Room Characteristics
As a home/project studio, your room does not need to be anywhere near as 'correct' as a professional commercial studio.
It does, however, need to be pretty neutral, and not too reverberant.
A commercial studio will purposely design a room a specific shape, from day one and build it with acoustic being the main priority, your spare room however, does not have this luxury. Hence this tends to cause a few problems when it comes to using this standard room as a studio.
The two main problems that are often encountered are:
- Standing waves/modes
- Reverberant character/response.
The most important thing to be able to do in your room is to listen to music accurately, and be confident that the room is not colouring the sound that you are hearing too much.
Without spending a small fortune, it is usually impossible to make a perfect room. We can however drastically improve the response of a room relatively cheaply.
Identifying the problems
A great place to start when seeing how your room is sounding is to simply listen to some of your favourite music, whilst walking slowly around the room. Listen very carefully to the different elements of the music, especially the bass.
As you walk around the room you will probably hear the bass frequencies getting louder and quieter in different spots around the room. Remember where these are, as they are probably caused by standing waves and we will look at a few ways to remedy these in the next section.
Also try clapping loudly whilst there is no other sound in the room. Listen carefully to how the should of the clap 'rings out'. If it rings for a longer time than expected, but is smooth then the room is too reverberant. If the sound 'flutters' back on itself then there is a problem between some parallel surfaces that needs to be remedied.
A more accurate way of determining problems is by listening to tones at 100Hz, 1000Hz and 10,000Hz around the room, and listen for peaks and dips in the volume of these frequencies.
If you are lucky enough to own a spectrum analyser, or can borrow one, this is the best way to measure the response of a room. Play some pink noise through you speakers and measure the frequency that is actually being heard in the room.
Possible solutions
At this level most problems with the acoustic response of a room can be resolved by a mixture of absorption and/or diffusion.
Absorption
Absorption works by 'soaking up' sound. Absorbent panels or structures are placed in the room at strategic points to absorb either specific frequencies, or a wide range of frequencies.
Diffusion
Diffusion works by dispersing sound around the room in a random direction, to eliminate standing waves and flutter echoes.
Acoustic treatment designs
There are a huge variety of different acoustic treatment designs, many of which are explained in a lot of detail across the internet.
Try these sites to start off with:
http://www.ethanwiner.com/basstrap.html
http://www.soundonsound.com/sos/jul00/articles/faqacoustic.htm