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A Mechanical Phase/Vibrato (Slight Return)?

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  • A Mechanical Phase/Vibrato (Slight Return)?

    I stumbled upon an accidental discovery at the shop the other day, and it's kind of amazing. Due to the heat we've had recently I had a fan going on the bench directly across the shop from me. After a repair, I propped the amp up and turned it on for a play test (Amps usually sit about 3 milk crates high for our purposes.. well, exactly 3 milk crates high). I noticed something immediately, there was this strange modulating distortion I was hearing, and thought something was wrong. It didn't sound bad, necessarily, but wasn't right either. After a moment, I realized that I was hearing the effect of the fan blades modulating the phase of the speaker sound. Kind of laughed it off and turned off the fan.
    My boss made the comment "I bet you hook it up to a variac as a speed control, and it probably sounds pretty cool". We looked at each other for a second, and grabbed what we needed for a quick experiment - positioning the fan in front of the speaker about 2 (maybe 2 1/2) ft away facing the speaker, and used the variac to slow the speed to emulate the rough speed of an LFO you typically hear in a guitar effect.
    dude, the phase shifting effect sounded so eff-ing good it's difficult to describe. As good as any I've ever heard. however, I'm sure that so much of the perceived effect was the combination of at least three factors: the position of the speaker with respect to the fan (I'll include distance and directional angle under this), the type of fan used (aluminum blades?), and my listening position with respect to the other 2. Unfortunately, it was a quick experiment as we had actual work to do. But it was enough to get exited about and do some more experimenting with.
    Here is the basic set up – as just a first time guess as to what might sound good:

    Click image for larger version  Name:	Phase Shift Fan effect.jpg Views:	0 Size:	315.2 KB ID:	935369


    If I have some time after hours at the shop, I'll try and get some sound samples.
    Low-tech and killer sounding; you heard it here first --->Soulfetish
    If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

  • #2
    Sure, why not? It's similar in principal to a Leslie cabinet with the rotating Styrofoam thingy. The only problem I see is the extra fan noise picked up by the mic.
    "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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    • #3
      Originally posted by The Dude View Post
      Sure, why not? It's similar in principal to a Leslie cabinet with the rotating Styrofoam thingy. The only problem I see is the extra fan noise picked up by the mic.
      Right! I was thinking about that as well. I wasn't paying attention at the time, but I don't remember there being much motor noise from the fan when compared to the idle amp noise, but there's also the noise of the air on the mic element that would need to be considered. Good point.
      If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

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      • #4
        Originally posted by SoulFetish;n935368 I had a fan going on the bench directly across the shop from me. After a repair, I propped the amp up and turned it on for a play test....., there was this strange modulating distortion I was hearing, and thought something was wrong. It didn't sound bad, necessarily, but wasn't right either. After a moment, I realized that I was hearing the effect of the fan blades modulating the phase of the speaker sound.
        .....

        Low-tech and killer sounding;[B
        you heard it here first[/B] --->Soulfetish
        Not so fast Sonny

        Have ben using it for fun for over 40 years now and my kids LOVED it when they were about 8 to 10 y.o.

        Thatīs nothing, Yamaha and otyhers have been using something similar for decades.

        Not a Leslie and they canīt use the name anyway, so they use "Rotatone" or something.

        Vaguely remember Roland (or Kawai or Korg?) lso had something similar
        Last edited by J M Fahey; 06-25-2021, 04:03 PM.
        Juan Manuel Fahey

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        • #5
          I did that as a kid decades ago. it amused my sister to hear me talking through the fan like a "space man". My mom said something to the effect "SO this is why you spend hours in the work shop with wires?"
          Education is what you're left with after you have forgotten what you have learned.

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          • #6
            Whoa, whoa, whoa.. we aint talkin ‘bout talking through a fan to get darth vaders voice. Everybody’s done that. This is different
            If I have a 50% chance of guessing the right answer, I guess wrong 80% of the time.

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            • #7
              I see somebody has been smoking something in the workshop again...............
              nosaj
               
              soldering stuff that's broken, breaking stuff that works, Yeah!

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