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AutoEQ: Automatic headphone equalization from frequency responses

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Re: AutoEQ: Automatic headphone equalization from frequency responses

#21

Post by serverholic »

ishitatsuyuki wrote: post #6
serverholic wrote: post #4

FYI, EQs will distort audio. Especially if the adjustments are large. Your average EQ will introduce phase shifts to the various frequencies that make up a sound. Linear-phase EQs don't phase shift but they also introduce pre-ringing and post-ringing effects.

Analog distortion of signals also affects the phase. A digital filter might or might not compensate for it, but it's not always bad. Also, human ears tend to be more sensitive to amplitude than to the phase. Especially if the same filter is applied on both channels, which leaves the phase difference unchanged.

It's more than just human ear sensitivity. Phase shifting changes the relationship between frequencies in a sound.

For example, phase shifting can change the amplitude of a sound. Analog hardware is especially sensitive to changes in amplitude so you might be introducing distortion just by shifting phase.

Re: AutoEQ: Automatic headphone equalization from frequency responses

#22

Post by dillondoyle »

MCllorf wrote: post #17
kohlerm wrote: post #3

it's great project. No idea why some people do not want to eq their headphones at least a little bit. It can make a huge difference. Also frequency response is IMHO at least partially a matter of taste.

from my experience, it's absolutely necessary if you listen to a lot of podcasts because every tech-illiterate podcaster dude will see an EQ setting on their microphone/recording software and think "low frequencies are manly and sound good" and boost the hell out of it, and it sounds absolutely awful. Granted my home speakers might have something to do with it, and headphones/earbuds do tend to have a high-pass filte…

Or don't even normalize. The one podcast I regularly listen too regularly has guests record over the phone or DIY and they are often inaudible (to my over used ears). That'd be a great feature on spotify if it doesn't exist

Re: AutoEQ: Automatic headphone equalization from frequency responses

#23

Post by praash »

serverholic wrote: post #4

FYI, EQs will distort audio. Especially if the adjustments are large. Your average EQ will introduce phase shifts to the various frequencies that make up a sound. Linear-phase EQs don't phase shift but they also introduce pre-ringing and post-ringing effects.

Phase shifts make no practical difference when you're equalizing headphones. You really shouldn't need to use notch filters there.

EQ phase is relevant if the dry signal has a chance to mix with the EQ output.

Changes in phase is not "distortion". When you end up making large boosts (especially to make sub bass audible), that's when your headphone drivers might start to distort sound. This is fixed with less volume, obviously.

Re: AutoEQ: Automatic headphone equalization from frequency responses

#24

Post by natdempk »

It would be interesting to compare the suggested EQ curves here vs. commercial offerings that claim to introduce a neutral response like Sonarworks. In theory I think they should be doing quite similar things, but curious if there are any real differences or if they land in the same general area.

Re: AutoEQ: Automatic headphone equalization from frequency responses

#25

Post by natdempk »

h2odragon wrote: post #18
natdempk wrote: post #16

Earlier quoted context omitted.

Yes, I know enough to know I can sweep a sine wave, but I also know enough to know it’s more complicated than that. There are various curves that affect the perception of sound volume at different frequencies, like the response of the headphones, the varying response curve of frequency perception at different volumes, the inherent differing volume response curve in your brain/ears that is the basis for stuff like LUF…

AFAIK "professional/medical" tests like 8 bands and may have put a decibel meter to their equipment this month. or not. some professional audio engineers have some special recordings they listen to on everything and use a faith based or at least difficult to quantify internal process to come up with the "right" sound. I'm more in that end of the spectrum.

Ah okay, I'm surprised there isn't something more precise and scientific out there. Interesting to know that the theoretical gold standard I would really want might not even exist.

Edit: I stand corrected, as the poster below mention (I can't reply), I'd want an audiogram from a professional. Thanks!

Re: AutoEQ: Automatic headphone equalization from frequency responses

#26

Post by mh- »

natdempk wrote: post #11
h2odragon wrote: post #7

Earlier quoted context omitted.

> a matter of taste Taste, yes; and individual circumstances. My hearing is so good it might count as a disability, but I know where I have peaks and valleys in my sensitivity and a good EQ can help with the spikes taken by tinnitus ringing from youthful big boom car stereo work and explosives. I checked their suggestions for my headphones against my EQ profile and theirs is pretty good. I like more lowfreq and much…

How can you find out where the peaks and valleys in your hearing are? I've wanted to get basically an EQ curve for my own ear hearing issues if possible as I'm sure I have some minor hearing loss, but wasn't sure how to do that. Any tips?

You can go to an audiologist that can produce this for you, if it's worth it to you

Re: AutoEQ: Automatic headphone equalization from frequency responses

#27

Post by bee_rider »

dillondoyle wrote: post #22
MCllorf wrote: post #17

Earlier quoted context omitted.

from my experience, it's absolutely necessary if you listen to a lot of podcasts because every tech-illiterate podcaster dude will see an EQ setting on their microphone/recording software and think "low frequencies are manly and sound good" and boost the hell out of it, and it sounds absolutely awful. Granted my home speakers might have something to do with it, and headphones/earbuds do tend to have a high-pass filte…

Or don't even normalize. The one podcast I regularly listen too regularly has guests record over the phone or DIY and they are often inaudible (to my over used ears). That'd be a great feature on spotify if it doesn't exist

Somebody should really make an easy-mode podcast recording app that functions as a phone call, but records the speakers locally, and then sends the audio to the host. It could even measure the latency on the call can cut that time out. This seems like it would be pretty trivial...

Re: AutoEQ: Automatic headphone equalization from frequency responses

#28

Post by mh- »

natdempk wrote: post #25
h2odragon wrote: post #18

Earlier quoted context omitted.

AFAIK "professional/medical" tests like 8 bands and may have put a decibel meter to their equipment this month. or not. some professional audio engineers have some special recordings they listen to on everything and use a faith based or at least difficult to quantify internal process to come up with the "right" sound. I'm more in that end of the spectrum.

Ah okay, I'm surprised there isn't something more precise and scientific out there. Interesting to know that the theoretical gold standard I would really want might not even exist. Edit: I stand corrected, as the poster below mention (I can't reply), I'd want an audiogram from a professional. Thanks!

You want an Audiogram from a professional. There are definitely medical facilities that can do this to a sufficient degree of accuracy.

https://en.wikipedia.org/wiki/Audiogram

Re: AutoEQ: Automatic headphone equalization from frequency responses

#29

Post by l33tbro »

bitbang wrote: post #5
serverholic wrote: post #4

FYI, EQs will distort audio. Especially if the adjustments are large. Your average EQ will introduce phase shifts to the various frequencies that make up a sound. Linear-phase EQs don't phase shift but they also introduce pre-ringing and post-ringing effects.

Depends largely on how it's implemented. There is a big difference between the quality of a well implemented convolution engine and a crappy biquad filter.

Where would something like Fabfilter fall in the scale? I imagine there's some pretty complex stuff going on under the hood.

Re: AutoEQ: Automatic headphone equalization from frequency responses

#30

Post by willis936 »

serverholic wrote: post #4

FYI, EQs will distort audio. Especially if the adjustments are large. Your average EQ will introduce phase shifts to the various frequencies that make up a sound. Linear-phase EQs don't phase shift but they also introduce pre-ringing and post-ringing effects.

The primary measurement is called group delay, which is the derivative of phase with respect to frequency (since a linear phase is just a uniform delay). Fortunately we have studies from the 70s publicly available that establish a group delay audibility threshold.

FIRs add vanishingly small amounts of distortion. Their real drawback is in the added delay. For asynchronous music playback this is nothing to worry about, but for video or anything interactive (communications or gaming) it's going to be a real tough pill to swallow.

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