Tech Talk
Matching Amplifiers and Loudspeakers for Maximum Output Capability
By Mark Glazer – Sr. Principal Engineer
Introduction:
The performance of a loudspeaker system is largely influenced by the power output capabilities and performance of the associated power amplifier. This article will explain why the combination Mark Levinson No.5802/5805 and the Revel F328Be partner to such a high level of output.
Loudspeaker sensitivity is a loudspeaker measurement of the Sound Pressure Level (SPL) typically at 1 meter, 2.83 Volts input. Sensitivity is used in a loudspeaker specification because a loudspeaker is a voltage driven device. Revel F328Be’s sensitivity is about 91dB SPL which is in the above average range.
Loudspeaker efficiency is important because it describes how much power is required to achieve a certain loudness. It is defined as sound power output/electrical input.
Figure 1, Revel F328Be, On Axis, 1 Meter, 2.83 Volts, Full Space Anechoic
Loudspeaker impedance is the sum of DC resistance and the alternating current, which consists of capacitance and inductance values of the loudspeakers and crossover.
Important to note that because loudspeaker impedance varies substantially with frequency.
Figure 2. Revel F328Be Impedance Curve
Dynamic Testing, F328Be:
Dynamic testing determines the short-term signal handling of a loudspeaker. It is performed using tone bursts at various frequencies. The voltage is increased noting the sound pressure level until the distortion rises rapidly. The SPL below distortion is then documented.
Dynamic tests of the Revel F328Be produce an impressive output of more than 115 dB SPL above 50Hz.
Maximum output of Revel F328Be using ML No.5802/5805
Studies have shown that the maximum spectral output of rock/popular music centers in the 60-80 Hz region, and jazz/classical music leans toward the 100-200 Hz region.
At 60 Hz, the Ml No.5802/5805 produces 205 Watts into 6 ohms.
Using formula , 1.33 W is required to produce 91 dB SPL at 60 Hz for the Revel F328 Be
Using formula, dB= 10log(P1/P2), where P1=205 Watts and P=1.33 Watts, there is a 21 dB gain increase from 91 dB to 112 dB level
At 100 Hz the ML No 5802/5805 produces 300 Watts into 3.2 ohms
Using same formulas for above, , 2.5 W is required to produce 91 dB SPL, at 60 Hz for the Revel F328 Be.
dB= 10log(P1/P2), where P1=300 Watts and P=2.5 Watts, is a 21 dB gain increase from 91 dB to 112 dB level.
Conclusion:
We have now explained how the Mark Levinson no.5802/5805 and the Revel F328Be together produce an undistorted loud 112 dB SPL output.
These two components are priced accordingly to complete a high-end system package.