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 ‘59 Fender Bassman cranked up through its internal 4x10” speaker configuration sounds nothing like a Mesa Dual Rectifier through its oversized, closed-back 4x12” cabinet with Celestion Vintage 30s. And the speakers and speaker cabinet are a huge part of the equation—if you were to run the Mesa Recto into the Bassman speakers, you’d get a completely different tone, but one that leans in the classic Bassman direction.
The same thing goes for Vox tones—try running almost any amp into an open back 2x12” with Celestion Blues and you’ll instantly see just how much of that classic Vox character is actually coming from the cabinet.
It’s 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 doesn’t replicate many of the complex factors that come into play when mic’ing a speaker—the 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 technology—like a mic’d 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 amp’s 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 mic’ing combinations. You can mix and match and blend virtual cabinets to your heart’s content. And when you land on a sound you really like, it’s easy to store that sound within your DAW, so you can call it up again later.
Of course, you can’t 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 you’ll 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, I’ve 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 mic’ing 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.
Let’s 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 won’t 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 Control—Mastering Fake Spaces ... ›
- The Recording Guitarist: Speakers? We Don't Need No Stinking ... ›
- Amp Mic'ing vs. Impulse Responses - Premier Guitar ›
Stompboxtober is rolling on! Enter below for your chance to WIN today's featured pedal from Peterson Tuners! Come back each day during the month of October for more chances to win!
Peterson StroboStomp Mini Pedal Tuner
The StroboStomp Mini delivers the unmatched 0.1 cent tuning accuracy of all authentic Peterson Strobe Tuners in a mini pedal tuner format. We designed StroboStomp Mini around the most requested features from our customers: a mini form factor, and top mounted jacks. |
Cort Guitars introduces the GB-Fusion Bass Series, featuring innovative design and affordable pricing.
Cort Guitars have long been synonymous with creating instruments that are innovative yet affordably priced. Cort has done it again with the GB-Fusion Bass series. The GB-Fusion builds upon Cort’s illustrious GB-Modern series and infuses it with its own distinctive style and sound.
It starts with the J-style bass design. The GB-Fusion features a solid alder body – the most balanced of all the tonewoods – providing a fantastic balance of low, mid, and high frequencies. The visually stunning Spalted maple top extends the dynamic range of the bass. A see-through pickguard allows for its spalted beauty to show through. The four-string version of the GB-Fusion is lacquered in a supreme Blue Burst stained finish to show off its natural wood grain. The five-string version features a classic Antique Brown Burst stained finish. A bolt-on Hard maple neck allows for a punchier mid-range. An Indian rosewood fretboard with white dot inlays adorns the 4-string Blue Burst version of the GB-Fusion with an overall width of 1 ½” (38mm) at the nut, while the GB-Fusion 5 Antique Brown Burst features a Birdseye Maple fretboard with black dot inlays and an overall width of 1 7/8” (47.6mm) at the nut. Both come with glow in the dark side dot position markers to help musicians see their fretboard in the dark. The headstock features Hipshot® Ultralite Tuners in classic 20:1 ratio. They are cast of zinc with aluminum string posts making them 30% lighter than regular tuners providing better balance and tuning accuracy.
Cort’s brand-new Voiced Tone VTB-ST pickups are the perfect J-style single coil with clear and robust bass sounds and classic warmth. The GB-Fusion comes with a 9-volt battery-powered active preamp to dial in the sound. With push/pull volume, blend knob, and 3-band active electronics, players can access a wide array of tones. The MetalCraft M Bridge is a solid, high-mass bridge. It provides better tone transfer and makes string changes easy. Strings can be loaded through the body or from the top giving players their choice of best string tension. The MetalCraft M4 for 4-string has a string spacing of 19mm (0.748”) while the MetalCraft M5 is 18mm (0.708”). Speaking of strings, D’Addario® EXL 165 strings complete the GB-Fusion 4. D’Addario EXL 170-5SL strings complete the GB-Fusion 5.
Cort Guitars prides itself on creating inventive instruments musicians love to play. The GB-Fusion Bass Series is the latest and greatest for musicians looking for a stellar bass guitar that is not only economical, but has the reliable robust sound needed to hold up the back end in any playing situation.
GB-Fusion 4 Street Price: $699.99
GB-Fusion 5 Street Price: $849.99
For more information, please visit cortguitars.com.
Here’s a look under the hood of the funky rhythm-guitar master’s signature 6-string.
Hello and welcome back to Mod Garage. Since we’re still celebrating the 70th birthday of the Stratocaster, this month we will have a look under the hood of the Fender Cory Wong model to see just what’s so special about it. (I can tell you—it’s special!)
Guitarist, songwriter, and producer Cory Wong is renowned for his solo work, his band Fearless Flyers (with Mark Lettieri, Joe Dart, and Nate Smith), and collaborations with artists such as Vulfpeck, Jon Batiste, and Dave Koz. His playing style is deeply rooted in funk rhythm guitar, with a heavy dose of rock and jazz. Well-known for playing a Stratocaster, his signature model was released in 2021, and it’s a unique offering. If you want to build your personal Cory Wong Strat, here is your shopping list, starting with the primary structure:
• Alder body, scaled down to slightly smaller than a regular Stratocaster, with Fender American Ultra body contours
• Maple neck with a rosewood fretboard with rolled edges, modern Fender American Ultra D neck profile, slightly larger headstock, 25.5" scale, 10" to 14" compound radius, 22 medium jumbo frets
• Locking tuners with all short posts, a bone nut, and two roller string trees
• Vintage-style 6-screw synchronized tremolo
• Hair tie around the tremolo springs (which mutes them to enhance the rhythm tone)
• .010–.046 strings (nickel-plated steel)
“While these are all interesting features, resulting in a very comfortable guitar, you don’t need to copy every detail to transform one of your Stratocasters into a Cory Wong-style Strat.”
For the physical build, as you can see, Wong and Fender created a real signature instrument to his specs and wishes. While these are all interesting features, resulting in a very comfortable guitar, you don’t need to copy every detail to transform one of your Stratocasters into a Cory Wong-style Strat. My personal favorite of these is the hair tie for muting the tremolo springs. A lot of my funk-playing customers are doing similar things on their Strats to get a dry sound, and they’re using all kinds of funny things in there, like foam, rubber bands, and pieces of cotton, as well as hair ties.
Now, let’s have a look at the electronics:
• Seymour Duncan Cory Wong Clean Machine SSS pickup set
• Standard 5-way pickup-selector switch with classic Strat switching matrix
• 250k master volume pot with a 90/10 audio taper and Fender treble-bleed circuit PCB
• 250k tone pot with a 90/10 audio taper and Fender Greasebucket tone control PCB for only the neck pickup
• 250k audio push-push tone pot with Fender Greasebucket tone control PCB for only the bridge pickup; the push-push switch overrides the 5-way switch and defaults to middle + neck pickup (in parallel) as a preset
• Middle pickup is without tone control
Let’s break this down piece-by-piece to decode it:
Pickups
The pickup set is a custom SSS set from the Seymour Duncan company with the following specs:
• Overwound hum-canceling stacked bridge pickup with a 3-conductor wire and shield in permanent hum-canceling mode (red wire taped off), bevelled alnico 5 magnets, approximately 14.5k-ohm DCR
• Overwound middle single-coil, RWRP, beveled alnico 4 magnets, approximately 7.1k-ohm DCR
• Overwound neck single-coil, bevelled alnico 4 magnets, approx. 7.0k-ohm DCR
The pickups are voiced for clear highs, which perfectly suits Wong’s funky playing style and tone. While a lot of pickup companies will have pickups in that ballpark, it will be difficult to put together a full set that really works as intended. The Duncans in the Cory Wong Strat are available as a balanced set, so if you want to get as close as possible, I think this is your best bet.
5-Way Pickup Selector Switch
Nothing special here, just the standard 5-way switch with two switching stages that is wired like a classic Stratocaster:
bridge
bridge + middle in parallel
middle
middle + neck in parallel
neck
The upper tone pot is assigned to the neck pickup, while the lower tone pot is connected to the bridge pickup, leaving the middle pickup without tone control.
Master volume pot and treble-bleed circuit.
The 250k master volume pot is a standard CTS pot with a 90/10 audio taper found in all U.S.-made Fender guitars. The volume pot has the treble-bleed circuit from the Fender American Pro series, but uses a ready-to-solder PCB from Fender instead of individual electronic parts. The PCB is available from Fender individually (part #7711092000), but I have some thoughts about it. While using a PCB makes a lot of sense for mass production, it has some downsides for us mortal human beings:
• Soldering on PCBs requires some training and also special soldering tools.
• The PCB is quite expensive, while the individual electronic parts are only a few cents.
• The PCB uses ultra-tiny surface-mount parts, so it’s very difficult to repair or mod it to your personal taste.
I don’t think we need a PCB for adding a treble-bleed circuit, so let’s do this project using conventional electronic parts. The treble-bleed PCB contains a 1200 pF capacitor with a 150k-ohm resistor in parallel, plus another 20k-ohm resistor in series. Using individual parts, it looks like this:
Courtesy of single-coil.com
In general, a treble-bleed circuit will help you to combat the “volume vs. tone problem” when using passive single-coil pickups. When you turn down the volume (even just a bit), the high end or treble loss is not proportionate. In other words, a small cut in volume creates a far greater loss in your guitar’s treble response. Using a treble-bleed circuit is an easy way to get rid of this problem, as long as it is calculated carefully.
ONLINE ONLY: If you want to find out more about treble bleed circuits please have a look here: https://www.premierguitar.com/diy/mod-garage/treble-bleed-mod
Next month, we will continue with part two of the Cory Wong Stratocaster wiring, bringing it all together, so stay tuned!
Until then ... keep on modding!
This four-in-one effects box is a one-stop shop for Frusciante fans, but it’s also loaded with classic-rock swagger.
Great, lively preamp sounds. Combines two modulation flavors with big personalities. One-stop shop for classic-rock tones. Good value.
Big. Preamp can’t be disengaged. At some settings, flanger effect leaves a little to be desired.
$440
JFX Deluxe Modulation Ensemble
jfxpedals.com
When I think of guitarists with iconic, difficult-to-replicate guitar tones, I don’t think of John Frusciante. I always figured it was easy to get close enough to his clean tones with a Strat and any garden-variety tube amp, and in some ways, it is. (To me, anyway.) But to really nail his tone is a trickier thing.
That’s a task that Jordan Fresque—the namesake builder behind Sault Ste. Marie, Ontario’s JFX Pedals—has committed significant time and energy into tackling. His Empyrean is a five-in-one box dedicated to Frusciante’s drive and dirt tones, encompassing fuzz, boost, and preamp effects. And his four-in-one, all-analog Deluxe Modulation Ensemble reviewed here is another instant Frusciante machine.
The Frusciante Formula
Half of the pedal is based off of the Boss CE-1, the first chorus pedal created. The CE-1 is renowned as much for its modulation as for its preamp circuit, which Boss recently treated to its own pedal in the BP-1W. The other half—and the pedal’s obvious aesthetic inspiration—is the Electro-Harmonix Deluxe Electric Mistress, an analog flanger introduced in the late ’70s. Frusciante fans have clamored over the guitarist’s use of the CE-1 for decades. The Chili Peppers 6-stringer reportedly began using one in the early ’90s for his chorus and vibrato tones, and the preamp naturally warmed his Strat’s profile. Various forum heads claim John dug into the Electric Mistress on tracks like “This Is the Place” off of 2002’s By the Way. The Deluxe Modulation Ensemble aims to give you the keys to these sounds in one stomp.
JFX describes the DME as “compact,” which is a bit of a stretch. Compared to the sizes of the original pedals its based on? Sure, it’s smaller. But it’s wider and deeper than two standard-sized pedals on a board, even accounting for cabling. But quibbles around space aside, the DME is a nice-looking box that’s instantly recognizable as an Electric Mistress homage. (Though I wish it kept that pedal’s brushed-aluminum finish). The knobs for the Mistress-style as well as the authentic Boss and EHX graphics are great touches.
The flanger side features a footswitch, knobs for range, rate, and color, and a toggle to flip between normal function and EHX’s filter matrix mode, which freezes the flange effect in one spot along its sweep. The CE-1-inspired side sports two footswitches—one to engage the effect, and one to flip between chorus and vibrato—plus an intensity knob for the chorus, depth and rate knobs for the vibrato, and gain knob for the always-on preamp section. The DME can be set to high- or low-input mode by a small toggle switch, and high boosts the gain and volume significantly. A suite of three LED lights tell you what’s on and what’s not, and Fresque even added the CE-1’s red peak level LED to let you know when you’re getting into drive territory.
The effects are wired in series, but they’re independent circuits, and Fresque built an effects loop between them. The DME can run in stereo, too, if you really want to blast off.
I Like Dirt
The DME’s preamp is faithful to the original in that it requires a buffered unit before it in the chain to maintain its treble and clarity. With that need satisfied, the DME’s preamp boots into action without any engaging—it’s a literal always-on effect. To be honest, after I set it to low input and cranked it, I forgot all about Frusciante and went to town on classic-rock riffs. It souped up my Vox AC10 with groove and breadth, smoothing out tinny overtones and thickening lead lines, though higher-gain settings lost some low-end character and overall mojo.
The chorus nails the wonky Frusciante wobble on “Aquatic Moth Dance” and the watery outro on “Under the Bridge,” and the vibrato mode took me right through his chording on 2022’s “Black Summer.” On the flanger side, I had the most fun in the filter matrix mode, tweaking the color knob for slightly different metallic, clanging tones, each with lots of character.
The Verdict
If you’re a Frusciante freak, the Deluxe Modulation Ensemble will get you within spitting distance of many of his most revered tonal combinations. If you’re not, it’s still a wickedly versatile modulation multitool with a sweet preamp that’ll give your rig instant charisma. It ain’t cheap, and it ain’t small, but JFX has squeezed an impressive amount of value into this stomp