DIYAPASON-L Digest #666 - Tuesday, October 15, 2002
 
Deslotting Geigens
  by <Kzimmer0817@aol.com>
 

(back) Subject: Deslotting Geigens From: <Kzimmer0817@aol.com> Date: Tue, 15 Oct 2002 23:27:54 EDT     --part1_19e.a504e84.2ade36ba_boundary Content-Type: text/plain; charset=3D"US-ASCII" Content-Transfer-Encoding: 7bit   List,   This question may be premature since I do not yet have my organ set up and =   playing. Nevertheless, I'll post it.   My organ has an 8' Geigen Diapason as its unison diapason for the Great. There is a 4' Octave as well. I did not get an adequate enough "listen" = to these to really determine how they sounded. I was told by someone experienced in these matters that they were not really scaled well = relative to each other. The octave played an octave lower actually sounded more = like it should be the 8' Open.   A recommendation was made to deslot the geigen. I've heard mixed reviews = on this. I guess my comfusion stems from my lack of understanding of what = part the "slot" plays structurally. The speaking length of an open pipe determines the pitch. Tuning collars are often used to make fine = adjustments in the speaking length in order to tune the pipes. I understand that a = cap doubles the speaking length and lowers the pitch an octave. I assume that = a stopped pipe that is to have a stopper instead of a cap must be made a = little longer than a capped pipe in order to accomodate the thickness of the stopper.   I'm not certain where the slots fit in. These pipes are tuned either by sliding a tuning collar that fits proximal to the slots and covers up more = or less of the slot(s) as needed to effect tuning or by twisting up or down = the tongue of pipe metal from the pipe (that makes the slot) much like opening = a sardine can.   Is some portion of the slot included in the speaking length of the pipe? = I would think that it would need to be in order to have such an effect on = the timbre of the pipe.   My reason for going thru the above thinking process is that I had tho't = about cutting the pipe off below the slots and using a tuning collar to return = the pipe to its speaking length. I was told that cutting off the slots would remove much of the stringiness of the geigen.   What I didn't understand was how this would affect the "scale" of the = pipe. I was told that some shifting of pipes might be necessary to get the = scaling correct. If the slotted pipe is of a certain scale > you cut off the = slotted portion just proximal to what would be the appropriate speaking length for =   that same pitch > place a tuning collar to fine tune the pitch > how have = you changed the scale?   IOW, can you make a geigen into a plain 8' open diapason?   Thanks, Keith   --part1_19e.a504e84.2ade36ba_boundary Content-Type: text/html; charset=3D"US-ASCII" Content-Transfer-Encoding: 7bit   <HTML><FONT FACE=3Darial,helvetica><FONT SIZE=3D2 FAMILY=3D"SANSSERIF" = FACE=3D"Arial" LANG=3D"0">List,<BR> <BR> This question may be premature since I do not yet have my organ set up and = playing.&nbsp; Nevertheless, I'll post it.<BR> <BR> My organ has an 8' Geigen Diapason as its unison diapason for the = Great.&nbsp; There is a 4' Octave as well.&nbsp; I did not get an adequate = enough "listen" to these to really determine how they sounded.&nbsp; I was = told by someone experienced in these matters that they were not really = scaled well relative to each other.&nbsp; The octave played an octave = lower actually sounded more like it should be the 8' Open.<BR> <BR> A recommendation was made to deslot the geigen.&nbsp; I've heard mixed = reviews on this.&nbsp; I guess my comfusion stems from my lack of = understanding of what part the "slot" plays structurally.&nbsp; The = speaking length of an open pipe determines the pitch.&nbsp; Tuning collars = are often used to make fine adjustments in the speaking length in order to = tune the pipes.&nbsp; I understand that a cap doubles the speaking length = and lowers the pitch an octave.&nbsp; I assume that a stopped pipe that is = to have a stopper instead of a cap must be made a little longer than a = capped pipe in order to accomodate the thickness of the stopper.<BR> <BR> I'm not certain where the slots fit in.&nbsp; These pipes are tuned either = by sliding a tuning collar that fits proximal to the slots and covers up more or less of = the slot(s) as needed to effect tuning or by twisting up or down the = tongue of pipe metal from the pipe (that makes the slot) much like opening = a sardine can.<BR> <BR> Is some portion of the slot included in the speaking length of the = pipe?&nbsp; I would think that it would need to be in order to have such = an effect on the timbre of the pipe.<BR> <BR> My reason for going thru the above thinking process is that I had tho't = about cutting the pipe off below the slots and using a tuning collar to = return the pipe to its speaking length.&nbsp; I was told that cutting off = the slots would remove much of the stringiness of the geigen.<BR> <BR> What I didn't understand was how this would affect the "scale" of the = pipe.&nbsp; I was told that some shifting of pipes might be necessary to = get the scaling correct.&nbsp; If the slotted pipe is of a certain scale = &gt; you cut off the slotted portion just proximal to what would be the = appropriate speaking length for that same pitch &gt; place a tuning collar = to fine tune the pitch &gt; how have you changed the scale?<BR> <BR> IOW, can you make a geigen into a plain 8' open diapason?<BR> <BR> Thanks,<BR> Keith</FONT></HTML>   --part1_19e.a504e84.2ade36ba_boundary--