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Dobro - creating an IR from a preamp/sound-imaging pedal


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Hey all, total HX Stomp noob here. I was wondering if anyone could offer me some advice in how to do a particular thing - I want to create an IR from a sound imaging pedal I use for my dobro to load into the HX stomp. This is the pedal I'm trying to model: https://www.fishman.com/wp-content/uploads/2019/04/Jerry-Douglas-Imaging-Pedal-User-Guide.pdf

I would assume there is a way to create an IR from this pedal using a sine wave sweep and Logic's Space Designer, but I don't know exactly how to do that. Maybe there's an easier way, too! I know there are existing downloadable dobro patches that are designed for electric guitar, but I'd really like to be able to essentially make a print of the Fishman pedal and load it into the HX Stomp for use with my dobro (and banjo). I'm trying to simplify my fly-rig and I got the HX Stomp hoping I could do exactly this with it. Any and all help and suggestions would be appreciated! Thanks

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Logics Space Designer is pretty much straight forward. Connect the output of your audio interface to the pedal, run the pedal output into your interface and you should be good to go. The resulting file will be an "SDIR" which you can convert to AIF/WAV within Logic.


Possible arising issues:

- The pedal might do some dynamic stuff. Dynamic processing can't be captured with IRs.

- The pedal might add some spatial information longer than 2048 samples, which is the maximum IR length the HX series can deal with.

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Fwiw, otherwise, in case you only wanted the frequency imprint of the pedal, you could as well use Logics Match EQ to get there. Record both the clean and the effected signal parallely (in case you can, but the HX Stomp should serve you fine in doing so), place the Match EQ on the effected track, use the clean track as a source for the Match EQ. You might want to do fine adjustments after that. When done, remove the effected part and place a neutral spike IR (aka "dirac") on that track, run it through the EQ and export. You might need to trim the resulting file (which will then become your IR).

Note: This will really only work in the frequency domain, anything in the time domain (which could be relevant, even if we're just dealing with a maximum length of 2048 samples) will be ignored.

The good thing about this method is that you can easily compare things and do some adjustments. I'd do it that way even if you'd shoot an SDIR beforehand, too, just for a little polishing and what not.

In case you've got no dirac IRs, I attach a whole bunch of them in all common samplerates, mono and stereo.


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And fwiw: I'm using the dirac method to mix and match IRs of all sorts since years pretty successfully. Didn't only mix cab IRs but also created my own "acoustic resonance" IRs to enhance my piezo equipped acoustics or to steal the frequency imprint of some guitar recordings (again using the Match EQ).

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If the intent is to plug your dobro straight into the Helix, you need to make sure you can match the impedance of the Fishman pedal as well as the IR.  (Eq shouldn’t be a problem.). The Fishman pedal is specifically designed for piezo pickups used in the Beard dobros, which require a very high impedance input.


if you have ny success, please let us know!  I’ve been plugging my RedBerd into the Fishman pedal, then at times going from that to my HXFX.



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On 9/21/2022 at 2:48 AM, PierM said:

Should be definitely possible, and I remember Codamedia did something similar with success.


I sure did... I've created IR's from every setting in the JD Aura and my favorites from the standard Fishman Aura. It works 100% and it saves me from carrying around extra gear. 


On 9/20/2022 at 8:29 PM, a_hall_62 said:

I would assume there is a way to create an IR from this pedal using a sine wave sweep and Logic's Space Designer, but I don't know exactly how to do that.


I used Voxendo Deconvolver (free version) and followed their basic instructions. 

  • Create 13 MONO Tracks in the DAW.
  • Start by recording a 12 second sweep... Deconvolver gives you the signal, just record it in the DAW.
  • Set the pedal so the only thing you are capturing is the effect tone... no blend, no added compression, etc... etc... 
  • Play the Sweep tone you created back into the pedal, and record it's output on a separate track
    • NOTE: The two sweeps should be identical in start time, end time and length. They just sound different and appear on their own tracks. 
  • Repeat this process for each setting on the pedal
  • Export the original sweep as the "ORIGINAL FILE"
  • Export each of the other sweeps...
  • Run those files through Deconvolver to create the IR
  • Trim the IR to the correct length. I used SoundForge for this, but you can use Logic as well. 
  • I believe I exported the final to 48/24... but don't really remember for sure. All I know is they sound just like the pedal did. 


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On 9/23/2022 at 10:53 AM, loonsailor said:

Cool!  Do you plug directly into the Helix or use a DI for impedance match?  If direct, guitar in or return?


I plug straight into the INSTRUMENT input on the Helix.... my impedance is FIXED at 1M for all of my presets other than my BANJO which I set to something lower, but I can't recall at this moment. My DOBRO has a passive Fishman PIEZO... and I do have that preset set to 1M. 


IMO... Start with an input imp of 1M... if it's too bright for your liking, lower the impedance until you get the tone you desire. The IR itself is not going to care about impedance, it just wants a nice signal to work with. 


On 9/23/2022 at 10:53 AM, loonsailor said:

are you willing to share the IRs?


I have never had a problem sharing something I use, as long as it's legal and moral. In the past I didn't want to share "Fishman's" work, but as it's been pointed out to me... I had to rebuild it, and it might not have the exact same results (although I do appear to get the same results). 


I can't seem to attach a ZIP file so here is the LINK to download the ZIP

(MOD's... if this is not permitted, please just let me know and I'll remove the link)

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