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Discussion in 'Amps and Cabs [BG]' started by nasaldischarges, Nov 20, 2006.

  1. nasaldischarges


    Jun 11, 2005
    Is Biamping a preamp function? And if so, what are good preamps with biamping capabilities?

    What is crossover, and other crossover related things?
  2. IvanMike

    IvanMike TTRPG enthusiast, Happy, Joyous, & Free. Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    biamping is technically just that, two amplifiers. Now, what is meant 99% of the time is that after the preamp section of the amplifier, an active crossover (external or contained within the head or preamp) will split the signal at a certain frequency (usually adjustable). From there the two signals (highs and lows) are sent their seperate ways to two power amplifiers (generally two in the same "stereo" head or to the two sides or a "stereo" poweramp). After that the two amps send the amplified signals to cabinets that in theory are optimized to those frequencies.

    This works great for PA applications, and many PA systems are triamped or even quadamped with very specialized cabinets for each frequency. In bass amps the cabs are almost never truly optimized for the frequencies sent to them by biamping, and almost always sound "better", "fuller", and louder when run full range. Most amp manufacturers will tell you this when asked, but in the '80s the biamping craze took off and many amps needed to add a crossover in order to be competitive.

  3. +1... biamping was mostly used with bass rigs to compensate for very poorly designed and executed bass cabs 'way back when'. With all the wonderful, full range bass cabs out there that easily reproduce 40 or 50hz to 10Khz+, I don't really see an advantage to biamping... and per above.... there can be significant disadvantages.
  4. nasaldischarges


    Jun 11, 2005
    understood, i was just reading up on biamping and the concept interested me, but i didnt quite comprehend what was going on...

    thanks for the clarifications and advice
  5. I had a BBE 383 preamp with a crossover into a Crest Stereo 900 watt power amp
    I had hopes of using my 2X12 cab for mids and highs and a 15" for the lows
    but they are right when I bridged the amp to MONO the sound was just fine especially if you have a decent EQ section
  6. jady


    Jul 21, 2006
    Modesto, CA
    I wont Bi-amp but i am fascinated by the idea of a dedicated sub cab. maybe a low pass setup at 70-120Hz or so. I have been polluted by my car stereo and now need tumor rupturing bass all the time!!!!
  7. Most people don't get the best out of bi-amping because they don't use it properly.
    If you put a 100 guitar amp side by side with a 100 watt bass amp the guitar amp will blow the bass away, you will need around 300 watts on bass to compete; the same applies to bi-amping, the low mids to highs should be attenuated back and then the overal volume increased to get the true benefits of bi-amping, this priciple works particularly well in the 1x15 + 2x10 configuration where turning the bass up in a full range system could harm the 10s but turning the bass up in a bi-amp setup only affects the 15.
    This site has a more in depth insite into the joys of bi-amping.
  8. watspan


    Nov 25, 2002
    madison, wi

    look at post # 13 for a couple of pics of my biamp rig. Thunderfunk Uncle AMP 420 below. AMP 250 up top into an ampeg pr1528he. I find the flexibility of tone the real benefit as the 420 has an adjustable crossover and timbre setting and you can adjust the eq and volume of the top separately, plus you can use effects in the top end only w/o losing the bass. the pr1528he was designed to biamp, so that may be what helps this work. many posters on the topic feel if you don't have proper cabinets the effort isn't worthwhile. the same cab can be played full range and sounds great--just less tonal flexibility.
  9. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Well, that's PART of it. but a big factor is that hardly anyone has chosen or designed cabs that are especially suitable for it AND bass stage amps, or amps that give more power to the subwoofer section, and a lot of preamps don't allow one to cross over low enough or at a steep enough slope. Or give the option to try the top cab in full-range mode (though with many cab combinations this may cause problems sometimes it's a way to get some extra oomph).

    Really, it's questionable on many stages if that amount of low freqeuncies at high energy is desirable for several reasons (mechanical coupling with stage, interaction with mics), and if there is subwoofer support in the PA, whether another high-energy low frequency source should be around but not in mutual coupling on the same plane as the PA subs because of phase cencellation.

    For solo performers or those working mostly with small PAs though, it can be a great boon to have something that can make equivalent SPL below 100 Hz as their rig can above that. But again, it's hard to find the right set of components that can deal out as well and stay compact too.
  10. I have biamped my rig for a long time. Like watspan mentioned it can be very flexible. The main reason most of us did it is because of the super clean deep sounding lows it provides.

    My first biamp setup was a GK 800RB with a Bagend AF1C (?). The Bagend was a small refrigerator with a horn, 10' and a 18' driver. It weighed in at about 120lbs.

    Next I chose an Alembic F-1X because of the biamp option and paired it was a SWR 2X10 and a 1X18 just to make it more portable.

    Both awesome set ups in my opinion, but like mentioned it's pretty much "old school". I used these through the eighties and nineties. I still have the 2X10 and 1X18, but if I were to start gigging on a regular basis again I am going to get rid of the SWR's and go for a Epifini 4X10. I would also love to here the Schroeder 21012. Both are known for having some real good lows.
  11. nysbob


    Sep 14, 2003
    Cincinnati OH
    Kind of like this, eh? :D


    I used this rig last night. It kicks major ass and neither amp has to even break a sweat. It's overkill for small rooms, but in a big place it rules. No crossover.
  12. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    No active crossover (or at least two inverse graphic EQs), it's not biamping. Biamping sends lows only to one cab (or several), everything BUT lows to the other.
  13. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    God, if I had my hands on that rig... it'd get so rediculously loud i'd probably kill someone. You & John Glascock are the reason i'm now GASing for a vintage SVT, although I'd still use my Sceptre on top.
  14. I use separate cabs for biamping (1x15 + 2x10+horn) with separate level controls then via an Ashdown pre-amp with a variable crosover that goes down as far as 30hz, I don't crossover that low its usualy 100hz (around G string)-120hz from then on the 10s+horn are more than capable.
  15. Beautiful trouble is at my age the mind is willing but the back is weak.
  16. nysbob


    Sep 14, 2003
    Cincinnati OH
    The sceptre would work very well. I had the marshall on less than 2 and it about tore my head off. You have to be very judicious with this stuff unless you think the only person that should be heard in the band is you. :eyebrow:
  17. Isn't it?
  18. cheezewiz

    cheezewiz Supporting Member

    Mar 27, 2002
    Damn Bob...I wish I could have made it down for that gig. I would have loved to have heard that setup!
  19. cheezewiz

    cheezewiz Supporting Member

    Mar 27, 2002

    In this case, it shouldn't be. The guitarist and drummer in Bob's band also smoke!
  20. nysbob


    Sep 14, 2003
    Cincinnati OH
    The guest room is open, pal. Maybe next time.

    when the bears go out next year this rig will rear it's ugly head again. :bassist:

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