I was thinking along the lines of this which is similar to what I already have but would be on the ground floor (concrete floor/brick wall) instead of second story suspended floor and plaster board walls.
The problem is the size of the window, being almost the entire length of the wall behind the listening position. Windows can of course be treated (with curtains and blinds) but will only partially mitigate their deleterious effect. The good thing about your room is that you are able to move the listening position away from the rear wall and experiment to avoid the peaks and nulls of standing waves.
You will always have first reflections but a large room allows you to pull the speakers away from side walls and therefore delay the arrival of first reflections at the listening point. This is also why higher ceilings are good.
First reflections from the floor can be partially mitigated by carpets and rugs. Side wall first reflections can also be partially treated by positioning furniture in an effort to disperse first reflections. I have a large canvas painting on the wall behind my speakers.
These measures will never be as effective as purpose built room treatment panels/boxes but I am simply not prepared to go there.
Yeah have to be very careful here. If you overdesign it to perfection it will sound awful for music but great for surround.
The reason is, a perfect room with no perfectly parallel walls, damped non reflective construction etc. makes it sound like you are an ant trapped between giant headphones. It’s the imperfections of the room that actually create the live in the room sonic illusion.
With surround, the goal is to delete the room and put you where the action is.
With stereo, the goal is to put the band in your room.
As such, you need to choose a primary goal and aim for that.
I’m in the middle of a house build and got to design my own room. Nothing stopped me from going to no compromise extremes but I set some rules for myself:
Primary goal is stereo.
Room must double as living room. I don’t want to be exiled to a lonely listening room. So it has to not look like a listening room.
Surround system also used. ATMOS 7.2.4 all in-wall speakers. Stereo is visible, surround isn’t.
Wall cavities filled with rock wool to prevent plasterboard resonances.
several smaller windows rather than one big reflective surface.
260cm high ceiling. Roughly 4.5x6.5m dimensions.
Wall to wall curtain box on the wall where TV and speakers are located. No window on this wall but for serious sessions I can draw the curtains shut behind the main speakers but in front of the TV.
Those are pretty much the dimensions of my lounge/listening room (2.3/4M ceiling), my speakers backing to the glass end (doors and window, with about 1m of wall between them).
As already said, ceiling is ‘low’ and square is generally awful. I’ve part improved this by using tall Kallax units to create walls near the speakers, creating dimensions 5M(w) x 6.5M(l). This seems to help.
When talking to GIK, they don’t seem to see glass as a major issue, as it’s porous (in relative terms) but standing treatment panels behind the speakers (in line with them, plus on the rear wall element) helps no end.
I’m also fortunate that I have 3 doorways, 2 of which I leave open, so as to prevent the room getting pressurised.
My speakers (to baffle) are ~2.35M from the rear wall/glass and the optimal seating position is (to centre of chair) ~ 1M, with treatment/panels in behind.
Well a few years back i decided to build MY perfect listening room. But rather than try extending the house i started from scratch with a detached room so i had full control of its design.
When designing this my final goal was for a room that would be for music and have no pretence to be a living room. I wanted a room that would allow me to recreate as near as realistic as possible whatever the source was , be it studio recordings , live theatre , small club and outdoor recordings. Not easy to do but I do believe i have achieved this.
22 ft long x 15ft wide x 9 foot ceiling height. Insulated concrete floor , all walls lined with acoustic plaster board , ceiling of double thickness of acoustic plasterboard. Own mains supply and specified mains cables/sockets.
Designed for symmetry and planned for full acoustic treatment. Did a lot of research into treatment with help and advice from GIK , Denis Foley [Acoustic Fields] and Eithan Winer [RealTraps]. One thing i did find is that even these experts do have different opinions/ideas on treatment. So the final result must allow for personal preference.
Final treatment comprised of 34 GIK panels . A mix of full range , range limited bass traps and diffusion plates.