This is topic Noise in sound coming from sound drum in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Dave Ganoe (Member # 53) on 07-15-2002, 09:43 AM:
I've been helping out at a drive-in that is using eprad soundheads, two projector system. On the one machine there is this sh sh sh noise in the background of the soundtrack of any movie that is played. If you stop the sound drum from turing the noise goes away. We put a new phototube on, checked all wire connections and exciter alignment and it is all ok. Anyone have any clues? Thanks.
Posted by Bruce McGee (Member # 131) on 07-15-2002, 10:40 AM:
Sounds to me like your sound drum might be a tad out-of-round. I've had projectors over the years that had wear on the drum that caused the film to move slightly in and out of the prime focus area. Just a thought.
Bruce
Posted by Randy Stankey (Member # 64) on 07-15-2002, 04:04 PM:
Check the bearings to make sure they spin true and freely.
Any resistance to the rotation of the drum or any variation in its rotation wil cause problems in the sound. Furthermore any vibration that bad bearings cause can be transmitted through to the cell and be picked up in the sound.
Posted by Richard Hamilton (Member # 321) on 07-15-2002, 04:08 PM:
Dave,
I believe that the sound drum on that machine has a rubber sleeve on it. If you look closely, there is a seam running horizontaly across the sound drum. The seam on that sleeve probably started to separate and peel away from the sound drum causing your "sh sh sh " noise. Rick
Posted by John Eickhof (Member # 323) on 07-18-2002, 12:33 AM:
Your problrm most likely lies in the lateral guide roller, it has worn out of spec. Try and locate a replacement guide roller assy. This should cure the problem. I have had this problem on many occaisions with the SH-1000 and XL simplex soundheads, especially when they have been upgraded to LEDs or Jax Lites, the lateral guide assy gets slightly bent out of alignment during use and the roller sidetracks the film as it is running, thus the run-out causes the film to shift sideways just enough to cause a 'shoop shoop' sound I am not familiar with the Eprad soundhead, but I would suppose it is not of very high
quality construction thus parts may be easily damaged... Good luck!!------------------
John Eickhof President, Chief Slave
Northwest Theatre Equipment Co., Inc.
P.O.Box 258
Wendell, ID. 83355-0258
208-536-5489
email: jeickhof@nteequip.com
Posted by Paul G. Thompson (Member # 655) on 07-18-2002, 01:34 AM:
Get rid of that damn thing! It is a POS, like most Eprad sound heads were. You are far better off with a Simplex SH 10** that is 60 years old!
Posted by Gordon McLeod (Member # 33) on 07-19-2002, 01:49 PM:
I have several people with Star soundhead and they have no problems.
They were clever and the whiffle tree damper would probably be a solution to the damper on the christie
There are many far worse soundheads out there the Ballantyne 6 comes to mind reel fast
Posted by Dave Ganoe (Member # 53) on 07-20-2002, 12:44 AM:
UPDATE: The noise was caused by the bearings. Changed them and no more sh sh noise in the soundtrack. Thanks for all the advice.
Posted by Gerard S. Cohen (Member # 994) on 07-20-2002, 01:40 PM:
And thanks for your update!
All's well that ends well.