My speakers are placed like this:
OK, there's your first problem. They need to be set up much better than that.
First, you have them the same distance from the front wall and side walls, meaning that all SBIR and comb filtering artifacts will occur at twice the amplitude, at the exact same frequency!
Like that, the frequency response will have a major dip at 106 Hz, a major peak at 53 Hz and 124 Hz, plus other peaks and dips at increasingly lower magnitude all the way up the scale, creating a comb-filtering effect (but probably not audible above about 2kHz). Sound familiar?
(Take a look at your current REW graphs....)
Next, the speakers are too far away from the front wall. For a small room like that, they need to be right up against the front wall. The room is not big enough for you to be able to get them far enough away from the walls, so they have to be right up against the front wall. That way, the SBIR dip moves up into the lower mid range, where it is a little less objectionable, and can be damped better with insulation behind the speaker.
Also, you have the speakers laying on their sides, which would be OK for a large room where you can have them a long distance away from you, but for such a small room, that's not a good arrangement. You are way to close to them to use that arrangement. As you move your head left-to-right, and front-to-back, your ears move closer-to / further-from the tweeters and woofers: your ears will always be at different distances from them, and therefore different timing. You cannot get a good stereo image like that, and your sound stage will be greatly skewed and distorted.
Also, your listening position seems to be in the wrong place. That needs to be fixed too.
So here's what you need to do get your geometry correct:
Set up your speakers standing vertically, with the tweeter above the woofer, such that the acoustic axis of the spekaer is 1.2m above the floor. The acoustic axis is the point from which the sound seems to emit on the front panel, and is on an imaginary line that joins the center of the woofer to the center of the tweeter, much closer to the tweeter. Your speaker manufacturer can probably tell you where that is. That's the point that must be 120 cm above the floor. You could put it a little higher, maybe 130 cm, to help reduce the artifacts from your desk, but no more than that.
Set the speaker stands so that the acoustic axis is 70cm from the side walls (so the speakers will be 113 cm apart), and so that the rear edge of the speaker cabinet is just touching the front wall (or maybe leave a gap of a few mm). Rotate the speaker inwards to an angle of about 25°.
Set up your chair so that your ears are 135 cm from the front wall when you are mixing normally, seated comfortably. If necessary, move the desk so you can work easily in that position.
Now set up a mic stand so that the tip is at the same height as your ears, and is located about 30cm behind your head, on the center line of the room. Adjust the angles of the speakers a little bit so that they are both pointing exactly at that spot (once again, I'm talking about the acoustic axis of the speakers: imagine a line poking out the front of the speaker from that point, perpendicular to the front panel. That's the line that must point at the tip of the mic stand.
That gives you roughly the right geometry for your room. Do a REW test with your measurement mic located exactly where the middle of your head will be while mixing, and post that. Do a listening test with music you know well, and move your head a bit forwards and backwards to see if there is a better spot. Adjust the speakers a little side to side (small steps!) to see if there is a better spot for them (keep them symmetrical, of course). When you find the best spot, do the trick with the mic stand again, so the speakers are angled correctly to point at that spot about 30cm behind your head. Do another REW test like that.
For both REW tests, calibrate to 80 dB for each individual speaker, so the combined level will automatically be about 86 dB. Do a set of three tests, every time: Left-only, Right-only, and Left+Right. Label them!
Let's take a look at those before deciding on treatment.
- Stuart -
