True RMS limiter/comp recommendations?

Author
Post
Essentials Only Full Version
JazzSinger
Max Output Level: -73 dBFS
  • Total Posts : 895
  • Joined: 2004/07/06 16:30:59
  • Status: offline
2013/01/25 21:31:31 (permalink)

True RMS limiter/comp recommendations?

I am looking for a compressor/limiter that responds to the power (true RMS, NOT the averaged peak level) of a signal.
 
Quick explanation: A signal with lots of harmonics sounds louder to the ear than a sine wave of the same height. This is because all the harmonics combine to produce more power. This is true RMS. Peak average is only RMS for pure sine waves.
 
It doesn't even have to be a real-time VST plug. A stand-alone program would do.
 
Is there even such a thing? I can't find one., and I've really searched.
Surely computers are ideal for fourier analysis and perfect for this kind of limiter?
#1

15 Replies Related Threads
    ltb
    Max Output Level: -48 dBFS
    • Total Posts : 2707
    • Joined: 2005/06/19 13:34:08
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/25 21:47:20 (permalink)
    IIRC Waves C1 &  Renn collection responds to rms & peak using ARC (auto release control)
    #2
    guitardood
    Max Output Level: -82 dBFS
    • Total Posts : 413
    • Joined: 2004/08/02 21:12:50
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/25 21:48:52 (permalink)
    If I'm not mistaken, the UAD Precision Limiter has this capability and does a nice job of boosting RMS without crushing harmonics too much.  Although you need a UAD card to use it.   It's on the master bus of every one of my mixes.

    Best,
    guitardood

    #3
    John
    Forum Host
    • Total Posts : 30467
    • Joined: 2003/11/06 11:53:17
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/25 22:05:26 (permalink)
    RMS is an average. Root Mean Squared. Harmonics shouldn't play much of a role in most material. They are weak in most cases in comparison to the fundamental frequencies. Pianos are one of the few instruments where this is not the case for the lower notes.  

    You may want the leveling PC2A or the new one because its not a peak compressor.  Limiting is meant to avoid having the signal go beyond a set dB.  It can cut off the peals and control the RMS level. But by doing that you get rid of the dynamics in a signal which causes ear fatigue. The song becomes less listenable.  A little limiting wont harm most music and is important to ensure no clipping. 

    Best
    John
    #4
    guitardood
    Max Output Level: -82 dBFS
    • Total Posts : 413
    • Joined: 2004/08/02 21:12:50
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/25 22:14:02 (permalink)
    John
     Harmonics shouldn't play much of a role in most material.


    Should have said 'transient peaks', sorry.


    Best,
    guitardood

    #5
    John
    Forum Host
    • Total Posts : 30467
    • Joined: 2003/11/06 11:53:17
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/25 22:24:04 (permalink)
    guitardood


    John
    Harmonics shouldn't play much of a role in most material.


    Should have said 'transient peaks', sorry.


    Best,
    guitardood

    Sorry, that wasn't aimed at your post I wrote that to the OP only. It just took me longer to write than it should. 

    Best
    John
    #6
    JazzSinger
    Max Output Level: -73 dBFS
    • Total Posts : 895
    • Joined: 2004/07/06 16:30:59
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 07:15:32 (permalink)
    guitardood


    If I'm not mistaken, the UAD Precision Limiter has this capability and does a nice job of boosting RMS without crushing harmonics too much.  Although you need a UAD card to use it.   It's on the master bus of every one of my mixes.

    Best,
    guitardood
     
    Thank you for your reply.
    I've had a look - it seems the RMS they are talking about only refers to one of the available metering modes.
     
    There is no further explanatory material unfortunately.
     
    This seems to be a problem with most VST plugs. Claims couched in marketing terms, but nothing useful to help a technician know what it really does.
     
    #7
    JazzSinger
    Max Output Level: -73 dBFS
    • Total Posts : 895
    • Joined: 2004/07/06 16:30:59
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 08:10:57 (permalink)
    carl


    IIRC Waves C1 &  Renn collection responds to rms & peak using ARC (auto release control)

    I cannot find the term "auto release control" nor RMS anywhere in the C1 manual.
     
    Having said that, I must say the manual from Waves is exemplary. Comprehensive, well explained, excellent.
     
    Renn collection seems to be gone from the Waves site, although I find it talked about in forums.
    #8
    clintmartin
    Max Output Level: -36.5 dBFS
    • Total Posts : 3893
    • Joined: 2009/10/11 12:16:43
    • Location: Fort Smith, AR
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 09:39:52 (permalink)
    http://www.tokyodawn.net/tokyo-dawn-labs/

    These TDR feedback compressors work good. The blue one is still in beta and uses a lot of cpu. They don't have a limiter.

    Cakewalk, Harrison Mixbus 4, Waveform 9, ADK intel i7 2600 3.40 ghz, 8gb Ram, Win 7, Presonus Audiobox 44VSL. 
    http://www.youtube.com/c/clintmartinmusic
    https://itunes.apple.com/...lint-martin/1010966023
    https://open.spotify.com/artist/4x4TBz32i56bTJkgu7b4tN
     
     
     
    #9
    CJaysMusic
    Max Output Level: 0 dBFS
    • Total Posts : 30423
    • Joined: 2006/10/28 01:51:41
    • Location: Miami - Fort Lauderdale - Davie
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 10:53:17 (permalink)
    I have 2 words to say....   FAB Filter

    www.audio-mastering-mixing.com - A Professional Worldwide Audio Mixing & Mastering Studio, Providing Online And Attended Sessions. We also do TV commercials, Radio spots & spoken word books
    Audio Blog
    #10
    bitflipper
    01100010 01101001 01110100 01100110 01101100 01101
    • Total Posts : 26036
    • Joined: 2006/09/17 11:23:23
    • Location: Everett, WA USA
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 11:44:31 (permalink)
    Processors that detect RMS do in fact calculate "true" RMS, which takes into account the contribution of harmonics. RMS for a complex waveform is, by definition, the sum of the RMS values of each harmonic. 

    reaComp comes to mind as one compressor with RMS detection, and features a variable RMS window. The free TDR Feeback Compressor also uses RMS detection, IIRC, as does Stillwell's Bombardier. Ozone's multiband compressor is switchable between peak and RMS. 

    But my favorite compressor - for everything - is FabFilter's Pro-C. It's not obvious looking at it, but it does feature an RMS-detecting mode; they just label it "classic style".

    EDIT: just thought of another one with switchable peak/rms detection - Klanghelm's DC8C. It's cheap and has about every bell 'n whistle you could want, including a unique S-shaped release curve that's supposed to help make it more transparent.

    post edited by bitflipper - 2013/01/26 12:16:41


    All else is in doubt, so this is the truth I cling to. 

    My Stuff
    #11
    The Maillard Reaction
    Max Output Level: 0 dBFS
    • Total Posts : 31918
    • Joined: 2004/07/09 20:02:20
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 12:24:35 (permalink)


    Hi Dave,

    Peaks are more or less instantaneous.

    It seems like as soon as you introduce RMS detection that there must be some sort of duration defined with which to esteem an average over.

    So, how does that work in practice? Are these compressors look ahead? Do they look behind and anticipate (perhaps with a slow attack potential)? Do they run more effectively as offline processes?

    Thanks for any info you can share.


    best regards,
    mike


    #12
    Jeff Evans
    Max Output Level: -24 dBFS
    • Total Posts : 5139
    • Joined: 2009/04/13 18:20:16
    • Location: Ballarat, Australia
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 15:10:34 (permalink)
    It is a good question as I am sure many have wondered what the difference is especially if a compressor provides both modes of operation.

    http://www.uaudio.com/web...uly/text/content2.html

    http://www.doctorproaudio...s-compressors_en.shtml

    http://www.izotope.com/su...multiband_dynamics.htm

    Specs i5-2500K 3.5 Ghz - 8 Gb RAM - Win 7 64 bit - ATI Radeon HD6900 Series - RME PCI HDSP9632 - Steinberg Midex 8 Midi interface - Faderport 8- Studio One V4 - iMac 2.5Ghz Core i5 - Sierra 10.12.6 - Focusrite Clarett thunderbolt interface 
     
    Poor minds talk about people, average minds talk about events, great minds talk about ideas -Eleanor Roosevelt
    #13
    bitflipper
    01100010 01101001 01110100 01100110 01101100 01101
    • Total Posts : 26036
    • Joined: 2006/09/17 11:23:23
    • Location: Everett, WA USA
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 15:30:20 (permalink)
    Yes, Mike, RMS detection implies a time delay equal to the RMS window, typically 50ms. That would be considered a medium attack for a peak-sensing compressor, but imposes the minimum attack time for an RMS-sensing compressor.

    You cannot achieve a fast response with RMS detection, and large peaks can and do sneak past. This could be mitigated with lookahead, which Pro-C does not have, and I don't know offhand of any compressors (except limiters) that do. But RMS-based compression is used for volume leveling, not peak limiting, and so is usually preceded by a peak-sensing compressor to shave off peaks before the signal gets to the leveler.


    All else is in doubt, so this is the truth I cling to. 

    My Stuff
    #14
    The Maillard Reaction
    Max Output Level: 0 dBFS
    • Total Posts : 31918
    • Joined: 2004/07/09 20:02:20
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 15:34:04 (permalink)


    Thanks!!!


    :-)


    #15
    SuperG
    Max Output Level: -63 dBFS
    • Total Posts : 1371
    • Joined: 2012/10/19 16:09:18
    • Location: Edgewood, NM
    • Status: offline
    Re:True RMS limiter/comp recommendations? 2013/01/26 17:52:04 (permalink)
    bitflipper


    Yes, Mike, RMS detection implies a time delay equal to the RMS window, typically 50ms. That would be considered a medium attack for a peak-sensing compressor, but imposes the minimum attack time for an RMS-sensing compressor.

    You cannot achieve a fast response with RMS detection, and large peaks can and do sneak past. This could be mitigated with lookahead, which Pro-C does not have, and I don't know offhand of any compressors (except limiters) that do. But RMS-based compression is used for volume leveling, not peak limiting, and so is usually preceded by a peak-sensing compressor to shave off peaks before the signal gets to the leveler.

    Spot on reply. There are tons of compressors out there and many of them allow switching between peak and RMS detection.

    laudem Deo
    #16
    Jump to:
    © 2025 APG vNext Commercial Version 5.1