Calling All Nut-jobs...

[Ark Angel HFB]

http://www.beavisaudio.com/projects/DopplerBox/BeavisDopplerBox.gif

We should totally make this happen...

Just going to leave these here...

http://www.radioshack.com/family/index.jsp?categoryId=2032271
http://www.taydaelectronics.com/microphones.html
http://www.taydaelectronics.com/catalogsearch/result/?q=speaker

I'm off... make a circuit I'll happily draw a vero for anyone who needs it...

[greaser_au]

I think a piece of 300mm (1') sewer pipe about 900-1200  mm (3-4') long  would be the go. this would give a path reasonable length variation... - though the disks would  need to be totally enclosed in the pipe...

david

[Mac Walker]

This is one of the best implementations I've seen of a DIY leslie / roto speaker, especially considering the relative compact size of the unit:

http://silverysqueaks.blogspot.com/2013/02/rotary-speaker-mkii.html

Short on construction details, but it looks relatively easy to implement, sounds great to my ears....

[Seljer]

I'd reccomend PWM instead of potentiometers wired in series for the speed control of the DC motors

[newperson]

This is one of the best implementations I've seen of a DIY leslie / roto speaker, especially considering the relative compact size of the unit:

http://silverysqueaks.blogspot.com/2013/02/rotary-speaker-mkii.html

Short on construction details, but it looks relatively easy to implement, sounds great to my ears....

That sounds very nice.  I wonder how much machine noise it makes?

[PRR]

Opamp won't drive speaker with authority, use '386.

As mentioned, Butterfly valves probably make a LOT more sense. Far less leakage (specifically leak-back from main amp/speaker to mike in tube), smaller.

Small motors turn 6000RPM (100 turns per second) and I think tremolo wants to be more like 10 per second. You can't turn-down a lightly loaded motor that much. Gear-motors may be a better bet. Try robot supplies for 600RPM shaft speed. Speed can be regulated with a voltage regulator. Try 6V-12V motors with an LM317 wired to turn-down to 1.2V.

[Mark Hammer]

The dramatic quality of any rotating speaker is going to be partly a function of the radius of the rotating body that disperses the sound.  There's a few reasons for that from what I can surmise.  One is that the greater the diameter, the faster the sound is moving along the circumference; kind of like the way that the outer tracks on a vinyl disc travelled at a greater rate than the inner tracks, even though the record moved at a constant speed.  Part of the bandwidth of the Doppler effect is via the speed of movement.  You can certainly generate Doppler effects by rotating a short diameter rotating body quickly, but that will only get you bubbly sounds.  If you want a slowly rotating body to produce the Doppler cancellations, it should have as great a diameter as you can arrange for.

The second aspect is that with greater diameter, you tend to get both amplitude and timbral modulation in conjunction with the cancellations.  As the horn/rotor points away from you, there is a slight drop in treble content, as well as perceived loudness (part of which is produced by the reduction in treble, but part of which is because its pointing away from you).  When the rotating body has a short diameter, you tend not to get that.

So, in sum, there are a bazillion ways to get the sound from a speaker moving around in circles, and they will all do something of interest. I think you'll find, however, that the something they do will please you more, especially at slow speeds, if the rotor has at least an 8" radius.  Naturally, that will have implications for what is required to move the rotating body.

[J0K3RX]

Buy a fan and set it in front of your speaker.... done

[earthtonesaudio]

Or move the mic.

[Mark Hammer]

Wonderful!  But where is the regen knob?

[Lurco]

Wonderful!  But where is the regen knob?

just feed the microphoned signal back into a second input (channel) of the amp!

[Ark Angel HFB]

O_O... well I did call all the nut jobs so... I guess this is what I should have suspected

[YouAre]

I wonder if the PWM output of the TAP LFO will drive a motor.


...Tap Tempo Motor speed? 

[Jaicen_solo]

PWM To drive the motors, yes, but beware of the noise it will induce. Probably need an isolated power supply.

Secondly this will produce a tremolo effect, but I don't think it will cop the Leslie sound. I don't see anything that will produce frequency dependant phase shifting.

[Seljer]

I wonder if the PWM output of the TAP LFO will drive a motor.


...Tap Tempo Motor speed? 

I work with variable frequency drives at university. You could probably rig up a tap temp for a leslie if you wanted