Η μονάδα 4000 B Dynamics (B-DYN) 500 series παίρνει τον επεξεργαστή δυναμικής που βρίσκεται στη λωρίδα καναλιών της κονσόλας SL 4000 B και τον τοποθετεί σε μορφή 500 Series. Κυκλοφόρησε το 1976, η 4000 B ήταν η πρώτη κονσόλα που κατασκευάστηκε ποτέ από τη Solid State Logic και χρησιμοποιήθηκε περίφημα στο «The Stone Room» στα Virgin's Townhouse Studio (Λονδίνο), Le Studio (Μόντρεαλ) και Record Plant (LA). Ήταν υπεύθυνος για αμέτρητους εμβληματικούς δίσκους, συμπεριλαμβανομένου του «In the Air Tonight» του Phil Collins και του «Intruder» του Peter Gabriel, και τα δύο διαθέτουν χαρακτηριστική συμπίεση σε ντραμς και φωνητικά. Η μονάδα B-DYN επιτρέπει στους χρήστες να προσθέτουν πολύχρωμη, εντυπωσιακή, κορεσμένη συμπίεση από μία από τις πιο σπάνιες κονσόλες στούντιο που κατασκευάστηκαν ποτέ στην εργαλειοθήκη παραγωγής τους.

Compressor/Limiter

RATIO - Stepped compression ratios 2:1, 4:1, 10:1 and ‘ds’. The ‘ds’ setting is a fixed 10:1 with an additional sidechain filter. When ‘out, the compressor is bypassed    

THRESH - Whenever a signal exceeds the level set by this control, the compressor will start to act at the ratio set by the RATIO control. The THRESH’old control also provides automatic make-up gain. A small improvement to the linearity of this control has been made in the module over the original channel strip control. This helps with Threshold tuning using the smaller scale 500 series knobs.    

HPF - A 6dB/Oct 185 Hz High Pass Filter in the compressor sidechain to help reduce bass pumping effects  

RELEASE - Switched/fixed release ranges from .2 ms to 1.6 ms with additional ‘DS’ & AUTO release options.   

DS - The De-Ess mode changes the attack time from approx. 30 ms to 2 ms. 

De-Ess (DS) mode

By setting COMPRESSOR RATIO and RELEASE controls to ‘DS’ the B-DYN module is optimised for reducing sibilance (De-Essing). The De-Ess ratio is a 10:1 ratio with filtered S/C input signal, delivering broadband compression triggered by sibilance typically in vocal sources. The ‘DS’ release is automatically varied in response to the processed signal between release rates of 30 & 50 ms. This is a much faster minimum release than you would normally expect from an SSL Dynamics section. The Attack time is also reduced to a fast 2 ms, slightly faster than the E-Series Dynamic module on its FAST setting)

Gate/Expander

The B-DYN Gate & Expander section can act as a 20:1 Gate or as a 2:1 Expander when the EXP button is pressed.  

RANGE - Controls the maximum amount of gain reduction applied by the gate/expander. When set to ‘out’, the gate/expander is bypassed.  

THRESH - Sets the threshold above which the the gate/ expander will be opened.   

RELEASE - Sets how long the signal remains audible after the gate/expander closes.  

EXP - Switches the gate to expander mode with a gentle curve, for subtler control of level below the threshold. 

The attack time of the expander/gate is a fast 0.2 ms.