Hi there "clyde67", and let me add my welcome to RJ's.
A couple of things: First, one of the forum rules is that all images should be uploaded to the forum itself, not cross-linked to other locations. We did this because way too often we found interesting threads becoming useless when the linked images disappeared, and there was no way to revive them. So please upload your directly.
OK, about your analysis:
As RJ said, you really need an omni mic for good measurements, and you really do need to take repeat the test individually for each speaker, plus a third one using both if you feel like it. The reason for this is simple: the peaks and nulls in the room response for one speaker can be totally hidden in the peaks and nulls of room response produced by the other speaker. Each speaker can, potentially, excite a different set of modes, or excite them at different levels, or one speaker might have a reflection associated with it that distorts the readings, or it might by in a null caused by SBIR relative only to that speaker, or any number of other possibilities. Frequently the two graphs are different in a few specific areas, but pretty much the same in the rest.
In your case, it is hard to say what the issue is, but there is something major wrong with your measuring setup: I seriously doubt that your mic has such poor response as to roll off 40 dB above 10 kHz! And unless you are using pretty lousy speakers, it's unlikely to be that either. (What speakers did you use?) Lastly, its hard to imagine that you managed to so severely over-treat your room as to kill the highs to that extreme, especially based on the photo! My guess would be that it is your audio interface that simply cannot sample above 10 kHz. What interface are you using? Are you sure you had it set to a suitable sampling rate, such as 44.1 k, at least? Or maybe there is something else in the signal path, such as a poor quality equalizer, or amp, or something else that is grossly rolling off the highs?
I would suggest that you should look into that issue first, then repeat the measurements with a better mic, individually for the L and R speakers. And instead of posting the graph, post the entire .mdat file created by REW, so we can analyze it from a bunch of different aspects.
It would also help if yo were to post the dimensions of your room, and list the treatment you already have in there. Better yet, model it in SketchUp and post the model.
OK, on to a few things that could seriously improve the way you have your gear set up: First, get those speakers off the desk and onto suitable stands. If they are on the desk, they are undoubtedly causing vibrations in the desk itself that is totally messing up your perception, as well as early reflections that are screwing with your stereo imaging and frequency response (comb filtering, for example). They should be mounted on massive (heavy) stands just behind the desk, and even then should be decoupled from the stands with a pad made of Sorbothane, EPDM or neoprene. They should be set up so that the acoustic axis of each speaker is 1.2 m above the floor, and they should be toed-in (angled) such that the acoustic axes meet at a point about 25 - 45 cm behind your head, at an angle of about 60°. That puts your ears in the perfect relationship to the speakers, to get the optimum stereo image and sound field.
Next, get your speakers standing up vertically, not horizontally. The reason is quite simple: Your ears are on the sides of your head, not on your forehead and chin!
Even a slight movement of your head to the left or right will place your head asymmetrically in the sound field, with one ear being closer to the tweeter on that side and further away from the woofer, while the other ear is further away from its tweeter and closer. to its woofer. That means not only level difference, but also timing differences, all of which distort the way you are hearing the sound.
So your perception of frequency response will change subtly, as you move your head left and right, even a bit, or as you turn your head slightly. If the speakers are set up vertically, as they should be, then you simply do not have this problem: the relationship of each ear to the woofer and tweeter on that side remains the same, no matter where you put your head, and since the human sense of hearing is far less sensitive to direction in the vertical plane than in the horizontal plane, you'd need to actually stand up or crouch down with your head on your knees to perceive a difference. And by the time you move that far off axis, you'd be suffering a whole bunch of other artifacts way before this became an issue.
Yeah, I know that several speaker manufacturers do show their speakers being used horizontally in their manuals, and you even occasionally set such a setup in pictures of supposedly "pro" studios, but that doesn't make it right, and you can't fool the sound waves or your ears by showing them pictures! If you don't believe that this makes a noticeable difference, try it yourself: Once you get your speakers properly mounted on stands, try them both vertically and horizontally while moving your head side to side, and turning it, while listening carefully. You will hear the difference, I'm sure.
Finally, you are too close to those speakers. For each model of speaker, there's a distance where the individual sound fields from the various drivers start to merge and act together, as one single sound field. If your ears are closer than that distance, then you are not hearing the full range of sound produced by the speaker, and instead you are hearing the individual drivers differently and independently. I have no idea what that distance is for your speakers, but to me it looks like you are way too close to them. You will automatically solve that problem when you mount them on stands behind the desk, but it is something you should be aware of.
And one more point: You will need one of your absorption panels directly between each speaker and the wall (window?) in front of you, plus you will need to roll off the bass response of your speakers but about 6 dB, to compensate for the fact that they are radiating into half space, not full space.
There are probably more things that can be done to improve your layout, but the photo and your description don't provide enough info to go on!
If you provide more info, and repeat the measurements once you solve the problem with your measuring setup, then we might be able to provide more insight.
- Stuart -
That would be hard to miss...