The EQ4M is Mäag Audio’s flagship mastering equalizer. It is based on the company’s original 6-band NTI EQ3 and like that original 2U equalizer, the 1U EQ4M also includes Cliff Mäag’s unique and noteworthy Air Band® shelving equalizer first introduced in 1993 with the NTI EQ3.
The EQ4M has garnered significant praise as “the most musical-sounding equalizer ever made” because of its classic design, component quality, and high voltage power supply. Powered by an internal high current +/- 18-volt regulated power supply, the EQ4M has a maximum output level of +28.5 dBu while driving 600-ohm load impedances. The unit measures only -2 db down at the extremes of 10Hz and 75kHz—essentially a flat frequency response in the audio range.
Each channel of the EQ4M has six EQ band sections. They are divided into four fixed frequency bell-shaped equalizer sections, a 2.5kHz shelving equalizer section, and the Air Band equalizer with a choice of 2.5, 5, 10, 15, 20, and 40 kHz frequencies. The five frequency bands in the main section are: Sub or 10 Hz, 40 Hz, 160 Hz, 650 Hz, and the 2.5 kHz shelving EQ.
All EQ sections have a boost/cut range of +15dB and -4.5 dB with center position detent at 0 db. The Air Band section has its own bypass button and there are separate hardwire bypass switches for each channel. Each channel also has an Input Attenuator control with a 0 to -10dB range and both a green signal present LED (-20 dBu) and a red peak LED that flashes with +23 dBu peaks.
Frequency Response: -2 dB points, 10Hz & 75kHz
Nominal Input Impedance (XLR): 48 K Ohms, balanced
Nominal Output Impedance (XLR): 50 Ohms, balanced
Headroom: +29 dBu @ 10 K Ohms, +28.5 dBu @ 600 Ohms