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I've been visiting several well know acoustics forums for years, and studied them and some written literature intently before designing my studio in 2015. I planned it to the best of my ability at the time and built a significant number of DIY bass traps. Those and some thinner panels from my previous apartment room studio formed the bulk of the acoustic treatment. A friend with considerable expertise helped with the final positioning and optimizing of the panels.
Over the last four years I've made incremental improvements, some based on theory learning, some from experience recording, mixing and mastering there. My fascination and study with acoustics continues, and I now feel ready to make some bigger improvements. I'll detail the current state in this post, and put my plans for improvement in subsequent ones in this thread.
The studio is on the second floor of our detached house. We moved here in 2015. It's a modern timber frame construction with a pleasing block cladding, built by the previous owner (a professional builder) for his family. The studio is in the "attic" and the walls are part sloping along one dimension. I quoted attic because it isn't really - the house was designed and built this way, so has proper sized stairs, landings, doors and so on. Even before treatment the studio room had appealing acoustics.
Before acoustic treatment;
The house is at the bottom of the "U" in a town cul de sac. The studio faces south onto our garden, then a very dense wooded area. The wooded area is dense with tall trees and undergrowth. It's really nice to look out on when working, especially in summer when the leaves are all present. Beyond that is a road, then more wooded areas and some housing. After that it's pretty much park, farms and countryside. South is at the top of the page.
My initial plan was to to use it for composing, writing arrangements and recording single or small groups of instruments and vocals associated with this. Guitars, strings, horns, light percussion etc. This comprised most of my work at the time.
Not long after completion though, a jazz composer I had played bass for asked if he could record his band here. Drums, sax, guitar and bass, all to be recorded live. I figured we could do it all in room 1, gave our neighbours advance warning of potential noise and promised them it would end 5pm at the latest. I spoke to them the day after, and happily they didn't hear a thing. In our garden you could hear there was a band playing, but it wasn't bad at all.
Since then I've been blessed that many other people have recorded, mixed and mastered here, and my love of music production and recording has grown with the studio. Much of my work in the last few years has been in producing, recording, mixing and mastering. Most of it comes by word of mouth or musical associations from my bass playing or arrangements. I've constantly developed the studio and my skills to do the best I can for these projects.
The vast majority of work goes on in room 1. Writing, arranging, recording, mixing, mastering. I often have production input into recordings, and being in the same room as the musicians & songwriters is hugely beneficial.
Dimensions of this room are 4.95 x 3.5 x 2.29m. Here's the current state of acoustic treatment;
The beige panels are mostly 600mm wide, open frame and filled with 100mm thick Rockwool RW5, mineral wool of 100kg/m3 density. In retrospect perhaps not the best choice for bass absorption due to high gas flow resistivity of ~60 x 10³, although there are some who reckon it's ok at 100mm thickness. These charts that show reasonable absorption properties in the low end;
The grey panels with blue trim were from a large TV studio that was relocating. They are 1080 x 600 x 45 mm perforated metal faced and filled with absorbent material. The have an open back, and the studio had them fastened to a wall butting up against each other. Presumably some sort of resonant properties were in force in that configuration. I haven't used them that way yet, just covered the open backs with cloth and hung them on the walls and ceiling, some with an air gap.
The biggest and loudest entity so far has been a six piece rock group, initial tracks recorded with them all playing at once. For this I routed cabling through the eaves into room 2 to gain an additional room with decent sound isolation. The landing is similarly routed for "drum room mics" and is also useful for guide vocals. There are XLRs to the room below, which I've employed to isolate a large bass guitar cab. A guitar cable is routed this way too so the bass player can stay in room 1 with the drums. All these rooms have returns, sends and talkback / listenback from the main room for recording monitoring. It's a nice system that works really well.
Room 2 is a guest room, and usually used for relaxing and getting a cup of tea or what have you in between takes during sessions. In practice it's only been used for recording by larger groups or when there is a requirement for serious isolation between sound sources. I use gobos to make temporary acoustic treatment in this case.
I've recorded a large range of instruments in room 1, the quietest a gently bowed violin with a Blumlein pair of ribbon mics 4' away. Loudest is drums, recorded occasionally, perhaps once every two months. I keep these to 9-5 hours as much as possible.
For an idea of how and what, on my website there are photos of the studio and some sessions in progress, and also some videos and audio of music made there;
https://www.jenclarkmusic.com/producer/music-studio/
The walls are plasterboard. The floor in rooms 1 and 2 is real wood about 16mm thick on top of standard floorboards also about 16mm thick. Most doors in the house are sturdy and heavy with a solid plasterboard core. On the main studio door, I've added "batwing" perimeter seals on the sides & top and a drop leaf seal on the bottom. It's pretty effective. The wall sockets are mostly flush mounted into holes cut in the plasterboard. For further sound leak control I intend to fill or cover up these holes with 18mm MDF and mount the sockets in surface pattress boxes instead.
The balcony from room 1 is a Velux roof terrace, triple right handed;
https://www.velux.co.uk/products/roof-w ... of-terrace
I've not been able to determine which version of glazing is installed, but they are double glazed and seem to have quite effective acoustic isolation. It's likely to be either the 35 or 37dB version. There are vents at the top of each window set that can be opened or closed. Good for air circulation. It's pretty quiet with them open, very quiet when closed.
I sent pink noise through a bass amp on a riser in the centre of room 1 pointing towards the windows / balcony. It measured 105dB at a distance of 1m. All measurement C weighted, slow. Levels in some relevant adjoin spaces were;
Floor 2:
Studio Landing: 79.5 dB
Room 2: 62 dB
Floor 1:
Rooms below studio room 1: 70 dB
Rooms below & across from room 1: 54.5 dB
Room beyond that: 47dB
Ground floor:
Living room (below room 1): 56.5 dB
Kitchen (across from room 1): 55.5 dB (only just audible)
Garage (converted, built in to house): 46 dB (only audible if you really really concentrate and seek it out)
Boundary to neighbour: 61dB
I also did a test at 98dB in the studio, which went to 66dB on the balcony.
Ambient level in most rooms is 42 dB. Ground floor is a little louder, especially the kitchen. The garden was about 55 dB in utter stillness, which wasn't very often. Most of the time there is bird song, distant traffic, wind in the trees, and general neighbourhood noise, and the boiler coming on or what have you. Anything of that type was pretty much comparable to the 105dB source.
Some practical observations from over the years;
- I mix around 80 dB, which isn't heard at all in the rooms of the ground floor, and only in the rooms directly under room 1 on the first floor.
- Drums and brass are the only instruments audible in some rooms of the ground floor. You don't hear them at all in the garage.
- With a full rock band playing, drums in room 1, guitar and percussion in room 2, you hear nothing in the garage.
- I played a snare drum track at "actual volume" through some monitors in room 2, and listened in our garden to the North of the house. You couldn't hear anything.
In a nutshell: in terms of sound transmission, the current state is working.
Although the diagram says "live" room 1, it's really more of a control room with a large booth at the back. My understanding was that the room is too small to give a useful diffuse sound field for recording, so I designed it to reduce unwanted room sound influence and nasty specular reflections. For recording I tend to place the musicians and mics at back of the room, which is very absorptive. The wooden floor and windows at the front ping back a bit of ambience. I can reduce this with a cardioid mic, or bring it in a bit more with a figure 8. Sometimes e.g. for acoustic guitars I put up MDF panels to get some reflections back.
The acoustic is dry but very pleasant. The vast majority of people really enjoy it. Entrance is through the house from a suburban type cul de sac, then the hall and up the stairwell which is quite reverberant. When you enter the studio there's a sudden change of sound environment and view through the glass bay onto the sunny wooded area. It really is sudden and dramatic - a bit like when they walk into the holodeck on Star Trek! It really helps people get focused into the mood for making music in a professional way, and still catches me by surprise too ever now and then.
The large glass area acts as natural bass trap. The angled section reflects sound downwards then hopefully more or less into the insignificance / reverb zone. The vertical panes don't seem to cause much of a problem in practice, and it's easy to put 4x2' baffles on their ledge if they do. We tested drum overhead recordings with these baffles and without. There wasn't a huge amount of difference, just a tiny bit more ambience without them, and it was actually very pleasant. So I keep the panes clear now, apart from the middle vertical one behind the computer monitor.
There are two water based central heating radiators in opposite corners: a mixed blessing. They ring and are very difficult to dampen down, and interfere with the placing of corner straddling bass traps. But if they weren't there they would have to be somewhere else and be more annoying and conspicuous when boxed in. At least they are in "dead space" in the corners. I didn't have time to box and vent them in properly in the initial design, but will fix it on this iteration of improvements.
Running out of attachment space - I'll continue in the next post.
There's a 600Hz issue suspect SBIR, but I can't really fit any absorption behind speaker. 
And to be even more honest, I've never seen anyone actually mount their speakers like that.