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Re: [ARSCLIST] Rumble when recording cylinders
I'm not an expert on this, but here are a few observations we've made from
playing back a considerable number of celluloid cylinders on an
Archeophone. The Archeophone itself has rumble, which seems to be in the
neighborhood of 30Hz. The rumble filter on our preamp takes care of this.
Celluloid cylinders also have a lot of surface deformations that manifest
as rumble, mostly in the neighborhood of 165Hz. I don't think this is due
to eccentricity of the cylinders, but the uneven surface of the celluloid.
While most of these cylinders are in excellent condition, 90 years of aging
might have contributed to an irregular surface as the celluloid and the
plaster shrink. I have no idea if the surfaces were more perfect when new
or if this was always a problem. I don't find this problem on wax
cylinders. I've also never noticed this rumble on an acoustic phonograph
because the frequency response is so poor.
Unfortunately, 165Hz seems to be near the lowest frequencies that were
captured by the recording technology, but we use a high pass filter to
eliminate as much of the rumble as we can.
Stylus selection also makes a huge difference in how much rumble comes
through, I think because of differences in the compliance of the cantilever.
David Seubert
UCSB
At 03:13 PM 4/15/2004 +0000, you wrote:
Howdie...
I am using an ACT/2 reproducer which many have told me produces good
results. <http://nipperhead.com/act/>http://nipperhead.com/act/ I have a
custom built prototype phonograph machine
<http://hertz.onlinepeople.net:801/phonograph/>http://hertz.onlinepeople.net:801/phonograph/
that uses a very quiet ac servo motor and an edison home 2/4 minute top
works.
The top works is very stable and concentric. When observing the mandrel
it is rock steady at any speed from 30 RPM through 240 RPM. However, when
I place a cylinder on the mandrel, the cylinders have their own slight
eccentricity (even my best condition cylinders have some slight
eccentricity). This ever so slight abberation in the cylinder seems to be
causing really bad rumble on the recordings. I mean really bad! And the
rumble that I am getting is a direct function of the eccentricity of the
cylinder. It is not any noise being transmitted from any part of the
mechanical train.
So here are my questions:
1. For cylinders that are vertically cut, and considering the eccentricity
is also vertical in orientation, is it ever possible to isolate and
eliminate rumble? (other than using filters at the rumble frequency or
other digital rumble filters that still seem to leave plenty of rumble
--I've tried a few such as sound laundry).
2. Anyone have experience with the ACT/2 reproducer? I am assuming it is
rewired for vertical cut grooves, but haven't been able to get in touch
with the guy I bought it from.
3. What do people on this list do in this situation? Some of you have
archeophones. While I know there are adjustments for eccentricity, I find
that the ends of the cylinders typically problematic but the centers (ie 2
minutes into a 4 minute cyl) seem much quieter in this regard. So for
archeophone users do you have rumble problems?
If anyone is interested, I could probably post a sample audio file with
the rumble present, but it is a lot!
Thanks in advance
Eugene