The Issues:
1): Cue/Master level dip: The master and cue when knob is set between the two dip... They are supposed to dip only slightly.. But on the zero 4 they dip too much..
Korgs reply to this is utter crap (big shout to PaulyBatz for contacting them, I hardly get time to call them during the day..) The reason I say this is utter crap is because I MAX out my faders, always have always will. So if the Cue is pre fader and the monitor is post fader and the faders are "maxed", the sound level is the same there should be little to no dip... Just like every other mixer out there...
2): ( I don't really care about this)
No Send and Return Loop: Now that I have had time to reflect, I can and can't understand this one... I can understand it because the board already has effects and a sampler... But I can't understand it because only the Zero8 has the built in kaoss, so what if you want a 4 channel but also use a kaoss.. (they may say buy a Zero8 and I say I don't want a 19" board between my tech 12"s because I use the edge of my anvil crates as a shelf for my bluetooth Imac keyboard.. which can only be done with a 10" or 12" mixer)
3): TSR and Line gain difference: TSR is lower... So you have to crank your gains when in TSR "line" mode... There should be an edit in zero edit or somewhere to adjust this however there isn't.. I think they are expecting you to have a line out level adjustment on what ever you are plugging in to compensate for this, but with some items this just isn't the case.. (work around being to drop your gains for your "cd/line" to about nothing and crank your master, however this bones you when hotswapping between two items...)
4): User Replaceable Channel faders: These should have been single units not paired seeing most guys are going to plug their cd/turntables to channels 2/3 and opposed to 1/2 or 3/4
5): Crossfader Curve Control: The slope to this is wrong according to some.. When setting to blend but blend isn't really not all the way to the left... If you want a true blend with no dip, set it at between 11 and 12 o'clock... Not really an issue just a problem for some, this should be able to be changed and set in zero edit so it is all the way to the left... (ah zero edit I have a big rant about that but I'll get to that later)
6): Heat Issues: I think this was an isolated case for some (yeah I'm one of the isolated few that are having overheating issues), because my studio can get to be a sauna (if I forget to turn on the air), and the mixer is an ice chest compared to my x1500... Meaning it stays cool...
7): Traktor Scratch Certified: What the hell does this mean, I asked some very pointed questions to Traktors Support Dept... and they could tell me nothing more that what was already public knowledge... Which is not very much.. (Traktors documentation and Korgs are about the same... Piss poor)
The question is "AM I going to have to use all four channels to get a time code vinyl to control Traktor or Torq?" So far this is the only way I can do it in Torq (two to send control data, two to receive audio) which eats up most of your board functions that you would want to use for other stuff..
: CD/Vinyl Audio Loops via Zero 4's internal sound card: Why can't I take CD audio or time code... Send it to a pc to add pc effects to, or control a program, and get that processed audio back on the same channel.. When you select I/O in lets say ableton you can select Zero 4 channel input and channel output.. So like I said that audio should be able to be routed directly pre-fader to the pc then pre-fader back...9): Effect parameter mute when changing Time dial: In some effects if you change time on the fly you get some weird sounding stuff... I don't know if there can be anything done about that..
10): Audible Pop when changing effects: If you have effects on and change them mid stroke you will get a audible pop.. This is not detrimental to the channel faders for you do not ever normally do this.. However if you want to effect over a sample that is already playing this becomes a real problem..
11): EQ Selector output change: (edit thanks Seegweed) When changing from EQ to Isolator, to Filter, even with all parameters set at zero (middle), there is an audible change in sound level. (when doing this on the fly.... This brings us back to (zero edit - Eq status... see my comments below)
12): ZERO EDIT: Absolutely pointless...
Fader setting.. Ok you can change the curve (very cool).. But if you happen to bump fader control knob it goes back to normal... (not cool, not cool, not cool) Also why can't you set your own custom slopes for the curve control knobs..
EQ Status... Ok they are all set the the same thing... Via the knob on the front of the unit.. If I need to see that I will bend over and look at the knob on the front of the unit... You should be able to change these and have it set... Like 1/4 to filter, and 2/3 to isolator... Most likely a feature of the zero 8 because I saw a picture somewhere where they were different on each channel...
Audio I/O setting... Ok not enough to change here to get it to do what I think it should do.. (See point
Ok but why is this useless.. Because apparently you are suppose to be able to send changes to the zero 4's memory... I don't see a button to do that... Never seen a prompt saying sending data only receiving data... The only save I see is to save the info in a file to your hard drive.. What if I am not hooked up to my pc every time I dj.. Then I guess any changes I made are null and void when not tethered to my pc..
So can someone from Korg, preferably Jerry, answer my question please?
Hello, This cueing problem with the Zero 4 has been an ongoing thing since it came out. 
... but im thinking of Korg Kaoss! I hope it will be less buggie!