© Hybrid Audio Technologies, 2010
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follows (this example assumes a right-hand driven vehicle---PLD’s are always a positive
number):
X – Y = Z
Where:
X = distance of the center of the left speaker from your left ear.
Y = distance of the center of the right speaker from your right ear.
Z = pathlength difference.
Applying this formula, assume that the distance of the left speaker from your left ear is
140cm, and the distance of the right speaker from your right ear is 100cm, the pathlength
difference is 40cm.
Good stereo imaging is completely dependent on arrival times of the fundamental vocal
frequencies. Differences as little as 10 microseconds can be detected by the brain. A PLD of
30 centimeters equates to the sound from the nearest channel arriving about 0.9 milliseconds
earlier than the furthest channel. It is Hybrid Audio’s opinion that the end-user should try to
keep PLD’s to less than 30 centimeters in a vehicle which is intended to have good imaging
and staging character
from both seated positions
.
The best way to go about evaluating certain locations in your vehicle is, in general, to look for
the potential locations as far forward and away from you as possible, but still with a general
“line of sight” to the speakers (particularly the speaker on the far side of the vehicle). An easy
way to test various potential locations is to hold a tape measure or other measurement device
from the potential speaker mounting locations, and measure those locations with respect to
your ears.
Reference Figure 2, below. In this scenario, three potential locations for the mounting of the
I69 midbass driver are shown:
Figure 1: Potential Locations for Mounting the Imagine Midbass Speakers
