Dayton 8" DVC Sub Design

[69stingray]

Hello everyone. I finally have speaker workshop up and running. I am designing a passive subwoofer for my computer speakers. Each channel (LH & RH) will feed into each coil (one channel per coil). I will also have pre-made 100-Hz low-pass filers for each coil.

Here are my measured specs after break-in:

(wired in parallel)

Re: 3.2 ohms
Fs: 33.6 Hz
Vas: 36.33 Liters
Qts: 0.505
Qms: 4.061
Qes: 0.577
Le: 0.518 mH

I am proposing 30-Liters net internal with a 2" Precision Port tuned to 34 Hz, giving me a F3 of 32-Hz, which is low enough for me. Speakers will be used for music only.

Thoughts?

Driver: Dayton SD215-88 8" Shielded DVC Subwoofer

[69stingray]

Here is the air-speed at max. excursion. Input voltage exceeds what the main speakers can handle, so I will probably never see this air speed.

[chubby chaser]

I see your post was over looked or knowone is in the helping mood. Stingray Im building a sub with the dayton 10" dvc subwoofer with the 10" passive radiator and 100 watt dayton amp. I was going to start a thread for help on my project but saw you were having problems getting help. I have a plan B if this forum does not work out. But plan B means the saw dust will fly and fly and fly. I will build a few boxs and see which sounds best. When in doubt do it cave man style. lol

[TerryO]

Chubby,

I'll give you some good advice, get yourself another 10 inch Passive Radiator. The general rule on PRs is to have 1.5 to 2X's the area of the active driver. The hot set-up would be to have the active driver front firing and a PR on the left and right sides of the cabinet. This allows the opposing PRs' to counteract and cancel the force of the PR's cone, which should allow the cabinet to stay stationary instead of "walking" across the floor.
Good luck on your project!

Best Regards,
TerryO

[chubby chaser]

Hey Terry o thanks for the reply and advise. Truthfully I sort of caught my mistake of ordering only one passive after it arrived. I was toying with using just one but you are right 2 are needed. Below are the numbers I ran and came up with. What do you think will this make for a decent sounding sub? It will be used in my wifes gym with the zaph b3s system in surround sound. Being new to the unibox program and sub/speaker building I have quit a learning curb but am willing to put in the time to learn. I accept all input on this project and appreciate constructive criticism. Do you think Im on the right track? Check out the new graph with the 2 passive radiators. It didnt really change that much.

No of PR's 2
Fsp 19.50 Hz
Mmp 400.0 g
Qmp 2.50
Sdp 340.0 cm2
Xpmax peak 10.00 mm
Vasp 54.1 l
Cmp 0.083 mm/N
Rmp 39.207 kg/s
Design by Vb, Mmp and Q
Physical Vb 42.5 l
Absorption, Qa 80
Leakage, Ql 15
Alpha, a 2.554
My, u 0.800
Vb 43.2 l
Fb 29.25 Hz
h 1.170
F3 39.81 Hz
Response peak 0.52 dB
Peak at 77.98 Hz

[chubby chaser]

I finished the drawings to the dayton 10" sub with two passive radiators. Cave man style. No fancy auto cad for me no sir. Give me a slate slab and a bone chisel any ole day of the week.

[chubby chaser]

Here is a progress report. I cut three sub boxes out of mdf and started working on the largest a 107 l box. Unibox gave me the lowest hz results using a larger box so Ill give it a try first. I have two other boxes to build after this one. A 47liter box and a 72 liter box.

[69stingray]

Keep us posted, I will probably not get to mine until X-mas week! I got as far as buying the birch veneered plywood I plan on using...

[chubby chaser]

I tried to post some pictures but the system will not allow me to post them. Go figure. Im playing with the internal bracing now. I plan on using veneer also with the iron on method. Hope its idiot proof.

[chubby chaser]

So i built the 107 liter double passive radiator sub and tried it for a couple weeks and was not impressed at all ( i dont think the 100wats of power is enough to push two weighted down passives with that large enclosure) so i dove into the 47 liter closed box and it seems to work out better. This sub is only good for a small room i tried it in my living room 20'x20'(+,-) and the bass was lost. I put it in my bed room for a few weeks and it sounds ok with two of the b3s i have set up temporarily. So i have a 107 liter double passive sub box that is headed to the chain saw.