RE: [Harp-L] Modulation effects

[Buck Worley <boogalloo@xxxxxxx>]

Even Leo used the term "vibrato" incorrectly in some of the old amps for what is truly a tremolo circuit. He even called the guitar whammy bar 'tremolo'.
 
Vibrato is true pitch-bending. None of the early Fenders had vibrato. Even the Vibrosonic (note the spelling) had a tremolo circuit using two twin triode (7025) tubes resulting in volume fluctuation which is tremolo and not vibrato.
 
Tremolo is amplitude modulation causing a fluctuation in volume using the pre-amp tubes. The early tweeds that were cathode biased used a method of connecting one 12ax7 (oscillator) to the cathode bias of the paraphase inverter tube (another 12ax7). The third method Leo designed used a photoresistor circuit along with the tube oscillation.
 
In 1967 Leo came out with the Vibratone (note the spelling) which employed a rotating baffle (instead of a rotating horn or speaker)  that produced a true Doppler effect. It is noteworthy that CBS owned the Leslie patents at the time. Leo's design was much more "gig friendly" than most Leslies that have a two-way speaker system with no pre-amp and have to be miced in two places while the Vibratone was a single unit and only requires one mic, assuming that the player is micing through the PA. 
 
I agree with what fmj wrote below; that Leslie is a different thing producing a Doppler effect.
 
However, as stated above, vibrato and tremolo are not interchangeable even though Leo himself tried to pass it off as such.
 
Robert and fmj know what they are talking about and I love harmonica with a good Leslie effect. I first heard harp through a Leslie in the '70s when Kim Wilson was lugging a real Leslie around along with two tweed Bassmans. What a great sound, but too much equipment for me to haul and I do not recall Kim having a rodie at the time.
 
BW
 
 

> Date: Tue, 21 Jun 2011 21:02:13 -0700
> From: bad_hat@xxxxxxxx
> To: harp-l@xxxxxxxxxx
> Subject: Re: [Harp-L] Modulation effects
> 
> On 6/21/11 5:49 PM, Robert Hale wrote:
> > Vibrato and Leslie sounds ARE cool for harp because they are pitch
> > changes of the whole signal.
> 
> 
> Depends on who's defining vibrato. Vibrato and tremolo are 
> interchangeable depending upon whom you're talking to and Leslie 
> speakers are both frequency modulation and amplitude modulation. You 
> get the Doppler sound off of the rotating tweeter but the woofer has a 
> rotating baffle which modulates the volume. Any good Leslie effect 
> needs to do both. fjm