Comment by Benjamin_Dobell | Hacker News Reader

Comment by Benjamin_Dobell | Hacker News Reader

Benjamin_Dobell

This is a long article that starts off stating that mastering is difficult to explain, and then proceeds to not explain mastering.

They're implying that poor mastering was to blame for Metallica's album. Weren't people complaining it was over-compressed? That's mixing not mastering!

Mastering is a matter of making sure that listening to an album from start to finish sounds consistent. That's why songs that go on compilation albums are mastered once on the original album, and again on the compilation - they most certainly aren't mixed again.

Mastering may involve a small amount of compression across all components of the song (although it really shouldn't), but it's mostly controlling loudness, and loudness at different parts of the audio spectrum (more low-end, more high-end). Mastering is effectively something you could do yourself with your stereo's settings (if you were constantly adjusting the settings through-out the song), mixing is fundamentally different and consists of combining "tracks"; vocals, guitar, harmonies, drums, sound effects, adding samples over drums (i.e. mix in a better sounding drum, or hit there-of, over the drumming recorded for the song).

EDIT: For clarity, me stating:

> Mastering may involve a small amount of compression across all components of the song (although it really shouldn't)

is my subjective opinion. Master-bus compression does happen regularly enough during mastering (in addition to during mixing), but as stated, it is typically only a small amount, compared to what a Mixing Engineer can get away with on a per "track" basis.

Compression of individual parts happens during mixing, compression of the entire audio track happens during mastering. (Compression of the master bus sometimes also happens during mixing, but mastering engineers prefer not to work with tracks that have already had heavy compression applied to the master bus.)

The kind of brickwall limiting Metallica's album had, where the volume of the track is maxed out at all times, can only come from compressing the master bus, which is properly a part of mastering, not mixing. (See also: the comically overcompressed mix of Raw Power that resulted when Iggy Pop was allowed to remaster the album himself.)

True, that is what I meant by:

> Mastering may involve a small amount of compression across all components of the song (although it really shouldn't)

Admittedly, I've never listened to the Metallica album in question so I don't know what it sounds like. But I thought that in addition to complaints about loudness and lack of variance (compression), there were lots of complaints about distortion (i.e. clipping) etc. Whilst a mixing engineer could theoretically introduce clipping (by pushing the volume beyond its peak) that would be crazy, they typically just do small amounts of master-bus compression to make it sound louder (as you stated).

But yeah, judging by its reputation that album was messed up by several people along the way ;)

That is the opposite of the truth. A small amount of compression across all components of the song is absolutely a legitimate part of mastering; nearly all records have this.

It's excessive compression and limiting that's the problem. Most of the time this only sucks dynamics out of the record, but in extreme cases (like the Metallica record, or the Stooges record) an inept mastering engineer can introducing clipping to the track.

That's subjective. Just because people do something doesn't mean that I can't say they shouldn't do it. I didn't say it never occurs, I specifically said it may occur.

I'm not against master-bus compression, but as it's fundamentally altering the waveform, dynamics of a song and hence artistic expression, then I personally considering it mixing, even if for some reason Mastering Engineers decide to do it.

EDIT: Man, I just realised how stupid that sounds. "master-bus compression" not considered mastering! Okay, perhaps I need to change that perception... ah, nomenclature.

If the mix engineer does it it's mixing.

If the mastering engineer does it it's mastering.

Either can use bus EQ and bus compression.

The mastering engineer usually approaches the job as a final polish of something that's already finished.

The mix engineer can go back and change the mix after adding bus EQ and/or compression. Usually the mix engineer makes [n, which may be a large number depending on time and budget] of mixes, with feedback from the band and producer and sometimes a record company exec.

Then everyone's favourite mix goes off to the mastering engineer for that final polish, assembly into a consistent-sounding album (if it's an album) followed by final format sourcing.

These days artists often do their own mastering. It's not hard to get something better than cheap mastering, but DIY won't be as good the best full-fat pro mastering.

I was always a fan of the sound of the DBX Quantum processor, which is highly rated by professional mastering engineers - not as highly as custom hardware, but a good few steps up from most DIY mastering options.

> Weren't people complaining it was over-compressed? That's mixing not mastering!

That's not true. Mastering is the process of taking the final output of the master bus and processing it to the final release versions (for the various formats). Depending on where and who does it it can combine many processes: compression, limiting, EQing, stereo widening, bouncing to a tape, etc. It can be a totally functional exercise as well as a creative one.

Something that's over-compressed could have had each instrument on each channel over-compressed (if it was mixed on an SSL for example where there's a compressor per channel), or it could have had far too aggressive master-bus compression. So saying it's definitely mixing not mastering is a stretch.

If you are manually adjusting the volume of the track in response to its level, you are performing compression manually.

The overcompression people complain about in the "loudness war" could have been added at the mixing stage, but is much more likely to have been added at the mastering stage.

Your post led me down the rabbit hole of over-compression, not for the first time, and I ended up at this video which gave a very succinct answer to my question of: "Okay, I realize that music is getting compressed, but what are we losing?"

https://www.youtube.com/watch?v=3Gmex_4hreQ

Via a nice article with analysis: https://musicmachinery.com/2009/03/23/the-loudness-war/

It's a good point that in general we can't know whether the problem lies (solely) with mastering, because we can't know what state the material was in when it was passed along from the mixing engineer.

Legend has it that most of the damage to Death Magnetic was done at the mix stage, not the mastering stage. Master buss compression is absolutely standard practice during mixing. It lends cohesion. Unless you listen to a lot of completely amateur recording, almost all the recorded music you've heard used master buss compression.

On the other hand, it's quite easy for a mix engineer to strap a hard limiter across the buss mix. That's what Metallica did. If the record reaches the mastering engineer with only a couple db of headroom, their hands are tied.

Over compression usually happens at the mastering stage, not mixing.

One of the few exceptions is Rush's Vapor Trails, which was recorded so hot there is clipping on some of the instrument tracks.

Clipping is distortion, not compression.

Clipping is both, really. Most distortion is also compression.

And all compression is distortion.

That's a good explanation of the process and is true in theory/how it should be, but an inexperienced mastering engineer or a clueless band will limit the shit out of a recording. And that could absolutely result in a tinny, over-compressed product. I don't know what happened in Metallica's case, probably failures at different points of the chain.

Reply on news.ycombinator.com