SPL Channel One Mk3

High-quality and extensive processing of audio signals

SPL's Channel One Mk3 offers a comprehensive collection of features to ensure the convenient processing of audio signals. The channel strip now includes a higher internal audio voltage (+/- 18V) for optimal and detailed sound as well as a preamp section with a tube saturation stage, transient designer and a mic A/B comparison option for two microphones.

New generation, new features

The controls for the discrete preamplifier are located on the left-hand side of the device. A preamplification of up to 68dB can be achieved for microphone signals using the gain control. The tube saturation control determines the degree of tube saturation of the device. The output level is automatically adjusted and only increases by 6dB at maximum. In conjunction with a further effects section, this allows subtle to harmonic distortion of the audio signal to be generated. The tube saturation effects produce a warm, round and smooth sound.

SPL's Transient Designer circuit, which has been successful for decades, is also integrated: The sustain control can be used to boost or cut the decay phase of a signal by up to 24dB. The decay time is extended when the sustain control is in the positive range and shortened with a negative value. If you want to change the input phase instead, you can use the Attack control, which can be used to boost or cut the attack phase of a signal by up to 15dB. The transient designer is used, for example, to emphasize the attack of a drum or to attenuate the reverberation of an audio signal. The "On" switch activates the complete Transient Designer section, consisting of attack and sustain controls.

The Mk3 version of the Channel One also offers two microphone inputs on the rear of the device for direct comparison of two microphone signals. No cables need to be reconnected for this. Only the "Input" switch on the far left of the device and the phantom power must be set to the desired source.

Control elements

The Channel One Mk3 has the option of reducing the intensity of S-sounds by changing the position of the S-Reduction control. De-essers from SPL work with filters that only process the frequencies of the sibilants, but not the rest of the spectrum, which means that the character of the voice remains unchanged. As soon as an S-sound is detected, a small yellow LED lights up in the bottom center of the device. The "Low & High" buttons of the S-reduction section can each be used to activate a different mid-frequency for the de-esser. If the "Low" switch is pressed, the low de-essing band is activated with a center frequency of 6.4 kHz and a bandwidth of 4.4 kHz. If the "High" switch is pressed, the high de-essing band is activated with a center frequency of 11.2 kHz and a bandwidth of 4.9 kHz. If both switches are pressed, the low- and high-band de-esser are active.

The compressor section on the right-hand side of the device consists of two controls and a switch. The Compression control is used to set a threshold value between 0dB and -20dB. The make-up gain control, on the other hand, raises the level, which has been reduced by the overall level reduction caused by compression, to the set level. A value from 0dB to 20dB can be set. The entire compressor section must first be switched on using the "On" switch. The attack and release times of the compressor are set automatically by the device and thus adapt perfectly to the input signal.

The EQ and Air Band section of the Channel One Mk3 consists of a total of 5 controls. Two of these are responsible for the semi-parametric bass/midrange filter (LMF). The adjustable frequency range of the filter is between 30Hz and 700Hz and the gain/attenuation is determined via the "-/+" control. In addition to the LMF, the device also has a semi-parametric mid/high frequency filter(MHF) with an adjustable frequency range of 680Hz to 15kHz. The gain or attenuation can also be varied using the "-/+" control. The maximum gain and attenuation values for LMF and HMF are +/- 12dB. Finally, this section contains the knob for the air filter. This is used to process the upper frequency range and consists of a coil-capacitor filter with a bell characteristic. Its center frequency is 19kHz, with a possible attenuation/boost of -/+10dB. To activate the equalizer section, the "On" switch must be flipped.

The output level of the device is controlled using the output control in the bottom right-hand corner. The control can attenuate the signal by up to -20dB or boost it by up to +6dB. This function ensures that subsequent devices are optimally controlled. The set output level is visually displayed on the large VU meter in the middle of the Channel One Mk3 when the VU switch is in the "Out" position. If an overload is detected in the device, the red "OVL" LED lights up. The display picks up on all relevant points of the signal flow.