The keyboard enthusiasts forum at geekhack.org has an extensive list of keyboards tested for their N-Key-Rollover capabilities, as well as instructions on how to find the number of simultaneous keypresses a certain keyboard supports.
X-key-Rollover (where X is an integer smaller than the number of physical keys) is the minimum number of keys that will register correctly under any circumstances. True N-key-Rollover (NKRO) means that all keys can be held down and register correctly. Most standard keyboards offer only 2KRO, and although it is possible that certain key combinations allow more keys to register simultaneously, this is not guaranteed, and may differ even between different revisions of the same keyboard.
You can purchase gamer keyboards at retail stores. You need to look on the box for “[howmany] key roll-over”, and “anti-ghosting” features. Beware that some keyboards have anti-ghosting only for a limited set of keys. That won't work for the KeyMusician Keyboard. It needs anti-ghosting on all of the keys.
The table below is a list of keyboards having a confirmed NKRO over a PS/2 connection, or 6KRO/18KRO over USB (which is a USB limitation), from the geekhack.org forum thread (June 5th, 2012).
Note: Some keyboards not having a numeric keypad (which is essential for the KeyMusician Keyboard) have been removed from the list, and a few entries with confusing (or lacking) info were deleted.
I have personally tried only the Microsoft Sidewinder X4 keyboard, which I like, and recommend.
A 6-key roll-over value (6KRO) is probably adequate for playing the KeyMusician Keyboard in chords+melody mode, because you play probably at most 4 simultaneous keys with your left hand, and need the capability of 2 simultaneous keys with your right hand on the numeric keypad. If you improvise with both hands on the melody-portion of the keyboard, 6-key roll-over won't be enough.
If you play pieces entirely on the melody-portion of the keyboard, 8-key roll-over might be enough, but you could need 10-key roll-over.
Keyboard Name |
USB Interface |
PS/2 Interface |
Adesso MKB-125B |
6KRO with USB cable adapter |
NKRO with PS/2 |
Adesso MKB-135B (full sized) |
6KRO with USB cable adapter |
NKRO with PS/2 |
Cherry G80-3494 (Cherry Red) |
6KRO with USB |
NKRO with PS/2 adapter |
Cherry G80-3600 (Cherry Red) |
6KRO with USB |
NKRO with PS/2 adapter |
Cherry Corp G80-8200lpdus |
|
NKRO PS/2 |
Cherry Corp MX8100 G80-8113LRCUS-2 |
|
NKRO PS/2 |
Cherry Corp G80-8113HRBUS-2 |
|
NKRO PS/2 |
Cherry Ergoplus G80-5000HAMDE/03 |
|
NKRO PS/2 |
Das S |
6KRO under USB |
NKRO with PS/2 purple adapter |
Das 3 (previous model) |
12KRO under USB |
can not be used with PS/2 |
Deck Legend |
6KRO under USB |
NKRO under PS/2 |
Deck 82 Key |
6KRO under USB |
(no PS/2 option) |
Ducky keyboards |
6KRO under USB |
NKRO with PS/2 adapter |
Ducky G2 keyboards (special edition) |
18KRO USB |
NKRO PS/2 |
F21-7d Mechanical Keyboard |
6KRO over USB |
(no PS/2 option) |
Filco Keyboards Listed as NKRO |
6KRO under USB |
NKRO with PS/2 |
G-Tune Realforce 108B-MP |
|
NKRO over PS/2 |
IBM Model F AT |
|
NKRO AT/PS/2 adapter |
iRocks KR-6230 |
6KRO with USB |
|
KBC Poker |
6KRO with USB |
NKRO with PS/2 adapter |
Key Tronic KB101 Plus |
|
NKRO PS/2 |
Leopold FC500R (FullSize) |
18KRO USB (Windows/OSX/Linux) |
NKRO with PS/2 |
Marquardt MiniErgo |
|
NKRO PS/2 |
Matias Tactile Pro 3.0 |
6KRO USB |
|
Microsoft Sidewinder X4 |
18KRO over USB |
|
NCR Cherry G80-0528H/10 |
|
NKRO PS/2 |
NEC APC-H412 |
|
NKRO PS/2 |
Noppoo Chocolate Pro (fullsize) Full |
NKRO under USB |
NKRO PS/2 |
Northgate Omnikey 101 and CVT Avant Stellar |
|
NKRO PS/2 |
PFU Happy Hacking Keyboard |
6KRO under USB |
Can not be used with PS/2 adapter |
Qpad MK-80 (Cherry blue) |
6KRO with USB |
NKRO with PS/2 adapter (included) |
Qpad MK-85 (Cherry red) |
6KRO with USB |
Can not be used with PS/2 adapter |
Raptor Gaming K1 |
6KRO under USB |
Can not be used with PS/2 adapter |
Rosewill RK-9000 (Gen1 nonremovable cord) |
6KRO USB |
NKRO with PS/2 adapter |
Rosewill RK-9000 (Gen2 removable cord) |
6KRO USB |
NKRO with included PS/2 cable |
Steelseries 6G Version 2 7G |
6KRO USB |
NKRO with PS/2 adapter |
Thermaltake Meka G1 |
6KRO under USB |
NKRO with adapter |
Topre Realforce |
6KRO under USB |
Can not be used with PS/2 adapter |
XArmor U9BL |
6KRO thru green USB adapter |
NKRO under native PS/2 |
XArmor U9BL-S (Cherry Brown) |
6KRO USB |
NKRO with included PS/2 adapter |
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