May 27, 2006 7:35 AM   Subscribe

For the would-be recording buffs: understanding compression. A three-part series which explains the workings and uses of compressors, limiters, expanders, and gates. Plus some thoughts on the modern epidemic of overcompression from the listener's perspective.
posted by ludwig_van (39 comments total) 19 users marked this as a favorite
Hooray! Thanks for this. I remember this came up in an earlier discussion, and I kept meaning to do more research on the subject.
posted by SmileyChewtrain at 7:46 AM on May 27, 2006

The trick about using compressers to increase attack on "mushy" notes is something I didn't know about at all, but makes sense, and will promptly be used. Hooray again!
posted by SmileyChewtrain at 7:52 AM on May 27, 2006

Yeah, I think that's one of the more interesting and less commonly-known uses that he mentions.

Also, I wasn't sure which one to make the main link, but I hope people read the stylus article, too; I thought it was quite good, and it's not just for the technically-inclined. Rmember folks: just say no to overly aggressive limiting!
posted by ludwig_van at 8:06 AM on May 27, 2006

wow. this has always been a glaring hole in my understanding of studio recording. I've tended to just nod my head when my friend would gush over the new compressor unit he'd just picked up.
posted by Busithoth at 8:10 AM on May 27, 2006

Perfect timing. Working on my band's mushy indie album right now. Thanks!
posted by dobie at 8:22 AM on May 27, 2006

Compressors are the piece of gear that take just as much "chops" to use as an instrument.
posted by sourwookie at 8:23 AM on May 27, 2006

From the "listener's" link:
Even The White Stripes, those fashionistas of vintage recording and mixing technology, compress their records massively

I know that Liam Watson, who produced their last couple of albums, is a big fan of Joe Meek. For those who don't know, Meek was a total compression junkie and he'd really over do it sometimes - and that was back in the early sixties.

Getting back on topic, if someone with ears as lo-fi as mine is noticing over-compression then we're really in trouble.
posted by dodgygeezer at 8:27 AM on May 27, 2006

Compressors are so abused these days. CDs were supposed to give us more dynamic range and now we probably have less than Edison got on his cylinders. All you potential recording engineers out there remember to use your compressor for good, not evil.

What happended to dynamic range?
The death of dynamic range
posted by caddis at 8:36 AM on May 27, 2006

Thanks a bunch. Informative but not so long/complicated that my eyes glaze over (i.e. I actually read them).
posted by leecifer at 8:37 AM on May 27, 2006

Good links, caddis. Some of the pictures in the 2nd one are scary!

Hey, so I was going to Ask Metafilter, but since we're all here... does anyone know of a free Windows tool that will output useful statistics on a track, i.e. peak level, number of clipped samples, RMS, etc.?
posted by ludwig_van at 9:14 AM on May 27, 2006

Someone buy me a RNC. Do it now!
posted by cortex at 9:14 AM on May 27, 2006

Thank you, this is great. It's well written, and I really love the visual examples. And the audio ones. I've heard this explained, and I've heard examples, but having it all in one place is a huge help.
posted by ruby.aftermath at 9:15 AM on May 27, 2006

a compression tip for vocal tracks: use multiple compressors. I usually use at least two, one with a quite fast attack and release settings (for the "peaks") and one with slower settings (overall compression). Some people I know use as many as seven at a time. Might be a bit of an overkill there IMHO.

Also try different compressors. They all have different characteristics. My current favourite plug-in-compressor in Waves Renessance. Easy to use and a "warm" sound.
posted by hoskala at 9:37 AM on May 27, 2006

Seven! That sounds pretty crazy. I'd like to see that.

It might be worth mentioning that Blockfish is a pretty neat, freeware VST plugin compressor. It has a highly simplified interface, but it sounds pretty good and is easy to use for demos and what have you. And it has a "complex" mode which turns it into 2 compressors in a chain. I use it with kristal audio engine, which is also free (but Windows only) to make all of my acoustic bedroom recordings.
posted by ludwig_van at 9:42 AM on May 27, 2006

You'll typically have a seperate compressor on every instrument in the track (though more frequently on the bassline and kick), and then compress the entire song again during mastering. So seven isn't excessive at all.
posted by empath at 10:34 AM on May 27, 2006

empath, I know that - I'm pretty certain he was talking about 7 compressors on a single track.
posted by ludwig_van at 10:42 AM on May 27, 2006

Great article, the attack tip is fantastic. I can't wait to try it. Thanks!
posted by cmicali at 11:27 AM on May 27, 2006

Over-compression is the sort of thing that should cause record companies to forfeit their copyrights. Of all the attempted justifications for "piracy", preserving culture for future generations is one that's really strong.
posted by jam_pony at 11:45 AM on May 27, 2006

Thanks for this, ludwig_van. Compression is always something I've stayed away from because it just seems to dissipate the sound more than help it become richer. And that's from a $3500 Manley (a friend had it at his recording studio) to a $75 Art Levelar (that a very nice person gave to us). But with this maybe I can use it to my advantage rather than just leaving the Levelar in the closet until I want to boost some levels. And thanks caddis for your articles as well.
posted by sleepy pete at 12:15 PM on May 27, 2006

Regarding the increased use of compression over the years, besides being used to "out-loud" competitor's tracks, I wonder if it has something to do with an increase in ambient sounds levels of the listeners.

Do we listen to stuff now in more noisy environments? (car, bus, etc)

I wonder because I've started turning on more fans to cool the house down, but the increased white noise has made it hard to listen to movies, with their high dynamic range. To get around the problem, I stuck a compressor inline to squash the dynamic range and making it so I don't have to ride the volume controls to boost dialog scenes only to dial back for the explosions.
posted by todbot at 1:35 PM on May 27, 2006

the increased white noise has made it hard to listen to movies, with their high dynamic range

Not to teach you to suck eggs or nuthin, but most dvd players will compress for you. Sometimes it's called a "night mode."
posted by ROU_Xenophobe at 1:54 PM on May 27, 2006

first time i heard chemical brothers "dig your own hole" i was amazed: the meters on my mixing board were pinned to zero;

we cranked it up, and my ears rang for hours after.

loved it.
posted by fisherKing at 4:22 PM on May 27, 2006

A simple "command line" compressor (and general audio tool) for Linux/Unix heads is the Dyson compressor built into the ecasound audio utility.. good for quickly running over a demo .wav before burning it off to CD, etc
posted by zog at 6:28 PM on May 27, 2006

I saw "COMPRESSION IS FUN" in my live bookmarks and thought for sure it had to be about compressing data or something. What a great surprise! Thanks for posting this.
posted by aceyim at 7:27 PM on May 27, 2006

Most 'rock' I've heard the past few decades has been wall-of-distortioned to death.
posted by HTuttle at 12:25 AM on May 28, 2006

ROU_Xenophobe: I'm actually watching DiVX movies on a Mac mini. I got Audio Hijack Pro and inserted some Audio Unit effects. Compression is the main one, but it's also fun to stick in the big reverb and tube distortion plugins. :)

(and my DVD player is so old to not have such fancy options like 'night mode')
posted by todbot at 1:08 AM on May 28, 2006

Do we listen to stuff now in more noisy environments? (car, bus, etc)
I think it's partly that. But I also think it has something to do with a loss of appreciation for how good music can actually sound. CDs, mp3, crappy earphones, and portable music in general have combined to greatly reduce the music experience for so many. Simply put, people today just don't hear the music. Sadly, I'm not sure too many of them care, either. General appreciation for quality sound has all but died.

Back in the day, even the the lowest-priced audio gear produced good sound. I'd pit my 30+ year-old Pioneer SX-650 (all 35 screaming watts of it) against any of the consumer-grade home audio kits available these days in terms of musical sound. Today's kit excels at two things...volume and bass. (I tend to blame Bose for this trend.)
posted by Thorzdad at 5:51 AM on May 28, 2006

I totally agree Thorzdad, but add to that list PC speakers. As for Bose, their bass is plentiful, but mushy and crappy sounding.
posted by caddis at 8:00 AM on May 28, 2006

Indeed. I know some people who do most of their listening on their laptop speakers, and don't seem to be bothered by the sound. It's like listening to music through a cell phone or something. Blech.

I <3 my Grado SR 60s.
posted by ludwig_van at 8:36 AM on May 28, 2006

Just Say No to overcompression! Great post - thanks.

Perhaps some time with a Reflexe recording of Handel or Taverner would offer some insight to those who have overcompression tendencies. :D
posted by shifafa at 8:48 AM on May 28, 2006

I know some people who do most of their listening on their laptop speakers

Heh. I did a really noisy recording this week, just a one-off two-track in the kitchen. Lots of ambient noise from the street, wife walked in the door during one of the tracks—just ridiculously noisy, especially since the parts I was recording were so quiet. (Super-dark, super-sparse Cat Power-ish cover of Wilco's How To Fight Loneliness. Imagine.)

Played it yesterday for my mother-in-law on her iMac, via the built-in speakers, after explaining how noisy it was. And, of course, you couldn't even tell. Bah!
posted by cortex at 9:06 AM on May 28, 2006

I'm late to the party, and have not much to add, except for:

ludwig_van: great post, thanks. As I've said before, I personally tend to overlook topics such as this one as possible posts, and that's a shame really, considering that this post gets such nice responses.

cortex: please, please, send me that recording. It's a favourite song of mine.
posted by goodnewsfortheinsane at 1:06 PM on May 28, 2006

have at it, my Dutch compadre
posted by cortex at 3:47 PM on May 28, 2006

I thought the ambient sounds added something to it. I believe I heard your wife in the right channel. And it sounded like keyboard and mouse noises at points?

I tried to record some ambient sounds around 3 AM once, and there were cool police sirens and keychains jingling as drunk people walked home, but there was too much wind noise, so it wasn't useable.

The other day I was recording a vocal part, and I hit play, stood up to sing, and smacked my kneecap really hard on my desk. It sounded like this.
posted by ludwig_van at 6:09 PM on May 28, 2006

Fantastic cortex, thanks.

On preview: I thought the ambient sounds added something to it.

Christ ludwig, that was exactly what I was just trying to explain to cortex in a lengthy email!

And as for your fateful episode: as I tend to tell my performers a lot in these situations, Leave. It. In. :)
posted by goodnewsfortheinsane at 6:18 PM on May 28, 2006

One genre in which huge dynamic range is alive and well is hip-hop (which might have contributed to hip-hop's recent ascendance).
posted by Tlogmer at 7:44 PM on May 28, 2006

One genre in which huge dynamic range is alive and well is hip-hop (which might have contributed to hip-hop's recent ascendance).

Really? Any artists or tracks you have in mind? I think of (mainstream) hip-hop as being highly compressed; I've heard it offered that one of the contributing factors to its popularity is actually that hip-hop mixes tend to sound better than rock at similar compression levels.

And the stylus piece seems to allude to this when it says:
Even The White Stripes, those fashionistas of vintage recording and mixing technology, compress their records massively; it’s just not as obvious (or wearing) because there are usually less elements being crammed into the mix in the first place. It's similar with a lot of R&B and hip-hop—minimal music without many compositional elements (a bassline, a drum track, a single synth and a vocal, perhaps) can be compressed to seem much louder than a more densely layered piece of music with more elements, because each ingredient can be made to take up that much more space on the CD itself in terms of raw information/signal.
posted by ludwig_van at 8:05 PM on May 28, 2006

CORTEX - That was awesome! Really, really great. Thanks for sharing. (nicely recorded too)
posted by caddis at 11:27 PM on May 28, 2006

Hip-hop can be hugely compressed and still have great dynamic range, because there's so much space in a typical hip-hop mix. There may even be short intervals of silence or near-silence.

Rock mixes tend to be much more crammed with sound. Electric guitar can be an overpowering instrument, and everything else (bass, drums, vox) tends to get loud to compete with it. All of this inhibits dynamic range.
posted by Artifice_Eternity at 10:44 PM on May 29, 2006 [1 favorite]

« Older Better Living Through Chemistry.   |   ok computer Newer »

This thread has been archived and is closed to new comments