Digital recording affecting intonation??

Jim Cohen · Post by **Jim Cohen** » 15 Jan 2020 8:01 pm

Just discovered something pretty weird. At a recent performance, we videorecorded using two different digital devices, an iPhone and a Canon Powershot G9 camera. On one song I play a solo way up in Hughey-land and it sounds fine on the Canon recording but definitely sounds out of tune in several places on the iPhone recording. I thought maybe I was imagining things so I checked with my wife (a choral director, so she's very sensitive to intonation issues) - and she agreed with me.

I could understand it if it were two analog tape recordings with variable tape speed but how can this happen with digital devices??

Jack Stoner · Post by **Jack Stoner** » 16 Jan 2020 3:26 am

Sounds like bitrate or possibly one is compressed (MP3 audio format) and other is full wav audio? Just a thought as I don't know what format the iPhone uses for audio on a recording.

Bill Terry · Post by **Bill Terry** » 16 Jan 2020 6:24 am

+1 on what Jack said. No doubt some sort of 'lossy' data compression is likely in play, and that can create all sorts of audible artifacts.

Scroll down about half way on this page to the 'Common Artifacts of Lossy Compression' section. You'll find that there are all sorts of things that can happen that change perception of pitch, etc. The rest of the page is a good read as well.

https://www.soundonsound.com/techniques ... your-music

Howard Parker · Post by **Howard Parker** » 16 Jan 2020 6:46 am

Might also be camera position and reflections.

h

Jason Goodell · Post by **Jason Goodell** » 19 Jan 2020 5:12 pm

If pitch variations are happening on the iPhone I would consider the following things. #1 overloading of the mic causing clipping. #2 rapid movement the phone creating a doppler effect. Was the phone moving or vibrating, and or inline of a loud sound source?

Bob Hoffnar · Post by **Bob Hoffnar** » 5 Feb 2020 5:57 am

Both of those units have pretty crappy mics. They are also both different crappy so they would accentuate different frequencies. Room placement can have a big effect also.

You never mentioned how you listen back. If they are recorded at different bit rates your D/A conversion could affect the pitch.

The one thing to do is link up that Zoom recorder for the audio. Great mics built in and quality A/D-D/A converters.

Barry Yasika · Post by **Barry Yasika** » 26 Mar 2020 7:16 am

Did you happen to post them on Youtube? I'd be interested in hearing the difference. I've had sort of the same problem. If not, no worries I was just curious.