A pedal that dampens brighter notes?

I would think a simple graphic eq would do, and just cut everything from about 1.2 kHz up. That shouldn't muddy any of your lower notes at all, and it would take the sizzle off the highs. Boss GEB-7 would do this, and MXR makes a 10-band graphic EQ as well.

 

low-pass filter could help...?

 

The tone knob on the bass, if you have one.

 

For me, I use these two pedals:

A nice Compressor - EBS MultiComp
An expansive pedal EQ - BOSS GEB-7

 

Markbass VLE pedal (don't think it's out yet though!).

 

id say work your eq as previously mentioned, a compressor may help too

 

The Digitech Bass Squeeze is a dual band compressor that I don't like as a compressor, but it can be pretty useful to rceate different tones that are available when you step on the pedal. You can do exactly what you want with it.
Of course, an EQ pedal will do the same and may be more versatile, although it'lllack the compression ability.

I personally use also a very simple setup. Bass goes into a Korg tuner, then into an MXR 10-band EQ pedal, and into a Boss LMB3 limiter. The limiter is there to tame spikes, and I use the EQ to alternate between a bright and a less bright tone. You could have another EQ pedal for another sound, if you wanted to have three sounds available... as long as they're reasonable transparent when switched off.

 

Boss TU-2.

 

+1

 

Electro Harmonix Mole.

 

Birdsong BBox (and there's one in the classifieds).

 

I find the Behringer AD121 to be very useful in taming the highs yet not adding mud.

 

Just thinking about the tone knob thing. A regular tone control is linear, so that it rolls of mids as well as highs. There's a new(ish) product called the Stellatone Tone Styler, a replacement tone knob. It allows you to roll of the highs and retain the important mids so you still cut through. Might be worth a look.

http://www.stellartone.com/Page.asp?NavID=147

The eq charts explain the roll off better than I can in words

http://www.stellartone.com/Page.asp?NavID=164

 

+1

 

Another thought as you say you only use a volume pedal at the moment. There's the fender volume/tone pedal. Rocks back and forth like a regular volume pedal, but the foot plate also tilt/rotates left to right which controls the tone control, similar tone circuit to a guitar tone control.

IIRC this is a reissue of the old D'Armond pedal that Fender now own the rights to.