B&W ISW-4 with grille removed

B&W ISW-4 in wall subwoofer


"A superb space saving idea. Traditional subwoofers need to be placed somewhere in your room on the floor, which means they can take up space and leave trailing wires. With this in wall subwoofer you can hide one of the most bulky parts of your home cinema system."



Those geniuses at Bowers & Wilkins always seem to come up with clever ideas that work both in terms of ease and in terms of sound quality. The B&W ISW-4 is one of two in wall subwoofers. This version directs its two 8 inch bass drive units directly into your room. Simply cut a hole where required and mount the provided back box into your space. Run any cabling you need through the wall from your AV receiver and then mount the subwoofer into the dedicated back box - please note that the back box is sold separately!

Once connected, run any room correction processing your receiver has to tune the subwoofer in and you'll have great bass without massive boxes filling the room. It's a little bit of work but does result in a very clean looking room.

Sound wise it is on a par with similarly priced subwoofers, although you may find some traditional solutions have a slight edge. However, we think the convenience of having a hidden subwoofer more than outweighs any minor detractions on sound. It's still fantastic and B&W have evolved a great sound from their bass systems over the years. Highly recommended if you need to save a bit of space.

This subwoofer is a passive subwoofer and as such you'll need dedicated subwoofer amplification to get it working. Bowers & Wilkins provide such an amplifier in the B&W SA250 Mk2. This amplification unit takes a feed from the pre outs on your AV receiver and then amplifies before passing via speaker cable to your subwoofer. The SA250 Mk2 can run one or two subwoofers so you'll only need one of them whether you are running a 5.1 or a 7.2 system (or indeed anything inbetween).

As always we give the very best deals so if you want to ensure you get the best, why not get in touch and let us see what we can do for you.

Important - this product may require additional products to work

The price advertised here is just for the subwoofer. You'll need a back box to mount the subwoofer into and an amplifer to run the subwoofer. B&W sell these items separately, or you can provide your own. Our recommendation is of course to use the B&W products as they are designed to work with this subwoofer.

Also known as: ISW 4, ISW4

Tech Spec


Model ISW-4
This product is collection only Yes


Speaker Type In Wall


Subwoofer type Passive
Subwoofer speaker type Forward firing


Subwoofer dimensions (W x H x D) 345 x 1406 x 86 mm
Subwoofer net weight 6.4 kg