Recently I have noticed that there have been a growing number of searches coming to my blog that relate to fixing phase problems. Although I have mentioned the importance of phase in recording I do not believe that I addressed fixing phase problems.
Ok let’s get started. You have a multitrack recording and somewhere there seem to be phase problems. Are you sure? Probably not. Let’s review for a second.
Phase is caused by two or more microphones being used on one item that you are recording. In some cases the varying distances between the mic cause the sound waves to line up peak to trough and this means they are out of phase. If you are in the process of recording this sound then you fix the problem by moving the mics around until the sound falls into phase. Also it should be noted that EQ adds phase problems to any signal it is used on. This is an absolute as far as I am concerned although I have been corrected by engineers on this point they are wrong and I am right damn it. If you add EQ it adds some phaseyness. Usually this is acceptable and part of the sound. Sometimes too much EQ makes a thin phasey mix. How do you fix this problem? Drop all of the EQ it’s that simple.
The most common situation for phase problems is recording multiple tracks of one particular instrument on one pass. When do you do this? Every time you cut drum tracks. So let’s assume that you cut four simultaneous tracks of drums last night and know it’s time to mix and damn it sounds out of phase.
The first thing you do is prove it to yourself. Drop every track except one. Now listen carefully. Does the track sound fat? Does it have bottom? It does, ok move on to the next track. Most likely all of the individual tracks will sound fat and have bottom. Now start putting up combinations of tracks two at a time. One you happen upon one combo that sounds thin, phasey and has no bottom mark it down and move on. There may be multiple problems. Sometimes, but not usually the problems may be between two tracks recorded at different times. Remember listen closely. You are looking for thin sound with no bottom. If you are unsure what phase problems sound like put up a track and then switch the positive and negative wires on your studio monitors. Step back away from the speakers and play the track. That’s the sound of a phase problem.
So now you know what phase sounds like and you have two or more tracks that are definitely out of phase with each other. Can you rerecord? No ok then let’s fix it.
In all likelihood the sounds are not perfectly 180 degrees out of phase. They rarely are. It doesn’t matter. If it is enough of a problem to be heard as out of phase correcting the phase will help. In short what you need to do is reverse the phase on one track and then listen. Does your board or software have a phase switch? If it does you are all set. Switch the phase on one track , it doesn’t matter which, and then listen to the offending tracks. When it comes into phase you will hear much more bottom and the thin wavy quality will disappear. If you have more than two tracks at issue you may need to mess around with various combos of phase switching in order to find the best phase situation.
What do you do if you don’t have a phase switch, which is common with many boards. Does the board have an insert section with paired plug ins/outs? In this case you take a cable open one end up and cut the two or three wires. Switches the connections on the positive negative. Now use this cable to flip the phase on the individual channels. Use the same process I outlined above.
What do you do if you have a board with no phase switch and no insert section? Shot yourself? No, calm down. Try doing the same trick with a basic guitar cable. Then send the sound out of one channel and record it on the next open track with the phase reversed.
Now I will address the more complex method since someone that thinks they are smart will certainly post a comment about it. I may even decide to approve said comment if it contains a good joke or the new home phone number of my high school girlfriend.
There are phase relationship altering outboard and inboard equipment. They allow you to dial the phase around 180 degrees. They are magic. Let an engineer run them, preferably an engineer that would never record two tracks out of phase.
Finally I’ll talk about phasing in a mix. A depressingly common problem is a mix that sounds shitty. It sounds muddy, or phasey or both. How do you fix this? Well if you are trying to fix a mix that is done and is a stereo master than take it to a good mastering house. If you are trying to fix a mix that you are working on then there is still hope.
Let’s say you have a home studio. You do a mix. The next day you take the CD of the mix and pop it into your car stereo and, jeez, does it sound like shit. Don’t worry everyone does shitty mixes. It’s only a problem if you release it to the world.
Ok try this. Put up the mix. Eliminate every EQ that is engaged. This alone may solve your problem. After you remove the EQ’s the sound may very well clear up. Try running a mix with no EQ on anything just rebalance the tracks and call it a mix. No compare the two. Which one sounds better? The most common problem I have seen in mixes is too much EQ. If this doesn’t help the mix try adding the tracks one at a time listening specifically for the phase problem to appear. When you find the offending track strip it down to the basic track without effects. How’s that? If it isn’t caused by some kind of outboard effect then the most likely problem is that the offending track(s) sound too good. What!!??? That’s right. A common problem with recordings is that every single track is recorded as if it the only track on the recording, that is to say tons of bottom, tons of mids tons of top. If you do this on every track then the mix will sound like shit. Remix engineers make great money taking multitrack tapes and removing various frequencies in order to make them sound clearer. Try removing a little bottom from a few tracks with the eq. Try cutting some of the mids. EQs are much more beneficial when used to remove frequencies then when they are used to add frequencies……..
© Brad Morrison/Billiken Media 2010