Newbie building speaker box. Help.

[planet10]

Originally posted by mgoedeke
A 75l sealed box should be in order with an F3 of 33 Hz (not bad) but a 2 dB hump around 55 Hz.

F3 of 33 is better than i would of guessed. Now taking that box and making it aperiodic will tend to reduce the hump.

dave

[mgoedeke]

Then again the T/S are suspect to begin with. WinISD pro tells me that those Qes and Qms figures ammount to a Qts 0.78 of as opposed to the 0.8 odd from the specs. This is a DVC woofer so perhaps it has something to do with the connection of the terminals.

33 Hz surprized me as well, but then again a 12" with a VAS of 82l and Fs of 30 Hz make for 85 dB@2.83V@1m. I have a little (=30l) 10" with a 1,5 dB hump and it's perfectly litenable but at a lowly 84 dB it likes a fair amount of juice and is destined for small rooms.

[intelceleronman]

With what must I build the box?

[intelceleronman]

Here is a pic of the sub.

[mgoedeke]

I would go for MDF (called supawood here) if you can, but otherwise you might have to use whatever you can get your hands on. Simple butt joints should do the trick and with some clamping you wouldn’t even need screws. Try and see whether you can get someone with a router to do the driver cut out for you. If at all possible, try and get the wood cut for you. Remember that we are talking about 75l internal and you can use dimensions to best suit the applications and even at 60l with moderate stuffing you might still be ok, but less than that is not any good. Because this is a sub the dimensions can even be equal. Don’t forget to brace the box and to leave room for the driver’s magnet assembly. You can make a sealed box “appear” larger to the driver by stuffing it with some pillow stuffing or similar, but at the moment the budget might be a little strained as is so don’t go overboard. Obviously the more stuffing the larger the box will appear but the mains will be marginal.

If you have questions about building the box you may gladly shoot them to me using the email button below.