Hardware IR process question

Question

Level 1

11 points

Hardware IR process question

Hi - I'm new on here. Have been using Logic 8 for the past month to mix a few of my band's songs. Macbook pro 2.33GHz. I also have a presonus firepod that I've been using to get audio into logic.

I would like to use Logic's IR utility to take an impulse of an acoustic guitar preamp that I own (d-tar mama bear) and then load that IR into another piece of hardware (fractal audio axe-fx).

Can someone help me out with the process of taking an IR using the utility in logic? I believe that the user IRs that can get loaded into the axe-fx need to be 1024 samples.

Since this is an outboard processor, I don't think I would need a poweramp or mic as if I were taking the IR of a guitar cabinet. Just 1/4" in and XLR or 1/4" out.

Thanks everyone.

Macbook Pro, Mac OS X (10.5)

Posted on Jan 19, 2009 9:41 AM

Reply

Answer 1

Jan 19, 2009 11:20 AM in response to gdgross

The IRU is a utility for making a sweep into an IR, ultimately for use in Space Designer. Getting the IR into something other than Space Designer will require some experimenting. The IRU actually generates a Space Designer preset based on the IR. You should be able to generate the IR and then edit it down to whatever size you need in any waveform editor. My experience is that the IRU process is better at capturing reverbs (time domain) than any outboard gear that adds distortion, like a preamp (harmonics, overtones and eq domain). Simulating that type of gear is a little more involved than just getting an impulse. It's still worth a shot though. Let me know how it goes.

Reply

Answer 2

gdgross Author

Level 1

11 points

Jan 19, 2009 4:04 PM in response to John Buehler

Thanks John. I'm going to give it a try and see how things come out. I was a little unsure of the process of getting the wav/IR out of logic, but it sounds like I'll have to do some experimenting to do that.

Thanks again,
geoff

Reply

Answer 3

Jan 19, 2009 6:35 PM in response to gdgross

I didn't mean that getting at the IR will take experimenting, I meant using it will. You can open and edit the SDIR file no problem in any editor. It seems to be an .aif.

Reply

Answer 4

gdgross Author

Level 1

11 points

Jan 19, 2009 7:36 PM in response to John Buehler

hehe, I guess I'm a total newbie then. I was able to get an IR just now using the utility, but I don't know where the .aif file is stored on my machine, nor how to convert it to .wav once I find it.

Maybe this is a basic question, but I'm new to both macs and digital audio stuff in general, so any help is greatly appreciated!

Thanks.

Reply

Answer 5

Jan 19, 2009 10:11 PM in response to gdgross

Well, it's probably in users/library/audio/impulse response folder. I assume you gave it a name, if it's not there use spotlight to find it.

I think it's totally lame that Logic won't open the SDIR file when everything else I have will (Sample Manager 3, Audiofinder, and Soundtrack Pro). So I guess you'll need some form of audio editor outside of logic to edit it and export it as a .wav.

Reply

Answer 6

gdgross Author

Level 1

11 points

Jan 20, 2009 8:10 AM in response to John Buehler

Oh, I found the SDIR file. I just assumed there was some other files associated with it hidden away in a folder somewhere, but maybe that's not the case. Sounds like I have to open the SDIR file in an external audio editor and then export a wav. Any recommended editor, since apparently logic itself won't work?

I did take a few IRs last night, and auditioned them in the utility with a pizeo-equipped guitar wav that I threw down. One sounded good, but the other was weird and boingy. The good sounding one looked like an IR I would expect to see: big peak and only a little data afterward. The weird one looked kind of funky when deconvolved - not like an IR I would expect. The weird one was also really long - like a second or so. As far as I know the only difference was in the levels, (and the settings on the preamp) so I don't really understand what was going on.

BTW, when I see red on the deconvolved waveform, does that mean my levels are too high? I don't think it peaked during the actual recording process.

Thanks for your help John, I really appreciate it!

Geoff

Reply

Answer 7

Jan 20, 2009 4:58 PM in response to gdgross

1) As far as an external editor goes, there is a lot out there and what you are trying to do is not that big of a deal as long as it sees the SDIR as an AIFC and opens it. I suggest anything that allows you to demo it first so you can see if it opens it. I've used Peak a lot, and it's fine. I bet there's some free ones out there that'll work. I am a fan of Sample Manager 3, and you could conceivably just use it to convert the SDIR to a .wav and edit it in Logic. SM3 is $90 I think.

2) Sometimes a buzz or a noise that was going on when you did the sweep can show up as a ringing or other anomaly. Always check your results before moving on.

3) I try and keep my peaks below -8 or so when I do the sweep, the IR can overload even though the sweep was not. Headroom is good. No need to sweep real hot.

Reply

Answer 8

Jan 20, 2009 5:05 PM in response to gdgross

1) As far as an external editor goes, there is a lot out there and what you are trying to do is not that big of a deal as long as it sees the SDIR as an AIFC and opens it. I suggest anything that allows you to demo it first so you can see if it opens it. I've used Peak a lot, and it's fine. I bet there's some free ones out there that'll work. I am a fan of Sample Manager 3, and you could conceivably just use it to convert the SDIR to a .wav and edit it in Logic. SM3 is $90 I think.

2) Sometimes a buzz or a noise that was going on when you did the sweep can show up as a ringing or other anomaly. Always check your results before moving on.

3) I try and keep my peaks below -8 or so when I do the sweep, the IR can overload even though the sweep was not. Headroom is good. No need to sweep real hot.

Reply

Answer 9

gdgross Author

Level 1

11 points

Jan 21, 2009 9:28 AM in response to John Buehler

Thanks again John.

I'll get my hands on an external editor and report back with my results!

Geoff

Reply

Answer 10

gdgross Author

Level 1

11 points

Jan 21, 2009 11:48 PM in response to gdgross

Well, I downloaded and tried a few utilities, none of which seemed to work, or else they couldn't export/save without buying the non-demo version.

As it turns out, however, all I needed was quicktime. 🙂 It'll open the .sdir and export a wav with no trouble at all.

The next step is for me to figure out how to convert the wav into a sys ex file that I can load into my axe-fx and audition, but that's a dilemma beyond the scope of this forum.

Thanks a bunch John; I will report back with the results of this little experiment. Hopefully it'll work great and I'll be able to carry one less thing in my travel rack.

Reply

Answer 11

Feb 8, 2009 3:26 PM in response to gdgross

Look around the Axe-FX forum at Fracta's web site.
There's a forum dedicated to Cabinets and IRs.
There's a utility called Axe-FX IR Converter that takes properly recorded .wav files of IRs and converts them to SysEx that the Axe can download as a User Cab.

<http://www.fractalaudio.com/forum/viewtopic.php?f=15&t=62>

Reply