Help needed - For making a subwoofer using 2x15" Fostex FW405

[gautamz]

Hi,

I had put up my existing speakers for sale sometime back.
That didn't happen.

Rather than ditch the speakers I was thinking of using the two 15" Fostex FW405N make a subwoofer.

I do not want the subwoofer to be too big or vibrate too much. I want the bass output to be low, tight, fast and detailed. I hate boomy base.

Now I do not know head nor tail of making subwoofers, I tried a few sites but couldn't zero on a suitable idea.
One idea seems to be to set up like the B&W PV1 or the B&O Beolab 11 but they use small drivers and exotic shapes.

I would love to set the two woofers, back to back, into a sphere, I am even ok with a box (easier to make) - but what would be the ideal size and can I reduce the size by stuffing the insides with some material? Also where can I get such a sphere?

Any help would be appreciated.

Tech specs of FW405 -
Qts - 0.34
Fs - 20Hz
Xmax - 7mm

 

[shershah]

Hi,

I had put up my existing speakers for sale sometime back.
That didn't happen.

Rather than ditch the speakers I was thinking of using the two 15" Fostex FW405N make a subwoofer.

I do not want the subwoofer to be too big or vibrate too much. I want the bass output to be low, tight, fast and detailed. I hate boomy base.

Now I do not know head nor tail of making subwoofers, I tried a few sites but couldn't zero on a suitable idea.
One idea seems to be to set up like the B&W PV1 or the B&O Beolab 11 but they use small drivers and exotic shapes.

I would love to set the two woofers, back to back, into a sphere, I am even ok with a box (easier to make) - but what would be the ideal size and can I reduce the size by stuffing the insides with some material? Also where can I get such a sphere?

Any help would be appreciated.

Tech specs of FW405 -
Qts - 0.34
Fs - 20Hz
Xmax - 7mm

but hey

https://www.madisound.com/store/product_info.php?products_id=8207

this looks like a PRO woofer mean for sound reinforcement modules at large venues, and this will require large cabs,

if this is used at a home, essentially, it will be used to cater to small disco and private parties where SPL (sound pressure levels) are more important than fidelous reproduction of recorded material

you will need a refrigerator sized cabinet to make this work at home.

abandon the idea

 

[anilva]

Check elsewhere on the net. This speaker would need very large enclosure for making a sub out of this. Expected to be around 300-360 litres. Quite big.

 

[gautamz]

Check elsewhere on the net. This speaker would need very large enclosure for making a sub out of this. Expected to be around 300-360 litres. Quite big.

I know it will end up being big.
The calculators suggest a Vb of approx 11cubic feet for a ported design (port of 4 inches dia)
That would mean a cylinder approx 25inch (~2feet) dia and 42inch (~3.5feet) height.
If done right I could have this double duty as a bottom firing centre/coffee table

I get the fact that the subwoofer might end up being big - I just remembered an article (can't find it) where I read that by using a particular type of filling, a smaller volume could be used. I was hoping I could be guided to that.

 

[midnitefreakin]

I would suggest u make 2 subs, one for self and sell the other one ...i m sure this one would be a hot cake

All the best!

 

[t.antony]

... I just remembered an article (can't find it) where I read that by using a particular type of filling, a smaller volume could be used. I was hoping I could be guided to that.

For smaller volume, you can try an aperiodic sub. Your woofers seems to be suitable for aperiodic loading.

Scan-speak aperiodic vents are available at Madisound- https://www.madisound.com/store/product_info.php?cPath=404_85&products_id=1323

Found this : AP Enclosures-The Aperiodic Cookbook | Tutorials | Team Audionutz

 

[gautamz]

Hmmm... it seems a simple way to diy myself a sub with these speakers is not going to be possible.

Ces't la vie. At least the wife is going to be happy

If anyone would like to get there hands on these drivers let me know. I'll anyways be putting them on the for sale section shortly.