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Thread: Hammonds, Leslies and more...

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    Hammonds, Leslies and more...

    The CD The Hammond Connection - CD-19402/Opus3, has a photo of the rear of the Hammond B3 with the following text:

    Rear view of the Leslie loudspeaker - a very important part of the "Hammond sound". Note uppermost and inside, the rotating double horn-like device which produces the highly complex vibrato and tremolo pattern.

    James Benatti Lansing
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    Quote Originally Posted by Benatti View Post
    The CD The Hammond Connection - CD-19402/Opus3, has a photo of the rear of the Hammond B3 with the following text:

    Rear view of the Leslie loudspeaker - a very important part of the "Hammond sound". Note uppermost and inside, the rotating double horn-like device which produces the highly complex vibrato and tremolo pattern.

    James Benatti Lansing
    Only one side of the horn works. The other is closed off and only serves as a counterbalance.

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    Quote Originally Posted by toddalin View Post
    Only one side of the horn works. The other is closed off and only serves as a counterbalance.
    toddalin,

    Do you have some photos and/or specifications of this system?
    He would like to know more on this subject.

    James Benatti Lansing

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    Quote Originally Posted by Benatti View Post
    toddalin,

    Do you have some photos and/or specifications of this system?
    He would like to know more on this subject.

    James Benatti Lansing
    Sort of off topic, but see the pic of this transparent Leslie:



    These are not original components though and therefore do not produce the original sound.

    While the actual horn and working parts appear correct, the original horn driver is a Jensen.

    Note the baffles in front of the actual horn opening to disperse sound. Still, the horn beneath the baffle only routed sound up one side of the assembly. If the sound came out both sides, Leslies would loose some of their characteristic sound.

    When you hear a leslie in a real live situation, it is not like recorded music as the sound is "thown" around the room, rather than back and forth across your speakers. To truely appreciate the Leslie, it must be heard live.

    You hear the doppler shift and the sound gets loudest as the open side of the horn approaches you. As it spins away, you hear it go quiet. As it approaches the inside wall of the front of the chamber, away from you (everyone runs their Leslies backward toward the audience for most volume and less internal dispersion), it again gets louder as the sound is reflects off the back of the front wall toward you. But not as loud as when it actually was facing you. Also, there is a shift in timbre as treble is lost in this reflected sound.

    It continues to spin and gets quiet again now facing the other side of the cabinet before spinning back to its loudest point at the rear, facing the audience or microphone.

    If both sides of the horn were open, it would sound the same when it points forward or rearward.

    The woofer should be a CTS or Eminance with a square magnet assembly. There could also be a dust cloth around the lower drum.

    The main amp is rated at 40 watts RMS and (if memory serves), 60 watts peak using a pair of 6550s. Crossover was at 800 Hz. If the unit were an RV (reverb), there would be an addition 16 watt tube amp mounted in the top chamber driving a Jensen 6"x9" mounted in one side of the main portion of the central enclosure. Like the horn, while both sides of the enclosure were "louvered" for the 6"x9", it was only installed on one side and the other had a block-off plate.

    Some of the Leslies had a rectangular port on the rear cover (mine included). I don't really see how it could have done much, because contrary to the clear Leslie shown, the corner of the piece of wood that the woofer was mounted on (right front corner in picure) was cut out between the central chamber and lower chamber. Also contrary to the picture, there was no chamber around the horn motors and air leaked there too.

    Leslies were also designed these for other makes of organs, and later multi-channel Hammonds made use of additional 6"x9"s and could use the blocked off louvers.

    The Leslie with my H324 Hammond actually had the 15" with the lower drum, some stationary 6"x9"s for the other channels, and instead of the horn, a pair of 6"x9"s were rotated in the upper portion. Contact was through brushes.

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    toddalin,
    Many thanks a lot for the explanations. Plus that learn on these fantastic organ.
    James Benatti Lansing

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    Quote Originally Posted by toddalin View Post
    Sort of off topic, but see the pic of this transparent Leslie:



    These are not original components though and therefore do not produce the original sound.

    While the actual horn and working parts appear correct, the original horn driver is a Jensen.

    Note the baffles in front of the actual horn opening to disperse sound. Still, the horn beneath the baffle only routed sound up one side of the assembly. If the sound came out both sides, Leslies would loose some of their characteristic sound.

    When you hear a leslie in a real live situation, it is not like recorded music as the sound is "thown" around the room, rather than back and forth across your speakers. To truely appreciate the Leslie, it must be heard live.

    You hear the doppler shift and the sound gets loudest as the open side of the horn approaches you. As it spins away, you hear it go quiet. As it approaches the inside wall of the front of the chamber, away from you (everyone runs their Leslies backward toward the audience for most volume and less internal dispersion), it again gets louder as the sound is reflects off the back of the front wall toward you. But not as loud as when it actually was facing you. Also, there is a shift in timbre as treble is lost in this reflected sound.

    It continues to spin and gets quiet again now facing the other side of the cabinet before spinning back to its loudest point at the rear, facing the audience or microphone.

    If both sides of the horn were open, it would sound the same when it points forward or rearward.

    The woofer should be a CTS or Eminance with a square magnet assembly. There could also be a dust cloth around the lower drum.

    The main amp is rated at 40 watts RMS and (if memory serves), 60 watts peak using a pair of 6550s. Crossover was at 800 Hz. If the unit were an RV (reverb), there would be an addition 16 watt tube amp mounted in the top chamber driving a Jensen 6"x9" mounted in one side of the main portion of the central enclosure. Like the horn, while both sides of the enclosure were "louvered" for the 6"x9", it was only installed on one side and the other had a block-off plate.

    Some of the Leslies had a rectangular port on the rear cover (mine included). I don't really see how it could have done much, because contrary to the clear Leslie shown, the corner of the piece of wood that the woofer was mounted on (right front corner in picure) was cut out between the central chamber and lower chamber. Also contrary to the picture, there was no chamber around the horn motors and air leaked there too.

    Leslies were also designed these for other makes of organs, and later multi-channel Hammonds made use of additional 6"x9"s and could use the blocked off louvers.

    The Leslie with my H324 Hammond actually had the 15" with the lower drum, some stationary 6"x9"s for the other channels, and instead of the horn, a pair of 6"x9"s were rotated in the upper portion. Contact was through brushes.
    I beg to differ. It looks like an appropriate 147 leslie to me. Dad had a 122 with the on/off rotor. The 15' was a Jensen with a round alnico magnet. The horn driver was a Jensen, also.

    This appears to be a working model.

    Scotty.
    ps. I am still fixing Hammond tone-wheel organs and tube-type Leslie's.
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    Quote Originally Posted by SMKSoundPro View Post
    I beg to differ. It looks like an appropriate 147 leslie to me. Dad had a 122 with the on/off rotor. The 15' was a Jensen with a round alnico magnet. The horn driver was a Jensen, also.

    This appears to be a working model.
    I'm with Scotty on this one. I'd also add, that some of the best Leslie's I've heard have swapped in some old JBL's in-place of the Jensen.

    Quote Originally Posted by toddalin View Post
    Note the baffles in front of the actual horn opening to disperse sound. Still, the horn beneath the baffle only routed sound up one side of the assembly. If the sound came out both sides, Leslies would loose some of their characteristic sound.
    I must not be understanding you - what do you mean "one side of the assembly"...? If you mean that twinned rotating horn? Both are "active", all the time.

    Quote Originally Posted by toddalin View Post
    You hear the doppler shift and the sound gets loudest as the open side of the horn approaches you.
    Again, aren't both horns active? You hear the doppler affect on each horn as the assembly rotates.

    Quote Originally Posted by toddalin View Post
    (everyone runs their Leslies backward toward the audience for most volume and less internal dispersion)
    No. Players may do that for themselves but it has little/no impact in the audience position. We use ours "pretty side front" and mic through the louvers.

    FWIW, we run our leslies pretty side forward, and mic only one cabinet. I use two SM57's on the Hi rotor - one on each side (not shoved into the rear cabinet opening). This mic'ing assures we get excellent reproduction of the twin doppler effect you are trying to describe. These inputs are panned mid-hemisphere R/L respectively. The Lo rotor gets either a 421 or SM52 - something with a larger diaphragm - positioned anywhere on the low louvers. If stuffed into the rear, the rotor's wind noise is unacceptible. This input is panned C.

    Love the Leslie...
    bo

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    The high frequencies do only eminate from one of the horns of the "treble" rotor on a Leslie. The passage from the driver throat only goes to one horn, the other is for balance.
    I love Leslies...I played organ in the 70's just to have control of that sound....! They're dirt simple and one of the most classic "aural" sounds there is. Early models were one speed, off or fast. The two speed models weren't built till the middle 50's.
    I have a hybrid/mutt Leslie for myself...it has a 16 ohm 2226 in the bottom, but an antique Atlas driver in the top. Hammond orans are done making frequencies at about 6K, a top end driver that goes much past that is not necessary, detrimental in fact. If I ever see a real good deal on a single 2470 or 2482, it'll go there.

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    Quote Originally Posted by boputnam View Post
    FWIW, we run our leslies pretty side forward, and mic only one cabinet. I use two SM57's on the Hi rotor - one on each side (not shoved into the rear cabinet opening). This mic'ing assures we get excellent reproduction of the twin doppler effect you are trying to describe. These inputs are panned mid-hemisphere R/L respectively. The Lo rotor gets either a 421 or SM52 - something with a larger diaphragm - positioned anywhere on the low louvers. If stuffed into the rear, the rotor's wind noise is unacceptible. This input is panned C. Love the Leslie...
    This is the same way I mic'd a leslie when we doing Rocky Horror live on stage with a great band last year. I used a beta 57 on each side of the upper rotor, panned just like you did. Then I had a EV RE20 for the bottom rotor. The keyboardist dug the sound in the room.

    So glad to know someone else mics it the same way! Every time he leaned on the organ, I leaned a little bit on the lower rotor. Man, it was heaven! I just sat there and thought of my dad.

    Scotty.
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    [quote=boputnam;220697]
    "I must not be understanding you - what do you mean "one side of the assembly"...? If you mean that twinned rotating horn? Both are "active", all the time. "

    No, you are wrong.

    "Again, aren't both horns active? You hear the doppler affect on each horn as the assembly rotates."

    No, wrong again.

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    Quote Originally Posted by Tim Rinkerman View Post
    I love Leslies...I played organ in the 70's just to have control of that sound....!
    Here's an interesting later model "concert set" for sale in SF: http://sfbay.craigslist.org/eby/msg/837033896.html

    Not the classics you're talking about, but I'll bet they really put out...

    John
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    Quote Originally Posted by toddalin View Post
    No, wrong again.
    You are right, again.

    Your original post got me curious - I only get to spend chance minutes around the cabinet and I'm not an organist - so I double-checked and I did have it wrong. There's good info on Wikipedia including much you posted, and another at Unearthing the Mysteries of the Leslie Cabinet with this cutaway of the rotating horn.

    I should know better than to doubt you, Todd, you are such a good tinker'er!
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    Quote Originally Posted by johnaec View Post
    Here's an interesting later model "concert set" for sale in Denver: http://sfbay.craigslist.org/eby/msg/837033896.html

    Not the classics you're talking about, but I'll bet they really put out...

    John
    These used solid state amps, so lost some of that characteric sound. These could be had with JBLs from the factory, but not the 075s. Someone must have added those later.

    The tweeters would do more harm than good for a Hammond. (But these had provisions for a 1/4" jack high impedience input through the combo pedal so could be used for anything.)

    As was stated above, the Hammond is all done by ~6,000 Hz. Recognize that the Hammond wave form is a sine wave so there are no harmonics per se. Sounds are made by stacking sine waves on top of sine waves, hense the drawbars. You are essentually synthesizing the desired wave form out of sine waves. That's why a Hammond can have millions of sounds, but they still all sound like a Hammond.

    What the tweeters will do for a Hammond is amplify the "key click" that some find annoying.

    When you listen to a Hammond, especially the low notes played individually, you hear a very distinct "click" at the onset of the sound some of the time. (With no internal guts to cover this sound, mine was very notable if played though a high fidelity system rather than a Leslie, but some people actually like that sound.)

    Because the tone generators put out their sine waves continually, whether a key is pressed or not, when you do press a key, you could be "keying in" anywhere on that sine wave. If you press a key and the wave is near the zero point, the note comes on nice and "smooth." But, if you press the key and the wave is at a crest or trough, it squares off the leading edge of the sine wave generating odd harmonics, and that characteristic "click" sound. This is known as "keying on a transient."

    This is somewhat alleviated by using a high resistance coating on the buss bars that the keys actually contact. There is a buss bar for each drawbar (9) and each key has an associated gold wire (9) attached to the key that makes contact when the key is pressed. The wire pushes through the coating giving a more gradual leading edge to the wave reducing the transient noise.

    Part of regular maintenance on Hammonds includes oiling the motor and gears and rotating the buss bars against the key contacts to clean them off.

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    Quote Originally Posted by toddalin View Post
    As was stated above, the Hammond is all done by ~6,000 Hz.
    Todd, I cannot find this reference - but if you have a second, can you explain this a bit further?

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    Laurens Hammond was an inventor and an engineer, he could not play his own instrument! He was a pretty remarkable individual in his day. There is a pretty good book about Hammond and Leslie(Don) called "Beauty and the B"..you get the whole story behind both of the guys famous for the Hammond/Leslie sound. Hammond defended the accuracy and purity of his tone generation system to the time of his death. He detested what the Leslie speaker did to the sound of his organ, and did everything possible to keep the two apart. There are many great stories of the rivalry between Hammond and Leslie...if you were a Hammond dealer and tried selling Leslies with them, he would pull your dealership. He made it so that the organ power supply was in the Hammond tone cabinet so you could not use the organ without it. The big selling point of Hammonds is that as long as you have 60hz. power, it will never be out of tune. The "tonewheels" ,96 of them, spin on shafts geared and connected to a 60hz. synchronous motor..Hammond INVENTED the synchronous motor to run clocks. The tone wheels look like gears cut with different pitches, or tooth sizes..they each spin next to a magnetic pick up, the bumps on the wheel spinning in front of the pick up creates the tone. The higher frequencies are made by wheels wth fine "teeth", the lower ones are made by wheels with fewer teeth, down to some that only have two. The highest frequencies that could have been produced in this way was limited to the gear cutting technology of the day...they couldn't accurately cut teeth any finer than the ones that produce the highest tones in the organ. (We're talking about a mechanism that remained basically unchanged from the 1930's to the 70's).
    I didn't want to totally hijack this thread,explaining the way tones and harmonics are added and layered would take a bit...

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