The Headrush is a multi-effects processor that can work with traditional guitar amps, but it also includes amp and cab modeling for direct recording in the studio or for performing live with flat-response/full-range amp systems. One of its main features is a large touchscreen, which invites doing your own tweaks and programming. This issue’s column will take advantage of that capability.
If you have studio monitors, they’re probably bi-amped, with a crossover that separates the audio into low and high frequencies. These feed low- and high-frequency speakers respectively. Bi-amping optimizes each speaker for its intended frequency range, and it reduces distortion because the low-and high-frequency audio don’t interfere with each other.
We can create bi-amping within the Headrush thanks to the Split option, which sends the signal through a pair of chains with four effects slots, then mixes the chain outputs back together. Bi-amping produces a smoother, more focused style of distortion, allows for cool stereo imaging and broadens your palette of sonic options.
How to Bi-Amp
Insert a Para EQ, with the Default preset, at the beginning of each split. For the high-frequency split, edit the following Para EQ settings: Freq 1 = 1,000 Hz, Type 1 = 6 dB, Type 4 = Shelf. For the low-frequency split, choose Freq 4 = 1,000 Hz, Type 1 = Shelf, Type 4 = 6 dB. Freq 1 and Freq 4 should be identical. 1,000 Hz is a good crossover point, but experiment in the range between 500 and 2,000 Hz to find the optimum frequency.
Fig. 1 shows how the Para EQ makes an effective crossover. The top image shows the high band’s spectral response, the middle image shows the low band’s spectral response, and the lower image shows them summed together, producing a flat response. Fig. 2 is the block diagram for a typical bi-amped patch I like, but it’s just one of many.
Filtering the signal reduces the level going to the amp. If you need to compensate for this, increase the amp gain or distortion drive, or precede the Para EQ with a compressor and increase its gain.
The Mix module can make a huge difference in the final sound. I often pan the low band a little to the left, and the high band a little to the right for a realistic stereo image (or exaggerate the panning for more drama). The split’s level controls can help emphasize one path or the other.
The Graphic EQ makes for a good effect for final tone tweaks. The low control is a shelf below about 200 Hz, the low mid is a peak/notch around 300 Hz, the mid peak/notch is near 700 Hz, the high mid is a peak/notch at approximately 1,700 Hz, and high is a shelf that starts at about 2 kHz.
One trick I use for biamped patches is to duplicate the same cab and give them each a different mic. This yields a consistent, yet different sound. You can optimize the mics for the high and low bands.
Craig Anderton’s latest book, How to Get the Best Sounds Out of Amp Sim Software, is now available from Hal Leonard. Please visit craiganderton.com for more information.