converting unused drums into subs

[ssmith]

Hi there,
I have a pair of old norh wooden drum speakers that I no longer use. Since upgrading my other pair of norh drums, and building a pair of frugel horns, I simply have no further use for them.



I'm pondering replacing the front baffle and using them as a pair of sub enclosures -- just to provide a little bit of extra bottom end for DIY horns, but nothing too demanding as I'm not really a thumping bass freak. Otherwise they'll just be gathering dust.

The internal volume is around 13 litres, they have an opening at the back, although I could seal them.
Anyone think there would be any suitable drivers -- or tell me what things to look for in a driver spec? -- most designs I've searched seem to be much larger volumes.

thanks in advance!

[ssmith]

and here is a side view of a similar model:

[ocool_15]

That seems pretty small. I tried modeling it a bit but I didn't really get into sub frequencies. I assue your going to use a different amp and active filter it. How low of extension are you trying for?

[ssmith]

Thanks for the reply:

Yes, I would get a separate amp and would active filter it.

I also did a bit more searching, and downloaded a programme called aj sealed sub designer -- not sure I know what I'm doing, but most drivers in a similar size enclosure end up with an -3db point at around 75-80hz.

That's not very low, is it?

However, with this scanspeak driver i ended up with an F3 of 49hz in a 20 litre box ( I guess I could stuff the box to make it 'appear' slightly larger to the driver?)

Is that still a waste of time? How low do you all go???? (sorry, i'm new to subs )

[ocool_15]

I would try to go to the low 30's at least if you want it worth your time. I used a single 10" in 1 cu ft and with equalization I am in the mid to low 20s.
Tang Band has some good driver like the W8-740C and W6-1139SG which are intended for small ported boxes usually. You also may want to look at active equalization to obtain lower extension.

[ssmith]

Thanks very much for the Tang Band pointer. Modelled the W6-1139SG, and got an f3 of 38hz in a 10 litre vented.
Would need to reduce the volume and lengthen the port of the drums.

But does that seem like a decent option?

[ocool_15]

That will depend on how low your current speaker go and how low of extension you are wanting. Music generally doesn't use as much low end as movies. Note that the sensitivity is 83dB @ 1w 1m mainly due to the fact they are intended to play low in a small box.

[Cal Weldon]

Originally posted by ocool_15
W8-740C and W6-1139SG

I use both. The 6.5 is a surprising driver for the frame size but is no match for the 8. That 8 is a little workhorse but is not shielded. The 8 is on sale now at PE.

6.5 is good for up to about 100 ft^2, the 8 will do 200 ft^2, when used in pairs. Both are happier with their own amp.