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Redesigned MIDI Expression iO

Posted: Wed Dec 01, 2021 12:35 am
by Rob
MIDI Expression iO
This is the latest generation of the MIDI Expression iO, a 4 input USB pedal to MIDI interface with full-size MIDI in / out ports for USB or standalone operation.
Click image to rotate.
Rock Solid
Outfitted in an all aluminum enclosure, the MIDI Expression iO is strong and sturdy. Non-slip pads on the bottom of the device keep it from moving around.

Improved Resolution
The addition of opamp buffers on each pedal input, provides the finest resolution of any MIDI Expression device to date, even when using high-impedance expression pedals.

Expanded Compatibility
With an upgraded power delivery configuration, the iO can now supply up to 30 mA of current at 3.3V to easily power Hall effect sensors, photo-sensors are any input that requires power from the jack.

Re: Redesigned MIDI Expression iO

Posted: Wed May 11, 2022 11:38 am
by bblix
Received the unit this week.

A significant improvement in all areas!

The box is solid and of industrial quality and the added flexibility the 9v input offers is super!

I hooked it up to my 3 Yamaha FC7s and one dual footswitch - and everything fell into place without user intervention or calibration - amazing.

I've used several MIDI Expression products in various contexts since ordering my first Solo unit in 2013 and the development through the years has been fantastic!

Thank you!

Best regards,

Brynjulf Blix

Re: Redesigned MIDI Expression iO

Posted: Wed May 11, 2022 11:23 pm
by Rob
Thanks for positive review. There's 10 years worth of RnD packed in there.

Re: Redesigned MIDI Expression iO

Posted: Tue Jun 07, 2022 9:41 am
by HCMarkus
Solid. Love it. I have the plastic quad one, too, which has performed great on the road. Thanks for making these!

Re: Redesigned MIDI Expression iO

Posted: Sat Aug 27, 2022 9:45 pm
by coustard
I've just received mine (2, in fact). I've been using the plastic versions in a keyboard rig for year now and they've stood up to the rigours of the road with no issues whatsoever (and I'll confess, I did worry a bit) but the new version is a better form factor for mounting on a pedal board and the aluminium enclosure feels like it'll last forever.

Great work, Rob. For my needs, at least, along with the configuration app this is pretty much a perfect product.

Re: Redesigned MIDI Expression iO

Posted: Thu Jan 05, 2023 4:12 am
by stub
It says higher resolution, but I couldn't find any mention in the description or specs. Is it 16 bit ADC? Or can it generate full 14-bit CC? Can it do this for all 4 inputs?

Re: Redesigned MIDI Expression iO

Posted: Thu Jan 05, 2023 4:35 am
by Rob
The ADC reads at 14 bits for all 4 inputs. There's always a bit of noise in that measurement, but a well make pedal should get around 12 bit effective resolution. The sensitivity control adjusts how loosely that noise is filtered.

Re: Redesigned MIDI Expression iO

Posted: Fri Jan 06, 2023 2:45 am
by stub
I have a couple precision 3-turn pots (10K), some Force-Sensing Resistors, and (hopefully) a working breath control circuit that I've wanted to use at higher res. Thanks!

Re: Redesigned MIDI Expression iO

Posted: Fri Jan 06, 2023 6:39 pm
by stub
The MIDI Expression manual doesn't go into much detail about 14-bit use.

I see a reference to NRPNs, but nothing about just plain old 14-bit CC's where the CC's are in pairs of MSB and LSB, 0 & 32, 1 & 33, etc.

Does the MIDI Expression iO work this way as well? Can you tell it to be in 14-bit mode, and assign the first CC as say 9 and it will automatically generate the LSB on CC 41?

Or will it only work if we set up a NRPN.

Are there any plans for some MIDI 2.0 features?

Re: Redesigned MIDI Expression iO

Posted: Fri Jan 06, 2023 11:44 pm
by Rob
Currently MIDI Expression does not support 14bit control change messages for controllers (0-31), but instead support NRPN as mentioned in the manual. Does anyone support 14bit CCs? If there's a real use case for it, I might be willing to implement that.

As for MIDI 2.0, when low-level driver support comes to Windows / macOS / Linux, MIDI Expression will eventually support it. Unfortunately, there's no such thing as a class compliant MIDI 2.0 device at the moment.