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Rodgers 755 Speaker Relocation & Repair

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    #16
    Would it be good to put 2 FR1.7s on each main channel, and both SW7.5s on the Low / Bass channel ? It has the internal 100 watt amps for the main system. Or is that too much load on the amps ? The cabinets are 8 ohms, so that will be a 4 ohm load on each amp.
    Attached Files
    Regards, Larry

    At Home : Yamaha Electones : EX-42 ( X 3 ! ), E-5AR ( X 2, 1 parts, 1 not ), D80 ( parts ), FX-1, FX-20, HS-7T ( parts ), EL-25 ( X 2, 1 chopped, 1 not ). Allen organs : T12-A, T-12B, ADC-6000D. Baldwin 626. Hammond Concorde. Lowrey CH32-1. A bunch of Synthesizers and Keyboards. At Churches I play for : Allen Q325 ( with VISTA ), Hammond A105, Baldwin 720T, Several small and medium size pipe organs of many sorts and builders.

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      #17
      You are safe with a 4 Ohm load on the amplifier channels. Whether or not two cabinets helps depends a lot upon the placement and acoustics.

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        #18
        Another update and a few more questions. As with all jobs when dealing with churches, everything is proceeding, but quite slowly.

        This church holds about 200 people, and about 250 when really packed ( but that is very rare ). An average service has about 80 - 90 people. The main speakers will be on the rear shelf up above the windows, which is really a great place to put speakers in a church of that design in my experience. So with that in mind, this is what I think I will recommend to them :

        For the two main organ channels, two FR 1.7 speakers on each channel up on the shelf above the windows.

        For the low / bass / pedal channel, one SW 7.5 on the floor of the balcony. Or, two SW 7.5 on the floor of the balcony.

        Leave the existing Antiphonal speakers in the front of the room that are mounted up high on the side of the roof beams, facing back towards the congregation. I have not been up there to inspect these, but I think they may be Walker cabinets. And run by that mystery WM amp mentioned earlier.

        Of course, moving the cabinets over to the church and hooking them up is the only real way to tell for sure if this setup will sound good. In my shop the system as outlined sounds very nice, but my shop is very small compared to this room. My main experience in large rooms is with Allen cabinets, and to my way of thinking this setup may not have enough driver area on the main channels ? Allen cabinets have 15" drivers on the main channels, where these FR 1.7s only have 8" drivers. With the 755 internal Main / Low signal routing this might not be an issue, because the SW cabinets are likely doing the low end of the manual stops anyhow ?

        If I would go with the two SW 7.5s, do you think the built in 100 watt amp would be enough ? Or should that signal be split before the amp and each SW have it's own 100 watt amp ? One on the existing internal, and one on an additional amp ?

        I know, lots of questions here that require speculation, but the collective wisdom here is vast. Thanks for all the advice so far.
        Attached Files
        Regards, Larry

        At Home : Yamaha Electones : EX-42 ( X 3 ! ), E-5AR ( X 2, 1 parts, 1 not ), D80 ( parts ), FX-1, FX-20, HS-7T ( parts ), EL-25 ( X 2, 1 chopped, 1 not ). Allen organs : T12-A, T-12B, ADC-6000D. Baldwin 626. Hammond Concorde. Lowrey CH32-1. A bunch of Synthesizers and Keyboards. At Churches I play for : Allen Q325 ( with VISTA ), Hammond A105, Baldwin 720T, Several small and medium size pipe organs of many sorts and builders.

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          #19
          No bigger than that church is, the 100 watt amps in the console should be sufficient power, IMHO. Also, the FR1.7 speakers are pretty efficient, so they'll give you a lot of bang for the buck. I would recommend using both subs, as that's where the cone real estate is needed most.

          I know those 8" drivers in the FR1.7's seem small compared to the typical Allen 15" in an HC cabinet, but the Rodgers preamp does put the bass from all the channels into the sub channel, so the 8" speakers needn't put out much. That said, you might observe the cones when playing low manual notes on substantial stops such an 8' flute. Someone with more direct experience with this particular Rodgers model needs to chime in, but I want to say that in some models, the manual channels send out full-range speaker signals, though typical Rodgers manual cabinets of the analog era, such as the M10, would not be able to do much with the lower frequencies. However, these FR1.7's could conceivably be damaged by loud playing at low frequencies. I do think though that the notes below the 8' C will all be sent only to the pedal channel, so no risk of those getting into the FR's.
          John
          ----------
          Church: Allen MDS-45 with Allen MIDI-DIVISION-II expander
          Home: Allen Renaissance R-230 with expanded four-channel audio and MIDI-DIVISION-II
          Shop: Bunch of organs in varying conditions, some good, some not...
          Half of an incredible two-man organ service team -- servicing all the major digitals in Arkansas churches
          https://www.facebook.com/pages/Birds...97551893588434

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