Stereo-Rigging a Bass Guitar for Maximum Overdrive

When I was in my twenties, I played bass for a band called Monday's Child. We cultivated a unique sound, and part of that sound was a good, metallic growl from my bass guitar. The only problem was that through a single-channel amplifier, distortion can sound mushy unless you suck alot of the bottom end out of the tone. As much as I love the smooth purr of distorted bass tone, doing without the bottom-end punch the bass gives to the kick drum is not an option.

Since we were a basic four piece band (that is, sans second guitarist), distortion was one of many bass-player tricks to try and fill in the hole in the music during lead guitar breaks. Distorted tones are also great for playing incredible sounding dual-lead harmonies with the guitarist, and make great ripping bass solos and lead breaks. But we cannot forget that the purpose of any bass instrument is to support the ensemble with fat, punchy bottom end, therefore a good, thick bass tone should never be sacrificed for a crunchy sound.

And that was exactly my problem! The Monday's Child sound was as raw and metallic as it was progressive. Distortion helped get it that way, but my ol' workhorse 200 watt KMD GS200B wasn't good at reproducing that overdriven sound. I loved the amp's clean sound: alot like Tool, Rush or Queensryche. It is punchy and clicky with a monster fat tone I didn't want to sacrifice just for distortion.

My friend Richard gave me an old 100 watt Heathkit guitar amp with 2 12 inch speakers in a separate cabinet. It was old and dilapidated, but it worked. I noticed the cabinet gave guitar tones a nice round midrange, so I starting fooling around with playing a bass through it. This amp had no audible bottom end at all, but did give a really smooth purr when played with a distortion pedal. This gave me an awesome idea: Why not run the Heathkit and the KMD in stereo, with the distortion going through the former and the clean, bright punch routed through the latter!

I found a thick, heavy-duty patch cord and spliced in a 12 inch "pigtail" with a 1/4 inch phone plug. Then, I plugged the actual cord straight into the KMD, while plugging the pigtail into a distortion pedal, the output of which I connected to the old Heathkit. I turned both amps on, and was quite pleased at what I heard. When the volume levels of the amps were set equally, it sounded like 2 basses playing simultaneously! Even with half the power, the Heathkit was every bit as loud as the KMD (I'll explain why later).

Then it came time to sculpt the sound. That was not easy with the Heathkit, since it's "equalizer" were only "Bass" and"Treble" dials (REAL old-school). Thankfully, the Heathkit's natural tone was already mid-heavy, almost to the point of being nasal, so simply turning the "Bright Boost" switch off and the "Bass Boost" switch on. And the KMD delivered a superb sound with plenty of punch and click. I normally play with most of the midrange scooped out of the bass to get that sound anyway, so there wasn't much need for me to tweak the tone on the KMD.

And that was precisely what the doctor ordered! By letting the clean channel handle the extreme lows and highs, and the dirty channel handle only midrange frequencies, the two bass guitar sounds blended together almost seemlessly without stepping all over each other to be heard. After using such a rig successfully for almost ten years, I have learned a few things about bi-amping in stereo for a great distorted bass tone.

Use only heavy-duty, quality shielded cable - Cheap, skinny patch cords will be excessively noisy, especially when you step on the distortion pedal. Also, splicing a pigtail into cheap cords is all but impossible. Even better than splicing, if you have the money, is to buy a stereo splitter, like the Rane SM 26S Stereo Mixer, but even less expensive 2-channel models are available. If you decide to use a stereo splitter, buy one with a built-in amplifier to keep signal strength high and steady.

Use at least 200 watts for the clean signal and 60 watts for the overdrive signal - It takes WAY more power to move low frequencies at high volume than it does for highs. A 100 watt guitar amp can bury a 100 watt bass amp easily! It takes at least 200 watts for the bass to be heard in the average rock band, but for a distorted signal that has no low end, an amplifier doesn't have to work as hard, and therefore doesn't need as much power (Think of the strength needed to play a tuba as opposed to a trumpet).

Guitar amps work great for distorted bass tone - With distortion's tendency to suck the bottom end from the tone anyway, why not get an old 100-watt GUITAR amp to handle it? It won't hurt the amp at all, just so long as you keep all the lows out of it. You can also highlight more guitar-centered frequencies in that channel with a guitar amp as well.

Keep the bottom end out of the distortion amp (and most of the top) - Remember, distortion sounds best when used in the middle frequencies. Keeping the low end out of the mix will not only make a cleaner tone, but won't risk blowing the speakers by forcing them to move as far with as much force. Also, keeping the highs cut way back will keep the unit from shrieking with uncontrollable feedback once the distortion pedal is engaged.

Use the hi-powered bass amp ONLY for lows and highs - This also makes for a punchier, fatter clean sound, since the amp won't have to work as hard reproducing overtones throughout the entire audio spectrum. By pulling almost all of the midrange frequencies out of the clean channel's EQ, more of that precious power can be used to make your 4, 5, or 6-string THUMP!

Match the volume levels of each amp - The goal is to make both amps sound like one amp. You cannot have one stepping all over the other; equalize the volume as best as you can. Then, play something while paying special attention to the different notes. Are the very high notes aurally offensive? then cut back the top bands on the distorted amp. Don't want as much click in the sound? Cut back on the high end of the clean amp. As you go from low notes upward, listen to be sure all the note are well-articulated and of even volume (this is where a compressor/limiter comes in handy!)

I have used this setup with much success on the stage and in the studio. It is the best way I have found to get a fuzzy, saturated bass sound that still has weight and power to it. Remember, this is nothing but a garage-band trick to get good distorted bass sound on a shoestring budget. When you get the money, you can spend thousands on a rig capable of a booming overdriven signal. Actually, whether I win the lottery or not, I like the way these cheap, home-made stereo bass rigs sound, and will continue to experiment with them in the future (if I ever get time!).