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Korg Zero4 Firewire Mixer (Firmware v1.6)
Reviewer: Gizmo • Date: April '08 • Price: £745/€1145/$1299 Link: Korg


Korg Zero4 review

Korg have been around the music scene for ever, ever since musical instruments had plugs. They’ve had fingers in almost ever electronic musical pie and continue to add product to their range with an alarming regularity. While not directly attacking the DJ scene, the KAOSS pads have found their way into many DJs’ bedrooms, studios and rucksacks around the globe. But with the advent of the Zero4 and Zero8 mixers, Korg are waving the “we make DJ gear too” flag with pride.

When the Zeros were sneaked into NAMM 2007 with (wait for it) zero fanfare, technology hungry DJs simultaneously soiled several pair of boxers, broke open piggy banks and offloaded precious family jewels to try and get a Zero of their very own - all based on reading specs and a few reports from the NAMM floor. But being the level headed geeky hacks we are, we’re not swayed by hype and hoopla - we’re only happy if we’ve taken a screwdriver to a piece of gear. That said, having to prise James Zabiela from a Zero4 at last DJ Mag awards judging event made me realise that perhaps it might just live up to the expectations of the masses.

First Impressions

Carrying on the not quite tradition of writing down my first impressions, here goes:

Knobfest - Is it a DJ mixer or mixing desk? Well I suspect it’s designed to bridge both markets. At first, it’s daunting but once you get used to it, it’s less so but still easy to get lost in the layout.

Logical layout - The fader area is nice and clean and all the assorted knobs, buttons and switches are neatly in line with the associated channel fader.

Mixed quality - Hmmm… I found the Zero4 to be bitty in construction, as if assembled from stuff they had lying around rather than being thought about.

Pretty lights - Lots of them too. Switching on the Zero4 treats you to a multi-coloured bootup sequence.

These first impression may or may not last so let’s break the Zero down.


Korg zero4 review

The Zero4 is a 4 channel mixer with effects on the lines and master with multiple EQ modes, Firewire and MIDI - that’s a lot to shoehorn into the body of a 4 channel mixer. But I think Korg have just about pulled it off. The fader area is clean with only faders and channel assign buttons to contend with, but perhaps the crossfader is a tad to close to the edge of the sharp brushed metal faceplate. There’s room to move everything up a little in the fader area - Korg should have done this.

Korg zero4 review

Above the faders lives the EQ and effects controls. What you get are 2 sets of knobs - one for EQ and the other for effects - that are offset from each other and colour coded in a bid to make operation less confusing. Largely this works but with everything being crammed in so snuggly, operation in a rush leads to inadvertent knob tampering. One change I might have made would be to make the fx type knob black, if only to reinforce the fact that it is for effects alone.

Korg Zero4review

Sat at the top of the Zero4 are the input controls. One big white control selects the channel input. It’s not really a matrix assign as such but you can for example assign the mic and guitar inputs to any channel. Taking up the right hand side are 2 banks of controls, one for the sample and master effects and the other for BPM and master volume controls. Obviously, more on those later.


Korg Zero4 review

As I mentioned previously, the construction is a real mixed bag. I’ve become very used to a solidly constructed case with all the bits and bobs dropped inside and finished off with a faceplate. All neat, tidy and solid as a rock. The Zero 4 however feels like the controls have been stick to the outside of a case and finished off with decorative PS2 like heatsinks, a multi-part brushed steel faceplate and some sort of replaceable plastic sheet at the top. It just doesn’t flow for me. The layout is great, but seems to fight with the aesthetics. This is of course largely a personal opinion and some people will adore the looks of the Zero4 - I’m just not one of them.

Korg Zero4 Review

Because so much has been squeezed into a small area, the knobs have been kept to a mixing desk style minimum size which might not be to everyone’s taste. But being plastic pots, I fear for their longevity, given that EQ and effects parameters are likely to get much from hammer from the target audience. And with people likely to use a big bag for the Zero4 transport wise, I foresee a bag full of broken pots for some DJs.

So overall, I’m not as pleased as I could have been with the build. Importantly however, everything feels like it’ll last but without the benefit of time travel I have no way of knowing for sure. Just take heed if you mercilessly punish your gear on a regular basis.


Korg Zero4 review

One area where the Zero4 is kicking much arse is with plugging things in and routing them to output. Normally, I’d leave this towards the end of the review but seeing as it’s such a key issue, I figure I’d get it out of the way right now.

As previously mentioned (assuming you read instead of skimmed), you get 4 channels, each of which has a multitude of inputs:

Mic (with phantom power)
Guitar (yes you read right)
Firewire Audio
Firewire Audio/MIDI
Firewire MIDI

Korg Zero4 review

As you might expect, channels 1-4 can accept a direct input via separate RCAs for CD/line and phono as well as separate 1/4” stereo jacks for another line input - so that’s 3 direct inputs per channel. But what makes this slightly special and dipping its toe in the matrix input pool is the ability to map the guitar and mic inputs to any - or all - of the 4 channels. So from 1 input, you can have a freaky variety of EQs and effects all applied to one audio source.

Having covered the top top 5 in the above list, let’s have a quick skim over Firewire inputs. Via the 18 in/6 out Firewire interface, you can get input to the Zero4. This audio input is cleverly shared with MIDI so you can have audio only, audio/MIDI shared or just MIDI. Strangely, in MIDI only mode, you still get raw audio coming through, but channelled right into the master bus - post EQ and fader.

So like the mic/guitar input, you should in theory be able to route Firewire audio to all 4 channels with the same amount of effects and EQ trickery. That is if it worked. After upgrading the firmware to v1.6, I could only get Firewire audio to channel 1 only.

Cueing and Monitoring

Korg Zero4 review

The Zero4 is well catered for in this respect with post-fader pre-EQ cueing available on all 4 channels. Sadly, effects cueing isn’t possible on the channels or master - it would have been nice to check out an effect in your cans before inflicting it on your crowd. You can however cue up the loop in your headphones, just to make sure it’s the right length and BPM.

Korg Zero4 review

Channel sound levels are shown at the left of each fader with 10 part really small LEDs - 8 green, 1 amber and 1 red. I guess they have to be this size because of the layout but work as you’d expect. The master monitor is 15 part and split for L-R master out but also shows the cueing level if any cue button is engaged.

I have heard many a grumble about the headphone volume being painfully low. Obviously I’m not banging out ear bleeding volumes in a super club but I did crank up the dBs to neighbour annoying volume and didn’t really have any issues. Admittedly the Zero4 was turned up to full monitor volume and I had a set of full ear cans that insulated the sound properly. I don’t think it’s a problem as long as you’re aware of it.

The Wire of Fire

KOrg Zero4 review

Before I start dive headfirst into the deep end of the geeky deep end of Firewire and MIDI, a little word about the manual. Seeing as the Zero4 is one step short of a computer, I had hoped to get a real epic tome of a manual and opening the box, I got a 1/4” thick book. Yay I thought. Sadly This manual is split into 4 languages, leaving just 30 pages bereft of some much needed detail. So I stumbled through the MIDI maze almost alone.

If it’s a DJ product, you can be sure that the manufacturer will try and link it up to a computer somehow, and the Zero4 is no exception. Built right into the back is 2 port (so you can daisy chain) 24 bit 18 in/8 out Firewire card running at 44.1, 48 and 96kHz. But there is one other mode - 192kHz. It’s not available at a system level and you need to reboot the Zero8, but what you get is an 8 in 8 out device but without EQ, effects and the sampler. All this is great but it doesn’t work on a Mac so I’m not able to comment on how well it performs.

Korg Zero4 review

Plugging it into my Mac made it show up straight away and ready for action. Having experienced troubles with a the d.2 Pro Firewire card with regular Mac audio apps, I just went straight in for the kill - Ableton was fired up and of course, all the channels appeared and were freely recordable.

Korg Zero4 reviewRouting is as follows:

1-8: Channel 1-4 pre everything channel signal
9/10: Master out - post everything
11/12: Bus A (crossfader assigned) - post channel EQ/Fader/Effect, pre crossfader and master effects.
13/14: Bus B - as above
15/16: Post crossfader post master effects pre master out.

And being able to record mono of stereo channels in Ableton means you’ve got some pretty comprehensive recording options available to you. I have no doubt that delving deeper with the Zero Edit app would give you an even crazier level of options but this is simply a review, not a tutorial. I’ll leave the really geeky Firewire/Ableton MIDI talk to the people who truly understand the hell out of the subject.

As a footnote, the Zero4 comes with a special edition of Ableton Lite. This gives you a taste of what Ableton can do but doesn’t even begin to scrape the surface of the Zero4’s abilities as it only offers 2 input channels. If you can afford it, grab the full version without delay.


Korg Zero4 Review

One of the first questions people ask of mixers is what are the faders like. Simply walking up and playing with the Zero4 tells me that the line faders aren’t great but the crossfader is smooth. Clearly in need of more info, I busted out the trusty skratchdriver for a more intimate look at the insides of the Zero4. Being well prepared in such things, no mini Allen screws could foil me in my attempts to find out what was living inside and soon discovered that a decent crossfader was installed.

Korg Zero4 review TKD profader

The TKD Profader is made by the same people as the Pro X Fade. It’s not the same fader, but has a high quality feel to it. There’s no adjustment on the fader but in reality it doesn’t actually need any physical adjustment - it’s nice just as it is. Under the front face of the Zero4 are the curve and reverse controls for the cross and channel faders. One control does all channel faders but it doesn’t end there - this is where things get very interesting indeed.

Korg Zero4 review

Coming with the Zeros is the Zero Edit application. This, amongst other things, allows you to tweak the fader curves on your computer. Zero Edit communicates with the mixer to establish the model and then reads the settings already installed on the mixer. You can define your own curves for the crossfader as well as each line fader. You can also define the curve for one line fader and then apply that to all faders. These settings can be saved, recalled and applied on the fly as long as you have your computer at hand.

It works by allowing you to adjust 2 points - the mid and top cut points. The top cut point is the full volume setting as can be saved permanently to the Zero4. The mid point however can be saved and applied to the the Zero4, but doesn’t survive if you adjust the curve control. The crossfader curve can be applied but neither the top or mid points survive a turn of the control. Still, it’s a pretty cool option to use if you like that sort of thing but out of the box, the curves are really good anyway. If you look at how other 4 channel mixers are served fader wise, you’ll see that the Zero4 is bringing more to the table than ever before. And for completeness, the crossfader curve by default is pin sharp on/off with around 1mm of lag - fine enough for even the fussiest of DJs.

Korg Zero4 Review faders

A note about the line faders - rather than individual faders, the Zero4 comes with 2 sets of 2 faders in one fully removable unit. This of course means 3 things:

• You break a line fader and have a big bill for a whole unit.
• There’s no swapping line faders for 3rd party ones of your choice.
• The door is left wide open for Korg to make rotary units for the knob twiddling fans out there.

They feel smooth enough, but knowing just how fussy dance DJs are, they’ll be hankering for rotaries before long. And there’s a lot of sideways movement as well, making me think that a fix is needed sooner rather than later.

Korg Zero4 review facer caps

The above picture shows 3 fader caps - Vestax, Pro X Fade and Korg. The fader caps are very Pioneeresque, being tall and narrow. DJs are somewhat fussy about their caps so it's worth checking it out before buying - it's all about feel.


Korg Zero4 Review eq

Korg have made a huge deal of EQ on all their mixers, even the relatively lightweight KM series. Whereas the vast majority of mixers have one EQ setting (maybe 2 with isolator and EQ), the Zero4 has 11 different types of EQ, split across 3 types:

EQ: Working just like a normal EQ, the Zero4 offers 4 (although it claims 5) settings - Boost, Hyped, Round-Q and Slamming. I’m not going to attempt to describe what they do or how they sound, but I will chastise Korg for calling EQ bypass a setting. And none of them kill either, but that’s more for information than being an issue.

Isolator: 3 settings here, all of which kill just like a good isolator does. While it offers a wider range than a regular EQ, it does offers a lack of refinement. But DJs do love their killing EQs.

Filter: Using the lo (low pass filter), mid (EQ) and hi (high pass filter) controls, you get 3 different filter settings. Not wildly different though, but purists will no doubt appreciate the options.

Korg Zero4 review

And of course, you get a gain control for each EQ channel which does kill regardless of EQ type. I did note a popping when switching between EQ types, even when the gains were down.

A note about the Zero Edit application - while it does report what the EQ setting is for each channel, there’s no way to change it inside the application. And a little bit of rapid turning of the EQ setting can confuse Zero Edit into thinking that each channel can have different settings - which it can’t.

But even with all the options open in front of you, here lies an issue. Despite all these various EQ settings, there is a widely reported white noise issue. I stop myself from saying problem as in general use, it’s not detectable. I disconnected all devices from the Zero4 and turned up the gains to max and it certainly is there. If you switch between inputs as well, you can hear quite a difference in the noise as well. I believe that it’s one of those things you can hear if you know it’s there rather than hearing it without being told. Korg are apparently working on a fix that may well need a hardware fix. It’s up to you to decide if you think it’s necessary.

In all honesty, I’m not really seeing the point in offering such a wide and varied selection of EQ settings when the differences are relatively small. Spending more time ensuring the sound was spot on would have been a better option. I was left with a feeling that the audio quality was good rather than wow good. I was pleased that it did prove hard to overdrive the Zero4. Even redlighting with max gain and max EQ, the sound was distorted but took some going. If you use the EQ as it should be used, you’ll have no issues.


Korg Zero4 Review

The Zero4 comes with 8 different channel effects, each one of which can be applied on a per channel basis but strictly pre-fader only. Without simply writing down the manual verbatim, you get the very self explanatory low pass filter, high pass filter, phaser, flanger, slicer, pitch shift delay and tape echo. Each of these effects has a separate control for time, modulation or feedback as well as a wet/dry control per channel - hence the knob fest that is the Zero4. This is also supported by the fx switch which allows for on/off or temporary engage mode.

Korg Zero4 review

If that wasn’t cool enough, you also get effects for the master channel as well. These effects thankfully are post fader and can be applied to each channel as well, but the same effect to each channel. These effects are slightly different to the channel ones: low pass filter, high pass filter, jet (sort of like a flanger), decimator (makes it dirty and broken), phaser, flanger, auto pan, reverb delay and tape delay. You also get X and Y parameters as well as an overall wet/dry fader for the master effect.

All these effects work very well indeed. With different combinations of line and master effects, you can do some pretty wacky stuff, but just keep an eye on things getting away from you. The delays in particular can soon get away from you and leave you with a seriously mashed up ear bleeding disaster.

Traktor Scratch Certified

Korg Zero4 Review

Native Instruments came up with a cool idea - have a scan over suitably equipped sound card endowed mixers and after a good testing decide if they can wear the “Traktor Scratch Certified” sticker (or in this case tag). Having a serious sound card inside the Zero4 made it an ideal candidate.

Without retreading old ground by going over the whole Traktor Scratch review again, I had no problems at all getting the Zero4 and TS working happily together. One Firewire cable is all that’s needed rather than a whole interface and a bunch of messy wiring. I plugged in, selected the Zero4 from the drop down audio menu and I was off.

Zero4 review

With the help of Jayo over at Pro DJ Forums, I was able to get the send effects working properly which turned the Zero4/TS partnership from good to bloody brilliant.

Here's what I've been able to achieve with a combination of Zero4 and Traktor Scratch effects. Firstly, you can apply a Zero4 channel effect to the signal coming into Traktor Scratch. Once inside TS, you can now apply an insert effect to the signal. And at the same time, the Zero4 allows you to use a channel for send effects, thus not only can you apply a send effect within TS but also on that sent signal on the Zero4. And if that wasn't enough, you also have the master effects on the Zero4 as well. That's a total of FIVE possible effects being applied to one channel - it really doesn't get any better than this. Obviously on my elderly G4, things got a little crackly while trying to maintain a low latency, but on a higher spec'd machine, you should be able to run everything nice and smooth.

Korg Zero4 review

One little niggle - recording your session in Traktor Scratch isn’t working either. You get an option to record channels A-D but all you get is the raw timecode audio rather than master output. I could spend time messing around with Zero Edit to try different routing but out of the box and Traktor Scratch Certified, you can’t record your sets in TS. I’m not that fussed - you can record via other methods. All this routing and rerouting does however indicate that the Zero4 is a complex bit of kit and not for the feint hearted or Firewirephobes out there. I have no doubt that it can work wonders, especially with the Zero Edit app, but equally you could end up with a real mess if you don’t understand what’s going on.

It took some time to get Traktor Scratch working properly with the Zero4, but now it is, I can say that this is by far the best Traktor Scratch experience I've had.

EDIT: After showing this review to NI, they came back with the following comment:

According to the manual the Zero4 provides the Master Out signal on channels 15/16 of its FireWire interface for recording purposes. Unfortunately we could not manage to connect to this output neither on Mac or on PC - this must be a problem of the Zero4 driver or its firmware.

TS could not access inputs 15/16 anyways, but there is a workaround though to record your TS performance it you sacrifice channel 4 of the mixer:

- connect a short RCA cable from the mixers REC Out to the Line Input of the mixer - make sure to mute the channel to avoid loopbacks
- in TS > Preferences > Recording > Recording Source select "Channel D"

This should allow you to record your mix via TRAKTOR's internal recorder.

Sampling and looping

Korg Zero4 Review

Built into the Zero4 is a sampling and looping engine. This is tightly linked with the BPM section and effects engine. In a nutshell, the BPM engine kicks in and from the measured BPM, the sampler grabs a loop and you get to chop it up via the loop length knob. Grabbing a loop is easy - hit the "LOOP PLAY" button to start and stop the loop. The "KEEP" button will flash meaning it has a sample - hit the button to store it.

There's no way of editing a loop as such but you can use the BPM time button to tweak the length to make it match whatever is playing at the time. Gate play is simply a stutter, which is useful for some fancy remix action on the fly. While a loop is stored, you can't apply effects to the master signal though you can apply effects to the stored loop.

Overall it's a useful addition that works well once you get used to it, but I would have liked to see the loop be more editable and have a pitch adjust as well. Being able to keep a loop and make it match whatever is playing as a bridge would have been cool. In fact, the looping section could have been done better if kept out of the effects section and independent of the BPM as well. Speaking of which...


Korg Zero4 BPM

Key to the success of the effects and the sampling is the BPM section. You can get the Zero4 to detect the BPM from an individual channel or on the master out. The time control has 2 functions - to adjust the measured BPM and to engage the auto-detection. This of course can all be overridden with the tap button - which more often than not, I had to use. And even if it did auto engage and detect properly, the reading jumped around like crazy. 4 to the floor dance music is a solid and dependable BPM and not the jumpy reading you’re treated to on the Zero4.

Message to Korg - BPM detection needs some serious work, especially as the effects and looping depends on it so much.


Korg Zero4 review MIDI

What is a 4 channel mixer without MIDI these days? The Zero4 doesn't goes fairly balls out to give you a world of MIDIability. You basically get 2 types - using the Zero4 to control software via Firewire and also controlling external devices via traditional 5 pin MIDI cables.

The Zero4 has 3 MIDI channels - 1 is for Zero Edit to communicate with the Zero4, 2 is for the Zero4 to talk to your computer and 3 is so that your MIDI boxes of varying kinds can be controlled by the Zero4. I lack any external boxes so I can't vouch for how well it performs in that respect.

Korg Zero4 Review

In terms of Zero4 controls, you get everything in each channel from the pan control to the line fader - a total of 13 controls per channel. Loading up Traktor Studio and assigning controls to knobs proved to be no problem and they seemed to work just fine. I merely tested the function rather than doing any long term reliability checks.

Summing Up

Zero4 Review Korg

The Zero4 is nothing short of a beast, sitting on the fence between mixer and studio desk with a clear leaning towards the DJ. Inside the case and underneath the flashy lights lives a whole world of creativity, and at first look, it's very easy to be phased by what you have in front of you - the Firewire, MIDI, EQ and effects - and looking through the manual leaves you still lacking sufficient insight if you're new to such things. I've certainly picked up some important points while pushing the Zero4 through the reviews machine.

The Zero4 is a strange mixture. On one hand, you have a not especially heavyweight mixer aimed at a market that is likely to take it out a lot. It has some truly wonderful creative options but comes complete with an audible hiss (though I believe this has been removed). The MIDI implementation has been well thought out and with the addition of the Zero Edit software, you can tweak the routing any way you like. But for me, it's the Traktor Scratch abilities - especially with effects - that most get my juices flowing. While the Zero4 is a feature packed box, I'd say that anyone looking to use Traktor Scratch should consider one, simply for the creative options offered by using 2 of the channels for effects. Like anything however, you need to try before you buy. If I were in the market for a 4 channel mixer, this would be the one.


Build Quality - 8/10
Not the best built mixer but with TLC (rather than onroad rough-housing) should last a long time. Watch the channel faders and tall knobs.

Sound Quality - 8/10 (9 without the hiss)
Sounds good to me, but the noise issue could be a problem for some - although apparently it's not on all Zero units.

Features & Implementation - 9.5/10

Features by the bucketload. The Firewire implementation makes Traktor Scratch's effects section a unit shifter on its own.

Value For Money - 9/10

Packed with features at a great price, which both make up for my small concerns over build.

The Bottom Line

Taking into account the vast number of features, quality, price and my own needs, this would be my choice of 4 channel mixer.

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