M-Audio EX66, Руководство пользователя

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EX66 User Guide » 3
Setting up your EX66
Monitors
They’re only speakers, so how hard can it be... right? Depending
on your experience with vertical array speakers, it may not be that
simple. The following section can give you useful information on
how to get the best acoustic response out of your EX66 monitoring
setup.
Warning
- Don’t touch the speaker cones! The woofers
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and
tweeter
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are made from rigid but sensitive materials, so it’s easy
to damage them by poking them with your finger. Once they’re
damaged, they’re nearly impossible to fix and will probably need to be
replaced. The front baffle includes a protection bridge for the tweeter
to reduce the likelihood of accidental damage, but you should still be
careful.
Important - The EX66 contains an internal power supply that can
operate with AC power sources of 100V~50/60Hz, 115V~50/60Hz,
and 240V~50/60Hz, allowing you to use them anywhere in the
world. Before you do anything, please make sure the Voltage Selector
switch
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on the back of the cabinet is set to the correct voltage for
your AC mains supply. (The voltage reading in the 6 o’clock position
is the active one. You can use a flat-head screwdriver to rotate the
switch to the proper position if necessary).
Before plugging in and turning on your EX66 monitors, we
recommend you put some thought into speaker placement.
Speaker Placement
Directivity and Room Response
The subject of speaker placement is surprisingly vast as there has
been (and continues to be) quite a bit of research and debate on
the subject. Rather than embarking on a detailed discussion of
electroacoustic transfer functions, reverb time psychoacoustics, on-
axis and off-axis radiation patterns, diffusion and room reflections,
etc., let’s just go through a few basic tips to help you get the best
sound out of your EX66 monitors.
As you may know, a room affects the sound of a speaker by the
reflections it causes. Some frequencies of sound get reinforced
and others get suppressed, the result of which alters the overall
character of the sound. In any listening environment, what you
hear is a mixture of both the direct and reflected sounds. Direct
sound arrives at your ears straight from the speaker diaphragms
while reflected sounds can bounce off of any hard surface to reach
your ears after the direct sound. In general, the direct sound from
the speakers is primarily responsible for the image, while reflected
sounds contribute mostly to the tonality and timbre of the speakers
(richness, leanness, etc.). Any boundary surface (back wall, side
wall, ceiling, etc.) can cause a reflection, so you should think about
reflective surfaces when placing your speakers. To complicate matters,
there are so-called “early” reflections (where sound bounces off of
nearby surfaces, as opposed to far-away ones) which tend to smear
the image because the sound from them reaches your ears very
soon after the direct sound. We usually consider early reflections
to be those occurring within the first 100 milliseconds or so.
As discussed earlier, the vertical array of the EX66’s MTM
configuration greatly minimizes early reflections above and below
the listening position—but you only get this benefit if you position
them correctly in a vertical orientation. So, unlike with traditional
2-way designs, you shouldn’t have to worry about reflections from
the ceiling or mixing console (if your monitors are sitting on top of
a large-format mixing desk).
Important - The EX66 works best in the vertical position. If you
place the speaker horizontally, you will lose many of the benefits of the
MTM design and the sound image will deteriorate.
Figure 3 : Vertical Orientation—GOOD
Figure 4 : Horizontal Orientation—BAD
General considerations
In deciding where to place the EX66 monitors, the goal is to excite
as few standing waves as possible—but the exact way to do this
depends on the specific geometry and setup of your listening
environment. Here are a few rules of thumb to get you started:
(1) The further away you place your EX66 monitors from
horizontal reflecting surfaces (like untreated side walls),
the better.
(2) Try to achieve symmetry within the room; if the left
speaker is 1.5 meters from the back wall and 2 meters
from the side wall, place the right speaker the same way (if
possible) in order to give each speaker a similar acoustic
environment.
(3) We recommend that you place your EX66 monitors a
different distance from the back wall than from the side
walls. In other words, if your EX66s are 0.5 meters from
the back wall, make sure they’re not also 0.5 meters from
the side walls.
(4) As discussed earlier, the EX66 contains a bass-reflex
port
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located on the rear panel. We suggest you leave at
least 150 mm (about 6 inches) of space between the back
wall and the monitor in order to minimize obstructions
to air flow.
Also, remember that the EX66’s narrow vertical cardioid radiation
pattern makes it important for you place them so that the tweeters
are at the same height as your ears.
Figure 5 : Optimal Listening Height