Re: Hello to everyone old and new.
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Christoph,
Please sit in front of your stereo speakers and listen to something with bass,?maybe in mono.? ?Then reverse the polarity of one of the speaker connections.? ?In one case the bass will appear to come from the middle of your head (in phase), and in the other case (out of phase), the sound will be all wrong.? So for low frequencies the phase of the woofers is quite important and Uwe's question is quite relevant.? ?(otherwise why would it be important to wire one's speakers with the correct polarity)? (the wavelength in air of a 100Hz sound is around 3.5 meters).? It is the interference here that is important, not the exact phase of a single signal.
Sorry to sound pedantic.?
One of these days I will get to working on the 3 tonewheel organs and leslie in my house (C3, Cv and M100, and 142 leslie (i think, missing its label)).? They I will be around with all sorts of sophomoric questions for the group!
-Hugh
The human ear cannot hear the phase. It only can hear a phase change. If you enter the root with the Leslie spinning, you cannot say, whether is in phase or out of phase. Also the phase is frequency dependent on your position in the room.
Either is out of phase, you cannot say this or that is "out of phase".
In my remark to Uwe below, I was referring to the situation in a single Leslie in which you flip the wires going e.g. to the treble driver. And Uwes statement about "notches" in the range near the takeover frequency was what I was putting into doubt.
-- Christoph
Am 01.01.2025 um 18:10 schrieb Dennis Wage (N9OQ) < dwage@...>:
I witnessed it with my own ears. I put a sine wave tone at 600-700hz with the motors stopped and then physically reversed or flipped the phase of one of the drivers. It very easy to tell which way was in phase and which way was out of phase.?
Now, how much this affects the overall sound of the Leslie when motors are going fast and slow is debatable.? Uwe,
I believe you are wrong in your claim, that "out of phase connection of both drivers will result in a considerable notch in overall frequency response in the xover frequency region".
This is a nebulous statement lacking any mathematical or scientific substance.?
-- Christoph
You're absolutely right regarding the AC thing. But an out of phase connection of both drivers will result in a considerable notch in the overall frequency response in the xover frequency region. And, similar to a stereophonic setup, two Leslie's need to be connected in phase to get proper sound. ? Best regards!
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