sE Electronics Munro Egg 150 - Manual (Page 7)

Equalisation
The Egg 150 is naturally neutral in its frequency response. This is mainly a result of the acoustically optimal enclosure
and the choice of small drivers with almost perfectly controlled directivity. However, not all rooms are neutral and
also the positioning of the speakers will affect the response. Placing a speaker very near a wall will increase bass and a
corner will have even more effect. This is because energy is reflected from any surface and that energy will be in phase
with the direct sound at low frequencies. This might sound like a good thing but without some degree of acoustic
treatment the results can be unpredictable as at some frequencies the reverse will occur and the reflections will
tend to cancel the direct energy. The Egg has precision trim potentiometers to equalise the bass and high frequency
response for a given location. The HF trim can be used to compensate for acoustic imbalances or (more likely) personal
preference. We all hear high frequencies in slightly different ways and also some allowance may be required for the
intended reproduction of the recording although almost all media have a ‘flat’ response these days. As a general guide
a quarter turn (90 o ) will give 2dB of attenuation of the highest octave (see Fig 3) and that is the preferred setting for
most studio monitoring applications.
Midrange Balance
The Egg 150 has a unique feature and that is the midrange equalisation switch. Most studio engineers are familiar
with the raised mid frequency response of some systems and this can be a useful ‘magnifying glass’ for vocals and
other ‘critical’ aspects of the stereo mix. The Egg offers a subtle (+/- 1.5 dB) hard and soft response modifier. Of course
we recommend the flat (neutral) position for most applications.
Control Unit
The Egg is unique in that all the electronics are housed in a separate unit that can be placed within reach of the
operator and within the listening area. This has several important advantages.
• All balancing and adjustment can be done without having to move back and forth behind the speakers.
• The power amplifiers do not compromise the acoustic integrity of the egg ‘shell’.
• The unit acts as a source select and volume controller in its own right.
• The 3m speaker cables allow the unit to be placed in a rack or free standing.
• Power can be switched without having to clamber behind the speakers.
Protection
The Egg 150 is well protected against electronic malfunction. An LED indicates when the system is approaching audio
or thermal overload and this (when illuminated continuously or for more than a few seconds) should be regarded
as a warning to either reduce monitoring level or allow the system some cooling time. The high currents used in
professional loudspeakers are capable of generating very high voice coil temperatures and prolonged loud listening
can cause driver failure.
Loud transients will pass through the system unhindered and the intermittent triggering of the overload LED is quite
acceptable. Some manufacturers prevent this by limiting and signal processing but this can give a false impression of
true dynamic range and can also impair sound quality.
The HF driver is fitted with a self resetting thermal fuse, if the HF driver stops working reduce the level and allow a few
minutes for the fuse to reset. Then resume working but at a lower level to avoid a repeat.
Setting up your System
The Egg 150 System
Operation Manual 4