For recording and live performance a common practice is to place a microphone very close to a guitar speaker cabinet and connect the
output of the microphone to a recording device or a mixer. This approach has several problems. First, it requires using
large and heavy speaker cabs. Also, the results can be somewhat unpredictable due to technique and bleed-through from other
A speaker emulator DI load box can be used instead of a speaker cab and microphone to take the speaker-level signal
directly from an amplifier and output a signal than closely mimics the sound of the closed-miced cab.
I purchased several speaker
emulators and found that they all had some limitations. All of them either didn't sound like a speaker cab or had too little
control over the sound. Also, the ones with an internal dummy speaker load required the purchase of a different unit for each
impedance (4, 8 or 16 ohms).
I designed a filter circuit that matches the frequency response of a typical 12" guitar speaker.
I also designed a dummy load that matches the impedance vs. frequency characteristics of a typical guitar speaker.
I added two controls to provide control of the tone.
I think the result is a speaker emulator load box that can replace
a speaker cab and microphone without sacrificing tone. I hope you agree.
Surprise Sound Lab