While you are deciding which impulse response (IR) cabinet files to use in your DAW plug in, software based, or hardware based amp modeler that uses IR files, you may come across some terms from the recording industry that are used by different IR providers: remastering and re-recording.
What is the difference between Re-recording versus Remastering when applied to guitar or bass cabinet impulse response (IR) files?
Re-recording may be defined as literally getting the cabinet back into the studio, placing the mics at different positions on those cabs again, making the recording, deconvolution of the recordings were completed again, file management and re-organizing those files were completed again. This is basically telling you that any earlier recordings were scrapped in favor of new and improved recordings of the cabinets as IR files.
Remastering may be defined as taking existing recordings and altering their tonalities with one or more of the following processes, EQ or frequency equalization, multi-band compression, noise reduction, and/or re-sampling or re-dithering the recorded wave forms, just as major record labels would do when converting recording from the vinyl era, to the CD era, to the multi-channel surround sound era, to the streaming era in order to optimize the listening experience for those different mediums.
Why make the decision to re-record versus remaster cab impulse response (IR) files?
What would make an IR provider re-record impulse response (IR) files? I can only speak for myself as I cannot climb into another IR provider's mind to give you others' insights. I have only chosen to re-record three impulse response (IR) cabinet file packs to date (29 May 2018) and that was usually due to some eureka moment that I had with the physical cabinet at a later date when I realized different mic placement, etc. could yield superior results in capturing the tonal reality of that cab with those mics. Another reason, such as with the Aguilar 8X10, is that the original cab was shot with one business understanding of supporting one file format, but when my business model changed, I had neither the access to the same cab nor the original convoluted files in order to render a complete collection in a file different format. Please note: every time I have re-recorded a cab pack, I have reached out to those who purchased though this site and have provided the re-recorded files free of charge as an upgrade!
What would make an IR provider remaster impulse response (IR) files? Personally, I would never make the the decision to remaster IR files due to the fact that by the very nature of using EQ or frequency equalization, multi-band compression, noise reduction, you are introducing phase shifts to the signals that can affect the quality of your recordings. Since you are already using tone controls of your amp emulator and time based effects, you are already introducing phase shifts to your original performance signal. Using the gain controls of the simulator and any effects, you are already introducing some audio signal compression to your original performance. Since I cannot use psychic powers to predict how much EQ, gain, or compression you will be using before using my IR files, I would not want to further change the reality of your art, since a cab recorded under the best circumstances is going to change the frequency and timbre of your performance. You would have to ask a provider who touts remastered files rather than re-recorded files why they took a path that compromises the quality of the signal.
If remastering is good enough for music, why isn't remastering good enough for bass or guitar cab impulse response (IR) files?
Music performances are generally regarded as historical events. Artists came together with a certain era of technology, with a skill set frozen at the time of that performance, in a certain environment, and created art. Whether it's Slayer's "Reigning Blood", John Coltrane's "Giant Steps", or La Roux's "Bulletproof", there's a certain audio alchemy involved where we don't ask artists to re-record & re-mix art as it would inevitably alter the art performance historically, especially when tech progresses, skills increase or decrease, or performers shuffle off this mortal coil.
In the case of musical performance, we view remastering music as a sort of audio version of restoring the art of the Sistine Chapel. In a way we are enabling the audience to experience the art anew for a new generation without needing to attempt to recreate the art using different artists.
When it comes to recording impulse responses, you really are not dealing with artist performances but with inanimate objects performing a function they were engineered to do millions of times without fail. You are dealing with a speaker cabinet, which usually can be re-acquired with little pain, recorded again, without worrying about recreating a performance of an artist. We are not talking about recording 64th note arpeggios at 200 bpm tempi by instrument masters when we are talking about re-recording IR files, we are talking about re-recording frequency sweeps.
It is a long and sometimes tedious task to re-record, as the IR provider is laboring over 0.005% tonal quality differences sometimes when comparing files for the release version to use. But, as IR providers, that is the job we perform so that you can get down in minimal time to the business of finding what works for you and making art.
I hope this helps you make more informed decisions when choosing from all the cabinet impulse response (IR) files out there. There is a lot of good stuff and there is also a bunch of compromised stuff out there. Hopefully, this essay helps you ask the questions to make the right decision for your art.