I felt that my earlier post might not have done a good enough job explaining why I am so enamored of this software. After all, a glowing review can be pretty empty if it isn’t clear why the product makes the reviewer glow. In the spirit of explication and service to my readers, here’s a (somewhat, but not too technical) explanation of guitar feedback, and why you might want Softube’s Acoustic Feedback plugin.
Feedback in the context of a physical guitar amp is the product of a lot of things. It is a somewhat controllable feedback loop that involves your guitar’s body, your guitar’s strings, your guitar’s pickups and their resonant frequencies and frequency response, your amplifier’s gain, frequency response, and power output, your cabinet’s ability to move air, and just as importantly the physics of the room you’re playing in. The physics of sound are such that there will be spots where you can’t get any feedback no matter how cranked your amp is (nodes), and there will be spots where feedback seems very easy and your guitar just screams (anti-nodes). Guitar amp and cab systems are great for making controllable feedback because they’re made to operate at high output levels and hence they move a lot of air. It’s what they’re supposed to do. In fact, modern amp modeling software usually has no problem with feedback if you’re running into a power amp and a speaker cabinet! There’s nothing lacking in the technology of, for example, Amplitube Metal – if the supporting hardware and the physics are on your side, it’ll let you scream and squeal just like the real amps it models. Ditto for others.
So why is a plugin like Acoustic Feedback necessary? After all, if the software can do it, that’s all that matters, right? You wouldn’t want to put something that makes more feedback in front of a real amp, would you? (well, sure, lots of people would, dirt pedals, compressors, you name it – but that’s beside the point Very Happy)
There are a few factors that make musically useful, controllable feedback a tougher prospect for amp modeling setups in the studio. First, there’s a world of difference between a guitar amp made to run hot and ready and a speaker cab made to pump out massive volume and take a pounding without giving up the ghost, and a set of studio monitors. Studio monitors are usually capable of relatively high output – my KRK VXT 6, for example, claim that they can reach peaks in excess of 109dB – but they are very uncomfortable when asked to do so. Frankly they tend to sound like garbage when operated near their peak output. Professionals like Bob Katz will tell you that ideal monitoring volume is no higher than the mid 80dBs, both because that is the level at which we can safely and comfortably listen for hours a day without suffering hearing damage, and because our hearing curve is as close as our imperfect ears get to flat at ~83dB. So, there’s a real difference in the intent and design of monitors compared to guitar power amps and cabinets that results in a basic discomfort with moving that much air for that long of a time, especially under feedback conditions (which can cause unsafe peaks for monitors).
But let’s say you’ve got a set of Barefoots and as the last son of Krypton the idea of ear strain is something you scoff at. Even if your monitors can take the punishment and put out the sound no problem, you still might have no luck getting musical, controllable feedback. That’s because it’s entirely possible that the physics of your recording environment are not such that you have a conveniently located anti-node; wail all you like, but if the physics aren’t on your side, you’ll get nothing more than ordinary sustain.
I monitor at about 83dB, and try as I might only the higher gain amp models in my substantial collection will give me any kind of feedback. It seems that I’ve got that unfortunate physics problem. However, Softube has solved it for me. The clips in the first Softube Acoustic Feedback article are recorded at my usual spot, with that low monitoring volume, and yet there it is, musical sustain that I can control and use. And the same goes for the Preampus Classic Head series clips – the feedback you hear is the result of Softube’s Acoustic Feedback plugin combined with the virtual amps’ effect on the sound. Of course it doesn’t do it all on its own, it relies on having a realistic amplifier model after it in order to get such a realistic sound!
Softube Acoustic Feedback is the solution to a problem that perhaps not everyone will have – count yourself lucky if you don’t, if through accident or intention your studio accommodates your modelers’ capabilities fully – but for those of us who do have it, and who admire the musical use of feedback (artists such as Hendrix, Van Halen, Satriani, Vai, and many more have been fond of playing with feedback as a big part of their sound), this plugin definitely makes a $99 difference and more.