SPL PQ

This is a unique equalizer – for several reasons. It has two times five fully parametric filter bands, each of which can be switched between constant Q and proportional Q! And there’s sheer unlimited headroom and a very special kind of EQ sound – thanks to 120V technology.

The Filter Bands Stepped Potentiometers

Recall of all settings is easy thanks to the potentiometers with 41 steps.

Cut/Boost & 1/4 Gain

Each filter band can be boosted or cut up to 20 dB.

If only minimal changes are required, the 1/4 Gain switch can be used to reduce the boost or cut range from +/-20 dB to +/-5 dB.

Frequencies

We have designed the frequency distribution to overlap widely between the bands, so that problematic frequencies can also be addressed with two bands.

LF 10 Hz – 330 Hz LMF 33 Hz – 1 kHz MF 128 Hz – 4.1 kHz MHF 310 Hz – 10.2 kHz HF 760 Hz – 24 kHz Bandwidth Q

The bandwidth Q determines the steepness of bell characteristic. A small Q is a wide bandwidth and a high Q a narrow bandwidth.

The labeling of the scale is divided into two parts. The values with white background refer to the proportional Q mode and the values without background refer to the constant Q mode.

On/Off

The orange button is used to switch the individual filter band on and off. 

Constant & Proportional Q

The blue button is used to toggle the Q mode.

In constant Q mode, the amplitude is constant regardless of the selected bandwidth. This is ideal for eliminating interfering frequencies.

In proportional Q mode, the amplitude is proportional to the bandwidth. It decreases with increasing bandwidth and vice versa. At the smallest bandwidth setting, the maximum amplitude value is +/- 20 dB, while the maximum amplitude decreases to +/- 2.8 dB at the largest bandwidth setting. This control behavior simplifies sensitive, creative processing and is musically very useful, since high amplitudes become increasingly unusable with increasing bandwidth.

The Center Section Auto Bypass

For an objective evaluation of the edited music program, it makes sense not to switch between the original signal and the edited signal yourself, but to leave this to an automatic system.

It is also an advantage that, for an optimal evaluation of the processing, one does not have to move from the stereo center and can concentrate fully on the program.

With the help of the Interval control the switching time window can be determined. Turning it clockwise extends the time interval.

Link

The PQ is designed as a completely separate dual-mono, two-channel equalizer and can individually process two mono music programs simultaneously. It is of course also possible to edit a stereo program (left/right). If the Link function is activated, the functions LF, LMF, MF, MHF, HF On/Off and Con. Q/Prop.Q on both sides are switched together by the buttons on one side. This makes it possible to activate or deactivate a filter band or the Q characteristic on both sides of the equalizer with a single button operation.

In Link mode, the right side controls the left side as factory preset. However, this can be adapted to individual working habits. If the channel switch of a channel is pressed until it flashes, this channel controls the other side from that moment on.

Channel On/Off

The orange button switches the entire channel on and off.

Play Video Jonathan Wyner from M-Works Mastering talks about PQ and IRON