Phase check download track(s)?

[Dave2002]

Are there any download tracks, preferably free, which would enable me to verify the phase of a pair of loudspeakers for stereo?

I have had to cut a cable because at one end it had a DIN loudspeaker connection () and the cable itself is tightly wedged behind a bookcase. My hope that I could pull the cable through with string attached, and pull it back again later has proved completely misplaced.

I've improvised the required cable using the DIN connector end, but I'm not sure which way round the new cable should be attached to the amplifier - I can easily reverse the connections by swapping the red and black plugs at the other end.

If I have time I could also check the continuity with a meter - that might actually be a better way, but if there are any phase check tracks - like the ones on that old John Borwick LP, that could be helpful.

[johnb]

PM on its way

[OldTechie]

These seem to work: http://www.audiocheck.net/audiotests_polaritycheck.php

I prefer the guitar one. You can download them as well as play them.

There are all sorts of test sounds on the site.

[Dave2002]

I just got round to checking the connections I made electrically - using a torch. It appears that I got it right, but doing the phase check aurally was not as easy/obvious as I'd hoped. Listening to tracks on my laptop it was easy to identify the in-phase versus the out of phase configurations, but with loudspeakers in a domestic environment this was not so easy.

At low frequencies (say 50 Hz), the wavelength is about 20 feet, so the difference in distances to the speakers to bring out of phase signals back into phase would be around 10 feet, which with loudspeakers say 8 feet apart would mean that listeners would be outside a rectangle based on the line between the speakers, and going back into the room. However, human hearing is not so sensitive at low frequencies, and other factors, such as reflections would complicate the impression gained.

At higher frequencies (say above 250Hz to 1 kHz), the wavelength would be between 1 and 4 feet, and the half wavelength 6 inches to 2 feet.
Human hearing is more sensitive in this range. It would now be quite easy to find positions where there would be selective reinforcement or cancellation depending on location.

Stereo effects depend on amplitude and phase, and also on tonal characteristics, and the perceived effect for any recording may depend on how the recording was made. This would most likely affect signals from instruments in the centre of the sound stage, as sounds to the left or right would not have large amplitude components in the other channel. Ambience would be affected also.

I was reminded in this exercise that listening in domestic rooms is unlikely to be ideal, and that pin point accuracy of spatial location by aural means is nearly impossible.

[johnb]

Dave, in my experience the differences are very obvious when using the "Pink noise bands and phase check , Bass 0 - 220Hz & phase check" track that I passed to you.

When sitting in the appropriate location there is a marked drop in the perceived low frequencies when the channels are out of phase.

[Dave2002]

johnb

I think a lot depends on the environment, and perhaps also on the speakers used. The particular speakers are light on bass, but otherwise I still believe very good. Also the particular listening environment I used was not ideal, with a tiled floor and quite a few glass surfaces, so reflections may have been the order of the day, though probably not many resonances. The room itself could have had standing waves at around 55 Hz and 120 Hz based roughly on dimensions - approx 4 metres by 8 metres, with varying height.

Nevertheless, despite these factors, plus maybe also my own hearing deficiencies, it still seems I got it right, but my point is that it may not always be easy.

I may revisit this again, before putting the speakers back in their original locations in another room.

[Lordgeous]

There's some on this site:

http://0339436.netsolhost.com/WordPress/lp-recordings/