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Response Down to 8 Hertz
The INFRA is a no compromise technology with a great degree of flexibility. By extending the frequency
response down a full octave below what is considered to be the lowest musical note, low C on a pipe organ
(16 Hz), we improve the phase response and reduce the delay throughout the entire audible bass range. This
excellent phase response and short signal delay is why subjectively the INFRA system is known for its quick,
tight, and musically connected bass sound throughout the entire bass range, not just the lowest frequencies.
With itís good phase and extended frequency response, it can more accurately represent the character of the
sound being fed into the system than conventional designs and their long signal delays.
Dynamic Filter
The Dynamic Filter circuit is a complimentary technology to the INFRA dual integrator. It insures that unex-
pectedly large signals will not overload the system resulting in possible damage or audible distortion. This
allows high level operation close to the maximum system capabilities without fear of accidental overload.
The Dynamic Filter circuit dynamically reduces the bass extension to prevent overload. It is inherent in the
INFRA design that an overload condition will occur with the lowest notes first, as they require the great-
est amount of amplifier power and driver excursion. In an overload condition the Dynamic Filter circuit will
reduce the lowest frequencies to their maximum safe level while not affecting the bass content above the
frequency that exceeded the threshold.
The INFRASUB-18 Dynamic Filter threshold is not user adjustable. It has been factory set to 3 dB below the
amplifier overload point. The maximum sine wave output power from the amplifier is 400 watts. With the
Dynamic Filter detector engaged, the maximum sine wave output power is 200 watts. The full power of
400 watts or more is reserved and available for short duration impact.
The Dynamic Filter is fundamentally different from the commonly used limiter which reduces the level of
the entire sub woofer output, and is much more audible, when engaged. It is more natural not to hear the
lowest frequencies and still hear the upper bass unaffected, as often there are sounds in nature without low
bass content. It is not natural, and very noticeable, when the entire bass range limits to protect itself. When
used in moderation the Dynamic Filter is very subtle and conceals very well the fact that it is working. When
the system is turned up too far, the low bass is reduced to the point that only the upper bass is heard. If
the user requires this much sound pressure, then more amplifiers and speakers are required to achieve the
desired level along with the extended low frequency response.
