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Audio files

Click on the links below for test tones in 256 kbps MP3 format. To download on a PC, right click + "Save Link As". To download on a Mac, ctrl + click. If you need to make these longer, you can edit them using Audacity or other audio editing software.

50 Hz and 1 kHz tones mentioned in the website article "Show and Tell: The Schroeder Frequency."

Test tone described in February/March 2011 Sound+Vision article "Subwoofers: 4, 2, or 1?" Consists of sine waves in 1/6-octave steps from 20 to 80 Hz at -15 dBFS peak. NOTE: As with any material containing intense low-frequency signals, exercise caution with your subwoofer level setting when you play this tone. Playing it too loudly can overload the amp or damage the driver. If you hear distortion, reduce the level.

Six 6.5-cycle test tones for CEA-2010 measurements, spaced by 1/3rd octave. These are great for testing subwoofer distortion and output. You can watch the results on a real-time analyzer, or just listen, because distortion is easy to hear with these:

63 Hz     50 Hz     40 Hz     31.5 Hz     25 Hz    20 Hz

Pink noise at -18 dBFS. Play this and view the result on a real-time analyzer (RTA) to see how flat the response of your system or subwoofer is in your room.

Sub crossover test tone in 1/6th-octave steps from 40 to 140 Hz at -18 dBFS (40-45-50-56-63-71-80-89-100-112-125-140 Hz). Play these and measure the level from your listening position using an SPL meter to test the settings on your subwoofer crossover. Adjust the crossover frequency and subwoofer phase control so that the levels of all tones are as consistent as possible. (It won't be perfect because of the acoustics of your room.)

Resources

TrueRTA: Great spectrum analyzer software for DIY audio measurement
RightMark: Awesome free audio measurement software
Room EQ Wizard: Still more awesome free audio measurement software
Harman Research: Loads of great audio papers
Don Keele's website: Still more great audio papers