Spectra Sonics audio components provide consistent and predictable audio amplification performance when peak/transient content is included in audio program material. In other words, audio program peaks will not overload a Spectra Sonics amplifier within the audio band pass, 20hz to 20kHz, irrespective of peak amplitudes of 10dB and beyond. Since the introduction of the Model 101 preamplifier almost fifty years ago, the absence of "peak overload" indication devices has been a noted trademark of all Spectra Sonics audio products.

When taken one step further, an audio amplifier that is free of the constraints of audio peak overload now exhibits numerous advantages.

The Vu meter now takes precedence over a peak indicator, which will vary according to audio program content, (ie: percussion versus vocal program material).

Since the Spectra Sonics amplifier is not compromised due to peak overload constraints, low and high frequency response is more uniform, transparent, and free from artifacts created under such conditions.

Finally, all Spectra Sonics audio products utilize high quality input and output transformers. Waveform integrity dictates that reactive components, such as isolation transformers, operate in a non-reactive mode within the audio band pass. Spectra Sonics has used isolation transformers successfully for over four decades. As a result, Spectra Sonics amplification products do not "color", "fatten", or lack of a better word, alter, audio signal characteristics of the input waveform.

The use of Spectra Sonics amplification components will insure consistent performance and preserve dynamic range, harmonic content, low noise and distortion from input to output.


Analog Compressor/Limiters
Two Design Philosophies/Two Differing Results

For almost four decades, there have been two distinct views on how analog compressor/limiters process audio program "peaks" and volume compression, (rms, average).

       Most, if not all analog compressor/limiters operate as peak sensing, volume compressors. Hence, the gain of the device is determined by the peak to average ratio of the program material that is to be processed. As an example, a peak to average ratio 10 dB above average audio program material results in approximately 10 dB of gain reduction for the device. 

       Since the noise of a given audio system is generally fixed, the 10 dB reduction in device gain results in 10 dB increase in system noise. The higher the peak to average ratio, the larger the gain reduction, which results in an increase in system noise and significant loss of system headroom. The Spectra Sonics 610 and 611 Complimiters design employ independent limiting and compression functions, which may be used separately or combined. The limiter function within the 610/611 eliminates the peak overload associated with short time base transients. As an example, if a 10 dB peak to average ratio is present within the program material, the Spectra Sonics 610 and 611 Complimiters eliminate the 10 dB peak overload component and allows the system gain to be increased 10 dB. The overload recovery occurs by virtue of the sub microsecond attack time exhibited by the 610 and 611. The compressor operates independently of this function is not controlled by peak overload components. In addition, peak overload recovery does not affect compressor output. Results of the instantaneous peak overload recovery are readily apparent:

- Dramatic Increase in System Headroom (Dynamic Range)
- Reduction in Distortion                                                       
- Improvement in the System Signal to Noise Ratio