Creating a Cabinet IR Using REW

[Ringleader]

Hello Everybody!

I am new to this forum and was brought here by the discovery of REW. It looks to be a very handy tool and I am excited to get familiar with all of its powerful features.

My application of REW may be different than many others but with the REW software I am hoping to create IR's of some of my favorite guitar cabinets that I own for "virtual" use in a high-end guitar processor.

So I guess I'll dive right in!

After I calibrate my system and take my measurement of a cabinet I receive a response curve. From there I am a bit confused what to do to convert it into an IR of my cabinet.

My main question (so far ) is:
If I export a .wav file of this response curve is that the actual IR of my cabinet or do I need to somehow deconvolve the IR from the response that I recorded? I guess I am not clear exactly what information is exported as a .wav file. If I need to deconvolve the IR, does anybody have experience doing this that could assist me? Thanks in advance for any help!

[brucek]

take my measurement of a cabinet I receive a response curve

No, the result of a measurement in REW is an impulse response. All other graphs are derived from that (including the frequency response graph).

Simply take a measure and click on the impulse response tab and your IR is there.

Export it as a wave file...... depends on the format in your 'high-end guitar processor' as to what you do with the wave file.

We do have a thread discussing convolvers here

brucek

[Ringleader]

Thank you for the reply brucek! So, just to be totally clear, nothing more is needed to create a cabinet IR than the procedure you described and then also a conversion to the proper sysex format that my guitar processor uses? In my researching I read the following response from a respected audio professional that led me to believe that I also needed to use a deconvolver.

The recording of the device's response to the sweep is not the impulse response of the device. It is the response of the speaker to a signal other than an impulse. Mathematically, it is the convolution of the speaker's impulse response with the signal you applied to the speaker. To get the IR, you must deconvolve the IR from the combined response (sweep convolved with device IR) that you recorded.

All of these steps are done automatically within the REW software?

[brucek]

to be totally clear, nothing more is needed to create a cabinet IR than the procedure you described and then also a conversion to the proper sysex format that my guitar processor uses?

Yes, as far as I know that's true. REW captures a sweep and FFT processing is carried out to derive the system's impulse response. You may then export that IR in the form of a wave file.

After that, I have no idea about your processor. Generally I believe people use the IR filters wav file to feed a DRC process that uses a convolver to create the filters, but this is different than what you're doing. You want to use the systems impulse response.

brucek