Subwoofer project, opinions plesee.

I'm new to this forum so please bear with me with my lack of knowledge, that is why I'm here after all ☺️

I currently have a Bk monolith plus sub which I'm very happy with and want to add another one. This is where my problem begins.

My wife, who has been incredibly tolerant over the years with my hifi & home theatre purchases has finally put her foot down and said NO to another monolith plus. Not because of the expense, to use her words "were not having another big black monstrosity sat in here".

So, we came to a compromise. If i build two subs and make them look like side tables (walnut veneer, the works) she will be happy with that. I'm no stranger to joinery and confident in my skills, also having a brother as a joiner helps!

The subs are for home theatre only.

My initial thought is to use the same driver and plate amp that go into the monolith, but I'm hoping for opinions and suggestions on drivers and amps. I've been comparing drivers, cabinet volumes and port sizes in Winisd to get ideas but I'm no expert!


The maximum cabinet size I can go to is 18.5"W x 19"H x 32"L and would prefer them to be downfiring, vented subs keeping to a similar tuning as the monolith.
Budget around £1000 for the pair.

What do you think?
 
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Hi. I'd look into 4 x AD12-300, which is the same driver used in the monolith -http://www.bkelec.com/HiFi/Drive_Units/Audio_Drive/AD12-300.htm

Then buy a PA amp that can be bridged into 4 Ohms, or stereo 2 Ohm per channel. I'm sure you can put two AD12-300 in each box with the sizes you've given both ported. I use a Crown XLS 1502 which can do 1550W into single 4 ohm load.

With this you'd basically be getting 4 monolith, probably equivalent to 3 Monolith plus.

Just not quite sure if you'd manage to squeeze two into each
Of the box size you're quoting, with a port tuning in the low 20's, which is where I suspect the monolith is.
 
Or you could build two boxes, each with a single driver, youd definitely be able to put a single AD12-300 ported in the sizes you're quoting. But then you have an annoying situation where most Amps are bridgeable into a 4 ohm load, and you'll be voltage / impedance limited with two drivers - youd only get the watts for a 8 ohm load. This is exactly the issue I have. I have two 4 ohm drivers in series on my crown amp so not fully taking advantage of what's available. You could look for 2 15 inch 8 ohm drivers but not sure if any exist available in UK
 
Will you be restricted to the placement of the subs being that they're now side tables? And if so, will their placement (despite now having multiple) actually result in increased output at your listening position, or even as much as you currently have?

Just something worth considering. I've done the coffee table sub thing before for WAF and it was a failure for this very reason unfortunately. I would've been better off with a smaller sub off in the corner of the room.
 
Or you could build two boxes, each with a single driver, youd definitely be able to put a single AD12-300 ported in the sizes you're quoting.

The idea is to have two boxes each with a single driver, ive been looking at the Lab12 as a possibility.

Will you be restricted to the placement of the subs being that they're now side tables? And if so, will their placement (despite now having multiple) actually result in increased output at your listening position, or even as much as you currently have?

Just something worth considering. I've done the coffee table sub thing before for WAF and it was a failure for this very reason unfortunately. I would've been better off with a smaller sub off in the corner of the room.

Yes, i will be restricted in their position, and that's something i hadn't considered. They would be either side of the listening position about 2.5 - 3 meters away and one nearer to a corner of the room.
The room size is quite large at 26' x 16' and really does need another sub.
At present there are areas within the room where you can feel better output but as this sub is so big (and ugly according to the wife) im restricted where i can position it.

I can see i may need a re-think here