PreSonus Blog

There’s an old joke about guitarists:

“How many guitars does a guitar player need?”

“Just one more!”

…and sometimes I feel the same way about amp sims, because all of them are different. Ampire XT benefits from PreSonus’s “State Space” technology, and if you have no other amp sims, its collection of amps has pretty much all the essentials.

What’s more, you can load thrid-party cabinet impulse responses (IRs) that re-create the sound of various cabinets, mics, and mic positions. These go into the User Cabinet, whose unique feature compared to typical IR loaders is being able to load individual IRs for the three mics.

But you can take impulses even further by turning off an amp’s cabinet altogether, and following Ampire XT with the Open Air convolution processor.  Although most people probably think of Open Air as a way to create a variety of reverb and other space-based effects, it’s also a flexible impulse response loader that plays nice with cabinet impulses.

There are many free cabinet impulses on the web to get you started. Admittedly, the sound quality varies—some are fine, some aren’t, but there’s also a middle ground where tweaking the Open Air controls can give the sound you want. http://cabs.kalthallen.de is a popular source for free impulses (click on the Free tab), but there are many other companies that offer free samples, or sell impulses commercially.

The Setup

Create an FX Chain with Ampire XT followed by Open Air. The Impulse Responses are only for cabinets, so set up Ampire XT’s amp and effects however you want, but turn off the cabinet section (Fig. 1).

Figure 1: Click the cabinet bypass button (middle left, outlined in white) and the cabinet field will show None (upper right, outlined in white).

Follow Ampire XT with the Open Air, and start with its Default preset. Drag an impulse into the Open Air waveform display window (or click on the impulse name field to open the file selector, and then navigate to the impulse you want). Turn Mix to 100% so that you hear only the cabinet output, and none of the pre-cabinet amp sound (Fig. 2).

Figure 2: Make sure you set the Open Air Mix control to 100%, so that you don’t hear the pre-cabinet amp sound.

 Tweaking the Tone

The Kalthallen impulse shown in the screenshot above didn’t need tweaking to sound good, but you’ll find that with a lot of the free impulse responses, you’ll need to tweak the Gain and Frequency controls. Often the main problem is a “thin” sound and Fig. 3 shows some tweaks that help remedy this issue—pull back on the highs, and boost the low end for a bigger, beefier tone.

Figure 3: These EQ settings can help tame free impulse responses that sound too thin.

But the most dramatic tweaks come by enabling Shorten with Stretch and Stretch with Pitch, then varying the Length control. This can produce sounds that are similar to different mikings, or even cab sounds you’ve never heard before. The Predelay, ER/LR-Xover, and ER/LR controls can also affect the sound, although the differences aren’t as dramatic as stretching with the Length control.

Finally, although it’s great to have options, you don’t want to suffer from option overload (“maybe trying just one more impulse will give the sound I want…”). If you download a bunch of impulses, create a folder of favorites in a place where it’s easy to open it up, and drag-and-drop impulses into Open Air. If you find one you really like, save it as an Open Air preset for future use.