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variance of +/- 10 Hz with 1 kHz test tone

I tried the Dr. Feickert Speed Tests iPhone app. I don't have his test record for the 3150 Hz track and the app says that you can use a 1000 Hz tone. I have a 1000 Hz tone from the Clearaudio sweep / burn-in record and tried that with the iPhone app running and showing microphone input on the meter. The app registered nothing. Has anyone else been able to get his iPhone app to work with a 1000 Hz tone? Are there any known problems with this app on iOS 7?

I used another iPhone app "Tuner Lite" and it showed my table to average right on for a F# 5 with the tuner set to concert A 440 Hz using the 1000 Hz tone. The Tuner Lite meter did fluctuate between the sharp and flat side (again within the two inner arrows, about +/- 10 Hz and were equidistant on both the flat and sharp side) during even time slices / cycles. Is this wow? Flutter? Good, bad or indifferent? Hole off center on test record? Strobe 33.3 reading looks to be dead on using the same Clearaudio disk with stylus on the record.

Phono setup is:
RP6 with GT ref subplatter and TTPSU
Herbie Mat Way Excellent II-2mm
Audio-Technica AT-33PTG/II 0.3mV MC
Salience / Jasmine LP2.0 mkII

Thanks,

Scott
sbrownnw
sbrownnw OP
710 posts
 
Ok, some new info here. I figured out why the Platter Speed app was not registering. I didn't realize that side 1 of the Clearaudio burn in LP is 45 rpm. Once I set the TTPSU to 45 rmp, the app registered the new data, which follows:

- speed varied between the -.2% slow mark and +.3% fast mark during the 1 kHz test in the first section on the first screen of the app
- unfiltered frequency varied between 1006 (with a few peaks at 1008) and 996 Hz over 35 seconds on the second screen of the app
- filtered frequency was almost completely flat at 1002 Hz over 35 seconds on the second screen of the app

So, if I'm reading this correctly, the filtered looked very good and it looks like my speed is fluctuating between 33.39 and 33.43 every second.

Much better?
sbrownnw OP
710 posts
 
Correction, speed is fluctuating between 33.27 and 33.43.

Here are some more app numbers from the 35 second sampling:

mean freq: 1001.3 Hz

raw freq
max deviation (relative): -2.76% / +.63%
max deviation (absolute): -27.6 Hz / +6.3 Hz

lowpass-filtered freq
max deviation (relative): -.16% / +.04%
max deviation (absolute): -1.6 Hz / +.4 Hz

What is the difference between the raw and lowpass-filtered frequencies? What is the net wow / flutter measurement of my table using this app?

Thanks everyone!
sbrownnw OP
710 posts
 
Second run of over 50 seconds was much better:

mean freq: 1001.4 Hz

raw freq
max deviation (relative): -.75% / +.68%
max deviation (absolute): -7.5 Hz / +6.8 Hz

lowpass-filtered freq
max deviation (relative): -.10% / +.05%
max deviation (absolute): -1.0 Hz / +.5 Hz
atmasphere's avatar
atmasphere
11,960 posts
 
You might see how it performs after its been running for 6 hours.
tonywinsc
583 posts
 
What is puzzling is such one sided numbers. Are you holding your iPhone in your hand when recording maybe? Place your iPhone on a table while recording. The raw is the actual frequency swing as the record rotates which includes eccentricity of the record hole. The program filters out this periodic side to side motion of the record since that is occuring at 0.556Hz. The filtered number is your actual turntable performance. The +0.05% looks good; but the -0.1% is troubling and I am wondering if the platter is really slowing down occasionally by that much.
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