[HN Gopher] AutoEQ: Automatic headphone equalization from freque...
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AutoEQ: Automatic headphone equalization from frequency responses
Author : ishitatsuyuki
Score : 148 points
Date : 2021-10-08 14:47 UTC (8 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| rokweom wrote:
| Autoeq is not just a collection of ready-made EQ settings for
| different headphones, it's also a database of measurements from
| few different review sites and a tool for creating custom EQ
| curves. Do you have a specific target that you like? You can
| create a custom curve tuned for that target. Do you want to know
| how a certain model of headphones sounds? You can make your
| current ones sound almost exactly like them. Really cool project.
| tanvach wrote:
| I created and opened up the design of a standalone DSP [1] that
| leverages AutoEQ. The DSP is optimized for our home brewed
| headphones for VR, but I've been using it for my desktop
| headphones too.
|
| AutoEQ is not a perfect tool, but an amazing (and free) starting
| point to get the most out of your audio systems.
|
| [1] https://github.com/tanvach/prettygood_dsp
| khimaros wrote:
| would it make any sense to use this for tuning a car stereo?
| particularly, to compensate for engine or road noise?
| dsr_ wrote:
| Not really. That's an immediate noise cancellation function,
| which only works (a) with headphones and (b) by recording the
| outside noise and adding its inverse to the sound being played.
| khimaros wrote:
| i don't mean necessarily doing active NC. i was more curious
| about doing an initial tune with the car at idle or while
| driving on the road as a way to compensate for the average.
| is there any value in doing something like that? maybe even
| just to tune the EQ profile of the car.
| rweichler wrote:
| If you have an iPhone X or older, you can jailbreak it and use
| EQE (https://eqe.fm) which is system-wide and has AutoEQ
| integration built-in
| londons_explore wrote:
| All this assumes the headphones are linear devices... which
| clearly isn't the case!
|
| None of these tools seem to do anything but rudimentary nonlinear
| correction... Even simple things like measuring and cancelling
| harmonics nobody seems to do...
| natdempk wrote:
| 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.
| dsr_ wrote:
| This is exactly what Sonarworks is doing, but without a
| specific software package to implement it (and sell to you).
| Bayart wrote:
| The precompiled AutoEQ/results/ tree has been a godsend, and so
| is Wavelet. I honestly would think about buying a pair of
| headphones that's not in it, unless I'm actively looking for a
| specific sound signature (but it's really all about price and
| comfort as far as I'm concerned).
| kohlerm wrote:
| 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.
| writeslowly wrote:
| I've experimented with this and the results seem to vary
| depending on the headphones. I have a set of planar magnetic
| hifimans that don't have enough sub-bass out of the box, but
| can easily make tons of sub-bass with eq adjustments. On the
| other hand, some of the other headphones I tried this on sound
| like they're just distorting more when I try to apply similar
| levels of eq compensation.
|
| There's also no way to apply a system wide eq to an iPhone, so
| you'll need an external device.
| MCllorf wrote:
| 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 filter built
| in just from their construction, so it probably doesn't affect
| everyone the same way.
|
| I've been using equalizerAPO for desktop for years. I can only
| think of a handful of content creators that don't pull that
| bass-boosting garbage anymore, so the high-pass filter pretty
| much always stays on unless I'm playing music.
| dillondoyle wrote:
| 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
| bee_rider wrote:
| 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...
| h2odragon wrote:
| > 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
| less high freq than the "flat" they're correcting for.
|
| They're offering a great resource for skipping the "what does
| this set of cans sound like" stage. I probably spent 60hr or
| more dialing these in when i got them.
| mckirk wrote:
| In which sense is your hearing 'so good it might count as a
| disability'?
| h2odragon wrote:
| https://en.wikipedia.org/wiki/Hyperacusis
|
| I don't hear "notes" and "chords", I hear frequencies. My
| range (at near 50) still goes up to where i can hear the
| bats talking. In a room with people, i cannot _not_ hear
| their pulse, breathing, and other biological proceedings...
| O_H_E wrote:
| > i cannot not hear their pulse, breathing, and other
| biological proceedings
|
| Oh WOW, that is ...... wild and interesting
| pvarangot wrote:
| I had it as a kid, went away in my teen years and now I
| only have tinnitus. For me it was only on certain
| frequencies that were boosted and they are near the
| principal harmonic of my always-there ringing tinnitus or
| in the frequency of another noise I sometimes hear that's
| more like a pure sinewave.
|
| As far as I know it's more of a brain thing and not like a
| super-ear thing.
| natdempk wrote:
| 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?
| h2odragon wrote:
| listen to a frequency generator while twiddling its dial. I
| dunno what would be the easiest tool to do that with right
| now, i'd start in audacity or some "audio programming
| toolkit".
| natdempk wrote:
| 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 LUFS. I was wondering if
| there is a correct way to do this that corrects for all
| these different effects, or something professional you
| can do or pay for to get this measured correctly.
| h2odragon wrote:
| 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.
| natdempk wrote:
| 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!
| mh- wrote:
| 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
| mh- wrote:
| You can go to an audiologist that can produce this for you,
| if it's worth it to you
| serverholic wrote:
| 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.
| bitbang wrote:
| 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.
| l33tbro wrote:
| Where would something like Fabfilter fall in the scale? I
| imagine there's some pretty complex stuff going on under the
| hood.
| serverholic wrote:
| Fabfilter isn't really doing anything magical. Its default
| mode is a pretty normal EQ with phase shifting. Linear-
| phase mode is like any other linear-phase mode with the
| same drawbacks.
| l33tbro wrote:
| Probably the UI that made me think it was a Wonka
| creation. It's really not sonically much different to a
| stock EQ.
| nitrogen wrote:
| Note that not all biquad filters are crappy.
| ishitatsuyuki wrote:
| 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.
| serverholic wrote:
| 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.
| willis936 wrote:
| 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.
| praash wrote:
| 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.
| serverholic wrote:
| An EQ that cuts frequencies can actually increase the
| amplitude of the waveform due to phase shifts. It's not just
| boosting. What I'm talking about is more relevant on analog
| gear which is more sensitive to volume.
| h2odragon wrote:
| At headphone sizes, does your DAC have a good enough clock to
| even speak about phasing?
| thih9 wrote:
| It even has settings for Apple's Ear Pods [1] (the wired
| earbuds). I remember being surprised how applying these values
| makes them resemble regular headphones.
|
| [1]:
| https://github.com/jaakkopasanen/AutoEq/tree/master/results/...
| scblock wrote:
| I would caution against applying an EQ curve to headphones
| without review beforehand. If EQ includes large boosts (which the
| example image and table shows) that can easily introduce clipping
| distortion if applied linearly without appropriate headroom
| adjustments.
|
| Additionally, depending on transducer performance large bass
| boosts may simply increase transducer distortion in the bass
| frequency. Some headphones respond well to EQ, and others not so
| much.
|
| I am not opposed to EQ, but it should be applied judiciously, and
| at least partially by ear. I don't believe trying to exactly
| match a target curve will necessarily provide good results
| compared to a more judicious approach.
| sanjiwatsuki wrote:
| AFAIK, every tool that integrates with these things apply a
| negative boost equal to the peak added to avoid clipping.
| dsr_ wrote:
| And every recommendation on the site starts with the
| appropriate amount of negative gain.
|
| But if you miss it, somehow, then setting it to the next
| whole number of decibels larger than the largest gain will
| do.
| scblock wrote:
| As an example of my point for using a judicious approach above,
| applying either of the sets of Sennheiser HD8XX measurements
| and resulting AutoEQ curves from the Crinacle and oratory1990
| folders in the Roon DSP system collapses the headstage and
| tilts the perceived tone of the headphones from relatively full
| and engaging with a dip in the 2-3 kHz region to thin and
| hollow, with an overly bright, brittle top end.
|
| Also, these are two sets of measurements of theoretically the
| same headphones, each with 10 adjustment points, some quite
| broad, some very narrow. The overall shape of the resulting
| curve for the same target compensation is similar, but they
| have some significant differences in the specifics, and they
| sound different. We have to remember that measurement systems
| and individual measurement setup can vary quite a bit, so
| settings from this tool will bake all of that in as well.
|
| As a comparison, based on review of the measured curves in more
| of a a big picture way, applying a much simpler EQ with a broad
| 1.5 dB bass lift up to about 100 Hz, another broad lift of
| about 3 dB around 2 kHz, and a slight drop of about 1 dB
| centered around 8 kHz brings the bass and vocals up a little
| but keeps headstage and overall tone intact. Maybe it's this
| particular DSP implementation, but I would be wary about trying
| to use any of the precompiled results directly. EQ can have
| real benefits, but is going to be more personal than automated
| settings will capture.
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