Speed test using a stopwatch and known track (timing)

adnick

adnick

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Here’s a fun and interesting test, use an album like Miles Davis “Bitches Brew” with the 27:00 min track of the same name.

Set your stopwatch and hit start/stop as close to the first/last note played, the results should be within 1 second or less if the table is truly running at 33&1/3 rpm. Human error can account for a 1/2 second or so, but if it’s several seconds off then the speed is not constant over time, there’s several possibilities as to why.

The Bitches Brew track is perfect for this test at 27:00 minutes exactly, but any longer track will do….

Have run this exercise on several of my machines, it’s not difficult to do:cool:

Getting ready for a run:

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VR
Andy
 
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What is this exercise trying to show? If I was trying to measure speed accuracy, I’d use an app like RPM.
 
That's a clever and easy to implement idea.

More effort than measuring a tone from a test record, but the stopwatch method is something anyone can do.
 
The stopwatch & revolutions is certainly the most accurate speed test.

However speed accuracy over a long period of time could get tedious, counting revolutions.;)

Speed tests without dropping the tonearm are inaccurate on tables without dynamic speed control.

This type of test was explained to me by an old DJ, he called it timing…accuracy over time is the real test.

For tables without dynamic speed control it can be a revealing test, on occasion it can be revealing on any table :naughty:

Keep in mind that one needs a record with published record times….The suggested track has a published exact music play time of 27:00 minutes


Andy
 
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I don't know if it's the apps themselves that are inaccurate or the hardware in different phones that is inaccurate, but anyone with 2 different phones (that have the required sensors) can do this:


I mean they can't both be right....right?
However they can both be wrong :rolleyes::biggrin:

The differences seem to be the biggest with the actual RPM measurement. With the wow/flutter data, differences are smaller. I don't know if that is because sensors are more in line with eachother there of if it's a result of the calculations being made to come to those numbers.

To me the RPM numbers those apps generate are just an indication and I would never use that to for example fine tune the rpm speed on a quality turntable.
 
Or put a white dot on the platter and let a photocell sensor and a counter do it's job over the night.:D

using the 27:00min track 'only' gives 0,06% resolution, if that number is correct, and that is a value a lot of quality turntables even fall within, especially quartz DD's.
 
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