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

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

#51

Post by miah_ »

This is a neat idea. I don't know why it needs to be an app on a phone though. I guess you "know" a phone has a microphone and the setup is minimal and you have a api for everything? It being a phone app leads me to believe the 'no data collected' bit is temporary as all phone apps eventually gobble data to sell.

I have an Android so I can't try this out, as its in 'private beta' on Android currently.

Would love to see this as a open source project that I can install on Windows or Linux though.

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

#53

Post by fwip »

derefr wrote: post #47
crazygringo wrote: post #26

This seems really clever -- kudos! I'm curious how it actually works? At first I assumed you were comparing the vinyl track to the reference digital track from some streaming service and either analyzing the frequencies with FFT or the timing of peaks. But I watched your demo video and you don't need to tell it anything about the song. Which makes me think you're rather doing an FFT and simply trying to match how wel…

You can extract pitch information and compare it to a set of quantized reference pitches as an instrument tuning app does, sure. But you can also extract BPM info and compare that to a set of quantized reference BPMs that anyone would ever bother to use. And also, since you’re getting multiple pitches from multiple instruments in a time series, if you can isolate particular instruments, you can calculate the key the…

Are there really "standard" BPM? As far as I know, most music production is just "whatever tempo the band feels like playing." I haven't been in a recording studio, though, so maybe a use of a metronome is more common there?

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

#54

Post by svantana »

hobofan wrote: post #50
shudza wrote: post #45

I've used to use an app (there are many) which measures angular velocity using accelerometer and displays RPM (you place the phone on the turntable). I can't see why would anyone need something other than that.

Complete noob here, but wouldn't the phones weight (especially with how big phones are nowadays) have a significant impact on the RPM by slowing it down?

It's very possible, increased weight will increase friction in the bearing. However my iphone SE weighs almost the same as a 12-inch record (150g). BUT it is also more difficult to place symmetrically on the turntable, which also could affect friction.

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

#55

Post by kazinator »

nickthegreek wrote: post #25

Just put a record on yesterday and my wife said it was playing too fast. I thought she was wrong, then I see this post today! I grabbed the app and gave it a go, 3.5% too fast according to your app. Now I have to figure out how to adjust the damn thing. Really appreciate a free nonsense free app. update: youtube to the rescue. pretty common affordable turntable( Audio-Technica LP60), so I figure I would put the vid l…

3.5% is a lot! One semitone is a bit shy of 6 percent.s

It's between 59 and 60 cents: more than a quarter semitone.

Exact value:

  1> (* 1200 (log2 1.035))
  59.5569212695205
So 59.6 to 3 sig figs. Someone with a good pitch memory of a tune (hearing in their head how it should sound) would spot such a difference. Especially if they heard the tune recently.

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

#56

Post by sambeau »

svantana wrote: post #46
sambeau wrote: post #33

Earlier quoted context omitted.

My first thought was that it is listening to the scratches rather than the music, but I guess they speed up as the record gets played and the arm moves inwards. So, my second guess is that it's listening to the pitch of the notes being played. Of course, old albums (especially punk albums) are probably tuned to whatever worked on the day—maybe a tuning fork, possibly a piano, maybe just to one of the instruments.

Umm, no, scratches meet the needle once per revolution, regardless of the needle's position. So that would definitely be a possible method. But not all records have scratches, or they could be at an angle, which would give the wrong estimate. Also, actual sounds on the record could have scratch-like qualities.

>scratches meet the needle once per revolution, regardless of the needle's position

I need to go away and think about that :D

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

#57

Post by FelipeCortez »

nickthegreek wrote: post #25

Just put a record on yesterday and my wife said it was playing too fast. I thought she was wrong, then I see this post today! I grabbed the app and gave it a go, 3.5% too fast according to your app. Now I have to figure out how to adjust the damn thing. Really appreciate a free nonsense free app. update: youtube to the rescue. pretty common affordable turntable( Audio-Technica LP60), so I figure I would put the vid l…

hey, I have the same one and didn't know about these controls! I'll definitely try this out now

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

#58

Post by gamegod »

peter_l_downs wrote: post #49

Strongly recommend updating your website to lead with some variation of "This is an offline iPhone app to help you calibrate your turntable's speed, all you need to do is play your records and the app will show you the current RPM" — wayyyyyyy too many words and other nonsense before I could figure out this is what it did. Embed the demo video (the tweet you linked) too! Looks great and if I still used records I woul…

Yeah, but he gets great time-on-site engagement numbers by doing that. Somebody give this guy a job in Silicon Valley!

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

#59

Post by berkes »

peter_l_downs wrote: post #49

Strongly recommend updating your website to lead with some variation of "This is an offline iPhone app to help you calibrate your turntable's speed, all you need to do is play your records and the app will show you the current RPM" — wayyyyyyy too many words and other nonsense before I could figure out this is what it did. Embed the demo video (the tweet you linked) too! Looks great and if I still used records I woul…

Maybe they already changed it, but there's a chapter "As easy as 1-2-3."

I'd personally move that way up. I had to scroll across all sorts of fluff and effects. I was sold by this (edit: this chapter, not the fluff)

Maybe I'd personally even research how to make the entire website just that. Where maybe step 0 is "install the app" :D

The (promised) simplicity of the app doesn't show in the communication of the website at least.

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