Making a sub box...specifications needed!
12-22-2003, 10:52 PM
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Making a sub box...specifications needed!
EYY wsup
I've recently purchased an alpine type r 12" sub and was thinking bout buying a box. I've read articles that mention that you need the right kinda box for the best sound, so I've decided to make a sub box for my Alpine 12" type r sub. The question is...what would the dimensions be for the box? I'm a real beginner to this stuff so bear with me. Although the articles mention you need the right dimensions, they dont tell u wat the dimensions should be...Any help for specifically a box for the alpine type r 12" sub would be greatly appreciated.
Also, I'm thinking about buying a JBL BP300.1 amp to power my sub. Would the amp give enough power for the sub and, if it doesnt, what other amp should i get around the 130 dollars range?
thx in advance
I've recently purchased an alpine type r 12" sub and was thinking bout buying a box. I've read articles that mention that you need the right kinda box for the best sound, so I've decided to make a sub box for my Alpine 12" type r sub. The question is...what would the dimensions be for the box? I'm a real beginner to this stuff so bear with me. Although the articles mention you need the right dimensions, they dont tell u wat the dimensions should be...Any help for specifically a box for the alpine type r 12" sub would be greatly appreciated.
Also, I'm thinking about buying a JBL BP300.1 amp to power my sub. Would the amp give enough power for the sub and, if it doesnt, what other amp should i get around the 130 dollars range?
thx in advance
12-22-2003, 11:22 PM
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what kind of sound are you looking for first of all
there is ported and sealed (don't **** with making your own bandpass box)
sealed is the easiest. just make a box and throw the sub in (but its more than just that)
for your sub i'd recommend anywhere from 1cuft to 1.75-2 cu ft, taking into consideration that the low end extension will be easier to acheive as the volume of the box gets bigger.
sealed generally provides a tighter bass response but less high end response. what you can do to figure out the volume of the box is multiply the width, height and depth of the box and divide that number by 1728 and it will give you a number with a decimal. for instance, 14*14*16= 1.82 (cu ft). probably pushing it for a sealed box application in terms of airspace. i'd personally go with 1.3 cu ft or so with your sub. so 12*12*15=2160/1728=1.25 cu ft. i'd recommend going with this volume for a sealed box for your sub.
the reason you divide by 1728 is because that is a cubic foot. 12*12*12=1728
now ported gets more complicated. also known as vented, ported enclosures have a port or vent to let air escape from the enclosure as well as be drawn into the chamber. ported enclosures are louder than sealed enclosures. i'd recommend probably about a 1.5-2 cu ft enclosure for your sub with a ported application. i'd tune the port at about 25-30 hz or so. you want to get the ported effect but still have sound quality. once you start tuning the port to higher numbers (ie 40-60 hz) you inversely loose sound quality when the tuning frequency gets higher. how the tuning of ports is determined is the area of the port. if you're just beginning i'd recommend you'd have someone build the ported enclosure for you given the tuning frequency i recommended and whatever volume you'd like within the dimensions i recommended.
take into consideration that the bigger your enclosure is, the less power it will take for the sub to reach full excursion. if you stay within the dimensions and tuning frequencies i've said you should be perfectly fine running the RMS wattage to the sub.
how sturdy and durable your enclosure is is probably the singlemost vital aspect of your system. you can have shitty gear and put it in an awesome enclosure thats sturdy as hell and built quality, and it will slam and sound good. but you can put top knotch gear in a shitty, poorly built enclosure and it will generally sound like shit. i can't emphasize this enough
no matter who builds your enclosure, make sure that it is built of 3/4 inch MDF (medium density fiberboard) or a stronger material. plywood=no
make sure also that the enclosure is braced well on the inside (the walls are braced together to reduce the flexing of the walls)
hope this has helped you and i'm sure others will respond. feel free to ask questions
edit: the jbl 300.1 would be a great amp as long as you have a dual 4 ohm voice coil sub. you can wire the coils in parallel to present the amp with a 2 ohm load. at 2 ohms the amp puts out 300 watts RMS. perfect for the sub. but if you buy this amp, make sure that you go with a sealed box as this amp does not have a subsonic filter (basically, if you go with ported, this amp will make your bass sound kind of muddy)
there is ported and sealed (don't **** with making your own bandpass box)
sealed is the easiest. just make a box and throw the sub in (but its more than just that)
for your sub i'd recommend anywhere from 1cuft to 1.75-2 cu ft, taking into consideration that the low end extension will be easier to acheive as the volume of the box gets bigger.
sealed generally provides a tighter bass response but less high end response. what you can do to figure out the volume of the box is multiply the width, height and depth of the box and divide that number by 1728 and it will give you a number with a decimal. for instance, 14*14*16= 1.82 (cu ft). probably pushing it for a sealed box application in terms of airspace. i'd personally go with 1.3 cu ft or so with your sub. so 12*12*15=2160/1728=1.25 cu ft. i'd recommend going with this volume for a sealed box for your sub.
the reason you divide by 1728 is because that is a cubic foot. 12*12*12=1728
now ported gets more complicated. also known as vented, ported enclosures have a port or vent to let air escape from the enclosure as well as be drawn into the chamber. ported enclosures are louder than sealed enclosures. i'd recommend probably about a 1.5-2 cu ft enclosure for your sub with a ported application. i'd tune the port at about 25-30 hz or so. you want to get the ported effect but still have sound quality. once you start tuning the port to higher numbers (ie 40-60 hz) you inversely loose sound quality when the tuning frequency gets higher. how the tuning of ports is determined is the area of the port. if you're just beginning i'd recommend you'd have someone build the ported enclosure for you given the tuning frequency i recommended and whatever volume you'd like within the dimensions i recommended.
take into consideration that the bigger your enclosure is, the less power it will take for the sub to reach full excursion. if you stay within the dimensions and tuning frequencies i've said you should be perfectly fine running the RMS wattage to the sub.
how sturdy and durable your enclosure is is probably the singlemost vital aspect of your system. you can have shitty gear and put it in an awesome enclosure thats sturdy as hell and built quality, and it will slam and sound good. but you can put top knotch gear in a shitty, poorly built enclosure and it will generally sound like shit. i can't emphasize this enough
no matter who builds your enclosure, make sure that it is built of 3/4 inch MDF (medium density fiberboard) or a stronger material. plywood=no
make sure also that the enclosure is braced well on the inside (the walls are braced together to reduce the flexing of the walls)
hope this has helped you and i'm sure others will respond. feel free to ask questions
edit: the jbl 300.1 would be a great amp as long as you have a dual 4 ohm voice coil sub. you can wire the coils in parallel to present the amp with a 2 ohm load. at 2 ohms the amp puts out 300 watts RMS. perfect for the sub. but if you buy this amp, make sure that you go with a sealed box as this amp does not have a subsonic filter (basically, if you go with ported, this amp will make your bass sound kind of muddy)
12-23-2003, 05:28 PM
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Originally posted by JLAUDIOinCIVIC
wow that was alot so i didnt read it..
if u dont know how to make a box..its kinda best to buy one....
wow that was alot so i didnt read it..
if u dont know how to make a box..its kinda best to buy one....
the thread isn't for you
he can read it if he wants to
and by all means i don't recommend buying a box 90% of the time
12-24-2003, 06:30 AM
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A word of warning. If you decide to port that sub, do not plan on using that JBL amp because it does not have a subsonic filter. If you seal it, then that amp is awesome. I used to have a 300.1 and that was one bad ass little amp. The only complaint I have about it is the lack of EQ features, but ohh well, it's cheap power.
12-24-2003, 11:01 AM
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WOW!! Thx A_D seriously...ur info was just wat i was lookin for. About the box, I've seen some boxes that are slanted and some that are just a cube-shape. Would the shape of the box affect the sound of the sub? And if so, would I need to build the box differently?
thx in advance
thx in advance
12-24-2003, 11:41 AM
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Originally posted by isyiwang
WOW!! Thx A_D seriously...ur info was just wat i was lookin for. About the box, I've seen some boxes that are slanted and some that are just a cube-shape. Would the shape of the box affect the sound of the sub? And if so, would I need to build the box differently?
thx in advance
WOW!! Thx A_D seriously...ur info was just wat i was lookin for. About the box, I've seen some boxes that are slanted and some that are just a cube-shape. Would the shape of the box affect the sound of the sub? And if so, would I need to build the box differently?
thx in advance
but you can pretty much make any dimensions you want (as long as the sub has enough mounting depth and width). TWO sides can be the same length if desired but all 3 can't.
12-24-2003, 11:42 AM
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Originally posted by Surfacing171
A word of warning. If you decide to port that sub, do not plan on using that JBL amp because it does not have a subsonic filter. If you seal it, then that amp is awesome. I used to have a 300.1 and that was one bad ass little amp. The only complaint I have about it is the lack of EQ features, but ohh well, it's cheap power.
A word of warning. If you decide to port that sub, do not plan on using that JBL amp because it does not have a subsonic filter. If you seal it, then that amp is awesome. I used to have a 300.1 and that was one bad ass little amp. The only complaint I have about it is the lack of EQ features, but ohh well, it's cheap power.
Originally posted by A_D
but if you buy this amp, make sure that you go with a sealed box as this amp does not have a subsonic filter (basically, if you go with ported, this amp will make your bass sound kind of muddy)
but if you buy this amp, make sure that you go with a sealed box as this amp does not have a subsonic filter (basically, if you go with ported, this amp will make your bass sound kind of muddy)
and i'll bet you're convinced JL is the BEST car audio gear out there aren't you