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Old 28th December 2012, 12:26 PM   #1
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Default What simulation programs cant indicate

Can simulation programs tell us how would the loudspeaker system ( combination of driver and enclosure) sound like?

Or Can we say how would the speaker system sound just by looking at the graphs generated by the simulation program (Eg. WIN ISD).
eg. the speaker system with cutoff of 40Hz. might sound muddy as well with tight and clean. can the graph generated by simulation program tell us that?

if we understand how to read the simulation program correctly probably we might be able to end up with better design.

like we most see response graph and say there is a hump, or lower cut off is so.
then delays say how would each frequency go out of phase from original. I use this information to match delays @ cross over, to avoid pockets due to phase cancletion. but I am sure what I know is just a basic. The graph speaks more and can tell more about the quality of sound. Pls help me to understand
the graphs better.
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Old 28th December 2012, 01:56 PM   #2
OllBoll is offline OllBoll  Sweden
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A simulation program can predict how the loudspeaker would measure. Your question is probably is more if we can measure how a loudspeaker sounds.
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Old 28th December 2012, 04:34 PM   #3
DUG is offline DUG  Canada
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Based (pardon the pun) on whose' ears.

Graphs will show you major problems or general trends in the sound.

Build, measure, listen, compare.

Then you will know what the graphs mean to YOUR ears.

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Old 28th December 2012, 07:03 PM   #4
sreten is offline sreten  United Kingdom
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Hi,

Sims will guarantee designs that are bad will sound bad.

What they can't tell you is how good, good designs are,
as they use small signal parameters that simply are not
true in the large signal domain, and good subwoofers
are very much large signal devices.

Sims can tell you how to manipulate the sound, but
can't tell you how good the actual drivers will be.

e.g. Xmax as a number covers a huge range of sins.

rgds, sreten.
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Old 29th December 2012, 02:33 PM   #5
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Quote:
Originally Posted by DUG View Post
Based (pardon the pun) on whose' ears.

Graphs will show you major problems or general trends in the sound.

Build, measure, listen, compare.

Then you will know what the graphs mean to YOUR ears.

Thanks but thats what we had been doing for quiet a long time. I was looking for something that would give me Idea of how louldspeaker would sound.

Quote:
Originally Posted by sreten View Post
Hi,

Sims will guarantee designs that are bad will sound bad.

What they can't tell you is how good, good designs are,
as they use small signal parameters that simply are not
true in the large signal domain, and good subwoofers
are very much large signal devices.

Sims can tell you how to manipulate the sound, but
can't tell you how good the actual drivers will be.

e.g. Xmax as a number covers a huge range of sins.

rgds, sreten.

Thanks,I agree, the travel over the xmax can never be linear so higher the spl higher are the distortions. so may be size cone sounds better,

But then there should be something different that would measure or then can be simulated. may be in measured graphs, that will say the bass is clean and tight. or clean.

ok, is there any simulation that can help in simulating distortions. I guess I have asked right. if this can be simulated, then probably
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Old 29th December 2012, 04:13 PM   #6
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Ah my friend, this is the eternal quest of speaker design, and actually all of audio.

We simply do not know what measurements are important to sound.

We can guess at a few:
- Gross distortion is not good (But low %s of various distortions may be fine. The tolerance certainly varies by individuals, and may vary with sound pressure level)
- In a speaker, big group delay is probably not good. (But again, the tolerance perhaps varies by individual, and for sure there are no fixed thresholds of "bad"). Group delay probably functions as some kind of gross correlator to time response-I wish more work was done on cepstrum analysis.
- Phase is also really just a manifestation of time response, used because time response could not be measured well back in the day. And it's still easier to measure phase.

I will state that sharp ripples in frequency response are not good, nor sharp bumps or discontinuities in the impedance curve. Those indicate some kind of acoustic mismatch. They are tolerated in some designs (i.e. horns) because those designs bring other positives to the table (high spl, sharp transient response).

sreten is correct-you can work your designs to smoothen response of frequency and time and impedance, and some packages can simulate distortion as well. But real world designs don't quite match the simulations, and always end up necessitating some kind of compromises. No speaker is ever ideal, so that's why there are so many designs.

Heck, we don't even know what is important to measure in electronics. We measure signal-to-noise, distortion, and frequency response. Yet some folks love "bad" designs like tube amps.

Basically, we don't really know what the heck we're doing. That's why audio is still an art, not a science.
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Old 31st December 2012, 02:34 PM   #7
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Quote:
Originally Posted by head_unit View Post

Basically, we don't really know what the heck we're doing. That's why audio is still an art, not a science.
Humm, This is what I always had been feeling bad about. Or I always had a feeling that the audio ( sply. speaker design ) is still more of guess work, Than a pure math .

We still need to understand lot of science behind this, once we know this. We can predict it.
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Old 31st December 2012, 09:49 PM   #8
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Just found another thread discussing what does GD parameter mean to the sound quality.
We can not hear group-delay under 100Hz?
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