So this is a blog in the continuing series covering recording techniques, gear, attitude, strange events in the studio etc. The last blog was a run down of a track explaining how it was recorded. Tonight I think I will continue on talking about different pieces of electronics in the studio and how they are used to create pro sounding tracks.
Since I have covered microphones extensively I will tackle the next step in the chain, the microphone preamplifier, commonly called the mic pre. The Mic Pre is an extremely important piece of the puzzle. It is exactly what it sounds like, an amplifier for the microphone. The signal from the mic travels down the wire and enters the board. Here is where the Mic Pre does it’s magic. It is a little, very powerful amplifier circuit. On the top of the board you have a simple volume control. As part of the section dedicated to the Mic Pre there are often a few other controls. One may be labeled “Phantom” or “+48”. This switch turns on the phantom power. I covered this in an earlier blog so you can refer back to more in depth comments but let me just say that most condenser microphones require power. This is supplied by the phantom power system of the mixing board. In some cases there is one switch on the back of the board that turns on the power for all mic pre’s and on other boards there is an individual switch for each channel. If the power is not on the mic will not work. If it is on and the mic doesn’t require power it will have no apparent effect. Another possible control on the Mic Pre section is the Phase switch. This is an extremely important switch and is often ignored or misunderstood by users. This is unfortunate since it has a really specific use that, once you understand it, can really solve certain recording issues. The switch is usually labeled like this ø. I have even seen it labeled like this ∞. which is completely wrong. There are other places on boards where the second symbol, the symbol for infinity is appropriate. The Phase switch just isn’t one of these places.
The concept of phase in recording is important so follow along closely. Sound is made up of waves. Just like waves in the ocean the sound waves have peaks (high points) and troughs (low points). If you take a piece of paper and draw a perfect series of up and down waves with nice round curves that are all exactly the same you will have just drawn a sine wave. There is no need to discuss the math involved with a sine wave but just know that you can write out this wave using math.
That’s what it looks like. Now let’s imagine that this sound is being played into a mic which is running down the wire and entering the mixing board through the Mic Pre. Now we switch the phase switch.
This reverses the phase of the incoming signal. Now the peaks are where the troughs were a moment ago. Since we are also listening in this imaginary scenario where we have an imaginary signal going into our imaginary board with our imaginary phase switch and the world is ruled by Damn Dirty Apes! Fight them! Be proud you are human dammit!!! You think all of those bananas in the super market are just a coincidence? No! It’s a conspiracy!… Sorry I got off track for a second. I am prone to losing track of fantasy scenarios.
Right so we are listening. What change do we hear? None, nothing, zip, nada. The phase switch just changes the way the signal is being processed. Since we are hearing a wave form that is identical except for the placement of troughs and peaks we hear the same boring sine wave. (a sine wave sounds like a really boring flute tone)
Now let’s imagine that we have two sine waves being played into two mic pre’s side by side. We are listening to these two signals in the monitor speakers. If these two sine waves entering the board with their phase patterns just like the two illustrations above, that is to say, where the peaks and troughs of the two signals would be opposite from each other we say that they are “out of phase”. Since sine waves are mathematically perfect and regular if we actually try to listen to two sine waves that are “out of phase” with each other than the result is —————- Silence. The peaks cancel out the troughs and the troughs cancel out the peaks. This is caused by the signals being “perfectly out of phase”. In math terms they are 180° out of phase. It doesn’t matter if you don’t quite get the math argument for this situation. What is important is that you understand that peaks and troughs are interfering with each other and it is changing the sound. Let’s take this stuff and apply it to music.
Let’s say that you have a bass being recorded by a mic on track 3 and a guitar being recorded by a mic on track 5. What happens when these two instruments and tracks are out of phase? Nothing. Why? Well it’s sort of a trick question. The two instruments are being recorded separately on two different mics on two separate tracks. In this case what the phase of each track is doesn’t matter. PHASE ONLY MATTERS WHEN YOU HAVE TWO OR MORE MICS RECORDING THE SAME SOUND. When there are more than one mic catching a sound then the possibility comes up that the troughs and peaks of the sound may be out of alignment with each other. Let’s look at a situation that comes up often in the studio.
You set up a drum kit and put mics all around the drum kit to capture all the different pieces of the kit when you drummer finally gets out of jail, finishes fighting with his girlfriend, wolfs down the meatball hero her borrowed 7 dollars from you to buy, drinks all of your beer while your not looking and then finally decides to put down that smokin’ groove that opens your latest masterpiece “Fish eye soup”. Every hit of the snare or the kick or the hi hat or the cymbal will be picked up on all of the mics. Each mic will get more or less of the sound. This doesn’t matter and doesn’t cause the problems. All of the mics will receive some of the sound of the snare drum hit at SLIGHTLY DIFFERENT TIMES.
The key here is to understand that the little graph is the pattern of a sound plotted ALONG A TIME LINE. So when peaks and troughs end up canceling each other out it is because the signal is happening at a slightly different TIME.
Get it? It’s ok if it’s a little fuzzy. What counts is that you learn a couple of simple rules and then learn to THINK about what is going on with your mics and channels. Then you can figure out when you might have possible phase problems
Here’s the rules:
1. Phase problems happen when two or more mics catch the same sound at different times.
2. Phase problems can also happen when two or more tracks are playing back the same sound with different effects on the different channels.
If you know these two rules then you will know when to suspect that the EVIL MUNCHKIN GOD OF BAD PHASE IS HAUNTING YOUR RECORDING. So now you suspect that the munchkin god is consuming your drummer’s soul. Damn that sucks. How can you be sure? How can you fix it? Easy.
Let’s say you think two mics are out of phase. They are both pointing at the snare drum. Listen to the two mic channels by themselves together. Does that make sense? Ah, let me put it in better Engrish. Press the solo buttons on both channels or turn all the other channels down so that you can only hear those two mics while the drummer plays a beat. Now, listen while he plays and SWITCH THE PHASE BUTTON ON ONE OF THE CHANNELS. It’s got to be one of the channels not both. If you switch both you will just create the mirror image of the same problem. [ Deep Purple’s Highway Star just started on my Ipod. It smokes…Man can Ian Gillian sing the high metal god shit!] So when you switch the phase button listen to see if more bottom appears. That is to say more bass frequencies, more low frequencies. The most obvious sign that you have a phase problem is that the sound will be thin with no bottom. It may also have a flangy, phasey kinda sweep sound changing as the sound goes on. This happens sometimes not always but the lack of bottom is sure sign. If you find that pushing one of the phase buttons in gives you more bottom in the sound then the two mics were out of phase. You can leave the button pushed down and record that way OR you can move the mic slightly to try to find a sweet spot that doesn’t suffer from phase problems. Both solutions work well.
What if your mixing board doesn’t have a phase button? It happens. I recorded two records on an extremely expensive English mixing board that had no phase buttons. In that case you soldier together a wire that switches the phase. If you need an explanation of how to do that post a comment or write me an email.
It’s extremely important that you learn to identify and eliminate phase problems when you record. This will help you tracks sound fat and happy. I need to add that all recordings of multiple instruments using multitrack recording are going to have some phase problems somewhere in the mix. It’s impossible to get everything to be “perfectly in phase”. You only need to eliminate glaring errors. Get in the habit of checking for phase and moving mics, switching phase buttons to try to police these things out of your recordings.
I once was asked to do a mix at a semi pro studio in Albany,NY. I was remixing some figgs tracks and another band offered to pay me to remix one or two of their tracks to hopefully make them sound a little better than the mixes they had. I listened to their mixes and they were really muddy and it was hard to hear any individual instrument. I suspected that they were using too much EQ when they mixed. I turned up in the studio and asked them to pop in a CD of “Zeppelin’s “Houses of the Holy”. The studio owner/engineer was really testy about me even working in his studio and lectured me about being careful not to break anything or mess up the careful set up and balances of all his gear. At first he was really annoyed that I wanted to listen to Zeppelin. Eventually he put in the disc. I cranked it up and listened for about thirty seconds. I then clicked through about 20 seconds of a few different tracks.
I got up from behind the board and opened the closet that was next to the wall where the monitors were mounted as recessed units. I reached behind one of the monitors and reversed the wires on one of the speakers before he could stop me. He was furious. An argument ensued. While he was still yelling at me I hit play on the Zeppelin CD and turned it up. He stopped dead in his tracks. It sounded great and he knew it.
His main monitor speakers were out of phase. He had one speaker wired with the positive wire to the negative and the negative wire to the positive terminal. If he had wired both speakers wrong he would have gotten it right but he had miswired one of them. For over a year he had been charging local bands decent money to mix recordings on an out of phase speaker system. As a result every band put tons and tons of added bass and bottom on their recordings. When they got home the recordings sounded like crap, muddy, indistinct and boomy. He had heard the complaints and thought that the bands were all idiots.
When his ego had recovered he apologised and offered to make the session free. A few days later I was interviewed for the local arts paper. They asked me what I thought of the studio and I said “It sounded great! Our mixes came out great!” which was true. It doesn’t help to buy $2000 monitors and then wire them wrong. The simple methods I have just outlined are easy to learn and will help you insure that your mixes sound good. There are pro tests using oscilloscopes and other do dads but leave that kind of stuff to pro engineers…..
So the next piece of the recording puzzle is the next piece of the recording chain, the compressor. If you have read many of my other blogs you’ve heard me mention these items in various ways. This is the most underused, overused and completely misunderstood piece of gear in the recording studio. (or on stage for that matter)
I love compressors. It didn’t always love them. I came to love them slowly, over time. I always used them but it wasn’t until I started to attend mastering sessions with high paid mastering engineers that I started to fully grasp their power and understand why they were so damn cool and so important to making a smoking rock record.
In 1997 or 1998 (my memory is poor) I won the RIAA Rock Record of the Year for producing Graham Parker and the Figgs “The Last Rock n Roll Tour”. I was flattered. I was a little confused since I felt I had made more important records and that some of the records I had made sounded better. Like all stupid award kinda things it had to do with Public Relations, the way the wind was blowing in the rock business and all kinds of strange useless trends that added up to me winning over lots of people with huge names working with huge acts.
I remember turning up to the mastering session (mastering is where you go to a pro studio to adjust the EQ and Compression on a whole record. You should end up with a pro sounding recording) [Red Baron by Billy Cobham on the Ipod now. The electric piano solo is ridiculously good] The mastering Engineer set up the tape and hit play. Then he turned to me and joked ” So do I even get paid for this?” He was flattering me. The record was mixed really well.(thanks to Eric Rachel who helped out) and it was compressed so much that the needles on the main meters shot up to +1 and stayed there for the whole record. This is a good thing for a rock record. what i had done was compress the mixes. This makes them sound great. (Here’s graham and the figgs at South By Southwest 2007)
When MIX magazine interviewed me about the record the first question the writer asked was ” This record is slammed. How much of that was done in the mix and how much did you add in mastering?” Again, the point here is that the writer knew that the reason the record sounded so damn loud was the compression.
So what is it? What makes Compression and Compressors so important? Let’s look at the gear and I think we can find and answer.
Compressors and limiters do two basic things. Limiters limit how loud a track or track is allowed to go. Compressors on the other hand make loud things softer and soft things louder. That’s all. It’s simple really.
When you take a sound and put it through a compressor unit it changes the dynamics of the sound. It takes the louder parts of the sound and pushes them down and it takes the softer parts and pushed them up. It squeezes the dynamics together.
From the standpoint of how it stands it makes the sound stick out. It gives it an “in your face” quality. The harder the compression the more obvious the effect of making it push into the front. Heavily compressed music has a tendency to jump from the speaker. It makes a voice, for example, pop right out of a speaker. The vast majority of classic records that you and I love are compressed. They are compressed when they are recorded. They are compressed when they are mixed. They are recompressed when they are mastered and often, when remastered they are compressed yet again.
Many lousy engineers have railed at me, usually at length, about the evils of compression. They seem to be fundamentally opposed to the idea on philosophical grounds. Their rant usually goes something like this:
“I never use them. I like my music to breathe. Why would you want to take any of the dynamics out of music? Dynamics are what make music sound real!! I hate compressors. Only lazy engineers and producers use them to cover the fac that they don’t know how to record!”
This rant is the exact opposite of the truth. In my experience the philosophical rant from anti compressor engineers is cover for the fact that they do not know how to use a compressor and as a result whenever they have tried to use them one of two things happens, they either have no effect and this leaves them confused or they make the track sound duller and this leaves them confused. So they make up a speech about the importance of dynamics.
Dynamics, the loudness and softness, in music are, of course, important. In the world of recording classical music musical dynamics are taken extremely seriously. Classical recordings often sweep from a whisper to a crashing crescendo. Classical recordings rarely use any compression. They stick to the absolute scale of dynamics. (that’s a complex argument that I won’t get into, just accept it and let’s move on) This is inappropriate for rock music. In the world of rock recording the trend through the years has been towards more and more compression.
In 1993 I hired Don Gehman to produce the Figgs for Imago/BMG records. Don has produced lots of hits. The Bee Gees, John Cougar Melloncamp (that self-righteous prick), Hootie and the Blowfish etc. Don is a decent engineer and that is his main contribution to “production”. He has certain technical tricks and methods and if you add all of them up that’s his “sound”. One of these tricks is Bus Compression. This is his trick alone but he is one of the converted ones that will fight to the death for Buss Compression. What the fuck is Buss Compression?
When you are mixing down a multitrack tape into the final mix that will be released to the world the final two stereo tracks that are coming out of the mixing console and being recorded as a mixed two track tape or stereo file on a computer are referred to as the Stereo Buss. This is just the two tracks that make up a mix, right and left. The main outputs of the mixing board, left and right are the Busses. This is a bit of a misuse of the term but we won’t worry about that just accept that when an engineer talks about the stereo busses he is referring to the stereo signals that come out of the mixing board. Is that clear? I’m not certain I can explain it any other way.
Don and I and most of the producers in the rock world send this mix into a stereo compressor and compress the whole mix before it gets recorded as a final mix. This is called Buss Compression.
I remember turning up at Dreamland Studios in Woodstock NY in 93 to check on the Figgs album project. Don took me in the main control room and cued up a mix. He hit play and the mix blared out. He had a twinkle in his eyes and he was pointing at the meters for the final mix. They were old fashioned big meters with real needles. I kept looking at them and shrugging. I had no idea what he was trying to tell me. Finally he stopped the tape so I could actually hear what he was saying.
“That’s what I call compressing for success!!” he joked. He then hit play again. The needles Jumped up to +1, wavered for an instant and then just stuck there quivering as the mix played on. His point was that the mix was compressed so hard that the recording jumped up to maximum and stayed there. Later he commented that mastering engineers loved him since he did all their work for them. When you compress a signal, track, mix, microphone input etc heavily it is called Slamming it. Well readers prepare to Slam the Shit out of your recordings!
The reason that many people shy away from compressor and often misuse them when they do use them is that they don’t understand the basic system and controls of a compressor. You guessed it, I’m going to cure you of that problem right now.
When a signal enters a compressor the compressor squashes the sound. It takes the soft bits and makes them louder and it takes the loud bits and makes them softer. It is pushing everything towards the middle of the VOLUME CURVE. It looks like this:
The signal in the picture is our friend the sine wave again. Notice that there are three sections of the graph. The Attack, the middle section which is just the signal while being compressed and the release. When you look at the front of a compressor you will find (not on all but on some) controls that say things like attack and release. There is also two important ones called threshold and ratio. Some simpler units may just have ratio and threshold. The final control knob, or dial or key pad is output or trim. This is how it all works.
A signal enters the box, the threshold control adjusts the level at which the compressor starts to compress things. It does this based on VOLUME. Always remember that a compressor is doing things in the world of volume, nothing else. When you adjust the threshold you are setting the unit to kick in at a certain volume. Look at this picture of a classic Urei compressor the 1176, the king of guitar compressors.
[The passenger by iggy pop just came on my ipod. Damn is it compressed! Sounds great! ]
The meters measure two things. This is usually what gets people confused. When the compressor is set one way the meter measures the incoming signal. you set this so that the signal hits zero pretty regularly. Then you switch the meter control to change what the meter measures. Now it will show you how much compression is happening. As you turn the threshold knob the volume of the incoming signal crosses the “threshold” of when the unit starts working. That’s why it’s called THRESHOLD. Duh! (if you don’t get it keep rereading this blog. I stared at my first compressor for most of 1979 before the instructions, the nasty comments of a few engineers and logic all came together in a flash of insight)
Once the unit kicks in the meter is showing you how much volume is being squashed. The more the meter moves in this setting the more you are compressing the signal. Once you start to squash the signal it will start to get softer. This is supposed to happen. This is when you use the output/trim knob to turn the volume back up to exactly where it was before. Now you have a signal that is the same apparent volume but the internal dynamics have been crushed together. This is what you are after.
How hard the unit crushes the sound is determined by the ratio switch. This is set at 2 to 1, 3 to 1, 4 to 1 etc. The larger the first number the stronger the effect. Start out at 2 t 1 and work your way up from there. The only other controls on a compressor are attack and release. To explain these I must talk about how compressions SOUNDS.
Once your ear gets used to hearing the compressor doing its magic you should start to hear the unit come on and go off. You will hear this as an unnatural change in the volume. Engineers refer to this as PUMPING. The cheaper the unit the more obvious this effect is. After you get really tuned to it you’ll start to hear it all over everything coming out of your stereo and radio. In fact DJ voices are extremely crushed and compressed and recompressed and limited. This gives them that deep boomy, in your head kind of quality. THIS IS WHAT PROPERLY COMPRESSED SOUND SOUNDS LIKE!
Ever hear Pink Floyd “Dark Side of the Moon”? Slammed, slammed, slammed! “Led Zeppelin? Same thing. Beatles? Jesus the Beatles set the standard for highly compressed music. So if compression creates an effect that you can hear and sounds unnatural why is is used? Because it brings out all the detail of the instruments and voices. Ever wonder how engineers get that cool grainy, crisp sound to lead vocals? Compression. How about the guitar sound that roars out of your speaker? Reverb? Nah! Compression! How about the cymbal sound that seems to shimmer and drift away in long sustain. You guessed it. Do I need to do on? Trust me. This is how pro audio is done.
So let me review how you dial up the voice of god on your compressor.
1. take a signal from a mic, route it into the compressor input. From the compressor output it goes straight to record. Tape, computer whatever it doesn’t matter. Now turn on the unit and listen. Set the meter to measure input. Turn up the input control until the meter is hitting zero regularly.
2. Set the unit to 2 to 1 ratio. Change the meter control so that it now measures compression. Now slowly turn up the threshold until the meter becomes active. The unit is now compressing the signal. You should hear the sound get softer and duller. Get a decent amount of compression happening. At this point it doesn’t sound so great.
3. Adjust attack and release. For the moment you can set both of these to fast. This means the unit will engage really fast and release as quickly. If you are trying to add sustain to a cymbal make the release long. If you are trying to tame a bass that booms sometimes but otherwise sounds cool set the attack to slower so the unit kicks in when the bass gets out of hand.
4. Now turn up the output/trim control until the volume is back where you started. At this point you should have a sound that is the same volume as what you started with but will sound kinda crunched. It will still sound a little dull.
5. Now turn on the EQ on the board. Add a little high frequency. Each kind of compressor sounds a little different. They all remove some high frequency content so you need to add some top back in. In the ideal world you are trying to make the EQ the same as when you started.
If you do this right then the final track will stand out in the mix. It will have lots of detail and life. When I record I compress almost every track. The only tracks I don’t compress are Kick and Snare. Sometimes I compress them as well. Butch Vig, the famous producer of Nirvana and tons of great Sub Pop bands uses gobs and gobs of compression. Especially on the drums. That’s how he gets those drum sounds that leap out at you.
Ok some final, important words about compressors. You may already own a few compressors. Perhaps one of them is a guitar pedal. This is not a compressor it is a paperweight. A box like that is used to add some sustain to your lead guitar sound. It is not a studio compressor. You may own a rack unit with eight compressors in a long unit. You bought it for about 200 on ebay. This is not a studio compressor. It claims it is but this is a bald faced lie. You may own a reverb unit that has a setting called compression. This is not a studio compressor it is a cheap, lousy sounding reverb unit.
When buying studio equipment it is always better to buy less channels of higher quality. The best compressors can cost thousands of dollars for a single unit. This is not overkill.This is quality. It makes a big difference when it comes to compressors. Urei is the most common high quality studio compressor. I like the LA4A myself. They are not cheap, about $500 for a single unit used. DBX makes great compressors as well. These are cheaper and can had for around $300 per channel for a high quality one. I’m partial to the DBX 160. They are really nice on electric guitar. These are many, many others. Some are cheap and some are expensive. It’s up to you what you can afford to spend.
Think of it this way. If you own one high quality compressor for your studio you will use it on EVERY OVERDUB. This means that lots of tracks will benefit from the magic of compression. If you can afford two you are in even better condition. Make sure you buy matching units that have a feature called stereo strapping. This is a feature that allows you to hook the two units together. when you do this one of the units controls operates both units electronics. This allows you to run the outgoing mix (Hey we’re gonna do BUSS COMPRESSION just like the pros) through the two channels. Since the units do the same thing to both channels it gives you a compressed stereo mix without any weirdness from having one side compressed and the other side not compressed or half compressed.
Finally I will talk about limiters. Sometimes these are part of a compressor unit. This is called, oddly, a compressor limiter. A limiter is a compressor that can be set to not allow any signal to exceed a certain limit. When the signal hits the limit the unit kicks in and pushes it back. These kind of use are used by mastering engineers to insure that they can push a mix right up to the limit of their system and it will never jump over the line into distortion. There are uses for limiters in rock recording but they are rare and unusual. I will leave that topic for you to figure out when you’ve mastered compression and mixing…and when you’ve mastered compression and mixing then you are well on your way to Succeeding at Rock.
©Brad Morrison/Billiken Media