bi amping

Discussion in 'Amps and Cabs [BG]' started by bfitz, Jun 2, 2005.

  1. bfitz


    May 18, 2005
    lorain, ohio
    i am starting to try and figure out how to bi-amp (i think that is the right term). i just purchased a boss gt-6b and it has stereo outs on it and i am running it into a g-k backline 350 head into the backline 410 cab, and also into a kustom 250 head into a kustom 2x15 cab. im useing the g-k for more of a bright sound and the kustom for a bassy\midrange sound. this is my first attempt at anything like this and i dont know if i got it semi-right or not. i've heard of pre amps, d.i. boxes, and a few other things of the sort but i really don't know what there all for, or if they aply to bi amping at all. also, i haven't used this setup live yet and was hopeing for any advice on how to mike the cabs, or should i just use the d.i. out on my g-k head. thank you for any advise that you have.
  2. cirwin


    May 2, 2005
    Bi-amping (as the name implies) technically refers to using two power amps, connected to two speaker cabinets, with an active crossover to send low frequency material to one set and high frequency material to the other. Just plugging full-range outputs into two separate amp/speaker combos isn't true bi-amping.

    The purpose of bi-amping is to more efficiently use different sized speakers to reproduce your sound. For instance, having a 15" spkr for low frequencies and 10" spkrs for the higher frequencies. The drawback is more gear and some added complexity. (Stereo power amp, crossover, preamp, two or more speaker cabs.) However some manufacturers are making bass heads that have bi-amp capability built-in. (G-K and Eden among others.)

    Since this seems to be a new field for you, you might want to check around and see if you can find someone who's had some experience with these kinds of set-ups (possibly a PA guys - we always used bi- & tri-amped systems for PA work) and have a chat with them about it.

    Charlie Irwin
  3. BruceWane


    Oct 31, 2002
    Houston, TX
    Biamping simply means using separate amplification for different frequency ranges.

    Typically, a line level full range signal is fed into a crossover, and then the high frequencies are sent to one amplifier and the lows are sent to another. From the amps, the speaker level signals are sent to cabinets appropriate for the frequencies being sent to them. Big woofer boxes for the lows, smaller mid-tweeter cabs for the highs.

    So, a typical biamped bass rig would be laid out like this...

    Preamp > Crossover

    Crossover High Out > smaller power amp > mid-high cab

    Crossover Low Out > larger power amp > low cab

    This setup allows more efficient use of wattage, since reproduction of low frequencies requires a lot more wattage than reproduction of high frequencies.

    With the gear you've got, you can do a sort of "fake" biamp rig by cutting the lows from the GK rig and cutting the highs from the Kustom rig. But since you have two separate control sets to work with, it's going to be a bit harder to come up with a balanced result. You don't want to leave a big frequency gap beyween the highs and lows, and you don't want a whole lot of overlap, either.

    But frankly, you really don't have the gear to effectively biamp. You usually want at least two or three times as much power for the low frequency system as compared to the high frequency system because it takes a lot more power to reproduce the lows. With what you've got, your high frequencies are going to very easily overpower your lows. So I don't think you're going to get much benefit from doing this. It's certainly worth a try, though. Hook it all up and start turning some knobs. You'll probably end up with a lot more frequency overlap than what would truly be considered a biamped system, but if it works for ya, so be it.

    I used to biamp back in the heavy metal/hair band days, but it really doesn't work all that well for a bass rig unless you practice in a really large area or are playing rather large stages. In most situations, the typical practice room or small stage in a bar, you don't have enough distance from your rig for the separate high and low systems to blend back together. It will always sound like highs coming from one point and lows coming from another, rather than one solid sound. Biamping has its place, but unless you're playing arenas, you'll probably find it to be fairly useless.

    Now, if you have no PA support for your gigs, you my need to biamp in order to fill even a somewhat small venue with decent bass. But as long as you've got a PA to do that job, you'll probably want to keep your stage rig a bit simpler.
  4. Yeah, like the guys have already said, you are not really bi-amping, but I actually do the same thing that you are doing with the same equipment,GT6-B stereo'd into two different combo amps...

    My reason is a little different though: Neither of my amps is powerfull enough alone for me to hear myself at practice, so I hook them up together to get a louder and better sound. I run the 100watt rumble as a fullrange amp and the slightly more powerfull (160watt) workingman 15 as a bass bin, cutting everything from 800hz upwards. It works nicely for me at practice, but its a mission to lug this full setup to a gig... I wouldn't recommend it.

    Its not uncommon for people using bi-amps to run say a 410 as a fullrange cab and have say a 15 pushing just low end. I know there is an overlap of frequencies, but it can easily be eq'd out and the smaller speakers actually handle the low frequencies slightly differently to the bigger bin, so they often end up complimenting each other and filling out the low end better, allowing you to run your amp ata slightly lower level
  5. bfitz


    May 18, 2005
    lorain, ohio
    thanks guys, it makes more sence now. i gesse what im really trying to do is get more low end in my sound. the 10's just dont have enough bass to them and it seems like from what you've said that i might be on the right track to getting the sound i want. thanks for the help
  6. abngourmet

    abngourmet Gold Supporting Member

    Nov 11, 2004
    I use an SVT IV Pro, and I "biamp" my rig. I have two Ampeg BXT series cabinets (4X10 and 1X15), and what I do is run the 15 "biamped," that is, run the pre out to the power amp in on the amp, and run the 4X10 "full range," e.g., no pre out but just the out from the amp to the in on the speaker. Is this true biamping as noted above? No. Does it give me more bottom with enough highs to give me the sound I'm looking for? Yes (each cab has an adjustable tweeter). I have a built in crossover on the SVT, so my setup works for me.

    I've tried it in true biamping mode, but like what I'm doing better. Like some have said, play around with what you have, and you'll probably find something you like.

  7. Yeah, it doesn't really matter what you do with your amps/guitars or eq, as long as you get the sound you are looking for without blowing up your amp/cabs...

    it's your sound afterall.