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Zoom 9050S

Advanced Instrument Effects Processor By Paul White
Published April 1994

Based on the popular 9030, the Zoom 9050S offers combinations of up to eight simultaneous effects from a repertoire of 55 effect types. Paul White investigates the need for speed.

Aside from its menacing black livery, the Zoom 9050S could easily be mistaken for the 9030 — indeed, the new paint job makes it look even more like a top‑end car radio than ever. The 9050S's philosophy and operating system is much the same as that of its predecessor, though the number of available effect types has been increased to 55 and there are various other enhancements, such as an Auto mode for setting up the single‑ended noise reduction and a sophisticated built‑in guitar tuner. The noise reduction behaves like a noise gate with a medium release time, and the fact that it comes between the overdrive section and the delay/reverb effects means that it doesn't tend to chop the ends off decaying sounds. The auto setup mode is very straightforward; you simply plug in your instrument, press the button, and refrain from playing while the 9030 sets a suitable threshold level.

The input converters are 16‑bit linear types using 64 times oversampling, while the output is also 16‑bit linear. All audio connections are on jacks and the front panel includes a high‑impedance input jack for use with guitar and a stereo headphone jack, which is very welcome for private practice sessions.

Obviously designed with the guitar player very much in mind, the 9050S utilises a sophisticated hybrid (analogue plus digital) overdrive/distortion section and a speaker simulator which can be switched to emulate a broad range of amplifier types. An optional foot controller, the FC50, allows the first 40 patches to be accessed via footswitches and also includes volume and controller pedal inputs for real‑time parameter and level control. However, the 9050S's abundance of quality digital effects make it equally suitable for general‑purpose studio or keyboard use and, unlike so many sophisticated effects units, it also features a wonderfully friendly user interface. It's worth emphasising that some of the overdrive and amp simulator settings can also be made to sound quite wonderful on keyboards, especially if you're into wailing solos.

The memory structure of the 9050S is a little unorthodox, in that the 198 available patches come pre‑loaded with factory patches, all of which may be edited or replaced by the user. The factory patches apparently also exist in ROM but can't be accessed directly, so you can't keep the 198 factory settings and then create an additional 198 of your own. However, because the factory settings are permanently stored in ROM, they can be called up to replace the user patches if necessary.

As far as the front‑panel readout is concerned, the patches are numbered A 01‑99 and B 01‑99, though they all have names as well as numbers. The current patch number may be nudged up or down using the Patch buttons below the patch number window, though for live use, using either the optional FC50 foot pedal unit or direct MIDI access of the patches would be quicker. A patch assignment table function is included so that you can match any 128 of the stored effects patches to the 128 available MIDI program change commands. The 9050S has an insert point, allowing an external effect to be connected. This can be programmed to be either on or off in a specific patch; the software allows send and return levels to be adjusted to match the device in question.


Editing patches is surprisingly simple: the two Edit buttons are used to run backwards or forwards through the nine effects blocks, all of which appear as little illuminated tiles to the right of the main display. Whichever module is currently selected flashes. If a tile lights up red, it is active, and if green, it is bypassed. The Module/Bypass button toggles between On and Off for whatever module is selected or acts as a global bypass when the unit is in Play mode. Moving from Edit to Play and vice versa is simply a matter of pressing the Edit button until either the desired module icon is flashing or none are flashing at all.

The effect type may then be selected by scrolling through the available options using the Effect Type buttons. There are up to four parameters visible in the window at any one time, and these may be directly accessed using the four small rotary controls to the right of the front panel. If the effect has more than four parameters, pressing the Page button will cycle through the available pages, each of which can contain up to four more parameters, again accessed via the same four knobs. This procedure is repeated for each of the effects blocks selected, and the edited effect may then be compared with the pre‑edited version before being stored or abandoned. Note that although nine effects blocks are shown, it is not possible to select all nine at once. For example, if the SFX module is used, then the Eff 1 and Eff 2 blocks are unavailable; the maximum number of blocks that can be used simultaneously is eight, though some permutations restrict the maximum number to fewer than this.

The Effects

Many of the effects on offer fall into the usual modulated delay, reverb and pitch‑shifting categories, but even so there are some unusual interpretations which lend a new slant to an otherwise familiar theme. There are pitch shifts that respond to the envelope of the input signal — which can turn a straight sound into something resembling a goose on acid — while the auto wah functions offer enough variation to create voice box, sample‑and‑hold synth filter, and vocoder impressions, as well as the more routine Hendrix and 'Theme from Shaft' cliches. I found the sample‑and‑hold patches particularly nostalgia‑inducing, but they're not the kind of effect you could use all the time!

The pitch‑shifter includes the ubiquitous intelligent option that creates automatic harmonies to a pre‑defined scale — so long as you play cleanly and monophonically — and more gratuitous special effects, such as 'Bomber' and 'Zitar', the latter sounding like anything but the sitar it purports to emulate.

But the most effective treatments are often the simplest, and the slow bowing attack envelope works very well, as does the rotary cabinet simulator. There's also a chorus algorithm which can be set to change its speed according to the dynamics of the input signal — musically very tasteful when used in moderation.

In addition to the wealth of digital effects offered by the 9050S, its overdrive section is capable of close imitations of many contemporary rock guitar styles, and used in combination with the amp simulator, can create a surprisingly wide range of sounds. The unit excels at creating caricatures of heavy metal sounds, so if you want to sound like Spinal Tap or Eddie Van Hooligan at the touch of a button, this is definitely the box to go for. What I like about these sounds is how they capture that sense of throaty power and volume, even when you're monitoring at a very low level. However, the 9050S also behaves reasonably convincingly when you back off the overdrive, revealing a tonal palette extending from Chris Straits to Dire Rea — or should that be the other way around? Other niceties include a patch which filters any electric guitar sound to create a quite passable imitation of a bugged acoustic.

The factory presets include many of the favourites from the 9030, including the rather pretty 'Vai‑able', which creates a very delicate, clean sound by combining stereo delay with a pitch‑shifted 7th. As is the case with pretty much every budget effects unit I've tried, the pitch shifter doesn't stand up to close scrutiny, but when used as part of a more complex patch such as the one just mentioned, it's generally OK.

As a studio processor, the 9050S is gratifyingly quiet when only the digital effects are being used though, as you might expect, all bets are off when you punch in a saturated, hyper‑overdrive guitar patch. Even so, the noise reduction system helps keep guitar patches clean when you're not actually playing, and that's what really counts. Surprisingly, the specification doesn't include the audio bandwidth, though appraised on a purely subjective basis, there doesn't seem to be any obvious lack of top end when it's called for.


Most multi‑effects units offer combinations of the same repertoire of effects, yet some manage to retain a sense of individuality and character. Zoom's effects units fall into the latter category; their effects are rich and warm without being too gritty or harsh, yet they also sound wonderfully detailed. There's something very homogenous about the sound of the 9050S — the effects seem to merge with the original sound to create something new rather than being stuck on top like the icing on a cake. Some of the unusual twists given to the standard effects help create truly unusual sounds, and with a little care on behalf of the programmer, these can be musically valid rather than merely gimmicky. For example, the pitch bend effect, which sounds like a sick goose when used to excess, can be used sparingly to create a convincing brass ensemble sound or as an alternative to double tracking.

The guitar presets show how versatile the 9050S is at creating all the popular rock guitar cliches, but again, there's enough flexibility to approximate virtually any guitar sound you've ever heard on record. Some of the more classic blues and mildly overdriven sounds don't stand too close a comparison with the original, but in the context of a mix, you'll get away with it more often than not. Most importantly, the overdriven guitar treatments manage to sound big and powerful — not like something that's just come out of a little box!

Of course, there is competition for the 9050S, from the Quadraverb GT, various Yamaha units and the new Boss SE70, but each has its own character and the ultimate choice has to be subjective. On the ease of use front, the four control knobs on the 9050S probably make it the friendliest machine of its type around when it comes to programming, and the optional FC50 is a useful addition for live performance.

The degree of performance control offered by the 9050S, while possibly not as comprehensive as on some competing units, is nevertheless as much as most users would realistically need and it has the advantage of being fairly easy to set up. And finally, if the half‑rack format puts you off, don't worry — a set of rack ears is included, which means you can slot the 9050S into any 1U rack space that you happen to have vacant.

For all its improvements and enhancements, I didn't think the 9050S sounded that different to the 9030, so if you already have a 9030, don't feel duty bound to rush out and upgrade. However, if you don't already own a 9030 and you are looking for a versatile yet easy to use effects unit, the new 9050S is up there with the front runners, especially if you need access to a broad cross‑section of instant rock guitar sounds.

Effect Types


  • Compressor
  • Limiter


  • Distortion
  • Overdrive
  • Crunch
  • Hyper Drive
  • External Effects


  • Zoom Noise Reduction


  • 4‑band Guitar EQ
  • 3‑band EQ
  • Enhancer
  • 2‑band Parametric EQ


  • Guitar Amp Simulator
  • Bass Amp Simulator


  • Pitch Shifter
  • Phase
  • Flanger
  • Chorus
  • Auto Wah
  • Cry
  • Metallic
  • Doubling
  • Comb filter
  • Tremolo
  • Octave
  • Pedal Wah
  • Slow Attack


  • Pitch Shifter 2
  • Phase 2
  • Phase 3
  • Chorus 2
  • Chorus 3
  • Flanger 2
  • Cry 2
  • Tremolo 2
  • Step
  • Auto Pan
  • Delay
  • Echo


  • Harmonised Pitch Shifter
  • Advanced Flanger
  • Bend Chorus
  • Picking Modulator
  • Super Cry
  • Bomber
  • Zitar
  • Delay‑Pitch Shifter/Ducker
  • Reverb/Ducker
  • Rotary Effect


  • Reverb 1
  • Reverb 2
  • Early Reflections 1
  • Early Reflections 2
  • Multi Tap Delay
  • Ping Pong Delay

Effect Routing

There are four possible routing arrangements for the effects on the 9050S; the most appropriate one is chosen automatically depending on which effects have been selected, and the user has no way of changing this.

The first mode is straight series routing, where the effects are connected in the order in which they appear on the front panel and where a stereo output is available only on the Rev module. This is implemented when the SFX module is not used, when the Amp module is set to off or mono and when a mono effect has been selected for Eff 2. All three conditions must be met in order for series routing to apply.

The second option is also a series configuration, but this time the stereo outputs on both the Eff 2 and Rev modules are used in the final output. This routing is implemented when the SFX module is not selected, when the Amp module is set to Off or Mono and when a stereo effect has been selected from Eff 2. Again, all three conditions must be satisfied.

The third routing option splits the signal before feeding the Eff 1 and Eff 2 modules so that these are used in parallel. This takes place when the SFX module is not selected and when the Amp Module is selected and set to stereo.

Finally, there is another series chain which takes precedence when the SFX module is active. This essentially restricts the processing chain to mono, except for the Rev module which comes at the end of the chain.

Performance, MIDI And Control

In common with most current effects units, the 9050S includes features that allow real‑time control over key parameters, either via the two pedals (volume and controller) that may be plugged into the FC50 or directly over MIDI. The last parameter page of each effect allows the user to choose which parameter to control and from what MIDI source. MIDI messages that may be used as control sources are: Control Change Number, Note Number, Velocity, Aftertouch and Bender. When using the FC50, only Control Change number 1 is available.

Individual effect modules may also be switched on and off via MIDI control change numbers. A very practical touch is the inclusion of a MIDI Monitor function that allows the type and range of incoming MIDI control data to be displayed on the 9050S's screen.

Depending on the use to which the 9050S is put, it may be necessary to select a mono or stereo output mode, and this can be achieved via the Utility edit section. Similarly, the output level can be switched between line and instrument level. Patches are renamed from within the Utility section and it's here that the basic MIDI parameters of the machine are set up, including the patch assignment table and a useful Sequence function which enables all 198 patches to be directly accessed from a sequencer using Bank Select commands.

Patches can be dumped, via MIDI, either individually or en masse, and the System content can also be dumped if required. It's also possible to dump just the contents of the edit buffer, including the patch name. To reload MIDI dump data, it is only necessary to select the appropriate screen, which shows the message 'Now Waiting', and then initiate the transfer from the external device.


  • Easy to operate and program.
  • Good range of musically useful effects.
  • Convincing guitar overdrive and amp simulator section.


  • Some of the 'in‑between', mildly distorted guitar sounds don't sound as sweet as they might.
  • The pitch shifter, while not being at all bad for a unit of this price, still sounds a trifle lumpy — or should that be a lumpy trifle?


A good example of how flexibility and performance doesn't necessarily mean a complicated operating system. An ideal unit for a guitarist who wants high‑quality guitar effects as well as general‑purpose studio processing.