Maag Audio EQ4M Mastering Equalizer #40558 (Used)

The Maag Audio EQ4M Mastering Equalizer 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 10 Hz and 75 kHz — 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 2.5 kHz 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 +15 dB 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 -10 dB range and both a green signal present led (-20 dBu) and a red peak LED that flashes with +23 dBu peaks.