Double Bass array

[Borat]

I have been thinking about the relative benefits of:

* Stereo Dipole Subwoofers
* Double Bass Arrray
* Distributed Subwoofers

and have come to the conclusion that all 3 technologies should be used simultaneously, but at different frequencies - although these frequencies can have any amount of overlap.

very roughly:

50hz & up -> Stereo Dipole Subs
20hz - 50hz -> Double Bass Array
20hz & down -> Distributed Subwoofers

The above numbers are used only as an example however. The ACTUAL numbers are to be determined based on the conditions in a particular room. In a room which is more wide than it is long for example DBA would not be used at all and Dipole Subs would cross directly to distributed Subs.

The question that i want to ask here is - how high can DBA reliably go ? I could theoretically calculate it but i would rather hear some real-world numbers if you guys have any ? Whats the highest frequency at which anybody was able to achieve ruler flat response across the listening area with DBA ?

[LineArray]

Originally Posted by Borat

...
20hz & down -> Distributed Subwoofers
...

Borat ... sometimes it makes me wonder
which kind of drugs you are using (and where to get them)

[Borat]

Originally Posted by LineArray

Borat ... sometimes it makes me wonder
which kind of drugs you are using (and where to get them)

to be perfectly honest i think all relevant content in music stops at around 32 hz.

and yet in practice i only seem to achieve the bass that i like when i equalize to as low as i can ( which is about 15 - 20 hz ).

once you're already below room pressurization ( and in my room it starts at about 30 hz ) you might as well go all the way down.

in an outdoor event i would not try to go below about 35 hz, and response down to DC would obviously be theoretically impossible.

in a tightly pressurized space like a luxury car's cabin response down to DC would add virtually no cost over response down to 40 hz.

so you have to consider cost vs benefit, and it would depend on the particular room.

but to get ACCURATE bass i would strive to get response about 1 octave beyond the lowest frequency present in music to be reproduced. Unless you maybe can come up with some FIR brick wall subwoofer filters, which i don't think exist ( at least commercially ) as of the time of this writing.

[LineArray]

I bet you already know this one:

YouTube - rotary woofer

[Borat]

Originally Posted by LineArray

I bet you already know this one:

YouTube - rotary woofer

yes but i think it is pointless.

when you're in a car and somebody slams the trunk lid closed the pain in your ears is infrasound. no fan necessary.

all you need is for displacement to be a certain fraction of room volume plus some more displacement to count for leaks and flex.

of course if the leaks are significant ( like an open door ) you will never get to DC. the fan would have an advantage in such a room.

but i think it is wiser not to cause problems like that than to try solving them.

besides, the main limitation with subwoofers is SPACE not drivers.

[event horizon]

Originally Posted by Borat

once you're already below room pressurization ( and in my room it starts at about 30 hz ) you might as well go all the way down.

I agree with that totally Once you get below the lowest standing wave then there are no more room related problems & you might as well go deep

I can hear just below 20Hz in my room & yet the lowest frequency it should be able to produce is 40Hz due to room dimensions. I can feel it down to below 15Hz though with no difficulty.

I guess it depends what you listen to music wise but i have quite a lot that extends well below 30Hz so to me it's more than valid

[Borat]

Originally Posted by event horizon

So all this talk of saving planet Earth, well that's not the problem. Planet earth doesn't need saving, it's a great survivor. It's not the planet we should be worrying about, it's us!

YouTube - George Carlin - Saving the Planet

[NEO Dan]

Originally Posted by Borat

the pain in your ears is infrasound.

One man's pain is another man's pleasure

[jason_watkins]

@borat I'm not sure anyone has a model for where DBA breaks down fully supported by measurement, but from the DBA thread the measurements there make it pretty clear you start getting problems once the array's are no longer summing coherently as a pseudo plane wave. I think another question is how much diffraction around large objects in the room (ie characteristic dimensions 1m or more) affects the response.

[Borat]

Originally Posted by jason_watkins

@borat I'm not sure anyone has a model for where DBA breaks down fully supported by measurement, but from the DBA thread the measurements there make it pretty clear you start getting problems once the array's are no longer summing coherently as a pseudo plane wave. I think another question is how much diffraction around large objects in the room (ie characteristic dimensions 1m or more) affects the response.

well where is that thread - link ?