The processing from the Maxxbass plug-in now in hardware format.
The Waves Maxxbass plug-in, which I reviewed back in SOS February 1998, enabled smaller loudspeakers to produce a greater sense of bass depth without requiring any more amplifier power or stressing the speakers. The processing algorithm relied on the fact that the human ear/brain system makes assumptions about certain sounds depending on their harmonic structure. By reducing low-frequency fundamentals and manipulating higher harmonics, it reduced the demands on the speaker system while fooling the ear into thinking that just as much bass was present. It also allowed you to make bass sounds appear louder and deeper, for sound systems with small subwoofers. A further trick it did was to stretch out the length of bass events, which again increased the apparent bass without requiring a higher peak level.
The hardware Maxxbass units under review here do exactly the same thing as the plug-in, and the two boxes differ only in their connectivity options. The full-width, 1U Maxxbass 101 has balanced stereo I/O connections in XLR, jack and terminal-strip formats with a nominal +4dBu operating level, while the half-width 102 has unbalanced I/O on phono connectors operating at a nominal -10dBV. Both units have an RS232 connector to allow for software updates via a PC, and power comes from an included external 16V AC adaptor.
The front-panel controls are few in number and simple in function. Input sets the input gain, where green LEDs show signal present and red LEDs (101 only) show clipping. The green LEDs don't seem to be affected by the input gain setting, so I assume they're wired before the gain control. A Bypass button takes the effect out of circuit (although the gain control remains in circuit) while Intensity dictates the amount of processing taking place.
Because all speaker systems have different bass handling capabilities, both units also have Frequency controls (adjustable from 25-100Hz) which should normally be set between 75 and 90 percent of the low-frequency cutoff for the speakers. This allows deep bass to be attenuated, and also influences which harmonics are used to recreate the psychoacoustic impression of bass extension. For a typical small consumer hi-fi speaker the Frequency control should be set in the region of 50-60Hz, but a few listening tests will soon confirm what works best. For large subwoofers, a 25-40Hz setting would be more appropriate. As the Intensity is increased, the level of the added harmonics relative to the fundamental increases and the harmonics sustain for longer. Once you've set up the controls, you can lock them using a switch accessible through a small hole in the rear panel of the 102 or the front panel of the 101, and a Lock LED shows when this is active.
The effect of the Maxxbass process is most evident when you're working with smaller speakers, where raising the Intensity control certainly provides a sense of increased deep bass. Though the level of the overall bass does increase to some extent, the fundamental is suppressed so that the speakers are under less stress than they would be if the fundamental level increased in proportion to the added harmonics. Some processing appears to be taking place even at the minimum Intensity setting, and I also discovered that setting the frequency control too high produced a noticeably boxy sound — setting it to around 60 percent of the speaker cutoff frequency seemed to produce a more natural-sounding bass end than setting it to 90 percent, at least in the case of smaller speakers. The frequency knob is a compromise to some extent as higher settings minimise the amount of bass energy hitting the speakers, but at the expense of a less natural bass sound. Excessive processing via the Intensity control also increases the bass-end level significantly, producing a somewhat overblown bass sound on normally balanced material, but then the manufacturers have to provide sufficient range so that the unit can also deal effectively with inherently bass-light material.
I wouldn't recommend Maxxbass be applied to studio monitor systems, because the effect is an auditory illusion and monitors are all about telling the truth, but the process can be useful for treating bass elements within a mix to make them stand out more. For example, a synth bass that comprises a fundamental but little in the way of upper harmonics can eat up a lot of headroom, and here the Maxxbass could be used sparingly, adding harmonics to make the sound more prominent without sacrificing any subjective depth. However, you should be careful using the Maxxbass process if your monitors don't have sufficient bass extension to reveal what the processing is doing at the low end. These Maxxbass units would also be useful for preparing special mixes for computer games, radio commercials and the like, where you need powerful bass effects from small speakers.
Maxxbass 101 £299; Maxxbass 102 £199. Prices include VAT.