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Bi-amping...How exactly does this work/get setup?

Discussion in 'Amps and Cabs [BG]' started by Angus, Oct 12, 2000.

  1. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    Would someone be able to fill me in? Joris? PBG? Any other capable being? Im getting my Ampeg SVT-4 Pro and the two SWR Goliath 4x10s Saturday, and plan to bi-amp them, to get maximum power out of the head. How does this work? This i should know? How is it setup? How many cords (and of what kind? I would think the heavy speaker cables, but thought id check) See, i know i SOUND like a moron, but im trying to be as careful as possible here! Could someone please fill me in with as much as possible? Pweez? :) Thanks guys!
  2. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    Just setting email notification. Never works if i do it when editting.
  3. Brad Johnson

    Brad Johnson SUSPENDED Supporting Member

    Mar 8, 2000
    Gaithersburg, Md
    DR Strings
    MA, while I'm not intimately familiar with the SVT-4 Pro, what you'll probably be doing is running a cab on each side of the amp,
    full range. The 4-Pro has a crossover but are you thinking of running the lows through one Goliath and the highs through the other? That's usually what people refer to when speaking of biamping.

    For full range, you'll need one instrument cable and two heavy speaker cables, thats it.
  4. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Yeah, I think you'll either want to run stereo full range, like Brad said, where you just run one cab off each side of the amp, or you could bridge the amp (if it can be bridged) and run both speakers in parallel from a mono output.

    As Brad indicated, bi-amping involves putting a frequency crossover between the channels, and running the low frequencies through one cab, and everything else through another. Since both of your cabs are identical,
    I don't think bi-amping is going to give you the best sound. Full range (either stereo or bridged) will probably sound best/loudest.
  5. This is probably how it will work: On the back of the amp, you'll have two sets of 1/4" outputs, one set for each power amp inside the head. Lets call them channel one and two. You'll probably also have a switch somewhere that is labeled bi-amp/full-range. You should also have a frequency crossover knob on the amp somewhere. Plug one cabinet into channel one, and plug the other into channel two. If you choose the bi-amp option, everything below the cutoff point you chose on the crossover will go into one cabinet, and everything above the crossover point will go into the other. If you choose full range, you will get the same signal sent to both cabinets.

    Since you are using two 4x10 cabinets, bi-amping does not make sense. I have a bi-amp head, but use a 1x15 and a 2x10. In my situation, the bi-amp option sounds much better than the full range. Everything below 500 hz goes to the 1x15, and everything above 500 hz goes to the 2x10. This keeps the 2x10 from having to try to reproduce lower frequencies.

    I know the SVT IV has an option where you can bi-amp off of a single SpeakOn output. You have to have a special cord (which SLM sells but you can make yourself) that consists of one SpeakOn connector and two pieces of 1/4" cable.

    I hope this clears everything up for you.

    [Edited by Matthew West on 10-13-2000 at 08:01 AM]
  6. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    Ok, gotcha. Screw that. Well, at least i know exactly how this works now, because i might get a Big Bertha or Big Ben and a Goliath. But if i get the double Goliath, no bi-amping. Thanks guys!
  7. Even if you do get the two goliaths, you can still run in full range stereo mode and utilize both power amps. Either way, you should be fine.
  8. Phat Ham

    Phat Ham

    Feb 13, 2000
    Why is everyone saying that bi-amping is useless with two identical cabs? Bi-amping involves using different amps for different frequency ranges, so you can get different sound bi-amping than playing full range. One amp only has to handle the low frequencies, while the other only has to handle the higher frequencies. This gives each amp more headroom and makes the whole setup sound different.

    So when you get your SVT-4 and your SWR cabs just experiment with different setups and see what you like best.
  9. I.'.I.'.Nakoa

    I.'.I.'.Nakoa Guest

    Aug 10, 2000
    Fort Worth.
    bi amping.. isnt it using both sides of the head for 2 cabs? and pushing all your power? i dunno
  10. MikeyD


    Sep 9, 2000
    No, it will result in *less* headroom because if you have both sides amplifying everything, you can get a lot more power. In my experience, bi-amping (splitting frequencies at the power amp) does not make a lot of sense for bass, because a bass does not tend to generate a wide spectrum of frequencies at high power levels (unlike general P.A. applications). Most of the energy of the signal is at the fundamental (and perhaps the first harmonic). Probably the best bi-amp set-up would be an amp that has, say 400 watts into a "subwoofer" to handle everything below maybe 100 Hz., and a 100 watt side going to a 10-inch or 8-inch driver set (with horn) to handle everything else. The SVT 4 has two equal amp sides, so while bi-amping, one side will usually have to work much harder than the other on any given note. If the amp is run full-range, on the other hand, both sides give the note all they've got. If the speakers are identical, it makes running full-range even more practical.

    When I ran out of power in my bi-amped Carvin stack (with different speakers), I found that it pounded out a lot more volume when I ran it full range, which supports my point: more headroom in full-range mode.
    - Mike
  11. Brad Johnson

    Brad Johnson SUSPENDED Supporting Member

    Mar 8, 2000
    Gaithersburg, Md
    DR Strings
    I didn't say it was useless. The idea behind biamping is seperate amplification for different frequency ranges, typically to cabinets that better handle that range. Send the lows to cabinets that have an easier time reproducing lows, like a 15 or an 18 (or any cabinet designed to produce lows), send the mids and highs to a cab that may have a hard time reproducing lows. Neither cabinet has to work as hard trying to reproduce the full range of sound in this example. There are a few ways to biamp.

    The kicker in MA's example is, he's using identical cabinets that are usually run fullrange because, like the Eden XLTs, they produce the full range of the basses sound. If they were weak at producing bass, two of them would not be an optimal choice for a biamp rig, maybe one Goliath with a 15 or 18.

    IME I've biamped and triamped and what works best for me is...full range. If MA wants to try it:

    Run one side of the crossover (low frequency out)into one side of the amp. Run the other side of the crossover(high frequency out)into the other side. Connect a speaker that you want producing lows only to the first side... mids and highs to the other side. Set the crossover frequency and see what you think.

    One of the inherent problems with biamping with a single point crossover is creating a hole on the sound at the crossover point because of the cutoff. A way around this is to have a crossover for both low and hi pass, that way you can overlap the frequencies and maintain a natural sound.

    Hope that helps.
  12. The system that I use was sugested in the Peavey publication for bass I think its The Low Down. I run full range three way cabinets that are down 10 db at 40 cycles and even more at 30 cycles where the B string lives. When I need a large rich sound I add a powered 1-18" cabinet crossed over at about 60 to 80 cycles this adds a lot of depth. The full range cabinets are not crossed over and go through the effects. the eighteen comes from the crossover and has no effects.
  13. Brad Johnson

    Brad Johnson SUSPENDED Supporting Member

    Mar 8, 2000
    Gaithersburg, Md
    DR Strings
    That ain't no "coffee shop" rig, bassdude :D

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