At the bar where I work, we usually play vinyl, but on busy nights we use a tablet with downloaded albums played through Samsung Music. The tablet and sound system have been in use for about five or six years, and nothing else seems to have changed.
A few weeks ago, I noticed that the vocals were missing from one song on a Nancy Sinatra compilation. The instrumental parts sounded completely normal, so I assumed it was a strange one-off. However, more songs from that same album have gradually developed the same problem. In one duet, Nancy's voice is missing while Lee Hazlewood's part still plays normally. Roughly a third of the album is now affected, and once a song loses its vocals, they do not seem to return.
No other albums are affected, and the rest of the sound system appears to work normally. What could cause only the vocals to disappear while the instruments remain audible?
4 Answers
Check whether the bar's system is mono, stereo, or using a center channel. When stereo audio is combined into mono, phase or polarity problems can cancel centered material almost completely. A bad cable, connector, headphone jack, amplifier input, or speaker could cause this. If you can hear vocal reverb but not the main voice, that would especially suggest phase cancellation, since the dry vocal is usually centered while the reverb is spread across the stereo field.
If the system has surround speakers, make sure the center speaker or its connection has not failed. Dialogue and lead vocals are often routed to the center channel in surround setups, so losing that speaker can make voices vanish while the rest of the mix continues playing.
It is worth checking the music player's settings for a karaoke, vocal-removal, balance, mono, or accessibility mode, especially if the tablet received an update. Still, because only one album is affected and different songs behave differently, a channel or phase problem in the sound system is more likely than a software setting.
The most likely explanation is that one stereo channel is missing, inverted, or being canceled out somewhere in the playback chain. Vocals are often mixed in the center of the stereo image, while instruments are spread left and right. If the system is losing a channel or summing the channels incorrectly, the centered vocals can disappear while much of the music remains. Try the same files with headphones, another speaker system, or a different music app. That will show whether the files are damaged or the problem is downstream of the tablet.
That makes sense. I will test it with headphones and the tablet's own speakers after my shift. Do you have any idea why the problem seems to be spreading to more songs over time?
If one speaker or connection has failed, you may only notice it on tracks where the vocals are strongly centered or panned in a particular way. The album may simply contain more mixes that expose the problem; the files themselves may not be changing.
A headphone test is a good first step, although it may not reveal every polarity issue. Testing the tablet directly with headphones and then testing the normal sound system separately should help isolate where the cancellation occurs.