How to make a custom IR ?

[Marshall]

It worked well at home. Whereas a simple 9V disposable battery will not turn the pedal on. I will only plug one thing (the NUX) into the battery.

That's an interesting discussion on voltages. I figured something like that had to be going on.

[Marshall]

I’ve used the rig out twice now. It works well with the battery. I use a wireless radio cord from guitar into the NUX. Then take the house 1/4” into the out of the NUX. Works great. Quick and easy. I wouldn’t use the battery for a long gig/set. But for quick up and downs it’s great.

[jonfields45]

Originally Posted by Marshall

I’ve used the rig out twice now. It works well with the battery. I use a wireless radio cord from guitar into the NUX. Then take the house 1/4” into the out of the NUX. Works great. Quick and easy. I wouldn’t use the battery for a long gig/set. But for quick up and downs it’s great.

The standard 10,000 mAh NCMA Lithium battery is ~37 watt-hours. Should run your NUX 10+ hours. Certainly gig worthy. The reviews on Amazon indicate the failure rate is low (not zero, but neither is the name brand competition).

Regrettably my UA American Dream draws a bit more than 350 mA (I measured it) which blows out the 300 mA spec.

[Marshall]

Here's my quick jury rigged setup





There are spaces below and above the battery. I don't want reduced airflow to give rise to overheating of the battery.


Worked great twice in the last couple days.

[jonfields45]

Originally Posted by Marshall

Here's my quick jury rigged setup





There are spaces below and above the battery. I don't want reduced airflow to give rise to overheating of the battery.


Worked great twice in the last couple days.

Here's a pic of my setup. I soldered a 5.5/2.1mm DC connector directly onto the 9 volt USB trigger cable. I velcro'ed the battery to the side of the pedal.

Small Cell Phone Power Bank 10K mAh (~37 watt-hours):
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

USB C Trigger cable tells Power Bank what voltage to deliver and provides that output positive tip 5.5/2.1mm DC (stomp box standard, but wrong polarity). Select the 9 volt version.
https://www.ebay.com/itm/11452516501...3ABFBMxuLOxv9i

[lkingston]

I got this power supply a little cheaper on eBay. It is small, metal construction, goes for hours, and lets you know how much power you have left (the power switch changes color from green to red as the power is depleted):

https://www.amazon.com/Tomsline-APW-.../dp/B01GV0P5V6

[lkingston]

I find the NUX Optima Air is really great for capturing IRs. You can use them on the Helix and they sound the same.

The problem with the NUX Optima Air for me is that it doesn’t let you blend the IR with the direct sound. A Fishman Aura doesn’t have as good IRs as you can capture on the Optima Air, but you can blend them.

[jonfields45]

Originally Posted by lkingston

I find the NUX Optima Air is really great for capturing IRs. You can use them on the Helix and they sound the same.

The problem with the NUX Optima Air for me is that it doesn’t let you blend the IR with the direct sound. A Fishman Aura doesn’t have as good IRs as you can capture on the Optima Air, but you can blend them.

You can edit the IR to add blend. Read the IR wave file into a DAW. I own Reaper but prefer Audacity for ease of use. Select the entire waveform and reduce its volume by half (this is a bit arbitrary…). Then zoom in on the first sample. Select that sample and double its amplitude. Save it to a new wavefile. Reverse the change to the first sample and repeat for gain adjustments of 1.5, 2.5, and 3.

You now have a collection of bypass blended IRs. They are not volume equalized like the ones my script generates, but they all have the same timbre for the IR component of the blend.

If there’s interest I can write an Octave script to generate a family of volume matched blended IRs from any existing IR wave file with an exact blend label.

[lkingston]

Originally Posted by jonfields45

If there’s interest I can write an Octave script to generate a family of volume matched blended IRs from any existing IR wave file with an exact blend label.

I would certainly be interested in such a script. Maybe one that could normalize at the same time.

[jonfields45]

Originally Posted by lkingston

I would certainly be interested in such a script. Maybe one that could normalize at the same time.

I’m out of town for a week and will take care of it when I get back.

[Cuki79]

Originally Posted by lkingston

I would certainly be interested in such a script. Maybe one that could normalize at the same time.

I have a MATLAB script that does that and normalizes with respect to the loudness (ISO 532-1) and not peak amplitude.

I just don’t have the time these days to translate in python and post.

[jonfields45]

Originally Posted by lkingston

I would certainly be interested in such a script. Maybe one that could normalize at the same time.

Would you prefer Python or Octave?

[jonfields45]

Originally Posted by jonfields45

Would you prefer Python or Octave?

I’ve cobbled together a script in Octave on my iPad. There’s no easy way to test it. It runs essentially the same way as my IR generator. I’m not home until Sunday. I’ll let it stew overnight and post it here.

[jonfields45]

I ran the new Octave script remotely on my home Mac using AnyDesk and it runs without obvious error. In the Google Drive directory link below you will find a sample IR wave file (jf45irPWFS.wav), the new script (jf45irbpbl.m), and 11 new blended files with a RMS amplitude of 1 (wave files are a series of fractional numbers between zero and one).

https://drive.google.com/drive/folde...VqDuK5DOVV_KKc

For the particular IR sample in that directory, the command line is (the single quotes need to be vertical which is no problem in Octave but somehow MIA on my iPad’s virtual keyboard):

Jf45irbpbl(‘jf45irPWFS’)

I’ll check them out for how they sound when I get home on the weekend.