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I'm working on the problem and it's not that. I actually got a tablet of the same model off ebay and am able to reproduce the problem on that. The strobe rings are still giving the accurate pitch, but the needle and numbers are doing weird stuff. Hoping to get to the bottom of a diagnosis today.

That's fascinating!

For what it is worth, I don't think my old tablet previously had this problem. I used it plenty of times and there was not the discrepancy between pointer and strobe rings. And the tablet agreed with PianoMeter (EPT) running simultaneously on my Android smartphone. The discrepancy therefore is new, since the update to PianoMeter.

Yesterday there were oddities on the display. The red line indicating the note crawled slightly to the side and was located between the keys:

Yes, this problem is new. It's actually directly related to the faster needle response. I still haven't figured out why it only seems to affect older tablets running older versions of Android, but I've found the problem and will be pushing out a fix soon.

The problem with the red line scaling is new as well, and the fix for that will be out this weekend. That problem appeared because when we switched from raster graphics to vector (for smaller size) the image for the piano keyboard was slightly different in size, but the code for placing the red line wasn't updated and still matched the old keyboard graphic.

Quarter tone tuning = Easy Sitar Tuner

Ian

TBQH, you shouldn't do that. Your app is really great and is extremely helpful. But once you start adapting the app to older hardware and software, you'll lose yourself in pushing out one fix after the other for specific niche problems.

I'd strongly suggest that you define a reference platform and name it as such and shrug your shoulders once you come across user who have a different set up. You'll never catch up.

Shameless plug: I am using Eas^WPianoMeter on a One Plus 5 which actually has really great microphones without any Automatic Gain Control and it runs on an up-to-date Android Oreo. This is what this beautiful smartphone produces in terms of piano audio recording quality, completely without any post-processing:

https://www.youtube.com/watch?v=-9htzzbAHKE

Anthony said that he has found the problem and has a fix. Your suggestion for him to forgo that fix is very inappropriate. Also I suggest you use Google and find the posts about sound problems with the One plus 5 phone. The omission of AGC might not be the most important issue to consider. I am quite biased because I use a $1200 condenser microphone pair to record piano.

Ian

You have a good point here. This particular fix was about fixing something that was broken by an update for a device that was already supported, but in general you're right. According to the statistics that are provided to developers by Google, 0.9% of the people using my app are using versions of Android between 4.0 and Android 4.3 ("Ice cream sandwich" and "Jellybean"). Maintaining compatibility for those older devices at some point is going to limit the functionality I'm able to provide on newer devices, and at some point soon there will be a final update for the 0.01% of users on Android 4.0 (yes, it actually is 0.01%), with newer updates only going to newer devices.

Whoah, Please read what I wrote. I suggested a general approach to fixes by introducing a standard platform, which also means that on needs to draw a line and Andrew himself pointed out that 0,01% of users cannot possibly be relevant for a useful development of the software. And I won't Google for any sound problems that someone might have had with a OP5. Instead you should listen to the link I provided which is proof for the fact that the OP5 makes excellent recordings soundwise.

For what it's worth, I also record my Steinway B with a matched pair of condensers, have both omni and cardioid capsules for them and have 24/96 as the standard format on the Tascam. Which also means that I am obviously less biased than you and more interested in actual results. So, please don't insinuate inappropriateness to a very sensible approach in limiting suport for the software on outdated niche devices. Thank you very much.

It is interesting to follow the development of this application. I tried on two octaves a trial version. In my opinion, very good.

We're loving it!

Remember that when you go to a website that provides a 440 Hz tone, the website is not the source of the accuracy. It is whatever computer or device you are using to visit that website. All the website does is provide instructions for the browser to "play this waveform at 440 Hz". The HTTP protocol which handles all browser traffic is unable to transfer accurate pitch.

Fortunately most computers today have an accurate quartz crystal frequency reference, so the 440 Hz is probably accurate, but not guaranteed.


A 6.4 cent error is equivalent to 3704 parts per million. Even a poor quartz crystal with poor quality external capacitors is stable to within 100 ppm - not nearly enough to explain a 6.4 cent discrepancy.

True, Robert. But I sent Anthony a photo of my two Android phablets propped against my laptop which was playing a nominal 440Hz tone. The new phablet showed dead-on, and the old one had the needle 6.4 cents sharp, both listening to the same source simultaneously.

(Love Tunelab too!)

With almost 16000 views and over 170 replies this thread quite interesting.

The error, in this case, was caused by the older tablet doing some rather unexpected things with a buffer. Basically it was trying to splice two non-consecutive snippets of audio data together into one array, which introduced an abrupt phase shift in the middle of the array.

Abrupt phase changes can do weird things when you're trying to measure pitch. For example, if you were taking an FFT and trying to determine pitch from the position of peaks in the frequency spectrum, the phase shift would cause a double peak in place of what would normally be a single peak, with the two peaks located sharp and flat of the actual frequency. It's similar to what you'd get if you tuned one string of a unison 6 cents flat and the other string 6 cents sharp.

Fantastic!

Why do I need a needle, because you have to keep track of the strobe disc? Maybe enable the user to turn off the needle?

I like having all three indicators! Needle, strobe, and blue dots.

Vlad, the reason I have not yet included an option to turn off the needle is that it is necessary for the very highest notes on the piano. If the top notes on the piano are significantly out of tune the strobe spins so rapidly that it appears to stop or spin in the opposite direction. See https://en.wikipedia.org/wiki/Wagon-wheel_effect Without the needle the user could be misled into thinking the note is sharp when it is actually flat.

A compromise I am considering is to allow the needle to disappear when the note is within +/- 10 cents of being in tune.