Blog Archive

Tuesday, November 15, 2011

Interview: Cliff Chase from Fractal Audio

MGS - Welcome Cliff Chase from Fractal audio to
CC - Thanks Tony. Pleasure to speak with you.

MGS - Can you please start with your history in the music business and how it lead you to doing what you are doing now?
CC - Well... I've been a guitar player for over 25 years and an Electronics Engineer for over 20. For the previous years prior to starting Fractal Audio Systems I worked in the underwater acoustics industry designing high-end imaging sonars. But m
y real love has always been music and I'd tinkered with various projects on and off.

About four to five years ago I started experimenting with some reverb algorithms. I wrote a program where you could input the dimensions and materials of a room and the program would simulate the reverb of that room. It worked quite well so I started expanding my efforts to other effects. Originally I had envisioned making the ultimate effects processor. Then Analog Devices came out with this new DSP chip and gave me an evaluation kit. I started writing effects routines for it and it quickly became apparent that this new chip was really revolutionary.
Intrigued by this ability to put the power of a desktop PC in a small box I turned my attention to amp modeling.

Next thing I knew I had a laboratory full of test equipment, vintage amplifiers, computers, microphones and several cats. Fast forward to today and you have the Axe-Fx.

MGS - I have been hearing reports about your new product and it is surpassing the current crop of guitar modelers in the tone dept. What are you doing that makes the modeled amp sounds better that whats out there now?
CC - If I told you I'd have to kill you... Seriously though it's probably a combination of things. When I first began I had no starting point. I had no idea what other people were doing and there is very little, if any, information readily available. The other manufacturers keep this close-to-the-vest. I had to develop our whole modeling philosophy from scratch. And I had to learn a lot about tube amps and their design to do that.

So our approach is probably somewhat different than the typical modeler. First of all we take a two-stage approach: preamp and power amp. The preamp modeling aCCounts for the equalization of the various stages and the different nonlinearities present. It has the usual tone-stack simulation and models the location of the tone-stack (pre- or post-distortion). There's also some very special stuff going on in the actual modeling of the tube itself that I can't really talk about.

The power amp modeling is where things get really interesting. A real tube amp is a dynamic beast. When you get to that sweet spot the amp becomes sensitive to the nuances of your playing and feels like an extension of yourself.

Although it requires an enormous amount of computation, we try to replicate this behavior. The Axe-Fx power amp modeling simulates the dynamic behavior of real tube amp. The frequency response changes as you play harder. We even model the "sag" of the power supply and the resulting compression. Unlike most modelers we have a separate "Master Volume" control that allows you to adjust how hard this virtual power amp is driven.

The result is a modeler that has the "feel" of real amp. One that responds to your playing and cleans up if you roll of the volume knob. You can even adjust the amount of sag to your liking. So you can take a Plexi model, for example, which in real-life has a solid-state rectifier and make it feel spongy like it has a tube rectifier.

We also model the effects of the output transformer and all the other subtleties of a real tube power amp. We even model minute details like the snubber cap across the phase inverter. It's painstaking but offers a greater degree of realism.

The other big factor is just simply the quality of the components and of the algorithms. With this much compute power we don't need to skimp on our algorithms. Digital effects have become much maligned recently. The manufacturers are primarily to blame for this. Rampant cost-cutting and overzealous marketers have forced engineers to cut corners on the quality of the components and more importantly on the quality of their algorithms.

For example, I can show you two different ways to implement a chorus algorithm. One of them will require ten times the computational power of the other but sounds much better. I'm sure you can guess which algorithm most products use since it allows them to use a lower-cost processor. And this is a real shame since it has given digital effects a stigma. Analog effects are in vogue now because guitar players CAN hear the difference. Marketers advertise "120 simultaneous effects in one rack space" and then expect the engineers to code that which means they have to use low-quality algorithms.

MGS - Can you give us an overview of the AxeFX and its features?
CC - How much time do you have? LOL. The Axe-Fx is a marriage of our state-of-the-art amp modelling and arguably some of the best effects processing around. In additon you get full control over the routing of the effects, a routable effects loop and sophisticated real-time control.
The firmware for the Axe-Fx was written using an object-oriented approach which allows for two instances of most effects. So you can use two amps, two cabinets, two graphic EQ's, etc. simultaneously. Abundant EQ resources allow you to craft almost any sound you can think of. Lush reverbs with modulated delay lines rival those of high-end studio gear or expensive software plug-ins. Wah-wah, formant filter, chorus, flanger, phaser, rotary simulator, intelligent pitch-shifting, modulated delays, multi-tap delays and more allow you to achieve the sound of a refrigerator-sized rack full of gear in a two-space box that consumes less than 20 watts.
You can control many parameters in real-time either using external controllers (MIDI or rear panel) or internal controllers like LFO's and Envelope Follower.

The Axe-Fx is also eerily quiet with an astonishingly low noise floor. Preset changes are lightning fast. There's also a new delay spillover feature that allows reverb and delay spillover between preset changes.

MGS - Did you dissect any of the Line 6 devices or any others to see what made them tick?
CC - Naturally I've tried nearly all of the modeling products out there. I've always gone away feeling like something is lacking. It almost seems as though they are charicatures of the real thing.

Some I feel are better than others and all have their various strengths and weaknesses. Line 6 certainly dominates the industry and their products are well respected.

I didn't disect any of the devices because nowadays there's little to learn taking one apart. In the old days you could take an amp or effect apart and reverse engineer the schematic for it. Digital devices are really nothing more than specialized computers running custom software.
Myself and others here have done extensive listening comparisons though. And we've measured various parameters of competing products, such as preset change time, noise floor, etc. We've done double-blind testing as well using the Axe-Fx and various products against real amps. This helped us fine-tune the amp models and effects.

MGS - What was the biggest hurdle in bringing the Axe FX to market?
CC - Since I have a lot of experience producing products I had a lot of contacts and resources so making the prototype and the subsequent production units was in fact fairly uneventful. The biggest hurdle right now is marketing. Guitar players are a fickle bunch and tend to reject new technology, especially new digital technology. Also the price is a bit of barrier. Our component costs are high so we need to charge around $1500 for the unit. People will readily spend that on an established brand like Eventide or TC Electronics but are reluctant to risk that on an unknown brand. Perhaps this article will help in that regard.

MGS - Do you feel it is stronger in the studio or live?
CC - I feel it is equally at home in either. I use one (actually two, one for my guitar, one for FOH effects) in my band. I use it through a power amp into a 4x12 cabinet. It sounds great and I get a lot of compliments on my tone. For live use there are all kinds of nifty features like global effects and reverb mix as well as global tone controls. These features allow you to alter the overall sound of the unit to fit the venue. For example, if the room your playing is lively you can turn down the global reverb mix and this will reduce the reverb on all presets.

For small gigs and rehearsals I use it directly into the PA system. It sounds so good that way that lately I've been very tempted to get rid of my power amp and cab. Less stuff to carry around. But a 4x12 on stage just looks so cool.

For studio use it's absolutely killer. You can use it to get great sounds with no additonal processing. Plus you can reamp with it using either analog or digital modes. Several studios are using them outboard just for the effects processing ability.

MGS - Any power amp/speaker combo that is performing well with it for live use?
CC - You can use it with just about any power amp, tube or solid-state. With a tube amp you can defeat the unit's power amp modeling and just use it as a preamp and effects processor. With a solid-state amp you can use the power amp modeling to make the solid-state amp sound like a tube amp.

Pretty much any cabinet will work. Here we take a different philosophy. Many modelers have speaker compensation and leave their cabinet models on. You tell the unit roughly what kind of cabinet your going into and the modeler attempts to compensate for this. In theory then you can make a small 10" speaker sound like a big 4x12" cabinet. In practice it falls way short. There's technical reasons why but I won't bore you with the details.

So we recommend that the user simply turn off the cabinet modeling and choose a cabinet that suits his style. The Axe-Fx then becomes the ultimate collection of vintage and modern amp heads (plus all the great effects).

MGS - Are these being made in the US?
CC - Yes. Currently all manufacturing is done in the US. It increases our costs but someone has to take a stand against the exporting of jobs. I could wax philosophical about the whole global economy thing vs. CEO compensation but this isn't the place.

MGS - Can you run us thru the assembly process and how its put together?
CC- Since we rely on domestic labor the manufacturing had to be streamlined as much as possible to keep costs down. We have the circuit boards manufactured and populated by local contract manufacturers. They have these fancy robotic machines that place components and solder them down. The circuit boards are all surface-mount components. The inside of an Axe-Fx looks more like the inside of a PC than any amp.

We then take the boards and do preliminary testing. The tested boards are then simply placed into a chassis along with a power supply, the display and a few cables. A unit can be built-up in under an hour.

The final step is programming and final test. The units are programmed and tested to meet specifications. Finally they are play tested and then burned in overnight to eliminate the possiblity of any infant mortality failures.

MGS- Have any of the major modeler folks come sniffing around to see what you are up to?
CC - A little. Less than I figured though. I'm sure they know about the product and perhaps even bought one and have taken it apart. As I said before it's very difficult to reverse engineer digital devices nowaday but I wouldn't be surprised if one has been dissected.

MGS - Where can these be heard at? Do you have any plans for major distribution?
CC - Currently we only offer internet sales. We do however offer a 30-day return policy. We're a very small company right now and the internet model works well for us. Naturally we'd like to grow and welcome any distribution partners. We just sent one to the UK for evaluation by a prospective partner.

MGS - How long have you been working on the Axe Fx?
CC - Whew, almost four years of R&D went into it. It contains nearly 40,000 lines of software. Plus there was all kinds of custom computer programs we had to write to measure and evaluate amps and acquire test data. My fiance has been so understanding through all of this and I'd like to thank her for her patience. Some weeks I worked until 2:00 am every night.

MGS - What else do you enjoy doing?
CC - Naturally I love playing the guitar. The electric guitar is the greatest thing to happen to music since the discovery of electricity. I also play racquetball at a competitive level although my knees aren't what they used to be.

I have a three-piece band that's a lot of fun. We're fairly decent when we're not fighting, LOL.
Some of my biggest enjoyments are my pets though. I love cats and although I had a couple die of cancer recently it hasn't stopped me from adopting more. My favorite cat "helps" me write software by stepping all over the keyboard. He makes phone calls too.

MGS - I talked to one of your beta testers and he said the effects inside are world class high end effects. Was that a goal from the get go?
CC - Most definately. I'm an effects junky. I use it to cover up my lack of ability. Therefore I'm critical about the quality of the effects. The unit he has is actually a full production unit. The firmware has been out of beta for a few months now.

The Axe-Fx is a great effects processor. Even if you don't use the amp modeling it makes a great adjunct to an amp or preamp. The routable effects loop allows you to use the "four-cable technique" where you can place some effects before an outboard preamp and some after.

MGS - Where do you feel current modeling falls short and why is yours superior?
CC - I think the biggest weakness in current modeling technology is the cartoonish sound and the artificial feel. The sound has improved in recent products and is less sterile but the feel is still awkward. One manufacturer has addressed the feel issue by using a 12AX7 tube as a miniature power amp with a dummy speaker load. It works fairly well actually and is likely an analog version of what the Axe-Fx does digitally. The Axe-Fx is more sophisticated and since done in software allows us to vary many parameters that wouldn't be possible with a hardware solution.
The strengths of the Axe-Fx are in the level of sophistication and detail in the modeling and the dynamic nature of the algorithms. The dynamic response is what gives the player that feel. When you play a cranked tube amp and hit a power chord the bandwidth is reduced and the chord sounds thick. As the notes decay the amp comes out of saturation and the bandwidth increases allowing the notes to bloom and sing with overtones. Also we model the power supply in great detail. This virtual supply responds like a real amp and sags as more current is demanded from it.

MGS - What are your goals for your company for the next few years?
CC - I'd like to see the company expand into other products. We're investigating a lower-cost version of the Axe-Fx now. Same great sound but with fewer features and only one of each effect. We're also working on porting some of the Axe-Fx code to VST plug-ins. I'm also working on a device that allows me to read cat's minds. So far all that it says is "hungry.. tired... hungry... tired". Must be something wrong with it.

I'd really like to see the Axe-Fx sway the industry as a whole. Digital effects are great when implemented properly. Unfortunately a whole era of crappy digital effects products has really given digital a bad rap. Part of the problem has been the whole shift towards pedals. It's not really economical to put a DSP in a pedal that's just going to do one thing.

The industry needs to come up with a better way to leverage digital technology in a manner that's easier for guitar players to use. Rackmount processors like the Axe-Fx are intimidating to many players yet stomp-boxes have little if any features, control or programmability. There needs to be some new way of getting technology into the guitarists hands.

MGS - Do you think folks will see the reason for the price difference right away say putting it right beside a POD XT pro?
CC - I certainly hope so. Although some probably won't. Many people are motivated more by price than anything else. Boutique products are inherently low-volume and targeted towards discerning consumers.

I could demonstrate the Axe-Fx alongside a Pod XT Pro and show someone all the great features and how much better it sounds but in the end all that matters is the price tag. Some people buy Chevy's and other's buy Jaguars. The XT Pro is a good unit. I own one and although I don't use it many people are very pleased with them. It doesn't have anywhere near the features of an Axe-Fx but then it costs about half the price.

MGS - Anything you would like to add in closing?
CC - I hope this interview convinces some people to try our product but more importantly if you have the means please donate to charity. The world is a brutal place right now and people need help more than ever. Also, if you can, adopt a cat. They make great office assistants and can help with the filing and typing chores.

MGS - I wish you the best of luck with the AxeFX and look forward to trying one someday.
CC - Thank you.