• RE: MY Open Baffle Dipole Sub Results - MarcL 12:28:24 11/10/24 (3)
  In Reply to: RE: MY Open Baffle Dipole Sub Results posted by josh358 on November 10, 2024 at 12:13:15

  I measured a clear difference in the impulse response with and without the servo and between the three damping settings. But I had to use a different amp to test without servo because there is no way to defeat the servo in the Rythmik amp ... there are three settings but you can't run the amp with servo disconnected. And then I had to do the shelf filter with a miniDSP for the other amp because the shelf filters are built into the servo amp too.
  
  Did I try to HEAR a difference? No ... I did not attempt to do that to my brain given that you can't just switch it off and rewiring everything would kill off any sonic memory. But a couple weeks ago I heard a sealed sub built by someone who designs and builds speakers. He made his with two 15" drivers and the Rythnik servo amp and it has the same signature sound that I hear. And that guy said he felt the servo made a big difference.
  Agilist, Musician, Photographer, Audiophile
  Magneplanar: 3.7, CCR, MC1,LRS, MMGW, DWM; Outlaw: UltraX12, LFM-1C; Emotiva: XMC-2; Nord: Nord One NC500DM, Nord Three 1ET7040SA; Outlaw: Model 7500; OPPO 205
  
  

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  • RE: MY Open Baffle Dipole Sub Results - emailtim 18:51:23 11/11/24 (2)
    In Reply to: RE: MY Open Baffle Dipole Sub Results posted by MarcL on November 10, 2024 at 12:28:24

    FWIW, when I did my test, I compared the Rythmik servo amp against B&O IcePower 1000ASP amps. "Better" amps may perform better than the amps I tested.

    The 1000ASP amp measured better (REW) with faster dampening/setting than the servo amp using 2 drivers per side (no change in speaker, nor mic positions, just swapping amp feeds). That being said, I did not hear a difference.

    I did not try this test with 3 drivers per side. The 1000ASP amp is stable to lower Ohm loads and has more power than the Rhythmik amp so I would assume 3 or 4 drivers per side would follow suit.

    I used my own FIR dipole compensation filters. The dipole compensation filters in the Rythmik amp can't be defeated without a special control board from Brian D. Same goes for most all of the controls in the plate amp.

    I spoke with Brian D about using the IcePower amps when they first came out. He said he tried to negotiate a deal with the OEM, but they would not add the hooks he needed to make it a servo unit. If they did, the resulting servo would probably benefit from a stronger amp.

    For a while, Brian did have servo amps using a different amplifier, then they were discontinued. I haven't followed the progression since then.

    Brian confirmed he made some one-size-fits-all engineering decisions for the servo amp. He also confirmed that those one-size-fits-all decisions may not be optimal for every application ( by definition ).

    I bought a special board from him to get around this problem and in the end, decided to do all of my configurations in one place instead of playing dueling banjos in case a physical control accidentally got changed. Another dueling banjo was the upstream filters undoing unwanted changes in the plate amp filters (shortest distance between 2 points is a straight line, instead of tacking).

    It also removed another layer of filters and circuitry from the signal chain while allowing more sub amp options. Sold off the plate amps.

    Since the H-Frame cabinet has no backwall/cabinet induced waves, most all of the designs issues the servo was trying to address in a sealed cabinet does NOT exist in an OB/Dipole design.

    If memory serves, the servo amp was designed for sealed and ported boxes, not OB/Dipoles without boxes. The latter application came after the former and required some modifications for that application.

    A370PEQ Dampening Factor:

    The A370PEQ is rated at 370 watts of power into a 4 ohm load.
    Harmonic distortion is less 0.01% at 200WRMS @4ohms (-3 dB from full output).

    Damping factor: 160 @ 4ohms. (Note: damping factor is speaker wires dominated. Without speaker wires, the native damping factor is > 800).

    ICEPower 1000ASP Dampening Factor:

    1000W @ 0.01% THD+N, 100 Hz, 4 ohm

    
    .
    
    2022/03/30 Historical Records CENSORED
    

    • A370PEQ   (Open in New Window)

    
    

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    Edits: 11/11/24   11/11/24   11/11/24   11/11/24   11/11/24   11/11/24   11/11/24

    • RE: MY Open Baffle Dipole Sub Results - MarcL 06:57:57 11/13/24 (1)
      In Reply to: RE: MY Open Baffle Dipole Sub Results posted by emailtim on November 11, 2024 at 18:51:23

      Thanks for sharing this Tim. Good for others to see the perspective you have from trying different methods. After we discussed it last year I decided to do the 3-high and I figured if I start with the Rythmik amp I can get an understanding of how it works and sounds ... always the opportunity to change the method and hardware in the future, but right now I really like the result. I was a little concerned it might not be enough power compared to the rest of my system, but the Dolby Atmos thunder plays cleanly 100db @20Hz so I figure that's good!
      
      A couple weeks ago I visited a guy who built two 2'x2'x2' sealed subs with dual 15" servo drivers each and a Rythmik amp. It must have been an older amp because it had balanced inputs (which have been unavailable for a couple years) and he said it was a 500W Class D. They sounded great!
      
      
      Agilist, Musician, Photographer, Audiophile
      Magneplanar: 3.7, CCR, MC1,LRS, MMGW, DWM; Outlaw: UltraX12, LFM-1C; Emotiva: XMC-2; Nord: Nord One NC500DM, Nord Three 1ET7040SA; Outlaw: Model 7500; OPPO 205
      
      

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      • RE: MY Open Baffle Dipole Sub Results - emailtim 09:49:36 11/13/24 (0)
        In Reply to: RE: MY Open Baffle Dipole Sub Results posted by MarcL on November 13, 2024 at 06:57:57

        IIRC some of the previous amps were Hypex based.
        
        The balanced option wasn't available when I bought the A370PEQ.
        
        The A370PEQ is a great all-in-one Swiss Army Knife for those that don't have adequate FIR options upstream.
        
        I wouldn't mind 3 or 4 drivers/side either. The extra XMAS and SD help. When I tried 1, 2, 3 and 4 drivers, the performance progression was notable. I can't image those with 6/side.
        .
        
        2022/03/30 Historical Records CENSORED
        
        

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