Newbie w/ 18 ......need guidance

[B3NNY]

Ok so I DJ quite a bit. I had a friend of a friend give me a B&C 18PS76 http://www.bcspeakers.com/CPD/produc...?id=0000000053 . They used them in a few folded horn applications, and I guess had an extra. I'm looking to possibly use it as a sub in my set-up. I'm looking to build a box for this thing, but after doing some calcs I was getting an f3 of around 80 hz on a ported box tuned for 39 hz. Seems too high for a sub application. I need your help and suggestions. I wouldn't be using it in any large venues or large outside spaces, mostly in homes,small halls, backyards....etc. I do have the benefit of having it hooked up to my eq at all times.

[c2cthomas]

From messing around in WinISD I can only get it down to around 40Hz clean - and that takes a 12 cubic ft. box with two ports. B&C makes a quality product - but this one is a big woofer for pro sound but I don't see it working as a sub-woofer. There are others around that know a lot more than me (like the 8 year old next door) - but that's my read on it. Looks like we are in agreement with each other.

[bjorno]

Originally Posted by c2cthomas

From messing around in WinISD I can only get it down to around 40Hz clean - and that takes a 12 cubic ft. box with two ports. B&C makes a quality product - but this one is a big woofer for pro sound but I don't see it working as a sub-woofer. There are others around that know a lot more than me (like the 8 year old next door) - but that's my read on it. Looks like we are in agreement with each other.

Hi,

Try learning HR instead: A T-TQWT less than 7 cu.ft and a f-3dB about 30 Hz:

b

[m R g S r]

umm why not use the driver in the same application that your buddies used them in?

[bjorno]

Originally Posted by B3NNY

..I'm looking to possibly use it as a sub in my set-up. I'm looking to build a box for this thing, but after doing some calcs I was getting an f3 of around 80 hz on a ported box tuned for 39 hz. Seems too high for a sub application. I need your help and suggestions... backyards....etc. I do have the benefit of having it hooked up to my eq at all times.

Hi B3NNY,

Here's an another approach you can test: Modifying the Qts by inserting a series resistor that would increase the driver Qes thus push up Qts a bit.
Of course you could use your Eq too but the precision wouldn't be as accurate but the end result would be very similar...PA-sub(SQ):

b