high frequency distortion, which ellegantly brings us back to the basic question - yes, it can be mesured, he did measure it, but exactly how relevant is this to what we hear?

Will reducing 50 kHz distortion from say 0.4% to say 0.2% actually yield better sound as we hear it? Will we HEAR the difference?

An interesting question. I suppose the only way to know for sure is to make a sample and try both versions, say 130 and 230 mA, listen to what happens under actual, real life conditions.

I THINK (but do not know for sure) that 230 mA will not yield any audible improvements over 130 mA, or, if it does, it will be a minscule improvement. But as I sad, the only way to KNOW is to try it.
  Reply With Quote
Old 21st April 2012, 06:52 PM   #4592
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by dvv View Post
Will reducing 50 kHz distortion from say 0.4% to say 0.2% actually yield better sound as we hear it? Will we HEAR the difference?
I could see where IM from quadratic nonlinearities would throw material down into regions of high aural acuity, if there is a lot of ultrasonic energy in the signal.
  Reply With Quote
Old 21st April 2012, 06:54 PM   #4593
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by a.wayne View Post
HiFi no , life like realism ......True dat ..........
For life like realism, good buddy, you also need to have a front end capable of it, and a back end (speakers) capable of reproducing something like 114 dB SPL in peaks.

And the size and furnishing of your room are also highly relevant factors.

Personally, I just made it. I have a small room, some 14*12 feet, fairly full of everything. My speakers do 92 dB/2.83V/1 m, and my Karan amp is rated at 180/250W into 8/4 Ohms. 180W/8 Ohms works out to 22 dBW, plus a single speaker's efficiency of 92 dB equals 114 dB. Two speakers in tandem will of course increase the actual SPL, but the room will soak up some of it, so let's assume I'm even on that point.

My point is, I know from first hand experience excatly what you are saying. But I must now dissapoint you - in real life, peaks of 114 dB are EXTREMELY rare, and I do believe 99.9% of all audiophiles have system which don't even get near that, yet play music very well. Also, both the HK 680 integrated (rated at 85/130 W into 8/4 Ohms) and the Marantz 170 DC power amp (rated at 85/8 Ohms) are extremely convincing in ANY reproduction.

Ah, if it all boiled down just to power ...
  Reply With Quote
Old 21st April 2012, 06:56 PM   #4594
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by bcarso View Post
I could see where IM from quadratic nonlinearities would throw material down into regions of high aural acuity, if there is a lot of ultrasonic energy in the signal.
Agreed - but the key word here is "if".

We all know that may happen, but we also all know it shouldn't happen. What's a CD/SACD player, or FM tuner, doing passing out 50 kHz signals? Should the amplifier now be charged with duties of mopping up after some other lemon in the system?
  Reply With Quote
Old 21st April 2012, 07:00 PM   #4595
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Dejan,

Quote:
Originally Posted by dvv View Post
Thorsten, let's talk some statistics.
Let's, I did major work on stats for my second degree.

Let me give some stats of my own.

First, 99% of all statistics are made up on the spot...

Second, I only trust statistics I have faked myself...

Quote:
Originally Posted by dvv View Post
About 99% of the current class AB amplifiers use less than 80 mA per output pair.
They probably also use more than 0.22R emitter resistors.

Quote:
Originally Posted by dvv View Post
No automatic system is foolproof.
I cut my teeth in my original praktikum on complex electronics intended to help fools who would neither train adequately nor Read The Fantastic Manual (RTFM) to still hit the target. After that I spend time in inductrail electronics (operators are usually fools and if you do not block them the costs of foolishness are high) before moving into pro audio and eventually into financial computer systems (you would not believe the fools you find in accounting)...

I may not be able to make the system foolproof, but heck, I'm the operator and I ain't no fool, just a bit "schräg"... :-P

Quote:
Originally Posted by dvv View Post
You will of course do as you please, but I would advise you keep it on a constant level, even if it is elevated in comparison with the average. Keep it simple and ellegant, is what I say.
I do not disagree, but as we do not live in ideal world...

I think I go 2-level and use a lockable (my 2 YO Daughter otherwise may throw a spanner) toggle on the front panel.

Quote:
Originally Posted by dvv View Post
Use the minimum you have to use to achieve your goals, but no less. And no more.
My goals are differentiated and multidimensional... It may take more than simple bloodymindedness (I am good at simple bloodymindedness though).

Ciao T
  Reply With Quote
Old 21st April 2012, 07:08 PM   #4596
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by dvv View Post
It just struck me that Thorsten and I have come a full circle, in all this talk of bias levels.

Thorsten says more bias reduces high frequency distortion, which ellegantly brings us back to the basic question - yes, it can be mesured, he did measure it, but exactly how relevant is this to what we hear?
Good question. I use traditional terminology to express radical ideas.

My prior point was that what we "hear" are not individual harmonics but in essence the transfer function composite. We are gaining much better understanding of the concept.

For example, a "transfer function curvature" which gives rise to only low order harmonics is not objectionable, if at all audible, yet an opposite one may have much lower THD and yet be much more objectional on audibility, DESPITE the individual harmonics lying below the system (including listening room) noisefloor.

So I am rendering a newish concept in traditional terminology, rather than following the lead of L Ron & Scientology in just making up new volcabulary.

Ciao T
  Reply With Quote
Old 21st April 2012, 07:10 PM   #4597
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by bcarso View Post
I could see where IM from quadratic nonlinearities would throw material down into regions of high aural acuity, if there is a lot of ultrasonic energy in the signal.
I use Non-Filtered DAC's with sample rates up to 192KHz (but thankfully for the Amp's not SACD with around +10dB RF noise compared to signal levels) and LP. DMM LP's have a very high frequency pilot tone to make cutting easier, it is near -6dB IIRC.

Ciao T
  Reply With Quote
Old 21st April 2012, 07:12 PM   #4598
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Hmmm. Spice of the modified Hafler shows a drop at 50K with .154 V in from .19 to .17% At full power, ( 1.54 in) drop from .11 to .09%. At 1K and .154 in, it is some difference between .0000 something which I consider highly incorrect in the real world and most likely irrelevant. This is from the 110 it is set at to 250 ma. Audible? I plan on this test next time I set up for my wife to listen. She has not heard my Creek in the test. I am most interested in that. The .4 and .2 numbers are probably a lot more realistic.
  Reply With Quote
Old 21st April 2012, 07:14 PM   #4599
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by dvv View Post
Agreed - but the key word here is "if".

We all know that may happen, but we also all know it shouldn't happen. What's a CD/SACD player, or FM tuner, doing passing out 50 kHz signals? Should the amplifier now be charged with duties of mopping up after some other lemon in the system?
FM Tuners have 19KHz pilot at very high levels and a barely suppressed 38Khz pilot that makes it through the Stereo decoder.

DMM LP's utilise a > 50KHz pilot at near full level to make cutting in solid copper easier (kind of like these vibrating shavers).

SACD has around 10dB more HF noise than signal.

Traditionally filtered CD lacks high frequency stuff, remove the filter, another story...

Ciao T
  Reply With Quote
Old 21st April 2012, 07:19 PM   #4600
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Some years ago, I recall Keith Johnson warning, at a presentation about DSD at an AES convention when he got the microphone, that these signals were going to get a lot of amplifiers in trouble. And at that, the Spectral amps were famously wide bandwidth (do I recall 2MHz? You could have a pirate radio AM station if you had room for a decent antenna ).
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Quality Control differences = variations in sound quality? KT Class D 3 4th June 2014 12:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 08:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 09:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 03:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 03:02 PM


New To Site? Need Help?

All times are GMT. The time now is 09:36 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