On wall speaker questions

I am replacing Eosone RSF-1000 towers and need help picking or making on wall speakers for next to my 59" plasma. It is mounted above the fireplace on the brick wall. It is not as thin as the led tv's now so I have about 3.5 inches of depth compared to how far the TV sticks out from the brick. I always wanted the Definitive technology mythos xtr-50's, but with such small drivers there seems to be a considerable advantage to a diy approach given my added depth. The Definitive have a 1.5" depth, but that is not crucial in my case. I would prefer to buy 3 or make 3 identical speakers.

I have looked at the options and I feel the low end frequency response is very poor. 120hz is about the average, plus I see they offer 3.5 or 4" drivers max. Since I have a little more depth to work with I might consider a DIY project with some larger drivers for a better blend with the sub. I am having trouble finding any 5.25" low profile slim speakers to use though.

Has anyone a suggestion for such a speaker or don't they exist on the home audio market? I have seen plenty of car audio slim speakers. I have some Stereo Integrity TM65 MKiii speakers that are 2.3" of depth, those would liven it up compared to a 3.5" speaker I suppose. I am a car audio guy so don't be too harsh.

Another question, with it being a Plasma or maybe down the road LED TV, is there any reason for a magnetically shielded speaker setup?
 
This is what I have to work with. The speakers are going to be mounted to a steel plate attached behind the TV mount so I don't have to drill more holes in the brick. They need to be about 4.5" in total depth and 29" long. I thought about raising the TV so the center channel can mount underneath. When I use the wood insert I move the center off of it, not ideal. I like those Peerless shallow 5.25" speakers, but adding up 6 of those, 3 large format tweeters, passive crossovers, wood, grill cloth and duratex I don't think I will be able to match the Definitive Technology xtr-50's for around $550-600. I wish there was somewhere I could demo them. What would you do? JPEG_20211014_104832_2575453855472988661.jpg910def.1.jpg
 
What you should realise is that as sound falls off the edges (so to speak) of the speaker, the wall behind it increases the effect. That's why keeping the frontage flush is something that can work.

However if you must minimise that you might consider using the screen on one side and rounding away towards the wall on the other.
 
I am confused, I want to emulate the look and performance of the Mythos speakers pictured with a diy approach with those 5.25" speakers mentioned above. I want the look very similar and sized mentioned. I have looked through the threads and see a crazy triangle open front design with it looks like a single paper cone driver.

The other one is square and won't work astetically. I am looking for something about 8" wide max and 29" long with a depth of 3.5" mounted on the brick which would be flush with the TV. Remember I am a total noob and I want to stick with a clean design not obnoxious.

Pictures of what you are recommending I would understand. The pizza box design is not what I am looking for.
 
I see, we may be at crossed purposes because when you used the words 'on wall' in the thread title this may have triggered our knowledge of how this unique situation affects acoustics, and what this means for speakers.

But.. if you are looking for a simple box shape that is 8" x 29" x 3.5" and has 3 midwoofers, a tweeter then 3 more midwoofers then we need to forget the wall part of it and calculate the volume of the box and find a midwoofer that is comfortable fitting into a sixth of it..
 
Reading your post #10, Ken, It would appear you want three identical slim enclosures, each containing two 5.25" bass units and one tweeter - correct?

If you give the external dimensions required of an enclosure, someone may be able to deny or confirm whether a pair of Peerless gbs-135f25al02-04 woofers would operate sucessfully within the enclosure.

I presume the tweeter would sit midway between the two bass drivers?

https://www.farnell.com/datasheets/2579637.pdf