wrv@cbnewse.ATT.COM (william.r.vogel) (12/27/89)
I am in the process of purchasing a new Galanti electronic (classical)
organ. This instrument utilizes the latest in digital sampling techniques
to reproduce digitally recorded samples of the finest organ pipes in Europe.
Because of space/monetary/logistical considerations, I am going to build
my own amplifier/speaker system. Please read on if this article interests
you.
BACKGROUND INFORMATION
The instrument produces fundamental frequencies from 16 HZ to 16K HZ,
into 16 separate output channels. These channels vary as to their
content, for example a pedal channel does indeed produce notes as low
as 16 HZ, whereas most manual channels have fundamentals at 64 HZ.
In addition, there are 8 "reed" channels, which re-produce the sounds
of reed organ pipes. This differ from flue organ pipes in that they
actually have a metal reed vibrating against a resonator to produce
the tone, whereas a flue pipe works on the basic principal of a whistle.
My experience with these types of sounds has shown me that these sounds
are often best reproduced by a horn type driver, whereas flue sounds
are best reproduced by a standard cone type driver.
The organ's output is a pre-amp level signal suitable to be directly
plugged in to a power amp. This organ company typically uses 200 wpc
Carver stereo amplifiers in their installations.
MY PLANS
Although the organ can play from as little as one channel, for the best
realism and voicing capabilities I plan to employ all sixteen channels.
Therefore, I will need 16 channels of amplification, probably from
50 to 75 watts (per channel) will be sufficient. I would like the basic
ability to adjust the following: (bass, treble, midrange, and level) for
each channel. The amplifiers would ultimately be small, and run off a
seperate power supply, so that I can have multiple amps running from the
same power supply. I am not adverse to building these myself from kits
or even on breadboards from schematics, however, the design of these
amplifiers is beyond my ability.
WHAT I NEED
1. 16 channels of amplification, preferrably with a small amount of
tone control, level control and possible a "pan" control to be able
to pan between input signals. The amps have to be cheap (hopefully
less than $1/watt) since I need 16 channels worth. Some channels
could be potentially less powerful than others, but for simplicity
I'd like to stick with one basic unit.
2. 16 channels of speaker system. There are three basic types of channels:
# TYPE FREQ. RANGE
6 flue manual 64 HZ to 16K HZ (two channels have 32HZ requirements)
6 reed manual 32 HZ to 16K HZ (four channels need only go down to 64 HZ)
2 flue pedal 16 HZ to 16K HZ
2 reed pedal 16 HZ to 16K HZ
Keep in mind that the reed channels are typically "all harmonics", i.e.
there is no real fundamental tone at the base frequency. These channels
(reeds) should ultimately be played through horn drivers, whereas the
flue channels should be cone drivers (except of course for the tweeters).
For the flue channels, I was basically thinking of using the following:
one 10" or 12" driver, one 3-6" midrange, one 1-2" tweeter, all with
appropriate crossover. For the pedal channels, I was thinking of using
the same as above, except adding a 15" bass driver to the setup.
For the reed channels I was thinking of using horn drivers, probably
10", 4" and 1", with appropriate drivers.
HOW YOU CAN HELP
I need recommendations on amplifiers, speakers and crossovers. As I said,
I have no problem building this stuff from schematics, but I couldn't
design the stuff on my own. I need to begin planning the installtion
as soon as possible, because I'll be re-modeling the 10' by 15' room
the organ console, speakers and amplifiers will live in when this
project is complete! Thanks for your interest.
-Bill Vogel
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