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Allen MDS Voicing Controls

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  • Allen MDS Voicing Controls

    I am looking for information on the voicing controls for the Allen MDS series. Our church owns an MDS-35, and is acquiring an MDS-60. We plan to move the MDS-35 to the choir room after installing the MDS-60 in the auditorium, and I'm thinking the voicing of both may need a bit of tweaking. We may hire a technician to do the MDS-60, but I am thinking of attempting the adjustments on the MDS-35 myself.

    I am familiar with the volume controls for the four channels of our MDS-35. I've looked inside the case and have located the screwdriver controls for the voicing, but don't know how to use them. I have searched around a bit on the forum and have seen a little bit on voicing procedures, but not a good explanation about what the five letters mean (other than W for Wind).

    Can someone point me to a thread or perhaps provide some info on these controls for me?

    Thanks in advance,


  • #2
    Here's the control layout. G=Gain, M=Mid, B=Bass, T=Treble, W=Wind
    Also found a text on voicing MDS but not specifically for the 35.

    MDS35-voice_controls.pdf Voicing MDS.txt
    Servicing electronic organs since 1969.


    • #3
      Seems like we had a very extensive discussion of MDS voicing just a few weeks ago, but I can't locate it by a search. Don't know where it went!

      Anyway, the MDS-35 is a very simple model with a single W-4 cage having four primary stop groups plus two more groups just for the alterables (card reader).

      Each group has its own controls for adjusting that group of stops. Channels 1 through 4 are adjusted on top of the cage, and each channel has the following controls:

      G - gain - adjusts the volume of the stop group
      M - midrange - as name implies, adjusts the mid-frequency output of the stops in the group
      T - treble - adjusts the high frequency content of the stops in the group
      B - bass - adjusts the low frequency content of stops in the group
      W - "wind" - which is air noise and attack sound applied to one or two of the stops in that group (see chart for details)

      (Channels 5 & 6 are for the alterables and do not have "wind" controls. I won't get into those, as you should be able to extrapolate from the info given here.)

      You should find in the console a chart which shows exactly which stops are in each group. Unless there are known imbalances among the stops, you may not need to do anything, but then again you might be able to make it sound better by tinkering with it. And it's always a good idea to "exercise" the pots in an organ of that age to prevent or cure intermittent stop outages and distortion.

      Start with both great and swell expression pedals wide open (crescendo pedal NOT engaged, of course). Set the amplifier volume knobs to "8". No particular reason for that, but it allows you some degree of overall adjustment if you get through and find that it is all too loud or too soft. Make sure the speakers are suitably located, preferably all about the same distance from your ears as you sit at the console.

      In general, most of the controls should be approximately centered in their travel. That will normally give you a neutral tone that applies little artificial coloration to the stored samples. So use that as a starting point and go from there.

      However, set all the WIND controls at minimum while you are doing your voicing so that the noise will not interfere with your judgments about volume levels.

      Begin by finding the channel that has the Great 8' diapason or principal. Set the GAIN control to produce a volume level that seems about right for a single pipe stop and tweak the treble a bit if you feel the need. Then go the channel with the great octave 4. Adjust those controls likewise and make that stop just slightly softer than the 8' principal. That channel may also have the mixture in it, and if so, adjust the treble as needed to make the mixture sound right.

      Next, find the channel with the Swell 4' principal and adjust the gain on that channel to match the great octave 4. Finally, adjust the other swell channel so that the viola and the viola celeste are about equal in volume and tone. Regulate treble, and possibly midrange, as needed to produce pleasant tone color on all the stops. Any channel with a mixture in it will need attention to the treble.

      You now have your balances about right. Find the channel or channels with 16' pedal stops and adjust the bass controls on those channels to give adequate bass output and to produce the correct relationships among the various 16' stops. Be sure to listen carefully to the 32' pedal stop. You don't want it to overload the speaker or to distort the amplifier output, but you want it to produce the desired effect in the room.

      After doing all that, check your chart to see which stop or stops in each channel have "wind" and draw each one in turn, adjusting the W control to give a tasteful amount of air noise without making it sound artificial. that is a matter of taste and opinion, of course, thus the adjustment!

      That's a simplified version of the process, but it should get you in the ballpark. The midrange controls rarely need to be anywhere but centered, and if you do change them you'll notice that they rather drastically affect the overall volume of the channel, so you may need to re-visit the Gain setting on that channel as well.

      The MDS-60 is of course a much larger organ with two cages, the stops divided into eight groups. A great deal of experience and skill are required to get the voicing right on such a large and complex organ, so I do recommend professional installation. Of course, it is in reality just more of the same and with care a person can do a good voicing. You just have a lot more judgments to make as to the relationship among various stop levels.

      Good luck!
      *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!


      • #4
        John and Dave, thanks so much for your detailed and helpful replies. This is exactly the information I was looking for.