SPL TDX

A classic SPL, now tailored for 500 Series rigs

The TDx is designed as a bridge between a circuit that has become a studio reference and modern workflows in 500 Series format. The spirit remains the same: a musical and direct approach to envelope processing, ideal when a take lacks snap, when a snare doesn't "cut through" the mix, or conversely when a sustain overwhelms the arrangement. The major contribution of this TDx version is its integration as a 500 module, convenient for building a custom chain, recalling routing easily, and placing transient processing exactly where your rack is already at the heart of the system.

Who is it for, and for what: from quick sound design to surgical mixing

The TDx is aimed at demanding home studios as well as pro studios that want an ultra-fast tool to reshape the dynamic behavior of a source. On drums, it allows reinforcing the attack of a kick to gain clarity without necessarily pushing EQ, or shortening the sustain of a tom to clean up the low mids. On rhythm guitars, it can help solidify the "pick" and stabilize the groove feel. In mixing, it becomes a natural ally to reposition a track in the arrangement, add energy to a loop, or tame aggressive transients before more traditional compression.

Transient control: the SPL approach with DET

Attack and Sustain: two parameters, immediate impact

The working principle of the TDx is deliberately simple: you act directly on the attack (the fastest and most percussive part of the sound) and on the sustain (the hold and tail of the signal). In practice, this allows going from a "soft" take to a more incisive sound, or making a source shorter and cleaner to free space in the mix. This approach is valuable when you want an audible result without multiplying steps: no need to reconfigure a compressor, gate, and transient shaper in series, the TDx targets the essentials with an ergonomics focused on efficiency.

"Differential Envelope Technology (DET)": level-independent processing

The TDx integrates SPL's DET technology (Differential Envelope Technology). The idea is to process a signal's envelope while remaining effective even when the input level varies, by calculating differences between generated envelopes. For the user, this translates into more stable and predictable transient processing, particularly useful on lively sources (drummer's performance, percussion, dynamic tracks) where nuance must remain musical while gaining control.

Technical specifications

Frequency response - start	10 Hz	Category	studio effect
Frequency response - end	100 kHz

Input	Balanced	Frequency Range	10 Hz - 100 kHz
Impedance	20 kOhm	Noise	-93 dBu (A-weighted)
Max. Input Level	+22 dBu	Dynamic Range	116 dB
Output	Balanced	CMRR	> -80 dBu (at 1 kHz, 0 dBu input level, unity gain)
Max. Output Level	+22 dBu	THD	0.03% (at 0 dBu input level, unity gain)