Zen Guitar
Member
I have recently began creating custom blends of impulse responses within my DAW and outputting the resultant composite IR's to be used in my Axe-Fx Ultra.
I have had good success throughout all of the steps, until I get to the "wav to sysex conversion" and "upload to Axe-Fx" stage. I am able to do both the conversion and the upload, but the results do not sound correct. I am hoping that some of the experts here might have some insight to offer.
My process has been to create a 24bit 48k session in Pro Tools and create a number of aux tracks, being fed in parallel by my Axe-Fx Ultra. On each of these aux tracks, I insert an instance of TL Space (my convolution reverb program) and load an appropriate IR from my Redwirez library. I then set levels and panning to taste, as I would in a traditional recording session. Once I've got something I like, I send an impulse trigger along a bus to these aux tracks and record the result as a stereo file. I then normalize and trim the IR.
To ensure that the IR was created properly, I reimport the new composite IR into another aux track and A/B the results of sending my Axe-Fx through this and the multi-track IR set-up.
I then bounce the file down as separate mono 24bit 48k wav files for the left and for the right sides of the stereo composite IR.
Everything up to this point has worked ideally.
My desire is to load each of these into a separate User Cab slot and to run two mono hi-res cab blocks using each these IR's in parallel, each hard panned, so that I can replicate the sound of the stereo composite IR within a patch.
I have been successful in both converting the individual IR's to sysex as well as loading them into the appropriate User Cab slot in the Axe-Fx using Albert's IR Converter. However, the result has yielded what sounds like the two halves of the IR (each in their own Cab block) are now somehow out of phase with each other.
I've tried sending the IR's to the Axe-Fx both by first separately converting to sysex then uploading, and alternately by opening the wav file and just clicking "upload." The results are quite different for some reason, but neither sound correct. FYI, when comparing the graph's of the wav versus the sysex version of the file, the phase plot looks similar, but different.
I've attempted to troubleshoot the process as much as possible on my end before asking for help. I've been able to verify that the composite IR (before conversion) works as it should, the Axe-Fx is outputting its left and right signals in the proper phase when not using these new composite IR's, and that no other setting or factor outside of the conversion and upload process can be found suspect.
I've created waveforms of the Axe-Fx using both guitar playing as well as a 1kHz sinusoidal test wave sent through a blank patch with only two cab blocks in parallel, each hard panned and each loaded with one half of the stereo IR (left on one side and right on the other). I've compared the waveforms of the patch with the cab blocks active, and also with the cab blocks bypassed and then run through the composite IR in my DAW. The former sounds out of phase between the left and the right sides (similar to the effect of placing too much stereo enhancer on a stereo track or delaying one side slightly, with the effect being more noticeable when playing certain notes) and the waveform shows that the left and right are not in proper phase alignment (although there seems to be no delay between the start of one side versus the other and they do not seem to be in perfect polar reversal). The track using the composite IR in the DAW both sounds and looks as it should.
Edit: After further troubleshooting, I'm finding that there is a certain amount of this "phaseyness" on each mono IR after loaded into the Axe, even when soloed, and so not simply a matter of the relationship between the left and right sides (although this is also an issue). Once again, this seems more apparent at certain frequencies or when playing certain notes (bending the low F# up to G on the low E string is a common focal point with its octaves have similar, although lesser effect). Frequency dependent phase issues? After double checking the IR's again in my convolution program, I still see no sign of these issues. I wondered if anything had to do with the truncation in the Axe to 1024 samples, so created truncated versions to re-import into my convolution program. This had no effect on the "phaseyness," although it did make me appreciate what a longer sample length IR offers. ;-)
At this point, I am simply guessing that something as part of the conversion and/or upload process is causing the files to change. I am only guessing here and have no idea as to how address the issue.
Any insight and help would be greatly appreciated!
Also, if anyone can recommend an alternate wav to sysex conversion utility (I'm on a Mac) so that I can test this part of the process as well, I'd be grateful.
I want to stress that I am very grateful for Albert's IR Converter and all of his hard work in creating that as well as his other numerous contributions to this community. I am not trying to insinuate that it does not work properly, I am just trying to present what I know in detail so that the experts here can have as much information as possible to make assessment and recommendations.
I'd also like to say quickly that the blends I have been able to come up with so far with the Redwirez cabs that I have are sounding really great. I'm very excited by the possibilities and am hoping that I can get past this last hurtle and get it all working in time for some upcoming recording.
Thanks in advance to everyone wishing to help out on this!
-Matt
I have had good success throughout all of the steps, until I get to the "wav to sysex conversion" and "upload to Axe-Fx" stage. I am able to do both the conversion and the upload, but the results do not sound correct. I am hoping that some of the experts here might have some insight to offer.
My process has been to create a 24bit 48k session in Pro Tools and create a number of aux tracks, being fed in parallel by my Axe-Fx Ultra. On each of these aux tracks, I insert an instance of TL Space (my convolution reverb program) and load an appropriate IR from my Redwirez library. I then set levels and panning to taste, as I would in a traditional recording session. Once I've got something I like, I send an impulse trigger along a bus to these aux tracks and record the result as a stereo file. I then normalize and trim the IR.
To ensure that the IR was created properly, I reimport the new composite IR into another aux track and A/B the results of sending my Axe-Fx through this and the multi-track IR set-up.
I then bounce the file down as separate mono 24bit 48k wav files for the left and for the right sides of the stereo composite IR.
Everything up to this point has worked ideally.
My desire is to load each of these into a separate User Cab slot and to run two mono hi-res cab blocks using each these IR's in parallel, each hard panned, so that I can replicate the sound of the stereo composite IR within a patch.
I have been successful in both converting the individual IR's to sysex as well as loading them into the appropriate User Cab slot in the Axe-Fx using Albert's IR Converter. However, the result has yielded what sounds like the two halves of the IR (each in their own Cab block) are now somehow out of phase with each other.
I've tried sending the IR's to the Axe-Fx both by first separately converting to sysex then uploading, and alternately by opening the wav file and just clicking "upload." The results are quite different for some reason, but neither sound correct. FYI, when comparing the graph's of the wav versus the sysex version of the file, the phase plot looks similar, but different.
I've attempted to troubleshoot the process as much as possible on my end before asking for help. I've been able to verify that the composite IR (before conversion) works as it should, the Axe-Fx is outputting its left and right signals in the proper phase when not using these new composite IR's, and that no other setting or factor outside of the conversion and upload process can be found suspect.
I've created waveforms of the Axe-Fx using both guitar playing as well as a 1kHz sinusoidal test wave sent through a blank patch with only two cab blocks in parallel, each hard panned and each loaded with one half of the stereo IR (left on one side and right on the other). I've compared the waveforms of the patch with the cab blocks active, and also with the cab blocks bypassed and then run through the composite IR in my DAW. The former sounds out of phase between the left and the right sides (similar to the effect of placing too much stereo enhancer on a stereo track or delaying one side slightly, with the effect being more noticeable when playing certain notes) and the waveform shows that the left and right are not in proper phase alignment (although there seems to be no delay between the start of one side versus the other and they do not seem to be in perfect polar reversal). The track using the composite IR in the DAW both sounds and looks as it should.
Edit: After further troubleshooting, I'm finding that there is a certain amount of this "phaseyness" on each mono IR after loaded into the Axe, even when soloed, and so not simply a matter of the relationship between the left and right sides (although this is also an issue). Once again, this seems more apparent at certain frequencies or when playing certain notes (bending the low F# up to G on the low E string is a common focal point with its octaves have similar, although lesser effect). Frequency dependent phase issues? After double checking the IR's again in my convolution program, I still see no sign of these issues. I wondered if anything had to do with the truncation in the Axe to 1024 samples, so created truncated versions to re-import into my convolution program. This had no effect on the "phaseyness," although it did make me appreciate what a longer sample length IR offers. ;-)
At this point, I am simply guessing that something as part of the conversion and/or upload process is causing the files to change. I am only guessing here and have no idea as to how address the issue.
Any insight and help would be greatly appreciated!
Also, if anyone can recommend an alternate wav to sysex conversion utility (I'm on a Mac) so that I can test this part of the process as well, I'd be grateful.
I want to stress that I am very grateful for Albert's IR Converter and all of his hard work in creating that as well as his other numerous contributions to this community. I am not trying to insinuate that it does not work properly, I am just trying to present what I know in detail so that the experts here can have as much information as possible to make assessment and recommendations.
I'd also like to say quickly that the blends I have been able to come up with so far with the Redwirez cabs that I have are sounding really great. I'm very excited by the possibilities and am hoping that I can get past this last hurtle and get it all working in time for some upcoming recording.
Thanks in advance to everyone wishing to help out on this!
-Matt
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