Infinite Baffle Double Bass Array

[Flaesh]

What about my thread https://www.audiosciencereview.com/...-low-q-subs-quasi-plain-wave-radiation.24396/ ?
And René's thread https://www.audiosciencereview.com/...of-the-double-bass-array-configuration.37943/ ?

I want an infinite baffle

I had IB. But then I combined the two rooms into one. When I saw the title of this thread, I thought it was about front and rear IB)).
The mentioned threads show that constant transducer velosity (not acceleration as for spherical wave) is sufficient for constant spl for a plane wave case. So there is no need for high-Q drivers with a weak magnet.
For a cylindrical wave in an anechoic space, the amplitude drops by 3 dB per octave at a constant , but how do you ensure anechoic propagation of a cylindrical wave in a room?))

continuous row of subs across the whole width of the room

Create a row of these at half the room's height and a similar row at the rear room end. This will be the DBA. The upper limit will be limited by one transducer at a height of 2.5 m.
Or or place this your line arrays under the ceiling and it will be a CCC.
Take REW RoomSim and HornResp and model, it's simple (but simplified!!).

It's all very simple here:

And here it’s less clear, but also simple and doesn’t require special knowledge:

Four theoretical drivers in parallel and series in a room infinite horn (PWT)) 4 meters wide and 2.5 meters high 99999 sq cm cross-section. 18-inch, monster magnets, 28 volts. Gray - anechoic.

Do you have any real room measurements?

 

[welwynnick]

What about my thread https://www.audiosciencereview.com/...-low-q-subs-quasi-plain-wave-radiation.24396/ ?
And René's thread https://www.audiosciencereview.com/...of-the-double-bass-array-configuration.37943/ ?

Yes I read those too.

The mentioned threads show that constant transducer velocity (not acceleration as for spherical wave) is sufficient for constant spl for a plane wave case. So there is no need for high-Q drivers with a weak magnet.

I'm going to have to take a while to get my head round what you're saying there. That's different to my understanding (SPL proportional to acceleration).

For a cylindrical wave in an anechoic space, the amplitude drops by 3 dB per octave at a constant , but how do you ensure anechoic propagation of a cylindrical wave in a room?))

By octave, do you mean distance rather than frequency?
The rest of the post I get - thanks for the analysis.

 

[Flaesh]

By octave, do you mean distance rather than frequency?

Frequency; schematically, levels are arbitrary, constant piston velocity:

Here's a simple practical test of a room's suitability for DBA: any pair of speakers and a microphone will suffice:

The more reality resembles this, the better it will work. And again one more time

Ideally there should be nothing but the second and third longitudinal modes below 100+ Hz.

 

[NTK]

Many thanks for the modelling, I appreciate that, even if the result wasn't what I hoped. Did you model it in two dimensions? My intention is to have a continuous row of subs across the whole width of the room. It will only approximate to cylindrical waves, not plane waves.
It looks like the tunnel outlet makes little difference. That's a bit of a surprise, as all that air has to go somewhere. Maybe the tunnel is attenuating the waves, which both a good thing and a bad thing. It's bad because it doesn't help cancellation, but good because it means I might be able to use this glorified transmission line as as effective IB, without incurring negative effects. It doesn't put me off, and I'm probably going to go ahead anyway. Maybe I need to play with a wider or longer tunnel, or smoother turns or an outlet like a horn.

You are welcome! Yes. The simulations were 2-D. But since it is a time domain simulation, computation-wise they were 3-D (2 spatial dimensions plus time), and each of them take several minutes to run on my 5 years old 6-core laptop. Full 3-D (spatial) analyses will probably take 10+ times longer, plus they will also take more work to setup.