It is well known that compression, in its basic form, tends to remove high frequencies from any material with a wide bandwidth. This is because material usually has less energy at high frequencies than it does at low frequencies and since single band compressors are not frequency conscious, the 'highs' are attenuated together with the 'lows'. Using a slow attack time improves matters to some extent, but signals containing many harmonics (eg: vocals, strings and brass) or dynamic signals with a powerful 'leading edge' (eg: piano, kick and snare drum) tend to lose some clarity which often requires further audio processing. It is a fact that many engineers who would like to use a compressor in a particular application, avoid doing so because they feel that the 'sound loses something'.
The DL251 'Spectral Compressor', incorporates a variable 'Dynamic Spectral Enhancement' (D.S.E.) section which eliminates the problems associated with full band compressors by restoring the high frequency energy lost during the full band compression process. This enhancement circuitry is extremely effective where compression and limiting are employed for broadcast transmission, or across complete mixes in a stereo mixdown situation. 'Dynamic Spectral Enhancement' has many creative applications when recording individual components at the multi-track stage, particularly on such programme as acoustic guitar, piano, brass and vocals.