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Copyright© 2011 Octet Matrix Audio
source material. You will use your existing amplifier and speakers to determine the Maximum
System Level. The wireless amplifiers/speakers are not used for this procedure.
Maximum System Level Using 0 dBFS, 1 kHz Signal
The most accurate approach is to play the 0dBFS 1 kHz test signal through the existing system
using hearing protection (over the ear or earplugs) while slowly adjusting the Main System
Volume until you hear distortion. Using this approach poses some risk of damage to your
existing equipment, and depending on the power of your main system, to your hearing.
In order to use this method, you must:
1)
Confirm that your current speaker’s power rating matches or exceeds the power
output rating of your existing amplifier or receiver.
2)
Use hearing protection while performing the test.
3)
Ensure that there are no living creatures (that you care about) in the same room or
without at least 2 walls of separation between them and the sound system. If so, they
must also use hearing protection.
Under no circumstances should the main system volume be turned up for more than a
few seconds beyond the point at which significant distortion is heard. DO NOT USE THIS
TECHNIQUE WITHOUT HEARING PROTECTION. OCTET MATRIX AUDIO IS NOT
RESPONSIBLE FOR EQUIPMENT OR HEARING DAMAGE USING THIS TECHNIQUE. IF IT
HURTS, DON’T DO IT!
Using this technique, you will hear two types of harmonic distortion:
1)
Distortion that occurs in all loudspeakers. Even in loudspeakers with high distortion
levels, the distortion increases reasonably linearly with power. You do not need to be
concerned about damage from loudspeaker distortion for short periods of time.
2)
Distortion from amplifier clipping when pushed beyond its ability to amplify cleanly.
Distortion from clipping behaves differently and will go from no distortion to very
noticeable distortion with a small change in power (Main System Volume). We will use
clipping distortion to determine the Maximum System Level.
With hearing protection in place and the Main System Volume set very low ( ¼ volume or
less), play track 5 of the Octet Matrix Audio Test CD. Turn up the Main System Volume until
you hear the clearly defined point of high distortion. Back off of the Main System Volume
control until the distortion levels fall back to loudspeaker distortion only. Make a note of the
Main System Volume at this point. Turn the Main System Volume down to ¼ volume.
Remove your hearing protection and play several pieces of your favorite music starting with
the Main System Volume set to ¼ volume, increasing the Main System Volume until you
reach the level determined in the previous step. If you reach a point that is too loud, or
