Saturday, May 28, 2005

I am a bass, I sing three notes

I don't know how I was able to lead kabbalat shabbat last night at Park Slope Minyan with my voice stricken by an ongoing cold, but I think hitting the amud a lot (for percussion) helped. I drugged myself with generic Duane Reade-brand NyQuil and fell into a tranquil and motionless sleep, but then this morning my voice was even more gone. I have to say, the dar just isn't the same experience when one doesn't have a voice. I alternated between growling out bass harmony in the limited range I could reach and just listening (relying on shomeia' k'oneh). It did sound good though.

I got there around 9:37 when the room was far from full. (Probably due to Memorial Day weekend, it never even reached standing-room-only!) The room sounded particularly resonant, with the acoustically reflective walls and not very many people, and this brought to mind an interesting optimization problem: The amount of sound produced in the room increases linearly with the number of people (or logarithmically if we're using the decibel scale, which approximates human perception of sound), but the reverberation time decreases as the number of people increases, because the total acoustic absorption increases as the people's bodies suck up sound. (For simplicity, ignore differences in frequency.) Yes, reverberation time is a property of a room that doesn't depend on the amount of sound - it is defined as the time for the sound to decay 60 dB (regardless of whether it is going from 100 to 40 or from 30 to -30). But let's define another time T' as the time for the sound to decay from its original intensity to 0 dB. What is the number of people in the basement of the Second Presbyterian Church that will maximize T'?

This was the penultimate dar of the year in this basement with good acoustics where one can wear a short-sleeved shirt and sandals; in two fortnights we'll move into the other basement with sound-killing carpet and overzealous air conditioning, so I'll have to bring a winter coat and gloves on 90-degree days.

The plan is not to talk for the rest of the 3-day weekend.


  1. That the 'dar was a different experience without a voice proves yet again, as if we ever doubted it, how absolutely vital empowered Judaism (vs. the cantor-singing-at-audience variety) is.

    And ha- I wish I'd been there to experience you singing bass. We could have actually sung melody together for once.

    Refuah sh'leymah.

  2. The optimization problem I used to play around with is the amount of soda in a soda can that would lower the center of gravity to its lowest possible point. I miss the days when I used to randomly think of these things.