Using a 5 Channel Amp To Bi-Amplify?

Discussion in 'Archived Threads 2001-2004' started by Brett DiMichele, Sep 6, 2002.

  1. Brett DiMichele

    Brett DiMichele Producer

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    Hey All,

    It has come time to do some upgrading and my focus is for
    both movies and music I want to do both equaly as well as
    the other.

    My problem is that my TX-DS787's 100wpc does not power my
    AR9 mains very well. Complex Passages that are heavy on the
    lows tend to send the Receiver into Thermal OverLoad Protection.

    If you compare the AR9 to the AR5 the sole difference is
    that the AR5 contains one 175 Watt Mono Carver Sunfire TDC
    Amp in each speaker cabinent who's sole duty is to drive
    that 10" Bass Reflex Subwoofer.

    I didn't want a "powered sub" because there is far more
    flexibility with non powered for setup purposes. So I find
    myself wanting to Bi-Amplify my 9's.

    I have been pondering how I want to go about doing this. In
    one respect I could go for straight out 2Channel and buy 4
    moderate MonoBlock amps like the nOrh LeAmps or I could go
    with a more Home Theater biased 5 Channel Amp which could
    be setup for 2Channel and Home Theater.

    So what I am thinking is could I do this... I want the
    Parasound HC2205-AT which delivers 220 Watts Per Channel
    by 5 Channels. I was thinking that I could use this in two
    diffrent and unique setups. On the one hand I can run all
    of the seperate channel outputs of the 787 into the ParaSound
    and that would hook me up with plenty of power for Home Theater.

    And then I could also use Left/Right Front and Left Right
    Rear Surround's all linked together to the Left/Right Front
    outputs of the 787 so that I could send 440 Watts to each
    AR9, 220 Watts for the Sub and 220 Watts for the Mids/Highs
    in a Bi-Amplify config.

    Both ways the volume and everything would be controlled via
    the 787 wich saves me from having to buy a seperate Tuner
    and PreAmp for 2Ch. I will use the 787 as the source switcher
    and Tuner but I am sure I could hook this all up to be switchable
    for 2Ch or Multichannel.

    Of course I would have to use splitters so that I could plug
    all these outputs into the Parasound.

    Am I crazy ? Or is what I am concieving founded in logic?

    Any suggestions?

    My ears are open.
     
  2. John Kotches

    John Kotches Cinematographer

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    Brett,

    Might I suggest you start with single-wiring your Front L/C/R and driving the passive subwoofer with the 4th channel instead? This leaves one unused channel, but still might be worth pursuing.

    You might find that the 220wpc/8ohms of the Parasound amp will be miles ahead of the 100wpc from your receiver, which would eliminate the biamping.

    Just something to consider.

    Regards,
     
  3. WillieM

    WillieM Stunt Coordinator

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    I am currently using a Denon AVR882(90wX5)reciever and plan the following upgrade (which I did pass by my AV consultant who said it sounded like a stellar idea).

    Purchasing 2 new amps; the Parasound HCA-1205A (140wX5) and the Parasound HCA-1000 (125wX2). Using the Denon as a pre-pro only.

    I am running PSB Image series all around (5T fr L/R, 9C ctr, 2B rears). The front 5T's are bi-ampable.

    I will use the 1205 to run the tweeter/mids up front (less drain on the amp than the woofers) and all other speakers, and use the 1000 to drive only the one 6-1/2" woofer in each of the front speakers. 125W per 1 speaker each should be more than enough power.

    The 5ch amp should therefore not be over drainied and the 2ch can most certainly handle 2 speakers.

    MSRP on the HCA-1205 is $1199/ the HCA-1000 is $650. total is only $1849 vs the $1999 for the HCA-2205.
     
  4. Brett DiMichele

    Brett DiMichele Producer

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    John,

    The problem is I have 2 Passive 10" Subs not just one, and
    they each need at least 150 watts to run them efectively.

    My reasoning behind the 2205 is that 220 watts per channel
    will leave me lots of head room and power should never be
    a factor after that upgrade.

    I could always just buy an external sub and disconnect the
    sub portion of my 9's but that kinds defeats the whole reason
    for buying near full range towers.

    *Scratches Head* I dunno... I like the 2205 anyway so I can
    get it and see if I can work it in.. I am sure I can!

    I just kinda wanted to see if what I was scheming was doable
    or if 4 monoblocks for the mains would be better. Monoblocks
    will be more hassle though.
     
  5. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Are the AR9s a 3 way speaker? if so you will have a 3 way X-over to deal with also. If not and if you feel like some minor DIY you could buy 2 250 watt sub plate amps and drive them from your sub out on the receiver. I have the Onkyo 787 and a powered M&K sub, the system will hit 108dB clean at my listening position, if I want it that loud. The sub is done at 94 dB though so I am working on that with a DIY sub.
     
  6. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Then look here
    http://www.partsexpress.com/pe/pshow...=300-794&DID=7
    you could build a small inclosure for the amp, and run it from the sub out with a "y" rca cable to each amp. The neet thing about this is you have the x- over and phase adjustments and an optional bass boost ( in a diferent part number)and on the plate amp. BTW it does not have to be mounted in the speaker box, lots of guys who build sonotube subs mount them in thier own box. Look here from a fellow HTF admin Patrick Sun
    http://www.io.com/~patman/ampbox.html
     
  7. Brett DiMichele

    Brett DiMichele Producer

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    Mark,
    That is a definate idea to consider, in fact I have thought
    about it already. I looked at the remote controled version
    of the P.E Plate Amps.. I could easily mount a plate amp
    in each cabinent (directly across from the sub woofers) and
    I don't think I would affect cabinent volume much at all.
    But I kinda want that big ass ParaSound amp! [​IMG]
    Sure I could save a ton of money going with plate amps
    and then my 787 could send it's 100wpc to those dual 5.25
    and 1" tweets which it powers those with ease.. But I dunno
    I got the hankerin for one BIG amp.. I have an open space
    in my audio rack [​IMG]
     
  8. Brett DiMichele

    Brett DiMichele Producer

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    Ya know what.. The more I think about it this would most
    definatly be the much easier way to go.. My Onk has enough
    headroom to run the center, surrounds and the mids/highs
    of the 9's with no problem.. I think I am just going to
    order two of the PE Plate Amps and mount them in a rack
    mount enclosure and mount them in my audio rack and just
    run the speaker lines over to my 9's.. I really don't want
    to mount them in the 9's because well I just don't want to
    do that..

    For now I think this setup will cure my problems.. Later
    I will step up to a larger 5 channel amp.
     
  9. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Then you will also need 2 active subwoofer crossovers. You have me thinking down the road of active cross-overing my system. I am a DIY at heart and am in the process of redesigning my system to be my designs. Just finished my center channel, next is the sub(s). Then it is off to the mains. Good luck
     
  10. Mark_E_Smith

    Mark_E_Smith Second Unit

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    What is your understanding of the bass managment of the 787, I thought it only applied to the DTS, DD and THX settings. I may be wrong, cant find anything in the manual.
     
  11. John Kotches

    John Kotches Cinematographer

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    Mark,

    Do not underestimate matched amplification, given that you have a pair of 10" passive subs to drive, my recommendation would be:
    L/C/R + the subs.

    Regards,
     
  12. Mark_E_Smith

    Mark_E_Smith Second Unit

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    John, my only concern would be lack of a crossover for the subwoofer, his concept is great and I generally agree with his approch. If the receiver rolls of the sub with a 2nd order at 100 to 125 Hz and has some kind of high pass at 15 to 20 Hz this would be fine and you wouldnt need an additional x-over.
    Brett, I know allot of people use a crown amp to run their homemade subs, you might ask the x-over / bass management question over at the DIY / advanced projects section of this forum.
     
  13. John Kotches

    John Kotches Cinematographer

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    Mark,

    Yes, I've made the assumption the receiver has a competently designed filter for the subwoofer. If it's THX badged the high pass portion of the subwoofer filter will be in place (by requirement).

    The Low-pass filter (in this case your basic subsonic filter) could easily be placed inline between the receiver and amplifier.

    The catch is that there is material being delivered below 16Hz nowadays.

    Regards,
     
  14. Brett DiMichele

    Brett DiMichele Producer

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    John,
    Seeing as my 10's will never see 16hz I guess I won't know
    what I am missing till I go to dedicated sub woofage! [​IMG]
    I will eventualy pick up one of AR's ARS500's if I can find
    one for the right price and do some experimenting. At that
    time I will need better bass management to be able to run
    a dedicated "LFE" sub and use the mains just down to a certain
    cutoff.
    This stuff gets confusing! [​IMG]
     
  15. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Ok rereading the posts I missed the post about you using the PE plate amps. They have all you need. I would use the sub out to the PE plates and I bet that will sound great! Most likely as good as the AR5s [​IMG]
    John, there have been reports that some of the new DVDs (Lord of the Ring, and U457(?)) are infact going down into the teens esp on explosions, but that is getting into the range of mechanical shakers.
    BTW Brett I looked at your HT set up on your site, I have the same a/v rack as you. Did you have a pronto? Also you might consider building your own sub(s)later. There are some neat drivers out there and you can get an incredible sub for 1/3 the price of a comercial sub.[​IMG]
     
  16. Brett DiMichele

    Brett DiMichele Producer

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    Mark,
    I figured the PE Plates had all I needed that was why I was
    scratching my head over the need for seperate bass management! [​IMG]
    I bet with the PE Plate Amps they will OUTDO the AR5's!
    I had a Sima SUR-20 (Same as the Crisp Solutions UC515)
    now I have a Pronto Pro TSU6000 gawd I love that remote! [​IMG]
    Cool audio rack.. For the price! Of course Salamander makes
    some that are to die for.. But the prices.. Yeowch!
    It suits my needs. Holds all the junk!
     
  17. John Kotches

    John Kotches Cinematographer

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    Mark:
    The THX intro and Phantom Menace are in the 10Hz range......
    Yee haa... Just a few Hz lower and we'll have DC to reproduce [​IMG]
    Regards,
     

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