Distributed Sub Array (Swarm Sub) Driver selection (on a budget)

[Svarog98]

I want build a swarm sub array with 1 big subwoofer and 3 smaller ones and wanted to discuss with you guys what drivers would come in handy to do this.
What parameters should i be more aware of since the bass is split to 4 subs?
I have these Dayton Audio Drivers in mind right now:
12" - https://doc.soundimports.nl/pdf/brands/Dayton Audio/SD315A-88/pdf_dayton audio_SD315A-88_1.pdf
8" - https://doc.soundimports.nl/pdf/brands/Dayton Audio/DCS205-4/pdf_dayton audio_DCS205-4_1.pdf
My room is 2,2m x 6,5m x 3,4m (48m3 / around 2000 cubic feet)
I want to stay under 1000€ and i still need wood and 1 or 2 amps

 

[digitalfrost]

You could build a bass-reflex box with the big driver, 74l, 10,2cm 50cm length, -3dB will be at 34hz.

The small chassis is not really suitable for bass-reflex as you would need extremely long pipes (~1m). But if you put it into 12l closed and boost 35hz with 6dB:

It looks like this.

 

[Svarog98]

Thhanks for the quick graphs. Do they take room gain into account?

 

[digitalfrost]

Nope, it just simulates the chassis. You can export the TSP data easily from https://loudspeakerdatabase.com/ and then import in the simulation program of your choice, they offer a lot of options.

e: Just found this passive radiator for the 8" https://www.daytonaudio.com/product/1591/dsa215-pr-8-designer-series-aluminum-cone-passive-radiator Makes a lot of sense they sell these. Haven't simulated it, but I guess that would be the way to go then.

 

[Duke]

I have these Dayton Audio Drivers in mind right now:

12" - https://doc.soundimports.nl/pdf/brands/Dayton Audio/SD315A-88/pdf_dayton audio_SD315A-88_1.pdf
8" - https://doc.soundimports.nl/pdf/brands/Dayton Audio/DCS205-4/pdf_dayton audio_DCS205-4_1.pdf

That little 8" woofer looks especially good to me. Note that its motor is ALMOST as strong as the motor on the 12" woofer! So the motor-strength-to-moving-mass ratio (which ime correlates well with "impact") is significantly higher for the 8" woofer. I think you could use four of the 8" woofers instead of three + the single 12" woofer; I don't think you need the 12" woofer in order to get 20 Hz ballpark bass.

You might use an enclosure volume of about 30 liters plus allowance for driver, port, and a brace, so about 33 liters total.

You might use a 2" (50 mm) diameter port with a length of about 460 millimeters, and make the enclosure tall-and-skinny so the port will fit, oriented so it fires out the bottom.

You might cut the inner end of the port on a 45-degree angle (or steeper if feasible), such that the opening is an ellipse having a larger cross-sectional area than the port itself. Chuffing (turbulence) typically sets in first at the inner end of the port, so cutting the inner end of the port tube at an angle to increase the area of that opening is sort of like a "poor man's port flare". The outer opening already has a flat panel all around it which delays the onset of turbulence (imagine water flowing into a pipe: Having a flat surface all around the pipe opening will facilitate the fluid flow). Measure the ballpark 460 mm port length down the center of the port, so the length along the "tip" of the angled inner port end will be ballpark 473 millimeters.

Assuming you can protect the woofer against over-excursion by using a protective highpass filter at about 18 Hz, the 8" woofer should be operating within its excursion limits at its rated 150 watts input, and the port should not chuff with a 150 watt sine wave at 20 Hz. In-room extension should be in the 20 Hz ballpark unless you have a big room or an open floorplan.

If you build them and set them up and find the bass to be a bit too heavy, you might reverse the polarity of the sub positioned farthest from your main speakers. This will also increase the in-room bass smoothness, and "smooth" bass is "fast" bass.

In my opinion.