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Thread: How to Bi-amp and maybe Tri-amp

  1. #1
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    How to Bi-amp and maybe Tri-amp

    Can anyone provide me with basic guidance on how to bi-amp or tri-amp a set of speakers? I made some DIY cabinets that have E145-8 for the low end 2440 drivers for mid range and 075 tweeters. I am currently using the LX5 and N7000 for my crossovers.
    I would like to purchase a 2 or 3 way electronic crossover, and I guess my basic questions are:
    If I Bi-amp will I need 2 amplifiers? My guess is the question answers itself. Yes
    If I do a two way crossover with a three way system, would I still need the passive crossover for the mid and highs?
    Is there any schematics that I could refer to?
    Does all the power go into the crossover and get divided and distributed from there to the different speakers?
    Does it matter if the high frequency amp is Class A and the low frequency power is Class A/B?
    Years ago I heard a bi-amp'd pair of 4350's and it was quite impressive but I never bothered to look at how it was wired up.
    I hope these are not really dumb questions
    Thanks in advance.
    Bill Goodhope

  2. #2
    Senior Member Val's Avatar
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    Passive crossovers divide power amp output between various drivers.

    Active crossovers divide pre-amp output between power amps which in turn drive the speakers.

    I'm considering tri-amping my LE15A/372/075 rig and have attached a draft diagram I've been working on. Comments welcome.
    Attached Images Attached Images  

  3. #3
    Heather [Senor member] hjames's Avatar
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    Many folks do biAmp by splitting the bass leg off their existing crossover, and using an electronic crossover to feed 2 power amps.
    In this configuration, the low split goes directly to a high power amp that feeds the Woofer directly.

    The high split goes to the passive that feeds the mid and high F drivers.
    Because its easier to hear noise among the high Freq drivers, you want the quietest amp on the high split. The Bass amp can be a bit lesser quality but higher powered.

    The quality of your electronic crossover will also affect your ultimate sound - if you buy a cheap, noisy crossover, it can overcome any advantage you gained by biamping.

    Do you have any existing amp gear? I tried doing this first with an older receiver and found my Front preamp out levels weren't really high enough to drive the crossover properly, so I had to run the levels higher and, again, wound up with more noise ...

    I got a better receiver and that is now working fine. But many folks feel the only worthwhile way to REALLY do this is using separate components (Preamp, etc) and not using a "receiver" as the front end ...

    I suffer with the receiver because I like the convenience of a remote for everything ...

    Quote Originally Posted by Bgoodhope View Post
    Can anyone provide me with basic guidance on how to bi-amp or tri-amp a set of speakers? I made some DIY cabinets that have E145-8 for the low end 2440 drivers for mid range and 075 tweeters. I am currently using the LX5 and N7000 for my crossovers.
    I would like to purchase a 2 or 3 way electronic crossover, and I guess my basic questions are:
    If I Bi-amp will I need 2 amplifiers? My guess is the question answers itself. Yes
    If I do a two way crossover with a three way system, would I still need the passive crossover for the mid and highs?
    Is there any schematics that I could refer to?
    Does all the power go into the crossover and get divided and distributed from there to the different speakers?
    Does it matter if the high frequency amp is Class A and the low frequency power is Class A/B?
    Years ago I heard a bi-amp'd pair of 4350's and it was quite impressive but I never bothered to look at how it was wired up.
    I hope these are not really dumb questions
    Thanks in advance.
    Bill Goodhope
    2ch: RPi-4, Oppo, Acurus RL-11, Carver TFM-25, VonSchw VR-4, Heath AS-1348, JBL L212 (2pr)
    7: TIVO, Oppo BDP103D, B&K, UREI 809A, JBL B460

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    Senior Member Val's Avatar
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    Quote Originally Posted by hjames View Post
    I suffer with the receiver because I like the convenience of a remote for everything ...
    Are you using receiver that has pre-amp outputs for all channels? Is that 5.1?

    Thanks!

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    Marchand electronics - X-over specialist, info

    Quote Originally Posted by Bgoodhope View Post
    Can anyone provide me with basic guidance on how to bi-amp or tri-amp a set of speakers? I made some DIY cabinets that have E145-8 for the low end 2440 drivers for mid range and 075 tweeters. I am currently using the LX5 and N7000 for my crossovers.
    I would like to purchase a 2 or 3 way electronic crossover, and I guess my basic questions are:
    If I Bi-amp will I need 2 amplifiers? My guess is the question answers itself. Yes
    If I do a two way crossover with a three way system, would I still need the passive crossover for the mid and highs?
    Is there any schematics that I could refer to?
    Does all the power go into the crossover and get divided and distributed from there to the different speakers?
    Does it matter if the high frequency amp is Class A and the low frequency power is Class A/B?
    Years ago I heard a bi-amp'd pair of 4350's and it was quite impressive but I never bothered to look at how it was wired up.
    I hope these are not really dumb questions
    Thanks in advance.
    Bill Goodhope
    See attached - lots of DIY info, products: http://www.marchandelec.com/

  6. #6
    Heather [Senor member] hjames's Avatar
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    Quote Originally Posted by Val View Post
    Are you using receiver that has pre-amp outputs for all channels? Is that 5.1?

    Thanks!
    OK, I have a cheapie Hk AVR335 I think - something like 60w/ch
    it can do 7.1 but I run it in 5.1 mode.
    I can add amps for the other channels, or upgrade to a higher power HK receiver if I had a larger room or needed more power.

    I use the internal amps for the surround channels, they only run when I'm playing surround sources
    (TV/TIVO/DVD/DVD-Audio/SACD/etc)
    For music the system pretty much drives just the 2 front mains via biamp

    HKs rear amp outputs feed the pair of L20Ts hanging in the back.
    HK Center amp output feeds a JBL LC2
    HK Sub preamp out feeds an old Hk Citation 22 in bridged mode and that feeds a JBl B380 sub ...
    HK Preamp out Front L/Front R go to biamp system rack below ...



    For the BiAmp stuff ...
    Front L & R preamp out feeds Yamaha 31band EQ,
    that feeds Ashley XR 1001 active crossover -
    high split feeds JBL/UREI 6230 amp
    Low split feeds JBL/UREI 6260 Amp (but I'm on the verge of replacing that with a 6290 amp for more headroom).

    The Top unit is an Adcom sequenced power switcher, powers the accessories up first & the amps up last
    and powers the amps down first and accessories last to avoid thumps.

    2ch: RPi-4, Oppo, Acurus RL-11, Carver TFM-25, VonSchw VR-4, Heath AS-1348, JBL L212 (2pr)
    7: TIVO, Oppo BDP103D, B&K, UREI 809A, JBL B460

  7. #7
    Senior Member Val's Avatar
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    Very helpful...thanks

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    Senior Member 1audiohack's Avatar
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    Can anyone provide me with basic guidance on how to bi-amp or tri-amp a set of speakers?
    I live in Las Vegas and have a bunch of idle gear, if I can help give a yell.
    Barry.

  9. #9
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Val View Post
    Very helpful...thanks
    Hey Val, I am regularly in the PA area... and I have a pile of active crossovers that are not in use. I could lend you an Ashley, Rane, or Audio Arts... I have others that are also in storage, but they are either too expensive, too rare, or not quite working...

    send me a PM if you'd like a loaner and help with set up.


    Widget

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    Senior Member Tweak48's Avatar
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    http://i160.photobucket.com/albums/t181/tweak48/Garage1.jpg

    Quote Originally Posted by Bgoodhope View Post
    If I do a two way crossover with a three way system, would I still need the passive crossover for the mid and highs?
    That's what I did with my L-300s, and they sounded much better this way than with the stock set-up. I used a low end (as in cheap) dbx 2 way crossover and ran the LF through a solid state amp directly to the woofers. Used a tube amp for the mids and HF, into the internal L-300 passive network.

    It really opened things up on the top, and man that s/s amp ruled those 136 woofs with an iron fist!!!

    Good luck!


  11. #11
    Senior Member Val's Avatar
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    Quote Originally Posted by Tweak48 View Post
    That's what I did with my L-300s...It really opened things up on the top, and man that s/s amp ruled those 136 woofs with an iron fist!!!
    Good to hear. What is the crossover freq of the 136 in your active rig?

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    Senior Member Tweak48's Avatar
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    Quote Originally Posted by Val View Post
    Good to hear. What is the crossover freq of the 136 in your active rig?
    The crossover frequency of the dbx is continiously variable; I set it at 900hz. As I remember, the cross point on the passive internal network is 800hz, so it set the active one a bit higher so as not to get in trouble with the passive network.

  13. #13
    Senior Member Val's Avatar
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    Quote Originally Posted by Tweak48 View Post
    The crossover frequency of the dbx is continiously variable; I set it at 900hz. As I remember, the cross point on the passive internal network is 800hz, so it set the active one a bit higher so as not to get in trouble with the passive network.
    Thanks!

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    Junior Member loman69's Avatar
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    Hi all,

    i would like to know that how to conect my so-called 2 ways 4344 system properly.

    Connection 1: all output signal from preamp(left & right channel) go directly into my JBL M552, then the crossover divide it into HF & LF.
    HF goes into the passive crossover of 4344
    LF goes directly into the the woofer

    problem: the HF went through 2 corssovers(both M552 and internal passive crossover of 4344)

    Connection 2: my friend gave me a Y cable so the output singal from the preamp can be devided into 2.
    Singal 1(from 20-20,000hz) simply goes directly into internal passive crossover of 4344
    Singal 2 goes to M552, then the LF(from 20-320hz) goes directly into the woofers

    For me, i perfer connection 2 because the coherence and the deeper bass.

    Am I doing it right?

    Joel

  15. #15
    JBL 4645
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    Val

    Like the diagram of the four-way tri-amp crossover. I’m only running basic two-way with DCX2496 LF and HF for JBL control 5 LCR. Like very much to get a few more DCX2496 and extend it further over what it is, but I’m quite pleased with its performance.

    Basically with an active crossover which is what makes the sound clearer and it’s benefits of lower lows and higher highs with less distortion, excellent.

    Sub bass diy JBL 4645 hasn’t at yet got its own crossover since the LFE.1 has its own cut-off at 120Hz and when used with Dolby stereo 4:2:4 films I select the (sw-re-mix) mode t reroute the low end to the JBL 4645.

    I run a second sub Eltax A 12-R but its no where as good as the JBL its fine for extending the lows for the JBL control 5, and the x10 JBL control 1 that are fixed around the room in horseshoe shape.

    One thing I find that is peace of mind with the DCX2496 is level control via its input and output LED display its dynamic EQ and audio limiters for loudspeaker portion.

    Only one cinema in the UK uses (Loudspeaker Management Crossover System) dbx4800 at the Empire Leicester Square which is tri-amp 56KW and its out of this world with the custom JBL install, out of this world its like a breath of fresh Springtime air, which I’m waiting for, flipping cold at the moment. LOL

    Home system
    Kenwood KRF-X9050D THX select Dolby/dts 5.1
    Yamaha DSR70Pro for sub bass left and right extension and upper centre channel decoding. it also acts as a preamp for left and right that feeds off to inputs channel A and C on the DCX2496

    Yamaha DSP100 for centre channel for centre sub bass extension. the unit then feeds off to channel B on the DCX2496.

    Pioneer VSP-200 that acts as preamp for surrounds and centre back surround decoding as well as matrix overhead channel output that is amplified only, doesn’t support RCA phone out, except for left and right centre and (sub bass which is used to extended the lows of the surrounds)

    A few extra basic dinosaurs EQ that is used for left and right fronts as spectrum analyzer monitor. A EQ with spectrum analyzer for centre and (centre back arrays channel that is used to trim the back surrounds) (and one for the sidewall arrays surrounds that is used to trim the surrounds).

    I use an audio mixer that has the low end for custom in-room tailoring
    Audio mixers inputs

    1 Left and right summed
    2 Centre
    3 Left and right surround summed
    6 LFE.1

    Each one has its own fader slider so I can trim the level to suit the most problematic issues in the LCRS as S tends to mask the centre too much on Star Trek III when the Klingon kills captain Kirk’s son, “You Klingon, bastard” LOL.

    the primary full range channels are then feed from the two Yamaha DRS70Pro and DSP100 to over to the DCX2496 where crossover for LF LCR is selected (Bessel -12db 80Hz and Linkwitz-Riley -24db 1Khz) (its presently set at 805Hz) why because it adds a warmer feel on the JBL control 5.

    HF for LCR is set at Linkwitz-Riley -24db 1Khz.

    Each of the LF is powered by Alesis RA300 150watts 4ohm
    Each of the HF is powered by my old but she’ll still hold Marartz 1050 amps that are rated I think at 65watts per side
    Centre back surround is powered by one Alesis RA300
    LFE.1, JBL 4645 is powered by x1 Alesis RA300 in bridge mode no issues as of far.
    sidewall surrounds is powered by Marantz 1030

    All the remaining Marantz amps are soon with Alesis RA300 or 500 or maybe other PA type soon.

    Finally x1 Behringer BFQ2496 for parametric EQ for JBL and Eltax A 12-R

    And that’s that.

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