Just a few days ago I had a interesting thing happened which proved to me – again – that mono compatibility is still very important, yet most of the time it’s overlooked or simply ignored. Many even make jokes like “mono is dead”, etc. but here I would like to remind everyone that mono is still here and going to be here no matter if we consider stereo or multichannel immersive formats.
Little change, big problem
The first day on the main stage we just started the soundcheck with the band, when the lead singer told us that something is weird in his in-ears. It is like the backing vocal track, which comes from a multitrack machine would be off. Only a tiny bit, but it’s large enough to hear. The guitar player also noticed the strangeness, but he thought he might just drank too much last night. No one really knew what was that, so the soundcheck just finished, everyone was happy.
The show went really well, except, in a few songs the lead guy seemed really confused, even off the beat sometimes. This was really strange as in his case this almost never happen. After the show he told us he felt that in certain songs the multitrack backing vocals were off. Obviously it can be quite disturbing while you sing.
This was very strange. Half the band is on in-ears, half of them use wedge monitors. Only the in-ear guys had this unpleasant experience.
The next soundcheck we decided to investigate this issue a bit, so after we had everything set up, we double checked everything, checked the multitrack but found no problem at all. Then during the soundcheck, the musicians with in-ears told us that they have the very same problem, the multitrack is offbeat in certain songs. Now comes the really weird part. We stopped the soundcheck in order to find the root of the problem. Checked that few songs, and through the wedges, everything seemed to be fine. No offbeat or delayed things, everything is fine. While the musicians on stage with in-ears still hear a somewhat delayed backing track.
Started with the laptop, we checked every possible thing from the DAW through the soundcard’s output patch to the multicore. Even double checked each other, but nothing.
Borrowed one of the in-ears I just went through the songs again, and my jaw dropped. Certain songs had offbeat backing track. Re-checked it, but in the wedges it was all good. Spooky!
And then the penny dropped
A quick check on the monitor board revealed the only difference between the wedge and in-ear mixes. First of all, the wedges had very little backing track, and even if they had, only one side of the stereo signal had been used for monitoring, while in the in-ears, the monitor engineer used both sides. Apparently, all the in-ears are in mono though!
That was the point where I was sure it is the good old thing. They made a so artificially wide stereo backing track that it collapse in mono, and the only thing you can here in mono is some weird delayed phasing thing, which seems out of time of course, as you cannot really here the fundamentals, only the effect part.
As soon as I removed one channel from their in-ears the problem disappeared! It was all good again.
Obviously this is not a mysterious thing happened without human interaction. A small chat with the band leader revealed the root of the problem. He changed a few arrangement on the multitrack, deliberately made them “unbelievably wide stereo” and it sounded awesome on stereo headphones.
Well, it might have sounded great on isolated headphones, but as soon as the material played back in other format (mono), a huge part of the original sound disappeared.
So what’s the conclusion?
If nothing more, than that we still have to consider the good old mono. With clever arrangement, widening and stereo tricks we can maintain very wide stereo effects which still lives happily in mono. You might loose a tiny bit of that extreme wide effect, but it is still better to loose a tiny part than have a train wreck.
Consider mono, check it, and work on your material to be compatible with every possible scenario. A bit harder to achieve, but sonically it’s rewarding.
So, problem solved, the band is happy, their stereo effects still sound extremely wide but now, it’s working in mono too.