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Is PEQ transparent?

Chester

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Assuming (maybe incorrectly) that parametric EQ offers the best quality, can it be considered audibly transparent in terms of things like noise introduction etc? Obviously it changes the original signal so I don’t mean transparent in that sense.

Also, can PEQ be measured in the same way other things can, like sinad for example?

And if it can, is there any data out there for the main PEQ offerings, like Roon? If so, who does it best?

Apologies for the amateur questions, I couldn’t find much info when researching these questions.

Thanks
 

MaxBuck

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I imagine any device used for PEQ poses the potential for distortion and noise. The idea is to select equipment that minimizes the negative effects. Pretty much like any other component.
 

LTig

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Yep. It's a balance between improving the sound through EQ vs addition of noise and distortion. If the EQ is on the digital side I would not worry about the latter. Just let your ears decide which you prefer: better FR with noise and distortion or bad FR without.
 

Jimbob54

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Assuming (maybe incorrectly) that parametric EQ offers the best quality, can it be considered audibly transparent in terms of things like noise introduction etc? Obviously it changes the original signal so I don’t mean transparent in that sense.

Also, can PEQ be measured in the same way other things can, like sinad for example?

And if it can, is there any data out there for the main PEQ offerings, like Roon? If so, who does it best?

Apologies for the amateur questions, I couldn’t find much info when researching these questions.

Thanks

I'll let others answer on the technical perspective of how and what to measure but my understanding from reading around on here is that the DSP/ PEQ itself should introduce very little to no audible artifacts simply by being in the chain. Thats not to say the way the frequency response is changed wont have significant impacts downstream on amps and/ or transducers but I wouldnt worry about the impact of the processing itself on the sound. I'd focus more on how to integrate it into your system as easily as possible , so interfaces and ability to use in your chain are probably far more important these days .

So for example Roon is costly but great interface but will only work on local files, Tidal and Qobuz so of no use to users of other services. I dont believe the way it's DSP operates is inherently better from a sound quality perspective than say Equaliser APO on Windows which is free and system wide.

Edit but don't take my word for it, Don actually knows what he is talking about https://www.audiosciencereview.com/...-floating-point-explanation.25109/post-852913
 
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RayDunzl

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Assuming (maybe incorrectly) that parametric EQ offers the best quality, can it be considered audibly transparent in terms of things like noise introduction etc?

Digital PEQ - transparent

Analog PEQ - it depends
 

dfuller

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It depends! Minimum phase introduces some phase shift (which is largely inaudible, unless you're using very steep pass filters as crossovers and not compensating for the delay) and post-ringing, which can be audible if the Q is tight enough and the gain is high enough (positive gain on an EQ is a resonator in phase with the signal, essentially). Linear phase doesn't introduce phase shift, but it does introduce pre-ringing which can be audible at low frequencies if the filter is steep enough - and this is much more audible than post-ringing.

Dan Worrall demonstrates this very well with FabFilter Pro-Q, which is an excellent digital PEQ with both linear and minimum phase available.


The other thing to note of course is that if you're using a hardware PEQ, then you have whatever noise and distortion that box introduces.
 
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Chester

Chester

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Thanks all for your responses, very helpful.

So are most digital PEQ offerings essentially the same or do some use less destructive approaches than others?
 

Jimbob54

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Thanks all for your responses, very helpful.

So are most digital PEQ offerings essentially the same or do some use less destructive approaches than others?
If you havent already seen it https://www.audiosciencereview.com/...ows-linux-macos-ios-ipados-and-android.18450/ this might have some more on some of the questions you have.

I think your best bet is trial some of the solutions and see what you think. I wouldnt worry about any software solution being destructive as it is entirely removable if you dont like it.
 

Purité Audio

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If you stick to correcting only minimum phase regions of the response then you will achieve a perfect inversion, ie no delay, you can check which regions are minimum phase with REW.
Keith
 

Burning Sounds

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It depends! Minimum phase introduces some phase shift (which is largely inaudible, unless you're using very steep pass filters as crossovers and not compensating for the delay) and post-ringing, which can be audible if the Q is tight enough and the gain is high enough (positive gain on an EQ is a resonator in phase with the signal, essentially). Linear phase doesn't introduce phase shift, but it does introduce pre-ringing which can be audible at low frequencies if the filter is steep enough - and this is much more audible than post-ringing.

Dan Worrall demonstrates this very well with FabFilter Pro-Q, which is an excellent digital PEQ with both linear and minimum phase available.


The other thing to note of course is that if you're using a hardware PEQ, then you have whatever noise and distortion that box introduces.

Excellent post, and the Dan Worrall video is one of the best I've seen at explaining the difference between linear and minimum phase.

I've mentioned this before in other DSP related threads, but worth repeating here. If you try to compare different DSP software by inputting the same filters they may not sound the same. This has nothing to do with transparency, but because of the way they implement Q. JRiver and Roon are two examples of this. Whilst peaking filters are the same for JRiver and Roon, shelving filters are not.

Rane have an old but still useful DSP note explaining this: https://web.archive.org/web/2012111...tes/Why_DSP_Boxes_Set_the_Same_Way_Differ.pdf

Also this post might help too: https://www.audiosciencereview.com/...-ipados-and-android.18450/page-11#post-841229

Edit: updated link to Rane notes - looks like it is only available on the Wayback Machine now.
 
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Matias

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I use linear phase (fir, convolution, I don't really know the difference) to keep phase constant, and upsample to very high sample rates to minimize pre ringing. A normal PC can handle the workload nicely, but the dedicated hardware devices usually cannot...
 

RayDunzl

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GaryH

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For headphones, which are almost always minimum phase devices, you'll want to use minimum phase PEQ filters. As Oratory explains:
Oh yeah, many people fall for that trap, believing that digital filters are the only thing that affects phase, and that it should therefore be avoided meaning linear-phase filters (which can only be done via FIR filters) are clearly superior.
Well, this point of view is very much wrong.
Any change to the frequency response will always go hand-in-hand with a correlated change in the phase response!
And by "any" I mean "anything that isn't a digital FIR filter where FR and Phase Response can be separated from each other with mathemagic".
TL;DR:
IIR filters are fine and are actually exactly what you want when the goal is to "fix your headphone's flaws".
So if you want to fix a certain flaw in the frequency response of your headphone, this flaw will also show itself in the phase response, and by using a minimum-phase-filter ("a normal filter") you will fix both these things at the same time.
 

threni

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Digital PEQ - transparent

Ideally, perhaps, but surely it depends on the implementation? Would be interesting to see a comparison of some of them.
 
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