HERE’S AN EASY WAY TO IMPROVE AN AMPsimulator’s tone dramatically: increase the samplerate at which it operates. Now, I’m not somegolden ears guy who insists that recordingsdone at 96kHz sound sooo much better thana CD’s standard 44.1kHz sample rate, but ampsims are a special case—especially at high-gainsettings.
The sample rate is the rate at which audiois converted to digital data. The faster the rate,the more accurate the conversion—just likehow videos that show more frames-per-secondgive smoother visual motion.
With most audiosources, 44.1kHz is an adequate sample rate.But overdriven/high-gain amp sims generateharmonics that can extend beyond the highestaudio frequency a digital system was designedto handle. This causes aliasing—a term for whathappens when the harmonics interact with thedigital system’s sample rate. The audible resultsare noise, atonal harmonics, and a blurred,often harsh sound. Raising the sample ratehelps minimize interaction with the harmonics.
First, set your audio interface to 88.2kHzor 96kHz (most current interfaces supportthese rates). Then, open an amp sim in standalonemode, and set its sample rate to matchyour interface (Fig. 1). You should hear muchsweeter high-gain sounds. This isn’t just dueto less aliasing. It’s also because the filters thatare an essential part of digital-audio conversiondon’t have to work as hard, and can soundmore natural.
You don’t get something for nothing,though. Higher sample rates stress your computermore, so you may have to increase thesystem latency to avoid audio dropouts. Fortunately,with today’s fast multi-processor systems,this is becoming less of an issue.When using an amp sim as a DAW plug-in,it may not be possible to run at higher samplerates with complex projects. For example, someother plug-ins might not work properly at96kHz, and the demands on your computermight be excessive.
One solution employed byIK Multimedia and Native Instruments is toinclude optional oversampling in their amp sims(Fig. 2). This runs the amp sim at a higherinternal sampling rate than the project itself,giving the benefits of a higher sample rate—even in projects running at 44.1kHz or 48kHz.Oversampling places more of a load on yourCPU, but far less than doubling the sample rateof an entire project.
If you can’t raise a project’ssample rate, check for places in amp sim programswhere you can enable oversampling—your ears will thank you, because the overallsound will be much more like a real amp.
Major props to Davide Barbi at IK Multimediaand Patrick Arp at Native Instruments for providinghelpful background material.
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