Want to build a Pipe Organ?

Discussion in 'The Projects Forum' started by cornflake000, Feb 19, 2011.

  1. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Hello everyone. I think this is my first post on this forum although I have been lurking in the background from time to time and have filled out my knowledge of electronics a bit... thank you.




    OK... I have an unusual project in mind and if anyone has any input, I would find it somewhere between extremely helpful to at least interesting.


    I am a pipe organ builder and am in charge of an huge organ in Salt Lake City, UT with about 6000 pipes. I have built many of the stops (pipes) as well as much of the pneumatic valve systems and electro pneumatic parts. There is one thing that this organ needs which is a stop called a 32 foot Open Flue. It is a huge set of pipes the largest of which is 36 feet high and would weigh about 700 lbs. There are 30 of these pipes which decrease in size from the biggest to about 8.5 feet high. To make a long story longer, there really isn't enough room to make these monstrous things. I just finished making another set of '32 reeds and that is about all the room there is up there. What I think I want to do is make an electrical version of this thing with very large speakers. The sound that these pipes make starts at 1 octave below the piano at 16hz so what I am talking about is basically a huge sub sonic (not literally) rumble. It basically just makes the windows shake for the effect. Sound interesting?



    What I vision are 30 small circuits each capable of producing a stable wave form that can be adjusted within a couple of Hz. but not much more for each note of this scale. The wave form would also need to be adjusted or filtered to give it a sharper edge or rounder as needed. I would simply amplify the sounds into a couple of maybe 15" drivers. I also thought that if I were to make 2 of these circuits for each note and separate the systems and drivers, that the natural acoustic effect could be astounding.

    I have made plenty of etched circuits and have played around with circuit design and rebuilt some major old stereo systems over the years but I am by no means any more than your basic novice. I have also built plenty of speakers and crossovers so I know about that side of things.



    How about it. Any of you guys have any ideas about this craziness or could point me to some interesting ways to produce some adjustable wave forms?




    Thanks!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    I'll suggest that there are two basic routes you can go:
    1) Synthesizer. You can produce an enormous variation of sounds with a synth, but most of them sound synthetic.
    2) Sample player. A sample player uses pre-recorded sounds, usually made in a studio, with allowances/adjustments for attack, sustain, decay, and various other parameters. A good sample would be used for perhaps 1/2 octave, so that the player would not have to overly "stretch" the sample, which would make it sound tinny on the high end or dull on the low end.

    If your aim is believable sound, a sample player is the way to go. Unfortunately, good sampling and playback technology is rather complex. You would save yourself a tremendous amount of time and headaches by purchasing a sample player unit, which had available good samples of organ stops.

    If you go the synth route - unfortunately, the 566 waveform generator IC has been discontinued, and so you will have one heck of a lot of work ahead of you trying to build something up from a multitude of operational amplifiers, capacitors and resistors; and that's per note that you want to play at one time.

    In order to generate a synthesized steam calliope note, you'd likely need 3 or more oscillators, one of which is generating white noise (broad-spectrum random oscillations).
     
  3. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Thanks for your reply.
    It's not really a matter of believable or not. If the sound was in a reasonably distinguishable range, to my ear there is no syntisizer or loop device that would be able to produce a "believable" sound and believe me I have heard all the electronic pipe organs made and there is nothing that can produce the sound made by an actual air driven pipe. This is coming from an accomplished pipe builder and voicing expert. At this range though, the only thing being produced is the movement of air at such a low pitch that the human ear can only distinguish it as controlled buffeting; it's more that it is felt than heard. The actual sound that the listener hears as "music" for lack of a better term, is made by all the higher sound producing pipes. Think of this as a sound effect added to the organ rather than a musical tone. This is why I believe it can be synthetically produced in this way. This effect has been done and is done often. But it's done by organ makers that charge thousands of dollars for what I believe is too simple an effect for the money. I did make a 32' reed stop of the full size mentioned in my last post which would be impossible to produce properly since the sound consists of a huge variety of overtones that make it what it is. This particular stop I want to make is almost totally devoid of overtones. The air sound or white noise is of no necessity in this case since the rest of the pipes make plenty of that and this would never, ever be used by itself. It is only an added illusion of power undergirding the rest of the instrument when at full volume.
    I still think it's doable. There was an electronic organ made back in the '60's that produced such a sound using simple oscillator coils of some sort. I only remember this from having repaired these instruments many years ago. They worked!
    I noticed an error I made is my first post. The whole stop is 30 notes but the only sounds I need to produce are the lowest 12. The rest are a coupling of another set of pipes connected an octave lower. All I need to make are 12 from 16Hz to around 30Hz in a pretty round wave form.
     
  4. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Generating the tones is one thing.
    You will need to amplify the tones and feed them to a large speaker.
    The sub woofer amplifier that is needed must be quite powerfull.
    The volume you need will be quite large, as the other pipes will produce quite a sound already.

    Bertus
     
  5. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Yes, you are right. The cathedral is quite large say 40M high 30M wide and 90M long. It has a reverberation of 6 seconds. It's all hard stone and wooden seating. You can almost hear a pin drop form one end to the other. With acoustics like that you would be surprised how little amplification it would take to fill it. A person has no problem talking to someone from end to end. Padding is what destroys acoustics. Height and length make a natural amplifier. Sure there will need to be some strong amps and large drivers but not as much as you might think. If the building was 1/4 the size, square, with padded seats, the organ at full volume would sound like a kazoo and you would need drivers several times as powerful to push the dead air.
     
  6. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    What an absolutely cool job! I would love to get my hands on one o' them puppies! Amazing technology for the time...(or even for now!)

    Eric
     
  7. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Here's my baby! Just to the right of middle, you will see a guy sitting on top of the organ gallery. That's me.

    [​IMG]

    Enough off topic. Are there any ideas using a self wound oscillator that might come to mind? I have wound many home made electromagnets and solenoids so I am familiar with that tedium... or adjustable wave simulators that could be monkeyed with? I'm a brain stormer. Nothing is too stupid to try out. I've come up with some pretty useful things just by brain storming and experiment.
     
  8. SgtWookie

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    Jul 17, 2007
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  9. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Ha... great! I will look these over closely. I'm sure I'll have some tech questions...

    Thanks for the leads!
     
  10. bribri

    Member

    Feb 20, 2011
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    a bit of distortion! something like a 'big muff' circuit can do wonders, gives the feeling of standing in a wind-tunnel even at low volumes. i guess it's a bit of squaring off your sinetones in an aesthetic way which does this..

    i think that some sine-wave oscillators can be fairly simple since they just need to reproduce a fixed frequency. i'm not sure if the simplest designs need temperature compensation to be reliable...probably

    there is some kind of sub-bass speaker system i've seen which has no speaker cones, it's just a big wooden box with and speaker sized hole and some kind of spinning armature inside. some p.a. company guys i know had them. they tested them at an outdoor music festival and the soundbooth wasn't even far away enough to hear/feel the effect. meanwhile the concession stand people way further back were having a hell of a bass assault.

    but...
    can't you just use a 36' pipe curved in the middle so that it's only 18' long..? i think i've seen an old theatre/movie organ which does this... or you mean you really don't have room for that?
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    After poking around a bit more on the analog synth site, you could probably save yourself lots of time by going with this synth version for the VCO:
    http://www.musicfromouterspace.com/analogsynth/VCO20090724REV0/VCO20090724REV0.html

    They offer a PCB and tempco for $25, which will help keep your frequencies more stable, and I certainly like the opamps that they used much better. There are rather complete adjustment procedures provided as well.
     
  12. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    All interesting ideas. Temperature compensation is something I have thought about. Could that be thermistor controlled/monitored basically?

    As far as mitering the pipes... with resonators (pipes) of that size and made of wood the stock itself has to be quite thick. You can take 45deg angles one at a time for up to 180deg maximum. But the largest has about an 18" square ID with the wood being 1 1/2" thick so a 21" OD at 36 or so feet high. If it were mitered to 180deg that one pipe would take up about 21" x 44" at the base. There is plenty of vertical space but even with a 21" square base plus relief, there just isn't enough floor space for these monsters. I used that up with the last set I made. Oops.
     
  13. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    I'll look that over as well. The links you sent earlier look like they are going the direction I had imagined. I think we're on the right track.
     
  14. SgtWookie

    Expert

    Jul 17, 2007
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    Yes, that's what it's about; keeping the output frequencies as stable as possible. You really don't want to have to re-tune it very often, if at all.

    You'll need to take care to use the recommended components, and buy them from manufacturer authorized distributors such as Mouser.com, Digikey.com, Allied.com, AvnetExpress.com, or order them directly from manufacturers, as counterfeit components are becoming to be a large problem. You don't want to try to save a few dollars and then spend weeks trying to figure out why it won't work.

    If you have not assembled electronic kits before, you really should try out a few before attempting something like this project. Poor soldering technique alone will very likely kill a project like this.
     
  15. Audioguru

    New Member

    Dec 20, 2007
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    The church with a reverb time of 6 seconds has terrible acoustics!
    It will be full of a mumbo-jumbo of echoes.

    The reverb will cause standing waves where some frequencies are boosted and other frequencies are cancelled.

    I heard about a church that was made with a 16Hz organ stop which shattered the church to pieces.
     
  16. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    I didn't say echo, I said reverberation. Those are 2 very different things in building acoustics. Echo=bad, Reverb=good. If the sound moves through the building in one single return from most points, that's good. If the sound continues to rebound over and over, that's echo and bad.

    Shattering? Sounds good to me!
     
    Last edited: Feb 20, 2011
  17. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    Thanks for the input. I have quite a bit of soldering experience and have etched and designed many of my own circuit boards. I recently rebuilt a 1972 Sansui QRX 7001 completely. 207 caps, about 30 TRs, and a lot of light replacements. I had to redesign and etch a new power safety switch board that was completely trashed. It was a big project and it sounds great with the modern components and even a few mods for increased separation. It's my main machine!
     
  18. SgtWookie

    Expert

    Jul 17, 2007
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    OK, then this project should be no sweat for you. :) I have to give some cautionary statements, as although it's a certainty you're extremely proficient in wind-powered instruments, it could have been that your electronics knowledge was limited. We quite often have raw beginners come on here that have no experience with circuits, yet wish to make something rather complex. I try to steer them to reasonably easy projects for starters, which increases their possibility for success with their larger project later on.

    One item I'm not too keen about with this last VCO is the lack of supply decoupling/bypass caps on the ICs. Even though the opamps have pretty decent rejection of power supply variations, I would still add 0.1uF ceramic or metal poly film and perhaps some 1uF or larger alum electrolytics near the IC's; the 0.1uF's could be added to the bottom side of the board, right across the traces.
     
  19. cornflake000

    Thread Starter New Member

    Aug 16, 2010
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    I absolutely understand the concern. And I know from my first experiences with electronics the pitfalls. Thanks for the concern. Now, I don't want to give the impression that my electronics theory and application is any more than novice but give me a soldering iron, some muriatic acid and some peroxide and I can remake the Mona Lisa ;).

    Now I'll show my lack of knowledge, the idea of those caps is to make sure that under fluctuating conditions the flow keeps going in the correct direction and that it stabilizes the flow as much as possible, is that correct?
     
  20. SgtWookie

    Expert

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    That's pretty much it. Long traces on boards act like inductors, and so resist changes in the flow of current. Supply rail bypass capacitors serve to even out the current flow vs demand, and help a great deal to keep circuits free of noise.
     
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