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How Loud at 8 Hertz ?
While the INFRASUB-18 will reproduce 8 Hz, it is not audible nor does it have enough acoustical power for
you to feel it. The measurements are taken at close range with sensitive instruments. To achieve a flat re-
sponse, full amplifier power is used at the lowest frequencies and very little (<1 watt) in the upper frequen-
cy range. The INFRA dual integrator provides the correct signal strength and therefore amplifier power at
each frequency. As the frequency is lowered the power and excursion required to maintain a flat acoustical
response at high SPL become enormous and not practically attainable for a single driver system. Fortunately
the improved phase response, one of the main benefits of an extended subsonic acoustical response, is pre-
served because the music content is typically not demanding high power subsonic reproduction.
The ideal listening scenario is to have a full bandwidth 8 Hz playback system and play a good recording
without low frequency noise present on it. The playback system can then benefit from the improved phase
response without requiring excessive power in the lowest octave or engaging the Dynamic Filter circuit.
Setting the Bass Level
If your application is in a recording studio, you should use professional acoustical measurement instrumen-
tation to set the bass level correctly. For home applications you can set the INFRA level as desired for your
personal taste. You will probably find large variations in the amount of bass energy on various recordings.
Until recently there has not been enough attention to low bass monitoring in the recording studio, post
production and mastering process to insure a low noise, uniform low bass response on the recording. With
an INFRA subwoofer system, you are able to hear the bass with definition and clarity never before available,
making it easier to identify not only the basic level discrepancies, but also the subtleties of the recording
environment ambiance and the bass instrument character.
Amplifier Overload Protection
The duty cycle of even the most demanding bass heavy musical material played at full level is below the
high temperature protection shut off setting. Occasionally, when playing a poorly mastered CD with high
level sub-sonic noise on it, or when running very dense material highly concealed, the system will self pro-
tect and shut off for a short time. If this occurs, turn the level down and/or examine the source material.
