Q. How quickly does the GNX4 switch between presets?
The GNX4 uses a microprocessor that runs at just under 200 MHz. This is more than 8x faster than previous GNX products.
This increased speed performance does not exactly correlate into how much faster the GNX4 changes presets, but typically the preset change times are 70 to 80 milliseconds.
However, this processor is also responsible for running the 8-track on board recorder/looper and running the drums/mp3. Under the worst-case condition (8 tracks of audio looping and an MP3 playing simultaneously), the preset change time will increase a bit.

Q. Can I use an external hardrive/mp3 player such as my IPOD for MP3 playback and backing tracks instead of the internal Compact Flash?
It is possible to plug an external mp3 player into the GNX4 using the Line inputs. When using the Line Inputs you need to check the routing as follows:
1. On the Recorder Panel press the Shift button.
2. Press the LINE button.
3. Use the Data Wheel and select Line Dry.
You should now be able to hear the IPOD playing through the GNX4 outputs depending on which Output Setup you are using.Q.

Q. How much recording time can a 2Gb card support?
6 hours 24 minutes.
(see also, additional chart)

Q. Can I use a Type I or Type II Compact Flash card?
The GNX4 supports only Type I cards. Type II cards and Micro drives are not supported.

Q. I understand that I will be able to record up to 4 track via the USB to my computer, BUT am I also able to record 4 tracks or instruments, each to their own track, to the compact flash card?
Example (with no computer...files will be transferred to the computer later, but the gnx4 is all I will have at this session):
-Track 1 - Vocal
-Track 2 - Electric Gtr
-Track 3 - Keyboard (mono)
-Track 4 – Bass
The GNX4 can record 4 channels of Audio up the USB pipe simultaneously. You can have two tracks playing back from the computer while doing so (most likely a stereo mix of your project)
However, only 2 tracks can be recorded at a time using the onboard Compact Flash Recorder. This limitation is required for the capability of having 8 tracks playing back simultaneously and handling each playback track individually.

Q. Anyway to control the drum machine / mp3 / MIDI playback from the foot controller - other than from Record mode. I often want to be in Preset or Stompbox mode, but also want the ability to start and stop a song (MP3, Drum loop, etc.). Can you do it with the optional DigiTech foot controller?
Yes, these functions can be controlled with the optional GNXFC.

Q. Does the read/write speed of the CF card matter at all? I've not used them before and they all say they have different read/write speeds. Is it just a case of the faster the better?
Even the slowest cards should allow playback of MIDI and mp3 files. The CF card speed is a consideration when recording and playing back multiple tracks. We tested many cards of different speeds and grades and didn't find a problem when using standard speed cards. Note that speeds are manufacturer dependent, and unless speeds are clearly labeled, we can't guarantee that a CF manufacturer won't make a card that is too slow.
The CF card has to be formatted using Fat16 in order for it to work in the GNX4.Check this first if your card doesn't seem to work. The GNX4 can perform a format through the Song Setup menu.

Q. Can you customize your own drum pattern (hit snare, or cymbal at a set time etc)?
The GNX4 drum machine will play back any custom MIDI file from either a sequencer application via USB or if the MIDI file is placed on the Compact Flash card. You can trigger any of the internal MIDI drum samples in the GNX4’s drum kits. The MIDI information must be mapped to channel 10. Any MIDI files to be played back from the Compact Flash card must be type 0 files, meaning all MIDI messages must be in a single track and not separated into different tracks as can be done using type 1 files.

Q. Why does the GNX4 have USB 1.1 and not 2.0? Is that upgrade possible by updating the firmware? If yes, is that going to be the case one day?
Right now USB 1.1 is a very good fit for the GNX4 because the four audio inputs to the product can be recorded simultaneously while playing back an entire mix. The GNX4 also allows you to have a USB MIDI port available for playing back drums to the GNX4's on board drum machine or using an external general MIDI module plugged into the GNX4 MIDI jacks. Also, DigiTech's X-Edit GUI allows you to have the app running while streaming audio. There is also a USB Mass Storage Class function "Compact Flash Storage" for transferring files between the compact flash card and the computer (built in card reader).
The standards for USB 2.0 audio spec are not final. Anyone who is implementing this is writing custom drivers. The GNX4 is compatible with computers that have USB2.0 ports. The GNX4 will run at full speed (12 Mbps bandwidth).

Q. Is there a way to adjust the direct signal level when mixed with the effects? For example, it is possible to only hear the reverb caused by the direct signal, rather than the guitar signal + reverb. This ability has been useful to me with other effects processors for creating "organ" or synth like sounds.
Some GNX4 effects (Whammy, Rotary Speaker, etc..) have a MIX parameter rather than a level parameter. Turning these MIX parameters to 99 will remove any dry signal and only pass the effect signal.