- Advertisement -

Ruby by Acustica Audio Review

Ruby is a replication of a VT-5 vacuum tube equalizer accredited by DW FearnStory. Ruby is an emulation of a high-end EQ which Mr. Fearn the creator of the hardware unit sells for around 9000 USD.

Acustica Audio used their exclusive sampling technology to create a plugin that is close to the hardware equalizer. Acustica Audio did send a review copy with no strings attached.

- Advertisement -


You use the Aquarius tool to install and authorize the plugin after purchase. Updates are distributed through Aquarius software as well. Ruby runs on OSX and Windows as a VST2, AAX, and AU plugin (32 and 64 bits)


Ruby faithfully emulates the sound of a VT-5 vacuum-tube equalizer created by D.W. Fearn. With Ruby EQ you produce smooth instruments or can glue the mix-track. The resulting high frequencies are roomy and breezy. Or do you need liquid, compact and consistent fat low ends?

Ruby has a unique tone and vibe. When you use the preamps on the highs you get creamy results – dial them back when it gets too smooth.The plugin was designed that you can truly boost the HF and it will not sound harsh. Only a handful of developer follow this unique approach.

Acustic Audio Ruby 1

Ruby is fabulous on instruments, the mix bus, and vocals. If you do own Gold (another Acustica Audio plugin) you could combine it with Ruby on vocals for transcendent tone. Ruby is not a good fit for low ends. My guidance is to closely monitor the low-ends results when you use Ruby on an instrument track.

The plugin includes the harmonic deformity performance of the VT-5 vacuum-tube equalizer. It adds phase shift and any frequency response deviations to your taste.

If you are interested in the original unit there is a great video. While the video is about the hardware unit Mr. Fearn comments are usable when you use the plugin version.

When you use Ruby boost the frequencies you need to adjust, there are no recipes (presets) available that fit your mix or track. Use your ears when you set the boosting or cutting in Ruby. It could be used for mastering, but you need to watch the low ends and possibly turn off the preamp in many instances. Overall the character and vibe of Ruby EQ made me curious about the hardware, which at 10k is out of reach.

User interface & Usability

The UI is a replication very closely to the operational mode of the hardware unit. You move from low frequencies on the left to high frequencies on the right. There is a helpful and nicely designed manual available here. Take a look at the video above.

Acustic Audio Ruby 1 1

The CPU drag depends on your hardware and on how many inserts you use. If you do run into issues prints tracks to reduce the load if needed.

You can control through the Interface the EQ and Preamp and gain.


  • Low Cut: at 30, 40, 100, or 400 Hz, 0 to -18 dB shelving
  • Low Boost: 20, 40, 60, or 140 Hz, 0 to 16 dB shelving
  • Mid Cut: 200, 300, 400, 500, 600, or 700 Hz, 0 to -16 dB
  • High Boost: 1.5, 3, 4, 5, 8, 10, 12, or 16 kHz, 0 to 12 dB with Bandwidth Q of 0.6, 0.8, 1.0, 1.4, or 1.7
  • High Cut: 1.5, 3.5, 8, or 28 kHz, 0 to -14 dB shelving


  • Preamp: on and off.

Input and gain

  • Input Trim: from -24 dB to +24 dB
  • Output Gain: from -24 dB to +24 dB

Rating:  Five out of five stars

Ruby glues and presents the mix similar to the hardware. You get a special vibe with a creamy and glued mix. It is a special plugin emulating the vibe of the VT-5 vacuum tube equalizer. Ruby’s ability for smooth High Frequencies and deep, fluid and solid Low Frequencies control as actually emulated tube EQ is unique. Ruby is part of the selected top end tube EQs that are accessible as a plugin.

- Advertisement -