REACTIVE LOADBOX WITH IR LOADER AND ATTENUATOR
React:IR – is reactive-resonance load box with attenuator and impulse loader with length up to 190 ms.
Let`s figure it out, what means reactive, resonance and why it`s important…
Valve guitar amplifier has relatively large output impedance due to output transformer. Guitar cabinet represents complex reactive load to amplifier and drastically affects frequency characteristic of output signal. Besides, majority of guitar amplifiers have negative feedback, this means that some part of output signal comes again to input of power amplifier and mixes with main signal.
Thus, when we speak about load box, it`s important to understand principles of device operation and its influence on signal.Guitar speaker manufacturers publish impedance curves of their respective products. Usually, guitar speaker have largest impedance at lower frequencies around 70-90 Hz. In real cabinet peak at low frequencies resides slightly higher, for example, in 4x12 cabinet, peak is located around 100-115 Hz due to cabinet construction. Thus it`s important to reproduce not only speaker characteristics, but characteristics of entire cabinet.
Auxillary input for connecting external sources like players, smartphones etc.
Impulse loader input level
5-segment input indicator, for optimal result adjust input level to be in yellow/orange zone, not exceeding red segment.
Output clipping/input signal presence indicator. When Clip indicator lit green, signal is present at input, when clipping occurs at output of impulse loader, indicator switches to red.
Menu button, press to enter menu.
Back button, press to return to previous menu level.
Control dial. Rotate to navigate or change parameter, press to select or set.
Load mode switch
Fan, do not block air flow for proper ventilation.
MIDI In connector for preset switching from MIDI.
Power supply connector, use 7-12 V DC power supply with any polarity.
Historically, different equipment manufacturers produce different types of load box. Initially simple passive type of load is used, then reactive types were introduced, but term reactive can mean only high frequency component without low frequency component. Thus term reactive-resonance load was introduced which means correction not only of high frequencies, but also low frequencies. Graph below represents influence of different load types on frequency characteristics of signal.
React:IR allows usage of all three regimes: passive, reactive and reactive-resonance. Respective mode can be set using switches in Loadbox section on front panel of device.
In addition, device has attenuator, which allows usage of amplifier at maximum volume at quiet “TV” loudness.
React:IR have a number of FX-effects:
Tone Stack emulation can be used in case of some distortion stompbox into line input, for emulation of frequency response of guitar amplifier clean channel.
Impedance Curve emulation can be used for guitar preamp connection into line input, in this case frequency response modified to emulate connection trough guitar power amp.
ADC and DAC characteristics: