Hello everyone, I got a sansa clip + as a christmas present, and being an electronics engineer and an avid hacker, I decided to subject it to a few tests I use to determine the audio quality of the device in an objective way. Most people would merely listen to the device through the headphones, and this gives only limited subjective information about how well the dacs and headphone amplifier are reproducing sound. I created a binaural sine wave recording on my computer (using the freeware program SBAGEN ) with one channel having a 200hz and the other channel a 207.8hz tone (schumann resonance frequency).
When I played back and measured the left and right channel frequencies coming out of my computer’s sound card using a radio shack 22-811 multimeter, they were correct. When I played the tone on a Muvo V100 player which I use as a reference, the frequencies were also correct. However, when I played the tone on the clip +, the frequencies measured 208.3 and 200.5 hz, a 0.5 hz frequency offset ! On the oscilloscope, my computer and the muvo were putting out very clean sine waveforms, but there seemed to be just the slightest amount of extraneous noise on the output of the clip. This 0.5 hz offset is comparable to a cassette player that has a motor that runs just a smidgen too fast, in other words the playback of the clip is slightly sped up.
I know that this may seem like a small nitpick, and compared to all the other portable media players that I have tried, the sansa clip + has the best subjective sound quality.Also I did the same test with two chinese rk2608a rockchip players and they were incapable of even reproducing an undistorted sine wave, so no measurement was possible…
Is this a hardware bug in the design of the codec, or could this be patched in the firmware? This might seem like a nitpick, but there are fanatical audiophiles out there who might consider this an issue!