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

[PV Audio 5,000+ posts]

i have a question that i've been dying to know the answer to (distortion kinda unrelated).

why is it that if you increase the mms of some woofers (such as the brahma), you can get a better FR graph? what is it about adding weights to the cone that contributes to a smoother response curve? that's all. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[flakko 5,000+ posts]

do you mean a square cut off sine wave....?
I'm not sure this could be said to "cause" distortion.... IIRC that's what pink noise is generally refered to as

with amps... distortion is a different story as you move from mechanical to electrical and out of my field of knowledge though I do know some... and could have a decent discussion about this...

ya like a square wave ususally most of the time = clipped signal. but a speaker distorts due to the power being sent to it no?

i mean a clean signal wont distort a speaker until the speaker reaches its mechanical/themal limits right?

 

[stones 10+ year member]

all the things you named are generally considered things not inherent in the speaker... but something else... tinsel slap, door jams etc
distortion IMO is much much deeper than that... it's resonances in the cone, inductance, irregular and distorted reproduction

I understand what your saying but it is just so difficult to discuss the subtle quality's in amps and speakers, people have so many pre conceived notions that a discussion can quickly turn into a flame war about who's ears are right or wrong.

 

[Feandil 10+ year member]

i have a question that i've been dying to know the answer to (distortion kinda unrelated).
why is it that if you increase the mms of some woofers (such as the brahma), you can get a better FR graph? what is it about adding weights to the cone that contributes to a smoother response curve? that's all. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

depends on what you mean...

what adding Mms does is lower FS if all else is held constant

this will make the low end "smoother" at the loss of efficency (heavy loss)

this is generally the case that you'll either need a larger box... to get the same low end... or increase Mms (and lose efficency)

that's really the only thing... the smoother response isn't inherent in adding weight... it just lowers the overally efficency and therefore raises the low end output (but cutting the overall output)

 

[PV Audio 5,000+ posts]

I understand what your saying but it is just so difficult to discuss the subtle quality's in amps and speakers, people have so many pre conceived notions that a discussion can quickly turn into a flame war about who's ears are right or wrong.

you make a good point. reading books (unless they are compilations from other sources) can be detrimental to your education (in this instance i mean, not in life //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif ). if the author is claiming that, for example, lower excursion woofers offer not only more output at xmax (which is effectively a fraction of the excursion of the drivers being compared) as well as sq than higher excursion drivers, you will usually believe that. I know that i did (zaph), but if you think about it, a simple two graph argument cannot create an entire thesis, let alone a theory. What I think that this needs is experts not only on distortion, but on difficult acoustical topics in general. Then again, people are usually wise enough to avoid this forum...

 

[PV Audio 5,000+ posts]

depends on what you mean...
what adding Mms does is lower FS if all else is held constant

this will make the low end "smoother" at the loss of efficency (heavy loss)

this is generally the case that you'll either need a larger box... to get the same low end... or increase Mms (and lose efficency)

that's really the only thing... the smoother response isn't inherent in adding weight... it just lowers the overally efficency and therefore raises the low end output (but cutting the overall output)

but can you over come that by designing an enclosure that would allow the better efficiency of the "stock" driver while retaining the qualities of a lower fs? what i mean is, can you design an enclosure to have the smoothness, but also retain efficiency without other side effects and consequences?

 

[Feandil 10+ year member]

but can you over come that by designing an enclosure that would allow the better efficiency of the "stock" driver while retaining the qualities of a lower fs? what i mean is, can you design an enclosure to have the smoothness, but also retain efficiency without other side effects and consequences?

yes... but not sealed

you can easily design a bandpass/ported/transmission line that can do this

 

[PV Audio 5,000+ posts]

thanks, that's what i wanted to know //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Feandil 10+ year member]

if the author is claiming that, for example, lower excursion woofers offer not only more output at xmax (which is effectively a fraction of the excursion of the drivers being compared) as well as sq than higher excursion drivers, you will usually believe that. I know that i did (zaph), but if you think about it, a simple two graph argument cannot create an entire thesis, let alone a theory. What I think that this needs is experts not only on distortion, but on difficult acoustical topics in general. Then again, people are usually wise enough to avoid this forum...

absolutely impossible... excursion IS SPL... anyone who claims that should be instantly discounted as not knowing what they're talking about

there is ZERO inherently better about a lower excursion driver for distortion (unless it's a very wide band driver like zaph likes and IMD comes into play).... but any really wide band driver (especially small in size) will only yield VERY limited SPL and you'll actually have more IMD per db than a 2-way,3-way, or even a larger full range

 

[Feandil 10+ year member]

I understand what your saying but it is just so difficult to discuss the subtle quality's in amps and speakers, people have so many pre conceived notions that a discussion can quickly turn into a flame war about who's ears are right or wrong.

well we don't need to discuss all those subjective things cause I know they're a sensitive subject to a select few

I'm interested more in the paper part of audio.... and how people feel about that compared to their ears... and how much of what's on paper... reaches their ears //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[PV Audio 5,000+ posts]

absolutely impossible... excursion IS SPL... anyone who claims that should be instantly discounted as not knowing what they're talking about

there is ZERO inherently better about a lower excursion driver for distortion (unless it's a very wide band driver like zaph likes and IMD comes into play).... but any really wide band driver (especially small in size) will only yield VERY limited SPL and you'll actually have more IMD per db than a 2-way,3-way, or even a larger full range

http://zaphaudio.com/lowxmax.html //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[thch 10+ year member]

distortion = a signal realted to the desired signal that is not the desired signal.

linear distortion = chaning the aplitude or phase or some frequencies in the signal.

nonlinear distortion = chanigng the amplitude of the signal based upon the amplitude at a point in time (clipping/compression). also, anything else that is not simply linear.

these are the communications definitions of these things. THD and IMD are the most suited to the conversation at hand.

a square wave, accurately produced, is undistorted. of course if you wanted a square wave and get a sine wave, well, you've got distortion.

 

[squeak9798 5,000+ posts]

Sound quality is truly incredibly subjective...

Personal preference is truly subjective //content.invisioncic.com/y282845/emoticons/up2something.gif.dd110ecf3ae4b76050d87598f2f8de7c.gif

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

You can "like" +10db of bass and -10db of treble. That's your personal preference. But it will never be sound quality, no matter how "good" it sounds to you //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

That's my opinion of it all, atleast.

even with the lowest distortion driver ever made many people may not like it... it's truly amazing

Agreed. Most people enjoy their even order harmonic distortion.

But, just because certain people enjoy distortion, does that mean that lower distortion driver doesn't possess better sound quality ? Not in a personal preference sense, but in a faithfulness to the original recording sense?

 

[Feandil 10+ year member]

Personal preference is truly subjective //content.invisioncic.com/y282845/emoticons/up2something.gif.dd110ecf3ae4b76050d87598f2f8de7c.gif
True sound quality [how well your stereo reproduces the original recording], not so much.

You can "like" +10db of bass and -10db of treble. That's your personal preference. But it will never be sound quality, no matter how "good" it sounds to you //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

That's my opinion of it all, atleast.

Agreed. Most people enjoy their even order harmonic distortion.

But, just because certain people enjoy distortion, does that mean that lower distortion driver doesn't possess better sound quality ? Not in a personal preference sense, but in a faithfulness to the original recording sense?

well that's sort of the point isn't it?

is sound quality just what speaker has the lowest distortion, flattest Frequency response, etc.?

I'm inclined to agree with you that yes... this is the objective classification of sound quality

I think the discussion should intail what distortions are the worst, most offensive, and most important to remove?

IMD, non linear?

 

[thch 10+ year member]

well that's sort of the point isn't it?
is sound quality just what speaker has the lowest distortion, flattest Frequency response, etc.?

I'm inclined to agree with you that yes... this is the objective classification of sound quality

I think the discussion should intail what distortions are the worst, most offensive, and most important to remove?

IMD, non linear?

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.