RMB-1066: Configuration Question

Discussion in 'Archived Threads 2001-2004' started by John Dunlap, Jul 27, 2002.

  1. John Dunlap

    John Dunlap Stunt Coordinator

    Joined:
    May 8, 2002
    Messages:
    157
    Likes Received:
    0
    Trophy Points:
    0
    I just purchased a new RMB-1066 amp which I am using to drive my 3 fronts-Paradigm Studio 60's and CC. I am wondering whether I am better off bi-amping (Yes, fool's bi-amping) these speakers with 60 watts going to the HF and LF terminals or bridging at 150W in a non bi-amp configuration. Which is better? Any thoughts?
     
  2. Mark C.

    Mark C. Supporting Actor

    Joined:
    May 21, 1999
    Messages:
    557
    Likes Received:
    0
    Trophy Points:
    110
    The only answer is to try them both ways and see which method sounds best. 60W should be enough for your front three to allow biamp.

    Good Luck

    Mark
     
  3. Mark Rich

    Mark Rich Second Unit

    Joined:
    Oct 24, 2001
    Messages:
    457
    Likes Received:
    0
    Trophy Points:
    0
    In my HT set-up I use Studio 60's and CC powered with a Rotel 1075. The 60's are bi-amped and I highly recommend it. I agree with paradigm that it provides a dramatic improvement in detail and definition.
     
  4. Daniel Lindgren

    Daniel Lindgren Stunt Coordinator

    Joined:
    Jun 16, 2002
    Messages:
    53
    Likes Received:
    0
    Trophy Points:
    0
    A swedish hifi-mag recently tested the RMB1066 and strongly recommended against bridging to 3x150, because it sounded (and measured) a lot better in 6x60 mode.

    The all around winner in the test, if anoyone cares, was the RMB1066 beacuse of its unbeatable price/performace ratio. The best sounding (and best measured) amp was the Primare A30.3, a lot more expensive and only 3 channels, but worth the extra money if you have it - according to them.
     
  5. Kevin. W

    Kevin. W Screenwriter

    Joined:
    Oct 27, 1999
    Messages:
    1,534
    Likes Received:
    0
    Trophy Points:
    0
     
  6. Lando P

    Lando P Agent

    Joined:
    Apr 15, 2002
    Messages:
    40
    Likes Received:
    0
    Trophy Points:
    0
    I also have the RMB-1066 and tried the bi-wire configuration on my right front speaker while leaving the left front on a bridged mode. While listening in stereo mode, I switched the balance between the two main speakers. I liked the bi-wired set-up compared to the bridged one. The left speaker seemed muffled compared to the bi-wired. The bi-wired had more detail and depth. Nevertheless, the bridged mode still sounds better than with just the a/v receiver. But that's just me. Others may have a different perception.

    I have an HK-510 receiver using as pre-amp(and powering my rears) and Aegis 3 (Acoustic Energy) speakers for my mains.
     
  7. Daniel Lindgren

    Daniel Lindgren Stunt Coordinator

    Joined:
    Jun 16, 2002
    Messages:
    53
    Likes Received:
    0
    Trophy Points:
    0
    Kevin: Sorry, they don't have a website ... at least not accessible to me, the address is www.hifi-musik.se, but the only thing I get is an "access forbidden".
    Unbelievable that they don't have a web site, but som hifi mags seem to live in the computer stone age.
    Probably because they can't have an analog web site ... [​IMG]
    Anyway, you can send an e-mail to this address: [email protected] if you want to contact them.
     
  8. John Dunlap

    John Dunlap Stunt Coordinator

    Joined:
    May 8, 2002
    Messages:
    157
    Likes Received:
    0
    Trophy Points:
    0
    One more stupid question: Since I'm running 60W in parallel to the HF and LF inputs, is that the same/better/worse than running 120W in a non bi-amped configuration??


    Thanks
     
  9. John Dunlap

    John Dunlap Stunt Coordinator

    Joined:
    May 8, 2002
    Messages:
    157
    Likes Received:
    0
    Trophy Points:
    0
    To anyone who's interested I contacted Rotel and found out that the downside to bridging is that the damping factor is cut in half which could result in a loss of low frequency performance.
     
  10. Kevin. W

    Kevin. W Screenwriter

    Joined:
    Oct 27, 1999
    Messages:
    1,534
    Likes Received:
    0
    Trophy Points:
    0
    From what I've read it takes more than the damping factor of the amp to effect the overall sound coming out of the speaker. Checkout
    http://www.eatel.net/~amptech/elecdisc/dampfact.htm
    for info and a damping factor calculator. As from what I've read DF of 30+ is enough for home audio sound systems. Then again I maybe wrong.
    Kevin
     
  11. Craig_Kg

    Craig_Kg Supporting Actor

    Joined:
    Feb 25, 2002
    Messages:
    768
    Likes Received:
    0
    Trophy Points:
    0
    The effect of a low damping factor is loss of control of the speaker cone due to back EMF. This tends to be more prevalent at low frequencies due to the lower impedance of most speakers at lower frequencies.
     
  12. Kevin. W

    Kevin. W Screenwriter

    Joined:
    Oct 27, 1999
    Messages:
    1,534
    Likes Received:
    0
    Trophy Points:
    0
    So what is a good damping factor?

    Rotel RMB-1066: 150(20-20 8ohm)
    Bryston 6B: Over 500 at 20Hz. ref. 8 ohms
    Parasound HCA-2205: > 1000 at 20 Hz
    Anthem MCA 5: 130 @1Khz 8ohm

    From these specs I get the feeling the Bryston, Parasound, are publishing a number that makes their amps look good(high damping factor) yet its taken at the beginning of the amps frequency range. Anthem at least specs theirs at a fixed point. Yet the Rotel specs if for its full range. What gives with the numbers corresponding to frequency range. Thanks

    Kevin
     
  13. John Dunlap

    John Dunlap Stunt Coordinator

    Joined:
    May 8, 2002
    Messages:
    157
    Likes Received:
    0
    Trophy Points:
    0
    Kevin,

    I'm guessing that they do that because the heaviest demands are at the lower end of the frequency range, therefore 20hz represents a "worst case" (???)

    By the way I tried my 1066 in bridged mode last night. I was'nt able to crank it due to the wife and kids but I certainly was not able to hear any adverse effects of bridging. Definitely gained some nice headroom though!!!

    I think this is a great amp for the $$. Even at 60 WPC it produces plenty of clean power for my ears!
     
  14. Craig_Kg

    Craig_Kg Supporting Actor

    Joined:
    Feb 25, 2002
    Messages:
    768
    Likes Received:
    0
    Trophy Points:
    0
    As the FAQ states, the damping factor is the ratio between the amplifiers output impedance and the load (speaker) impedance (assumed to be 8 ohms unless stated otherwise). Most amps don't vary much in their output impedance.

    I've heard that anything better than 50 was adequate for good speaker control BUT the factor has to take into account the speaker cable and actual speaker impedances.
    ie if an amp had a DF of 130 for 8 ohms but the lowest real speaker impedance was 5.5 ohms and the cable impedance at that frequency was 0.05 ohms, then the actual worst damping factor for this combination would be 49.3.
     

Share This Page