any one here design boxes? im not real fluenet with the programs i have so maybe someone here can help me.

I have the specs for my subs, but the people whom ive talked with havent been able to really help me design my enclosure. I have bass box pro and winisd...but niether of them seem to be working well with the specs i have...that or im just screwing something up. here are my specs.

I want to build a ported box for 2 of these subs. Im not looking for an spl enclosure, just a good daily driving sub box. anyhow here are the specs.(im not too sure about that xmax spec...maybe its 8 one-way)


RMS Watts 120
Peak Watts 240
Frequency Rsp 20HZ-1KHZ
Imp/Ohm 4.00
SPL (db) 87.00
Free Air 24.70 HZ
QES .190
QMS 12.640
QTS .180
VAS 39.400 LT
RE 3.400 OH
XMAX 16.000 MM


-thanks

 

what do you need help with exactly in the design? If you're just looking to model the appropriate box/curve for this sub, thats easy enough. you get to figure out how to provide the airspace and venting necessary to achieve it

First of all, what size subwoofer is it? This will determine minimum venting. But the curve is off the charts on this sub! can you double check the parameters? better yet - make/model? Here's what I came up with:

1.5 cu ft
tuning - 50 hz
vent - 4" x 6.07" (one)

this is a very high tuning to get a decent curve....not really to my liking much. the ebp was also as high as I've ever seen it go in all my years (which again, makes me wonder about the accuracy of the specs).

more info!!

bmoney

 

yeah the specs are as accurate as theyre going to get as i have spoken with the manufacture twice just to reassure the specs.

the fs on the sub is 24.7 so i was thinking i could get away with a lower tune than 50hz

they are mcm 8's the model number escapes me at the moment. I have a friend who competes and he some subs just dont model right...and we all know that everything changes once the sub is in the car anyhow...

i think if i cant get a decent box size im going to start a 1.2-1.5 cf tuned to 30-35hz and see how it is. nothing like trial and error.


thanks


55-2421...i think thats the model number

 

I believe your tuning is so high because the Qts is so low. Such a low qts usually results in a high f3 (-3dB point).

I modeled this and with a .5 cubic foot enclosure tuned to 43hz, I can get an F3 of 43hz, but it's not a real smooth frequency response.

This driver looks like it might do ok as a midbass driver, but if you're planning to use this thing as a subwoofer, you're going to be bitterly disappointed.

 

talked to my friend who competes both SPL and SQ and he says

fs is way to low to be useful as a midbass its clearly a low freq driver....and response probably wont be smooth as its a low Q driver

Right now hes at school and doesnt have the software to model me up a box...he said the sub might respond better to a larger box than the one you tried.

-thanks guys keep the input coming

 

If the box gets much larger, your f3 is going to raise. This sub is NOT well suited as a sub, dispite the low Fs. Fs is only part of what dictates how deep a sub can play.

The Qts also has nothing to do with how smooth the driver is. Qts is a spec that relates to how much control the magnet has over the voice coil. Typically a lower qts indicates better driver control, which can translate into a cleaner sound provided the rest of the design is up to par.

 

I've modelled a LOT of drivers in my day. and 99% of them fall within an "expected" norm of values that the software deals with accordingly. I have gotten to the point of mixing tuning and size to where the curve "feels" good, and it ALWAYS works out in-car the way I thought it would.

so....modelling your driver, its off the charts on the EBP scale. and the others are right about its insuitability to low frequency reqproduction....a smaller box makes the curve UGLY. the only way to get a half-normal looking response is with the box I quoted already. and that seems like a pretty high tuning...BUT, if its an 8" sub, its not too far off the mark.

what about getting a nicer driver?

bmoney

 

Not bad advice at all. You can get some VERY nice 8" subs for very little cash. You can get an 8" Tangband W8-740c or a Resonant RE8 for $50 each. Both are great little subs with a huge x-max, and a flat anechoic response down to 35hz in a .5 cubic foot ported box.