I’m in the early stages of incorporating acoustical treatment into my theater. I downloaded the REW software with the intention of using it to identify a relevant baseline to compare post treatment results. I’m running windows 7, am using a Radioshack 30-2055 SPL meter and a BehringerUCA202 as my soundcard. I’ve used both the REW help index and the guide by AustinJerry to assist in calibrating both the soundcard and the meter.
After calibrating the UCA202 soundcard I took a measurement and the results are flat and consistent with the pictures in the manual. However, when I uncheck the C weighted SPL box under preferences and measure the results as a confirmation procedure the delta is much greater than the 0.1db in the manual. My test comes back at 109.8db while the soundcard curve is just over 60db. These were my settings when calibrating the UCA202:
Output volume: .50
Sweep: -12.0
Input: .10
In the windows 7 settings I set the mic volume to 10%/10db per the AustinJerry guide for Windows 7, turned off the monitor switch on my UCA202 and used the UCA202’s volume dial to adjust the input/input ref levels to -12dbfs to match the output. My headroom comes back as 8.5 db when running a measurement. I saved this calibration file.
While I was concerned about the large delta from the confirmation procedure I did move on to calibrating my SPL meter. I’ve calibrated the meter multiple times with headroom to measure 110-122db but when I proceed to checking the levels they come back as too low (-59.4). As such, I adjusted the input volume controls in REW to the maximum of 1.000 but the best that does is get the level to -27db. The manual states it should be somewhere between -12db and -24 with -18 being preferable for non-USB mic’s like the RadioShack 30-2055.
Finally, I made a measurement for 20hz-200hz and it’s clearly not right. Here are some photos of the card calibration and the 20-200hz measurement
Not sure what my next step should be.
After calibrating the UCA202 soundcard I took a measurement and the results are flat and consistent with the pictures in the manual. However, when I uncheck the C weighted SPL box under preferences and measure the results as a confirmation procedure the delta is much greater than the 0.1db in the manual. My test comes back at 109.8db while the soundcard curve is just over 60db. These were my settings when calibrating the UCA202:
Output volume: .50
Sweep: -12.0
Input: .10
In the windows 7 settings I set the mic volume to 10%/10db per the AustinJerry guide for Windows 7, turned off the monitor switch on my UCA202 and used the UCA202’s volume dial to adjust the input/input ref levels to -12dbfs to match the output. My headroom comes back as 8.5 db when running a measurement. I saved this calibration file.
While I was concerned about the large delta from the confirmation procedure I did move on to calibrating my SPL meter. I’ve calibrated the meter multiple times with headroom to measure 110-122db but when I proceed to checking the levels they come back as too low (-59.4). As such, I adjusted the input volume controls in REW to the maximum of 1.000 but the best that does is get the level to -27db. The manual states it should be somewhere between -12db and -24 with -18 being preferable for non-USB mic’s like the RadioShack 30-2055.
Finally, I made a measurement for 20hz-200hz and it’s clearly not right. Here are some photos of the card calibration and the 20-200hz measurement
Not sure what my next step should be.
