Opinions on box build, please.

[bikinpunk 10+ year member]

First off, I have a 12w7 and 1000/1. I built a box a while back but it's way too big for my new car (2006 Civic Sedan) so I took it out. The box was roughly 2 sq ft net, tuned to about 30 hz. I liked the response and how accurate the bass response was, and it also had a good mix of 'boominess' that I liked. However, I noticed on certain songs it acted like it wouldn't even play the bass lines (PERFECT EXAMPLE is "Number 1 Stunna", I know, I know...). Anyway, I had plans to wait until closer to christmas time to build a fiberglass box but I'm really starting to get eager not having the low end in my system anymore. I downloaded WinISD today and was playing around with some dimensions there and I came up with this plan:

2.5 cubes

Tuned to 33hz (might go to 35)

Port lenght for 3" round port- 3.9". With a mach # of 0.19.

If I go with a 4" round I get a lenght of 7.9" with a mach # of 0.11.

My question is this: which port would be best? Noone local sells round port tubes so I'd have to order from Crutchfield. They have a 3" Diameter, 4" length & a 4" Diameter, 12" length.

Like I said previously, I have a slot-port box I built myself so I'm fairly comforatable with building a new box, it's just the plans that I want to get nailed down right. I looked at JL's recommended box but I don't plan to build a rectangular box. If I do build out of MDF I'll do a slant on the back at AROUND 70 degrees (a very rough estimate since I'm trying to visual the angle of the rear seats). I wouldn't like for it to extend any further than about 20 inches and be shorter than 16" and I figure width to be about 25". I know that doesn't leave me much, but it's what I've got to work with. If I get enough feedback I'll post back definate dimensions tomorrow morning.

I appreciate anyone who has read this far and I appreciate any would-be help. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Also, I'm considering making this face the rear seats instead of into the trunk lid. Does anyone have any experience with doing this? I would think there would be more pressure build-up in that area which might cause my trunk area to rattle more....I'll be Damplifying that in a few months anyway though.

Click to read more...

 

[xluben 10+ year member]

i don't know what version of winisd you have, but mine shows the port air velocity in m/s not percentage of mach. if it does show percentage of mach (which seems correct by the numbers you gave) you'll need way more port area. 0.05 is the max recommended mach number. (which equates to 17m/s)

i loaded that driver in to winisd alpha, and for 2.5ft^3 @ 33Hz with 1000W it says you'll need four 4" ports, each one being 46" long, to get just under 17m/s.

i'd shoot for at least two aero ports or 30+ in^2 of non-flared port area (maybe another slot port).

 

[bikinpunk 10+ year member]

I've got winISD 0.44.

I get a mach number (#) of .11 which is roughly equivalent to 37.4 m/s.

Other parameters I played around with, hopefully these will work better:

2.5 Cubic Foot

Tuned to 35hz

# of Ports _________Round Port Diameter (in)_________Length (in)________Mach %

_____2____________________3___________________________10_______________0.05

_____2____________________4___________________________18.75_____________0.03

I don't think I can achieve a port with a lenght of 18.75" so I'd likely go with a 3" round port. Also, (2) 3" ports at 10" lenght gives port velocity of 10.208 m/s.

I'm leaning toward a round port enclosure to save on wood, thus saving weight on the back end of my car. My last box was about 50lbs + 43lbs for the 12w7, sitting right on the rear tires.

 

[MisterGrubbs 5,000+ posts]

Tune lower FTW

 

[xluben 10+ year member]

wasn't the port velocity the reason why they came up with the alpha version?

what i get is WAY higher than that.

 

[bikinpunk 10+ year member]

I tried another run using BBP 6.

Tuned to 30hz with 1.8 internal volume. The max db I get is about 118.

I'd like to achieve more but my dimensions are really limited to the dimensions I have in the picture below.

If anyone has time I would really appreciate some help. I need no wider than 30", no taller than 15", and would like to stay under 15" deep. I'm choosing a slanted face since that would give me a little more area to work with and would fit nicely against the back seats.

Here are some screen shots from Bass Box Pro: (also, here is a link to d/l it using torrent- http://btjunkie.org/search?q=bass+box+pro)

12w7 Parameters:

Dimensions I tried using:

Port Dimensions:

Graph I recieved with above dimensions:

Any ideas on what I can do to achive a higher SPL? Also, will tuning low guarantee that I get those LOW bass notes (ie: "bia bia", "Soul Survivor"). I'm trying to make a good all-around box. I listen to rap and country (weird, huh) more than rock, but I still do listen to occasional rock.

 

[bikinpunk 10+ year member]

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[bikinpunk 10+ year member]

Bump