Saturday, October 27, 2018

The Kitchen HT system sub now re-enabled for stereo

I mainly use my kitchen HT system to play stereo, but I have the two surrounds and sub to add in for actual 5 channel material.  I'm opposed to center channel speakers on various grounds, and I always use the appropriate setup which folds the center as a mono signal into the fromt left and right.

For stereo, I'd always used the "Direct Stereo" output of my Yahama HT-5790.  I measured this, and it clearly bypasses the digital conversions that the various HT modes require.  An alternate is "2 channel stereo" which does do digital processing for 2 channels.  The digital processing is clean except, of course, it introduces noticeable pre and post ringing, the kind that J Peter Moncrieff seems to be telling us is all fine and good.  (And all "objectivist" engineers also, I might add.)

So, using Direct Stereo, I have no "subwoofer" output, because the crossover is implemented in the DSP.

Recently I've been playing FM on the Kitchen Tuner because it attached to my roof level whip antenna which clearly surpasses all my other antennas (merely as a result of height, long I tested inside and it was worse than my indoor antennas).

After I moved on from the McIntosh MR78 with Modafferi Mod, which had a kind of steely, though clearly very high information, sound that was fascinating sometimes but not appealing and actually a bit tiring, I brought out the Sony 730ES (because it was most accessible in my conditioned storage building) and the sound is so much "nicer" somehow, combined with the much better antenna, it's somewhat intoxicating.

But what's always been noticeable was the kind of "miniaturization" done by the Kitchen setup.  This may be partly the almost nearfield location of the speakers, and similar factors.  The speakers themselves are the once Stereophile Class A Revel M20's, which go to 30 something Hz and cross over nicely at 60Hz, as I have always done in the bedroom.

I've always noticed the "heft" of the living room system playing FM, so preferentially even I play the Living Room stereo when I'm in the kitchen, even at the expense of an actual stereo image.  Appropriate somewhat to FM, it was the "concert is in the next room" experience, but like a real concert, instead of the table-top miniature in the kitchen.  Having the subwoofer for regular stereo, now adjusted pretty good, gives things the full size and heft, and even seems to be removing some of the steelyness from the tone--which might have been resulting from mismatch between extended high end and rolled off low end.  It may have been that lack of steelyness which I was confusing for the lack of definition in 2 channel (dsp) mode, much more than the digital resampling and DSP.

At various times I've played the subs, and though this speaker (an SVS 10" from the 2000's which was my very first "real" subwoofer and was a revolutionary upgrade to my bedroom system, replacing the McIntosh M22's I had been using as subs, but that was quickly upgraded to the SVS 39 inch 16 Hz tube). but in the kitchen it had sounded terrible, quickly invoking the "turn it off" reflex, so I guess long ago I had decided Direct Stereo was better and that was that.

But, I wondered, what if I just turned down the subs a little.  I had never really measured the system, or adjusted by measurement, or maybe I'd tried the auto adjust once and hated it, preferring my own manual "by ear" adjustments, notably using the built in level adjust test signals in the receiver, and balancing the different speakers and the subs by ear listening to the test signal.  This was set up before I had an always ready 1/6 octave RTA in my phone.

So I tried adjusting the sub level to get the flattest response using my standard noise source, Stereophile Test Disc 2.

And this required an astonishingly low setting for the subwoofer level.  After several days of readjustment and measurement and listening I've gotten to setting the subs at the low end of the second lowest mark on the level screen, with a 60 Hz crossover and "bass" set to "both".  As I was previously attempting to audibly match the level of the 1kHz centered pink noise signal with the signal in the bass on the Yamaha, I was setting to within the third highest mark.

If I set the "bass" to "swfr" it seems that the low bass disappears in "2 channel mode".  Im suspecting this is a bug in the Yamaha.  That's why I'm using "both," which I assumed would effectively use the bass as fill-in, and since I've set the back speakers to "small" they shouldn't get any bass from the "both".

What I really plan to do is use a behringer DSP to do the fill-in crossover and shaping for the bass, and I currently have a spare DEQ 2496 which I'm clearing the space for now.  Previously, way back in 2009 or so in fact, I bought an extra Behringer of the earlier vintage, DEQ 8020 or something, only 20 bit, and it was much more painful to use having few buttons and unintuitive to me displays, so the "equalizing the kitchen sub" project never got off the ground because I hated the equalizer.  Now I have a spare 2496 which I like (and will have to get another spare if I decide to continue this, or perhaps another miniDSP).

Now what I plan to do run the main speakers straight through, perhaps in Direct Stereo, and capture the extra LR line outputs in the back for the DEQ, which will then perform crossover, eq, level, and perhaps other functions.  However, I'll have to have a switched connection to the sub outs for multichannel inputs, which simply go straight through the receiver

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