UAD Helios 69           Back to fader8's audio blog Index

UAD Helios 69 Study. Version 5.1 AU

Measurements at 96kHz, 24 bit, 0.7Hz resolution, Blackman-Harris windowing.

1. Null Performance

The Level Adjust has a +10 to -20dB range. The EqCut switch disables the EQ bands, but leaves the

plug-in active and imposing its null characteristics. The Line switch bypasses all processing.

Magnitude, phase response and harmonics with null settings:

2. High Shelf

These are hard settings, not continuously variable.

This is actually a combination of +high shelf and a high cut control.

3. Mid Peak & Trough

This gain parameter is continuosly variable. 2.8kHz shown.

These mid peak center frequencies are hard settings.

3. Bass Peak

This control requires a bit of explanation. Rotating counter-clockwise, it provides a bass peak of

+4dB immediately, at the selected frequency. This is shown in the left-hand plot. Increasing the gain parameter

actually adds the dialed in gain to the 4dB. This is a "boost only" control. The right-hand plot shows gain settings 

of 0, 3, 6, 10 and 15dB at the 200Hz setting.

(Note that at 60Hz, it's really a shelf band.)

4. Low Cut

Rotating the control clockwise provides a fixed low cut at 50Hz. The gain control

has no effect on this parameter.

Note that the Peak/Trough switch, (PK/TR) attenuates the whole signal by 1dB when set to 

the TR-trough position.  This is reflected in the above plots where I left it in TR. Oops.

5. Harmonic Distortion

Mid-peak set to +6dB @700Hz. 

700Hz test frequency:

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