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Show HN: I made a free app to calibrate your turntable by simply playing a song

grooved.okat.best

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Show HN: I made a free app to calibrate your turntable by simply playing a song

#1

Post by okatbest »

Hey there!

I made a little app that lets you to calibrate your turntable by putting on any record and tapping a button. It's called Grooved and it uses your phone's microphone to see how fast your platter is going, almost like magic.

You can see what it looks like in action here: https://twitter.com/OKatBest/status/1795453042994680148

The app itself is free without ads, subscriptions, or trackers. It's a tool I built for myself, and I just thought someone else might want to use it too. I have never seen this technology being used before, all other apps require you to either print something and use the camera, or to place your phone on the spinning platter and use the accelerometer.

You can grab it on the App Store, and I am working on an Android version I hope to release at some point in June.

Would love to hear what you think about it!

Ivan_

Show HN: I made a free app to calibrate your turntable by simply playing a song
grooved.okat.best

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#4

Post by echelon »

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates?

How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#5

Post by patrakov »

Does it rely on the fact that music has a concept of notes with well-defined frequencies and that there is no such thing as 216 Hz (must be 207.6 or 220 Hz) when the music is played on a properly tuned instrument? Or does it use other heuristics?

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#6

Post by CaptainOfCoit »

echelon wrote: post #4

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

> I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates?

Lots of turntables have variable speed, DJs can tell you more about it :)

> How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

When you're DJing, one of the main things you'd deal with, is making things be in sync, one way or another. I'm not sure how much value you'd get from an app like this that seems to be more "fire and forget" and not for on-the-fly matching.

I'm guessing this app is for people who do their own maintenance, repairs and such of turntables, so they can easily verify their work.

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#7

Post by franky47 »

patrakov wrote: post #5

Does it rely on the fact that music has a concept of notes with well-defined frequencies and that there is no such thing as 216 Hz (must be 207.6 or 220 Hz) when the music is played on a properly tuned instrument? Or does it use other heuristics?

A "properly tuned instrument" still requires a base frequency (usually defined for A4). Whether to use 440Hz or another slightly different frequency is a fun debate to get into.

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#8

Post by beAbU »

echelon wrote: post #4

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

Fancy record players have a trim setting where you can fine adjust the speed up or down a semitone. But all of them have a built in stroboscope/calibrator to help get the speed right. I think the drag of the needle impacts the speed, hence the desire to tune it per record.

Audioplebs need not apply.

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#9

Post by yial »

echelon wrote: post #4

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

So really short description, you have 33, 45, and 78 rpm.

Most record players are belt drive. Anything that is belt drive usually has some slip / variation (if more familiar to you, imagine the belt drive on a lawn tractor). Many have a finer adjustment to tune the spin rate. +- off of the selected rate. (Perhaps you selected 33 rpm but it’s really spinning at 32)

I’m sure someone who knows much more then I do, could give a much better explanation along with other types of tuning. (Arm weights, needles, etc etc)

Re: Show HN: I made a free app to calibrate your turntable by simply playing a song

#10

Post by datpiff »

echelon wrote: post #4

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

Models targeted at DJs will have variable speed adjustment on the front panel to allow beat-matching. Some turntables for home listening will have 2 or 3 speeds with a fine adjustment for calibration.

Rates will be off due to manufacturing tolerance or mechanical wear (i.e. a loose belt slipping on a motor).

Most people don't worry about it.

It doesn't really vary album-to-album, unless you have some ridiculously heavy records that slow the motor.

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