bass guitar preamp with eq, what bands are best?

garybdmd

Member
2016-01-03 5:13 am
Hi I was going to build a simple bass guitar preamp with eq/tone shaping circuit.

QUESTION 1:
If I can only pick 4 bands, what would be the best in your opinion?
bass mid1 mid2 and treble would be the setup.

QUESTION 2:
Also I have a design I was working on with a single mid range cut, but parametric control. Because my control is a simple transistor gyrator circuit, there is a limited range. The constraints of my simple circuit are such that:
the high mid frequency range is twice that of the low mid frequency range.
i.e. I was thinking the parametric control would go from 250hz to 500hz.
or it could go from 200hz to 400hz, or from 500hz to 1000hz etc. If you could pick one range, what would range do you think would be best?

Thanks everyone for your thoughts
 
I realy like the Ampeg eq for bass. They have a fixed bell shape, but you can select the centre frequency with a switch. I can get a great usable sound from them, in combination with the bass elements, tone settings and drive of the input, in 99% of all cases.



What's best depends on the particular situation, I can't read your mind so try for yourself.
 
Hi I was going to build a simple bass guitar preamp with eq/tone shaping circuit.

QUESTION 1:
If I can only pick 4 bands, what would be the best in your opinion?
bass mid1 mid2 and treble would be the setup.

QUESTION 2:
Also I have a design I was working on with a single mid range cut, but parametric control. Because my control is a simple transistor gyrator circuit, there is a limited range. The constraints of my simple circuit are such that:
the high mid frequency range is twice that of the low mid frequency range.
i.e. I was thinking the parametric control would go from 250hz to 500hz.
or it could go from 200hz to 400hz, or from 500hz to 1000hz etc. If you could pick one range, what would range do you think would be best?

Thanks everyone for your thoughts

Markbass LMIII; (all +/- 16 db) bass - 40, low mid - 360, hi mid - 800, treble - 10k

They also use a couple of shaping filters - one works like a contour and the other a low pass filter.

I owned one, and it was a great sounding amp that I pretty much left all knobs at noon and used the contour control to add a bit of scoop. Sometimes.

If I was on a boomy stage I'd cut the bass a little.

Hope this helps.
 

thoglette

Member
2008-12-20 5:59 am
Markbass LMIII; (all +/- 16 db) bass - 40, low mid - 360, hi mid - 800, treble - 10k

They also use a couple of shaping filters - one works like a contour and the other a low pass filter.
Depending on your speakers I'd be dropping the treble about an octave. At 10K you're talking "air" or "sparkle" rather than "treble".

FWIW the top key on my piano is A7 or 3520Hz. Stuart and Sons have one with a B8 (7902ish). It goes "tink" :)

I'm a big fan of switchable filters...frankly I should just build a bunch of parametrics and be done with it:D
 
You'd be surprised how much "bass" information there is at 10k. Harmonics play a huge role in the tone. I don't know how or why, but this is what it is. Most of these modern bass amps are high passed at around 60Hz. The speakers, with very few exceptions, can't handle real low bass.

That's why many, many bass cabinets have little bitty compression drivers on horns, with a 2nd order 2 way crossover.

Gallien Krueger RB1001 has the following tone controls: Bass +10dB @ 60Hz, Lo-Mid +6dB/-10dB @ 250Hz, Hi-Mid +6dB/-10dB @ 1kHz, and Treble +12/-17dB @ 7kHz

All just suggestions.

Have a blast!
 
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I would be surprised, any info I find says 5k to 7 k ( for 6 string) max. The horns are for the stuff below that that the woofer cant handle, especially the 15"ers. What I find interesting is the lack of hifreq drivers in guitar amps. Most of them have a few 10 or 12 inch drivers, how hi do they go?
 
I would be surprised, any info I find says 5k to 7 k ( for 6 string) max. The horns are for the stuff below that that the woofer cant handle, especially the 15"ers. What I find interesting is the lack of hifreq drivers in guitar amps. Most of them have a few 10 or 12 inch drivers, how hi do they go?

Typical Guitar speaker means a huge peak (9 to 12dB) between 2k5Hz and 3k5Hz (any higher and Musicians HATE it) and then dropping like a brick, at least 24dB/oct :eek: and sometimes even higher.

This is a very good sounding Eminence Legend speaker:

Eminence_LEGEND_1258_(Frequency_response_+_Impedance).png
 
I would be surprised, any info I find says 5k to 7 k ( for 6 string) max. The horns are for the stuff below that that the woofer cant handle, especially the 15"ers. What I find interesting is the lack of hifreq drivers in guitar amps. Most of them have a few 10 or 12 inch drivers, how hi do they go?

I'm not trying to be argumentative, but these are facts -


GK cabs have compression driver tweeters.

Mesa cabs have compression driver tweeters.

Markbass cabs have compression driver tweeters.

Fender cabs have compression driver tweeters.

The list goes on.

There are cabs, like the venerable Ampeg 810, that have no tweeters, but it is now the exception rather than the rule.
 
I'm not trying to be argumentative, but these are facts -


GK cabs have compression driver tweeters.

Mesa cabs have compression driver tweeters.

Markbass cabs have compression driver tweeters.

Fender cabs have compression driver tweeters.

The list goes on.

There are cabs, like the venerable Ampeg 810, that have no tweeters, but it is now the exception rather than the rule.

Just because they have tweeters doesnt mean the bass rig puts out anything above 5k. Thats a fact.
 

thoglette

Member
2008-12-20 5:59 am
Just because they have tweeters doesnt mean the bass rig puts out anything above 5k. Thats a fact.

It depends what you're playing. A slapped upright has plenty of HF which should be making it to the front of house, whereas a fingered walking bass line on a P-bass with flatwounds will have much less.

Maybe none after the mix engineer does her thing. Then again, she's probably pulling most of the bass from the DI, not the cab mike so it's all moot.:D
 
Question 1:


Low Shelf with a 100hz knee.
Low mid with med/low q at 500hz.
High mid with med/low q at 2000hz
High Shelf with a 4khz knee.


Question 2:
Para mid 500-1000hz




If this is for fun...have fun!
If you're looking for a long term solution take a look at solutions like the Empress ParaEQ, Q-Strip, RMI Basswitch, Nordstrand Starlifter, Source Audio EQ, Trickfish, and many others.
 
Question 1:


Low Shelf with a 100hz knee.
Low mid with med/low q at 500hz.
High mid with med/low q at 2000hz
High Shelf with a 4khz knee.


Question 2:
Para mid 500-1000hz




If this is for fun...have fun!
If you're looking for a long term solution take a look at solutions like the Empress ParaEQ, Q-Strip, RMI Basswitch, Nordstrand Starlifter, Source Audio EQ, Trickfish, and many others.

Nice Ernie. Sounds a lot like my Mesa d800+.