Is the 4×12 cabinet going to die out? We don’t think guitar players would ever allow it, but there’s a new kid on the block promising to keep our tube tone awesome even without a speaker or cab. It’s called full range flat response, and it could just be the best thing to happen to guitar amps in ages…

There was a time when guitarists went to great lengths to avoid hearing the sound of their cabinet piped through a stage monitor.

And for good reason: more often than not, the tone was harsh, cold and on the brittle side of glassy. It was a clear case of direct, in-your-face sound taken to an unpleasant extreme.

When your tone turns out to be as cringe-inducing as a dental drill burrowing into a root canal, drastic measures are in order, and some guitarists’ revulsion bore strange fruit indeed: it wasn’t unusual to see wedges’ high-frequency drivers masked with duct tape.

For many of us, a bad monitor signal was just another item on that long list of annoying inevitabilities that starts with death, taxes and spam.

A wedge monitor covered in duct tape, yesterday. Just one of the many, many reasons you should have rolls of this stuff in your gig bag at all times!

Even well-miked guitar cabinets sounded sorry over fullrange speakers, especially when your signal ventured into the distorted end of the spectrum.

Painting pictures with guitar tone

Although the rock gods seemed to cope well enough, the studio situation was even more frustrating for us mere mortals.

Inspiration is shy, elusive, and hard to capture when the cab is miked up in another room and you can only hear an alien version of yourself over stale-sounding studio monitors.

When guitarists paint musical pictures, taste, touch and tone are their tools of choice. Taking away that uplifting tone and ass-kicking attack is like forcing an old master to paint with a mop.

The reason we love guitar

Most of us who are drawn to this instrument find it so alluring precisely because those six strings can make such a soulful sound. Compelled to work with soulless, uninspiring tone, it takes a lot of discipline to nail a performance as inspired as some of our finer moments in the rehearsal room and on stage.

Fingers feel stiff, lines that usually flow effortlessly come out halting, and the anxious wait for the engineer to audition that last take against the backdrop of the mix is an excruciating exercise in patience.

Parallel but unequal signal chains and guitar sounds were an inauspicious pairing, and you couldn’t help but wonder how on earth one’s guitar heroes managed to sound so stellar on their albums. It was downright supernatural.

We recently achieved supernatural tube tones by miking up one of our TM212 cabs in a toilet. A girls’ toilet, no less. But there has to be an easier way… right?

And that element of mystery was a good thing, because what’s music without that inexplicable magic?

A Deluxe tube amp experience

In any event, things have changed with the arrival of modeling technology in the early noughties, especially when it comes to recording.

Many guitarists have a DAW (digital audio workstation) at home and, with nifty digital tools such as modelers and budget-friendly software solutions, you can come pretty close to capturing the guitar gods’ iconic tones.

Speaking of powerful tools, TubeMeister Deluxe certainly deserves more than passing mention. These rigs let you enjoy all the benefits of a tube amp on stage, at home or in the studio, even without actually connecting a speaker cabinet!

Is that even possible? Indeed it is.

This is the first breed of tube amp to treat users to a genuine FRFR experience, which comes courtesy of the groundbreaking Red Box AE (AE, by the way, stands for ambience emulation – more on that later!).

And FRFR means…?

OK, OK. I’d like to take the release of this game-changer as a welcome opportunity to elaborate on that cryptic abbreviation FRFR.

Short for ‘full range flat response’, the term FRFR is often bandied about when discussions in guitar circles turn to digital recording assets such as DAWs.

TubeMeister Deluxe 20 in a recording environment at H&K HQ in Germany. Not a cab in sight, as you’ll notice…

But what does it actually mean? Let’s back up a bit to scan the big picture.

Are the days of the speaker cabinet over?

These days, more and more guitar sounds are being generated in the studio and on stage without the benefit of the time-tested guitar-to-amp-to-cab-to-microphone signal chain.

Many artists have forsaken amps altogether.

Modelers and even laptops running amp software are encroaching on a domain once dominated by the classic amp head and cab + FX board combo. These tools’ signals generally go straight to a mixing console without ever seeing a guitar speaker cab in the signal chain.

Goodbye 4×12, goodbye back pain

So the very component that is such a formative force in shaping guitar tone has been taken out of the loop.

That may come as a bit of shock, given the almost cultic veneration accorded certain 4×12 cabs, but it works. Don’t believe us? This video we shot at The NAMM Show 2016 proves you don’t need a cab to sound good:

However, it only works well enough when the FRFR signal is treated with impulse response (IR) filters whip that signal into the shape of a typical guitar sound.

Put simply, FRFR capability is the means to render of an audio signal on a fullrange system such as studio monitors, ideally with linear frequency response.

What are IR filters, and how do they help me?

So, what to do IR filters do? Well, we’ve enjoyed a rather good run with our cabinet simulations.

The H&K engineers succeeded in emulating the sound of a miked guitar cabinet. They did this by first decoding the DNA of the guitar-speaker-cab-and-microphone-combo’s frequency response and then coming up with filter circuits that EQ the direct signal in such a way as to imprint it with this genetic stamp.

Imposing the frequency response on signals yielded quite convincing results, as the countless users who invested in the platinum selling Hughes & Kettner Red Box would attest.

Speakers and cabinets

There was a minor catch, though. The signal sounded much more like a miked loudspeaker in isolation, and less like a speaker in its natural habit; that is, installed in an enclosure.

Of course, we guitarists generally prefer well-dressed speakers in a fetching housing to the naked option because of the tasty flavoring that the housing adds to the tone.

And as we all know, the same speakers can sound very different in dissimilar housings.

What’s more, finessing the distance of the microphone to the speaker cone is a science unto itself. Classic speaker simulations largely ignored this variable.

Just like they did it in the old days (although maybe not always with as many mics as this!). But FRFR and the Red Box AE mean you no longer have to worry about stuff like this…

They factored the ‘hard’ parameters of the microphone and speaker into the equation, while neglecting the ‘soft’ stuff that comes down to good ears and lots of experience.

How IR filters make you sound more real

The answer to the question of what IR filters do is this: they factor those ‘ignored’ parameters – the natural sound of the cab, the distance between the microphone and speaker – into the sonic equation to inject a little more authenticity into the digital facsimile of a guitar cabinet’s acoustical behavior.

The point is, of course, to capture the cab’s sweet spot.

IR filters can even approximate the ambient sound of a room, which has a slight but tangible impact on the frequency response. After all, there’s a noticeable difference between the sound of your guitar cabinet in a tiled cellar and that same cab in a small studio cabin soundproofed with carpets and insulation materials.

An impulse response for every occasion

In principle, there can be as many IR variants as there are combinations of cabs, microphone placements and rooms. And if you’d rather not agonize over the many options, you can even create your own.

Yes, with just a few tools and a little patience, your personal cab setup can be distilled into a replicable data packet.

All this is great news for guitar players who are recording at home, but it’s also perfect for gigging players out on the road. We imagine our friend Christian Kreutzer (guitarist for German hip-hop king SIDO) is not really in a position to crank a 4×12 on the band’s tour bus!

IR + FRFR = your sound, any time, anywhere

But that’s just us thinking out loud. The key thing here is that IR filtering and FRFR capability have presented us with such a versatile solution that the days of the classic cabinet miking technique may well be numbered.

The benefits of this novel form of EQ certainly far outweigh any perceived drawbacks.

For one, the sound of your guitar as delivered by the PA no longer hinges on the skills, patience and whims of stressed technicians tasked with setting up your microphones.

With FRFR capability added to your guitar setup, your sound over a PA will be exactly the same as the sound you worked out at home, in the rehearsal room or in a studio. Really!

In the standard gigging scenario, where time is tight and the pressure is on, most techs/players won’t bother fiddling with various microphone placements to pinpoint a given cab’s sweet spot.

Seen in that light, IR-based FRFR technology is a dream come true for the gigging guitarist.

And once you have the sound of your dreams dialed in, it’s no less an advantage to have that tone at your fingertips, always and everywhere, at home, in the studio and in the rehearsal room.

How we got FRFR into a tube amp

Many modelers already have all this capability built into their engines and there are plug-ins available for home DAWs that deliver satisfying results.

However, FRFR capability was not to be had in any conventional tube amp head.

For one, you would have to tap the power amp signal directly because the power stage plays such a key part in shaping tone.

More TubeMeister Deluxe studio action. If you’re reading this and still wondering how much you can really benefit from the true FRFR tube experience, we sugggest you give the Deluxe amps a go when you next get the chance!

For the other, you’d definitely need a power soak to bring the signal down to a level suitable for processing without adversely affecting the power stage’s tone-shaping action.

The many benefits of Red Box AE

Add these features and subsequent IR filtering to a good amp, and you could conjure FRFR-enabled, all-tube-driven tone.

TubeMeister, for example, offers the exceedingly rare but certainly nifty combination of a tube-driven power amp with a very handy on-board power soak.

Then there’s this to consider: our experience with the Red Box has been so rewarding over the years that the idea of upgrading the TubeMeister Deluxe series with an IR filter practically suggested itself.

Our engineers dubbed this filter AE (Ambience Emulation, if this slipped your mind from last time!), and tweaked it to give the target device a ‘big picture’ view of the simulated source.

In other words, it delivers a realistic rendering of a true 4×12 in all its raging glory. And to top off what’s already a very good thing, Red Box AE even offers the novel option of bypassing the on-board filtering when you want to work with your own IR filters on your home DAW.

There are plenty of freeware plug-ins available to this end, so you can tune and tweak to your heart’s content.

Time to try out this new kid on the block…

TubeMeister Deluxe, with its practical on-board filters, sounds more than persuasive on a DAW. Watch this video we shot at NAMM 2016 for proof:

In fact, it sounds so very convincing that soon many home recordists may forgo a guitar speaker cabinet altogether.

Of course, it’s all a matter of taste, preference and habit.

However, if the day comes when the only difference between a speaker cabinet and the alternative is the former’s ability to set those trouser legs a-flappin’, then I believe you should seriously consider the benefits of FRFR, IR filters and Red Box AE.

Capturing great tone on stage and in the studio has never as easy and convenient as it is today.

What are your thoughts on the choice between FRFR and impulse responses or traditional speaker cabs? We’d love to hear your thoughts, so leave them in the comments section below…

First published: February 12 2016. Most recent update: December 22 2016.