Ideal for enhancing punch and tone in stereo mixes, the API Audio 2500+ is a stereo bus compressor with a number of unique features that give it an edge in shaping dynamics. With selectable feedforward (new) and feedback (old) modes and selectable preset or variable release time control, you can precisely sculpt your dynamics to handle any program material.
The front-panel control features are extensive and include: a 3-way THRUST circuit control for enhancing low-frequency punch, selectable soft, medium, and hard-knee compression modes, selectable auto or manual makeup gain control, and separate compressor-in and hardwired bypass buttons. The innovative Mix/Blend section allows you to select between standard compression only output, cross mode for internal cross processing (wet-/dry-style blending), and parallel, which lets you mix your compressed signal into a static uncompressed signal. The 2500+ sports a useful Link section in which you can engage in stepped link control ranging from independent to 100% link in six steps. You can switch the detection speed of the Link section, switching the speed between fast (peak) and slow (RMS). Finally, stereo illuminated VU meters are included with selectable source monitoring, allowing you to select between monitoring input, output, or gain reduction levels.
- Threshold control (continuously variable) ranging from +20 to -20 dBu
- An over-threshold LED indicator is included above the threshold control
- Seven fixed attack times: 0.03, 0.1, 0.3, 1, 3, 10, and 30 ms
- Seven fixed compression ratios: 1.5:1, 2:1, 3:1, 4:1, 6:1, 10:1, and Infinity:1
- Six optionally fixed release times: 0.05, 0.1, 0.2, 0.5, 1, and 2 seconds
- Continuously variable release times ranging from 50 ms to 3 seconds
By switching the THRUST button in either the medium or loud positions, this inverse filter evens out the energy by lowering the energy in the low frequencies and increasing the energy in the high frequencies, so each octave has the same energy instead of each octave having half the energy as the one lower. This creates a unique compression effect that reduces the overall gain, but the sound is much punchier and the signal actually sounds much less compressed.
While engaged, the link control has selectable detection speeds—fast (peak) and slow (RMS). The 2500+ has two completely identical compressor circuits—from the input, through the RMS detector, to the VCAs, and to the output section. When the 2500+ is linked, the control voltages are summed together, but both channels still detect their own control voltages. This eliminates changing the tone of the compressor when linking is used.
- Off: this offers the compressed signal only
- X (Cross): this setting allows the Mix control to be adjusted between 100% uncompressed to 100% compressed, increasing one while decreasing the other
- II (Parallel): with this setting, you can use the Mix control to dial in the compressed signal and blend it into the uncompressed signal (which remains the same)