New EQ, Day 3

 After messing with the "Background" subwoofer EQ (again, last time was a few months ago) in the right channel, which I had been re-EQ-ing because of the new speaker, but the subwoofer hadn't actually change...

I decided I first needed to test and make similar changes on the left.  Measurements at the doorway and the table showed overly bulging response at 31.5 Hz.  It looked better cut back to zero as with the right channel.

But listening to Grouse, We Want To Be Loved, I decided this all made the deep bass line, which reaches down to 31.5 Hz, a bit less easy to follow.  So I restored boosting at 31.5 Hz in both channels in background to about +2dB.  (In the Serious Listening EQ, it's boosted 5dB because of suckout at listening position.)

Also, I could not confirm with pink noise any serious issue at 20 Hz, so I decided to reduce the cut there from -4dB to -2dB.

Current settings:

Left (last one adjusted)

20 Hz    -2dB

25 Hz    +2dB

31.5 Hz +1.5 db

Right

20 Hz   -2dB

25 Hz    0dB

31.5 Hz  +1.5dB

I think I might make both channels more like the Left settings, mainly boosting 25 Hz at +2.  Otherwise, the response IS falling at 25 Hz relative to 31.5.  Even with that +2 boost it is falling at 25 and 28 Hz relative to 31.5, but it is falling only ever so slightly at 28, which is a good improvement.

But it was too late to go any further.  Actually, once again, for best results I need to sweep this with an oscillator, or use a LF tuned keyboard (as I have done before).

Just like a down sloping high end, required because of the higher side reflectivity of small rooms, a slightly tilted up bass is generally required, it's just a question of how much and exactly where.  Finer adjustment of the hinge points may mean less boosting is needed to retain musical coherency.  There is probably some perceptual compensation for room gain, and the total room system output should invert that compensation.

Now, morning after, taking a look at the graphs confirms my memory and shows some other interesting things.  First, what it looked like with the old boosting (which I think was +5db, maybe only +3dB), in the kitchen doorway:

Left 2+2 with +5dB deep boost at kitchen doorway

Reducing the 31.5 Hz boost to 0dB but the 25 Hz boost at +2dB, it looked like a much flatter high plateau in the deepest bass (though I later re-raised 3.15 part way to +1.5 for musical reasons, not measured).

+2dB at 25 Hz, 0dB at 31.5

One thing overlooked here last night was the incredible broad depression from about 80 Hz to 300 Hz.

It's almost as if (and I have tried that at times) attempting to compensate for the lack of 125 Hz in the right channel by giving it some extra oomph in the other, which only "partly" works.

That looks like the next thing which needs to be investigated.  What the hell is going on at 125 Hz.?

With the background EQ, in the doorway, it's nice looking now in the right channel but part of a long depression in the left.