Sunday, July 9, 2017

Happy Endings, but wait this never ends

A pleasant surprise discovery on Saturday was the modern-DAC-compatible low latency of the Denon DVD-5000.  And it has pretty good measurments too, though the distortion is just a tad higher than the DVD-9000 at 0.0017% (my measurement is identical to Denon's spec), but the noise is more than 10dB down at -111dB, and all the hashy looking upper octave noise is gone, so it looks to be the better sounding unit in present condition.  The DVD-9000 should have better noise as well as distortion, mine has some problem it looks like, though I now have a 2nd unit not yet tested, to be fair, subjectively I felt DVD-9000 to be my best sounding player (among the 4 "players" I have: Denon DVD-9000, Sony DVP-9000ES, Integra Research RDV-1, Pioneer PD-75)...and I never even bothered to listen to the DVD-5000 as a player I just immediately put it to work as a tweeter DAC, and there it was, possibly better sounding still than my Dac 19 even with the Krell, but I just never bothered to try it.

The low latency makes the DVD-5000 compatible with my other DACs in my multiway system.  RMAA was showing the same latency numbers for DVD-5000 as Dac 19 and Master 7, though in all cases the latency jumps around a lot probably because of the windows computer itself, and the dacs may have very little.  By ear so far it also seems to be perfectly compatible, though I do think I should do a very precise differential latency measurment with oscilloscope to be sure.

So, the DVD-5000 has been elevated to be the DAC for the Acoustats, for the moment, and I think it has less excess highs (including distortion and noise) than the DAC 19 and as nearly as much definition as the Master 7, a kind of budget Master 7, lacking balanced outputs but with the same dual differential 1704's.  (DVD-5000 actually measures better by RMAA than the Master 7, which I'm hoping will get reversed by repair of the Master 7, after all, the specs of the Master 7 are better.)  Reducing excess highs is also especially helpful now that the Aragon is being used for amplification, though I still think I'll chose DVD-5000 over Dac 19 even with most other amplifiers.

Spectrum of DVD-5000 (green) vs Dac 19

And now after a month of testing DACs, amplifiers,  and speakers, often only playing one channel at a time or shutting down for the night after 45 minutes...I finally have a fully working system back online that can play all day and night in stereo at any reasonable level.  I even put the super tweeters back online, but it took many hours of readjusting them to achieve, once again, the magic sound, that's just there, which I can finally relax and enjoy.

Anyway, I'm sure it wasn't this way before (and it may be measurement error from my now almost 2 year old phone, or it could be the Aragon vs Krell difference on the Acoustats) but the RTA app is now showing the Acoustats considerably rolled off above 16 kHz.

I could conveniently fill in all the missing highs with my supertweeters.  Or so I am often tempted, and I tried again this time for several hours with many different tunings.  But it doesn't work.  A metallic sound emerges, I think my supertweeters are damaged.  They play OK so long as not stimulated much below 18 Khz.

That's what I've long done, actually crossing over at 19.3khz.  But I've often been tempted to use only one LC filter (12dB/octave).  That also doesn't work, the metallic sound can come back at high enough levels.

What does work is 3 HC filters, for a total of 36dB/octave, starting at 18,811 Hz, or at least that's the magic combination I'm using now.  This doesn't fill in the 16+Khz gap, but the 20kHz band is almost up to the peak level around 1kHz, and there's not too much depression before that.  I'm really only adding to the two highest bands shown (as I can see from other measurements), and there's just a tiny bit of audible mist coming from the super tweeters, but that's enough to make them worthwhile.  They don't actually seem to add to the highs, they soften the highs by the tiniest amount, but add definition to the bass and eliminate beaming.  In short, they push it into hologram territory.

(Depending upon source, there is also info above 20kHz.)

I tried using the Dac 19 on the amp driving the supertweeters, but decided it could actually make some pops (though before it seemed perfectly behaved on sampling rate changes and muting).  So I switch to using the Emotiva Stealth DC-1, I now have 2 of them, one for the subwoofers (which take full advantage of the balanced connection, and the subs are now on a different AC circuit so that helps) and one for the supertweeters, with the DVD-5000 handling the midrange.  This also provides guaranteed identical latency (with time delay adjusted elsewhere to account for the physical position of the speakers).  The

This and some more adjustments to the bass (I added a 2.5dB rise at 20Hz gradually decreasing to 0dB at 63 Hz using the graphic EQ feature of the DEQ), and I'm playing Dylan and the Doors LP's at 99.9 and loving it.

It's spooky good again, and it's a good audiophile talent to be able to turn the combination of units at hand into something that way (which I heard, for example, John Iverson was extremely good at, in has days as a speaker designer, he showed workers how to get the crossovers working to make imperfect drivers sound great).

There are also the times, and audiophiles who just give up, sometimes for months or years, not playing anything anymore because the sounds of memory can't be achieved again.

Update: On axis, the Acoustats are much flatter and don't roll off as much.  The graphs above show listening position approximately, I tried to better guestimate ear positions and powered the right speaker (one with all film caps...though the other hasn't measured different) only, and essentially produced the same results.

Right on axis, the response looks flatter, but it sounds peaky to me, I much prefer the gentle rolloff of the off axis, which I understand is the typical subjective respose and may have some psychoacoustic merit...our relationship to sound producers is generally not on the the axis of best HF response.  Plus, off axis, there much less change with slight change in position, and most off axis positions have excess rather than too little highs, extending audibility throughout my little house.  And then there's the supertweeters, which add to the axis independence also.

Though to be fair, I might prefer a bit less rolloff, or in the present setup, less dip just below 20kHz before the super tweeters kick in.  But making that better integration, removing the 18kHz dip, would require much work...possibly going to a 4 way system???

As is, Friday night playing Side Two of Dave Grusin's Night-Lines at 95.8, it sounds absolutely fabulous (more fabulous than this disk may deserve but anyway).  I'm sure I might prefer a different amplifier or set of speaker adjustments, but maybe not so much a dac.

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