My current setup is composed almost entirely of in-wall speakers, with the VP180 being the exception. It just occurred to me that I could have gone with M5HP on-walls for the left and right channels.

Low frequency performance aside, would I gain anything by having on-wall M5HP's instead of in-walls?

You got a great set-up. The in-walls should be a bit more sensitive (check on the respective product pages) and they won't suffer from speaker-wall boundary interference like the on-walls or conventional boxes.

Having said that, I pointed out to you when you first started asking, that in-walls likely won't equal the soundstage and imaging you can get from conventional boxes. But, if you don't have the space, and you need everything to look clean, what you've done is the best option.

Interesting, didn't realize the in-walls were more sensitive. Conventional boxes are a no-go for me, sadly. I was curious as to whether or not bringing the drivers that 4" out from the wall might make a noticeable difference to soundstage/imaging.

NOOOOO! That will make things worse. Axiom worked very hard to optimize those in-walls. They are properly engineered for the best sound.

I can see what's happening, bman. You are finally understanding how amazing that v4 sound is...and you want to completely optimize it. Unfortunately, the vast majority of us have to live with limitations.

I wouldn't pull the in-walls out of the wall lol. I'm referring to the difference between in-wall and on-wall (the former sticks out by about 5/8", while the latter sticks out 4" and a bit).

I see. I very much doubt you'll hear any difference in soundstage and imaging. In fact, you'll get a cancellation notch at 3,378Hz...which you'll hear if you have the ears of Wolverine.

The difference between the in-wall and the on-wall would be negligible. The key is that the drivers are in front of the wall plane. Since our in-walls have the drivers slightly proud of the wall plane they work like on-walls. Having the drivers even slightly behind the wall plane is a big problem. We blind tested this during the design phase of our in-walls.

Thanks Ian. Any concern about my TV interfering with the M5's? It's about 5" to the side of the speaker, and comes out about 3" further from the wall than the face of the M5 does.

https://www.axiomaudio.com/boards/ubbthreads.php?ubb=showpic&id=1542

bman, that TV will mess with the "Early Reflections" curve. That curve is responsible for image width, stability and timbre and is taken at +/-40, 60, and 80 degrees across and 50 degrees up and down. Of course Axiom may actually take those curves at finer angles but the point is, that TV will interfere with the curves from 31 degrees all the way up to 90 degrees. It will also mess with the sound power and directivity curves.

You can see this if you form a triangle with legs of 3" and 5" and solve for the angle between the 5" leg and the hypotenuse.

I have no idea how audible this might be in your room.

Of course Ian knows best. For all I know, Axiom may have adjusted for the "TV effect" but I highly doubt it. Now if you had active M5 in-walls...well...maybe that TV effect could, to some degree, be compensated for.

Scratch what I said above. Now that I've had coffee, I can see I didn't account for the radius of the driver and the speaker frame. That angle is more like 19 degrees. So the TV will interfere with the Early Reflections curve but only from 70 degrees up. I very much doubt you'll be able to hear the difference.

I broke one of my cardinal rules --> No STEM before coffee.