I am building a modest home theater sub - I had an 8" car subwoofer already and since I don't have a HT sub or the $$ to buy the one I would like 
I thought I'd see what I could do with this.
I have the box almost built - about 1.2 cub. feet not including bracing, etc. I used 3/4" MDF, sealed with caulk, etc. I have a couple of questions:
1) ports? I plan to use 2 ports - 2" diameter, and according to the only multiple port formula I could find, about 4.5" long each. Does that seem right? According to the formula, that should tune it to about 32hz with the speaker specs and box size.
2) batting? I plan to put batting in the box to help its accoustics, and the woofer is a downward firing woofer. Do I need to build something inside the box to keep the batting up off the speaker? I was thinking of a kind of "net" built out of 3/16" dowel rods to to keep it up right above the speaker - is that a good/bad idea?
3) amp? I am looking for a 100 watt +/- amp. I was looking at the ApexJr amp at: http://www.apexjr.com/ApexJunior.htm and wondered if anyone had any experiance with this or similair, or had any recomendations? I could possibly build my own given a kit, but am not sure I'm ready to try that unless its a drastic price decrease.
Also, I was thinking of just building a "side" cabinent onto the back of the sub box to hold the amp, rather than cutting into the cabinent itself and sitting the amp down in. Any pros/cons to this? I would make sure that the fins were ventilated, but want the option of using the box somewhere else if (when?) I get a larger HT sub.
thanks for any and all help! This is my first HT speaker project (i'v done a few car sub boxes). I'm hoping it all comes out well. I'v been taking pics of the work, and will post a site when done.
Mike
I thought I'd see what I could do with this.I have the box almost built - about 1.2 cub. feet not including bracing, etc. I used 3/4" MDF, sealed with caulk, etc. I have a couple of questions:
1) ports? I plan to use 2 ports - 2" diameter, and according to the only multiple port formula I could find, about 4.5" long each. Does that seem right? According to the formula, that should tune it to about 32hz with the speaker specs and box size.
2) batting? I plan to put batting in the box to help its accoustics, and the woofer is a downward firing woofer. Do I need to build something inside the box to keep the batting up off the speaker? I was thinking of a kind of "net" built out of 3/16" dowel rods to to keep it up right above the speaker - is that a good/bad idea?
3) amp? I am looking for a 100 watt +/- amp. I was looking at the ApexJr amp at: http://www.apexjr.com/ApexJunior.htm and wondered if anyone had any experiance with this or similair, or had any recomendations? I could possibly build my own given a kit, but am not sure I'm ready to try that unless its a drastic price decrease.
Also, I was thinking of just building a "side" cabinent onto the back of the sub box to hold the amp, rather than cutting into the cabinent itself and sitting the amp down in. Any pros/cons to this? I would make sure that the fins were ventilated, but want the option of using the box somewhere else if (when?) I get a larger HT sub.
thanks for any and all help! This is my first HT speaker project (i'v done a few car sub boxes). I'm hoping it all comes out well. I'v been taking pics of the work, and will post a site when done.
Mike
TS Parameters
Heres the parameters I have from the tech sheet. I don't think I have the equipment to measure it yet, but let me know what I would need (or point me to the proper thread), if you could - I would like to do this with my whole system.
Vas 0.75
Qts 0.55
Fs 36.80
Displacement (CuIn) 38.00
SPL 84.50
Mounting Depth 3 13/16
Qms 10.18
Qes 0.58
Pmax 100.00
Xmax (mm) 7.50
I have a 1.2 cu ft. box half built at the moment (top is not attached yet) - no port holes drilled yet - probably soon though.
The tech sheet recommended a .5 to 1.2 cub. ft enclosure with or without a port. I could definately use some help figuring out the port length/size - I have 2" PVC pipe to use if that will work. If it wouldn't hurt, I would like to use 2 ports (for looks and to reduce the total length of the port).
Thanks!
Mike
Heres the parameters I have from the tech sheet. I don't think I have the equipment to measure it yet, but let me know what I would need (or point me to the proper thread), if you could - I would like to do this with my whole system.
Vas 0.75
Qts 0.55
Fs 36.80
Displacement (CuIn) 38.00
SPL 84.50
Mounting Depth 3 13/16
Qms 10.18
Qes 0.58
Pmax 100.00
Xmax (mm) 7.50
I have a 1.2 cu ft. box half built at the moment (top is not attached yet) - no port holes drilled yet - probably soon though.
The tech sheet recommended a .5 to 1.2 cub. ft enclosure with or without a port. I could definately use some help figuring out the port length/size - I have 2" PVC pipe to use if that will work. If it wouldn't hurt, I would like to use 2 ports (for looks and to reduce the total length of the port).
Thanks!
Mike
For the box/port size numbers, use a free design package such as WinISD. Enter the T/S parameters and it will give you a box and port size to start with.
To measure the T/S parameters (if you don't want to accept the ones that you've already got) takes a little more work. Download Speaker Workshop. You may want to build a Jig to do all the tests. It's takes some time but it's well worth it and you can use it in future projects. Do a search on these packages. There's a lot of help out there for you
To measure the T/S parameters (if you don't want to accept the ones that you've already got) takes a little more work. Download Speaker Workshop. You may want to build a Jig to do all the tests. It's takes some time but it's well worth it and you can use it in future projects. Do a search on these packages. There's a lot of help out there for you
ok - I've been playing around with WinISD (where was this program when I started this project!?!)
According to the program, if I put in a port tuning of 40htz and a 1.2 cb ft box - if I use 2 ports of 2" diameter they need to be 0.182 inches long - does that seem right? Everything I was getting was in the range of 4-5 inches for 2 ports, trying to do it by hand.
I'm using the specs THEY have in their database for the calculations, which could be part of the difference. Are they generally accurate? I'm not 100% on the specs I have as I have an older model and thats the best Kicker could give me (Its a Comp 8" Kicker sub, 4ohm)
Thanks for the help!
Mike
The other program recommended looks great also!
According to the program, if I put in a port tuning of 40htz and a 1.2 cb ft box - if I use 2 ports of 2" diameter they need to be 0.182 inches long - does that seem right? Everything I was getting was in the range of 4-5 inches for 2 ports, trying to do it by hand.
I'm using the specs THEY have in their database for the calculations, which could be part of the difference. Are they generally accurate? I'm not 100% on the specs I have as I have an older model and thats the best Kicker could give me (Its a Comp 8" Kicker sub, 4ohm)
Thanks for the help!
Mike
The other program recommended looks great also!
In winISD beta (alpha only lists solobaric) I only find two possible matches for the description you gave for your driver "Its a Comp 8" Kicker sub, 4ohm". (assuming the "C" means Comp)
Kicker C-8-4
and
Kicker C8C-4
Neither of them have T/S specs resembling the ones you posted. You'd be better off to get ALL the T/S specs and plug them in yourself, or better yet, measure them yourself and try it.
I've had great success with winISD modeling a sub for my home theater. There was no confusion about the ports. If you plug in the T/S specs and choose a ported configuration It'll tell you ideal box and port dimensions. Change the number of ports and it'll tell you the new dimensions for them. As you've probably figured out .182 is a bit short for the port. Try a larger diameter.
Kicker C-8-4
and
Kicker C8C-4
Neither of them have T/S specs resembling the ones you posted. You'd be better off to get ALL the T/S specs and plug them in yourself, or better yet, measure them yourself and try it.
I've had great success with winISD modeling a sub for my home theater. There was no confusion about the ports. If you plug in the T/S specs and choose a ported configuration It'll tell you ideal box and port dimensions. Change the number of ports and it'll tell you the new dimensions for them. As you've probably figured out .182 is a bit short for the port. Try a larger diameter.
BTW,
when I modeled the C8C-4 to the box and ports you mentioned it says the port length should be .182 METERS, not inches. Click on the M next to port length to scroll through different units of measurment until you get to in. (came out to 7.17")
The C-8-4 models almost identically to the first (7.18") and has almost exactly the same response curve when overlayed.
when I modeled the C8C-4 to the box and ports you mentioned it says the port length should be .182 METERS, not inches. Click on the M next to port length to scroll through different units of measurment until you get to in. (came out to 7.17")
The C-8-4 models almost identically to the first (7.18") and has almost exactly the same response curve when overlayed.
That would make sense - 7.17" not .182" - I was having a couple of problems of that sort when I first put the #s in making sure I used the correct measurement. You were right that it is the C8-4 Kicker.
Yep - my program shows the same. I don't know why I didn't try that - i think at first it was saying inches, and it musta got changed at some point.
Thanks!
Mike
(As far as the specs, my sub is an older model, so I'm not sure if the specs I have are right, or the ones in the program are - I am probably going to build a jig and use Speaker Tester program to check it out.)
Yep - my program shows the same. I don't know why I didn't try that - i think at first it was saying inches, and it musta got changed at some point.
Thanks!
Mike
(As far as the specs, my sub is an older model, so I'm not sure if the specs I have are right, or the ones in the program are - I am probably going to build a jig and use Speaker Tester program to check it out.)
Hey behnkem!
You see, all it took was those TS Parameters to get the
ball rolling.
The most I can tell you is use the TS parameters supplied
with your woofer. Alot of times they (Speaker companies)
update their specs, and, you will see two different TS chart
listings.
If your speakers came with a TS sheet, use that for reference.
The Program I use is Eminence Designner, and, Bass Box
Pro. The one I posted was the Eminence.
Best Regards,
You see, all it took was those TS Parameters to get the
ball rolling.
The most I can tell you is use the TS parameters supplied
with your woofer. Alot of times they (Speaker companies)
update their specs, and, you will see two different TS chart
listings.
If your speakers came with a TS sheet, use that for reference.
The Program I use is Eminence Designner, and, Bass Box
Pro. The one I posted was the Eminence.
Best Regards,
keep polyfill off speaker?
Thanks Omni and everybody for the responses.
I have one question left - if I use polyfill in the box, do I need to keep it up off the speaker in some manner? The speaker is a downward firing speaker, and I was concerned about the polyfill resting on it, especially while playing.
I was planning on covering the insides with foam to help the acoustics - will this help or is it unnecessary?
Thanks!
Mike
Thanks Omni and everybody for the responses.
I have one question left - if I use polyfill in the box, do I need to keep it up off the speaker in some manner? The speaker is a downward firing speaker, and I was concerned about the polyfill resting on it, especially while playing.
I was planning on covering the insides with foam to help the acoustics - will this help or is it unnecessary?
Thanks!
Mike
pictures
Since you guys have been helping me out, I thought you may lilke a few pics to show the progress so far:
(I'll post the links so as not to take up a ton of room here)
http://www.moneyfromyourcomputer.com/screwed.jpg
http://www.moneyfromyourcomputer.com/painted.jpg
http://www.moneyfromyourcomputer.com/leg-oops.jpg
http://www.moneyfromyourcomputer.com/kickerC8.jpg
I have the ports done, (not attached, but holes and PVC pipe are both cut-pipe is painted(inside)) but I don't have the pics upoaded off the camera yet.
Mike
PS, the paint is just for the legs - I plan to cover with some carpet scraps I have.
Since you guys have been helping me out, I thought you may lilke a few pics to show the progress so far:
(I'll post the links so as not to take up a ton of room here)
http://www.moneyfromyourcomputer.com/screwed.jpg
http://www.moneyfromyourcomputer.com/painted.jpg
http://www.moneyfromyourcomputer.com/leg-oops.jpg
http://www.moneyfromyourcomputer.com/kickerC8.jpg
I have the ports done, (not attached, but holes and PVC pipe are both cut-pipe is painted(inside)) but I don't have the pics upoaded off the camera yet.
Mike
PS, the paint is just for the legs - I plan to cover with some carpet scraps I have.
Behnkem,
Here is a finish option that is both easy and cheap.. Go to Parts
Express and check out thier Vinyl Laminate
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
Available in Black Ash, Teak, Cherry, Beech and Textured Black.
Check out my DIY Sub (12" Sealed Stryke AV-12 Powered by a
500 Watt RMS Bob Carver Sunfire TDC Amp) 14" x 14" x 15"
which I temporarily covered with the PE Vinyl just so I didn't have
to look at naked MDF.. This stuff is no worse than what many
OEM speaker builders use!
My Sub: http://www.westol.com/~brettd/temp/mysub/
As for the Pollyfill and keeping it off of the driver, You could buy
some 3M Spray Adhesive and spray the side walls and top inside
with the adhesive and loosely affix the Polyfill to the walls to keep
it off and out of the drivers cone/motor.
Here is a finish option that is both easy and cheap.. Go to Parts
Express and check out thier Vinyl Laminate
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
Available in Black Ash, Teak, Cherry, Beech and Textured Black.
Check out my DIY Sub (12" Sealed Stryke AV-12 Powered by a
500 Watt RMS Bob Carver Sunfire TDC Amp) 14" x 14" x 15"
which I temporarily covered with the PE Vinyl just so I didn't have
to look at naked MDF.. This stuff is no worse than what many
OEM speaker builders use!
My Sub: http://www.westol.com/~brettd/temp/mysub/
As for the Pollyfill and keeping it off of the driver, You could buy
some 3M Spray Adhesive and spray the side walls and top inside
with the adhesive and loosely affix the Polyfill to the walls to keep
it off and out of the drivers cone/motor.
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