Re: Questions

[bpb@bpbsn.cca.rockwell.com (Brad Baker)]

Malte Rogacki writes:

  > I had noticed it before, but did not get around it too much: My
  > Hammond produces a kind of "subharmonics". These are harmonics
  > below the actual pitch. Strangely, those subharmonics are in no
  > fixed interval, on some pitches they are an octave low, on some
  > other pitches a third, on some other pitches there are no
  > subharmonics at all. The effect is less noticeable with a number
  > of drawbars pulled out, but very annoying when using just one or
  > two drawbars. Also, the effect is not equal on all drawbars. For
  > example, if I have selected just the 4" drawbar, the subharmonics
  > are extremely annoying in the lowest octave. But if I use the 8"
  > drawbar instead and play one octave higher (aka the same pitches)
  > the effect is less drastically. Any ideas?

(from an earlier posting to the list)

 >> My B-3's tone generator outputs 44-48 have audible upper
 >> harmonic components. The outputs from 37-43 have other lower
 >> frequency components. The ones with the filter cap's, 49-91,
 >> have other low/high frequency components that may or may not be
 >> audible.

these are the normal xtalk components present in a tone generator
hammonds' output. if you take them away it wont sound like a
hammond. some hammonds are worse (or better depending on how you view
it) than others wrt xtalk content. mine's got lottsa subharmonic xtalk
and i love it's sound now, but i know what you mean, at first it
bugged me a bit: "why doesn't my hammond generate pure sine waves?"
but those lower harmonics really give the sound some meat - like a
rumbling growl or something. the upper harmonics are more noticeable,
depending on what i'm playing. hammond made an effort to reduce them
on generator outputs 44-48 with some r's and c's but i've heard
there's some question as to the effectiveness of the modifications
they made. jerry welch (organ service co inc) said hammond tried to
group certain tone generator outputs together to control this
somewhat.

as to why the level of the xtalk varies with different drawbar
settings but the same tone generator note produced - i'm clueless.
mine doesn't seem to do that. if i configure the drawbars so that one
tone is produced, the xtalk sounds the same regardless of which
drawbar is pulled or note that is played. maybe some of the xtalk is
occuring in the manual assembly instead of the tone generator but it's
purely conjecture on my part tho.

  > Also, could someone explain how the bass pedal actually works? I
  > was under the impression that the 16" and 8" pedal drawbars mean
  > that there is actually only one pitch per note, but if I press a
  > pedal very slowly I can hear much more harmonics kick in.

a pedal plays more than one tone per drawbar. the next faq will
contain an addition to the modifications section regarding the pedal
drawbar wiring showing how to alter this arrangement.

bradley baker
bpb@mlb.cca.rockwell.com