EQ bassics thread

Nope. He nailed it. I do however have a different way of explaining it which seems to work well enough for those new to EQ.

EQ is much simpler if you break it down. Everyone has owned a stereo or walkman that has a basic 3 band EQ that has only got Bass, Mid, and Treble. Lets pretend for a second that's all your amp has got.

I would break your EQ up as follows:-

Anything below 120Hz - Think of these as your Bass knob.
120Hz to 1K - Think of these as your mid knob.
Above 1k - Think of these as your Treble knob.

Once you understand that, you can see that each of the 3 bands can be broken down further into mini-groups of Low, Mid and Upper:-

40 - Low Bass
80 - Mid Bass
120 - Upper bass.

200 - Low Mids
500 - Mid Mids (he he)
1K - Upper Mids.

2K- lower Treble
5K - Mid Treble
8K - High Treble.

And so on. A 31 band EQ just keeps breaking it down as I have above.

It's definitely worth learning to master an graphic EQ. It's a very powerful tool, not only for tone shaping, but for eliminating feedback from your PA, for highlighting the strengths of your equipment, for covering up and areas where your equipment is lacking, and also for gear protection and damanage minimisation.

 

I used to do that with an old Yorkville combo. Ah... those were the days. Just turn it on and crank everything.

 

Definately. Although, I personally use a 3dB boost of graphic EQ at 1.3k in my preamp to help cut through the mix. Just me, though.

 

i found the pic very funny because of the dinousaur guy.

well, back to the topic, im getting a SWR grand prix in some weeks, which have 2 semi parametric mid eq, ill be able to work with my tone a lot more.




ive seen a LOT of people who doesnt know anything about sound, and dont know how "knobs" work.

a funny story: i was playng guitar and a friend of mine was singing, we were tying to write some music. i took of the distortion, rise lows and a little mids in the amp, put the tone control on the guitar to minimun, and use only the neck PUP, so i made the guitar sound as round as posible, and my friend VERY immpressed sayd "WOW YOU TURN YOUR GUITAR NTO A BASS!!!! ITS IMPOSIBBLE!!!"

 

This is an excellent point. I spend a lot of time listening to the tones coming from the other instruments on stage and adjusting my EQ to reflect the overall mix rather than just what sounds good for my instrument solo'd. I used to run sound for other acts on the side, and nothing makes a sound mans job more difficult than an act that has everyone fighting in the same frequency.

For instance I usually like to cut 60 Hz a little and add around 125 Hz or so to keep low end and avoid problems with the kick. This might not give me the absolute best tone but I am of the opinion that the overall mix matters more than just my tone.

 

I often do a similar thing if the PA subs are thumping the lows for me, except I cut 40Hz as well and boost 250 instead of 125. Cuts through beautifully. Just don't try and record like this, it doesn't work.

 

Thanks IvanMike. I have been seaching for years for that more felt than heard feel. All my bandmates keep telling me to turn up. I guess I should have looked up TalkBass sooner.

 

hey guys heres a question. is the bass knob on a guitar amp doing the same frequencys as the bass knob on a bass amp?

 

not likely. the maker sets the frequency to whatever they think sounds best and achieves the tone they are trying for. Some are 30hz, some are 80hz etc etc.

 

Can someone explain "shift,"as in the 4 knobs on my Peavey: Low, Mid, Shift, and High. I kind of feel what it does, but can't quite verbalize it yet. I can't find any info either.

Thanks.

 

For me i find it to cut better in live and while you want that warm, bassy tone i do the following.

1) Set all EQ flat
2) Roll back the tone on the bass
3) Cut the high mid a little and boost the low mid a little

 

I believe that the shift knob on the old Peavey amps changes the frequency of the mid knob (making it semi-parametric.) To hear it's affect, boost the mids all the way up and then sweep the shift knob back and forth while playing.

 

It changes the frequency of the mid control from 200Hz to 2KHz.

Edit: It's early here and I'm slow.

 

Hey guys, this might be a more accurate way to percieve various ranges of the spectrum, and it's divided up into octaves. The way each general band functions is not bass-guitar specific - it's more in keeping with what Sound Reinforcement and Studio people would be thinking, though all this is somewhat flexible and the boundaries don't REALLY exist.

Anyway:

Lower bass: 31 Hz to 62 Hz (and below)
Mid bass: 62 Hz to 125 Hz
Upper bass: 125 Hz to 250 Hz

Lower midrange: 250 Hz to 500 Hz
Mid midrange: 500 Hz to 1K Hz
Upper midrange: 1K Hz to 2K Hz

Lower treble: 2K Hz to 4K Hz
Mid treble: 4K Hz to 8K Hz
Upper treble: 8K Hz to 16K Hz (and above)

 

20
25

31.5--------
40
50
63--------
80
100
125--------
160
200
250--------
315
400
500--------
630
800
1000--------
1250
1600
2000--------
2500
3150
4000--------
5000
6300
8000--------
10,000
12,500
16,000--------

20,000

 

Thanks for that detailed info GB! (again )
There's also more discussion of EQ types and functions on one of my pages here:
http://www.ovnilab.com/articles/eqtypes.shtml
I'm open to input for ways that article could be expanded or improved, too.

 

Nice looking page, as always, Bongo. It doesn't hurt that you added a comment to always check out the manual for any piece of gear ... For those who want to understand more, always be on the google prowl for sites that provide additonal info. Some of it could seem conflicting, but the general principles remain the same. It can aid one in getting familiar and comfortable with the subject, to formulate own own strategy for making it all work.

I'd suggest a links section but so much pro sound info is out there for those who want to dig deeper...

 

If boosting adds the coloring of the EQ, why doesn't cutting? It's using the same components to change the signal, right?

 

The ear tends to percieve cuts - gaps in frequency response - less easily than it notices boosts. This is especially true when you are performing the EQ changes in areas the ear is less sensitive in. Thus, an EQ's "coloration" will also be less obvious, to a point, when cutting. This Equal Loudness Contour graph shows the ear's sensitivity throughout the audio spectrum at various average Sound Pressure Levels:



But I'm largely with you - either a cut or a boost introduces a change in phase. I think someone said only a boost does, but that's not so. That's coloration. Actually EQ used correctly is coloration anyway - it's desirable coloration, then.

The important thing is not to unwittingly introduce more distortion by using a lot of boost. Then you end up using the EQ section like a gain stage which is eventually going to run past its headroom, and also possibly have too hot of a signal for the circuits downstream as well, which will further decrease headroom and introduce additional distortion.

Conversely, a bunch of cutting can weaken the signal and then one runs down into the noise floor. Then the signal-to-noise ratio is compromised. It's best to find a happy medium to get best gear performance. So, it's often better to balance boosts and cuts around an imaginary center line - and that's why EQs have contols to make either possible.

...When you get into outboard rackmount EQ you more often see input gain and output gain just like you would on a good compressor, and that's to best match the EQ unit with upstream and downstream circuitry.

 

I find this useful for EQ/filters understanding: http://lowdownlowdown.com/greenboy/Cab/Bandwidth-Q.pdf