subwoofer enclosure volume

Airplay355

im building a sub for my friends car....im going to use the stryke av12. im using a program called boxplot to help me figure out what size box i need. after entering the parameters of the woofer the program decided i should build a box with an internal volume of 2.46 cu ft, stryke's website gives the f3 and f10 for that driver in two suggested enclosure sizes, 1 and 3 cu ft. does this mean that i should only build boxes of those sizes? or can i build a box with a volume of anywhere between 1 and 3 cu ft based on the fr curve i want?

please don't redirect me to the car audio section, i know where i posted

PolkThug

I would go ahead and try what the program says. That's about the size of my sealed box which has 2 12's.

Regards,
PolkThug

pjdami

Airplay,

The 2.46 cu. ft. will give you a Q of 0.61 which is a good design and in between the two designs Stryke has shown on their website. Good luck with your first project. A sealed sub is pretty forgiving to put together if you make it airtight.

I tried to post the output of the WinISD program I used but it looks like crap once I shrink it down to a size that is postable

I can email the jpg to you if you would like but it looks just like the ones on the Stryke website (just in between).

gatemplin

You can build any size box based on the Q you want. If you want a specific recommendation for box dimensions and fill for the AV12, give John Janowitz a shout, he would know better than we would.

Airplay355

what si the Q a representation of? the turn out of the fr graph once the woofer is in the box?

pjdami

http://www.carstereo.com/help/Articles.cfm?id=29

Airplay355

ok, i've used winisd to compare graphs using different box sizes....it seems that large differences in size don't accumulate for much in sound differences with a sealed box. my only problem would seem to be how to make the box airtight, and how to cut a good circle out of the mdf? any suggestions?

pjdami

My brother used liquid nails and wood screws to hold the MDF together in the sealed box he built.

here are some tips:

http://www.carstereo.com/help/Articles.cfm?id=46

You could use a rotary saw to cut circles. Or you could start by drilling some smaller holes to get started and use a jigsaw.

Airplay355

wow that site helped alot, thanks....the only thing im not so sure about is the bracing, does that have to be very sophisticated? what do i need to do?

gatemplin

For this application, you could use dowel or 2X2 or left over scraps etc to connect opposite sides. Use glue and screws to secure the braces. I like to use silicone in the inside corners of the box to make sure it is airtight.

You can see an example of the bracing in this Tempest sub.
http://hometheatertalk.com/httalk/viewtopic.php?t=7189&highlight=tempest+sealed

http://hometheatertalk.com/httalk/viewtopic.php?t=8321&highlight=tempest+sealed

It aint pretty but it will do the job.

Airplay355

i think ill stick with a cross brace of 2x2's

can you paint MDF? Is it hard to do? what kind of results do you get? can you get a glossy finish like the one on the lsi's on it? if so, how?

gatemplin

You can paint MDF. The ends suck up paint like a sponge so I use a primer. It turns out okay but I prefer the spray on finishes or real wood veneer. I haven't tried the high gloss finish on paint, but I know it takes a lot time and a lot of sanding.

If you are using the 2x2s, brace the top and bottom, the left and right side and then secure the rear wall to the other two braces. The box will be very solid.

Airplay355

thanks guys....this sub enclosure will become a reality in about a week. im going to maine and im going to build it up wthere with my uncle, who has enough tools to open a shop, and enough smarts to write a book. ( hes an architect, so i think he would help considerably lol)

how do spray on finishes look? and as long as i prime the wood i can paint it with anything?

gatemplin

Originally posted by Airplay355

how do spray on finishes look? and as long as i prime the wood i can paint it with anything?

I used a latex primer and Krylon Make it Stone on a sub. It tuned out great and the texture is very durable.
Here is an example
http://quicksitebuilder.cnet.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=http://quicksitebuilder.cnet.com/wrnch2/sitebuildercontent/sitebuilderpictures/shivatemp.jpg&target=tlx_new
Others have used the automotive textured finishes which are more durable.

Airplay355

how much did it cost to make do your entire sub? my sub is gonna be around 1100 square inches, not accounting for the hole of the driver. how much do u think that would cost?

PolkThug

Are you just making a rectangular box to put in the trunk, or are you making a custom fit "looks like its factory equipment" kind of enclosure? If its just a box, I would carpet it, otherwise it will easily get scratched up.

Regards,
PolkThug

gatemplin

Originally posted by Airplay355
how much did it cost to make do your entire sub? my sub is gonna be around 1100 square inches, not accounting for the hole of the driver. how much do u think that would cost?

My sub looks like the light grey one in the photo. It cost about $50-60 because my sub is over 4 feet tall. If you are going to put the sub in a trunk, it is probably best to use trunk bed liner which is more durable and much cheaper. Maybe $10, there are some tricks to it so it might be a good idea to search the DIY forum at HTF.

Airplay355

well it doesnt matter what i do now because im not building it anymore.

my friend just tol me his "mom" won't let him buy a sub. so if anyone wants a winisd file for a stryke sealed i got it lol sorry for all the hype, i really thought i was gonna build it. everything was all ready, i just had to build it. oh well