Positive Grid BIAS X review – “it’s like having a virtual studio engineer doing the hard work”

$149, positivegrid.com

For the last few years Positive Grid has been busy redefining what we expect in terms of sound, usability and flexibility from our practice amps in the shape of the wildly popular Spark family of products.

However, before PG became the world’s foremost purveyor of tiny amps, there was BIAS – a powerful, great-sounding and hugely popular amp and effects plugin. BIAS has percolated away in the background for the last few years, getting regular updates and building a reputation as one of the best sounding and most user-friendly guitar plugins around. Now though, things are really getting interesting with the launch of BIAS X – a brand new platform that’s brings a lot more ahem, intelligence, to the party.

Positive Grid BIAS X – what is it?

BIAS X is an in-the-box (that’s on your computer, by the way) amp and effects suite – with a twist. Billing itself as the first AI-powered ‘tone creation platform’, BIAS X provides you with 30+ amps, 60+ effects, a whole bunch of cabs and the ability to combine those in any manner you desire. The twist is that you don’t have to do the tweaking – thanks to the AI Assistant built into BIAS X’s user interface, you can simply tell the AI what sort of sound you’re looking for (or even upload a snippet of a tone you want to emulate) and quick as a flash it’ll create a plugin catered to your requirements.

The idealised version of all this effectively casts you as a megalomaniacal 80s rock star at the height of their money-no-object studio excess. The concerns of regular guitarists who have to set up their own gear or tweak their setups to get the sound they’re after are, frankly beneath you – you have underlings for that.

In this scenario, the BIAS X AI Assistant effectively playing the role of an eager to please virtual studio engineer sat beside you doing all the hard work and catering to your every whim no matter how unreasonable. Except the AI doesn’t require constant cups of tea to keep functioning, and is unlikely to demand a writing credit on the album because they came up with a maraca part that’s buried so deep in the mix you’d need Jacques Cousteau to find it.

Taken at face value, that all sounds rather appealing doesn’t it? Especially if, like me, you’re someone for whom the world of in-the-box recording is approached with a mixture of reticence and outright disdain precisely because you find the thought of spending half an hour constructing a signal chain using a mouse and keyboard a special kind of torture.

Getting a LLM to do the lion’s share of the work for you seems like one of those ‘actually worthwhile applications of AI’ that I’ve been hearing about but seeing precious little evidence for. Let’s find out if it lives up to that expectation…

Positive Grid BIAS X – who is it for?

Now, before we get into the testing part of all this, it’s probably worth having a quick sidebar here for existing BIAS users. If you’re expecting BIAS X to be BIAS FX 2 with a shiny AI helper in there, you’re going to be disappointed – at least at launch.

Because some of the important stuff that you might be expecting just isn’t there in BIAS X. For starters you get barely a third of the number of amps and effects as you do in BIAS FX, and you also won’t find the nerdy component-level tweakery that made it such a popular platform for guitar players.

Instead, this feels more like a bridge between the casual nature of the hugely popular Spark platform and its companion app, and the more involved world of ITB guitar playing – it’s probably not a coincidence that Spark also has 33 onboard amps, for example.

That doesn’t mean that BIAS is underpowered or lacking in features and usability, however – it’s every bit a modern high-end amp and effects plugin, just one that’s a little more streamlined with its sounds out of the gate.

That means you can still create the most long and unwieldy chain of effects your processor can handle – complete with dual amp and cabs if you so desire. I finally got bored having created a chain of over 40 amps and effects, with my M2 MacBook Pro’s chip still only showing 43% use (this handy DSP readout in the top right corner will come in handy if you’re using a less powerful machine however). You can also upload your own IRs in place of the inbuilt cab options, and of course adjust the mic placement accordingly.

Positive Grid BIAS X – in use

Now, as mentioned up top, I am one of those people for whom the whole amp and effects software thing has been firmly placed in the ‘not for me’ category. Despite being a very techy person generally, when it comes to guitar I prefer things to be as simple and analogue as possible. That said, I have in recent years had my head turned by the simplicity and usability of Positive Grid’s Spark products in a practice scenario… maybe BIAS X can turn my head similarly?

I might be somewhat ITB-sceptic, but I’ve used enough amp and effects plugins in my time to know that it’s useful to have a basic play around to get a clean tone you’re happy with before taking the leap into the agentic unknown. If nothing else, this is about setting your input levels and other boring stuff to give the fancy stuff a better chance to work – and so I quickly jack into BIAS X’s interpretation of a Deluxe Reverb and make sure my levels are where they need to be and everything sounds good.

This is one thing to very much be aware of in all this before we get the AI involved – the software can only create something it thinks will work, but a big part of actually sounding good is what you’re plugging into it. While I did experiment with trying to cajole the AI into creating presets specifically for guitar types, I didn’t have a huge amount of joy here – expect to have to refine your EQ to your specific guitar and its pickups.

There are a bunch of factory presets in BIAS X that offer the full gamut of tones from crystal cleans to the heaviest chugs – but that’s not why we’re here is it? Let’s click that little diamond-shaped button on the bottom left of the interface and get chatting.

There are two ways to interact with the assistant – either you can put in a text prompt and let the AI make its own mind up, or you can drag and drop an audio file and it’ll do its best to match the tone onboard.

We’ll start with the text-to-tone option, and out of the gate it’s worth noting that, if you’ve had any previous experience trying to get something useful out of an LLM, you’ll know that it helps to be quite specific in the way you prompt it.

While the Assistant’s Quick Tips encourage you to ‘describe a mood, idea or favourite artist’ to get a sound you want, I quickly realised that it helps to add as much detail as possible. “Give me an Oasis tone” is going to provide a much more complex set of variables for the AI to work with than if you ask it to, “Give me a guitar tone similar to Oasis’s Supersonic – the saturated distorted tone of a cranked amp with lots of bottom-end and slight slapback delay”.

In truth the AI does a pretty decent job even with more basic prompts, but you’ll have to accept a certain degree of refinement is necessary here. Thankfully, the Assistant is more than happy to help make minor tweaks and broadly does a nice job of it – ask it to ease back the gain or take some of the top-end out of a sound and it’ll quickly present you with an updated preset to try out.

One slightly weird eccentricity I noticed in this regard was its predilection for chucking an EQ pedal into the chain willy nilly. If you ask it to roll off some of the top end or boost the mids, it will usually respond by chucking a six-band graphic EQ into the chain, when all that really needed to happen was a roll off of the tone stack on the amp. Quite often this also sounds bad, and is easily remedied by being more specific with the prompt, but it’s a good reminder that as with any AI agent, you are not in fact talking to a living breathing virtual tea boy, and expecting it to show initiative or common sense is not always a guarantee.

Where it was more impressive was when things get weirder – asking it to craft Jack White’s glitchy octave-overloaded Blue Orchid guitar tone yielded a very solid result out of the gate and with a couple of gentle prompts I was working with a much more usable and convincing recreation than I’ve ever managed with a bunch of fuzz and pitch-shifting pedals myself.

It should also be noted that these amps and effects sound exceptionally good across the board. Positive Grid boasts about the component-level circuit modeling that goes into their sounds, and while you may not be able to tweak them to taste here, the results are still remarkably faithful to the originals. Too often ITB amp and effects plugins are judged purely on their heavy tones,but I was pleasantly surprised with the crunchy lower-gain offerings here – they sounded rich and authentic. With that in mind, it was quite frustrating that the Assistant consistently seemed to default to higher gain options than I had specified, occasionally choosing woefully inappropriate amps or pedals in the service of more distortion that I had never really asked for – a system is only as good as the data it’s trained on I suppose, and the bulk of BIAS users are going to be leaning more towards heavy tones.

Positive Grid BIAS X – should you buy it?

There are of course other issues to consider when you insert the word ‘AI’ into any product – both environmental and ethical. It’s very hard to quantify how much BIAS X is contributing to Generative AI’s boiling of the planet – though I’d wager it’s a drop in the literal oceans compared to all those chronically unfunny ‘me as an action figure’ posts that were everywhere a few months back.

Less clear-cut is the issue of exactly how BIAS X has become quite so clever at building guitar tones. Positive Grid says that in addition to “component-level circuit modeling” of the amps and effects the AI Assistant was trained using over 1 million “guitar tones spanning eras, genres, and techniques.” Now, the question you may well be asking is where exactly did that massive data set come from? I posed this question to PG, who told me that while they will use anonymised user data from BIAS X to continue to train the Assistant to improve it over time, they were unable to provide any concrete information as to where the original dataset was compiled from.

It’s an unsatisfactory answer, to be honest – especially when there is huge controversy across the world right now over what is acceptable data to use to train a generative AI product on, and what isn’t. But ultimately, the importance of these issues is very much in the eye of the beholder. It will be absolutely critical to some, and utterly inconsequential to others – with many sat in the middle mainly concerned with whether it works or not.

And work it absolutely does. Granted, if you’re already a whiz at crafting your own presets, tweaking things at the granular level and knowing exactly what you need to get to the sound in your head, the utility of the AI Assistant is somewhat limited, handy as it undoubtedly is.

But I don’t really think that’s who BIAS X is for – in many ways it feels like a way to graduate people from one of the Spark amps into a more professional and advanced world, without the massive difficulty spike that usually comes with it.

With a really simple and easy to use interface, great tones across the board and a good spread of all the classic amps and effects you might need, BIAS X is the perfect amp and effects sim for people who don’t want to make it their entire personality.

In my time with BIAS X, I genuinely found myself having fun with a guitar plugin in ways that I never had before, and that’s all down to the power and usefulness of the Assistant. It’s a shame there’s not a demo version or a free trial really – while BIAS X looks good on paper, it’s only really in practice that you appreciate its game-changing potential. The more people they can get trying it, the more impactful it’s likely to be.

Positive Grid BIAS X – alternatives

The most famous name in the guitar plugin scene is IK Multimedia’s AmpliTube 5 – it was one of the very first bespoke amp and effects platforms and has evolved and grown over the last decade or so to become a hugely varied and good sounding product. It’s starting to show its age in terms of usability now however. If you want quality and huge choice in one package, it’s hard to look past Line 6’s Helix Native – if you can think of it in terms of amps, effects and such, it’s in there. Another simple to use and well-stocked option that’s perhaps a little on the elderly side now is Native Instruments Guitar Rig 7.