# Questions about live EQ/high pass



## noUser01 (Dec 18, 2013)

I'm trying to improve the live sound of myself and my band and was trying to think of how to EQ things so the guitar leaves more room for the bass, while also giving more clarity to the guitars. Here's what I'm thinking:

I tried a High Pass at about 90Hz for fun (since that's what is usually done when recording) and it was clearer, but there was no punch to the tone and quite a gap in the frequency spectrum between the bass and the guitars. It also really lost the low notes when the whole band was playing together.

My band tunes to Drop Ab, meaning our lowest note is - correct me if I'm wrong - just shy of 52Hz (51.91Hz to be exact). Now I understand that every note has harmonics above the fundemental, but what about below? Is there any reasons I shouldn't cut everything below, say, 40Hz? Isn't it all just useless mud that I could leave to the bass guitar to fill up? 

Now obviously to an extent this depends on how I EQ the note, since the Q of the pedal/multieffects unit I use might suck down some of the 52Hz range if I do it at 40Hz... what about 30Hz? I tried a High Pass at 30Hz just now at medium volume on my main patch by myself. It certainly felt clearer and less muddy. Was it missing something? Yes and no. It still felt thick and powerful, but there was a very subtle something different from it in the low end, but as far as I can tell taking it out just made it clearer, not any less fat.

So I guess this leaves me with this:

1) That "something" I cut in my guitar tone, where does it come from if I'm cutting well below where my guitar range ends? Let alone the frequencies my guitar cab would support decently.
2) Is there any reason not to EQ out anything, say, 10Hz lower than the lowest note any of us have on our respective guitars?
3) How else do you EQ things (for guitar AND bass) live to leave room in the mix and bring out clarity? 

Our guitars are always mid heavy with not a lot of bass to try and leave room for the bass guitar, but it never sounds as good as some other professional bands who just use real amps and little to no outboard gear beyond that. Obviously there's a sound guy helping them out, but even when I was at the sound check for Periphery BEFORE any EQ was done by the sound guy their live sound was still better than my band's, as well as most local bands. Since we don't have a sound guy I'm trying to think of what else can be done to improve our live sound on our end (compression, EQ, etc.) which we have more control over now since both guitarist have flexible digital units now.


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## GunpointMetal (Dec 19, 2013)

Its pretty much the same idea from studio to stage....know where your bass is boosted, cut guitars there, know where the guitars are boosted, trim bass there...the only difference is live you can get away with a little more "overlap", like maybe in studio your guitars are HP'ed at 110 Hz, but live, drop that down to like 90 Hz, and your bass is maybe a little scooped around 1K, so live don't scoop quite as much....I figure that, basically, anything below 100 Hz belongs to the kick/bass and then work it out from there. If you need more "push" from the guitars boost a little in the "upper lows" around 120-200Hz. Depending on your tones and stuff though, there are no "rules" other than knowing what range each instrument is working in.


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## Winspear (Dec 19, 2013)

1) The Q. I don't know the actual math but with a high pass filter working at -6dB/octave, if the cutoff frequency was specifying the point at which the signal is -6dB, you would need to set it at 26hz for 52hz to be entirely unattenuated. Make sense?
2) See above


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## noUser01 (Dec 19, 2013)

EtherealEntity said:


> 1) The Q. I don't know the actual math but with a high pass filter working at -6dB/octave, if the cutoff frequency was specifying the point at which the signal is -6dB, you would need to set it at 26hz for 52hz to be entirely unattenuated. Make sense?
> 2) See above



Yes it does, cheers. 

Gunpoint: Thanks man. I guess the problem is figuring out where the instruments sit currently, and where the best place for them to sit would be in the future. Kick for example is a big one for me, don't know how to leave more room for that without going "Uhhh... okay everyone cut a bit at 50Hz... nope, try 55Hz? ..." Especially because while the guitars and possibly bass will have access to a lot of EQ, the drums are what they are. I can't EQ that kick to get rid of all the junk below 35Hz or cut out some space for the guitars and bass above 100Hz, you know? There's just so much content for the drums that I need to figure out where to fit everything in. Vocals too, since cutting the guitars at 3kHz to help the vocals come through usually takes away a part of my tone that I love, haha.


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## GunpointMetal (Dec 19, 2013)

Well, for the most part, unless you have a real pro system compared to a lot of venues you're not gonna be using a 31-band graphic EQ on everything. When we're setting up tones we're not like "Kick resonates at 48Hz, so everybody scoop that", its more like "Kick gets the majority of the sonic space below 80-100 Hz, so that's where I'm gonna HP my guitars, bass should probably mix in with the kick, but not be the lowest thing, so HP bass at 70-80Hz. I know my amp and guitar put out a lot at 2-3kHz, so I'm gonna give the bass a soft cut around there, and boost it around 700-800Hz where my guitar is a little lighter" So its never exact frequencies to an exact amount, its just leaving room where room is needed and filling space where its empty. if you don't already have one, get a mixer and headphone amp to practice with and mic up your whole rig: guitar, bass, drums, vocals, just like you're doing a gig...you can hear where things clash and how things sit in the phones, but you can also record the mixed output and view it on a spectrum analyzer (software usually) if something is missing or masking other things and you can't figure it out, that way you CAN "see" what is too loud or too quiet and find out which instrument needs to be tweaked.


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## PlumbTheDerps (Dec 19, 2013)

ConnorGilks said:


> I can't EQ that kick to get rid of all the junk below 35Hz



Don't most people toss a HPF at around 40hz for precisely this reason? I could be wrong, but that's my impression.


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## xfkx (Dec 20, 2013)

I'd wager that the primary cut off point at 90 Hz was a good idea. If there was something missing between the guitars and the bass, I'd tinker with the bass tone to fill it up, not the guitar.

Also when it comes to low frequencies, your rehersal space may be "lying" to you a bit, standing waves and all that crap.


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## noUser01 (Dec 21, 2013)

Thanks guys, good info here. I'll try all this out!


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## Djentliman (Dec 21, 2013)

I'm really interested in this. I want to get a better rehearsal sound with no mixer or mics. Maybe talk the guitarist to get some external EQ's to help out.


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## noUser01 (Dec 21, 2013)

Djentliman said:


> I'm really interested in this. I want to get a better rehearsal sound with no mixer or mics. Maybe talk the guitarist to get some external EQ's to help out.



He just picked up a POD HD500, and there seems to be a decent amount of EQ options in there. We don't have a bass player right now though so going and trying to overall our band sound at rehearsal won't mean much, heh. But definitely handy to have!


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## TheWarAgainstTime (Dec 25, 2013)

I watched a Devin Townsend interview where he said he cuts some lows (I'm guessing super low, like 40 or so) and does a little bit of a boost at 60hz to help fill in that "something" without muddying the whole thing up. I tried that when I still had my 31 band eq and it worked wonders! I did a slight cut from everything below 80hz and, boosted 60 and cut a little at 125 and I had a tighter low end with a good amount of punch  

As far as low pass, I'm not sure what would be best, but I usually would cut everything above 12K or so a bit to get rid of the nasty high end fizz of my Rectifier  it worked I guess, but you may have better results working everything out in your full band setting


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## Experimorph (Dec 25, 2013)

EtherealEntity said:


> 1) The Q. I don't know the actual math but with a high pass filter working at -6dB/octave, if the cutoff frequency was specifying the point at which the signal is -6dB, you would need to set it at 26hz for 52hz to be entirely unattenuated.



The frequency tells the point where the EQ is at -3 dB, not -6. I can't recall the math either, so I'm actually of no help here.


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