Discussion in 'Amps and Cabs [BG]' started by Introvox, May 22, 2001.

  1. Introvox


    May 21, 2001
    Ontario, Canada
    I have a Peavey Mark 4 head and a Peavey 1820 Cab w/1-18" and 2-10"...I want to try bi-amping...any advice....I will be picking up an old Crown 300 watt tube amp...should I use the tube for lows or highs?
  2. In the past I used to biamp a Peavey Mk V111. I preferred using the external poweramp for the lows. The Mk V111 had a frequency control for the internal crossover so some experimentation was necessary to get the right result. It depends alot on what cabs you've got, so it's not possible to say what the "correct" crossover point is.

    Has the Mk 4 got a crossover built in? If not you'll need one..

    If it has got a crossover, just try both ways and see what sounds best...

    You say your cab is a 1x18 and 2x10. Can it take two inputs, one to the 18 and one to the 10s? If not you'll need another cab.
  3. Introvox


    May 21, 2001
    Ontario, Canada
    Thanks for the info bud,

    yes the MK4 has a biult in crossover, and the cab has biamp inputs (highs & lows)
  4. Introvox-

    At one point I had the exact amp setup you have now. I played a show at a large auditorium once with another band opening for us. The other bass player had a Sunn power amp and we decided to combine our setups and biamp them. We used the Mark IV for the highs and the Sunn for the lows and it sounded great. After that, I upgraded to a Peavey MegaBass amp that had a biamp option within the one amp and that ended up being a big improvement as well. :)
  5. Alright now. I keep seeing these threads that mention biamping. I'm assuming that biamping is seperating the high and low ends between two different amplifiers (is that correct?). What is the benefit of doing this? Clearer sound? (I have never had the opportunity to try a biamp setup). And lastly, at the lower end of the spectrum, what would one expect to pay to set up a biamp system? I just want to get a general idea where the price range starts at.
  6. Hategear

    Hategear Workin' hard at hardly workin'.

    Apr 6, 2001
    Appleton, Swissconsin
    Aaaaaaarrrrrrrgh (shakes his fist at screen)! When I was asking about bi-amping, you peeps told me bi-amping was silly. Damn you -- damn you all-l-l-l-l-l-l-l-l-l-l-l-l-....
  7. Bi-amping allows for cleaner separation of lows and high.

    I am just starting it now for this very reason. My particular situation involves 15" bass drivers that are very power hungry but have fabulous low end response. They are true subwoofers and have zilch for response above 200 Hz. I use a pair of 6" mid-bass drivers to handle the range from 200 to 6,000 Hz.

    Bi-amping allows you to use an active crossover at the low power preamp stage rather than a passive crossover at the high power speaker stage. I bought a Rane MX22 active crossover for the same amount it would have cost me to build a pair of 4th order passive crossovers capable of handling high power.

    Unlike the passive crossover at the speakers, the active crossover does *not* have the impedance and phasing issues. Another benefit is being able to vary the crossover frequency by twisting a knob. An L/C passive network is both fixed frequency and designed for a specifc speaker impedance. Change the speaker, screw up the crossover characteristics. If I find my choice of 6" mid-bass drivers is not up to the job, I can replace them with something else and not throw away the crossover.

    Put the strongest amp on the lows, and the lesser powered amp on the highs. If you have the option, use balanced cables (TRS or XLR) for the *entire* signal path. Check out using a common chassis ground as well. The Rane site has everything you ever want to know in their RaneNotes PDF files. They offer everything you need in their Mojo line, and it appears to sell regularly on eBay.
  8. Thanks. While I must admit that 99.8% of that was over my head, I do appreciate the response. lol. I'll check out that site though.
  9. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    Pretty sure I never said it was silly. My recommendation is to try it if you're curious. I did it (bi- and tri-) and always got better results full range. Hardly any more work for my 15's to go above 200hz and my other cabinets always worked well down to their lower limits. It's very easy to get great sound without doing it. For the money you'll spend you could possibly just get a better amp and cabs.

    The other consideration is if you don't have a good enough crossover, one that allows you to overlap low and high pass, you may end up with a hole in the sound.
  10. MikeyD


    Sep 9, 2000
    Some opinions from MikeyD. I think in bgavin's case, bi-amping might make sense, because he has speakers that have vastly different operating ranges. For most of us who have speakers with overlapping ranges (an array of typical 10's and 15's, for example), bi-amping doesn't make a lot of sense - full range makes better use of the speakers' capabilities. Exceptions are if you like a big notch in the midrange or if you want to apply different effects to low and high channels. I run full-range most of the time with my stacks (2x10 and 2x15 or 1x18). However, since I drive the cabinets with a stereo amp, I attenuate the lows in the high side to protect the 10's from excessive cone excursion.

    bgavin - I'm a bit skeptical that active crossovers, unless they are digital, don't have "phase" issues, if I understand your comment. Analog filters do shift phase to some degree - something I think about when I twiddle my graphic EQ. Anyway, your other comments were good.

    One of the things that Spacegoat (I believe) has pointed out is that sometimes it's nice to have nearly as much power for the highs as the lows - particularly if you don't use compression and do percussive stuff, such as slapping. The resulting transients require an amazing amount of power to produce cleanly, and my own experience tends to back this up. So for the lows, you need lots of continuous power capability and for the highs, lots of transient overhead capability.

    - Mike
  11. Phasing is a problem introduced by the L/C components of passive crossovers. The Linkwitz-Riley 4th order design was the (brilliant) solution to phasing issues, and is the big selling point for this design. Also, live bass playing is not audiophile HiFi reproduction. I doubt ANYBODY could hear the subtle phase differences of a 2nd order network in the live environment.

    I've been digesting all the Rane technical notes, and find them very enlightening. And humorous. Rane uses L/R 4th order methods to keep the radical slope and correct the phase issues, but they do it without using large inductors. IMO and this is strictly opinion, I have great confidence in the Rane designs. Just a gut feeling from examining all their engineering.

    I would take Spacegoat commentary pretty much as gospel.

    I don't slap, but I still agree with having lots of head room for the transients. Seeing one on a scope should be enough to convince anybody. This is my first foray into bass bi-amping, and I may very well have to replace the 6" mid-bass drivers with something more substantial. I'm thinking about a pair of E-110s if I have to go that way.

    The nice part about active crossovers is I can adjust the frequency or replace drivers without rebuilding the crossover network. Plus, I have control over the gain on each channel.

    At first, I'll be running the MX-3000a in stereo, which will give me 1200w for each channel at 4 ohms. If this is insufficient, I'll run the 3000a as bridged mono at 3,000w and use a second amp for the highs. That will be trial and error from playing live.