The "Official" xtz Room Analyzer Thread

xtz Room Analyzer is a room acoustics measurement system and parametric EQ optimizer. The kit contains a microphone, a base unit with USB connection, and all the cables required to connect to a USB-enabled PC, and to the user's audio system. The software is downloaded from the website and installed on the users' PC, (Windows XP/Vista/Win7.) The system can also run on a Mac under Fusion or Bootcamp.





The system can measure:

1-position Frequency Response, (16 to 250 Hz)
3-position, averaged and weighted Frequency Response (16 to 250 Hz)
2D and 3D Time Frequency Level Charts
1/3 Octave RTA (20 Hz to 20 kHz)
3D Waterfall Charts
RT-60 Reverbation Time

The system can also be used to set filters on a parametric equalizer. The system will measure and analyze the room modes and recommend filters to offset the modes.

The manual can be found here:
http://www.xtz.se/custom/database/fi...0095834-01.pdf

The most recent version of the software is 2.0, build date June, 2009. Software updates, when they become available, will be posted here:
http://www.xtz.se/uk/support/file-archives

There are some special considerations when using xtz RA with Windows Vista. Please see the following .pdf file for more information:
http://www.xtz.se/public/file.php?RE...10452_1_12.pdf

Here are some sample images of xtz Room Analyzer, single position, Frequency Response in the main window and Time Frequency Level in the small window, upper left:





Here is a sample of the RTA display:



Here is a sample of the 3D waterfall graph:



The following are links to reviews of xtz Room Analyzer by Kal Rubinson in Stereophile Magazine:
http://www.stereophile.com/musicinth...tr/index1.html
http://www.stereophile.com/musicinth...39/index1.html

reserved

PPO is "Parts Per Octave". So yes, 6 ppo is the same as 1/6th octave smoothing.


Bass is non-directional, so the microphone can be placed straight up for measuring bass frequencies with the Room Analyzer. However, for measuring Full Range signals of speakers, (RTA, RT-60, 3D Waterfall), the microphone should be pointed at the speaker. The manual states:


Craig

Excellent questions. Unfortunately, I don't have answers. In fact, I am somewhat mystified by the level setting process myself. I don't know how to set a specific level for the test tone. The manual tells you to set the slider in the middle of the range, then adjust the system volume to get the level meter to the green "G".



OK, but what level is that? Couldn't there be an SPL readout? More importantly, what do the SPL numbers in the Y-axis of the FR graph mean?



It would appear that the SPL being measured is about 55 dB. Yet, when I hold an SPL meter next to the microphone during the chirps, I read about 82 dB. This is with the Master Volume Control at -10 WRT Reference Level at 0. Why are the SPL's in the graph so far off from the actual SPL's?

Also, if I use the slider to increase the level, I get the same issue that jchong described, with the system abruptly aborting the chirp and resetting the level on it's own.

In another section, under the RT-60 measurements, the manual states that you need a 100 dB level to take accurate RT-60 measurements. (Background levels in most rooms is about 40 dB, so 40 + 60 = 100 dB.) With my system at MVC 0, I read 92 dB on my SPL meter. Do I need to turn the system up to +8? And with an SPL of 92, why do the graphs read less than 70 dB on the Y-axis?



Hopefully someone from xtz will shed some light on this. I had e-mailed xtz support when I posted this thread and Jens replied that they would look in and offer help if they could. I hope they will.

Craig

Kal,

First, just to be clear, your acronym "SLM", are you referring to a "Sound Level Meter"? Are you referring to the same thing I'm referring to when I use the acronym, "SPL meter", or "Sound Pressure Level" meter? I've just never seen it called an SLM before.

Assuming we are referring to the same device, then I don't understand your reply. These are "chirps", or sine wave sweeps, not noise signals. What would the SPL meter need to "integrate across time" with a sweep? If I hold my SPL meter right next to the xtz mic during the FR sweep, it reads 82 +/- 1 or 2 dB during the entire sweep, (SPL meter set up for C-weighting/Slow Response.) IOW, it (the SPL meter) is reading the SPL of each frequency, not summing the entire signal of a "noise" signal. OTOH, the resultant xtz FR graph shows an SPL of 55 +/- 3 dB, or about a 24 to 27 dB difference. That is a HUGE difference.

If the SPL of the sweep is read by my SPL meter as 82 +/- 2 dB, why does the xtz graph show each individual frequency of the sweep at 55 +/- 3 dB? To my mind, these SPL's should match within the calibrations of the individual devices. Certainly they can't be mis-calibrated by 24 to 27 dB.

Craig