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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: MakersMarc on September 23, 2018, 07:00:08 PM

Title: To compress (nonlossy) or not to compress?
Post by: MakersMarc on September 23, 2018, 07:00:08 PM
Seems not to benefit really good raw recording but for “B” tapes seems to tighten things up. Any thoughts? For most shows I’m 😈 and running my 620 at -15 which results in levels around -12. So I need to amplify and also compress? In what order?

Thanks!
Title: Re: To compress (nonlossy) or not to compress?
Post by: Gordon on September 23, 2018, 09:26:14 PM
Do you mean compress crowd noise between tracks? If so volume envelope works great when needed. Then bump overall gain.
Title: Re: To compress (nonlossy) or not to compress?
Post by: nulldogmas on September 24, 2018, 07:42:41 AM
I usually normalize the raw file, then visually eyeball the waveform to see if there are stray bits of applause or occasional drum hits that are preventing the file from normalizing to a decent overall level, and then compress (or envelope or what have you) to account for those.

Even more quick and dirty rule: If, after initial normalizing, there's at least one song that's consistently clearing -6dB, then don't touch it, you're done.
Title: Re: To compress (nonlossy) or not to compress?
Post by: Gutbucket on September 24, 2018, 11:23:25 AM
Board is acting strange. I wrote a post, but get a message which reads:

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Title: Re: To compress (nonlossy) or not to compress?
Post by: Gutbucket on September 24, 2018, 11:29:13 AM
trying again..

Seems not to benefit really good raw recording but for “B” tapes seems to tighten things up. Any thoughts? For most shows I’m 😈 and running my 620 at -15 which results in levels around -12. So I need to amplify and also compress? In what order?

Thanks!

I take this as asking about management of overall dynamics rather than just taking care of stray peaks doing normalization.  If so, my answer is "it depends".  If I've got mics on stage close to the sources I often need to do some compression to get the live on-stage dynamics down to something reasonable and reproducible without having to constantly adjust the volume knob, otherwise if I turn it down enough I loose details and can't hear the quiet parts.

But from a more distant AUD location there is less of a need as the dynamics are nowhere near as great out there.

Similar thing with PA amplified stuff. It already has compression and limiting applied, sometimes lots of it.  Sometimes a touch more overall compression helps, sometimes not, but the musical content is always more compressed to start with (even though the overall dynamics between the quiet parts between songs and the songs themselves may have a larger difference in dynamics)


You can raise level and/or compress in either order.  Since most any compressor will have a make-up-gain control, you can do both as a single step.
Title: Re: To compress (nonlossy) or not to compress?
Post by: MakersMarc on September 24, 2018, 12:33:50 PM
Hugely helpful thanks Gutbucket sorry I didnt make that clear, yes I was asking about compression of the whole show. For screams I’ll sometimes use the limiter in audacity to reduce them.

Title: Re: To compress (nonlossy) or not to compress?
Post by: Sloan Simpson on September 24, 2018, 01:51:29 PM
I will try adding compression on every recording, and turn it back off if it's not needed (or sounds worse). For this stuff, usually a low ratio and slow attack is best. If you can use a compressor with a sidechain filter, that can prevent bassy tapes from making the compressor pump (a sidechain filter cuts lows -only- on the copy of the signal used for level detection; bass isn't reduced in your output signal, it's merely ignored when triggering compression).
Title: Re: To compress (nonlossy) or not to compress?
Post by: morst on September 25, 2018, 01:30:25 AM

A sidechain will cause the compressor to trigger on whatever the key signal is. For instance, if you EQ your side chain feed to be really bass heavy, it will trigger the comp on bass heavy material. If you boost 2kHz on the side chain feed, then it will compress the signal more whenever 2kHz is loud.


Also, in my experience, Lossless vs Lossy is not usually used to describe the results of dynamic processing. MP3 is an example of "lossy" compression, as it's single-ended and can't be reversed. FLAC and SHN are lossless because they are 100% reversible, and suitable for archival storage, and compact data transfer.

I will try adding compression on every recording, and turn it back off if it's not needed (or sounds worse). For this stuff, usually a low ratio and slow attack is best. If you can use a compressor with a sidechain filter, that can prevent bassy tapes from making the compressor pump (a sidechain filter cuts lows -only- on the copy of the signal used for level detection; bass isn't reduced in your output signal, it's merely ignored when triggering compression).