Only Two Cab Slots? No Problem!

ruso

Fractal Fanatic
I've seen a few people asking about this, so here's a tutorial I put together on how to Combine Impulse Responses using an FM3, a DAW, and Impulse Response Utility. There's a few reasons why you might want to do this. For example:
  • You want to run additional cabinets but the two available cab slots are already in-use.
  • You found a mix of cabinets you absolutely love, with the perfect balance and want to capture it into a single impulse response.
  • You want to free-up a little CPU (I save, on average, about 5% CPU by doing this).
This can be performed using your FM3, one of the various impulse response utilities available, and an audio editor. For this particular example, I will be using the following:

Fractal Audio Systems FM3
MacBook Air (running MacOS 12.1 Monterey)
Logic Pro 10.7.2
Impulse Response Utility (included with Logic Pro)

This tutorial assumes that you know your way around your FM3 and Logic Pro, but if you have any questions, please feel free to ask and I'll do my best to answer them. I will be editing this as I go, so please let me know if anything is unclear.

Step 1: Configure your FM3

In FM3-Edit, click on the "Setup" button. Select the "Audio/USB" tab, and change Input 1 Source to "USB (Channels 3/4)." Remember to change this back later.

FM3_Impulse_Response_Tutorial_01.jpg

Create a new preset with only a Cabinet Block. Alternatively, disable all blocks in your preset except the Input, Cabinet, and Output blocks. For this example, I have two impulse responses that have been balanced by reducing the level of Cabinet 1.

FM3_Impulse_Response_Tutorial_02.jpg


Step 2: Configure Impulse Response Utility

Impulse Response Utility is located at /Applications/Logic Pro/Contents/Helpers. Alternatively, use Spotlight Search to find it. Change Audio Input and Audio Output to “FM3.” Change Sweep Channel to Channel 3. Enable recording and change Input Channel to Channel 1. Set “Mode” to 10 seconds and “Reverb” to 1 second. Click "Sweep."

FM3_Impulse_Response_Tutorial_03.jpg

Watch your levels and ensure that the input is not clipping. If it is, enable recording, lower the Sweep Level, and repeat.

FM3_Impulse_Response_Tutorial_04.jpg

Once the sweep is finished and you are satisfied with the results, save your work.


Step 3: Deconvolve and Create Setting

Click "Deconvolve" to convert the capture to an Impulse Response.

FM3_Impulse_Response_Tutorial_05.jpg

Click "Create Setting."
FM3_Impulse_Response_Tutorial_06.jpg

When prompted, choose a name and click "Ok." The dialog box will inform you that an SDIR file was created. Make a note of the path shown in the dialog box.

FM3_Impulse_Response_Tutorial_07.jpg


Step 4: Locate and Rename Impulse Response

Navigate the above mentioned path and rename the extension of the file from "SDIR" to "WAV."

FM3_Impulse_Response_Tutorial_08.jpg
FM3_Impulse_Response_Tutorial_09.jpg

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Step 5: Import Impulse Response, Trim, and Export

Import WAV file into Logic Pro.

FM3_Impulse_Response_Tutorial_10.jpg

Trim the silence from the beginning of the waveform. FM3-Edit will take care of the silence at the end.

FM3_Impulse_Response_Tutorial_11.jpg
Export file.

FM3_Impulse_Response_Tutorial_12.jpg

Import file into FM3-Edit and Enjoy!

Comments? Questions?
 
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