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EQ/Compression in live sound

Discussion in 'Live Sound [BG]' started by real guitar man, Apr 13, 2014.

  1. real guitar man

    real guitar man

    Apr 13, 2014

    getting into live sound and I've been looking for some tips on eq and compression but can't really find what I'm looking for.

    i want a some instructions that say what part of the spectrum does what

  2. DannyBob


    Aug 28, 2013
    http://www.ovnilab.com/ for everything compressor related :)

    Oh, and I ALWAYS use compression live, I find it essential or you will just stand out at certain points (in a bad way). Don't really know much for the EQ you need as you haven't specified anything about your band/instrument/venue/genre etc. but I always find boosting the mids makes you cut through the mix well. A small start, but hey-ho
  3. real guitar man

    real guitar man

    Apr 13, 2014
    Thanks dannybob.

    something like,
    80-100Hz will make a kick drum sound better
    100-200hz will make a snare sound better
    is the type of EQ stuff I'm looking for.

    just sort of a rough guide
  4. DannyBob


    Aug 28, 2013
    Ah okay, sorry. I thought you meant you were getting into live playing for bass and needed help with EQing that. I don't know about live sound engineering because I am not very smart
  5. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    The problem is that the frequencies that could possibly make anything sound better or worse will depend entirely on specific cases. How each instrument is tuned, what the room is like, how it all fits together. There is no such thing as a frequency that makes "x" sound better.
    Moosehead1966 likes this.
  6. real guitar man

    real guitar man

    Apr 13, 2014
    Just had a search on the iTunes App Store and found an app called Sound Advice. This app is has the type of information I am looking for. Loads of tips for EQing different instruments for different genres, which should keep me going for a while.
  7. derrico1

    derrico1 Supporting Member

    Apr 12, 2005
    Charlottesville, VA
    bongo is right; there's no magic frequency to turn up for each instrument; but there are parts of the spectrum in which particular qualities of instruments live.

    If, for example, you want the mix to feature a singing clarity in the bass guitar's high mids, you'll make sure that the bass is prominent at ~ 800 Hz. But rather than CRANKING the bass track at ~800 Hz, typically you look to the arrangement to make sure no other instrument with strong 800 Hz content is covering the bass part. Here's a good starting point for thinking about how instrument voice qualities relate to frequency ranges.

    If there is unwanted frequency masking between instruments, decide which voice should be prominent in a particular range. You can reduce frequency masking w/ eq somewhat by *dipping* the offending instrument at 800 Hz. But generally the better solution is to fix the arrangement, so that the voices leave one another space--in frequency and/or in time. (And of course, sometimes you want instruments to blur together in a particular range—that's why it's called mixing.)

    As the easiest to manage first step with eq, experiment with putting a parametric eq's high-pass filter on all the voices in a mix except the kick drum and bass. A high pass filter, or HPF, will allow all frequencies *above* its set point to pass. Most channel voices don't contribute much to the mix below 100-120 Hz, so you can usually clear up the mix's low end—that is, give the kick and bass room to breathe—by high passing everything else.

    Play with setting the HPF for a particular voice. How high can you bring it before it cuts into the essential quality of that channel's voice? Find that point, then ease back the HPF a bit until the instrument voice has its appropriate bottom again. Move to the next channel. Rinse. Repeat.

    You'll notice that for some instrument voices, the bottom floor is a lot higher than for other voices. You'll also notice that for any particular instrument, the mix-appropriate setting for a HPF depends on the song. For studio work, you might change the HPF and other eq settings from bridge to chorus, or within individual lines. But for live work, you'll tend to set HPFs and leave them.

    Once you get a handle on HPFs, you'll notice that the same principle applies to low pass filters. Most voices have a frequency above which they're not contributing anything useful to the mix, but only masking the voices that live in that range. (For guitar amps in a rock band, for example, I'll *usually* have an HPF set no lower than 100-120 Hz, and a LPF set no higher than 6 KHz.)

    Now, between setting the HPFs & LPFs, you've worked out the characteristic range for each voice. Within *that* useful range, eq adjustments will change the character of the voice. Sometimes, you'll want a small boost to bring out some part of that character. More frequently, you'll cut eq in part of an instrument's useful range to create space in the mix for some other instrument voice to speak.
    Ewo likes this.
  8. musicman7722

    musicman7722 Supporting Member

    very nice table thank you
  9. I generally recommend newbies (not meant as an offensive term) try to use as little EQ and compression as possible until they really learn how it affects the sound.

    The longer I do this the less of any of that I actually use, honestly.

    One thing that helped me a lot is playing around with EQ and compression in a DAW. Audacity is free and so are several others. Most all of them have EQ and compressor plugins.

    I always use HPFs. On digital boards I use them on everything. On older analog boards that just have a high pass/low cut button I engage it on everything except kick and bass.

    Good luck and have fun!
    WyreAndWood and frnjplayer like this.
  10. 1. Use EQ and Compression on FOH as a last resort.
    2. Less is always more.
    3. If you think you need to EQ out feedback from FOH,you need to look at other problems first such as speaker and mic placement. Bets are you have
    onstage problems with feedback. Ring out your foldback. Mic placement again.
    5k will be that frequency.
    4. Use hard compression as a limiter,if you need. That's fine.
    5. A spectrum analyser app. will do wonders.
    6. Set your gain stage correctly. This is crucial.

    They're long,but extremely informative -
  11. IMO Worst advice ever....

    firstly a 31band EQ should always (where possible) be on your FOH....this is imperative in respect to EQ-ing the room. the reason you ring out a room is so that each mic has a different characteristic however a room with always accentuate or drop different frequencies based upon how it is designed. therefore certain frequencies will be much hotter than others. when you use an EQ, you should always CUT out those frequencies. and im a believer that you should always cut frequencies and never boost unless absolutely necessary.

    the other thing in saying that 5k is your problem frequency is also stupid. every speaker/manufacturer has different bumps and cuts, for example yorkville speakers hve huge problems at 400k, so you drop that....and in fact a lot of other problem frequencies occur at about 1k-2k..but again that is purely speculatory because every speaker and model have different frequency "anomaly's" if you like.

    the number one rule of PA setups is that your speakers should always be in front of your mics. you do this you should reduce severely feedback problems. this is where the 31band EQ comes in. reduce the problem frequencies, and this should be able to give you more volume with less problems regarding feedback. a spectrum app as suggested will certainly be a great hand in picking out those problem frequencies. and certainly learning how to set your gain stages is important as well, but to say EQ as a last resort is not good advice.
  12. Experts. They're everywhere.
    Go back and read what I said,petal.
    If YOU have to ring out your FOH,YOU have bigger problems than understanding when and how to use an EQ & compressor.
  13. of course... :thumbsup:
  14. I posted this a couple of years back, hopefully it's useful...

    Here's what I've found about bass EQ from experience as a player and a sound engineer, in live and studio situations.

    Subtle changes to your EQ can make a big difference, extreme settings are rarely a good thing.

    Always listen before you look. Sometimes a setting that 'looks wrong' sounds great, and the audience are going to be listening to you, not staring at the knobs on your amp.

    Fitting in with the rest of your band is more important than sounding great on your own. Once you and the guitarist(s) work this out, you're well on the way to becoming a good sounding band.

    Distortion generally (but not always) requires more low end than clean.

    Your amp and the PA will rarely produce the same tone when you play. Adjust accordingly.

    A good sound in the house is more important than a good sound from your cab. Adjust (levels and EQ) accordingly.

    Be nice to your sound engineer. It'll pay off.


    50Hz and below (Sub-Bass):
    not much point in boosting here if you're on 4-string. Cuts here help to reduce woolliness and 'clean up' the sound.

    50Hz-100Hz (Low Bass):
    The kick drum often resides around here, so it's best not to have a boost in your sound that will end up clashing with it for sonic space. That said, boost here for a truly thunderous low B (if your cab can produce it).

    100Hz-150Hz (Bass):
    This is where you boost to get some serious thump. That bass that makes your chest vibrate at loud gigs, and makes all the motown players sound so fat? This is where it is. I rarely cut these frequencies, but YMMV.

    175hz-300Hz (Low Mid):
    IME a lot of passive basses spike a little here, so I often end up cutting. If you play a lot on the lower strings above the octave mark, cuts around here will really help the notes sing and not jump out horribly.

    350Hz-750Hz (Mid):
    A lot of overtones/harmonics sit around here on a bass guitar, my tone sounds a bit sour if I boost here, but again, YMMV.

    800Hz-2kHz (High Mid):
    This is where the clarity lies. Boost here for 'bite' and string rattle. Boosting here will help you 'cut through'. A careful boost somewhere in this range can make or break a distorted tone.

    2.5kHz-5kHz (Treble):
    Boost here for killer slap tones, but also hella string noise when moving your left hand about. Cut here to stop your distortion from walking all over the guitarists.

    5kHz and up (Air):
    Absolutely not needed for live work, most basses/cabs won't even put anything out in in this range anyway.

    Hope that helps! As I said, all this information is entirely from my experience, so YMMV!

    Stradivarius and Dave Curran like this.
  15. Great post, thanks!
  16. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    i'm kinda with wyreandwood here;

    feedback out front means something is placed or gain-staged wrong, and that should be addressed at the source before you start carving hunks out of your overall sound with EQ.

    once that's done though, EQ is still useful, hopefully just to make things sound good as opposed to fixing feedback problems.

    +1 also to "less is more" here; i use parametics instead of graphics so i can tweak with my ears instead of my eyes, attenuating what sounds annoying while leaving the rest alone.

    as for compression, i'm a fan, but never on the whole mix! that just sounds weird, pumping and breathing and ducking everything whenever the singer belts out a big note.

    i like compression on the all-important vocals themselves, so i can keep them smooth while they're riding just on top of the mix where they belong. 4:1 ratio, threshold set to where you get just a few dB of squash with normal singing, seems to do the trick for me.

    the key here is to do whatever it takes to keep that compression out of the monitors! that leads to feedback and blown-out voices.
    Last edited: Apr 29, 2014
    KingRazor likes this.