Infrasonic Speaker - Need advice for undergrad thesis project

[Barleywater]

Have you explored bass shakers?

For measurement at these frequencies small speaker can be implemented as a microphone.

Regards,

Andrew

[gberchin]

Originally Posted by Rive

The downside is that I could only perform my composition for one person at a time. Also, my area of focus is in the sort of ambient infrasound, the kind that is subtly experienced. I feel that the obvious shaking that occurs from tactile transducers is going to misrepresent infrasound.

Mount the shakers to something that will act as a diaphragm, like a false wall or ceiling.

[lightlinked]

what is your budget? I built one of these Lab12 - Tapped Horn - for an interactive new media bull poop installation when I was in college. It will reasonably hit 16 hz and lower if you are careful. however its quite impractical afterwards, too low for a pa sub, great for a theater. its BIG. Building it wasn't too bad but if you've never used a table saw before it might be a tad ambitious. you might be better off with a dual 18 and careful management with a max msp patch since most speaker management dsp wont go below 20hz.

[Speedskater]

If your university has a large technical department, maybe you could use a large industrial shaker table.

[jwmbro]

Hi,
if you want to go low, you need to go big. I have an idea for a dual LAB-12 big box horn that might suffice, and depending on your wood costs could be <800$. But it's a 3000l monster - floor to ceiling height, over 1m^2 cross section, and probably about 10 (!) sheets of plywood to build. But it would do 120db from 10Hz and up if properly corner loaded.

I doubt you can get much more than that at your budget using traditional drivers - low frequencies eat cone excursion for breakfast, and unless you can control it with proper horn loading, you'll run out soon. And horn loading at this frequency requires vast truck-length horns - think 20 thousand liters or more. Probably not in the money/time budget to build

[Ron E]

Originally Posted by Rive

In order to play with this idea musically, I first need to be able to produce infrasonic tones.

The cheapest way to produce LOUD infrasound is to place a sealed speaker enclosure inside a chamber of rather low volume. Say, use a 12-15" woofer in a sealed box, placed inside a small pickup truck cab.

[Moondog55]

Google for the big Clarion
Clarion SRW8000 32"
It was designed to use the smallest possible cab AFAIK using Rod Elliots technique
No longer available but 2 to 4 of those and a megawatt of power perhaps in a tight room

[freax]

Originally Posted by Speedskater

If your university has a large technical department, maybe you could use a large industrial shaker table.

bah, just sit ontop of a washing machine during the spin cycle = 5Hz-10Hz

[DUG]

Think outside of the box:

ACP&D Limited - How servo hydraulic amplifiers work
Woodward | Hydraulic Amplifier

I don't know about cost, but it is another way.

[weltersys]

Originally Posted by Rive

The downside is that I could only perform my composition for one person at a time. Also, my area of focus is in the sort of ambient infrasound, the kind that is subtly experienced. I feel that the obvious shaking that occurs from tactile transducers is going to misrepresent infrasound.

Another down side of tactile transducers (ButtKickers, shakers, etc.) is that they need to be high passed, long durations of sub 40 Hz will burn the motor windings.

A 10 Hz wave is 110 feet long, you should look at room mode calculations for the dimensions of the venue you plan to use.

Unfortunately, room modes will make drastic differences in response at different frequencies and locations, so audience members will not have the same auditory (or tactile) experience.

An outdoor playback would take the room mode problems out of the equation, but would also reduce the SPL.

You have chosen an interesting thesis..