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Re: 1935 King Rotary CC

Posted: Sat Jul 21, 2018 5:39 pm
by PRO
Hi York-A-Holic, I have trouble with PM. Could you please call 908-850-1636 or email
proscientific AT verizon DOT net. Thanks. Paul.

Re: 1935 King Rotary CC

Posted: Sat Jul 21, 2018 8:58 pm
by SousaWarrior9
Drool

Re: 1935 King Rotary CC

Posted: Sun Jul 22, 2018 8:57 am
by EdFirth
Great informative post. There was a post a little while back about Richard Fraiser with a B flat that had that same straight forward bell. Ihave a B flat with the "polite" bell front and the engraving seems to be very close to what you have there. I guess back in the day some people wanted to really hear the tuba and not fight the time lag of the upright bell. Best of luck finding it a new home. If we didn't just replace our AC, our generator, and our son's car it would be coming here to live. Ed

Re: 1935 King Rotary CC

Posted: Thu Sep 13, 2018 3:06 pm
by iiipopes
EdFirth wrote:I guess back in the day some people wanted to really hear the tuba and not fight the time lag of the upright bell.
Indeed. That is how, in the first generation of sound recording with acoustic equipment before microphones, they came to be called "recording bells."

Re: 1935 King rotary valve CC

Posted: Fri Sep 14, 2018 6:43 am
by PRO
Common error. There is no "time lag".

Early recording systems did not use microphones. Rather, they used "square exponential horns" to gather the sound. The entire band or orchestra sat packed-closely-together, directly in front of the horn. Exponential horns favor high frequencies. One engineering challenge was to gather as much acoustical power as possible at low frequencies. One solution was to face the tuba bell forward, so that the full acoustical power of the instrument, including all harmonics, was pointed directly at the horn.

Re: 1935 King rotary valve CC

Posted: Fri Sep 14, 2018 9:57 am
by EdFirth
I wasn't referring to recordings. If you stand in front of a brass section with the trumpets and trombones pointed at you and the bell of the tuba pointed off the left the tuba sounds on the back of the beat.It's simple acoustics, the sound goes where the bell points. If you can't hear it I'm sorry.

Re: 1935 King rotary valve CC

Posted: Sat Sep 15, 2018 8:18 am
by PRO
Ed,

You state, "It's simple acoustics, the sound goes where the bell points." If that were true, then one would not hear a tuba unless it were pointed directly at one.

To explain your misunderstanding, consider the radiation pattern of the bell. The frequency content of the signal varies with angle from the sound axis (i.e., the centerline of the bell bore) -- the further from the sound axis, the richer in lower frequencies. Also consider that the crispness of an "attack" (i.e., the initiation of sound) is conveyed by the higher frequencies. Your example has us hearing sound from the side of an upright bell pointing upward. Because the sound one hears from the side of a bell tends to be richer in low frequencies, it is relatively harder to hear the attack from the side of a bell than from directly in front of it. Although one may subjectively interpret this as a "delay", it is emphatically not due to travel time and there is no "time lag".

If you want a deeper understanding of the subject, please study the following acoustical terms -- frequency content, rise time, arrival time, impedance, radiation pattern, directionality, reflection, absorption, interference, and diffraction. You will encounter other interesting concepts as you study. Especially helpful to study diagrams of radiation patterns of monopole and dipole sources. The deeper one gets into the subject, the more one discovers that acoustics, including musical acoustics, is not "simple".

Paul.

Re: 1935 King rotary valve CC

Posted: Sat Sep 15, 2018 7:17 pm
by Heavy_Metal
YORK-aholic, you have "only" 9 tubas? :twisted: