| boris333 |
i got a box that measures
38 " wide
21 " depth
18 " height
i m not shure what to port it to ? i m using 8 subs infinity 1220 300 RMS each 12 " i was thinking two ports on the top see pic ? |
|
|
| Bill Fitzpatrick |
You'll get more responses if you don't link to a zip file. I, for one, can't be bothered unzipping.
You're putting 8 12" woofers in a box that size? I don't think so. Ported or sealed, it's going to sound awful! |
|
|
| boris333 |
| its in bmp format dont know how to add it here any other way ? |
|
|
| Bill Fitzpatrick |
You save it as a .jpg and make sure it comfortably fits the screen. If the file size is greater than 75K, it's too big.
What about my question? |
|
|
| simon5 |
You are going to a SPL competition?
If yes, port the box around 40-50 Hz or so.
You will need T/S parameters to do this properly. |
|
|
| richie00boy |
| I deeply suspect that with 8 12 inch woofers that it's physically impossible to achieve enough vent cross sectional area to tune a box of this size to any usable frequency. |
|
|
| SkinnyBoy |
OMG!!! he took a photo of a printout of a drawing... PLEASE go away now.... :) thankyou.
alright... lol
38 " wide
21 " depth
18 " height
which is:
96.5cm X 53.3cm X 45.7cm
I'm sure youre smart, so we'll assume they're internal dimensions.
so, thats 235 litres.... lets say.... 10 litres for bracing, so 225 litres, meaning 28 litres per woofer... woofer displacement will be around 2 litres, so 26 litres per woofer.... now each woofer would need a 100mm port. (I'm ignoring whateve you came up with) so, to tune a 26 litre box to say, 40Hz (kinda high, but meh) you'd need a 20cm long port.... hmm... I'm sure you could do it... lol what was the point in this box again?? other than to be big? lol |
|
|
| Bill Fitzpatrick |
| quote: | Originally posted by SkinnyBoy
OMG!!! he took a photo of a printout of a drawing... PLEASE go away now.... :) thankyou. |
What would be worse is if it was a real photo which he then scanned and saved as a .jpg. :D |
|
|
| SkinnyBoy |
| quote: | Originally posted by Bill Fitzpatrick
What would be worse is if it was a real photo which he then scanned and saved as a .jpg. :D |
noo... wait... he took a photo of the screen... lol ah well.. |
|
|
| boris333 |
"now each woofer would need a 100mm port"
u mean if the port is in a shape of a sphere ? |
|
|
| richie00boy |
| I'd table the suggestion that 40Hz tuning is really too high for a sub. |
|
|
| LarsAC |
Why does it have to be ported? If I had that much membrane area I would go for a closed sub equalized to output low frequencies easily.
Lars |
|
|
| SkinnyBoy |
| quote: | Originally posted by richie00boy
I'd table the suggestion that 40Hz tuning is really too high for a sub. |
ofcourse its too high!!! but good luck tuning a 25 litre box to 30Hz :p lol |
|
|
| boris333 |
| i wll go sealed and see how that works out ... |
|
|
| SkinnyBoy |
| I don't actually believe any of this is going to happen... like me.. :D I design all these boxes, and ask all these questions, and do nothing.. lol :smash: |
|
|
| boris333 |
| i ll start makeing the box soon i have all the wood cut all i need to do is put it together ... but i m building lilliput projector so have no time right now for it .... |
|
|
| SkinnyBoy |
| but are those internal or external dimensions?? and I hope you have atleast 18mm mdf, with a shelf brace in the two gaps between the 3 woofers on the front/back.... may require some creativity to get it to clear the magnets on the top woofers though.... |
|
|
| boris333 |
| those wore external dimensions ... i m using 3/4 MDF and there will be some braces or not will see ?? |
|
|
| SkinnyBoy |
| external? well.. I wouldn't put anymore than 4 12inch woofers in it then... and you need bracing.... there is no "we'll see"... |
|
|
| SkinnyBoy |
can I change my story?? lol
4 in that box left sealed should be alright.... |
|
|
| darth_sanchez |
| what exactly are you using the subs for?? lol nice pic too :P |
|
|
| SkinnyBoy |
| thats the response of four in 180 litres sealed... won't get much better than that, and 8 would be horrible... thats assumign I used the right drivers.. lol |
|
|
| simon5 |
Don't be so harsh with him, he just wanted an answer to a simple question...
Here is the response of your woofers sealed in your box with bracing to stiffen it up, with 4000W RMS imput.
Don't port your box, it's too small to port it, you will gain absolutely nothing in output, the sound will also be worse. |
|
|
| darth_sanchez |
| have you already cut the holes for the box? u could clamshell each sub... just an idea |
|
|
|
