More on Softube’s Acoustic Feedback: An Explanation of Feedback, and Why You Might Need This Plugin

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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.


8 Responses to More on Softube’s Acoustic Feedback: An Explanation of Feedback, and Why You Might Need This Plugin

  1. blaknoize says:

    Pity its not a free, I find my virtual rig is getting full of free plugins these days!

    I havent read the earlier post but I guess you need a dongle to try out the demo?

  2. geareview says:

    Yeah, it would be nice if all the cool plugins in the world were freebies, wouldn’t it? Luckily there are a ton of great sounding freeware plugs but the commercial entities are making great software, too, and a lot of the time you can’t get stuff like what they make for free. Being well funded they have resources to put toward dedicated research and development teams, and when it comes to modeling they can get their hands on real gear to test and dissect for greater authenticity while many freeware makers are limited to modeling based on schematics, which are A) idealizations that may not reflect real-world differences in the units, and B) often not available nor necessarily accurate.

    Hence why some freeware guys like Ken don’t do modeling of traditional amps and instead focus on making the computer a new medium for guitar in its own right, without worrying about trying to make it fit the standards of the physical world. But there are also freeware makers like Nick Crow, LePou, and BTE Audio (and others) who still manage to make amazingly high quality simulations with the data that’s available with some digging on real amps and gear.

    I honestly think that even if this was the only software I needed my iLok for, I would have an iLok just to use this, though. It’s that good, for me. I don’t usually just gush and fawn but this plugin kicks ass.

  3. blaknoize says:

    Im looking forward to what you can get out of Metal Amp Room and the Vintage Amp Room, I have heard Vintage Amp room and the White Amp can get some pretty good power amp type distortion, the thing I didnt like was there was no way of disabling the cab sim…

  4. blacknoize says:

    Have a go on the feedback last night, I must say it sometimes get it just right, other times it seems to go a bit wild if you leave it too long, It does the foxy lady into perfect! Have to be a bit more careful as you go more high gain…

  5. geareview says:

    My go-to settings for it are:

    Mix no higher than 9 o’clock

    Feedback from the middle of Natural (for crunchy stuff) to the upper part where it meets Wild (for anything where more quickly rising feedback is appropriate)

    Threshold on Moderate. That’s really important, higher Threshold values than appropriate for the guitar you’re using are what makes it sort of get out of bounds and go into “tone generator” territory.

    See if any of that helps… It takes some getting used to, but with practice you can play with the feedback just like you would with a really feedbacking guitar amp.

  6. blacknoize says:

    Seems weird putting a setting that low dont know why because thats where it what I have Breverb set to on the mix as well, feels like you need to turn it up when its a knob, I had it at around 12, thats why it was misbehaving šŸ™‚


  7. geareview says:

    I can think of two reasons why Softube would want to have higher settings available than what are musically useful for guitar feedback:

    1.) Adjustments will be necessary to tune it for different circumstances. For example, pickups with lower output or a darker frequency response will need different settings than hot, bright pickups or actives; and an amp without a lot of gain going on isn’t going to sound right if it’s screaming feed-back like a 5150 would! Plus they don’t know if you’ll be using the plugin with their amp modelers or with someone else’s product, and every software has its own things going on – who knows how product X will react to the same setting that works great for product Y?

    2.) It doesn’t cost them any extra to have a nice wide range of adjustment and allow the user access to the software’s most extreme potential, and it adds value to the software for usage in other applications, e.g. as a tone-generator/oscillator when used with other sources than guitar.

    There’s probably more to it besides those reasons, but they make sense to me.

  8. blacknoize says:

    I just meant I like to turn knobs up high!

    I guess its the Hendrix Syndrome šŸ™‚

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