SSL 4000 G Bus Compressor
INTRODUCTION
Making mixes sound bigger, with more power, punch, and drive, the SSL G brings cohesion and strength to your mix without compromising clarity. To this day it remains a key element of the SSL sound and has been featured on countless classic recordings. With simple, intuitive controls and transparent compression characteristics.
HARMONIC ANALYSIS
To analyse the non-linear behaviours of the SSL 4000 G Bus, I ran a 100 Hz sine wave through the plug-in at various settings.
100 Hz sine wave at -12 dB passed through G Bus at Unity
100 Hz sine wave at -12 dB passed through G Bus Output +12 dB
100 Hz sine wave at -12 dB passed through G Bus +15 dB
The G Bus has strong third order harmonics, which are associated with richness and depth.
The second and forth harmonics are boosted slightly when driving the output; DC is also reduced, perhaps due to hitting the output transformer a little harder?
SATURATION CHARACTERISTICS
For this test I ran drum and synth loops through the G Bus at various settings. I have compensated for level so that the loops peak at -1 dBFS for maximum resolution of the waveform in Pro-L.
Dry Drum Loop
Drum Loop passed through G Bus at Unity
Drum Loop passed through G Bus Output +12 dB
Dry Synth Loop
Synth Loop passed through G Bus at Unity
Synth Loop passed through G Bus Output +12 dB
Very smooth and subtle saturation characteristics; driving the output has a slightly more agressive tone.
AUDIO EXAMPLES
SSL G Bus Drums 4dB Compression 300HzSC Mix50%.aif (1.3 MB)
SSL G Bus Drums Dry.aif (1.3 MB)
SSL G Bus Drums 4dB Compression.aif (1.3 MB)
SSL G Bus Drums 4dB Compression 300HzSC.aif (1.3 MB)
SSL G Bus Drums Unity.aif (1.3 MB)
SSL G Bus Drums Output12.aif (1.3 MB)
SSL G Bus Synth Dry.aif (1.3 MB)
SSL G Bus Synth Unity.aif (1.3 MB)
SSL G Bus Synth Output12.aif (1.3 MB)
FREQUENCY AND PHASE RESPONSE
Lets take a look at the G Bus frequency and phase response at various settings
What I am looking for is the frequency and phase response of the plug-in at unity and if driving the output circuit changes this relationship.
Spectrum Colours
Yellow - noise generated by the plug-in analysis software to analyse the plug-in
White - frequency response of the plug-in at that particular setting
Red - phase shift of the plug-in at that particular setting
G Bus at Unity
G Bus Output +15 dB
The G Bus has a very linear frequency and phase response.
At unity, frequencys below 20 Hz are rolled off; when the output is driven, frequencies below 30 Hz are boosted a couple of dB. This does add a little bit of power in the low end.
