Octet Matrix Audio DE5B-DW50 User Manual - page 12
Page 12
Copyright© 2011 Octet Matrix Audio
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 ear protection (over the ear or earplugs) and slowly turn up 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. 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. 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 volume until you hear the
clearly defined point of high distortion. Back off of the Main System Volume control until the
high 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
distorted before the level determined in the previous step, turn down the Main System
Volume to a level that is comfortable and is the loudest that you would ever use. This is the
Maximum System Level used to optimize the wireless system dynamic range.
Maximum System Level Using Source Material
This technique is the same as the confirmation phase from the prior method. Choose some
source material similar to what you normally listen to. Try to select material from different
genres as the dynamic range, and therefore the apparent loudness, varies significantly across
genres. Play the chosen source material and turn the Main System Volume up to the point
that is as loud as you would ever listen for each selection, or to the point that distortion
becomes objectionable (Distortion may be the limiting factor in many systems). Turning the