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
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
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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
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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
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
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
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
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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.
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And here is the rear of the 47 liter box. Advice to first time builders if you use hurricane nuts or tnuts epoxy them in from the rear. You will not have any problems with them pulling out if you are like me and move woofers around allot.
PS you are prolly wondering what took me so long. Believe it or not the project has been complete for awhile it took some time for me to sit down and read my camera book to figure out how to reduce the file size by putting camera on vga (image size) then go to picture quality and put it on standard. Sounds so simple now.
PS you are prolly wondering what took me so long. Believe it or not the project has been complete for awhile it took some time for me to sit down and read my camera book to figure out how to reduce the file size by putting camera on vga (image size) then go to picture quality and put it on standard. Sounds so simple now.
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Just a fyi for making the weights for the passive woofers. I took fishing weights and beat them down with a maul on a anvil. This was really very easy but be sure to weigh you weights even thou they are marked a certain weight does not mean that is what they weigh. Every weight i used was lighter than marked. Guess i should go back to store and complain. (like they would care)
PS i wonder if a gallon of gas im purchasing at pump is really a gallon
hmmmmmmmm now i have two passives i dont need wonder what i can build with them?????
PS i wonder if a gallon of gas im purchasing at pump is really a gallon
hmmmmmmmm now i have two passives i dont need wonder what i can build with them?????
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Thanks wild card. Im in the middle of building some speaker stands right now. I have some (here we go im opening up a can of worms) bose 301's iv series set up as my mains that need some stands. I have two Zaph b3s as my rears and im short a (i will be diying)center channel and a sub for this set up. I may be able to incorporate those two passives into a sub for this set up later. Any ideas on a center channel that would work out with this sort of set up?? Have a look at speaker stand ideas.
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Wellll I got a little bit done today. That square center post on this speaker stand sure reminds me of a speaker. I thought about mounting a B3s on this center post. Well tomorrow Ill route the edges and glue everything together. I hope i can do some bondo work also. Pictures will follow.
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I did the first two coats of Kilz primer sealer. Man that stuff is messy. The kilz primer/sealer has allot of over spray. I think Im putting more on the surrounding area than the piece being sprayed but it does seal the mdf nicely. I give it a full day of drying before attempting to sand. This stuff gumms up sand paper quick otherwise. I picked up some kilz satin black that Im going to give a try. I picked up 6 cans for $2.00 a can at walmart discontinued isle.
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