No, I haven't recently changed the cables in the rear.
Some more information about the problems I've been having...
The top attachment here shows the unfiltered curve. As you can see I have a big dip between 30 and 40 hz. The sub is currently in the front right hand corner of the room. The only other location for it is a little further left near the right hand speaker, or somewhere in between. I have moved the sub around and still get that dip in my listening position, which cannot parctically be changed.
I have attempted to equalize according to Ayreonaut's house curve that he recently posted. I used 12 filters to produce the second curve attachment. That was my first attempt which began with transposing the curve upwards to bring the bottom of the trough to a decent level before making some pretty major cuts elsewhere. The filters are as follows:
Filter ISOFreq BW Gain
1 49 10 -35
2 31.95 3 -17
3 83 6 -15
4 68 5 -9
5 35.8 2 8
6 57 4 -10
7 97 10 -20
8 29.35 4 -4
9 33.65 3 -2
10 44.5 5 -5
11 78 2 -3
12 25 20 -9
As you can see, there are rather a lot of quite severe cuts so I thought I'd have a go at doing it again with fewer filters. The result is the two curves in my first post - the REW plot alternates between the two. The filters were as follows:
Filter Freq BW Gain
1 32 8 -12
2 50 40 -8
3 63 15 -9
4 40 5 +4
Could the inconsistency be due to filter 2, i.e. having a cut over a large bandwidth (40)? Filter 2 (sometimes) has a very positive effect on the curve as a whole with the large bandwidth. But it seems that the four filter curve is sonically unstable in my room :holycow:
The 12 filter curve seems to give consistent results. However it requires the sub gain to be turned up from about 10 o'clock (unfiltered) to 3 o'clock, which is nearly maximum! I am concerned the 12 filter curve has too many large cuts and will have a negative effect on the available headroom and sound of the sub.
I would appreciate any thoughts that you may have, apart from the rude ones. My wife is certainly having a few thoughts about the amount this equalisation lark
I expect that I need to try again and aim for fewer filters with a stable curve. One other question... is sweep the most accurate? The results seem to vary quite a bit for the different tone types, e.g. 1/6 oct versus sweep.
Thanks again
Al