Real Time Analyzer - Windows - Recommendations

I've been meaning to post results after measuring my Summits (and room) with the XTZ Room Analyzer (version 1). I'm about to tear down my setup, as we're installing wood floors in the family/listening room, and doing a kitchen makeover. So I did one last XTZ measurement as a reference for comparison after the remodel. All measurements were done with the test signal into my C-J preamp, with mic at ear level in the "sweet spot." This time around, I did NOT measure from multiple locations.

Full range frequency response. Not sure if the rolloff at higher frequencies are due to rear wave cancellations, or perhaps aging preamp tubes or stat panels. Next time I'll try feeding signal directly to amp, to eliminate the preamp variable.



Bass RTA measurement. XTZ calculated "no room nodes," but not as smooth a response as I'd like. No doubt the "new" room will measure differently...



Full Range RTA measurement with RT60 reverb and 2D waterfall plot (sorry, forgot to save the 3D plot)...



My understanding is that RT60 should ideally be < 0.5s.

If anybody else is using the XTZ Analyzer, I'd love to compare results. Also, being an "RTA interpretation neophyte" I welcome comments and explanations about my results!

Hi Alan,

I hope all is well!

Can you re-run 10-250Hz @ 12PPO? I think the latest XTZ SW supports this and it's a more useful resolution for the modal region.

Also a full-frequency FR plot, 20-20kHz? 3 or 6PPO are best for this. Do this for left only and/or right only, not L+R.

I tried to find your system thread, but could not easily do so. Remind me of what you're using for mains, and if you use sub(s)/Xovers?

I can't post XTZ graphs since mine is invariably loaned out to MLC members or others as an inducement to get them interested in measurements. I can post similar Omnimic data, if you're interested.

As I've posted a couple of times, Nyal Mellor and Jeff Hedbeck published a nice paper describing desirable conditions for 2ch reproduction. It's easy to understand and may be found here: http://blog.acousticfrontiers.com/storage/acoustic_measurement_standards.pdf

Ken

Ken,

I actually just loaned my XTZ Analyzer out to an audiophile friend for a couple months, as I'm dismantling my system. It'll be ~3 months before I'm up and running again. We d/l the latest XTZ Pro software to his laptop, and were suprised to find that it works with the original XTZ Analyzer kit. However, I wonder if the mic calibration is still accurate.

I've read some of Nyal's posts on his website and other forums, and will continue educating myself during this downtime.

I'll remeasure my system once the remodeling is complete. FYI, my system is #55... http://www.martinloganowners.com/forum/showthread.php?6203-System-55-(Summit)

Unlike REW and Omnimic, XTZ has no .cal file to load, so presumably the mic, itself, is calibrated to some acceptable tolerance. I can verify this with Nyal, if you like.

Are you using the NHT sub for 2ch or only for movies/multi-ch music?

I was using the NHT only for 5.1 home theater. I'm contemplating getting one (? two) of the forthcoming ML Balanced Force subs, but based on my XTZ measured bass performance, don't know if it will add much for two-channel playback. I'll re-measure with 12 PPO once I'm set up again.

FYI, whenever I run an XTZ measurement, I usually save a .bmp (File- Export Screen Dump) for future reference (and ability to share via email or forum uploads). Hopefully others using XTZ will likewise do so and upload their graphs!

sleepysurf said:

I was using the NHT only for 5.1 home theater. I'm contemplating getting one (? two) of the forthcoming ML Balanced Force subs, but based on my XTZ measured bass performance, don't know if it will add much for two-channel playback.

Click to expand...

Alan, measurements @ ~60dB won't tell you much about the sub's capability. What you want are max output measurements within acceptable distortion limits. I've no idea what those would be for the NHT as it's not listed @ the trustworthy review sites I know of, like Databass or Ricci's old list. If you can find those measurements, you'll have a better answer re: capability. OTOH, if you like how the NHT performs now, why worry?

FWIW, and it probably ain't much, I was running a JL f112 + Velo DD12 in my 2ch only, 13x20 room. Easy to get flat FR to 15Hz at reasonable measurement volumes. But, being a compulsive++ personality, I swapped the Velo for a SubMersive. Bass quality is hugely better, esp. when I hit 100dB musical peaks, and when I say "better", it's not about volume or VLF, but effortless clarity on things like tympani, etc.

I'll definitely re-measure at 12 PPO, and aim for ~90+ dB next time! The NHT Sub Two is a vintage model circa late '90's, and only goes down to 21 Hz. However it was highly regarded in its day, with its sophisticated outboard controller and dual profiles for either music or home theater. Full specs here... http://www.nhthifi.com/s.nl/sc.16/category.3713/.f

Yup, I read up on the NHT Sub Two yesterday before I posted and it should have plenty of output.

When you do re-measure, please stipulate whether you're using the sub (5.1 ch) or not (2ch, Summits only). For the former, we want to look not only at the modal behavior, but at the crossover region to see if you're getting a linear splice between mains/sub.