Headphone Amp Channel Balance ABX Test

[artburda]

I wanted to find out if I can hear a channel imbalance of 0.5 db and 0.25 db when listening with headphones. In order to simulate a channel imbalance I recorded some sounds with a mono microphone, duplicated the track in audacity and exported it with identical left and right channels, +0.25 db on the right channel and +0.5 db on the right channel. Then I used the ABX test in foobar.

What do you think? How much channel imbalance is acceptable? Do you correct an analog volume pot imbalance with DSP or how do you deal with it?

With my Topping L30 I found a volume pot position around 11:30h, where the imbalance is only 0.05 db, and for volume adjusting I use the digital monitoring volume control on the Motu M4.

Here are my audio test files: https://we.tl/t-KOENBrIRs5

Here are my listening test results:

foo_abx 2.0.6c report
foobar2000 v1.6.2
2021-01-01 21:15:22

File A: 0.0 db.flac
SHA1: 09ac649f010fd55c392e82d33d75168c98aaa673
File B: 0.5 db.flac
SHA1: b4b92931937298bd35881477d5a5f4a2a96b1c0c

Used DSPs:
Resampler (dBpoweramp/SSRC)

Output:
ASIO : MOTU M Series
Crossfading: NO

21:15:22 : Test started.
21:15:35 : 01/01
21:16:08 : 02/02
21:16:47 : 03/03
21:17:46 : 04/04
21:18:08 : 04/05
21:18:16 : 05/06
21:18:23 : 05/07
21:18:47 : 06/08
21:19:07 : 07/09
21:19:33 : 08/10
21:19:33 : Test finished.

----------
Total: 8/10
p-value: 0.0547 (5.47%)

-- signature --
67aa97feb21c320f91d912259ee80221d13626e9

and

foo_abx 2.0.6c report
foobar2000 v1.6.2
2021-01-01 21:20:32

File A: 0.0 db.flac
SHA1: 09ac649f010fd55c392e82d33d75168c98aaa673
File B: 0.25 db.flac
SHA1: 2baa949f2466a27fb86b3baaa47e9b6c7b0f6f4c

Used DSPs:
Resampler (dBpoweramp/SSRC)

Output:
ASIO : MOTU M Series
Crossfading: NO

21:20:32 : Test started.
21:20:57 : 00/01
21:21:49 : 01/02
21:22:15 : 02/03
21:22:41 : 03/04
21:23:05 : 04/05
21:23:44 : 04/06
21:24:32 : 05/07
21:25:15 : 05/08
21:25:25 : 06/09
21:25:48 : 06/10
21:25:48 : Test finished.

----------
Total: 6/10
p-value: 0.377 (37.7%)

-- signature --
1db7013e4021d8cab8a0393a258c55e8d60b961a

 

[ADU]

Older topic, but thanks for sharin these results, artburda.

My source is a computer. And my amp and other gear does not have L/R balance adjustments. So I just use the (digital) L./R stereo volume controls in my computer audio device's properties to try to correct any imbalances in my other gear.

My headphones are reversible. So what I will usually do is play a monophonic signal (generally pink noise, but sometimes also mono music recordings), and then flip the headphones back and forth while reducing one of the L/R volume controls (whichever channel seems loudest), until the headphones sound centered approximately the same in both orientations.

My hearing unfortunately has its own imbalances, due to more loss at certain frequencies in one ear. Reversing the headphones with a mono signal helps to ensure that the channels are correctly balanced on my gear though, even though my perception and hearing may still be slightly off center.

There have also been times though when I've used EQ with separate left and right controls to try to correct both the imbalances in my gear, and also in my hearing. This can help with imaging. But it also sounds a bit unnatural, because it's not the way I normally hear things in everyday life. So that's why I tend to focus on getting the balance correct on just my gear.

 

[ADU]

Since I'm making some tweaks to the volume on my PC with the digital controls, both in the audio properties and also via EQ software to correct other tonal balance issues, I will also set the bit depth on my audio device higher than the usual 16 bits to improve the resampling of the audio levels.