SH Spotlight Compression: the good, the bad, the ugly

Discussion in 'Music Corner' started by Patrick M, Jan 30, 2002.

  1. Patrick M

    Patrick M Subgenius Thread Starter


    Can you help us (non-studio drones) understand compression better?

    As I understand it, you *need* some compression, because you don't want a trumpet solo (for example) way louder than everything else. So it's necessary, correct?

    I get the general idea that compression is like squashing the music -- like my mono Hendrix AYE LP (which I can't stand). Very AM radio.

    BUT compression can also be *good*, right? Like some of the mono Beatles stuff, and Cream.

    So is it too much of a good thing, or what?

    AND, isn't the dynamic range of pop/rock music pretty limited (compared to, e.g., classical), anyway? What's the dynamic range on Slayer's "Reign in Blood"? :)

    I find this all very confusing, and the word "compression" is thrown around on this forum all the time.

    What might be useful is if you could give an example of something with a little compression, then the same thing with a lot. Maybe two examples of the same CD. Or would that violate that "not commenting on other people's work" thing? :p

    Is compression the reason that something like, for example, the Byrds' recordings sound so thin? (I have the SACD, and it's still no great shakes.) The reason that an electric bass sounds nothing like an electric bass, and drums sound nothing like drums? (That is, they are lacking oomph and weight, for lack of better terminology.)

    If it's not compression, then what is the reason that so few rock recordings sound "right" in the bass and drums, in particular?

  2. Steve Hoffman

    Steve Hoffman Your host Your Host

    Well, compression is the most misunderstood technique in the recording process. I could write a book on its uses and misuses.

    Let's see.

    Yes, we need some compression in our music. The sounds of real life won't do for most recordings. There has to be a way to make everything simmer together, like a good Italian sauce. But if you overcook, or overflavor: disaster!

    Easy instruments to record? Well, a guitar amp works as a compressor too. The harder it is hit, the more compressed the sound; nice tube overload. The volume remains constant, no matter how loud it gets. That makes the electric guitar one of the easiest instruments to record. The human voice is one of the hardest. I'm sure you have tried recording your voice into a tape recorder, watching the VU meters go as you do it. If you sing too loud, the tape goes into total distortion. So, you have to turn down your microphone. If you sing too quiet, no one can hear you at all. Our voice has about a 90db or more dynamic range. Your VU meters only have 20 or so db to measure, and most pop records of the 1970's have about 10db dynamic range. So, the voice has to be "limited" when recording, or else the quiet notes will vanish in the music, and the loud notes will overpower everything else. It's tricky to get it just right.

    You wanted a few examples of two different versions of the same song with different compression ratios? OK. Take the case of Pet Sounds. Listen to the mono mix of (let's say) "Wouldn't It Be Nice". A lot of warm tube compression keeps the voices "in the mix", riding along with the music track. Not the best mix on earth, but totally of it's time. Now, listen to the stereo remix of the same song, ignoring the fact that it seems more open because of the stereo effect. Just listen for tonality and mixing style. The voices have a squashed, edgy quality that make them stand out too much. They are overcompressed, and then EQ'd to make them more "transparent". Problem is, they don't flow with the music anymore. They sound like they were recorded in a different time zone then the music....

    Another example. The mono version of "Beatles For Sale". Listen to "Eight Days A Week" on the CD. Now that is overcompressed! The poor limiter has hit the wall and can't compress anymore, so it just distorts. Ouch...Overload! The stereo version of the song was mixed with much less compression, using the famous Fairchild stereo tube limiter (used on all stereo Beatles mixes). This version sounds much better, and it's not just because it's in stereo. Even played back in mono, the stereo version at least breathes a little, and since the limiter is not bottoming out, the song has a nice 10db of dynamic range. Pretty nice for Abbey Road in those days. On the other hand, the mono mix of "Eight Days A Week" has about 2db of dynamic range. Youch! Even the voice on your telephone has about 25db of dynamic range! More than any Beatles mix...

    Now the Byrds recordings sound like that because that is how the engineer and producer wanted them to sound. Mainly EQ choices, with a lot of limiting, especially on Jim's (Roger's) 12 string. That sound can give one a headache after a time, eh?

    Compression is what makes something sound louder, but really, it just removes anything softer. I can whack a snare drum, and the microphone will overload, and the vu meter will pin. Just one snare whack, and the whole recording is ruined. Why? It's really loud and dynamic. But, with compression, it can SEEM loud, but it really won't be. Get it? It's like when you watch TV. The shows seem normal in volume, so you turn up the sound to hear everything clearly, but when the compressed commercial hits, you cover your ears. But, there is a point in the show where the volume actually hits THE SAME dynamic peak as the commercial. It's just that the commercial STAYS AT THAT VOLUME ALL OF THE TIME, whereas the show only hits that peak when a person is yelling or something... See?

    Finally, think of compression visually like this. You are standing on one side of a sliding glass door. Someone is on the other side, and as you watch, starts pushing their face against the glass. The face doesn't get any closer to you, it just starts to look squashed, like a good 90mm camera lens will do. You don't want the person's nose to look really long and unnatural, see? You want the perspective to be "flattened" so it flatters the person's face. Well, same with music.

    Phew. Any questions?

  3. Grant

    Grant In holiday HELL

    United States
    Excellent explaination, Steve.

    The hardest thing to do is to get the compression right to glue everything in it's place.
  4. Richard Feirstein

    Richard Feirstein New Member

    Albany, NY
    Example, I have a wave file of Bob Dylan in Nashville back in the late 60's with a great guitarist on electric guitar playing a short unreleased never finished tune. It sounds so good you would want to demonstrate your state of the art speakers with this sample. On a boot I received the sample was obviously highly compressed, like the typical commercial pop release, and it is lifeless and nothing you would want to play to anyone for the sound alone.

    Steve, I know you go back to the master mix to see what the producer wanted, but back in the good old days, playback speakers were often highly inacurate, and the needs of AM play and vinyl play on cheap players that could not track to save themselves were what often drove the mix. Your job is not easy considering all of the possibilities. One reason the mono of Blond on Blond is full of bass and the Stereo is lacking in bass is likely the result of different speakers being used to do the two different mixes (Bob was involved with the mono mix and not the stereo mix, at two different locations). The latest SACD mix apparently used a later stereo vinyl mix as its model and not the mono mix as its model. All I can say is "good luck". This is more art than science
  5. Beagle

    Beagle Senior Member

    Yes, the Roy Thomas Baker sound, born in the 70's. He explained this was why his stuff sounded louder and "better" over the radio.

    Compression does make sense, in the way Steve so wonderfully and eloquently described. Unfortunately, in todays world it is used for one rock CD to "outmuscle" another on the radio. Hence, unlistenable crap like Stone Temple Pilots 4.
  6. Steve Hoffman

    Steve Hoffman Your host Your Host

    That's right Richard, it's an art, and art can be VERY subjective, eh? But I think I'm pretty good at it by now, and people seem to like what I do! Remember, I'm not a recording engineer by training. I got started doing this back in the 1980's when I was not happy with the actual sound of some albums that I was compiling on paper. When the test pressings came to me, I was shocked at the bad sound. I felt I should step in, for the artists' sake, and I've been doing it ever since.
  7. Richard Feirstein

    Richard Feirstein New Member

    Albany, NY
    If ears could vote they would vote that you are a very good artist. There is an article by an audio engineer on a technical site where he notes that as a kid with a band they put together the greatest hi-fi stereo recording every made. When it was played on the FM radio it sounded like total junk. He learned very quickly that a mix that sounds great on a top of the line stereo system may not sound like much when it gets passed through the typical sound processing applied in excess at the radio station. Getting it to sound great on my stereo and my kids boom box and my AM radio is a great art indeed. Taking those mixed master tapes and making it better is a great way to make a living.
  8. wes

    wes Forum Resident

    Thank god you did.................It takes someone like you who cares about the artists integrity when it was first recorded....Finding the original tape and then researching what the artist intended as far as the recording goes....because that's a big part of the artist's expression at the time...and it should be preserved.....

    It amazes me that some record companies won't bother looking for the correct tapes...........Just find any old tape and put it out on cd/tape without any thought of the artists intentions.........

    Steve, you really are one of my heroes.

  9. wes

    wes Forum Resident

    That message was responding to Steve's post about mastering being an art.

  10. Steve Hoffman

    Steve Hoffman Your host Your Host

    Hey, thanks Wes!!!
  11. Steve Hoffman

    Steve Hoffman Your host Your Host

    Reopened by request.
    George P likes this.
  12. Steve Hoffman

    Steve Hoffman Your host Your Host

    RIP Patrick.
    George P likes this.

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