You are probably going to get a lot of opinions on this thread......so here comes mine.
While I agree with many of the things Andrew said, you have to be realistic about what you are trying to achieve and how much you want to spend.
1) if you don’t have headphones, don’t bother with buying anything else or shooting your room with a sine wave until you have a basic decent pair of phones. Spending about $100 US will get you a basic pair of closed back phones from Sony, Audio Technica, AKG or similar manufacturers.
Cross referencing with headphones is the cheapest way to get a different perspective on ambience and bass extension. it’s not great for panning necessarily unless you like LCR mixing.
A lot of people mix in weird rooms at low volume and cross reference against commercial tracks with monitors and phones and their stuff sounds great - so after basic gear it’s definitely the ear not $$$$ of gear.
2) if you have that then bass traps are likely the next best money you could spend but it helps to understand what you are trapping.
Most rooms are rectangular. With parallel walls and usually hard surfaces (gyp-rock or drywall). They usually have a lot of flutter echo in the higher mids and high freq. this is easily tamed by using fibreglass or roksul or similar panels which are available from a million places in the US like GIK acoustics.
So these kind of panels take flutter echo really easily but as long as they are double thickness (4”) and placed across any of the 12 right corners in a rectangular room they will take away a lot of bass buildup.
Most people orient their monitors down the long dimension of the room. Say you have a room that is 3m wise and 5m long you put the monitors in the corners on the short side and they fire down the 5 m length of the room. Monitors on sand filled stands (easy to make with basic building supplies) with the monitors 0.5m off the walls will be a great start. Most people have 2-5bass traps they put in the corners behind the monitors and then on the first reflection points on the sides and the end wall of the room behind their computer monitor. Most people’s rooms end up with a dead end where the monitors sit and a live end behind them that is farther away and doesn’t effect things too much but helps with a little room ambience and it doesn’t sound like you are mixing in a vocal booth - like not totally dead.
Anyways - like I said it’s relative. You aren’t mixing million dollar records. Basic monitors and headphones mixing at medium volume for tone and super quiet for level balances will get you a really long way especially if you reference against commercially available recordings.
Good luck!
In case you were wondering - yes I bought bass traps and probably have 9 of them in my room. They were a great investment (like spend $600 US on them years back) but having been producing for a while now I don’t even feel they are essential. There are so many great pieces of software out there like iZotopes Tonal Balance plugin that really help you get things balanced without having to mix loud or spend $$$$$ on expensive monitors, lots of room treatment, or software that accommodates for your particular room weirdness. Naturally if you have tons of €$$$$ burning a hole in your pocket that stuff is all fine.
), so this is all quite new and exciting for me. The room at my disposal is pretty small (L: 3.1 m; W: 2.85 m; H: 2.55 m), and unfortunately not that far off being cuboid. I gather this is not ideal.
