Hammond and the Leslie Speaker








One of the most recognized hallmarks of Hammond's iconic sound is the Leslie Speaker.  But Laurens Hammond was never on board with the Leslie.  Why was that?

Because it's a pre-amplified sound and you've got nine wire contacts on the back of the keys that are touching the bus bar, they ground and make a little pop, which Laurens Hammond thought was a horrible flaw.

That's why he hated the Leslie speaker so much.  Because the Leslie used a high frequency driver that literally accentuated that pop and wave.

That's also why if you look at the old standard speakers made by Hammond themselves, the last thing you would find in one of those is a high frequency driver. They used really muddled full range speakers trying to minimize that pop at the beginning of the note which of course now is what everybody loves, that key click. So it's an interesting history.

Laurens Hammond didn't just have a slight distaste for Leslie Speakers, he was admittedly opposed to them.  Could you elaborate on that?

There was a time when Laurens Hammond was still alive and controlling the company, if you sold Hammond Organs, you could not sell the Leslie speaker.  Because Laurens Hammond found the Leslie Speaker to be offensive because of the high frequency driver and accentuated the key pop, which he considered to be a flaw.  He didn't want his instruments having the pop at the beginning of the note.

So back in the day, a person would go to one store to buy their Hammond Organ, and then go someplace else to buy their Leslie Speaker, and then they would need to have a technician to install a kit so that the speaker could be used.

Hammond built their own speaker systems.  The speaker built for the B3 was called the PR-40 and the smaller version of it the PR-20.  And these had fixed speakers with no high frequency drivers, they were purely full range speakers.  So the high frequency roll-off was maybe 10k or maybe even lover than that, so it could not reproduce the pop or click.

The Leslie Speaker is a mystical magical piece of equipment.  Would you take a moment to describe the engineering of a Leslie Speaker in simple terms?

Don Leslie invented the Leslie Speaker.  You have a high frequency driver.  Some people would call it a tweeter, but it's a high frequency driver.  And it is mounted in the cabinet pointed straight up.  Above that speaker, is a horn on bearings rotating round and round being driven by a motor.  So the sound is being driven projected up from this speaker into this rotating horn which turns and has a bevel on it kind of like a trumpet.

So it's taking the sound, bending it, and then feeding it out through this horn going round and round and round.  If you look inside the Leslie Speaker, it looks like it has two horns. One of them is just there for counter balance.  So one horn is live and the other is a dummy.

This high frequency sound, everything from about 600Hz up is coming out of this rotating horn.  And it has two speeds: Coral; which is going very slowly which is a pulsating sound, of Tremelo; which kicks it up to a nice RMP that gives you a nice vibrato effect.

Let's continue to ignore the bass for a moment and just talk about the high frequency driver.  When that horn is moving, there are several things that are taking place simultaneously.

The doppler effect comes into play because of this rotation and the horn moving towards you.  As the horn is moving towards you, the pitch is actually moving up slightly.  And as it moves away, the pitch drops, just like a train whistle comes towards you the pitch gets higher and moving away the pitch drops.  So there is the doppler effect and there is also a tremolo effect because of the pulsating rotation.  And most importantly, high pitched frequencies are highly directional.  So you've got this 360º speaker squirting high frequency and mid-range sounds all around in a circle.  And as it's doing that, sounds are moving towards you and away from you, but not only that...high frequency sounds bounce off the walls.  But the bounce points are in motion too.

So now it's like a billiard table with all these sounds bouncing around in a rotational pattern.  And that's how the Leslie Speaker Fills the room with Sound.

Now that you've touched on how the high frequency driver works, what about the bass?

The woofer is pointed straight down into a wash tub sized baffle, that looks litterally like a round tub.  It's open at the top and it's got a 45º angle plate in there that's open on one side with a counter balance on the other, so that the bass hits this plate and bounces out 90º along the floor.   But that's rotating in the opposite direction.

With the bass, you get the doppler effect, but you don't get the reflections and that sort of thing as much because bass is so non-directional. That's how in these modern day speaker systems you can have a 4 channel system, with all the bass coming out of the subwoofer and it's off in the corner but somehow it sounds like it's coming from all around the room.  So bass is not directional, but it does have that rudder and in my opinion the bass motor is secondary, well actually it's third, in line with what is coming from up there in that horn.  But that is the essence of the Leslie speaker.

And now Hammond and Leslie are both owned by the same company. 

Yes, both Hammond and Leslie are owned by Suzuki.  They were both acquired sometime in the late 80's.  So Hammond literally bought Leslie.

Your right, the Hammond sound is not considered complete by most people's standards without the Leslie.

And the Leslie was not origonally for churches, it was a theatre organ type of thing.  It was a pastor in L.A. by the name of Eugene Small that was the first I know of to have a Hammond in his small church.  Andreé Crouch's dad, Benjamin Crouch, was pastoring a church in Pacoima and was a close second.

The Leslie speaker really came into it's own in the late 50's and went from becoming a novelty to a staple.  And it's definitely a big part of the sounds of Gospel and of course Jazz.

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