*Technical discussion*....what makes up distortion?

[thylantyr 10+ year member]

True sound quality [how well your stereo reproduces the original recording], not so much.

I don't buy into the 'original recording' thing. There are far too many bad

recordings to claim that we must reproduce it well to make it sound good. I often

EQ my music to compensate for bad mixes.

 

[Feandil 10+ year member]

nonlinear (THD, IMD, AHD) is an obvious issue. linear (amplitude and phase deviations) are not as important because there are ways to correct them.
you are describing the "High Fidelity" aka hifi goal in audio. hifi aims to accurately reproduce the recorded sound without any bias. it is fully objective, relegating the subjective portion to the artist and studio. because the end goal of most audio systems is the end user's happiness, the hifi solution may not be the best.

there are only 2 well defined goals in car audio -- competition SPL and hifi.

agreed about the goals....

IMD is one of those things... that while you can predict it's presence the only real way to accurately eliminate it is to split up the bandwith played between as many seperate drivers as possible, or go with a much larger speaker to produce a certain SPL to remove the excursion factor influencing and of course damaging reproduction

now you bring up phase deviations... this is something I still am unconvinced is actually distortion... not only is this generally extremely inaudible... but I don't see it actually influencing the sound quality's integrity

Are we concluding that distortion is simply anything different from the actual "written" music on that CD and what comes out and hits your ears?

if so we have some major issues I believe with that definition being widely accepted... I perhaps agree with you... but my opinion there might not matter

and what high fidelity is to one person is not high fidelity to another.... and this industry is about pleasing the consumer!

 

[Feandil 10+ year member]

True sound quality [how well your stereo reproduces the original recording], not so much.
I don't buy into the 'original recording' thing. There are far too many bad

recordings to claim that we must reproduce it well to make it sound good. I often

EQ my music to compensate for bad mixes.

ultimately I think the need arises to create a near perfect source before one is to jump to reproducing it via a speaker system...

however for now it is likely best that we concentrate on defining distortion within a loudspeaker, what's the most offensive.... heck even what speakers are the best "sounding"?

 

[goodsound 10+ year member]

one.... how does a square wave from an amp cause a driver to distort? (its on the topic of distortion right?

Its not distorting its just playing fine - thats how a square wave signal will sound. Now if you are playing a sine wave and the amplifer clips heavily (which results into kind of a square wave), then that can be called distortion.

A square wave is nothing but a rapidly alternating DC. A 100hz square wave with an amplitude of 5V means the signal switches from +5VDC to -5VDC 100 times per second and the "switch" is instantaneous.

This is different from a regular (AC) sine wave of the same frequency and amplitude because the transition from +5 to -5 would be gradual and continous.

Now a square wave might damage your tweeter but thats a different thing...

 

[thch 10+ year member]

agreed about the goals....
IMD is one of those things... that while you can predict it's presence the only real way to accurately eliminate it is to split up the bandwith played between as many seperate drivers as possible, or go with a much larger speaker to produce a certain SPL to remove the excursion factor influencing and of course damaging reproduction

now you bring up phase deviations... this is something I still am unconvinced is actually distortion... not only is this generally extremely inaudible... but I don't see it actually influencing the sound quality's integrity

Are we concluding that distortion is simply anything different from the actual "written" music on that CD and what comes out and hits your ears?

if so we have some major issues I believe with that definition being widely accepted... I perhaps agree with you... but my opinion there might not matter

and what high fidelity is to one person is not high fidelity to another.... and this industry is about pleasing the consumer!

phase distortion is a difference in the output signal that is related to the input signal. it is linear distoriton and in most cases it is inaudible, at least as long as group delay is acceptable. you obviously would notice trebel that is delayed by a full second.

distortion is a deviation in the signal that is related to the input signal. non-linear distortion is what most people think of as "distortion". these are the definitions that are used in communications systems and in engineering. possibly you want to limit the topic to only non-linear distortion? this would cover THD and IMD that exist in speakers, as well as any AHD.

you can also talk about transient distortion vs steady state distortion vs nonatonomous distortion. transient distortion is distortion present on the onset of a tone as well as the trailing end of a tone. steady state is distortion present during the majority of a contineous tone. nonatonomous distortion is a distortion pattern that is changing as the tone is played.

high fidelity is not person dependent. it is music reproduced exactly as it was played (or recorded). thus the music is reproduced without linear or nonlinear distortion, and without noise. fidelity means "truth". high fidelity is highly true to the source.

A square wave is nothing but a rapidly alternating DC. A 100hz square wave with an amplitude of 5V means the signal switches from +5VDC to -5VDC 100 times per second and the "switch" is instantaneous.This is different from a regular (AC) sine wave of the same frequency and amplitude because the transition from +5 to -5 would be gradual and continous.

square waves have no DC component. they have an excess of high frequencies compared to a sine wave of similar period.

 

[Feandil 10+ year member]

phase distortion is a difference in the output signal that is related to the input signal. it is linear distoriton and in most cases it is inaudible, at least as long as group delay is acceptable. you obviously would notice trebel that is delayed by a full second.
distortion is a deviation in the signal that is related to the input signal. non-linear distortion is what most people think of as "distortion". these are the definitions that are used in communications systems and in engineering. possibly you want to limit the topic to only non-linear distortion? this would cover THD and IMD that exist in speakers, as well as any AHD.

you can also talk about transient distortion vs steady state distortion vs nonatonomous distortion. transient distortion is distortion present on the onset of a tone as well as the trailing end of a tone. steady state is distortion present during the majority of a contineous tone. nonatonomous distortion is a distortion pattern that is changing as the tone is played.

high fidelity is not person dependent. it is music reproduced exactly as it was played (or recorded). thus the music is reproduced without linear or nonlinear distortion, and without noise. fidelity means "truth". high fidelity is highly true to the source.

yes that's correct....

I was speaking more about phase changes within a driver actually not "reproducing" the way it was recorded.... speakers have thier own phase graphs based upon frequency

for now I'd like to just define what distortion is the most offensive...

obviously we've established that non-linear is the most audible and offense and should be avoided... however of the different kinds of 1st, 2nd, 3rd, 4th, etc. harmonics is it agreed that 3rd onward is what matters?

I think discussing things like steady state distortion and transient distortion will only confuse the issue

I'm interested in what people thing sound quality is and what distortions matter.... obviously perfectly reproduced and recorded music is the ultimate goal but for something like subwoofers anything less than 5% THD is a pipe dream...

perhaps what is best .... is to pinpoint all of the different ways to have a flat BL (with advantages), progressive Cms, and try and fathom close to the ideal pistonic speaker

anyway I was more interested in what people look for in subs for distortion... and if say someone tells you this sub has the lowest 2nd harmonic distortion of any on the market would that actually matter? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[PV Audio 5,000+ posts]

what is sound quality to me? sq to me on paper is much different than in real life. i'll model out a driver to have a flat curve, steady rolloff at f3 and do everything in my power to knock down any knees or nodes that may arise. this could range from damping materials to bracing the entire enclosure. HOWEVER, once you fire it up, i usually find that i PREFER not a flat response, but a boost in the midrange and lots of attenuation in the highs. i cannot stand bright tweeters, regardless of how airy and beautiful they look on paper. i also do not like a speaker or a cone whose sole purpose is to create good all around sound. one reason i cannot stand the wilson alexandria; he made those retarded things to make any source "sound" good. however, the watt/puppy is a beast of a speaker (i like the tweeter best of anything yet) and i've been wanting to re-create it because the midrange presense is absolutely astounding, but at 16, funds are limited //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif. so i guess squeak IS correct with his definition, but the quality of the sound itself is quite different than sound preference.

 

[Feandil 10+ year member]

what is sound quality to me? sq to me on paper is much different than in real life. i'll model out a driver to have a flat curve, steady rolloff at f3 and do everything in my power to knock down any knees or nodes that may arise. this could range from damping materials to bracing the entire enclosure. HOWEVER, once you fire it up, i usually find that i PREFER not a flat response, but a boost in the midrange and lots of attenuation in the highs. i cannot stand bright tweeters, regardless of how airy and beautiful they look on paper. i also do not like a speaker or a cone whose sole purpose is to create good all around sound. one reason i cannot stand the wilson alexandria; he made those retarded things to make any source "sound" good. however, the watt/puppy is a beast of a speaker (i like the tweeter best of anything yet) and i've been wanting to re-create it because the midrange presense is absolutely astounding, but at 16, funds are limited //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif. so i guess squeak IS correct with his definition, but the quality of the sound itself is quite different than sound preference.

if you're interested in the Watt puppy (I don't particularly like it that much but at the time I heard it, a year ago I thought it was great) look at this clone of it... cost only around $500-700 in parts and your time

http://users.nac.net/markowitzgd/david/david.htm

 

[PV Audio 5,000+ posts]

thx, i'll look into this //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif