Monoprice Monolith In-Wall Subwoofers

One home theater speaker that is fairly rare is the in-wall subwoofer. They are a fairly niche product but that’s not going to stop Monoprice from rolling out a couple. Enter the Monoprice Monolith M-IWSUB8 and M-IWSUB82 in-wall subwoofers. Let’s take a closer look.


Both the M-IWSUB8 and M-IWSUB82 in-wall Monolith subwoofers from Monoprice feature 8″ drivers. The model names pretty much tell you everything you need with the 2 at the end denoting the dual drivers of the M-IWSUB82. The differences between the two subs are few including the performance. Both are rated down to 36Hz at -3dB. The dual-driver model just promises more output.

Both Monolith in-wall subwoofers feature paintable magnetic grilles and multiple mounting tabs. There is an included 120Hz crossover that can be disabled by adjusting a jumper on the back of the speaker. As most will use these subwoofers with an AV receiver or amplifier with their own crossover, this is a fine solution.

The M-IWSUB8 and M-IWSUB82 in-wall Monolith subwoofers from Monoprice share nearly identical dimensions except for the height. Both are 10.8″ wide (grille is 11.9″ wide). The single driver M-IWSUB8 is 12.2″ tall (grille is 13.3″) while the M-IWSUB82 is 20.4″ (grille is 21.3″). Regardless of which model you choose, they should fit nicely inside a standard 16″ wall bay.

What You’ll Need

These subwoofers are so new that Monoprice hasn’t released manuals or installation instructions for the M-IWSUB8 and M-IWSUB82 in-wall Monolith subwoofers. There is no back enclosure so you’ll want to know how much space in the wall the subwoofers actually need for optimal performance.

Of course, you’ll need an amplifier. No, you won’t be able to use your AV receiver to power one of these. But the 91dB (2.83V@1m) sensitivity and 4ohm minimum impedance should make finding an amplifier a breeze. Just take a look at this graph:

We have no idea why Monoprice included the entire frequency range when these subwoofers are never really going to play higher than 200Hz or so. But they did. If you look at the left side of the graph, it is clear that these subwoofers present a very easy load. From their -3dB point (36Hz) up to 80Hz, the impedance is well above 4ohms. No need for massive amps here. A nice budget amp will power these no problem.

Our Take

It is no secret that we aren’t fans of in-wall subwoofers (obviously). Our objections are mainly because in-wall subwoofers are usually overpriced and they underperform. At $399 for the M-IWSUB8 and $599 for the M-IWSUB82, these certainly aren’t overpriced. While extension not much lower than 36dB isn’t exactly exciting, it’s about what we expect for an in-wall subwoofer. If you must hide all your speakers (and hiding a real subwoofer isn’t an option), the Monolith In-Wall Subwoofers from Monoprice at least don’t break the bank.

Check out the M-IWSUB8 here and the M-IWSUB82 here.

Leave a Comment

Your email address will not be published. Required fields are marked *