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Comment by IAmGraydon | Hacker News Reader

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.

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Calibrated (my Audyssey is +-1DB 20hz-20khz) mics do exist and calibration files do exist for some mics, plenty good enough considering how terrible the average house/apartment room is.

Your totally right about room treatment and why I don't spend more than the budget end of HiFi, because I know how terrible my room makes everything sound..

Ive measured a few rooms and sets of HiFi and the biggest issue I find is not the general frequency response, but room modes, they peak far more than even the frequency response from a cheap boom box. Without active EQ or a notch filter and extensive room treatment then trying to flatten out the response of a speaker is futile if you ignore the room modes. Add in transient and phase responses and you add additional challenges to getting good audio.

Have you tried Dirac Live? Particularly with a receiver that supports their Bass Control feature? My NAD receiver only supports regular Dirac Live and it's still much, much better than any integrated room correction from Denon/Marantz, Yamaha & Co.

The improvement is so noticeable that I assume it would take a lot of resources to fix the room physically in order to achieve similar results.

I don't want to sound to enthusiastic but I'm pretty certain I'll never buy a receiver that doesn't support Dirac Live.

It does however look great for helping me characterize differences in my 3D printed headphone designs. My old resin-printed design has incredibly good bass, and when I changed things up for FDM printing I lost all that low end. I need to try adjusting my design and quantifying the results, as I love the sound of my resin-printed design but would prefer to move to FDM designs as they are much easier to print and make.

Here's an image comparing my old headphone design with good bass in blue, and the new easier to make design with bad bass in red:

https://twitter.com/TLAlexander/status/1569181219446980608

The 50mm headphone drivers were globally out of stock for a year so it is safe to assume the new drivers are from a different manufacturing batch. But my hope is that the problem lies in my headphone design, and the new and old drivers are roughly the same. I don't know anything about headphone design and seemingly got lucky with the old design, so if I need to adjust my new design that's not a big deal. But if the new drivers aren't performing like the old ones, I may not be able to fix things. So next step will be to swap drivers from the old and new headphones and see if the problem follows the drivers or the headphone design.

Images of the old design as well as the link to the onshape files on this git repo:

https://github.com/tlalexander/reboot-headphones

Measurements (particularly, FR and distortion) aren't there or are hard to find.

It'd be most interesting to see them.

Yes I always wanted to do them. For the original set I just compared them to my friend's expensive headphones. It was only today that I did any kind of frequency response testing. But since I don't have a calibrated microphone, it is more useful for doing relative comparison between my headphone designs than it is for providing absolute numbers.

What I wanted to do was build a little headphone test dummy head. But for my relative tests I just shoved my podcast mic, Audio Technica AT2005USB up to the center of the driver on one side of the headphone. Do look at my linked tweet for those FR curves.

However this little adventure has encouraged me to consider building the little head dummy. I have some nice little capsule mics I was playing with that would work nicely, and I have a datasheet for those that probably includes a curve.

This hobby work of mine goes slowly, but I appreciate your suggestion. I will try to tune up my FDM 50mm headphone design so that it sounds at least as good as my original resin printed design, and then look at building a better characterization rig.

> 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.

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

How do you cover those? I'd expect drywall or similar would negate most benefits.

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/contract/inspiration/acoust...

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.

You might look here: http://realtraps.com

You can probably reduce some room resonances.

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

I've found https://ehomerecordingstudio.com/acoustic-treatment/ to be a well-written and informative guide.

Counter-point: The use case is making relatively-shitty speakers in front of the computer better, and single point in space isn't really that much worse than trying to somehow put speaker in place your ears are and accomodate for all 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.

Well, doh, but it costs zero dollars and very little effort.

You'd also be relying very heavily on the microphone used to measure it.

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.

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_...

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.

Yes, but no, but yes.

AutoEq (https://github.com/jaakkopasanen/AutoEq/) does something like this so... yes?

But targets various HRTF curves which aren't neutral or flat, and they usually aim for a Harman target of sorts, so no...

But there are some neutral-sounding curves that seek to just emulate pinna gain, so they have a ~3KHz peak which is required to 'emulate' the natural resonance of your ear, which you don't get naturally when you jam a driver all the way into it.

There's no AutoEq preset for the AS06s. Here's a representative sample targeting the 2019 Harman in-ear target for the KZ AS10s for funsies though: https://github.com/jaakkopasanen/AutoEq/tree/master/results/...

the AS10 and AS06 curves look quite similar, so might work, thanks!

https://www.reddit.com/r/headphones/comments/afsro3/review_o...

Here's a measurement standard mic:

https://earthworksaudio.com/measurement-microphones/m23/

And what would be the "80% of performance for 20% of the price" equivalent of it ?

Minidsp umik-1.

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.

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