Monday, October 27, 2014

News: Binaural speaker recordings

When I had the idea of doing "fidelity-tests" of various speakers, I quickly noticed that it wouldn't be that easy to achieve really representative results.

Apart from room acoustics etc. the microphones have a too strong self-sound, to really allow valid results. I had tested more than half dozen different handheld recorders, from Olympus to Yamaha and Zoom. And all of them sounded so different that I doubt they would allow any neutral results.
To give it another try, I lately ordered a Zoom H5 and an optional XYH-6 capsule as I hoped these would give me significant improvements over the "cheap" Zoom H1 recorder that I am currently using, but in the end, the results were even worse. Not only did both mic-capsules emphasize treble too much, they did roll-off with low frequencies too strong, and there was a noticable divergency between left/right channel with the sound being not centered as it should be. Both microphones had a different bias towards left or right, therefore I sent both back totally disappointed.
Currently it seems as if I was still at the very beginning to find a better but still affordable recording solution which would allow the most neutral and flat recording.

You can hear some of my previous test-recordings here. In this case the JBL Charge 2 was recorded with all recorder/microphone combinations in the same room with the same settings/distance etc. As the XYH-6 capsule supports 2 different directional patterns, I did recordings with both, you can also check out the original track for comparison:

Excerpt of the original track:

Zoom H1:

Zoom H5:

Zoom H5+XYH-6 90°:

Zoom H5+XYH-6 120°:

I think it is pretty obvious that all the used microphones have a different sound, there is even a noticeable sound-difference between the 90° and 120° setting of the XYH-6 capulse. I also tried a recording with my current measuring microphone the MiniDSP UMIK-1, but so far I am still in the process to include the calibration file into the recording procedure and will post it as soon as I managed.

At the same time, I had also ordered a Roland CS-10EM binaural microphone. I wanted to try out something new and although these microphones are not really suitable for neutral direct recordings of a speaker, they seem perfectly suitable to record how a speaker would sound in a particular room thanks to a rather neutral sound. You have to wear headphones to hear how the sound was meant to be, or you can try playing it back through speakers with a crosstalk cancelling filter like "Liveaudio" from the Mini Jambox.

To understand better how the listening situation was, what kind of room etc, I also did a photo of each listening position, so that you can see what I heard when I did those recordings wearing the microphones inside my ears. I am curious what you think about this kind of audio-demo, and if I should continue using it in future for further speaker comparisons too. I did not normalize the recordings, so the difference in loudness you hear is real and represents the real situation.

Again I used the JBL Charge 2 (my current portable reference despite all the distortion issues, it is one of the best sounding portable speakers which can be already had for 129€) and recorded it in different rooms and positions from different distances, please have a look (and don't forget to listen through headphones):

Equally to the JBL I also tried recording some further speakers inside the shelf in the living room, I wonder if you can hear the difference in sound between all of them. I think that especially the increased stereo-separation of the EVA Blu and the Bose compared to the JBL Charge 2 and the mono Play:1 is pretty obvious:

Please let me know what you think about these recordings. Does the binaural effect work for you? Do these recordings sound more real than the previous ones I did? Which listening position does represent the most realistic situation for you?

Please leave a comment if you have further ideas!

1 comment:

  1. living room shelf 1.3 m seems the most appropriate test.

    cannot comment on the different microphones, as there seems to be too little of a difference among them (and all sound very different from the original source).

    PS listening on mac, with Senheiser headphones