Loudspeaker Design

I’ll often come across new acoustical inventions that will “change the world,” and usually these claims have next to no basis in reality (I will save the “cone of silence” for a future post – it’s a running gag in our office). There is some misunderstanding (if I’m being generous) or blatant misrepresentation of what’s actually going on and what is actually possible.

The Acoustical Society of America publishes quick reviews of recent acoustical patents. I saw this one for a novel loudspeaker design and literally burst out laughing.

This loudspeaker design is a good example of wishful wizardry in full bloom… [At] low frequencies, the speakers are driven “push-pull,” allowing the back chamber volume to be reduced to almost nothing. Of course, the resulting low frequency output is also reduced to almost nothing. That side effect is not mentioned in the patent.

https://asa.scitation.org/doi/10.1121/1.5040485

The Cistern auralization

This comes from my time back at RPI.  One of the projects in the department was live auralizations of spaces.  Basically, you play into a microphone, and a bunch of speakers make it sound like you’re in a different space (on a related note, this was one of the techniques I used in my Master’s thesis).

This particular auralization was set up in the main concert hall at EMPAC on campus to be used for an upcoming concert.  The space it is emulating is a cistern (giant underground water tank) at Fort Worden State Park in Washington.  It has a reverb time of about 40 seconds and a very smooth decay curve.  This means that if you play a note, it will hang around for a very long time, so you can play chords with yourself.

Being part of the acoustics department, I had the chance to go in while it was being set up and tested.  Being a musician, I had my trombone nearby.  So, naturally, I got set up and just started playing.  It’s a weird experience.  I was in there for at least 2 hours just noodling around, but it felt so much shorter than that (that’s what this video is from).  I went back in and set up some recording equipment and played for another couple hours, but that recording unfortunately failed – some setting or connection got messed up and I was left with a crackly, unlistenable mess.  Ah well – you live and you learn.

There were also some tour groups that came through that day, and one of them caught some video.

Presented for your enjoyment:
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