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In 1998, the SPL Transient Designer created a new breed of dynamic processors. Level-independent processing of attack and sustain of audio signals has revolutionized music production in a significant way.


The newest generation of the Transient Designer 4 features the same processing qualities as its predecessor, but comes in a new design and has an even better feel due to the solid aluminum knobs. The Transient Designer 4 Mk2 offers four Transient Designer channels in one 19″ device.


Transient Designing

SPL Transient Designer – the revolution in dynamics processing.

With the Transient Designer it is possible to manipulate the envelopes of audio signals level-independently (no threshold!). Accelerate or slow down transients, lengthen or shorten sustain times – with just two controls: attack and sustain.

All time constants are automated in a musical way and optimize themselves adaptively according to the characteristics of the input signal.



Attack can be used to increase or attenuate the transient phase of a signal by up to 15 dB. A positive attack value increases the amplitude of the transient response. Negative attack values lead to an attenuation.



Sustain can be used to increase or attenuate the sustain phase of a signal by up to 24 dB. Positive sustain values extend the sustain. Negative Sustain values shorten the sustain.



The On switch activates the respective Transient Designer channel. This allows you to quickly switch between processed and unprocessed signal.

To minimize switching noises, switching is performed directly after the balanced inputs and outputs. This relay hard bypass circuitry also provides immediate redirection of inputs to outputs in the event of a power fault on the primary or secondary side of the power supply, or if the device is powered off.


Signal LED

The Sig LED (Sig) indicates whether an audio signal is
present at the input which has a level higher
than -20 dB.



Channels 1 & 2 as well as 3 & 4 can be linked for processing stereo signals. The respective left channel becomes the master.


The Differential Envelope Technology 

Differential Envelope Technology (DET) enables, through differential envelopes, level-independent processing of dynamic signal characteristics.

Only two controls are needed to control the transient response.

The envelope trackers align the working processes with the natural signal characteristics. This ensures optimum results for every moment.


Inputs and outputs

The four channels of the Transient Designer are equipped with Neutrik XLR sockets with gold-plated contacts. The signal transmission is electronically balanced at a nominal level of +6 dB.


Looks great, feels great - and lasts for a lifetime

The Transient Designer 4 Mk2 has a 4 mm thick, black anodized aluminum front panel. Looks great, feels great - and lasts for a lifetime. The Transient Designer 4 Mk2 has a 4 mm thick, black anodized aluminum front panel and aluminum knobs milled from solid. The housing is made of high-quality steel and is powder-coated in elegantand aluminum knobs milled from solid. The housing is made of high-quality steel and is powder-coated in elegant black.


Sounds good

With all SPL devices we develop not only according to plan, but also by ear. Many important components are installed on the circuit boards using through-hole technology. This way we can ensure that we can use the best sounding components.


The Specs 

Analog inputs & outputs; XLR (balanced)

Maximum input gain

21 dBu

Input impedance

22 kΩ

Maximum output gain

21 dBu

Output impedance

100 Ω

Common mode rejection (1 kHz)

80 dB

Frequency range (-3 dB)

10 Hz – 100 kHz

THD + N (0 dBu, 10 Hz – 22 kHz)

90 dB

Noise (A-weighted)

97 dBu

Dynamic range

118 dB


Internal Linear Power Supply with Toroidal Transformer

Operating voltage for analog audio

+/- 15 V

Operating voltage for relays and LEDs

+ 12 V

Mains Power Supply

Mains voltage (selectable)

230 V AC / 50; 115 V AC / 60 Hz

Fuse for 230 V

T 200 mA

Fuse for 115 V

T 400 mA

Power consumption

max. 15 W

Dimensions & Weight

W x H x D (width x height x depth)

482 x 44 x 237 mm

19 x 1.73 x 9.33 inch

Unit weight

3.2 kg

7.27 lbs

Shipping weight (incl. packaging)

4.45 kg

9.81 lbs

SPL Transient Designer 4 Mk2

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