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Soundstage Confusion

I'm in the midst of choosing a new amp for my listening room. Currently, I'm using a NAD M22v2. I just auditioned at home the LTA power amps, and really like their ZTOL40 Reference amp. I also have my faithful Pioneer SPEC-4 that I've had for over 35 years. My components:

Herron VTSP 3A(r02) pre amp
Innous Zenith MKII media streamer
Small Green Computer i7 Roon for DSP device
Audio Mirror Tubadour III SE DAC
Technics SL-1200G TT
Parasound JC3jr phone pre
Tannoy DC8Ti speakers

My room is 13.5x11.5x8.  I've positioned the speakers 34" from the back wall and 22" from the side walls. I've been futzing with speaker placement and my listening position for a while. I have no room treatment yet.

With the NAD and my current setup, I get a huge soundstage and room filling sound. The speakers disappear, but imaging is awful where voices and instruments are well forward of and outside the speakers, with little depth. With the ZTOL40, and no other changes, the main voices are centered between the speakers; instrument separation is clear and overall imaging is great; the soundstage is between the speakers; and the speakers do NOT disappear.  

To test soundstage and imaging, I'm using Chesky Records Jazz Sampler & Audiophile Test files that I downloaded from HDTracks.com, in particular track 10 Introduction and Left-Right Imaging Test, track 11 Listening Environment Diagnostic Recording, and track 12 Acoustic Soundstage (depth) Test. The ZTOL40 passes all tests with flying colors. The NAD fails them all.  I moved the NAD to my rec room system in place of the Pioneer amp. Soundstage is between the speaker; imaging is OK, and voices are centered.  Later today, I'm going to hookup the Pioneer amp to my main system and run the Chesky tests.  That should be interesting.

Before all of this craziness started, I had a different rack.  This past week, I replaced it with a Butcher Block 4 shelf rack. Before that rack, my speaker and sitting positions were slightly different; the NAD soundstage was between the speakers; and imaging was fine.  With all other things being equal, I'm finding it hard to believe that a different rack and/or an amplifier change could cause such a drastic change in soundstage and imaging.  Any ideas anyone?

 
128x128oldschool1948
noromance's avatar
noromance
9,825 posts
 
You’re testing too many things at the same time. I suspect the ZOTL amp is not yet burned in and that the soundstage will bloom in time. Take the rack out of the equation - put them both on the floor and re-test using same cables etc.
EDIT: So apparently, LTA say they burn in the amps for 168 hours. Re-test using normal music instead of test tracks. Yes, racks and mounting surfaces can have a huge impact.
millercarbon's avatar
millercarbon
12,531 posts
 
Out of phase? Ouch. Connected out of phase the sound would be utterly diffuse to the point of seeming to come from everywhere and nowhere and there would be no image, no soundstage, center or otherwise. OP clearly described imaging both times. Fifty demerits anyone even thought that was a possibility.

I'm finding it hard to believe that a different rack and/or an amplifier change could cause such a drastic change in soundstage and imaging. Any ideas anyone? 

There's a famous quote but I can't remember who said it and won't get it verbatim anyway but you all know it and maybe even are going oh yeah that one- its something along the lines of yeah I changed my mind (or position, or whatever) when the facts change I change my mind, what do you do?

You did a pretty good job making it perfectly clear that the rack and the amp are responsible for the difference. All you have to do now is let your mind agree with reality. Which I highly recommend. Banging your head against a wall is no fun, hurts, and doesn't do the wall any good either.

A nice relaxing method is to pull up my system, gaze upon its sublimely rational form meets function layout, and read the description. I got rid of the rack for exactly the reason you just noticed. But for whatever reason are reluctant to acknowledge. https://systems.audiogon.com/systems/8367
Or if you don't like my advice then listen to noromance who said pretty much the same thing. Only plus the too many things at once thing, which is another good one. But seriously, check it out, ditch the rack, the best rack is no rack, aka the floor.
oldschool1948's avatar
oldschool1948 OP
502 posts
 
"Yep, that was the first thing I checked.  This has really baffling."

I  meant to say, "Yep, it was the first thing I checked and my speakers were OK.  This is really baffling."  Sorry about that.  

My NAD and the ZTOL40 are sitting on the floor in between and parallel to the speakers, and not on the rack.  The ZTOL40 is an LTA demo amp and it is well broken in.  For A/B comparisons, I swapped cables and interconnects.  I'm using Blue Jean speaker cables with locking banana plugs and Transparent Super RCA interconnects.

I spent most of my time listening to my regular playlists.  Everything works fine with the ZTOL, not so much anymore with the NAD.  This evening, I'll start experimenting again with speaker positions.

I plan to keep the rack, but move it to the back of my left side wall.  But, first I have to do a little remodeling.  Funny thing, I had several contractors scheduled to give me estimates when this crazy virus mess started.  I've since put that project on hold.   

jimcrane
165 posts
 
Hi Millercarbon,

The quotation is attributable to the British economist, John Maynard Keynes:  "When the facts change, I change my mind. What do you do, sir?”  Not to get philosophical on an audio site, but I think the quotation is the epitome of Enlightenment thinking.

Jim Crane


oldschool1948's avatar
oldschool1948 OP
502 posts
 
Guys, I appreciate the help.  I'm a techie by trade and I recognize that when troubleshooting, you only change one thing at a time. 

Silly me, I didn't expect that adding a rack would cause this kind of issue when two amps play fine in the same position where the NAD has this massive, unfocused soundstage.  

This is bugging me so I'm going to tinker with speaker position this evening.  I'll probably by the ZTOL40 and the massive, unfocused soundstage problem will go away on its own.  But the techie in me won't rest until I fix or vastly improve on the NAD soundstage problem. 
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