Speaker Polarity and Phasing
You were promised more on polarity. Before equalization you should assure that all speakers are in
phase as a system at the listening position. All speakers need to have the same polarity so they move
the same direction at the same time. If they are not, you will not be able to get a proper tune. There are
a number of methods for doing this. We offer one.
Tweeters (A)
: Mute all speakers except the tweeters and play a high female vocal solist. You should
hear the voice at a single point near upper middle of the windshield. If the speakers are out of phase
the voice will not be localized but will seem to come from everywhere. To test: Using the Phase buttons,
change the phase of the right speaker and listen for the difference. Do this a couple of times as needed.
The position that puts the voice in a small single location on the window is the correct phase.
Tweeters (B)
: Note where the Tweeter center is located. It should be just slightly above and to the left of
the center of the windshield (for left hand drive cars). If it is off to the opposite side of center or too fat
to the left, and if you have measured correctly, then you have a gain difference and you can correct by a
slight level adjustment reduce the right tweeter to bring it left or reduce the left channel to take it
right. No more than 1dB or 2dB. Now the tweeters are set. From here on out you cannot change the
levels or phase of either tweeter.
Mids, Mid-bass (woofers), and Subs
: Now mute the tweeters and un-mute the midranges. The
process is the same for each pair of speakers. The sound should come from a single focused point near
the center of the windshield. For midranges and larger drivers, you want to use a deeper male vocal.
The larger drivers are much easier to tell the differences between in-phase and out of phase. Also, with
the larger speakers you will hear a dramatic reduction of bass if the speakers are out of phase.
NOTE: Once each channel pair is adjusted, they cannot be separated. Any change of phase must be done by the pair.
Phasing the Pairs
:
Again, listening to a single vocalist. Mute all channels again except the tweeters.
Then bring in the midranges. If these pairs are in proper phase the sound should be near center in the
upper part of the windshield. If they are not in phase the sound will be pulled down lower. You can
reverse the phase of BOTH mids now and listen for the difference in the sound location. Choose the
phase position that puts the sound high near the center.
Once you have these phased you can bring in the mid-bass with the same process. Again, the focus
should be high in the dash. If the mid-bass is out of phase with the tweeters and mids then they will
pull the sound down toward the floor.
Woofers or Subs
: There will be bass! You have phased the woofers, so we know there will be bass.
What you need to listen for here is location, and mid-bass. (something with kick drums is ideal). Proper
woofer phasing will work with the mid-bass drivers to give good solid, crisp mid-bass. Out of phase will
result in a soft, low-impact mid-bass. Bass out of phase with the mid-bass will also be more located in
the back of the vehicle while a properly phased bass will blend better into the front soundstage.
36
Содержание HDSP-V Series
Страница 50: ...Apex Aprilia ITALY Since 1974 zapco com...
