DIYAPASON-L Digest #792 - Thursday, April 10, 2003
 
Re: Overhead pipe clearance
  by "Larry Chace" <RLC1@etnainstruments.com>
Re: [Residence Organs]  Re: Overhead pipe clearance
  by <Pipewheezr@aol.com>
Overhead pipe clearance
  by "F. Eugene (Gene) Dunnam" <dunnam@phys.ufl.edu>
Re: [Residence Organs]  Overhead pipe clearance
  by "BRIAN GRAHAM" <qax@prodigy.net>
Photos of rare Kilgen theatre organ destined for dump
  by <Wuxuzusu@aol.com>
 

(back) Subject: Re: Overhead pipe clearance From: "Larry Chace" <RLC1@etnainstruments.com> Date: Thu, 10 Apr 2003 09:48:30 -0400   Bob Taylor asked about a "low overhead" situation and its potential = effects upon his string pipes. Grabbing a handy Aeolian "String F" pipe (Viol d'Orchestre), an FF# about 6' long with a narrow tuning slot (about 3/8" wide), I conducted a terribly scientific experiment: blowing into the pipe (at constant pressure, of course!), I moved it toward a surface and back away from that surface. Even with the pipe's top against the surface, I could detect *no* difference in pitch or tone quality.   That might tend to suggest that Bob can go ahead and install the CC pipes even though the clearance is less than planned, assuming that it is physically possible to install and remove the pipes.   I'll admit that my initial reaction was that those CC pipes should be placed onto little offset toeboards that would be tubed to the chest toe holes. I anticipated both a flattening of the pitch and a reduction in = the harmonic content, but neither seems to have happened. (Aeolian's approach would have been to miter the pipes, perhaps using just a single joint so that the top-most portion is at a 45 degree angle; the CC# pipe on one of my "String F" ranks is mitered that way, and both CC pipes were given a two-joint 90 degree miter.)   A quick calculation shows that the open area of the tuning slot is about 1 square inch (3/8" wide and about 3" long). The pipe is 2" in diameter, = for a cross-sectional area of about 3 square inches. Perhaps the tuning slot is "large enough" that the top of the pipe can be completely closed = without affecting the speech.   Larry Chace        
(back) Subject: Re: [Residence Organs] Re: Overhead pipe clearance From: <Pipewheezr@aol.com> Date: Thu, 10 Apr 2003 10:44:23 EDT     --part1_a4.360e58ab.2bc6dd47_boundary Content-Type: text/plain; charset=3D"US-ASCII" Content-Transfer-Encoding: 7bit   I have two cents for this. My principal 8'c is two inches from the ceiling =   but the ceiling is 45 degrees as goes by and no tuning or sounding = problems. The bottom 12 do have tuning scrolls. Straight tuners might not work, I = will try it and see what happens. I was lucky yesterday I got to work on the organ all day, today (sigh) = back to work. Dennis   --part1_a4.360e58ab.2bc6dd47_boundary Content-Type: text/html; charset=3D"US-ASCII" Content-Transfer-Encoding: quoted-printable   <HTML><FONT FACE=3D3Darial,helvetica><FONT SIZE=3D3D3 = FAMILY=3D3D"SANSSERIF" FACE=3D =3D3D"Arial" LANG=3D3D"0">I have two cents for this. My principal 8'c is = two inc=3D hes from the ceiling but the ceiling is 45 degrees as goes by and no = tuning=3D20=3D or sounding problems. The bottom 12 do have tuning scrolls. Straight = tuners=3D20=3D might not work, I will try it and see what happens.<BR> I was lucky yesterday I got to work on the organ all day, today (sigh) = back=3D20=3D to work.<BR> Dennis</FONT></HTML>   --part1_a4.360e58ab.2bc6dd47_boundary--  
(back) Subject: Overhead pipe clearance From: "F. Eugene (Gene) Dunnam" <dunnam@phys.ufl.edu> Date: Thu, 10 Apr 2003 11:50:11 -0400   Bob Taylor wrote:   From: "Robert W. Taylor" <rtaylor@socket.net> Date: Wed, 9 Apr 2003 21:13:56 -0500   I would like comments from the group about close overhead clearance. Through a series of errors, I now find that my swell strings, 8' CC, are very close to the ceiling. These are all straight pipes, V.D.O., Aeoline, and Salicional with tuning scrolls.   The pipes actually fit, but what had been planned to be a 5 inch ceiling clearance is now much less. If the pipes can be tuned to picth, are there any other concerns? What is the effect of close ceiling clearance?   Bob Taylor *************** I can only give you the acoustical theory, as I'm not presently set up to do an experiment. The 'end correction' for an open cylindrical pipe is approximately 0.6 R where R =3D pipe radius. What happens is that the standing wave in the pipe 'leaks' out of the open end a little; that's why an actual speaking pipe is always slightly shorter than the calculated 1/2 wavelength and a 'fat' rank tends to be a bit shorter than a skinny one.   Also, haven't many of us, in hunting for a cipher in an open rank, moved our hands over the pipe ends to try & locate the beast?   So I'd say that if your ceiling is at least 0.6 R from the pipe end you're OK, more so if there are tuning scrolls as Kelvin points out. And if the ceiling is porous [not hard & reflective] you can probably get away with closer clearance. But if there's a hard reflecting surface very close to the end it can affect the sound: reflecting part of the wave back into the air column is exactly what happens in a rohrflute.   Best wishes,   Gene   **************************************************** * F. Eugene (Gene) Dunnam * * Professor of Physics <dunnam@phys.ufl.edu> * * University of Florida (352) 392-1444 * * P. O. Box 118440 * * Gainesville, FL 32611-8440 * * <http://www.phys.ufl.edu/~dunnam/Welcome.html> * ****************************************************  
(back) Subject: Re: [Residence Organs] Overhead pipe clearance From: "BRIAN GRAHAM" <qax@prodigy.net> Date: Thu, 10 Apr 2003 14:41:30 -0700 (PDT)   --0-1299978534-1050010890=3D:84927 Content-Type: text/plain; charset=3Dus-ascii     Bob- Regarding the ceiling clearance issue:   Have you thought about how you're going to get these pipes in place in the = rackboard?   I had low clearance to a few pipes at my last house (maybe 4"), and a few = pipes were quite difficult to get into their places in the rackboard, = since you need roughly the height of the pipe plus the height of the = rackboard for clearance (actually somewhat less than this for metal pipes = since you can kind of "rotate" them into position due to the tapered = foot). With ZERO clearance some pipes may be impossible to rack.   Just a thought.   -Brian Lexington Township, Kansas   PS I just finished converting my cistern into a blower & regulator room, = so "Esther" (or at least part of her) should be singing again within a few = months.   --0-1299978534-1050010890=3D:84927 Content-Type: text/html; charset=3Dus-ascii   <P>Bob- <P>Regarding the ceiling clearance issue:</P> <P>Have you thought about how you're going to get these pipes in place in = the rackboard?</P> <P>I had low clearance to a few pipes at my last house (maybe 4"), and a = few pipes were quite difficult to get into their places in the rackboard, = since&nbsp;you need roughly the height of the pipe plus the height of the = rackboard for clearance (actually somewhat less than this for metal pipes = since you can kind of "rotate" them into position due to the tapered = foot).&nbsp; With ZERO clearance some pipes may be impossible to rack.</P> <P>Just a thought.</P> <P>-Brian<BR>Lexington Township, Kansas</P> <P>PS&nbsp; I just finished converting my cistern into a blower &amp; = regulator room, so "Esther" (or at least part of her) should&nbsp;be = singing again within a few months.</P> --0-1299978534-1050010890=3D:84927--  
(back) Subject: Photos of rare Kilgen theatre organ destined for dump From: <Wuxuzusu@aol.com> Date: Thu, 10 Apr 2003 19:55:53 -0400   Greetings all,   Follow this website for two photos of the rare 4/14 Kilgen theatre organ = that is threatened with a trip to the dumpster.   http://members.fortunecity.com/broadcastpioneers/wfil/38organ.html   http://members.fortunecity.com/broadcastpioneers/wfil/47organ.html   To purchase this organ call Kevin Collopy in Loveland, OH. 513/697-7407, = or fax him at 513/697-7201.   Musically,   Stan Krider