Another question about bi-amping...

Rike255
Rike255 Posts: 131
edited February 2008 in Electronics
Sorry I know there are a lot of topics about bi-amping and I think I get the just of it but just one more thing:
So the 805 has the capability to bi-amp the front speakers. From what I understand this really shouldn't make a big difference because it's all being driven from the same amp anyways and there's only so much it can do. I'm assuming this is all still true when I'm only driving the two fronts, no other speakers right? However, I've been hearing people saying things like "Bi-amping makes a huge difference in SQ if used with crossover". What exactly does this mean and how does it make it better?

Thanks!
Polk Audio RTi8 Fronts
Polk Audio CSi A6 Center
Polk Audio RTi A3 Surrounds
Polk Audio PSW505 Subwoofer
Onkyo TX-SR805
Sony Bravia V5100 46"
Sony Playstation 3 160GB
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  • Systems
    Systems Posts: 14,872
    edited February 2008
    Rike255 wrote: »
    However, I've been hearing people saying things like "Bi-amping makes a huge difference in SQ if used with crossover". What exactly does this mean and how does it make it better?
    It means that the crossover is done ahead of the amplifiers using an active crossover which is basically a component somthing like a preamp as it uses op amps.It replaces the normal passive crossover with its power robbing inductors ,resistors and capacitors.Here is a link that describes the benifits of active systems.http://sound.westhost.com/biamp-vs-passive.htm
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  • joeparaski
    joeparaski Posts: 1,865
    edited February 2008
    Rike255 wrote: »
    Sorry I know there are a lot of topics about bi-amping and I think I get the just of it but just one more thing:
    So the 805 has the capability to bi-amp the front speakers. From what I understand this really shouldn't make a big difference because it's all being driven from the same amp anyways and there's only so much it can do. I'm assuming this is all still true when I'm only driving the two fronts, no other speakers right? However, I've been hearing people saying things like "Bi-amping makes a huge difference in SQ if used with crossover". What exactly does this mean and how does it make it better?

    Thanks!


    In a bi-amped system, the pre-amp sends the signal to an external crossover. The crossover has two outputs, one sends the "highs" to the amplifer designated for highs and the other output sends the "lows" to the amplifer designated for the lows. The built-in "passive crossover" inside the speaker is not used. The external "active crossover" usually has settings that you can adjust manually.

    The sound is usually better because the 2 amplifiers share the load instead of one. Although some suggest the use of 2 identical amplifiers, I have not had any issues using a more powerful amp for the lows and a less powerful one for the highs.

    Joe
    Amplifiers: 1-SAE Mark IV, 4-SAE 2400, 1-SAE 2500, 2-SAE 2600, 1-Buttkicker BKA 1000N w/2-tactile transducers. Sources: Sony BDP CX7000es, Sony CX300/CX400/CX450/CX455, SAE 8000 tuner, Akai 4000D R2R, Technics 1100A TT, Epson 8500UB with Carada 100". Speakers:Polk SDA SRS, 3.1TL, FXi5, FXi3, 2-SVS 20-29, Yamaha, SVS center sub. Power:2-Monster HTS3500, Furman M-8D & RR16 Plus. 2-SAE 4000 X-overs, SAE 5000a noise reduction, MSB Link DAC III, MSB Powerbase, Behringer 2496, Monarchy DIP 24/96.
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  • ShinAce
    ShinAce Posts: 1,194
    edited February 2008
    The problem exists with the speakers themselves. If they were 8 ohms at all frequencies, we'd only have DC resistance to cry about. Since they vary in impedance, they vary in how they behave with the crossover.

    By using an active crossover before the amp, you are guaranteed to get the correct roll-off at the correct frequency. You're getting a more precise solution and therefore better SQ.
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  • Early B.
    Early B. Posts: 7,900
    edited February 2008
    So if I understand this correctly, in order to use an external crossover, you'll need to disengage the internal crossover in the speakers and hook the drivers up directly to their respective binding posts?

    Is there a way somehow to keep the internal crossover intact and use an external crossover, too? I wouldn't want to perform major surgery on my speakers, but I'm intrigued by the external crossover concept.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • ShinAce
    ShinAce Posts: 1,194
    edited February 2008
    External crossovers are great when the impedance of a driver is erratic or you are dealing with many crossover points(4-way systems).

    If you're trying to get an external crossover to replace an internal 2-way one, you are going to great effort for very little gain.

    No, you can't keep the internal crossover and have true bi-amping. If the internal crossover happened to be a 3rd order, I might suggest a cheap fix, but not in this case.
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  • Early B.
    Early B. Posts: 7,900
    edited February 2008
    Oh, I ran across this thread....

    http://www.audiocircle.com/circles/index.php?topic=50711.msg455132;topicseen#new

    It appears as though Brian at VMPS figured out how to design a speaker to accomodate both passive and active crossovers.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • ShinAce
    ShinAce Posts: 1,194
    edited February 2008
    The only way I can see this working is with odd order crossovers. This is great if you want to build a new speaker from scratch to fit the bill, but not useful for converting existing crossovers(generally even order).

    This diamond is still in the rough.
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  • joeparaski
    joeparaski Posts: 1,865
    edited February 2008
    I use electronic crossovers to bi-amp my SRS and my 2.3 tl's. The existing passive crossovers are also used. I recall reading it in the manual that came with the speakers that this option can be used.

    Joe
    Amplifiers: 1-SAE Mark IV, 4-SAE 2400, 1-SAE 2500, 2-SAE 2600, 1-Buttkicker BKA 1000N w/2-tactile transducers. Sources: Sony BDP CX7000es, Sony CX300/CX400/CX450/CX455, SAE 8000 tuner, Akai 4000D R2R, Technics 1100A TT, Epson 8500UB with Carada 100". Speakers:Polk SDA SRS, 3.1TL, FXi5, FXi3, 2-SVS 20-29, Yamaha, SVS center sub. Power:2-Monster HTS3500, Furman M-8D & RR16 Plus. 2-SAE 4000 X-overs, SAE 5000a noise reduction, MSB Link DAC III, MSB Powerbase, Behringer 2496, Monarchy DIP 24/96.
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