
Compared to traditional speaker simulators, IRs offer much greater realism and depth.
I find the evolution of rock guitar tone to be a fascinating subject. A ā59 Fender Bassman cranked up through its internal 4x10ā speaker configuration sounds nothing like a Mesa Dual Rectifier through its oversized, closed-back 4x12ā cabinet with Celestion Vintage 30s. And the speakers and speaker cabinet are a huge part of the equationāif you were to run the Mesa Recto into the Bassman speakers, youād get a completely different tone, but one that leans in the classic Bassman direction.
The same thing goes for Vox tonesātry running almost any amp into an open back 2x12ā with Celestion Blues and youāll instantly see just how much of that classic Vox character is actually coming from the cabinet.
Itās not always easy to do this kind of research. A lot of these differences become more apparent at volume, and cranking tube amps is just not an option for many guitarists. Assembling a large speaker cabinet collection is even more impractical. But because of these factors, guitarists have long been using speaker simulation devices to simulate the characteristic sound of different cabinets. Devices such as the Palmer PDI-09 apply a filter or EQ curve that mimics the sound of a guitar speaker to the full range output coming off your amp speaker out. This processed signal can then be sent to a PA or recording setup. Devices like this can work well, but you are usually stuck with one or two preset EQ curves, and the filter doesnāt replicate many of the complex factors that come into play when micāing a speakerāthe thump of the cabinet, the airiness, or early reflections.
Recently, a whole new technology has surfaced called Impulse Responses (IRs). The first time I encountered Impulse Responses was in reading about Altiverb, the popular convolution reverb plug in. In lay terms, Altiverb gives you the power to sample any acoustic space you can think of, load it as an IR into the plug in, and voila, you have the characteristic reverb of say, the Sydney Opera House available to you in your DAW. But IRs are not just used for reverbs. You can effectively capture the sonic fingerprint of just about anything you can pass a sound through using IR technologyālike a micād speaker cabinet.
Compared to traditional speaker simulators, I find that IRs offer much greater realism and depth. When you apply an IR to a line out signal from your amp, you are not just applying a preset EQ curve to your ampās signal, you are essentially applying the distinct sonic characteristics of a certain speaker, cabinet, mic, mic preamp, and any early reflections that also make it into the mic during the recording process. There are libraries of IRs available to you at your fingertips, an almost endless variety of cabinet and micāing combinations. You can mix and match and blend virtual cabinets to your heartās content. And when you land on a sound you really like, itās easy to store that sound within your DAW, so you can call it up again later.
Of course, you canāt just plug a line out from your tube amp into your recording console or computer interface. Tube amps need to see a load (either a speaker or a dummy load of some sort). And youāll need a good DAW and a convolution plug in that allows you to load IRs as well. To help us get a handle on what IRs mean for us guitarists, and how we can use them both live and in the studio, Iāve asked Mike Grabinski from Red Wirez Impulse Responses a number of questions.
Thanks for being a part of this, Mike! First off, what is an impulse Response, and how can guitarists incorporate them into their rigs?
Technically, an Impulse Response, or IR for short, refers to a system's output when presented with a very short input signal called an impulse. Basically, you can send any device or chain of devices a specially crafted audio signal and the system will spit out a digital picture of its linear characteristics. For speaker cabs, that means frequency and phase response, phase cancellation between multiple speakers, edge reflections, and other audible signatures wrapped up in the gnarly, old pieces of wood, paper, and glue that guitarists find so endearing. IRs will not capture non-linear stuff like distortion and compression.
When you're capturing an IR from a speaker cab, by necessity you are also sampling your D/A converter, power amp, the mic, mic preamp, your A/D converter, the cables you're using, and the room you are in. Basically, everything that comes in contact with the impulse as it makes it round-trip from your DAW and back again. So, it's important to use high quality gear and have a good recording environment. There's really no cheating physics.
Once you've captured a speaker cabinet IR, you process the signal coming from your amp by convolving it with the IR, imprinting the signal with the sound of your speaker cabinet. There are quite a few plug-ins and a few devices these days that will do the convolution part.
What are the benefits of using impulse Responses versus traditional micāing of speaker cabinets? IRs give you access to gear and acoustic spaces that might be too expensive or otherwise unattainable. The ability to run totally silent can be a real plus, too. Especially when cranking even a 30-watt amp can make your ears bleed, your dog run for the hills, or make your neighbors call the SWAT team.
IRs are a boon in a live situation, as well. Because you are essentially going straight from your rig into the house system, a setup using IRs is mostly immune to bleed and feedback from other instruments. You have more control over your tone. You are no longer at the mercy of the overworked sound guy, who would probably love to spend 10 minutes finding just the right mic position, but just doesn't have the time. And because you are eliminating a lot of the variables from the process, you can more easily reproduce your tone from venue to venue.
In your opinion, how close does an impulse response come to replicating the tone and overall coloration that that the typical cabinet/mic/mic preamp chain creates?
Early on I did double blind tests to convince myself it was worth the effort and expense to sample all these cabs. When levels are matched and you are comparing an IR and a mic in exactly the same position it is very hard to hear any difference at all. With dynamic mics, at least, I can sometimes pick out the IR, because a mic like the SM57 exhibits some distortion and I know what to listen for, and more importantly I actually know one of them is a real mic and one is an IR. With condenser mics, which are generally more linear, they sound pretty much identical. If you gave someone a recording and didn't tell them you were using IRs, they would never know, or even think to ask.
What's the best way to get your guitar amp signal into an Impulse Response that's loaded up in a typical computer host?Well, if making noise is an option, the best way, in my opinion, is to tap your amp's speaker out with a DI that can handle the power and then pass the signal through to a real speaker. That way, you are capturing preamp and power tube distortion and your amp still gets a reactive load. You don't really care what the speaker sounds like because you are going to be using IRs for the tone. You can shove it in a closet in the basement and as long as it can move some air, it's shouldn't negatively impact the DI signal. Some amps have the DI function built into the amp. Some even tap the signal coming from the power tubes, so a separate DI is not always necessary.
If you have to run silent, then you need a dummy load to take the place of the speaker, otherwise you can damage your amp's output transformer. There are lots of attenuators that also function as dummy loads out there. It is important to understand that your tube amp will probably react differently to a dummy load and you may find that your tone is missing the low-end bump and upper-mid rise you are accustomed to when using a speaker.
There can be several reasons for this, but one major factor is that speakers do not present a uniform load to your amp. If you look at a typical guitar speaker's impedance curve, which is a plot of the speaker's impedance across the frequency spectrum, you will see a big low-end bump and a steady upper-mid rise. This can also be described as a midrange scoop, depending on your perspective.
The load, or impedance, measured in ohms, will differ based on the frequency of the your amp's output. Solid-state amps have low output impedance, so their power output is not jerked around very much by the speaker's varying load. Tube amps have relatively high output impedance and as a result they deliver more power as the impedance of the speaker rises. And for a typical guitar speaker, that means you hear more bass and upper-mids.
Because a lot of dummy loads and attenuators present a uniform load to the amp, your amp's output will remain constant across the frequency spectrum. If you're accustomed to a low-end bump and upper-mid rise, you will probably hear this as the dreaded attenuator tone suck. To alleviate tone suck, you can use EQ. An alternative would be to use the sampled impedance curve of a real speaker to adjust the highs and lows in an authentic way.
What equipment does a musician need in order to use Impulse Responses with amplifiers, both live and in the recording studio?
You need a load for your amp, either a speaker or dummy load and a DI capable of tapping the speaker out of your amp. You also need a means to convolve the IR with your amps' output. In the studio, you can use a convolution plug-in. There are quite a few, including our own mixIR2 (wink, wink, nudge, nudge).
Live, the options are fewer and generally more expensive because you need a reliable device with enough horsepower to do the convolution with minimal latency. Not an easy task on a stage.
Letās look at that for a minute. It's relatively easy to load an IR into a host on a computer in the studio, but what about boxes that allow you to do this easily live, in a road-worthy portable package? Say, with a built in load for your amp, and with multiple memory locations for IRs so you can load them up and take them to the gig? What's out there now, and do you see a market for more boxes like this down the road?
There aren't too many that I know of. There's the Fractal Audio Axe-Fx and Axe-Fx II, the Torpedo VB-101, and apparently you can load IRs into the Digitech GSP 1101 with some unofficial firmware mods. It is my understanding that the GSP 1101 truncates the IRs to 128 samples, which would limit your low and low-mid resolution. I suppose you could rig up a laptop, but I'm not sure how reliable and road-worthy that would be.
There seems to be increasing interest in these kinds of devices, so I'm sure more will pop up in the future.
Right. Also, we should mention, the Axe-FX and the GSP 1101 wonāt provide a load for a tube amp but they do work great as hosts for IRs. I use the Axe FX this way live. Anything else you'd like to share?
San Dimas High School Football rules!
[Updated 12/12/21]
- The Recording Guitarist: Impulse ControlāMastering Fake Spaces ... āŗ
- The Recording Guitarist: Speakers? We Don't Need No Stinking ... āŗ
- Amp Mic'ing vs. Impulse Responses - Premier Guitar āŗ
For the first time ever, two guitar greats, John 5 and Richie Kotzen will be heading out on the road this year. The tour will launch October 16 and run through November, hitting markets across the U.S.
Find the full tour itinerary right plus a link for tickets & VIP, including additional dates featuring John 5 only. Reserved seating tickets will go on sale Friday May 16 though a fan presale will begin today at noon local time and fans are strongly encouraged to buy early to get the best seats.
Meet and Greets for both artists will be available. For John 5 please go to: https://john5store.com/collections/vip.
Today, John 5 also announces more details of his anticipated new album. Called The Ghost, it will be released October 10 and is led by the new track āFiend,ā featuring Kenny Aronoff.
John 5 continues running public tours this month for his Knights In Satanās Service Museum of KISS Memorabilia in Los Angeles, California. Guided tours are open to the public for one month only (with a possible expansion). Current dates available are May 12-16, May 19-23 and May 27-30. Each will be led by John 5 himself who will provide tons of rich detail and answer any questions. Secure your place HERE.
JOHN 5 continues to tour with Mötley Crüe including an upcoming residency in Las Vegas in 2025.RICHIE KOTZEN &
JOHN 5 FALL 2025 TOUR
October 16 El Cajon, CA @ Magnolia
October 17 Riverside, CA @ Fox Performing Arts
October 18 Roseville, CA @ Goldfield Trading Post
October 19 San Jose, CA @ The Ritz
October 21 Phoenix, AZ @ Celebrity Theatre
October 22 Albuquerque, NM @ KiMo Theatre
October 24 Dallas, TX @ Granada Theater
October 25 Leander, TX @ The Haute Spot
October 27 New Orleans, LA @ House of Blues
October 28 Memphis, TN @ Minglewood Hall
October 29 Nashville, TN @ Fogg Street Lawn Club
October 30 Atlanta, GA @ Variety Playhouse
October 31 Orlando, FL @ House of Blues
November 1 Fort Lauderdale, FL @ Culture Room
November 2 Clearwater, FL @ Capitol Theatre
November 4 Richmond, VA @ The National
November 5 Leesburg, VA @ Tally Ho Theater
November 6 Patchogue, NY @ Patchogue Theatre
November 11 Glenside, PA @ Keswick Theatre
November 12 Derry, NH @ Tupelo Music Hall
November 13 Foxborough, MA @ Six String Grill & Stage
November 14 Stroudsburg, PA @ Sherman Theater
November 15 Lorain, OH @ Lorain Palace Theatre
November 16 Columbus, OH @ The King Of Clubs
November 17 Warrendale, PA @ Jergels
November 19 Wyandotte, MI @ District 142
November 20 Flint, MI @ The Machine Shop
November 21 Fort Wayne, IN @ Piereās
November 22 St. Charles, IL @ Arcada Theatre
November 23 Belvidere, IL @ Apollo Theatre
November 25 Denver, CO @ Oriental Theater
November 29 Pioneertown, CA @ Pappy & Harriet's*
*John 5 only
PRS Guitars celebrates 40 years with the limited edition McCarty SC56. Featuring vintage-inspired design and modern innovations, this single-cutaway guitar pays tribute to Ted McCarty and his impact on the industry. With only 400 pieces available, this instrument is a must-have for collectors and performers alike.
PRS Guitars today announced the 40th Anniversary McCarty SC56 Limited Edition. With a classic PRS single-cutaway body shape and carefully chosen specifications, the McCarty SC56 is both a tribute to tradition and a reliable tool for the modern performer. Only 400 pieces will be made.
āThe SC56, signifying Singlecut and 1956, model is our most recent tribute to my late mentor Ted McCarty and his impact on the guitar industry. We started with our take on a classic late ā50s singlecut body. 1956 marks the year that Ted first had guitars made with his newly coined 'humbucker' pickups. It also happens to be the year I was born. Bringing vintage design into the modern era, we loaded this model with our McCarty III pickups, meticulously designed to deliver warm, clear, vintage tone with exceptional note separation and dynamics,ā said PRS Guitars Founder & Managing General Partner, Paul Reed Smith.
Anchored by a maple top and mahogany back, the 24.594ā scale length and 22-fret Pattern Vintage neck work with Phase III non-locking tuners and PRS two-piece bridge to promote its musical sustain. The PRS McCarty III pickups are controlled by a simple layout ā two volume controls, two tone controls, and a three-way toggle on the upper bout.
Single-cutaway guitars are known to be heavier than their double-cutaway counterparts. The McCarty SC56 Limited Edition design incorporates weight-relief, decreasing the weight of the guitar by about 2/3 of a pound, while maintaining several points of attachment between the guitar top and back to eliminate the āhollowā sound of the cavities and promote tone transfer.
With appointments like binding on the fretboard, classic bird inlays, and a vintage-inspired nitrocellulose finish, the 40th Anniversary McCarty SC56 Limited Edition blends heritage and innovation into a timeless instrument.
PRS Guitars continues its schedule of launching new products each month in 2025.
For more information, please visit prsguitars.com.
40th Anniversary McCarty SC56 Limited Edition | Demo | PRS Guitars - YouTube
The Future Impact V4 is an incredibly versatile pedal with an exceptional range of sounds. In addition to producing synthesizer sounds such as basses, leads and pads, it can function as an octaver, chorus, flanger, phaser, distortion, envelope filter, traditional wah-wah, tremolo, reverb, etc., and even has a built-in tuner. It can potentially replace an entire pedalboard of dedicated single-effect pedals.
The very powerful signal processor of the Future Impact V4 is able to replicate the various oscillator, filter, amplifier and envelope generator blocks found in classic synthesizers. In addition, it contains signal processing blocks more traditionally used for processing the sound of an instrument such as a harmonizer block and audio effects such as chorus, distortion and EQ. These architectures complement each other in a very flexible way.
Setting the standard for the bass guitar synth pedals since 2015, together with an enthusiastic community and long line of great artists, the Future Impact V4 is the guitar synth platform for the next decade.
Belltone Guitars has partnered Brickhouse Toneworks to create a one-of-a-kind, truly noiseless Strat/Tele-tone pickup in a standard FilterāTron size format: the Single-Bell pickup.
The Single-Bell by Brickhouse Toneworks delivers bonafide single-coil Strat and Tele tones with the power of a P-90 and no 60-cycle hum. Unlike typical stacked hum-cancelling designs, Brickhouse Toneworks uses a proprietary āsidewindā approach that cancels the 60-cycle hum without sacrificing any of the dynamics or top-end sparkle of a Fender-style single coil.
Get the best of both worlds with clear bell-like tones on the neck pickup, signature quack when combining the neck and bridge pickups, and pristine twang in the bridge position backed with the fullness and power of a P-90. Push these into overdrive and experience the hallmark blues tone with plenty of grit and harmonic sustain ā all with completely noiseless performance.
Key Features of the Single-Bell:
- Cast Alnico 5 Magnet, designed to be used with 500k pots
- Voiced to capture that signature Fender-style single coil tone without the 60-cycle hum
- Lightly potted to minimize squeal
- Made in the USA with premium quality materials
The retail price for a Bridge and Neck matching set is $340.00 and theyāre available directly and exclusively through BelltoneĀ® Guitars / Brickhouse Toneworks at belltoneguitars.com.