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Does anyone us RPM app on their phone for TT speed adjustment?

L

lightcapture

Super Member
My turntable has electronic speed adjustment but no strobe. I tried RPM app on my phone and find it changes rpm depending where its placed on the platter. Is there a best location or are these apps not accurate enough for TT adjustments?
 
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I'd use a strobe disc from VE to check speed as I wouldn't trust an app to be "dead on balls accurate, it's a technical term".
 
Blue Shadow said:
I'd use a strobe disc from VE to check speed as I wouldn't trust an app to be "dead on balls accurate, it's a technical term".
Click to expand...
+1

The line frequency of your home is usually very accurate and I would trust it over an app that may be affected by processor speed or load in trying to calculate your platter speed.
 
I've started using the 'rpm speed' app and it's a lot more informative than just a strobe disc. In comparison a strobe disc is guessing since all you see are blurry spots wobbling.

You can see Rom speed and wow and flutter (unweighted). With the app I get a clear graph that tells me a lot more (just like an ecg heartmonitor). You can tell if there's a periodicity or just random fluctuations, so if it's the belt, pulley or subplatter. I can even tell the difference in platter weight.
 
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I agree that the RPM Speed app is more informative and I think it can be good enough. I place my phone on the center on the platter after putting an upside down cup or just a roll of tape around the spindle.

The accelerometer in the phone is likely not dead center so you could play around with exact placement to see what gives the most consistency.
 
It's a little expensive but....the Phoenix speed controller is about the best solution.
 
JD#7 said:
Out of business I thought ?
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Yes, a couple of years ago. Owners rarely let go of them, so they are hard to find now.

Music Hall has a similar product. However, it does *not* work with all TTs.
 
techguy0192 said:
so they are hard to find now.
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Not a widely known fact but Sota bought the rights to Phoenix eng some time ago and is selling them
with their tables as an option and adapted them to be used on the competitions VIP tables
a very wise move on their part.
 
]eep said:
I've started using the 'rpm speed' app and it's a lot more informative than just a strobe disc. In comparison a strobe disc is guessing since all you see are blurry spots wobbling.
You can see Rom speed and wow and flutter (unweighted). With the app I get a clear graph that tells me a lot more (just like an ecg heartmonitor). You can tell if there's a periodicity or just random fluctuations, so if it's the belt, pulley or subplatter. I can even tell the difference in platter weight.
Click to expand...

Montycat said:
I agree that the RPM Speed app is more informative and I think it can be good enough. I place my phone on the center on the platter after putting an upside down cup or just a roll of tape around the spindle.
The accelerometer in the phone is likely not dead center so you could play around with exact placement to see what gives the most consistency.
Click to expand...

I tried placing phone perpendicular to spindle with top of phone touching spindle.
I tried it perpendicular to spindle but at record edge and got different speed.
I'll try it on the center of spindle. Thanks
 
]eep said:
I've started using the 'rpm speed' app and it's a lot more informative than just a strobe disc. In comparison a strobe disc is guessing since all you see are blurry spots wobbling.

You can see Rom speed and wow and flutter (unweighted). With the app I get a clear graph that tells me a lot more (just like an ecg heartmonitor). You can tell if there's a periodicity or just random fluctuations, so if it's the belt, pulley or subplatter. I can even tell the difference in platter weight.
Click to expand...

Your supposed to put your glasses on when using the strobe disc. Just a saying...:rflmao:

Cheers
Mister Pig
 
I used RPM Speed and Wow on Android recently to test my Orbit Walnut and it produced some pretty good numbers. Same as others, I centered the phone as best I could on top of a record weight. Speed was pegged at 33.35 with wow .08 on three successive runs. For a budget machine I was pleased. I think the app is useful.
 
]eep said:
blurry spots wobbling.
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If its wobbling, something is wrong. Fast shifts are flutter, slow shifts are wow. The lighting in use does have something to do with all of it though. LED or more modern (like less than 30 years old) florescent lighting may not be operating at mains frequencies. Strobe discs require that for proper results.
 
gadget73 said:
If its wobbling, something is wrong. Fast shifts are flutter, slow shifts are wow. The lighting in use does have something to do with all of it though. LED or more modern (like less than 30 years old) florescent lighting may not be operating at mains frequencies. Strobe discs require that for proper results.
Click to expand...

(I know you're just trying to help but you don't give me much credit here)

So... you are saying that... you never used the app just a strobe disc?

@mr Pig: im even wearing 2 to read it! :cool:

Just FYI, I have training as chemical analist and a large part of the training is measuring and how to correctly read a dial or hand or digital display and how to correlate the results to find a conclusion. Kind of like CSI. So thank you for clearing up what causes what. ;)

Doesn't it bother you that those blurry blotches are used to resemble anything scientific? Or exact? It's like Keppler observing the moons of Saturn.

The strobe effect of light bulbs are very blurry over time axis because of afterglow of the glowwire. And it's a (distorted) sine, not a block wave. Modern LED's switch on much faster but there's more fluorescense, but still a lot easier to read.
The gyros and clock in modern smartphones are quite precise.

I was trying to find a screenshot... These are from and old Philips 212 with pitch control. I don't need any glasses to adjust this.
Philips 212 meting 2 grafiek.jpg

Philips 212 meting 2 tt en wow.jpg
 
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You don't use a strobe disc with light bulbs! You'll get the blurry mess you describe, though it can be done. You need a neon bulb (or a line powered LED circuit I can show you) so the flashes are at 120 Hz. The bars/dots should be quite sharp and it's trivial to see if the platter is fast or slow. You can also go really low tech and just put a piece of easily visible tape on the platter, then time 100 revs with a stop watch. Or a phone. Then use the calculator in your phone to calculate the RPM. Man, I've gotta get a phone.
 
MRL_Audio said:
Is there something wrong with doing that? I mean old school... is that not a workable solution?
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Sorry, I was still editing. I didn't want to be harsh. I always have to read 3x because I'm from a different culture and language.

But, yes there is something wrong. No there's nothing wrong with using a strobe. But there is something wrong about condemnation before investigation. You can only really objectively compare if you used and tested both, can't you?
 
ConradH said:
You don't use a strobe disc with light bulbs! You'll get the blurry mess you describe, though it can be done. You need a neon bulb (or a line powered LED circuit I can show you) so the flashes are at 120 Hz. The bars/dots should be quite sharp and it's trivial to see if the platter is fast or slow. You can also go really low tech and just put a piece of easily visible tape on the platter, then time 100 revs with a stop watch. Or a phone. Then use the calculator in your phone to calculate the RPM. Man, I've gotta get a phone.
Click to expand...

Then why are all vintage turntables equipped with a strobe supposed to be used with light from a light bulb? (Maybe it's easy to print and it gives the user a false sense of security?)
I have just repaired a Thorens TD-115 and everything is working now, except for... the light bulb in a plastic bubble that is supposed to shine through the sharp strobe holes in the platter to mesmerize the user.

So yes, you're right. But my phone, this one here, is more powerful, has way more memory and can do lots more than my previous desktop pc and is vastly smaller. But it won't last as long.

What I'm saying is: technology is going at a rapid pace. But durability and longevity are not considered important. So use your phone where it's useful but for audio you better stick to the simplest solution.
 
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