Genelec 8040 nowadays. Used Alesis M 1 acive earlier and now know why they are bad.
braunie
That’s good to know, the Alesis M1 are the best nearfields I’ve heard so there’s much more to experience 
So it wasn’t BS then. Cool 
Yep… you know… just trying to keep it focused.
BTW - I’d like to more about the soffitt mounting in terms of construction. How do you prevent the whole front wall from becoming a resonator? I know its a great method but I’ve never understood how or why.
Yup. Sound nice them M1’s…but…everything below 200 Hz is too sloppy - guess due to fact that they are trying to get too much from reflex port. Huge phase problems and they are too bass heavy. In upper midrange they are too forgiving - distorted guitars can sound really nice even they sound harsh in more revailing systems. highs are nice thou’. Just my 2 cents But sloppy is the word. and due to low wattage they distort fairly easily.
braunie
Mount the speakers on a heavy weight ( 4 times the weight of the speaker ). Then decouple the speaker+weight mass on an elastomer ( such as Sylomer ) and sit that on the speaker mounts. The mounts should be extremely solid.
you are basically creating a ‘mass-spring-mass’ system ( same as room within a room on a floating floor ) where.
So mass1-spring-mass2 is
mass1 = speaker + weight
spring = elastomer material
mass2 = earth
This ‘mass-spring-mass’ system has a resonant frequency which should be calculated to be ( preferably an octave ) below the lowest reproducible frequency of the your speakers. That’s becuase you get maximum transmission at the resonant frequency and progressively more isolation as you increase the frequency above resonant.
hth
So the speakers are isolated from the wall structure… in theory. It seems like you should still get some resonance off the front wall. It also seems that, by not tight fitting the speakers to the wall, you would be creating a port which would alter your frequency response curve.
Not to mention… What if you decide to move them a few degrees or inches? 
SOL
I guess I just see it done WRONG more often than not. For example…
This guy is just building boxes or shelves into his wall and calling it soffit mounting. Seems like a bad idea…
Depends upon the resonant frequency of the wall
It also seems that, by not tight fitting the speakers to the wall, you would be creating a port which would alter your frequency response curve.
Not in practise. you can get a small resonance in the gap between the speaker and the soffit enclosure but you fill it with rockwool to dampen that. You will get a frequency response change by soffit mounting anyway and it’s a desirable one. acoustic energy ( especially bass ) that normally projected backwards is projected forwards. the increase bass response means you can EQ this out and ergo your speakers have a lot more headroom.
Not to mention… What if you decide to move them a few degrees or inches? >
Well that’s tough tittie. Most people design the speakers in an equilateral triangle to the listener
I guess I just see it done WRONG more often than not. For example…
This guy is just building boxes or shelves into his wall and calling it soffit mounting. Seems like a bad idea…
It’s not a ‘bad’ idea, but it’s not as ideal as it could be. But it’s a lot better than no soffits. His wall looks pretty solid and hopefully he’ll cover it with enough layers of plasterboard ( sheetrock )
I made my soffits with enough room to place decoupled concrete filled wooden boxes in the bottom off …
You could build the holes bigger than needed and move the speakers around, as long as you back fill and plasterboard at each move!!! or just get it right first time
The front wall should be designed not to resonate by making it as solid as possible.
As PW says, the benefit of soffit mounting far outweighs any disadvantages
Or build solid soffit walls that can move for adjustment ( using hinges as you’d see on a nuclear blast bunker door )
The front wall should be designed not to resonate by making it as solid as possible.
Yup but sound still travels through solid objects really well … put your ear on the tracks and you can hear the train coming from many miles away
Double yup but massive things take a lot more to get them moving in the first place
Except at their resonant frequency …
Genelec 1019A http://www.genelec.fi/tuotteet/vanhat-mallit/1019a/
Avantone Mixcube http://www.avantoneaudio.com/active%20mixcubes.htm
Unless damped effectively unlike this more modern example!
Synchronous Lateral Excitation