# Controller Sounds?



## aeroscott (Jan 5, 2008)

I've heard that switched reluctance motors make a lot noise , unparalleled power , but controlling them is not understood by many . LTI uses them in there heavy equipment .


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## EVfun (Mar 14, 2010)

You are most likely referring to the infamous Curtis whine. It is simple to get, just lower the controller switching frequency to something in the lower to middle part of the human hearing range. The motor will act like the speaker and the controller like the amplifier. The Zilla switches at 15,700 Hz. This is near the upper limit of our hearing, and big motors make poor tweeters anyway, so the controller is nearly silent.

I guess you would have to ask the manufacturer about lowering the PWM frequency. Perhaps having it shift based on current would create a shrill acceleration effect.


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## gsmith191145 (May 1, 2011)

LithiumaniacsEVRacing said:


> As most of you know my main concern is racing EV's at the tracks. The only negative is the lack off noise, fans need to hear more than tires. I have heard some "crappy" controllers make huge buzzing sounds when they work, in racing this would be a huge plus for the crowd. How hard would it be to add sound the the "high end" controllers like the Solitons? Just picture what I am saying, first tires noise and smoke, then launch with a loud high pitch buzz, the fans would think they are watching Star Trek!


Take a chapter from Parnelli Jones. In 1967 in the STP Paxton Turbocar nicknamed "Silent Sam" They put speakers inside the car and played background noise from previous races. 

The old technology is smart and effective.


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## bonewibb (Aug 30, 2009)

I remember that, got to go to the brickyard in person.....roar, roar, roar, woosh


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## gsmith191145 (May 1, 2011)

bonewibb said:


> I remember that, got to go to the brickyard in person.....roar, roar, roar, woosh


That would be the one he he


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## PZigouras (Jun 5, 2010)

LithiumaniacsEVRacing said:


> As most of you know my main concern is racing EV's at the tracks. The only negative is the lack off noise, fans need to hear more than tires. I have heard some "crappy" controllers make huge buzzing sounds when they work, in racing this would be a huge plus for the crowd. How hard would it be to add sound the the "high end" controllers like the Solitons? Just picture what I am saying, first tires noise and smoke, then launch with a loud high pitch buzz, the fans would think they are watching Star Trek!


That's easy.. simply set your controller to 150 Hz. It'll sound like someone is being electrocuted under the hood.

The EP-1000 runs at that frequency (from the factory), and it's pretty loud with the bigger motors. Not enough to scare the fans, but still loud.


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