Issue 86

Two Classic EQ Emulations Come To Antelope’s Synergy Core 

Blonder Tongue Audio Baton and Filtek Mk3 join Antelope's line-up of EQs for their real-time Synergy Core platform, hailing from the 50s and 70s respectively.


12 June 2020

Taking things back to 1959, Antelope Audio presents an authentic emulation of the Blonder-Tongue Audio Baton. An all-tube graphic equaliser so rare and special that it has an album named after it, it is now immortalised as an authentic-sounding hardware-based software effect by Antelope Audio. Time-appropriate looks aside, the original Audio Baton boasts seven separate amplifiers tuned to distinct frequencies, followed by high- and low-pass filters running in parallel with their outputs routed to separate level controls. 

Choices for frequencies correspond to actual notes and octaves on a piano keyboard. Red markers move up and down the white vertical stripes when turning the associated rotary controls to assist with visualising boosts and cuts over nine frequency bands with a 28dB control range per band. Better still, the resultant frequency response curve is graphically overlaid on top of four horizontal stripes where each frequency region is distinctly coloured. 

Clearly technically proficient for its time, the Audio Baton was actually an inexpensive unit that found its way into audiophile homes and recording studios alike. As such, AUDIO magazine qualified it as “…indispensable to anyone interested in dubbing from old records…” while strongly recommending it “…to anyone who does much recording…” when covering it in February 1959. “Rolloff of either lows or highs due to poor microphones or narrow-range amplifiers or recorders can be corrected easily, and response peaks can be smoothed out as desired,” it also noted. 

Antelope Audio’s team of DSP and electrical engineers recreated the Blonder-Tongue Audio Baton in its entirety, exclusively for the Synergy Core real-time effects processing platform. Providing further visual feedback as a purely cosmetic enhancement entirely in keeping with this unique equalizer’s late-Fifties aesthetic, Antelope Audio added a Magic Eye peak meter to Blonder Tongue Audio Baton. Both the vintage original and contemporary recreation compare favourably to other great equalisers of the time — think Altec 9073A ‘Motown’ graphic equaliser curiosity crossed with pre-eminent Pultec tube-amplified make-up gain stage… Synergy Core has gained another must-have hardware-based software EQ effects emulation.

Fast-forwarding back to a highly-successful Seventies-vintage design, Antelope Audio’s emulation of the FILTEK MK3 is a versatile three-band equaliser with modelled transformer-based input and output sections that works in real-time with zero latency. 

As a versatile equalizer that sounds clear and precise — unusually modern for the time, it handles both broad sweeps and surgically-precise applications with equal ability. Its switch and knob combinations encourage experimentation — extreme settings at broad bandwidths turn the high and low bands into respectable shelving filters, for example. Efficient design, employing the best engineering practices and high-quality parts, produced first-class corrective capabilities and also enhancement-friendly frequency ranges. 

Results worth highlighting include boosting the high end without introducing harshness and a unique signal path allowing for parallel equalisation by mixing the boosted/attenuated signal with unprocessed audio. Antelope Audio’s dev team carefully modelled the three-band design with high- and low-pass filters — perhaps the most recognisable and arguably most flexible of the FILTER MK3’s many incarnations. In this case, each band offers a choice of 12 frequencies with boosts and cuts of up to 16dB. The three-way bandwidth (Q) switches for each band allow for bypassing specific bands when in mid-position. With FILTEK MK3, users can expect something special — clean and transparent, but packing plenty of punch and character when pushed. It is certainly an amazing-sounding addition to the frequency adjustment toolbox!


Antelope Audio:
Australian Distributor:

Leave a Reply

Your email address will not be published. Required fields are marked *

More for you

Issue 86