perceptible audio distortion

[MooseFET]

At what point is audio distortion perceptible by the general public?

0.1% THD?  1% THD?

I googled double blind distortion, but didn't get much quantitative
data.

I will assume that you've read all the other replies and not repeat
the good points there.

Perceptible can be hard to define. At small levels of distortion,
music sounds "different" but it is hard to put your finger on what is
different about it. It can sound like it is louder than you would
like it to be or perhaps like something weird has happened to the high
end of the frequency response. These things are very subjective and
vary a lot with the type of music etc.

At something like 5% many people will say "This is distorted". It
starts to become obvious that it is distortion that is what is
different.

Below 5% people can hear the difference if you switch back and forth
between distorted and undistorted. Depending on the details of the
type of distortion, most people can hear down below 0.1% distortion.

An output stage with cross over distortion and enclosed in a feedback
loop makes the sort of distortion that is most easy to hear. When a
low frequency signal causes the output to cross through the dead band
of the cross over distortion the output does something like this:


Ascii art:

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...........*.*..**.............
...........*..**...............
...........*...................
...........*...................
...........*...................
...........*...................
...........*...................
......*****....................
....**.........................
..**...........................
**.............................


This produces a large amount of some of the higher harmonics of the
low frequency.

 

[mpm]

I never watched Sanford and Son. �Where would I hear a copy of said
tune?

I found a free streaming verion on-line, not the best quality but...
The instrument in question plays the last note of the song, and also
occurs near the beginning, in the second phrasing, about 4 measures
in.

http://hypem.com/track/385641

 

[Dirk Bruere at NeoPax]

I found a free streaming verion on-line, not the best quality but...
The instrument in question plays the last note of the song, and also
occurs near the beginning, in the second phrasing, about 4 measures
in.

http://hypem.com/track/385641

http://www.surfthechannel.com/cat/television.html

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.onetribe.me.uk/wordpress/?cat=5 - Our podcasts on weird stuff

 

[whit3rd]

At what point is audio distortion perceptible by the general public?

'Distortion' is a catchall term, so the simple measured number doesn't
correspond to a perception in a reliable way.

There was an old experiment (by Carver, reported in Stereo Review,
if I recall correctly) on crossover notch distortion, which is
a kind of harmonic distortion, in musical rendition (musical
instruments
all generate harmonics, so the distortion is 'hidden' in this case).
They found perception was reliable at 1.5% measured distortion.
They also found that listeners didn't object to this as hurting the
music, but DID have some response to 'clipping' distortion
(not sure how much).

The race to make lower distortion numbers is a marketing scam. Below
0.1%, it's unlikely to matter to a music listener. Bass distortion
in
most integrated circuit amplifiers is VERY high, and few complaints
are heard. Have a look at the LM380 data sheet.

 

[[email protected]]

At what point is audio distortion perceptible by the general public?

0.1% THD? 1% THD?

I googled double blind distortion, but didn't get much quantitative
data.

Thanks,

Michael

As others explained, it depends on the circumstances.
I do not see myself as 'general public' but there is a 'get used to
distortion'
factor too.
General public has been exposed to PWM class D cellphone songs....
give it 10% and they still like it.
I bought some cheap Chinese boxes (well 150W or so each), those
have those piezo tweeters in it...and when I switched those on, the
sound was horrible.
It is the 2 rear channels... so anyways I am used to it.
When I did put the Senheiser headphones on last week, it felt like a
relief not to hear those terrible tweeters.
So not only amp, but also speakers, and of course source material.
Way back, I think it was in the seventies, playing vinyl, Shure M44-7
element, my own designed pre-amp, huge boxes, listening for that
fine detail, elliptical stylus???
Digital came, 44.1 kHz sampling CD, and after that mp3 compression,
cellphones....
As others mentioned, cross-over is horrible, especially as it sticks
out on low volumes, clipping is a speaker killer, and somewhere in
between
zero and max undistorted sine waves, something should work.
Anyways, was just reading about some artist, Neil Young, making a case
for better audio....
It is the whole chain however, and few have the quiet living room or
workspace even to listen, for those the 80dB signal to noise is of no
use,
on the contrary, we need companders so we can listen in the car, or
next to the PC.
And with constant high volume, crossover is not so noticed, and
saves current ;-)
Conclusion?
None, let the super hifi audio freaks have their 96kHz sampling,
what not.
'General public' being converted to AAC, mp3, mp2, electronically
processed stuff in many ways.....
All depends what you want to do, remember listening in a church to
some Quad
electrostats as monitor for some flute concert, got all excited,
was much younger then, could actually hear 18kHz, and all those
15625Hz TV whistles,
could even tell you if a TV was synced properly....without looking.
The average population gets older (grey), and those high frequencies
are now used
to scare away youth that hangs around, to make secret ring tones in
class that
the teachers cannot hear, and against insects and small mammals...
Maybe older ones get deaf too (has not happened with me yet), and you
need
more and more power.. if the distortion is low enough they won't hear
it ;-)

 

[Eeyore]

'Distortion' is a catchall term, so the simple measured number doesn't
correspond to a perception in a reliable way.

There was an old experiment (by Carver, reported in Stereo Review,
if I recall correctly) on crossover notch distortion, which is
a kind of harmonic distortion, in musical rendition (musical
instruments
all generate harmonics, so the distortion is 'hidden' in this case).
They found perception was reliable at 1.5% measured distortion.
They also found that listeners didn't object to this as hurting the
music, but DID have some response to 'clipping' distortion
(not sure how much).

The race to make lower distortion numbers is a marketing scam. Below
0.1%, it's unlikely to matter to a music listener.

I used to think that about 20 years ago. Today, I would say more like
0.01% *but it all depends* on what the harmonic structure is, whether it
increases or decreases with amplitude, and many other subtle effects such
as amplitude linearity. A certain well known design has an inherent flaw
in this respect. Often the distortion is not truly 'harmonic' per se you
see, only Mr Fourier sees it differently.

Bass distortion in most integrated circuit amplifiers is VERY high, and
few complaints
are heard. Have a look at the LM380 data sheet.

The LM380 is a bad joke though. It was a joke when it was introduced.
Those'll be thermal effects most likely.

Using Nat Semi for state of the art analog IC pre and power amps look at
these.

http://www.national.com/pf/LM/LME49710.html
http://www.national.com/pf/LM/LM4702.html
http://www.national.com/mpf/LM/LM3886.html

And you can do better still with discretes !

Graham

 

[legg]

At what point is audio distortion perceptible by the general public?

0.1% THD? 1% THD?

I googled double blind distortion, but didn't get much quantitative
data.

The largest contributor to measurable distortion in a playback system
is probably still the loudspeakers, which from memory can still run
consistently above 2% for a single harmonic.

RL

 

[neon]

At what point is audio distortion perceptible by the general public?

0.1% THD? 1% THD?

I googled double blind distortion, but didn't get much quantitative
data.

Thanks,

Michael

normaly it is 3% and that is because the test involves a quick comparison.

 

[Eeyore]

The largest contributor to measurable distortion in a playback system
is probably still the loudspeakers, which from memory can still run
consistently above 2% for a single harmonic.

AT FULL POWER typically. The numbers aren't that simple. There really is
so much to it. Simple THD is almost a superficial measure now.

At average listening levels they WILL be better and some MUCH better than
others.

The clue ? You can still hear different amps sounding seriously different
even with the same speakers. Fact.

Graham

 

[Rich Grise]

AT FULL POWER typically. The numbers aren't that simple. There really is
so much to it. Simple THD is almost a superficial measure now.

At average listening levels they WILL be better and some MUCH better than
others.

The clue ? You can still hear different amps sounding seriously different
even with the same speakers. Fact.

Only if you're using your gold-plated silver speaker wires that have been
seasoned in LN2. ;-)

Cheers!
Rich

 

[Eeyore]

Only if you're using your gold-plated silver speaker wires that have been
seasoned in LN2. ;-)

Now, now. We'll have none of that audiophool chit-chat in here Rich !
;~).

God knows where those people get their ideas. Ah, they were preselected as
marketers by God in the womb. That'll be it.

Graham

 

[[email protected]]

AT FULL POWER typically. The numbers aren't that simple. There really is
so much to it. Simple THD is almost a superficial measure now.

At average listening levels they WILL be better and some MUCH better than
others.

The clue ? You can still hear different amps sounding seriously different
even with the same speakers. Fact.

Graham

Once a speaker is involved, all bets are off regarding comparing sound
since the damping factor will most likely be different between
amplifiers.

 

[Eeyore]

Once a speaker is involved, all bets are off regarding comparing sound
since the damping factor will most likely be different between
amplifiers.

Myth. The output impedance of the amp forms only a tiny part of the impedance
of the output circuit. Unless there is local feedback to the speaker terminals
themselves !

Graham

 

[mpm]

I have always wante to run the following experiment:

Gather the CEO's of all these cable companies together in a room.
Play some music using their expensive audio-fool cables.

Then, substitute those expensive cables with long strips of cut-up,
old-style, metal garbage can lids pop-riveted together to form a
suitably long enough "cable". Even better if the lids are grimey,
with a few spaghetti sauce stains here and there, or whatever...

Then, ask them to tell the difference. (Adjusting only amplitude if
needed to overcome lid loss, ohms only, not response).

I would bet you that "most" would not make the distinction any better
than random chance!

-mpm

 

[[email protected]]

I used to think that about 20 years ago. Today, I would say more like
0.01% *but it all depends* on what the harmonic structure is, whether it
increases or decreases with amplitude, and many other subtle effects such
as amplitude linearity. A certain well known design has an inherent flaw
in this respect. Often the distortion is not truly 'harmonic' per se you
see, only Mr Fourier sees it differently.


The LM380 is a bad joke though. It was a joke when it was introduced.
Those'll be thermal effects most likely.

Using Nat Semi for state of the art analog IC pre and power amps look at
these.

http://www.national.com/pf/LM/LME49...tmlhttp://www.national.com/mpf/LM/LM3886.html

And you can do better still with discretes !

Graham

For discrete circuits - where are the better amps? In Douglas Self's
books? Randy Slone's?

Thanks,

Michael

 

[Glenn Gundlach]

On Jul 26, 10:30 am, [email protected] wrote:

For discrete circuits - where are the better amps?  In Douglas Self's
books? Randy Slone's?

Thanks,

Michael

http://users.ece.gatech.edu/~mleach/lowtim/

G²

 

[[email protected]]

Myth. The output impedance of the amp forms only a tiny part of the impedance
of the output circuit. Unless there is local feedback to the speaker terminals
themselves !

Graham

We will call that your opinion. Tube amps are known for their low
damping factor since their loop gain is generally not as high as solid
state designs.

 

[Phil Allison]

Graham Stevenson

Myth. The output impedance of the amp forms only a tiny part of the
impedance
of the output circuit. Unless there is local feedback to the speaker
terminals
themselves !

Graham

We will call that your opinion. Tube amps are known for their low
damping factor since their loop gain is generally not as high as solid
state designs.


** Knew the fuckwit TROLL was gonna shift the context like that.

Facts:

Tube amps with unusually low damping factors are simply not hi-fi amplifiers
AT ALL !!! They are either guitar amplifiers or replicas of antique tube
junk from the pre hi-fi era of the 1930s or 40s.

Virtually all SS hi-fi amps have high damping factors and so do the vast
majority of *genuine hi-fi* tube amps.



...... Phil

 

[Tim Williams]

I have always wante to run the following experiment:

Gather the CEO's of all these cable companies together in a room.
Play some music using their expensive audio-fool cables.

Why? They *know* it's not the wire, it's the money. At least I would hope
most of the CEOs do.

Tim

 

[Tim Williams]

We will call that your opinion. Tube amps are known for their low
damping factor since their loop gain is generally not as high as solid
state designs.

Ironically, I get more bass from my tube amps than from a low-Z solid state
amp. These speakers are vintage Magnavox cabinets from the '50s, so the old
paper suspension midranges really resonate a lot. The bass is overwhelming
when driven with a constant-current amp (Z ~ 100 ohms)! Probably
underdamped at low Z.

Tim