The (last?) wrinkle

[Note: the "previous" post was actually finally completed days after this one.  The fine tuning done here still looks pretty good, but as I determined in the previous post, it will all have to be rechecked after I re-check the sub polarity and the sub delays, which will be the subject of future posts.  And the "delay bug" I describe here wasn't really a delay bug after all, it was a polarity inversion bug.]

Having worked around the strange left channel delay bug again, this time without messing the right channel, I'm back to trying to solve the weird lower midrange of the right channel.

I decided to keep the 133 Hz boost, because the resulting bass curve is the smoothest I've ever seen to 200 Hz, and with about the right room curve too (in fact, it looks as good as anything I could imagine).  But above that, and up to 2kHz, it looked like crap.

So I pulled out the notches above the 133 Hz boost until the 2.7 kHz cut (and more about that later perhaps...) and swept for the biggest peak.  Here was what the Analyzer spectrum looked like:

Right with lower midrange PEQ's removed

By the picture the 600 Hz peak looked biggest, which swept to be 599, so I set the closest notch at 597 Hz with 1/6 octave and -6dB.  That swept OK.

Then I added more notches at 833, 563 and 734 following similar process.  All along I looked at RTA's to get an idea of where the next peaks might be.

These are all different numbers, perhaps in part because I'm not starting with a boost near 1kHz.

Now the RTA was still looking pretty rocky, even rockier than before maybe, with the previous peaks all below 1kHz and the depressions even further down.  So I backed off each of the PEQ's, reducing the attenuation, until the peak was just at the 1kHz level.  Then the floor below the peaks was brought up too.  Sometimes I narrowed or widened the peaks (but I already chose narrow PEQ's when they were near depressed areas).  In the end, the 833 Hz cut no longer seemed necessary at all and was just depressing the two bars lower than 1kHz (and sometimes even 1kHz itself), which are still slightly depressed even without it.  I think it was largely subsumed by the 734 Hz notch for the 733 swept peak, which persistently showed up on the Analyzer as 710, seemingly one of the most persistent peaks.

The result uses only the 133 Hz boost (for the left panel anyway) compared to the previous 2 boosts and the 3 boosts used in the right channel.  Yet it looks pretty nice on the RTA and sweeps pretty nicely too.  (I don't even much notice the remaining peaks and depressions except at very very slow sweeps.)  There's still some lower midrange depression underneath the peaks but it's reduced as much as it can be without boosts.  The deepest valley tells me it needs a mere +4.5dB boost.  I swept that area and it seemed perfectly fine.  Perhaps there is some microscopic null but I didn't find it.  In sweeping everything is going up and down all the time, and it seemed no different there.

Right with new midrange filters

Just to show the improvement, here's what it looked like before:

Right with previous filters (measured day before)

Similar underlying shape but the tolerance has been cut at least in half by the new filters.  The earlier filters achieved a kind of artificial smoothness around 1kHz (but not AT 1kHz, which stuck out like a thumb) with a 3/4 octave boost at 1kHz.  I think it's better not to resort to such things.  But without it, that set of filters made 1kHz sucked out.  The new set of filters never sucked out 1kHz in the first place.  I think that HAS to be better.  I now wonder if I could do the same thing in the left channel, which has a 900 Hz boost.  But I don't think so, that was very carefully analyzed last month.  There was a deep depression there which carried 1kHz with it.  But I found no such depression in the right channel, only a peak which mysteriously went away when the other filters were applied.  Here are the new filters:

Right Panel PEQ's with 1 boost (PB1)