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Rotary speed question


bwood301

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The original 122 and 147 leslies rotated at around 400 RPMs for the fast speed and around 40 RPMs for the slow or chorale speed.  Can anyone relate those to the FastRate and SlowRate parameters of the rotary effect in the DSP?  For example what SlowRate setting would approximate 40 RPMs? Likewise for the FastRate setting.

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[Pedantic rant]

 

RPM stands for Rotations or Revolutions Per Minute, so you don't need to have an "s" in the abbreviation as it's already accounted for. It's just RPM. In other words, saying or writing "RPMs" would be like saying "MPHs" or "KPHs"

 

[/Pedantic rant]

 

Sorry, that is one of the things that bugs the engineer in me.  :D  :ph34r:

 

To add to this discussion, I wonder if it would be worth the time for someone to count the apparent cycles of the rotary effect. You could listen while it's on slow and see how many peaks you hear per minute, and also try to do that for the fast speed though that might be difficult.

 

Personally, if I really care about the accuracy of the rotary effect that much, I'm just going to use my GSi Burn.  :P

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Point taken Joe.

I agree that a Leslie sim box is a better choice.

For kicks I put a digital scope on the output of the PX. I found the SlowRate setting of 30 is close to 40 RPM. The max setting of 127 is about 240 RPM. On the FastRate a setting of 69 is close to 400 RPM. The max setting of 127 is about 950 RPM. I tried using a spectrum analyzer but couldn't get it to scan correctly. Probably operator error.

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Joe - Must be the engineer in me :P

 

I'm using 30 for the Slow Rate and 100 for the Fast Rate (approx. 650 RPM).  A real Hammond player would probably shoot me.  The Rotary effect "beats" against the organ tone so it's probably a matter of personal taste.  I used a sin wave tone to generate the data so I could see it easier on the scope.  I've attached a table of what I found.  I'm sure the numbers are a little off because I believe they should fit some kind of curve.

 

I'm going to buy the GSI Burn or the Ventilator II soon so it's probably moot for me.  I'll start a new thread to see which one the group likes with the PX and why.

 

Barry

 

Rotary Table.pdf

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  • 3 years later...

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