Portable Audio Recorder Noise Tests

We've reviewed ten handheld WAV recorders so far, and one of the most common questions we get is "How good are the mic preamps? I don't want to pollute my recordings with hiss."

You can get a good idea of each recorder's sound quality from the numerous audio examples Mark Nelson posts with each review, but Brad Fuller just pointed out a site where they've done some detailed lab-coat tests. Avisoft Bioacoustics specializes in scientific field recordings of wild animals, so preamp noise is especially important. On its Microphone Input Noise Comparison chart, it offers test results for a number of popular recorders.

Of particular interest is this note on the page explaining the results:

The specifications provided by recorder manufacturers are often difficult to interpret. Due to marketing considerations, many manufacturers tend to publish large dynamic range numbers (e.g. > 100 dB) that are only valid for high-level signals.

The dynamic range is the ratio between the maximum signal level...and the inherent noise floor of the recorder. Therefore, this figure depends on the device-specific input headroom ...that is usually of little importance for recording soft animal sounds. In other words, the dynamic range does not necessarily tell anything about the noise performance of the recorder.

For instance, the microphone input of the Marantz PMD671 is honestly specified with a "poor" signal-to-noise ratio of 65dB(A), while the M-Audio MicroTrack claims a dynamic range of 100dB(A). However, a practical side by side test reveals that the PMD671 provides a significantly lower inherent noise level than the MicroTrack2496!

These specs are a great complement to Mark's hands-on reviews, which focus on musical quality and ease of use, something that's hard to measure in a lab. The Avisoft site also has lots of background on field recording equipment and techniques. You can even hear ultrasonic rat vocalizations, transposed down to audible range.

(Thanks, Brad!)