[HN Gopher] Show HN: HiFiScan, a Python app to optimize your lou...
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Show HN: HiFiScan, a Python app to optimize your loudspeakers
Author : erdewit
Score : 207 points
Date : 2022-09-11 11:59 UTC (11 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| ttpphd wrote:
| I'm a psychoacoustician and this is not the way, very sorry to
| report. Others have touched on the acoustic issues already, so
| let me touch on the psychological ones: your perception of sound
| from loudspeakers doesn't just depend on the acoustic waves
| hitting your ears. It also depends on your personality and
| expectations. If you genuinely believe that doing a seance to
| drive out the poltergeist from your speaker set up will make the
| sound better, it will be difficult to convince you otherwise
| precisely because the acoustics did not actually perceptibly
| change.
| stdbrouw wrote:
| "Frequency response does not matter because other things also
| matter and I have a PhD in these other things." This is a
| complete non-argument.
| kekebo wrote:
| It's an unwritten rule in the studio scene around me to have a
| specific fader that is prominently placed but does nothing. To
| use when certain musicians (usually guitarists) demand to raise
| the gain of their instrument into unreasonable territory. Seems
| to work reliably to look at them and very slowly raise that
| fader until the they say it's good
| bityard wrote:
| > If you genuinely believe that doing a seance to drive out the
| poltergeist from your speaker set up will make the sound
| better, it will be difficult to convince you otherwise
|
| I think you just found the next big thing in audiophile fads
| willismichael wrote:
| I'm more interested in inviting the right kind of poltergeist
| to dwell in my speaker set up, to give playback the warm
| paranormal sound that is clearly missing from sterile
| exorcized speakers.
| aeturnum wrote:
| A friend loaned me a fancy usb DAC a while back and I used it
| to listen to music while I worked. After about a day or so I
| asked her if it was my imagination or if the audio really did
| sound better. Her answer was that there's no difference between
| those situations: if I imagine it sounds better, it does sound
| better.
| willis936 wrote:
| I don't have to use my imagination to hear the signals
| coupled into my USB DAC when I move my mouse. They're really
| there and I really don't want them to be.
| archi42 wrote:
| Depends on the USB DAC, and maybe/probably the PC. I don't
| have/hear interference with my current setup. I did have
| the issue with another DAC; IIRC I put an RC filter into
| the USB cable power lines (or did I just add an R into the
| ground line? Do some research if you plan on trying this).
|
| PCs these days often still have an optical toslink, that
| can be used to avoid the issue.
| willis936 wrote:
| I have an ODAC+O2. They're not easy to source for cheap
| these days. My issue is that the power supply filtering
| inductor has a cracked iron core (due to me being
| clumsy). The cheapest solution would be to replace it,
| but it's not super easy to swap out surface mount
| components.
|
| I'll just deal with it by keeping the O2 volume low and
| cranking the volume on a second amp. Long term I'll just
| buy an element or a schiit.
| IshKebab wrote:
| Nonsense. Not everyone is an "audiophile" (in a bad sense) who
| believes in silver speaker cables.
| ptk wrote:
| I genuinely wasn't sure whether psychoacoustician was a cheeky
| synonym for audiophile or not. :). I looked it up and, sure
| enough, psychoacoustics is a legitimate field of study.
| amelius wrote:
| How does this compare to just buying a good headphone?
| jensgk wrote:
| Headphones should also be calibrated by doing EQ. See
| https://www.reddit.com/r/oratory1990/wiki/index/list_of_pres...
| timc3 wrote:
| Headphones are excellent, but I find I have a different
| experience with headphones compared to music coming out of
| speakers. Sometimes I prefer one over the other.
| analog31 wrote:
| A good headphone can probably still outperform a speaker
| system. The tradeoff is that you have to wear a headphone. In
| my case, I just hate them. It's just more pleasant for me to
| listen from speakers, despite the fidelity tradeoff.
| vladvasiliu wrote:
| There's also the fact that when you really get "into" the
| music and start moving your head, there are basically two
| scenarios: you either get the "hum" of the headphones moving
| on your ears, or the headphones stay put but the clamp is so
| tight that you can't stand them for more than 10 minutes.
| scns wrote:
| Try good half-open cans like Beyedynamic DT880. I can wear
| them all day.
| archi42 wrote:
| I never really liked wearing headphones as well. I've setup
| my room such that I can use the big stereo speakers plus a
| decent mic (Samson Go Mic) for voice chats.
|
| However, Sennheiser HD650 are a pleasure to wear. Even for
| longer periods of time. I use them with a bluetooth+USB
| DAC/amp (Fiio Q5; outdated) and a short cable; so I'm pretty
| flexible how I can use them.
| zihotki wrote:
| I wonder what are the differences between this tool and industry
| standard REW app - https://www.roomeqwizard.com/
| amluto wrote:
| Source code, for one.
| TacticalCoder wrote:
| Isn't it basically what "DRC" does? (Digital Room Correction)
|
| https://en.wikipedia.org/wiki/Digital_room_correction
|
| I don't remember the exact order but way, way, way before the $10
| K USD digital audio cable snake oil, audiophiles are going to say
| that DRC is the second single biggest thing that can enhance the
| quality of your setup (the first one being which speakers you're
| using and how you place them). Then source quality/amp/dac. And
| only way further down the line, for those who believe in voodoo,
| $10 K digital audio cables.
| timc3 wrote:
| Seems to be some kind of DRC.
|
| $10K digital audio cables are never a good idea.
|
| I remember I went to some audiophiles house once to demo some
| speakers, and his "hobby" seemed to have taken over the house
| and common sense. He had crazy expensive audio equipment and
| some of the thickest cables I have seen, with the cables all
| suspended on little bridges.
|
| All this in a room which was basically a square brick
| construction with glass windows on 3 sides, no thought to any
| treatment. He didn't seem to understand that the room was
| effecting the sound more than any DAC, Amp, Cable, or any of
| the other voodoo that was going on. I couldn't properly demo
| the speakers because of a particular standing wave. I concluded
| he probably had a hearing problem, he concluded he needed to
| upgrade a cable.
| simondotau wrote:
| An objectivist audiophile would say that room correction is
| among the three or four _grossly consequential_ parts of the
| audio chain. They are, in serial order:
|
| 0. Source material
|
| 1. Room correction DSP
|
| 2. Speakers (including subwoofers and crossover configuration)
|
| 3. Room acoustics (including positioning of speakers and
| listeners)
|
| 4. The human (ears, experience, expectations, ego, etc.)
|
| All of the above are more consequential than anything else,
| assuming the core components are not total garbage,
| underspecified or malfunctioning. This includes the DAC and
| amplification.
|
| Of the above list, I would place room correction at the bottom.
| It is the cherry on top of a great system, not the means to
| achieving greatness. And it lets you get away with some things
| (most notably, mismatched speakers) to a greater extent than
| otherwise. But despite the name it can't fix real acoustic
| problems.
| IAmGraydon wrote:
| I'm not an audiophile in the obsessive-compulsive sense, but I've
| been recording music in my home studio for 20 years and I know my
| way around it. This sort of calibration is not ideal. Not only
| are you measuring with a device that has an imperfect response
| curve, but you are also measuring the room at a single monophonic
| point in space. The way that sound interacts with the room and
| your ears is far more complex than that. Ultimately, this is a
| bandaid for a poorly treated room. If you're serious about
| getting a flat response curve from your monitoring room, you're
| far better off learning how to treat the room properly and how to
| position your monitors within the room for the best results.
| vladvasiliu wrote:
| > you're far better off learning how to treat the room properly
|
| Would you have some pointers on this?
|
| I've been looking into this and while I've found pointers on
| "what to do", what's missing is where to actually find the
| necessary panels and how to figure if they're actually worth
| anything.
| zoltar wrote:
| Here's some basic before/after examples that might be useful.
| This is kind of a deep rabbit hole. My dumb brain still
| dreams of blackbird studio c every once and a while.
|
| https://www.youtube.com/watch?v=dB8H0HFMylo#t=6m22s
| colanderman wrote:
| I've found https://ehomerecordingstudio.com/acoustic-
| treatment/ to be a well-written and informative guide.
| its_bbq wrote:
| Build your own panels with rockwool insulation. There way
| better than almost anything you'll find on the market and
| easy even for no talent carpenters like myself
| vladvasiliu wrote:
| How do you cover those? I'd expect drywall or similar would
| negate most benefits.
| timc3 wrote:
| Fabric that you can breath through easily for looks.
| Under than you can be very thin fabric that makes sure
| that the fibres from the insulation doesn't escape.
|
| I use this for looks: https://www.camirafabrics.com/en/co
| ntract/inspiration/acoust...
| timc3 wrote:
| Exactly. If you really want to get into it the depth of the
| construction of the panels you need is based on some maths
| - density of the insulation material and it's particular
| properties but all of that can be found out on forums such
| as this one: https://gearspace.com/board/studio-building-
| acoustics/ - vs the frequencies you wish to treat.
|
| You can put your room dimensions into a calculator and get
| a rough idea of some of the try and find the modes of the
| room - which you want to treat, though sometimes it takes
| trial and error as well. But you want to treat the point of
| first reflection and then have bass trapping in the
| corners.
|
| Don't buy that "acoustic foam" that looks like egg cartons,
| it's rubbish.
| ibigb wrote:
| You might look here: http://realtraps.com
|
| You can probably reduce some room resonances.
| drcongo wrote:
| You'd also be relying very heavily on the microphone used to
| measure it.
| OJFord wrote:
| That's the 'device with an imperfect response curve', I
| assume.
|
| In fairness, the readme does state:
|
| > A good microphone is needed, with a wide frequency range
| and preferably with a flat frequency response.
|
| By 'preferably' I assume it's implied that it can curve-fit
| (whatever's needed, I know next to nothing about this) to a
| non-flat microphone response, as long as it's known, but if
| it's flat then no need.
|
| If it's unknown (and non-flat or assumed non-flat because
| it's cheap and doesn't make any claims about it) then that's
| the real problem, no point trying to do anything because it's
| like trying to construct a level floor with a shoelace for a
| spirit level.
| rodgerd wrote:
| Commercial systems that do this kind of room correction
| generally have a limited range of recommended microphones,
| and the more expensive (and hopefully better) ones will
| have the microphone calibrated and factored into the room
| correction - for example, Anthem's Room Correction (ARC)
| ships mics that have a serial number. You plug that into
| the ARC software, it looks up the factory profile of that
| specific mic, as it was recorded at build time, and weights
| the calibration for it.
| retcore wrote:
| Here's a measurement standard mic:
|
| https://earthworksaudio.com/measurement-microphones/m23/
| leeoniya wrote:
| i always wondered, is it possible to take a cheaper mic or
| iems and "flatten" them via an eq, to perform nearly as
| well as professional gear that's 3x the price?
|
| i just picked up a pair of KZ AS06 iems [1] and my
| listening preference is U shaped (which is how these are
| dialed in out of the box), but i imagine with quality
| hardware and e.g. 3+ dedicated, drivers it should be
| possible to flatten them out in an eq.
|
| [1] https://old.reddit.com/r/headphones/comments/eqpsen/kz_
| as06_...
| mastax wrote:
| Yes, to an extent, and this is frequently done to great
| effect. However frequency response isn't everything,
| there's also e.g. group delay, off axis response, and
| harmonic distortion. In particular, boosting response in
| areas a speaker is deficient often causes a huge increase
| in distortion, so you have to balance.
| LeSaucy wrote:
| How does this compare to dirac?
| tpict wrote:
| I'm finding the "this is a horrible idea" responses amusing. I
| don't know if there's something fundamentally different about
| the way this project works versus Dirac/XT32 or if the
| naysayers aren't familiar with it. Or maybe there's an anti-
| room correction sect of audiophiles that have remained hidden
| to me.
| stinos wrote:
| Not 'fundamentally', but using one single point would
| probably be the main issue. Move the microphone 5cm and the
| response measured is going to be different. Dirac and manual
| methods with REW use multiple points and/or just moving the
| microphone around.
| chamod12 wrote:
| tomduncalf wrote:
| Cool project! I recently bought a set of iLoud MTM monitor
| speakers which come with a special mic which they use to analyse
| the room and correct for it in a similar way to this.
|
| It makes a good difference to the sound - highly recommend the
| speakers if you are looking for a smallish set of monitor
| speakers that sound great and can be used very near field so you
| can use lower volumes.
| timc3 wrote:
| Yeah, those are kinda cool. They have the added advantage that
| they don't have a huge amount of bass, though what they do have
| is impressive for their size to be fair.
|
| But because of their size they don't always activate room
| acoustics in a crazy way, and a lot of people monitor with them
| fairly close so don't need them loud either further lessening
| the problems.
| archi42 wrote:
| > a lot of people monitor with them fairly close so don't
| need them loud either further lessening the problems.
|
| This simple insight is gold. But is it actually true? The
| standing wave should still pop up. Though with less energy
| it's probably mostly handled by the furniture.
|
| Whatever the case, having monitor speakers sitting close
| avoids/lessens the issue of the first reflection point,
| making the higher bands sound much less "muddy". This can be
| improved by picking a speaker with a strong beaming
| characteristic. Eg 4" broadbands will bundle the acoustic
| wave quite strongly in the higher frequencies. Sounds muffled
| for bystanders outside the beam, but amazing stage and
| resolution for the one or two persons inside of it.
| anotheryou wrote:
| I'm using the commercial https://www.sonarworks.com/soundid-
| reference and it's amazing.
|
| I'd say the worse your setup (especially your room) the more
| magic it does.
|
| I did it without an individually calibrated mic though (but with
| a decent measuring one), wonder how much better it could be.
| RedShift1 wrote:
| Is it affordable for mortals or is this a business only
| offering?
| anotheryou wrote:
| Certainly expensive. ~300 eur/usd with mic (and you need a
| proper audio interface to support the mic).
|
| A bit sad, because it might do most for less expensive
| speakers and untreated rooms.
| timc3 wrote:
| It's cheap compared to a Trinnov system. But honestly you
| might be better off spending 300eur/usd on wood, Rockwool
| and some fabric.
| brandonmenc wrote:
| I'm also using this.
|
| The results are very good. I have studio monitors and a crappy
| room setup, and the calibrated sound is much better. I
| purchased the kit with the supplied mic.
|
| That said, the software is unstable. To the point of
| uselessness. It caused so many system crashes that I - very
| sadly, because the results are so good - just don't use it
| anymore.
|
| Hoping they fix stability in later versions so I can go back to
| using it.
| anotheryou wrote:
| I think a lot happened shortly before the rebranding to "
| _SoundID_ Reference ". If you tested before that, maybe give
| it another go.
| brandonmenc wrote:
| I stopped using it about a week ago.
| rcarmo wrote:
| This is very nice. I also appreciate the pointers to various
| equalizer apps in the README, I didn't know a couple of them.
| dfbb wrote:
| qbonnard wrote:
| Newbie question: how do we know we can trust the microphone?
|
| It sounds like a chicken-and-egg problem to equalize speakers
| with an equalized microphone, but maybe microphones are simpler
| and can be assumed to be equalized ?
| pier25 wrote:
| There are cheap calibrated mics available. There's one for
| about $20 from Dayton Audio.
| AndrewUnmuted wrote:
| tibbon wrote:
| You'll need a calibration curve for the microphone. Even of the
| same model, there is a lot of variance.
| willis936 wrote:
| Anyone interested in this area should also know that above ~2
| kHz it doesn't matter what you do for magnitude equalization
| because you'll be dominated by sub mm variations in position
| and direction. The only way to get any amount of
| repeatability above 2 kHz is with IEMs.
| erdewit wrote:
| This is dealt with by smoothing the spectrum in a way to
| preserves the power density. The constructive and
| destructive interference then cancel each other out.
| Gracana wrote:
| What does "smoothing the spectrum" mean? What operations
| are being performed?
| danuker wrote:
| I'd guess: Fourier transform, a power density preserving
| blur convolution, then inverse Fourier transform.
|
| But I am not familiar with the field of signal
| processing.
| doctorhandshake wrote:
| There's an example of doing this on the readme- scroll way
| down
| gh02t wrote:
| MiniDSP makes some calibration mics that run about 60 bucks.
| I used them as a cheap instrument for some lab work where I
| needed a calibrated mic a while back and was very impressed
| with their performance for the price. They ship with a little
| code that you can use to retrieve the calibration curve from
| the factory, and I know a lot of people use them for hifi
| calibration with REW.
| O__________O wrote:
| Not an audiophile, but one way might be tuning forks. That
| said, I would be super surprised if this was needed for high-
| end microphones.
| amluto wrote:
| A microphone's ability to reliably identify a frequency is
| excellent, even if the microphone is cheap, crappy and
| uncalibrated. It's almost entirely a function of whatever
| clock is used to digitize it, and oscillator chips that are
| just fine are ubiquitous.
|
| The issue is calibrating the _amplitude_ response at a given
| frequency, and a tuning fork won't help.
|
| edit: those quartz oscillator chips have a lot in common with
| tuning forks.
| Schroedingersat wrote:
| A microphone that is linear to a dB or so is far cheaper than a
| speaker that is linear to 6dB and room treatment that maintains
| that.
| hedgehog wrote:
| This looks cool. I'm not sure if they are intending to go all the
| way to room correction but it can really do wonders. A good while
| back my music setup used filters calculated by an open source FIR
| tool with playback driven by an older version of Shairport
| (emulating an AirPort express) using BruteFIR as a convolver.
| Fiddly to set up but it sounded really good.
|
| 1. http://drc-fir.sourceforge.net
|
| 2. https://github.com/mikebrady/shairport-sync
|
| 3. https://torger.se/anders/brutefir.html
| strainer wrote:
| I have made a small webtool to help calibrate various EQs by ear.
| It kind-of mimics a graphic EQ in the browser which can also play
| tones around the EQs frequency bands, which should sound about
| the same loudness as their neighbors according to the ISO
| loudness curve. I increase or decrease my laptops EQ bands until
| the tones on the webtool play without obvious difference. This is
| sure to be an unsatisfactory process for technical purposes, and
| I couldn't even guarantee that I implemented the loudness curve
| well, but I have a lot more success using it to help tune EQ than
| without it.
|
| https://strainer.github.io/hearqualizer/
| etaioinshrdlu wrote:
| I think it would be cool to make a more advanced version that
| corrects for many types of nonlinearities: amplifier distortion
| and mechanical parts resonating badly.
| lvl102 wrote:
| I highly suggest getting flat neutral speakers first. Preferably
| high end studio monitors. What would be interesting is if someone
| can work on music-specific optimization based on a handful of
| inferences and ML.
| timc3 wrote:
| Nope, it's better to treat the room first, then invest in some
| quality monitors like Neumanns. Basic budget monitors will do
| great in treated room.
| runeks wrote:
| I've tried this for my speaker setup. And the problem is that the
| frequency response is a function of volume. For example, the
| louder I play music the more the bass is accentuated. I think
| this is because of standing waves.
|
| So the problem I find is that when the volume is low the bass is
| too low, and when the volume is high the bass is too loud. Only
| when I play at the same volume as the equalization was performed
| at do I get a good result.
| fhchl wrote:
| This is a common psycoacoustic effect and probably not due to
| the loudspeakers or the room acoustics (which are linear): the
| (perceived) loudness of a tone is frequency and level dependent
| [1]. This makes sounds more bassy at large sound pressure
| levels.
|
| [1]: https://en.wikipedia.org/wiki/Equal-loudness_contour
| newaccount74 wrote:
| Some hifi systems have a "loudness" setting that raises
| bass+treble to compensate for this effect at low volume.
| timc3 wrote:
| This type of software, is just a bandaid and really doesn't work
| very well (though it can work better with headphones). Properly
| thought out and tuned acoustic work is what is needed.
|
| I am lucky enough to have a spare room in my house, and set out
| to build a studio (an almost life-long dream) and decided that I
| didn't want to compromise on the acoustics and spent some time
| looking into the subject. In the end I built it myself with a
| huge amount of acoustic treatment (lost a large amount of the
| volume room), but more that that I enlisted the help of a
| professional who could do the maths and help with not just the
| trapping but also the panels that are needed. In the end after I
| built it was also tuned with DSP by the professional, has what
| you would normally call 4-way speakers with the subwoofers going
| to a higher frequency than most would consider normal and even
| the desk was specifically chosen to not cause a problem for the
| listening environment. The difference between this and something
| like Sonarworks (commercial software that I tried for a laugh
| beforehand) cannot be overstated. It's basically flat between
| 23hz (slightly rises at 20hz I believe) and 20Khz - we actually
| tuned in a more natural response curve.
|
| It's still a home studio because it's in my home and I don't do
| anything commercial with it, but it's pretty much mastering
| grade, all with materials that are available in a builders yard
| and the special sauce, someone that knew what they are doing. Not
| everyone has the room or space to do this, but most people can
| build some bass traps and something to tame first point
| reflections.
| danuker wrote:
| This project still has a good bang for the time or money buck.
|
| Life has compromises. You do give up some things to build a
| perfect studio.
| solardev wrote:
| Asking because I'm not smart enough: Is this kinda similar to
| what the Sonos Trueplay feature does? (Where you move your phone,
| and/or a mic-enabled speaker itself, around the room so that it
| plays and measures various frequencies to calibrate)
|
| https://support.sonos.com/s/article/3251?language=en_US
|
| https://patents.google.com/patent/EP3531714A2/
| zihotki wrote:
| That one is an automatic room equalization, it's different from
| speaker equalization and it probably should be done after
| speaker equalization. But it's more useful for the end user.
| solardev wrote:
| Sorry, I might've linked the wrong patent then. (I meant to,
| but failed to, find the one that handles speaker equalization
| for a single speaker).
|
| By room equalization, do you mean normalizing volumes between
| different rooms, or...?
| newaccount74 wrote:
| Room equalisation is about counteracting the effect of the
| room and the placement of the speakers. For example, when a
| speaker is close to the wall, or in a corner, low
| frequencies are amplified, even if the speaker on its own
| has a flat response cureve, so you would reduce low
| frequencies to adjust for the room.
| patrakov wrote:
| There is an older project with better math inside: http://drc-
| fir.sourceforge.net/
|
| For starters, it doesn't try to achieve a phase-neutral response,
| because a phase-neutral response created in a room is only valid
| in one point of the room, and creates pre-echo artifacts
| elsewhere. In fact, it tries to separate the response of the
| speaker itself from the response of the room, by setting a
| threshold in the time domain, so that everything coming before it
| must be unaffected by the room. Then, everything coming before
| the threshold is corrected to a linear phase, while everything
| else is corrected to the minimum phase (thus making the second
| part of the filter purely causal).
|
| Also, they provide an argument, citing literature, that
| equalizing to a flat frequency response would be wrong in a room,
| and thus provide an option to remove excessive treble and achieve
| a 1dB/octave roll-off.
|
| Please see the details at http://drc-
| fir.sourceforge.net/doc/drc.html
| erdewit wrote:
| > because a phase-neutral response created in a room is only
| valid in one point of the room
|
| Author here. The term "phase-neutral" simply means here that
| the impulse response is symmetrical and doesn't add a phase
| shift. It doesn't even try to neutralize the phase
| characteristics of the room, which is what you may be thinking.
| In fact the phase information from the measurement is
| completely discarded. Furthermore, the frequency response is
| averaged to get a more general and robust (less over-fitted)
| correction that works pretty well across the room. Try it...
| patrakov wrote:
| Well, if you discard the phase of the original response
| anyway, then you can shave a few milliseconds of latency by
| switching to minimum-phase (which is causal, not symmetric)
| instead of linear-phase. The math is in
| scipy.signal.minimum_phase.
| [deleted]
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