Manley Vari-Mu
INTRODUCTION
As Manley Labs’ flagship compressor since 1994, the Variable Mu is a tube and transformer-driven classic that exudes hand-made craftsmanship. A gold standard among mixing and mastering engineers, the Variable Mu adds clarity and cohesion to stereo buses or your entire mix.
For this article, I am only analysing harmonic distortions, saturation behaviours, frequency and phase responses. For an in-depth explanation of this incredible unit and how to get the most from it refer to @Danny’s amazing courses.
HARMONIC ANALYSIS
To analyse the non-linear behaviours of the Vari-Mu, I ran a 100 Hz sine wave through the plug-in at unity and with the dual input at maximum.
100 Hz sine at -12 dB passed through Vari-Mu at Unity
100 Hz sine at -12 dB passed through Vari-Mu with Dual Input at Maximum
The Vari-Mu generates both even and odd ordered harmonics, with a prominent second and third, especially when the input is driven. The second harmonic is smooth sounding and adds body, the third adds richness and depth. Surprisingly, the Vari-Mu generates a lot of higher ordered harmonics and noise, high ordered harmonics are considered aggressive and unmusical, characteristics you would not associate with the Vari-Mu sound. These harmonics are mostly under -100 dB with a -12 input, so not that audible.
SATURATION CHARACTERISTICS
For this test, I ran drum and synth loops through the Vari-Mu at unity and with the Dual Input set to maximum. 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 Vari-Mu at Unity
Drum Loop passed through Vari-Mu with Dual Input at Maximum
Dry Synth Loop
Synth Loop passed through Vari-Mu at Unity
Synth Loop passed through Vari-Mu with Dual Input at Maximum
As you can see, the Vari-Mu has soft and smooth saturation characteristics, very pleasing to the ear.
AUDIO EXAMPLES
Dry Synth Loop
Sie-Q Dry.aif (1.3 MB)
Synth Vari-Mu at Unity
Vari-Mu Synth Unity.aif (1.3 MB)
Synth Vari-Mu Dual Input Maximum
Vari-Mu Synth Dual Input 10.aif (1.3 MB)
FREQUENCY AND PHASE RESPONSE
Lets take a look at Vari-Mus frequency and phase response at Unity and Dual Input at Maximum.
What I am looking for is the frequency and phase response of the plug-in at unity and how particular settings change 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
Vari-Mu at Unity
Vari-Mu with Dual Input at Maximum
Wow! I was not expecting that low frequency roll off when the plug-in is at unity. That is considerable, but it sounds great! It is interesting that driving the input stage gradually brings back that low frequency roll off, and then boosts low frequency content at higher settings.