• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Making the most of a 31 band EQ

eukatheude

eukatheude

Apr 2, 2012
1,777
339
italy, pordenone
#1
So i got myself a cheap 31 band EQ to stack on top of my rig. I've been experimenting a bit with it during rehearsals, but aside from some nice sounds i haven't been able to use it efficiently. Won't have a chance to test it live in a while, since i just moved here and i'm still working on the repertoire with the two bands i found, but i'd like to be prepared when the time comes. Like how to understand which freqs are conflicting with other instruments, hear myself/be heard well, and so on.
Any tips or links to reading on the matter would be great.
Thanks.
 
#2
This might help ...

main_chart.jpg


EQ2.gif


podcomplex-frequency-overview-chart.gif
 
#6
tip 1?

skip the 31-band on your bass rig :)

sorry, there's not much point, and EQ, especially a cheap EQ, is not "free"; you get tone loss and phase shift from all those individual filters, making it usually not worth using here.

use the graphic on things that need more EQ control, like mains, monitors, maybe acoustic instruments, stuff that the benefit of that much processing is worth the tonal "price".
 
#8
+1 to Walter

The typical use of a 31 band graphic EQ is for room correction/speaker correction in either a P.A. or monitor. I'm guessing that you are inserting it in your EFX loop? You've not stated why you wanted that EQ.

I am of the belief that less filters is better. A 31 band EQ has 31 filters. A parametric EQ has 3 or 4 usually. Shoot, I use a parametric as opposed to graphics @ F.o.H. in all cases if I can. If I can't make it sound good with 3 or 4 filters, it's time to go look at the amps or do it on the channels if it's a bad day..
 
  • Like
Reactions: beardedclam
#9
Many (most?) people use 31-band GEQs for feedback control. If you can, put one on every individual monitor plus the mains. Where multiple wedges or other monitor speakers are on the same monitor mix, put an EQ on each unit, not just 1 on the mix, because each one will be in a different place & may be susceptible to feeding back on different frequencies.

Start with all bands flat (no boost, no cut) & mics open/un-muted. Raise the volume until you start to hear a feedback, then back it off until the feedback goes away.

One at a time, boost each frequency band. If you don't get any feedback, set it back to 0. If you do get some feedback, reduce it below 0 by about the amount above 0 where the feedback started. In other words, if you start feeding back at +6, set it to -6, etc.

Raise the volume on that mix again & repeat the above. Repeat again for each mix. It may sound like a lot to do, especially if you have multiple monitors, stereo mains, etc., but it can actually be done pretty quickly with a little practice.

Avoid boosting if you can help it. Whatever you boost comes out of your headroom. Headroom is the amount of power you have available between your average "program" & clipping. That clip point isn't going to move, & any frequency band you boost will be that much closer to clipping. When you get a high-level peak, there will be nowhere to go.
 
#10
ddhm said:
I am of the belief that less filters is better. A 31 band EQ has 31 filters. A parametric EQ has 3 or 4 usually. Shoot, I use a parametric as opposed to graphics @ F.o.H. in all cases if I can. If I can't make it sound good with 3 or 4 filters, it's time to go look at the amps or do it on the channels if it's a bad day..
Click to expand...
well said!

parametrics are "real" EQs.

even then, a full-on 4-band fully parametric EQ is probably still more complexity than you need on a bass rig. the same principle applies here, if you need that much EQ there's something wrong with the rig.
 
#12
walterw said:
tip 1?

skip the 31-band on your bass rig :)

sorry, there's not much point, and EQ, especially a cheap EQ, is not "free"; you get tone loss and phase shift from all those individual filters, making it usually not worth using here.

use the graphic on things that need more EQ control, like mains, monitors, maybe acoustic instruments, stuff that the benefit of that much processing is worth the tonal "price".
Click to expand...


ddhm said:
+1 to Walter

The typical use of a 31 band graphic EQ is for room correction/speaker correction in either a P.A. or monitor. I'm guessing that you are inserting it in your EFX loop? You've not stated why you wanted that EQ.

I am of the belief that less filters is better. A 31 band EQ has 31 filters. A parametric EQ has 3 or 4 usually. Shoot, I use a parametric as opposed to graphics @ F.o.H. in all cases if I can. If I can't make it sound good with 3 or 4 filters, it's time to go look at the amps or do it on the channels if it's a bad day..
Click to expand...

I understand there must be some "tone suck" and that a para would be better (realised it only after buying the eq), though for what my ears tell me, the tradeoff is acceptable for the tones i'm able to dial in, mostly when using it direct to my audio card. For a while i'll only be using it on the bass (bass > eq > head > cab) since i moved to this city not a while ago and still woodshedding with my new bands. :D


JohnMCA72 said:
Many (most?) people use 31-band GEQs for feedback control. If you can, put one on every individual monitor plus the mains. Where multiple wedges or other monitor speakers are on the same monitor mix, put an EQ on each unit, not just 1 on the mix, because each one will be in a different place & may be susceptible to feeding back on different frequencies.

Start with all bands flat (no boost, no cut) & mics open/un-muted. Raise the volume until you start to hear a feedback, then back it off until the feedback goes away.

One at a time, boost each frequency band. If you don't get any feedback, set it back to 0. If you do get some feedback, reduce it below 0 by about the amount above 0 where the feedback started. In other words, if you start feeding back at +6, set it to -6, etc.

Raise the volume on that mix again & repeat the above. Repeat again for each mix. It may sound like a lot to do, especially if you have multiple monitors, stereo mains, etc., but it can actually be done pretty quickly with a little practice.

Avoid boosting if you can help it. Whatever you boost comes out of your headroom. Headroom is the amount of power you have available between your average "program" & clipping. That clip point isn't going to move, & any frequency band you boost will be that much closer to clipping. When you get a high-level peak, there will be nowhere to go.
Click to expand...

Great info, thanks! I'll be sure to put this in practice when i get the chance.

Zooberwerx said:
Less is more...

A simple 3 band EQ: treble shelving, bass shelving, and parametric mid will deliver the goods 99% of the time.

Riis
Click to expand...

IME 3 controls aren't enough, though i've never owned something with a para mid control.
 
#13
Make the bottom end of your eq. into a high pass filter by cutting everything below 40hz.
If the kick drum is miked, cutting everthing below about 50hz would be good. Attenuating up to 120 or so depending on the venue is helpful to reduce boominess.

Also, cutting everything above 4khz or so will reduce clankiness, depending on your tone.

Going wireless(or use a long cord) so you can go FOH is always helpful in setting up your eq.

Good luck.

PS. once you find a setting you like, take a picture of it for future reference.

I use a slow down program (that has a 31 band eq.) , Song Surgeon Pro, that has a fully functional 4 hour demo. You might want to down load it and practice with it so it may help you hear how each frequency changes the tone of the music. http://www.songsurgeon.com/page/demo_or_trial_versions.html?idev=443
 
#15
eukatheude said:
So i got myself a cheap 31 band EQ to stack on top of my rig. I've been experimenting a bit with it during rehearsals, but aside from some nice sounds i haven't been able to use it efficiently. Won't have a chance to test it live in a while, since i just moved here and i'm still working on the repertoire with the two bands i found, but i'd like to be prepared when the time comes. Like how to understand which freqs are conflicting with other instruments, hear myself/be heard well, and so on.
Any tips or links to reading on the matter would be great.
Thanks.
Click to expand...

When an audio system is installed for fixed installation, the equalization for the system itself is set using an RTA (Real-Time Analyzer) if sound quality is important. This provides the most consistent performance and often, the settings are locked in the menu or the controls are covered, to prevent people from messing with them.

If you aren't running your signal through the PA, fine- get your sound and make it whatever you want but if you DO go through the PA, you'll usually find that the FOH sound won't necessarily be great if you get your sound and then the PA operator EQs it. The chance of conflicts is greater if your rig contributes substantial SPL.

I would recommend not using the EQ for gigs until you get up to speed on using it effectively. WRT hearing yourself/being heard well, you'll need to learn about human hearing, a bit about acoustics and the way they interact. Without understanding these, it's going to be an uphill climb. Download a program like TrueRTA or RoomEQ Wizard for a free RTA- TrueRTA is only one band per octave, so it's a lot less able to show what each band is doing but RoomEQ Wizard will show much finer detail. You can inject the signal using a smart phone, tablet or laptop with an audio cable that has a 1/4" plug. The mic and sound card should be fine for this use.

Now that you have found the effect of boosting the 5-6KHz bands, you need to learn that boosting by 12dB will cause problems- you already hear the distortion, now here's the reason: each time you increase the level of a signal or EQ band by 3dB, you have doubled the energy at that frequency (and nearby frequencies, subject to the Q of the filter). Increasing it by 12dB means that you have doubled it four times- (+3dBx4=12dB), resulting in a boost in energy of 16 times. If you're running at 100W, you have now attempted to force the amp to output a lot more power than is possible and if you do this at lower frequencies, you WILL kill some drivers. This isn't just a possibility, it's a certainty. Boosting also increases noise.
 
#16
1958Bassman said:
If you aren't running your signal through the PA, fine- get your sound and make it whatever you want but if you DO go through the PA, you'll usually find that the FOH sound won't necessarily be great if you get your sound and then the PA operator EQs it. The chance of conflicts is greater if your rig contributes substantial SPL.

I would recommend not using the EQ for gigs until you get up to speed on using it effectively. WRT hearing yourself/being heard well, you'll need to learn about human hearing, a bit about acoustics and the way they interact. Without understanding these, it's going to be an uphill climb. Download a program like TrueRTA or RoomEQ Wizard for a free RTA- TrueRTA is only one band per octave, so it's a lot less able to show what each band is doing but RoomEQ Wizard will show much finer detail. You can inject the signal using a smart phone, tablet or laptop with an audio cable that has a 1/4" plug. The mic and sound card should be fine for this use.
Click to expand...

Thanks for the advice! I don't have a mic ATM, but will probably get one when the need arises. Do you know of any study material that i could use for learning more about acoustics?
Now that you have found the effect of boosting the 5-6KHz bands, you need to learn that boosting by 12dB will cause problems- you already hear the distortion, now here's the reason: each time you increase the level of a signal or EQ band by 3dB, you have doubled the energy at that frequency (and nearby frequencies, subject to the Q of the filter). Increasing it by 12dB means that you have doubled it four times- (+3dBx4=12dB), resulting in a boost in energy of 16 times. If you're running at 100W, you have now attempted to force the amp to output a lot more power than is possible and if you do this at lower frequencies, you WILL kill some drivers. This isn't just a possibility, it's a certainty. Boosting also increases noise.
Click to expand...

I understand that. That little distortion i hear, i would call it desirable. I know it's going to create trouble with lower freqs and won't boost them that way. I also know that boosting will increase noise, but so far it has remained within acceptable levels.
 

Latest posts

Top Bottom
Back