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JLanep25
04-07-2003, 12:03 AM
Can anyone help me? I have a truck with a cover on the bed. I need some help buiding a box. I am goin to use a bandpass box in the bed and I already have a 8 inch hole cut through the cab (port) I am goin to use Two Kicker cvr 12" subs. can you please help me with box size, port lenght and a good tuning freguency. I already built a box and Im using it, just want to build a new one. On the sealed side I have 1.0 cu. ft. per sub and on the port side I have 3.0 cu. ft. with a port size of 8 in. and 3in sticking out of the box goin into the cab of the truck. (the port I am using now does not go in the box.) can you please help me figure what my tuning freguency is for that box also. Thanks

evo2k3
04-07-2003, 09:53 PM
Originally posted by JLanep25
Can anyone help me? I have a truck with a cover on the bed. I need some help buiding a box. I am goin to use a bandpass box in the bed and I already have a 8 inch hole cut through the cab (port) I am goin to use Two Kicker cvr 12" subs. can you please help me with box size, port lenght and a good tuning freguency. I already built a box and Im using it, just want to build a new one. On the sealed side I have 1.0 cu. ft. per sub and on the port side I have 3.0 cu. ft. with a port size of 8 in. and 3in sticking out of the box goin into the cab of the truck. (the port I am using now does not go in the box.) can you please help me figure what my tuning freguency is for that box also. Thanks

sounds like your talking about ported, not bandpass -- since you mentioned nothing about order....if so, we need the displament of the drivers -- what are you talking about the sealed side and the ported side? need the net volume of the box after all displaments to calculate tunning frequency.

JLanep25
04-07-2003, 11:54 PM
I beleive its what you call a 4th order bandpass. the subs fire into a chamber that is 3.0 cu. ft. with a port of 8 in.

paikiah
04-08-2003, 01:45 AM
Originally posted by JLanep25
I beleive its what you call a 4th order bandpass. the subs fire into a chamber that is 3.0 cu. ft. with a port of 8 in.

8" port? That's gonna be one LONGGGGGGGGGGGGG port.....

hmm, why are you so set on a bandpass? WHy don't you build yourself a waterproof ported box with the port entering the cabin? The sub can fire below, and with the right ridges, you don't need to worry about water getting on your cones. The ast time I checked, my ported sub on my PC speaker, not a peep from the cone, all from the ports, so I'm thinking maybe it's not important for one to face the cone to hear the bass...

JLanep25
04-08-2003, 02:34 AM
Well personally i really dont like bandpass boxes, but when i bought the truck it had a 8 in. or a lil bigger hole cut in the bed, I bought it from a friend he had a nice sounding system in it with the specs I have given. So I built a box similiar to his. But now I wanna do something a little diff. But it sounds really good, just not as clean as I would like it. The box i have now has a 8 inch port ,3 inches long coming out of the box goin into the cab. thanks

paikiah
04-08-2003, 04:01 AM
Originally posted by JLanep25
Well personally i really dont like bandpass boxes, but when i bought the truck it had a 8 in. or a lil bigger hole cut in the bed, I bought it from a friend he had a nice sounding system in it with the specs I have given. So I built a box similiar to his. But now I wanna do something a little diff. But it sounds really good, just not as clean as I would like it. The box i have now has a 8 inch port ,3 inches long coming out of the box goin into the cab. thanks

erm, so the port at 3" in length... did you put that pipe to suit the distance between the cab and the cabin, or was it properly calculated and figure that port size was ideal?

I've played around a bit with winisd pro a bit, and by enlarging the diameter of any port, the length grows to impossible lengths... 5" ports can give you ridiculous numbers... and 8"..whoa, never tried that yet....

JLanep25
04-08-2003, 01:11 PM
Yes, the three inches is the distance from box to inside the cab. Well can you help me figure out something? thanks

paikiah
04-08-2003, 08:46 PM
OK, so you want to utilise the 8" gaping hole that's between the back and your cabin...

doesn't mean you GOTTA fill it up, so maybe a smaller slot port or 2 X 3" ports...you should be able to cover the rest with fiberglass resin and silicone after passing the appropriate cables through...

anyhow, I need the parameters for your subs...like Pe, Qts, etc.....

Also, you SURE you want a bandpass? Might want to think about a simple ported enclosure... or sealed with the subcone facing the 8" hole...

if it's pounding you want, then I'd suggest a ported...easier to build, less chance of going wrong than bandpass...

Oh, and what size of a box do you want? The volume would matter the most, really...

JLanep25
04-10-2003, 02:44 PM
Kicker CVR 12 4 Ohms
SPL. 86.4 Db
SD,SgM. .05321
Bl, Tm 18.3
Vas, Cu.Ft. 3.28
Mms,gms. 151.47
Fs,Hz. 26.8
Qms. 9.38
Qes. .596
Qts. .561
Pmax .400
Xmax,mm 11.5
Freq. Response,Hz 25-500

paikiah
04-10-2003, 11:37 PM
OK, I input your numbers on WinISD pro...

your box is tuned to 70Hz (8" diameter, 3" length)

You ain't getting much of anything below 45Hz... but your subs don't go very low anyhow...

hmmm, dont' see a drastic difference between sealed and ported... and sicne I don't have any amp power to it, I can't see the cone excursion to see what ports are ideal...

what kinda power are you sending these babies?

JLanep25
04-11-2003, 01:35 AM
I am using a kicker ZR 240 Bridged at 2 ohms, not sure on wattage.

paikiah
04-11-2003, 02:03 AM
your amp puts out 300w@2ohms bridged...

your current bandpass has a narrow peak of 60~80Hz.

You didn't specify how much volume you have to work with, so I just assumed 5CuFt...

a ported box tuned to 37Hz will give you louder bass, compared to sealed, from 35Hz onwards... drops a little from around 52Hz, but will still be louder than a sealed...

you will need two ports to minimise length and turbulence, if using 4" ports...

4" diamteter, 7.01" in length...

8" diameter, 14.7" in length...(that'd mean you've gotta bend the port with "elbows", and take up more volume, hence, larger box)

Hip hop music bass tunes hit, on average, from 40~60Hz, so this box shouldn't have any problems handling that... maximum dB reached at 50Hz, 124.5dB. That's loud enough for me.. should be louder once the ports enter the cabin.

xmax (23.057mm both ways) is reached at 25.86Hz, so it's just right for a Harrison Labs 25Hz FMOD inline subsonic filter...

JLanep25
04-11-2003, 04:17 AM
Ok so you are just sayiny forget the 4th order bandpass and go with a vented box right? and as far as room, the box is in the bed of the truck so i have all the room in the world. Thanks

paikiah
04-11-2003, 04:26 AM
Originally posted by JLanep25
Ok so you are just sayiny forget the 4th order bandpass and go with a vented box right? and as far as room, the box is in the bed of the truck so i have all the room in the world. Thanks

yeah, ditch the box....

if you wanna use the 8", I've given you the measurements, and 14" might not be so unachieveable, if the pipe can run into the cabin and snake its way a bit behind the seats... then you can have all 14" in the cabin, no need to have extra braces for the port and taking up volume...

if you're creative, I'm sure you can do wonders with the pipes...:)

JLanep25
04-11-2003, 04:32 AM
Ok if i ditch the box and make a vented one where are my subs goin to fire? The Subs are in the back of the truck. So I kinda got to have a bandpass. Thanks and sorry for all the trouble Do you have a aol sn?

paikiah
04-11-2003, 05:07 AM
Originally posted by JLanep25
Ok if i ditch the box and make a vented one where are my subs goin to fire? The Subs are in the back of the truck. So I kinda got to have a bandpass. Thanks and sorry for all the trouble Do you have a aol sn?

Well, as stated before, my computer PC has a subwoofer (Altec Lansing) and my bro's PC has a BOse system... both of them, there's not a peep from the cones, the sound's all delievered from the ports. SO that's why I siad you could have the cone facing downwards and with ridges, you can protect it from normal elements, even water, unless your cab floods...

JLanep25
04-11-2003, 02:54 PM
OK thanks for all the help.