Maybe this would be an easier way if anyone is willing to help.

I will post my specs for the speakers and any experienced cabinet makers maybe can give me what their dimensons would be based on these. I am getting confused by different results I am getting and I have never attempted this before so any input would be greatly appreciated.

Vas 130.000 litres
Qts 0.320
Qes 0.450
fs 26.0 Hz
Xmax 7.62 mm
Dia. 30.48 cm
PEMax 250 watts

Constants
Ro 1.18 kg/m^3
c 345.00 m/s



Desired Qtc 0.70
Qr 2.19
Vr 3.80
Vb 34.21 litres
Fb 56.9 Hz
F3 57.5 Hz

Sd 7.30E-02 m^2
Vd 5.56E-04 m^3
n0 0.005
SPL 88.9 dB/1W/1m
K1 1.372
K2 113.374
Amax 1.000
Par 1.372
Per 280 watts
PeakSPL 93 dB

thanks for your time and help

Mike

for a sealed box a very quick calculation gives a box size of around 40 liters and fb at 57hz pretty simalar to your figures.
the "golden ratio" for box dimmesions gives around 21cm x 35cm x 57cm (internal measurements)

thanks for that quick calculation

but 57 cm seems a little big or maybe it is just me

[shodan]

WOW!! What language was the first post in?

for a 12" driver the cabinet dont seem that big,says the man with 171 liter cabs and 8"drivers

here are some specs changes that were made, better than the original. does it change anything??

Vas 130.000
Qts 0.320
Qes 0.450
fs 26.0
Xmax 7.62
Dia. 30.48
PEMax 250

Constants
Ro 1.18
c 345.00



Enclosure Specifications
Desired Qtc 0.60
Qr 1.88
Vr 2.52
Vb 51.68
Fb 48.8
F3 58.9

Sd 7.30E-02
Vd 5.56E-04
n0 0.005
SPL 88.9
K1 0.741
K2 110.696
Amax 1.000
Par 0.741
Per 151
PeakSPL 113

so i have spent all afternoon researching, playing with numbers, etc. and have come to a reasonable ( I think) calculation.

1.82 cubic feet which equals 3144.96 cubic inches

a 12 " x 15" x 18.75 " (golden ratio included) enclosure equals 3375 cubic inches.

I read up to a 20% difference would not make a noticable difference.

do these dimensions make senses according to the above t/s parameters?

thanks for info!

best thing to do is a throw cabinet together and give it a listen,if you make it bigger than required then you can easily reduce the volume by adding bricks,books ect rather than having to keep rebuilding test cabs.

Have you bought this/these drivers yet?


An F3 of 50odd Hz doesn't look impressive, at least on paper anyway. If that's a sealed design, you could EQ it, or Linkwitz it etc, but as it stands, if the figures are accurate, you may be in for a bit of a disappointment!

Also , what type of subwoofer do you want to build?
Sealed, ported, specific size, specific cost.............?

I already on the driver that is why I would like to hopefully use it. It is goingbe used for a home theatre sub. I read that sealed was the best option ( not according to all) , plus easy to build for a first timer like myself. As far as cost, just cost of materials as I already have an amp. Size depends on what the calculations tell me to do. The size I have came to is posted above.


Mike

If it's just the box which you have to pay for, then even if the end result isn't all you'd hoped for, it's not exactly going to cost a lot - B&Q will cut up an 8x4 sheet of 18m MDF for around £15 (depending on the amount of cuts etc).

If it's a sealed unit you are after, you're looking at around 2cu ft.
Don't be too worried about being ultra exact - it's really not "that" important!

You may be better off though, doing a ported box of around 2.5cu ft and using a port, 12"x4" (circular), giving an F3 of about 35Hz.

However, given that increasing the volume of the sealed box to 2.5cu ft won't really affect it's performance that much, then why not build that - if it's not what you hoped for, you can the simply switch to a ported alignment by simply fitting the tuning port - no need for a new box!
You may need to watch the excursion though, at 7.6mm, it's not that big for a 12" driver.