Crippled chords without a Full N-Key Rollover

Identifying the problem

What do writers, gamers and trackers have in common? You type so fast that you hold the keys before they appear on screen. The word "the" is so common, you simply press all three keys are pressed at once. But what happens with lenghtier words? BEEP! Or imagine, your rocket launcher refuses to fire because you are doing a diagonal doublejump in a First Person Shooter. It could mean the end of your virtual life.
No full n-key rollover == anger No full n-key rollover == anger
And you probably have noticed chord playing does not always go smoothly with the pc keyboard: when you play some chords, some notes are missing. This specific example was brought up in the forum topic Playing Chords. In summary: certain combinations of keys are blocked. Specific groups of people experience that same problem. But is the software to blame, or the hardware?

Hold e-r-x-c

If you have no idea what I am talking about, imagine being able to press at most one key at a time. That is what it means for a keyboard to have no "rollover". Try entering different combinations of alphanumeric keys in the textbox, like r-y-u and e-r-x-c. All keys have to be pressed at the exact same moment.

Keys accepted:

A good keyboard with a so-called full n-key rollover should allow you to enter all keys simultaneously.

What is causing keys to be blocked?

In the days of old (the digital world is moving fast), each key press was interpreted independently. Regardless of the number of keys pressed, all keys would have been accepted in the correct order. This property is called full n-key rollover. Key rollovers come in various types. Full n-key rollover is the least restrictive type: each key has dedicated electronics. Alpha n-key rollover refers to alphanumeric, which includes all letters and numbers. The "n-key" part means that any number of keys can be pressed simultaneously. Full n-key rollover keyboards are nowadays hard to find. Over the course of years, keyboard manufacturers have sought to simplify the keyboard design. They save $0.07 per key by replacing the individual diodes of each key with a matrix of key switches. The simplified design allows only the most frequently used key combos. Modern keyboard, including those expensive multimedia keyboards, are typically 3-key rollovers. Some manufacturers advertise the shortcoming as a feature, eg. "Phantom Key Surpression".

Where can I get a full n-key rollover keyboard?

Relatively few people need more than a 3-key rollover keyboard, so we can skip all mainstream keyboards. We will have to move on to niche markets. Gaming keyboards cost more than $100. Usually too big and bloated for tracking. On the other hand, manufacturers will think twice selling crap to (semi-)pro gamers. They risk upsetting the complete gaming community.
  • Razer Tarantula10-key "anti-ghosting"
  • Logitech G15/G11 Full n-key (Update: 6-key + modifier)(Update 2: no rollover at all?!)
Office keyboards. Really, I expected more from this category. Aren't professional writers annoyed with 3-key rollovers? And what about braillists, who need at least a 6-key rollover?
  • Fujitsu-Siemens KBPC PX Stopped being full-n key in 2004.
  • IBM Model M (Update: rollover may vary per series) This rarity is the cream of the crops, because/but it clicks very loudly.
  • Cherry G81-8308 Alpha n-key. Expensive, about $140!
  • Das Keyboard A modern reincarnation of the IBM Model M, $129. The Ultimate version has blank keys :D
  • Majestouch Tactile Touch NKRO USB keyboard with 6-key rolloever; full n-key rollover when connected through PS/2
  • Happy Hacking Keyboard Minimalistic 60 key layout. Sexy. Built-in USB hub. And a maximalistic price.
All keyboards listed are supposed to have full n-key rollover. Do not take my word for it and do your own research. Having experienced myself, "should" does not equal "is". When purchasing a keyboard, make sure you can return it. If you can suggest me any interesting keyboards, I will list them here.


  • A PS/2 to USB converter may not be able to handle the required data throughput.
  • The type number does not guarantee that every product bearing it is the same. Specifications change occasionally and may very per region.
  • Data sheets do not necessarily match the actual specifications.
  • Customer support people do not know, nor care. They will sell you a 3-key for a full n-key. Yes, I am still bitter.
In the end, we are still looking for a cheap full n-key rollover keyboard with a USB connector. Perhaps a business opportunity?


The USB protocol limits the n-key rollover to a maximum of 6. There are now some USB keyboards that are capable of full n-key rollover, but only when the PS/2 adapter is used. Check out EliteKeyboards, they sell the Majestouch Tactile Touch NKRO, and Happy Hacking Keyboards.



Wow, that's really interesting! I never realized this problem I know why things don't always sounds right when I play certain chords on my PC keyboard.
jeeezuz....I want an IBM click clack model M Keyb so bad ...;=
I stumbled here looking for a "portable" keyboard for a laptop used for braille entry. (It's native keyboard doesn't do n-key rollover) In rummaging around and trying different ones, I found that the generic USB keyboard (DELL Model # L100) that they pack with all their lower-line desktop computers hopped right on the laptop with 6 key rollover support! These things oughta be EASY to find! Just looked and saw 7 or 8 of them on ebay for about $9 each! Hope it helps somebody!
Oh, for real? I think I have seen those keyboards at my university. I ought to check it with Renoise! Thanks for the help, Craig!
I actually did the same (saw those at my previous univ. computer labs and did a search) and ended up buying a pair from ebay. Dont remember exactly how it came out to be with shipping, but definitely cheap enough to be considered expendable. While these most certainly matched other stuff I have used in the past (some IBM membrane based model, some lower tier MS/logitechs), I found it somewhat lackin for my gaming needs. I play 2d fighters and have to press too many keys at the same time, I suppose.
2d fighters or tracking in Renoise: it all boils down to pressing more keys at the same time than the keyboard can handle. So konakona, are you saying the Dell L100 keyboard with its 6-key rollover is still inadequate? Then the search goes on...
Didn't know about this - interesting stuff. I think I might have one of those model Ms! Don't think i'll swap it with my mac keyboard tho - my guitar is the only thing that usually plays chords lol.
Yeah I noticed this problem right after I started my quest in computer musique and I've found a semi-solution There's this little app called Bome's Mouse Keyboard, you can program any chord with a single press of a key, helped me a lot: I just found this on stumble, it looks perfect for our needs :) It has full N-Key rollover according to their website :o
Oh, it's the revival of the IBM model M keyboard. Has a 12-key rollover. Hefty pricetag though, at $99 / $129.
Check this out, another IBM model M clone: I wonder if it actually has n-key rollover?
Apparently not the USB versions.... I bought the Unicomp Customizer USB version (manufactured on June 20, 2008) with the Windows keys: My keyboard passes the "cxer" rollover, but fails the "r-yu" rollover. Maybe the PS/2 versions would work. I need to go home and try my IBM keyboard (made by Lexmark in 1993) to see if it has a better performance in this regard.
I have a 104 keyboard, they're meant to have the license to the modem M technology. Their clones seem to be only 4-key rollover though.
The Kinesis Maxim seems to have full N-key rollover. At least using your little test above I can get up to 20 at a time by mashing down the keyboard with my hands. It costs between $120-140. On the other hand the more expensive Kinesis Advantage only has 6 key rollover. Disappointing considering its $300 price tag.
Yo, Maybe this is one: SteelSeries SteelKeys 7G Some testers said that its full rollover: hxxp:// cant test it myself - too expensive at the moment :)
There are a few keyboards out there now that support genuine N-key rollover. The Das Keyboard comes close, but it will have the same failing that ALL USB keyboards have - only six keys can be detected at once. However, it works around this by having an internal buffer... Once you release the first six keys, the next six are transmitted to the computer. I also hear the Logitech M15 can send the maximum (6) keys capable for USB, as can the Z-Board. Same with the Happy Hacking Keyboard. If you go the PS/2 connector route, you have some interesting possibilities. * The Cherry MX8100, which is a beast of a keyboard due to its target audience of Point-Of-Sale systems. It includes a trackpad and a slew of programmable keys, which would be incredibly useful for gamers. And a magstripe card reader, which isn't so useful. :) * The old IBM keyboards, PRE Model-M. Model M keyboards went the cheap route and have blocking issues with QWAS and similar key clusters, though you CAN type 'asdfjkl;' without any problems. However, the problem with the pre-Model-M keyboards is that they will almost exclusively have an unusual layout that would take forever to get used to... and no numpad. * The Filco Majestouch NKRO keyboards. These are new, genuine full-N-key rollover keyboards, with high-quality switches. Costly, though, but probably worth it. I may wind up getting one of these myself.
Thanks SparroHawc. Seems like there's a surge of very geeky, but also very expensive keyboards. I'm typing on a $7 keyboard right now. Do we really have to pay $150+ extra just to be able to get 6 characters through at once? Then again, I've also spent a lot of money on MIDI controllers I never use. Put in perspective, it may be worth spending a bit more on a keyboard that will be used a lot.
Why you spend so much time in investigating a proper keyboard with an n-key rollover? I mean yes that's geeky and fun at all (I was young too and remember the problem back then with fast tracker 2 / scream tracker 3 under DOS - do you know this one? ;) ) but when it comes to typing chords I use a MIDI-Keyboard via FireWire. N-Key rollover plus modulation wheels, knobs to play with... Ok, enough. Great work though. :D btw: I have a Logitech DiNovo Edge keyboard with an 3-key rollover.
Because some of us are used to play the computer keyboard really well,well before we had any "piano" keyboard. I have 2 5 octave keyboards but i still play better with the computer keyboard.You can do things like a C3-C4 arpegio with your thumb and index really fast and comfortable without stretching the whole palm,chords that are very comfortable to do,2 octaves with one hand,etc,plus drums.And it's THERE in front of you,you don't have to lift the fingers of the keyboard for the edits,play,stop,up down etc.I think the Filco NKRO looks like are MADE for trackers,full key rollover. It's the way I (really)like working with trackers.
:) @Sv4vS: Don't get me misunderstood. I've registered Renoise for exact this reason (nice wordplay) 'cause I own MBP and want to track ideas when I'm on the go just in time. But I prefer to "see" the "Klaviatur" in front of me and play it with my fingertips. I think that's just some personal preferation - nothing to get serious about it. And I don't play piano nor the keyboard very well. And as I checked the prices for the keyboards compared to some MIDI controllers, I saw that they're as expensive as really good let's call them tracker keyboards - that's all. I don't want to start a flame war here. :D
@ 3L : Sure thing mate,no flame war intended.I was just saying , some of us are used with playing the keyboard tracker style: 2 octaves.ZynnadSubFx has the same 2 octave input,so does fm8,massive and kontakt.AXS and other trackers too. Ahh,back in the day,Cakewalk 3 or so i think had this piano keyboard thingy that would let you set Q2W3ER5 etc for an octave,and the lower ones ZSXDCVG etc for another octave ,not adjacent.Keyboard split bliss,I want that in Renoise so bad....bass with th thumb,pad with the ring...ZynAdd still has this. It's strange I know.I can't even type well,but i can play string chords without looking at the keyboard. I think it has to do with 3 things: -being able to do chords that would stretch the hand a lot,like Q-T-N-I (c4-g5-a4-c6) for example,with one hand,easy -remembering very well the "chord",it has letters and it's in a easy to remember geometric pattern,diagonal,skip one,two,etc.Not having nkro sucks. -having the sequencer controls right on the "piano" Yes,no velocity,I Agreed,Tracker keyboards :) Peace
[quote] Ahh,back in the day,Cakewalk 3 or so i think had this piano keyboard thingy that would let you set Q2W3ER5 etc for an octave,and the lower ones ZSXDCVG etc for another octave ,not adjacent.Keyboard split bliss,I want that in Renoise so bad….bass with th thumb,pad with the ring…ZynAdd still has this. [/quote] not the perfect solution I know; but i guess you could try setting up a keyboard split like that in an .rni with multi samples, or in kontakt or similar, or eventually try sending midi out to an external synth with keyboard split or something like that i'm hoping we will be able to reassign all the keyboard buttons in the renoise Keys settings some day, because i have some alternative keyboard layouts i'm dying to recreate in renoise myself : D
ugh. I know from experience that making keys remappable is an utter pain. Doable, but it's a lot easier if you start out that way.
Raptor K1 Déck Keyboards One of those two will propably be my choice. Déck as first choice as it's backlit. Also AutoHotkey is a great program with remapping capabilites.
Ran across this thread and thought I should let you know that the Microsoft SideWinder X4 gaming keyboard is now out, and it features our new multitouch-based, anti-ghosting technology. As far as I know, this is the first low-cost, USB keyboard to allow extreme numbers of simultaneous key presses. You can find all the details here: For example, the keyboard accurately reports any 17 alphanumeric/navigation keys pressed simultaneously! And it does this via a standard USB connection. Here's the product page: Enjoy!
My Cherry G80-3000 (Soft) fails e-r-x-c Test. Come on, it costed me 50€ ... Not that I needed n key rollover, yet.
The Logitech G15 (the original version with 18 macro keys and blue backlight, not the new one with fewer macro keys and orange backlight) is not 6 key rollover capable. I just tested mine with Aqua's KeyTest, and with only WASD held down, there are 13 keys that will not register, meaning at best, this version is only 4-key rollover capable (plus most modifier keys, with the exception of caps lock). The keys it will not register with WASD held down are: Esc, F6, F10, F12, +/=, O, |/\, Caps Lock, '/", Left arrow, and 1, 2, and 5 on the numeric keypad. WASD is the only combination I've tested, it's possible it may not even be a full 4-key rollover.
Well, that's just great. Bloody expensive too, and now it's not even a 6-key rollover?
I think Keith is correct. My G15 (old version) can only do 3-key in some combinations. For example: tfgy - only 3 will register. Apparently Logitech's new G510 (which is basically the original G15, minus the hinge on the LCD screen, and plus colored backlighting) guarantees 5-key rollover, so that's an improvement at least. Still expensive though, and still not even 6-key rollover. Disappointing.
Deck's re sexxy. PERIOD. lol.
My Noppoo Choc Mini is full N-key rollover over USB, although it doesn't work with Mac OS X (it has full Windows compatibility, and Linux compatibility is pretty good; the only real problem on Linux is that the Caps-lock LED doesn't light when you turn Caps-lock on, and scroll lock doesn't work at all because who uses that anyway?) It's a fantastic small-form-factor keyboard at a much lower price than the Happy Hacking keyboard, and I recommend it highly.