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Line 6 Mod Pro & Filter Pro

Modelling Effects Processors By Paul White
Published June 2002

Line 6 Mod Pro.Line 6 Mod Pro.Photo: Mark Ewing

Two more visually distinctive rack units from Line 6, designed to model the hallowed sounds of antiquity.

Following on from the Echo Pro (reviewed SOS February 2002) come two more modelling rack processors from Line 6, the Mod Pro and Filter Pro, again based on enhanced versions of their stomp box equivalents. Both feature the same clear user interface, MIDI compatibility (In and Out/Thru) and, in addition to 99 factory presets, each unit can store 99 user programs based on variations of their 16 effect algorithms. The balanced stereo I/O is on both jacks and XLRs and there's a rear-panel jack for an analogue expression pedal. Furthermore, virtually any parameter can be mapped to any MIDI controller and relevant modulation parameters may be sync'ed to MIDI Clock. Programs can be mapped to specific MIDI program changes for live performance.

In true Line 6 tradition, the effect algorithms are largely modelled on classic pedals and other vintage devices. The control interface includes input-level metering, status LEDs around the algorithm select knob and further status LEDs next to the now-familiar Tweak and Tweez knobs to tell you what they are controlling in the selected program. A two-digit read-out displays the current patch number, while a second four-digit display (in the oval window) shows context-dependent information including tempo details and parameter names/values. Three buttons below the display access Hertz, Note and Bpm for setting up tempo-related functions, while pressing Bpm and the Global button together accesses the pedal setup mode. The remaining buttons cover loading and saving programs, bypassing the effects, accessing MIDI/Setup details and entering tap tempo values.

Programming is quite straightforward insomuch as you select an algorithm, then adjust the settings using the two modulation controls plus the Tweak and Tweez Knobs until you hear something you like. Mix determines the wet/dry effect balance and tempo-related effects, which can be given different note values, can be set up using manually entered bpm, tap tempo or incoming MIDI Clock. The optional expression pedal can be used to morph between two different front-panel control settings within a patch, making it easy to control speed and depth at the same time, or to change a filter frequency to create a manual wah-wah effect, for example.

Mod Pro

The Modulation Modeller effects include algorithms modelled after the characteristics of the Fender Deluxe Opto Tremolo, the Vox 'bias' tremolo, numerous phasers and flangers (mimicking pedals by the likes of MXR, Mutron and Ibanez), the Uni-Vibe (made famous by Jimi Hendrix) and, of course, rotary speakers with user-tweakable drive, horn depth and drum depth. The Choruses include emulations of the Boss CE1 and the Roland Dimension D, then there's vibrato, ring modulation and auto-panning. As always, Line 6 acknowledge the owners of any trademarks and emphasise that the use of these names does not imply any connection between the companies or any endorsement by those companies.

Tonally, the Modulation Modeller manages to be authentic sounding in most instances, especially the modulated delay pedal effects, and despite the simplicity of the controls there's a great deal of flexibility. There's also the option of controlling parameters via MIDI or of locking some modulation rates to MIDI Clock, but you can have so much fun treating the unit like a rackmount stomp box that I guess a lot of people will never take it further than that. The Leslie effect, while not entirely authentic, is better than you get in most effect units and the Roland Dimension D emulation (the original unit cost much more than this entire effects box) includes the panel switch options of the original and retains the same tonal subtlety.

Filter Pro

The Filter Pro offers self-triggered and tempo-locked effects for processing guitars or just about any other sound source. It also includes a few guitar synth-style effects that rely on pitch tracking and processing the input signal, in which case you need to play monophonically and very cleanly to avoid the sound of a Dalek yodelling on a roller coaster! You might think that there are few classic filters to model, but in fact most of the patches relate to some original piece of equipment which is lovingly described in the handbook. Perhaps a list of the algorithm names would be useful here, as they're somewhat indicative of what to expect: Synth Strings, Attack Synth, Synth-O-Matic, Tron Up, Tron Down, Q-Filter, Slow Filter, V-Tron, Voice Box, Seeker, Obi-Wah, Throbber, Spin Cycle, Comet Trails, Octisynth and Growler.

Line 6 Filter Pro.Line 6 Filter Pro.Photo: Mark Ewing

The first eight effects aren't tempo sync'ed while the second eight can be sync'ed to MIDI note information. Synth String, Attack Synth and Synth-O-Matic are guitar synth emulations based on vintage Roland and Korg models and have a one-octave tune range up or down, but I found I had to play very carefully to get them to track properly — any hint of fret buzz sent them wild. Being generous, I could say Line 6 have successfully modelled the tracking idiosyncrasies of early guitar synths. There's a fair range of tonal adjustment on hand, with a plausible analogue synth sound at one end of the spectrum and something that sounds like a damaged ring modulator at the other. You're on safer ground with the Tron filter pedal, while Q-Filter is really just a static band-pass filter — if you have a pedal, you can use it to set up a wah-like effect. Other treatments include growly filters, vowel filters, sync'ed stepped filter (with 64 different patterns) for that sample-and-hold effect, an octave synth, something dubiously entitled the Throbber (inspired by the relatively recent Electrix Filter Factory), and a patch seemingly designed to imitate whale song!

The back panels of the Mod Pro and Filter Pro share identical I/O facilities.The back panels of the Mod Pro and Filter Pro share identical I/O facilities.Photo: Mark Ewing

In Use

Both units are more flexible than their simple operating systems initially lead you to believe, and the accompanying handbook is friendly and informative. In fact the only thing that's really missing from the whole range is the ability to name patches properly — I thought we'd left patch-changing by numbers behind along with the 20th century! The modulation effects are, to my ears at any rate, more useful in a conventional musical context than the filter effects, but if you desperately need the sound of a guitar being refretted with an angle grinder while it's still plugged in, or if you want to knock up some whale patches to keep your goldfish happy, the Filter Pro's your man. It can create some musically conventional filter effects, but it really excels at being nasty (with a capital 'N'), so my guess is that the dance fraternity will be the most likely to go for it. Treat the guitar synth patches with caution, though, and never play more than one note at once or your sonic world will come crashing down around your ears.

These are not cheap units in the UK, so the gigging player may prefer to buy the pedal equivalents at around half the price. There's no significant difference in sound quality that I can hear, though the rack units are more flexible, have better user interfaces and can store plenty of user patches. Again, both these boxes do pretty much what they say on the tin, but I have to question whether the rigorous modelling of phaser, flanger and chorus pedals offers any real advantage over buying a more conventional multi-effects unit that will be less accurate, but that can also give you delay and reverb at the same time.

If you really want off-the-wall effects, then the Filter Pro is the clear choice, though I have to admit that the synth-style sounds didn't work for me at all. Most just sounded like something broken! Some of the stepped filters are nice though. There are some truly bizarre effects inside the Filter Pro, so your best bet is to check one out in a music store to see if the Line 6 concept of weirdness fits in with your own. It's one of those products that you'll either hate or you'll simply have to own — in that respect, it's a bit like a Bob Dylan bootleg album! Finally, all the units in the series look absolutely gorgeous, but, for me, the Echo Pro (reviewed in SOS February 2002) is the must-have of the range.