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Full range or biamp

Discussion in 'Amps and Cabs [BG]' started by cubeenz, Oct 31, 2001.


  1. I'm thinking about adding a 15 to my 4x10 in order to get more low end. I'll be pushing both 8 ohm cabs with 450w total power. Do you think I will get much improvement running both cabs in full range? Or would it be better to biamp? I've never done this before, so I pretend I know nothing. :D
     
  2. BlacksHole

    BlacksHole

    Mar 22, 2000
    Rockville, MD
    I like to biamp, but there are many who say it cuts power, creates a hole in the tone spectrum, isn't necessary for bass, ... However, one advantage is that I use separate tone on the low signal from what I send to the high (crossover at 400) and I also use a touch of effects on the high end (such as chorus and verb). The only effect I sometimes add to the low end is a suboctave, which for obvious reasons I do not send to the high end.
     
  3. I Biamp. Right now I just have a 115 combo and a 110 combo but the sound I get out of biamping the two together is awesome. I get an awesome tone from my ADA MB-1 which is great when you get all of your low tones out of a thick juicy 15 and all your highs out of a punchy 10 it separates them perfectly and makes them sound great. I just wished I had a a more powerful 10. I will be getting a 1400 wat Mackie poweramp soon though so :D
     
  4. I bi-amp because it is mandatory for my rig.

    :D

    My subwoofers are useless above 100 Hz, so I use a pair of JBL E110 to handle the chores from 100 to 8000 Hz. For maximum protection to the E110s, I use a Rane MX22 crossover with a 24 dB slope to quickly isolate the JBLs from the lows that would otherwise destroy them.
     
  5. You have to try it and see what you like.

    The reason you might have less power is as follows:

    If you have a stereo amp that puts out (for example) 250 watts per side and your speakers cabs are essentially full range. Most of your power is required by the fundemental frequency. Let's assume you crossover at 200 Hz. Say you are playing a note at approx. 80 Hz. When you bi-amp, the fundemental will have the 250 watts available and the 1x15 to produce that tone. There will be harmonics that are sent to the 4X10, but the power used will be significantly lower than what goes to the 1X15. If, however, you run this full range, you will have 500 watts available and both the 1X15 and the 4X10 will push that 80 Hz fundemantal.

    Similarly, if you play a note that is above 200 HZ, with bi-amping, you have the 250 watts and the 4X10 for that fundemantal and harmonics. If the 1X15 is capable of that frequency, then full range mode would allow you to drive the other 250 watts and the 1X15 for these notes also.
     
  6. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    There are reasons to biamp... and reasons not to.

    Creating a hole is pretty common. Using a crossover with overlap capabilities can usually take care of that.

    Using effects on on one side of the biamp is a good reason... for example, you can affect the hi-pass without destroying your bottom. Then again, the multiFX unit I have (but rarely use) has 3 band semi-parametric EQ available for every patch so it's not an issue.

    If a low end driver is adding mud in the low mids or a high end driver breaks up on the lows, these would be good reasons to biamp.

    The trick, to me, is to match up the amps with speakers that work optimally in the ranges you want to operate them in. If you take a 410 that has excellent lows and cut them off you could be removing a palette of sounds not available with your low end driver(s). By the same token, reducing a 15 to a "thump" driver, even though it has excellent low mids, could be counter-productive.

    My advice... try full range first, you might be surprised.

    BTW why not send a sub octave to the high pass? IME it sounds pretty cool.
     
  7. 200 Hz is the 12th fret, G string.

    Crossing over at 200 Hz is a waste of resources for the 4x10 because it won't reproduce any fundamental... only harmonics. Crossing over at 55 to 80Hz makes best use both the 4x10 and the 15". But, I haven't seen any active crossovers the go below 70 Hz, and building a passive crossover would be very expensive and large/heavy. I wouldn't bi-amp a 4x10 and a 15", but would let each run full range and see how it sounds.
     
  8. I agree. 200 Hz seems high for the crossover. It was just an example and I use it because some bass amps with bi-amp capability have 200 Hz as the lowest crossover point. But whatever frequency you pick, any given fundemental will be supported by only one amp and one cab even if both cabs can handle that frequency. Therefore, you essentially get half the power that the amp is capable of. This is primarily an issue with the low frequency cabinet where massive power is required for the really low notes.

    This is why bi-amping is more popular in PA systems. PAs drive multiple frequencies simultaneously and so use both amps fairly well (if the crossover point is selected properly). Bass guitars normally are playing only one fundemantal at a time.

    What would make sense is a low cut filter for the 4X10s that would cut the frequencies below those that the cabinet can handle (maybe 50 Hz or so - depends on the cab) and full range to the 15. Some electronic crossovers will do that. Some external EQs will do that also.

    But I, too, would just run them full range first and see how it sounds.
     
  9. That's sort of what I had in mind. A lot of times in home theater and auto situations they use passive bass blockers, when sending full range signals to a variety of speakers. Would something like this work on a larger scale?
     
  10. BlacksHole

    BlacksHole

    Mar 22, 2000
    Rockville, MD
    Brad Johnson sez:

    BTW why not send a sub octave to the high pass? IME it sounds pretty cool.

    I don't like to do this for a couple of reasons. First, I crossover at 400 Hz, so I'm not realling sending much of anything from a suboctave to the high end. Nor do I want to as I use 2x8"s for the high and 1x15" on the low. I can't play a high enough note so that it's suboctave is over 400 Hz. Further, the 8s aren't really capable of doing a very good job at reproducing very low notes.
     
  11. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    Sounds like a pretty non-standard rig:)

    Your 8's won't go below 400hz? Do you also block everything above 400 from the 15 or run it full range?
     
  12. BlacksHole

    BlacksHole

    Mar 22, 2000
    Rockville, MD
    My amp is non-standard - it's a polytone pro. It is designed in this fashion and I use the crossover that is part of the amp. I do not know what level of crossover it is, but I do not think that it fully blocks notes as I would guess its a 12db xover.
     
  13. Luis Fabara

    Luis Fabara

    Aug 13, 2000
    Ecuador (South America)
    Audio Pro - Ecuador
    I run my Carvin R1000 Bi-Amped, it makes the sound of the 1x18" Clearer and Fatter.
     
  14. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    That's definitely non-standard;)(I have a MiniBrute II).

    I think cubeenz is asking about a bigger biamp rig. Unless he has some substandard 410 there really isn't much of a reason to block lows going to it. IME the combination of the lows from a 15 and 410 together was usually much nicer than a 15 alone.
     
  15. MikeyD

    MikeyD

    Sep 9, 2000
    Yes - I do it with my Carvin R1000 and/or R600 heads. I insert a capacitor in the preamp send/power amp return in Channel 2 to "block" (actually "attenuate" is more accurate) the lowest frequencies to my 2x10. This lets the 2x10 get full signal above about 120 Hz., yet I run my Eden 2x15 (XLT) full-range from Channel 1. I get the maximum power without killing the 10" drivers with excessive low bass. It works great, but I had to experiment a little with the capacitor value to get a high-pass (1st order) filter corner frequency that would sound good and do the job. Read my earlier posts on the subject: I found that running the Carvins in bi-amp mode wasn't making it. This capacitor was the solution to my problem.
    - Mike
     
  16. Brad Johnson

    Brad Johnson Commercial User

    Mar 8, 2000
    Gaithersburg, Md
    Boom Bass Cabinets, DR strings
    Great solution, Mike. Most people seem to consider biamping running a lowpass AND highpass when it actuality running one cab full range while limiting the other can be more pleasing.
     
  17. Bi-amping or tri-amping is using each driver exclusively within its designed frequency range. This provides maximum efficiency by restricting the driver to only those frequencies it is designed to reproduce. Maximum safety is a by-product of bi-amping because the driver is never subjected to frequencies that would physically damage it. However, a user can still over power the driver and blow it up.

    All signal segregation is done upstream from the power amps. A high-end active crossover such as the Rane AC23 3-way unit downstream from the preamp handles the frequency separation without the problems inherent in passive crossover networks. The Rane AC2x series allows for signal delays to correct for driver diaphragms that are not located in the same vertical plane. This is overkill. The Rane MX22 mojo series active crossover is much less expensive and ideal for bass rigs.

    For the question posed here, I would still opt for running both the 4x10 and 1x15 as full range to see how it sounds. The intent is having the 15 supplement the low end of the 4x10. Running both full range will provide more bottom than a single 15 in bi-amp mode. If the 1x15 has a tweeter, consider turning it off.
     
  18. I prefer running both speakers in full range, and adjusting the level between the two and sometimes cutting highs or boosting bass in one cab if suitable.

    Aloha,

    Jonathan
     
  19. OK, I`m a dummy but....

    I think I know what biamping is but not 100% sure.
    Is that when you run your highs/mids to one cab and then run your low mids/lows to another separate cab??In effect creating two seperate mini-amps or...?

    Also...what is a bass driver? Like a sort of power amp for just the lower freq.? :confused:


    Thanks!
     
  20. Bi-amping is not defined by cabinets but by drivers. Each driver or driver group is attached to its own amplifier channel, even if the driver group spans multiple cabinets. Any stereo power amp can use one channel for lows and the other channel for highs. If you are tri-amping, you will need a third amplifier channel.

    A bass driver is a cone speaker that is designed to reproduce low frequencies. A tweeter is designed to reproduce high frequencies. If you expose the tweeter to bass frequencies, it will be destroyed. You can bi-amp this configuration, but it is easier here to use a crossover to protect the tweeter.

    A more realistic bi-amp situation is using subwoofers and midrange drivers. Most subs are all done by 100 Hz. Any signal higher than this is wasted in a sub. My E110s cannot stand exposure to low bass frequencies, but they really crank from 100 Hz and higher. My Rane crossover puts 100 Hz and lower into Channel 1 of the amp which connects to the subs. The crossover puts higher than 100 Hz into Channel 2 of the amp which connects to the E110s.