Blog

We are excited to bring you our new Helix blog. We have a lot we want to share with you about Helix and this blog will feature a range of interesting articles to help you get the best out of your Helix. You'll find the latest product news, tips and tricks and demos, as well as interviews with artists. This blog captures the essence of everything Helix and we will be updating it on a regular basis, so make sure you continue to check out line6.com/helix/blog to stay informed. To learn more about Helix or to find a Helix dealer in your area please visit line6.com/helix/dealer.

2016-04-18

Why Do I Need A “Method” For My Cables?

Even if you’re a player that has little interest in the technological side of guitar, there are real sonic benefits to be had by adding even just a little “modern-ness” to your setup. Adding a little bit of technology can open doors to new places – and considering that many of our favorite songs were written after an artist was inspired by a new tone or effect, new sounds can actually be important.

If you’ve been on a guitar forum in the last few years, along with acronyms like “GAS”...

Even if you’re a player that has little interest in the technological side of guitar, there are real sonic benefits to be had by adding even just a little “modern-ness” to your setup. Adding a little bit of technology can open doors to new places – and considering that many of our favorite songs were written after an artist was inspired by a new tone or effect, new sounds can actually be important.

If you’ve been on a guitar forum in the last few years, along with acronyms like “GAS” (Gear Acquisition Syndrome) and “BITEME” (okay, I just made that one up), you’ve probably seen “4CM”, “Four Wire” or “Four Cable Method” written somewhere. These last three refer to a specific cabling scheme between a guitar amp and effects units, and it’s the routing method that I personally use nowadays when playing live.

The theory behind the Four Cable Method starts with the fact that effects behave differently depending on where they are in the signal chain. Some sound great when placed in front of an amp’s preamp section (like compressors and distortion), and some behave nicely when placed after the preamp (reverbs and delays).

It’s important to note that the preamp section of an amplifier is where the tone is first created (by adding gain, saturation and EQ to the input signal), and any effect that is connected in front of the preamp will get that same gain and saturation applied to it as well.

So the fact that I wrote “behave nicely” above is important, because sometimes you don’t want your tones to behave! The slapback delay sound on classic guitar records usually comes from the delay being in front of the amp, where the subtle bits of gain and saturation from the preamp make the delay bigger and wider sounding. If you’re going after that sound and your delay is not routed the same way, you may have to work harder to get it to sound the same.

So how do you split up the effects so that some can go in front of the amp, and some can be placed after the preamp, but before the power amp section? Is there a trick to it?

The answer is that to make the Four Cable Method work, your amplifier has to have an effects loop built in. An effects loop is usually be labeled with “send” and “return” jacks on the back panel, and in most cases the “send” acts as a “Preamp Output” and the “return” acts as a “Power Amp Input”. Basically, it’s a way to split your amplifier into two separate pieces that you can use individually.

If you have individual pedals and an amp with an effects loop, you can start experimenting with the basic principle of Four Wire by placing a distortion pedal in front of the amp, and putting a delay pedal in the loop. No matter what you do to the tone and gain knobs on your amp or the distortion pedal, the delay sound won’t change because it’s farther down the line. Once you see how that works, you can add more pedals to both the front of the amp and the loop’s return to widen your tonal palette.

At this point, some of you may have noticed that when we’re talking about connecting a bunch of individual pedals to an amp, we’d need a heck of a lot more than four cables to connect everything. So where does this “Four Wire” thing come from?

The last piece of the wiring puzzle comes from the fact that “Four Wire” almost always refers to a routing scheme where all of the effects are coming from a single effects unit. If all of the effects are coming from inside the same box, how do you send some signals to the front of the amp, and send others to the amp’s effects loop?

You guessed it: the multi effects unit has to have an effects loop too! It’s the only way to make this scenario work.

Here’s a basic Four Cable Method hookup diagram, where the arrows point in the direction the audio is being sent:

The four arrows in the above diagram refer to the “four cables” needed to make this whole thing work.

Stick with me:
1. The guitar is connected to the INPUT jack of the effects unit.
2. The signal is then sent through the effects modules (compression, distortion, modulation, etc) that you wish to connect before the preamp section of your amplifier.
3. The signal is then split inside the effects unit, and is sent out of the effects loop SEND jack.
4. The effect unit’s SEND jack is connected to the INPUT jack of the guitar amp.
5. The preamp of the amplifier then adds gain and EQ to the signal.
6. From there, the signal is sent out the amp’s effects loop SEND jack back to the effects unit’s loop RETURN jack.
7. Since any distortion effects have already been added earlier in the chain, delays and reverbs are added.
8. After the signal passes through these post-effects, it is sent to the effects unit’s main OUTPUT jack.
9. The effects unit main OUTPUT jack is connected to the amplifier’s loop RETURN jack, where the signal is then sent out to the power and amp speakers.

It sounds (and reads) more complex than it really is, I promise! It works in the same way that the basic example did but has a ton more flexibility, because you can swap out pedals on your virtual pedalboard on every patch that you make.

So the real question is, if this is the basic setup, what’s the next step in 4CM? How do you up your Four Wire game?

The quick and easy answer is, “check out Helix”.

With FOUR effect loops built in, Helix has the ability to run the Four Cable Method and still have three additional effect loops left over for other tasks! That means that you could incorporate a number of your favorite hardware effects pedals inside the Four Wire setup, which is huge. With three leftover loops and four parallel audio paths in one preset, you have tremendous flexibility – you could insert that one-of-a-kind distortion pedal you wired yourself inside the “front” chain, and still connect a stereo guitar synth in parallel with the other two loop returns. You could send just the wet output of the looper to a separate set of speakers for your drummer, or leave a dry path running through the entire signal chain. The possibilities are truly vast, and it means that you can change the tone drastically from patch to patch.

But with Helix you can go even further. The preamp models in Helix are so realistic that you may want to experiment with bypassing the preamp of your amplifier on a few patches, as a way of getting even more tonal variety out of your setup.

As a personal example, I use a combo amp on smaller gigs that employs 6v6 power tubes. Those tubes have been used in many classic power amp designs over the past fifty years, and they have a specific sonic signature that is easy to spot. Knowing this, I started by experimenting with a number of the preamp models in Helix that had 6v6 power tubes in the original power amp section. It turns out that the “US Deluxe” preamp model sounds great when mated to power section of my combo amp, and it changes the tone in a more fundamental way than simply adding a pedal to the signal chain would.

To bypass the preamp on your amplifier in a Four Wire scenario, all you have to do is NOT use the cables to the amp’s “input” or “send” jacks – just load up a preamp in Helix and send the entire finished tone to your amp’s “return” jack, and you’re ready to go. The cool thing is that you can make these changes with one footswitch, so Patch 1A can be the normal setup, and Patch 1B can use only the power amp section of the amplifier and get the entire rest of the sound from Helix.

By the way, Helix provides a factory preset (8 TEMPLATES > 02A 4-Cable Method) that accomplishes all of the above without needing to repatch anything. You can seamlessly toggle between the real preamp and one of Helix's preamp models by pressing FS2 (HELIX PREAMP).

With Helix, the Four Cable Method can become much more than a reconfigurable pedalboard and amp setup. It can use all of the goodness that your real tube amp has to offer, and then give you more tonal variation than you thought possible – all with just four cables.

I promise it’s much easier to experience this stuff than read about it, so after you’ve checked out all the media on www.line6.com/helix, head over to a Certified Helix dealer and check one out for yourself.

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2016-01-25

What The Heck Is An IR?

The music industry loves coming up with terms and acronyms to describe both new and existing technologies, and it can be daunting to try and keep up with every new phrase that comes along. Just as soon as we guitar guys finally learn what the heck a “DAW” is, another new term pops up that we either have to drop into a search engine or ask the nearest 12-year-old about.

Of the newer crop of technological terms, impulse responses or “IRs” have gained a significant amount of traction in...

The music industry loves coming up with terms and acronyms to describe both new and existing technologies, and it can be daunting to try and keep up with every new phrase that comes along. Just as soon as we guitar guys finally learn what the heck a “DAW” is, another new term pops up that we either have to drop into a search engine or ask the nearest 12-year-old about.

Of the newer crop of technological terms, impulse responses or “IRs” have gained a significant amount of traction in gear publications as of late. As well as moving music technology forward in a major way, it turns out that IRs have a lot of applications for guitarists and guitar technology – so we should know what they are.

Simply put, an impulse response is an audio file that contains a capture of the inherent sonic characteristics of a piece of gear, acoustic environment, or playback system. IRs were first used to recreate unique acoustic spaces in reverb processors, and they changed the professional music mixing game by making huge rooms like the Sydney Opera House available as studio reverbs for the first time.

As for what the audio file itself contains, an impulse response of a huge church would capture the room’s reverb decay characteristics, as well as the sonic character of the construction materials and the recording gear used for capturing the audio. An IR of a mic’d 4x12 speaker cab would capture the sound of the speaker and speaker enclosure in the room, the microphone and microphone preamp used to capture the audio, and the speaker cable used by the power amp to drive the cab.

It’s important to note that both of these scenarios involve a number of variables that can audibly affect the impulse response. For instance, if the inside of the church was covered in wall-to-wall carpet instead of stone, the reverb decays would be far shorter at some frequencies due to absorption, and thus the reverb tails would have a muffled tone when compared to the long and clear decay of a huge stone room.

After capture, a convolution processing engine takes the short impulse response file and expands it into a working model of a 4x12 speaker cabinet or huge church. At that point, the IR acts just like a preset in an effect unit and imparts the sound of the impulse file to any audio run through it.

Impulse responses are quite short, so another thing you’ll need to know is a number – usually 1024 or 2048. These relate to the number of samples used to capture the audio file, with a higher number referring to a longer capture (CD’s use 44,100 samples per each full second of audio, so you can see just how short these files are).

Just remember this basic rule: the longer the capture time, the higher the resulting accuracy.

The question is “what does all this technical mumbo jumbo mean to us guitarists”? The answer is that it means that the speaker cabinets we now use in modeling gear can potentially have a realism that wasn’t previously possible using simple filters and resonance (the old way of doing speaker emulation). It also means that we can use some available free tools to capture the sound of our own speaker cabs and mics, if we have a unit lying around that can load our homemade impulse responses.

As for the “unit lying around” part, Helix gives you the ability to load impulse responses and save them with your preset, opening an entire new world of speaker cabinet customization to you as a player. If you want to experiment but don’t have the ability to capture your own responses, there are a number of companies that sell good-sounding speaker impulse files a la carte (Red Wirez and Ownhammer being two popular choices).

After all of this talk of user customization however, it is important to note that just because something preloaded into a piece of gear isn’t listed as being an “IR” specifically, it doesn’t mean that it wasn’t created with an impulse response. For instance, in some modeling devices (Helix and the Fractal Axe FX, for example) the factory speaker cabinets are created using impulse responses. So just because you have the option to load third-party impulse responses into a device like Helix, it doesn’t mean that you necessarily have to for realism’s sake.

Lastly, it’s important to remember that running IRs is a highly DSP-intensive activity for a processor – so it’s normally only done on devices that can allocate DSP resources dynamically. We wanted to ensure that Helix didn’t automatically run out of power when running multiple speaker emulations, so we came up with a proprietary scheme we call “hybrid cabs” that grants the same resolution as an HD speaker impulse, but at lower DSP usage. If you’re interested in getting more information about hybrid cabs, I wrote a separate blog about it, available here: http://line6.com/helix/blog.html.

Impulse responses have moved music technology forward in a big way, allowing for far more realistic recreations of time-domain attributes and acoustic spaces. Helix ships with a pile of captured speaker cabs and microphones with multiple positions, and comes with an additional bunch of IRs you can load yourself for additional experimentation. Hear and feel the difference that accurate speaker cabs and mics can make at your local certified Helix dealer, and be sure to check out www.line6.com/helix for more information.

For all of you tech heads that want to know more about this entire subject, Apple does a nice job of explaining the entire thing using Logic Audio’s tools here:

https://manuals.info.apple.com/MANUALS/1000/MA1655/en_US/impulse_response_utility.pdf

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2016-01-25

Reamping – Why, How, and Why Not?

It doesn’t matter if you’re working in a professional studio or only producing music for your friends and family – if you record guitar at all, you’ve probably had the experience of hearing a final mix and wishing you could tweak things a smidge.

I’m sure we’ve all heard the finished mix of a tune we’ve played on and thought “now I wish I would have used a different microphone on that speaker cab”, or “I wish I had backed off the distortion on the solo a little bit”. The reality is...

It doesn’t matter if you’re working in a professional studio or only producing music for your friends and family – if you record guitar at all, you’ve probably had the experience of hearing a final mix and wishing you could tweak things a smidge.

I’m sure we’ve all heard the finished mix of a tune we’ve played on and thought “now I wish I would have used a different microphone on that speaker cab”, or “I wish I had backed off the distortion on the solo a little bit”. The reality is that hearing our guitar parts in a finished mix can be equally enlightening AND frightening, depending on the circumstances.

Oftentimes, the opinion a guitarist has about this subject has everything to do with what they listen to when they’re tracking. If the mix of a song is basically finished and your job as Guitar Session Guy is to come in and add the final finishing touches, chances are good that the tones and sounds you dial up will need little tweaking before the mix is called “final”. However, if what you’re hearing when you track is unmixed bass and drums, chances are very good that the sonic relationships between all the tracks will change dramatically at mixdown.

Modern recordings sound huge partially because they no longer have to be mastered for vinyl records – in the old days, too much bass in a mix would make the needle jump out of the groove on the cutting lathe. These days CD’s and MP3’s don’t skip if the kick drum is massive, so mix engineers no longer have to be anywhere near as careful about how much extreme frequency information they pump into a mix. Combine that with the fact that many recordings are not made in professionally designed acoustic spaces these days (so mix engineers employ samples and a ton of other techniques to make the tracks sound bigger), and you get a situation where the raw tracks and the finished mix may sound very different.

That has consequences for us guitar dudes though! Once the mix engineer has turned those tiny drums and bass you listened to while recording into nuclear bombs, your tracks may no longer be cutting the mustard. Maybe that warm guitar sound you chose for the bridge is now too dull to cut through the huge drums and bass, or perhaps that ton of gooey low-end information you dialed in on the verses is clouding up the now-cavernous kick drum.

You can go a long way in the mix stage using eq and compression to shape guitar sounds, but the point I’m trying to make is that the more “finished” the other sounds you hear when you’re tracking are, the easier it is to pinpoint exactly what is needed for your guitar tracks. The more rough and unfinished the backing tracks are, the more you’ll have to guess about what they’re going to sound like in the final mix when crafting your own sounds.

So what can you do to safeguard yourself in these scenarios? The answer is something that some professionals have been doing in the studio for many years: reamping.

In a scenario where you want to change the core sound of a guitar track, the term “reamping” refers to a situation where the exact same performance is used to send signal back to an amp that is then remiked and rerecorded, instead of simply replaying the guitar part with a new sound.

In order for this to function correctly, at least two tracks have to be recorded at the same time for every part: the full guitar sound that would normally be committed to tape/disk, and the direct sound (straight out of the jack) of the guitar itself. Once that direct guitar sound exists on a separate track, it can be sent back out to a real amp and re-recorded with a completely different tone. You could even use a completely different amp and cab, if you liked.

There are a number of benefits to this kind of scenario:

1. You can change the core tone of the guitar at any time: if you get to the final mix and the printed delay on the guitar track is too loud and the amp is too crunchy, reamp the track and turn down the gain and delay mix while you’re recording it back to disk.

2. You can punch into a solo or part that has printed effects at any time, even months later. Normally, punching into a part with a ton of printed time-based effects is impossible, because you can hear the punch point when the delay and reverb tails stop. With a direct track in the scenario, all you have to do is get the performance right using as many punches as you like, and then simply reamp the part using the same sound and setup. It will sound as if there are no punches at all, because as far as the reverb and delay are concerned, there really aren’t.

Once you realize the huge benefit that reamping can provide, you may be asking yourself “why doesn’t everyone do this all the time?” The answer has to do with the multiple levels of complexity that reamping requires in the real world if it’s to be done correctly:

1. The guitar signal has to be split, so that it can be run straight to the amp and also to the recording interface at the same time. The important part to know is that most electric guitars have passive pickups, so splitting the guitar signal right after the guitar is fraught with danger. If the split isn’t done with an active/buffered splitter (instead of a simple “Y” cable) an impedance mismatch happens, and the guitar pickups are loaded incorrectly. An improperly loaded guitar both sounds and feels terrible, so it should be avoided at all costs.

2. The output of an electric guitar differs quite a bit from the line output of a recording interface or recording console, in that it is really quiet in comparison. Just as importantly, the input circuits of tube amplifiers expect to see this level from an electric guitar, not the loud line level from a console. These two facts dictate that once the direct guitar sound is recorded to tape/disk, it has to be modified before being sent back to the front of the amp for reamping. If the amp doesn’t see exactly the same signal and impedance that it would when connected directly to the guitar, it won’t sound the same when reamped.

Professional studios have always had custom gear and experienced tech staff to setup and maintain scenarios like this, so the entire reamp experience has been an exclusive thing until recently. However, now there is a much easier way to accomplish this reamping stuff, because Helix has reamping built-in and pre-routed, when used with a DAW over USB.

By default, Helix automatically passes the direct guitar sound (pulled right from the guitar input before any processing) to your computer’s DAW on USB Channel 7, so you don’t need to do anything to set it up. Just create a track for the normal Helix output coming over USB Inputs 1/2, and another track for the direct guitar sound on USB Input 7. You’ll want to set the output of your direct track to a different USB channel than your stereo mix (USB output 5, for example), and then press record. That’s it! If you need to punch in on a performance, go ahead and punch as many times as you need to get the perfect take.

When you want to reamp and change the core tone, simply set the input on the Helix hardware to be USB 5, and you’re ready to go. That’s it: the direct track will stream back into the Helix signal chain at exactly the same level as it did when you were playing it live with your guitar, so the tone and gain will be exactly the same. You could even use one of the effects sends (set to “Instrument” level) to send the direct guitar track to a real amplifier, if you like.

Helix makes the process of reamping so easy that you owe it to yourself and your music to check it out at a store near you soon. Before you go, head to www.line6.com/helix for more information.

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2016-01-15

All Hands Off Deck

In our modern lives we encounter the work of product designers nearly every minute of every day. Every chair we sit on, every door we open, and every button we press started out life as a thought in the head of a designer somewhere, before being made into a product.

Poor designs call attention to themselves by annoying the bejesus out of us (“why is the button for my gas tank in the freaking glove box?”), while good designs become almost transparent – a part of the fabric of modern...

In our modern lives we encounter the work of product designers nearly every minute of every day. Every chair we sit on, every door we open, and every button we press started out life as a thought in the head of a designer somewhere, before being made into a product.

Poor designs call attention to themselves by annoying the bejesus out of us (“why is the button for my gas tank in the freaking glove box?”), while good designs become almost transparent – a part of the fabric of modern life that we ignore because they do their jobs effortlessly.

The fact is that we deal with good designs on a daily basis and they’re all around us. Nowadays no one thinks about life before paperclips or belt loops, or life without dead bolts or windshield wipers (or, in my case, automatic home espresso machines), but we notice these things when we’re in need of them and they’re missing.

It is precisely this relationship between human nature and design that can make it difficult to come up with something new, because it takes concerted effort to find a new way to do the same thing better.

Take guitarists, for example. The gear we know and use has changed very little since the 1960’s, in terms of how we interact with it. The guitar gear of today may have more knobs than it used to, and it may be able to do eighty things at once, but the fact remains that it still has knobs. Why? Because we still use our fingers to tweak everything.

The problem is that playing guitar and tweaking knobs can’t really be done at the same time – you actually have to stop doing one thing to do the other. Guitarists are so used to the rhythm of “PLAY-tweak-PLAY-tweak-PLAY” that it feels like “that’s the way it is” to us, and little thought has been given to an alternative. Even though some adventurous manufacturers have tried over the years, no one has yet been able to effectively challenge this way of thinking.

When we were designing Helix, we knew that having touch-sensitive footswitches meant that you could assign an effect to a footswitch in three seconds. It also meant that you could use all of those assigned switches to navigate through the user interface very quickly and pick what you wanted to edit. It was a huge step in the right direction, because it lets the user get around far quicker than they would by moving a joystick back and forth.

But you still needed to use your fingers to tweak the knobs, so it wasn’t fast enough yet.

At some point we realized that guitarists actually DO have the onboard equipment needed to do things faster. In fact, they already knew how to incorporate these body parts into a performance because they’d been doing it for their entire lives as electric players.

I’m talking about feet. Yup. The majority of electric guitarists not only have feet, but many of them are actually comfortable manipulating pedals while playing (wah wah and volume pedals were great training tools in this regard). We thought, “why not try and use that familiarity to create a new way of tweaking stuff”?

That thought was the beginning of what eventually became Pedal Edit Mode – a state on Helix where every parameter on any loaded effect block can be tweaked with the expression pedal. Even though it might sound a bit odd at first, most radical technological advances in modern life do. Think about it: when someone first suggested that you would swipe your finger across the face of your phone to navigate to the next photo, it sounded weird. Now it’s second nature to most people, as Pedal Edit Mode-style editing will likely be to guitarists in years to come.

When you get a chance, you owe it to yourself to find your local Certified Helix dealer, and try out Pedal Edit Mode for yourself. Pick a preset, and then hold down the MODE footswitch for three seconds to enter Pedal Edit. Then think about what parts of the guitar tone you’d like to tweak, and make those changes using the expression pedal.

I imagine that you’ll have a similar experience to the one I had when I tried it for the first time: the initial weirdness that I felt was almost instantly replaced with comfort, realizing that I could continue playing the same riff over and over while I tweaked the amp and effects parameters without stopping. After that first few seconds it was instantly familiar, and it felt natural.

For more information on Pedal Edit Mode and Helix in general, check out www.line6.com/helix, and then find a Certified dealer and try one out for yourself.

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2016-01-15

Wet Dry Wet

It goes without saying that the order in which you set up your guitar effects has a lot to do with the way your rig sounds. If you put a delay effect in front of your amp, it takes on a much more saturated and in-your-face character than if it were after it.

Most guitarists run their effects serially (meaning ‘one-into-the-next’), in variations of this kind of setup:

However, things get more interesting if you’re not forced into a purely serial routing scenario....

It goes without saying that the order in which you set up your guitar effects has a lot to do with the way your rig sounds. If you put a delay effect in front of your amp, it takes on a much more saturated and in-your-face character than if it were after it.

Most guitarists run their effects serially (meaning ‘one-into-the-next’), in variations of this kind of setup:

However, things get more interesting if you’re not forced into a purely serial routing scenario. Separating some of the signals from each other can yield some real sonic benefits, but up until now it has only been widely achievable in the recording studio, or onstage in a complex and expensive setup.

The term “wet-dry-wet” or “WDW” has come to describe one such routing scenario, where the main guitar sound comes out dry, and the post-amp modulation and time-based effects come out a separate set of speakers in stereo, set to 100% wet. Like this:

The benefit of this scenario is improved clarity, as the 100% wet effects are simply added to the dry tone and don’t replace it at high mix settings. Set correctly, the dry tone is never swamped or taken over by the effects – the patch can sound huge, but the dry guitar pokes out easily because it’s being summed with the wet sounds at the end of the line, and not going through them serially. Regarding the wet setting - this is important, folks - any effects on parallel paths usually need to be set to 100% wet to avoid phasing issues.

It’s also important to note that you don’t have to set up a pure “WDW” scenario to see a benefit from the concept. Check out this patch in Helix below:

Here I’ve created a hybrid setup, taking advantage of a pair of Helix’s four stereo paths available per patch. The signal splits after the amp, so one path feeds a reverb effect directly, and the other path feeds a delay effect set to 100% wet. The delay then rejoins the main signal path after the reverb.

Why do this? If you look at the routing you can see that all I’ve done is prevent the delay repeats from hitting the reverb. The benefit – and the reason why I set up nearly all of my patches in Helix this way – is that the delay repeats don’t fill up the reverb with their energy, which can make things sound muddy. In this kind of setup the entire sound has been cleaned up a little – the delays stay clear and distinct, as they aren’t being diffused or blurred by the reverb, and the reverb is only heard when the guitar is playing live, not when the delays repeat.

This parallel concept is how I usually mix guitars in the studio, so it’s fantastic to have the ability to take these sounds onstage without a needing pile of gear. The possibilities are immense and exciting – and there are sounds that you can achieve by routing this way that simply aren’t possible in other scenarios.

Don’t worry if this all looks a bit scary – it’s actually not hard at all to accomplish with Helix. In fact, we’ve included a bunch of templates to let you experiment with these scenarios right from the start, so you can see if it’s something that agrees with your playing style.

For me, parallel stuff is all about definition. Even with a relatively “wet” patch swimming in swirly goo, I can still hear the notes pop out easily routing this way. Check out some of the sound samples at https://soundcloud.com/line6/sets/helix or some examples of how these patches really make a difference, and maybe someday soon I’ll do a deeper dive into this world, if enough of you folks let us know that you’d like me to. Happy tone sculpting!

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2016-01-13

Give Your Panda A Bucket

Students usually find that there are a few basic rules to follow when learning any new discipline – most of which are really just refined examples of “best practices” taken from years and years of experience in that field. Chefs learn that a cooked steak needs to rest before being cut on the bias, electricians learn to test high voltage wires with the back of their hands not their open palms, and scientists learn how to test observations using the Scientific Method.

For engineers, a...

Students usually find that there are a few basic rules to follow when learning any new discipline – most of which are really just refined examples of “best practices” taken from years and years of experience in that field. Chefs learn that a cooked steak needs to rest before being cut on the bias, electricians learn to test high voltage wires with the back of their hands not their open palms, and scientists learn how to test observations using the Scientific Method.

For engineers, a classic example of one such rule is “noise is a by-product of inefficiency”. This one is observable every time you hear a muscle car from two blocks away yet can’t hear a luxury sedan idling next to you: the muscle car has a ton of power and can reach high speeds, but that power comes at the expense of efficiency, and the by-product of that inefficiency is excessive noise and lower gas mileage.

But enough of the Science Speak! This kind of stuff is relevant for pure designs, but we’re guitar players! We distort things on purpose! Like, really distort the bejesus out of them, sometimes. We often want a guitar to be that muscle car, so to speak, and we just deal with any added noise as a necessary evil of getting the sound we want. When it comes to guitar tones, pure science must sometimes be mixed with the smelly stuff.

Case in point: some of the most sought-after delay pedals ever made make use of a “Bucket Brigade” (“BBD”) chip under the hood. These are idiosyncratic devices with all sorts of design shortcomings, but BBD chips have gooey and organic sonic attributes that play an essential part in some of the most revered guitar sounds of all time.

The chip got the name “bucket brigade device” due to the way that each stage handed off audio to the next – mimicking the way that buckets of water were passed from person-to-person to fight fires before the dawn of fire hydrants. The chip itself is interesting in that it’s analog, but the delay time is controlled digitally by altering the sample rate.

This is important because when you decrease the sample rate, you are effectively lowering the resolution of the audio passing through the chip by moving the samples farther apart. Lower resolution means that the audio sounds more processed and a bit nasty.

Did I mention that BBD’s are also noisy, and roll off quite a bit of high-end as well?

So you have a noisy chip that sounds dull, has relatively short available delay times and gets funky-sounding at the longest settings. Sounds like a terrible design! However, BBD-based delays have been holding down spots on pedal boards for 30 years now, so there must be something more going on.

Oddly enough, the chip’s shortcomings were part of what made it useful for guitarists. The treble roll-off is beneficial because the delayed notes are slightly duller-sounding than the originals. This means that the repeats stay out the way of live playing, and the delay rarely sounds harsh. A compander (compressor/expander) circuit was added to try and tame the noise by turning up the level of the repeats as they began to decay – which mostly worked – but as a bonus it added a wonderful organic gooeyness to the sound of the repeats due to the added compression.

Due to all of these idiosyncratic characteristics, it has been nearly impossible to create a faithful bucket brigade delay in embedded software up to this point. Previous guitar products have been able to mimic the real behavior for a few knob settings, but for Helix we wanted to go further. We wanted to offer fully realistic recreations of these classic pedals, where not only was the knob interaction correct, but the distinctive audio artifacts were preserved as well.

In the end, we created two self-governing software components specifically for these delay pedals: a bucket brigade chip we call “Bucketier”, and a compander circuit we call “Panda”.

Both of these components run standalone in the virtual delay circuits, behaving precisely as their analog counterparts do. Panda creates the same glued-together dynamic behavior that the original circuit had, and Bucketier performs the change in delay time by altering its own internal sample rate, thereby recreating the same lossy resolution as the original units at long delay times. In addition, having the Bucketier as a standalone component means that we can create variations of these pedals that would have been prohibitive to make in the real world, while still retaining the authentic behavior of the original bucket brigade chip. As an example, the Adriatic Delay in Helix has the ability to add additional BBD chips for longer delay times than would have been possible on the original modeled pedal.

So if you’re a vintage delay junkie, you owe it to yourself to find a Certified Helix dealer and check one out – it’s vintage gooey delay heaven. For more information on all of this stuff, check out www.line6.com/helix.

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2016-01-11

Throbber. No, Really.

Even though some designs are simple and have a small number of common components, many classic effects pedals have some interesting stuff going on under the hood, circuit-wise. Some of these pedals rely on unexpected components to help create their signature sound.

A case in point is the Uni-vibe pedal, originally made by Shin-ei in Japan and later sold by Univox*. Hidden beneath the metal case sits a functioning incandescent light bulb, which is surrounded by four photocells....

Even though some designs are simple and have a small number of common components, many classic effects pedals have some interesting stuff going on under the hood, circuit-wise. Some of these pedals rely on unexpected components to help create their signature sound.

A case in point is the Uni-vibe pedal, originally made by Shin-ei in Japan and later sold by Univox*. Hidden beneath the metal case sits a functioning incandescent light bulb, which is surrounded by four photocells.

Yup, you read that correctly! A light bulb shining inside your guitar pedal, similar to one you’d find in a very small flashlight.

Original Uni-vibe pedals and their copies have a watery, syrupy, gooey character, popularized by influential guitarists like Jimi Hendrix and Robin Trower, and also by modern players like Mike Landau. It’s a distinctive effect that is instantly recognizable, and it’s an essential component to what is commonly referred to as the “psychedelic” guitar sound. I personally dig it enough that I used it extensively in the Helix introduction video, which you can check out here, if you haven’t seen it yet: www.youtube.com

From a digital point of view, the problem with light bulbs (which are in charge of much of the modulation characteristics of the Uni-vibe) is that they are decidedly non-linear. This means that if you were to watch high-speed footage of a light bulb dimming and brightening, you’d see that it doesn’t go from bright to dark evenly. It may take some extra time to get to full brightness as the filament begins to glow, and then dim slowly as the current ebbs away.

Not only that, as there is no industrial spec for these bulbs, they all behave a little differently. Some bulbs get brighter than others, while some take longer to light up and dim than other bulbs from the same batch. In fact, one of the reasons why individual Uni-vibe pedals are famous for sounding different from one another is due to bulb-to-bulb variance (the other is the existence of an internal lamp bias trim pot that most guitarists didn’t know was in the circuit for much of its history).

The point behind all of this is that you won’t be able to make a killer Uni-vibe type effect in software until you can predict and recreate the chaotic behavior of a light bulb. It just won’t sound the same, as that crazy non-linearity is part of what makes a vibe sound thick and watery.

We wanted to go much further than simply describing how a bulb behaves in Helix, so we built a fully-functioning virtual light bulb in software. It’s called “Throbber”, and it’s one of the core elements that make the Uni-vibe emulation in Helix so lifelike. Helix even allows you to adjust the electrical bias of the lamp itself, which gives you the ability to customize the shape of the vibe effect just like the real ones could (although unlike the real pedal, it doesn’t require a screwdriver).

With the Uni-vibe effect in Helix you can go from a Jimi Hendrix-type vibe to Daniel Lanois-styled sound with the flick of a knob, and it works as it should both before and after a drive pedal in front of the amp.

Once you’ve checked out the video link above, check out the rest of the Helix media at line6.com/helix to see what the buzz is all about.

* Uni-Vibe is a registered trademark of Dunlop Manufacturing, Inc. The Uni-vibe product discussed above is the original Shin-ei Uni-Vibe product, which is longer made. No reference to the Uni-Vibe product currently marketed and sold by Dunlop Manufacturing, Inc. is used or implied.

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2016-01-08

Transtronic - recreating the past while preparing for the future.

Guitarists like to distort things - like, REALLY distort things – and all of the devices that we used for this task before the dawn of digital guitar products employed diodes and/or transistors to do the job. Even though they can appear quite small when looking at a circuit board, these components are complex and interactive little blobs of electrical goodness that are intrinsically important to the history of guitar music.

Before diving in I should say that the core of this subject...

Guitarists like to distort things - like, REALLY distort things – and all of the devices that we used for this task before the dawn of digital guitar products employed diodes and/or transistors to do the job. Even though they can appear quite small when looking at a circuit board, these components are complex and interactive little blobs of electrical goodness that are intrinsically important to the history of guitar music.

Before diving in I should say that the core of this subject has been covered ad infinitum on the Interwebs, and if anyone reading this wants to get the lowdown on how these things truly work, a quick perusal of the web using your search engine of choice should yield hours of fun reading. For the rest of you, let’s consider this to be the Cliff Notes version.

All you need to know about transistors and diodes in guitar pedals is that they’re really just used as small amplifiers/gain boosters or clippers in a circuit. Their job is to take a smaller amount of signal and make it much larger, or clip the bejesus out of it so that it sounds to us guitarists like distorted rock and roll.

In doing their jobs in a circuit, transistors and diodes reveal a number of unique attributes, one of which is that they are very sensitive to changes in signal level. A great old fuzz pedal will sound completely different depending on where the guitar’s volume knob is set, and how the guitar itself is played. Turn the guitar knob down on some models and the tone cleans up remarkably, turn it down on others and the guitar spits out the notes as if it had just been told it owes you money.

Along with the basic construction of these components, the material that they’re made out of affects how they sound and behave as well. Germanium was the first material that transistors were made out of when they came to be at Bell Labs in 1947, and that material was consistently used in transistors until the early seventies when silicon versions replaced it.

Silicon replaced germanium largely because it was a “better” material - more temperature stable, less noisy and more consistent – but it does actually sound and feel different. Germanium designs are often described as “looser and smoother” sounding relative to their silicon counterparts, with germanium designs yielding more touch sensitivity and gooey feel. Both materials have valid uses, and guitarists are split evenly on the subject of which is the best type to use. Incidentally, starting a “silicon vs. germanium” thread on your favorite BBS is a perfect way to start an amusing shouting match, if you’re ever sick in bed with access to the Internet but not to ‘Top Gear’ reruns.

The challenge for an engineer attempting to digitally recreate a pedal design utilizing these parts is that the transistor is much like a tube: it behaves differently with miniscule changes in signal level or voltage and current (the more complex a component’s behavior, the harder it is to recreate digitally). This has historically meant that digital recreations of classic distortion and fuzz pedals have only been able to get so far: in order to do it right, you would need a self-governing recreation of a transistor and diode itself, to sit in a virtual circuit and behave like the real thing.

This is precisely what was done for the HX models in Helix, with the creation of Transtronic.

With Transtronic, Helix can recreate the behavior of virtually any type or style of transistor and diode, whether it be made out of germanium or silicon, in any variation of PNP or NPN package type. Transtronic makes it possible to model pedals that were previously thought to be impossible, and it reacts just like the real thing. The Industrial Fuzz can break into full teeth-grinding oscillation at some settings, and it can snit and snat just like the hardware when you roll the volume knob down. The Octave Fuzz effect works exactly like the vintage model, and those that know you have to switch to the neck pickup and dial down the guitar’s volume to get the classic Jimi tone will be rewarded with 60’s psychedelic authenticity.

Transtronic is just one of the arrows in the HX modeling quiver, so if you’re a fan of distortion and fuzz you owe it to yourself to find a Helix and give it a spin. Pick an amp and pedal combination that you’re familiar with in the real world, and put it through its paces. We’re confident that you’ll be surprised at the level of authenticity of these classic effects, because we were too!

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2015-09-15

Helix Hybrid Cabs

In any digital device, there will always be some functions that require a large amount of horsepower to accomplish and others that are far more efficient. If you think about devices that you use every day, typing an email on your computer or smart phone feels quick and responsive because generating text is easy for the processor. Watching a full HD movie is a different story however, because video requires much more DSP overhead to display.

In any digital device, there will always be some functions that require a large amount of horsepower to accomplish and others that are far more efficient. If you think about devices that you use every day, typing an email on your computer or smart phone feels quick and responsive because generating text is easy for the processor. Watching a full HD movie is a different story however, because video requires much more DSP overhead to display.

In our world of digital audio, time-based effects are often the most DSP-intensive, with delays, reverbs, amps and speaker cabinets topping the list of the hungriest processes.

Speaking of hungry processes, speaker cabinet emulations that are created using impulse responses (like the ones in Helix) traditionally use a large amount of DSP. This is due to the fact that these impulse responses are actually short audio recordings containing capture data from a mic’d speaker cabinet. The higher the quality and the longer the recording, the more accurate and detailed the speaker emulation is, but that increase in quality has a greater DSP load.

Along with its suite of internal speaker cabinet models, Helix also allows you to load high-quality impulse responses from third parties. While this is a fantastic option to have, it’s important to note that the factory speaker cabinets in Helix offer a number of advancements over traditional static third-party impulses.

We call the speaker emulations in Helix “hybrid cabs”, because they use a number of proprietary algorithms to reproduce the same frequency and dynamic accuracy typically seen in a 2048-point impulse response, but at far lower DSP usage.

Not only that, a hybrid cab allows you to move the microphone from directly on the grill to up to 12 inches away (in .5 inch increments), and accurately captures the proximity effect/bass boost of the microphone in all positions while doing so. All of this detail means that the speaker cabinet reacts just like the real thing, not just sounding better but feeling better under your fingers.

Due to the efficiency improvements hybrid cabs offer, it’s actually possible to run up to four speaker cabinets at once in Helix (depending on DSP load), all with different microphones and microphone positions!

The main thing to get out of all of this is that while Helix offers the ability to load third-party impulse responses, you shouldn’t feel that it’s necessary to do so to get fantastic tones. HX cabs offer authentic speaker and microphone behavior with more flexibility and lower DSP usage, leaving you more processing headroom for effects.

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