I'd like digital stomp boxes to stay digital

Why isn't there a standard digital connection between stomboxes? Let's say you've come by some money and bought a Strymon Lex and a TC electronic Flashback and an Evenetide Space and you hook them up to your pedalboard. Each and every one of these pedals convert your signal from analog to digital and back to analog again. This really just need to be done once, preferably by a boutique made stand alone unit :wink:

Seriously I think that it's weird that no has thought of this. I can only see advantages if you could connect all of your digital boxes and bypass the ad/da-converters. It's like building your own modular multi-fx.

I'm certainly no engineer and I could be totally wrong about this. What's your thoughts?

I understand what you are saying, but I've been drinking

Why not just stick to one type of pedal? Wouldn't that be easier...

Because, the main difference between analog and digital signals is that an analog signal is continuous and a digital signal is made up of individual points. At least that's my understanding of it.

Can a digital signal be converted to analog? Not sure. Might be possible the other way around, but I thought analog was sweeter sounding to the discerning ear...

When the pedals are off they pass your straight, or analog, signal.

Also, a lot of time based effects pass the dry signal straight through and only the delays are digital.

Call me old fashioned, but the last thing I want is for the current induced by strings vibrating in a magnetic field to be digitized on its way to being amplified by electrons moving through a vacuum tube. Something about that just don't seem right! :shock:

What T-Funk said

Can a digital signal be converted to analog?

Of course it can. What do you think the bits on a CD or in an iPod become on their way to a speaker?

FWIW - I'm on beer #2, but I still have my wits about me! :mrgreen:

In a word, $$$.


Price any digital mixer against an analog.



.

What would happen if you wanted to put an analog pedal in between? Perhaps a distortion box, or an analog wah. Or EQ, boost pedal, compressor, etc... I understand what you are saying, and there always will be signal degradation when you have multiple A/D conversions going on in each pedal. If you want to get rid of that, use a pure digital multi-effect unit.

I personally prefer analog stuff. Not so much for the sound, but for the longevity and tweakability (I'm an electrical engineer, so I mess with them a lot). You can't do that to digital stuff. That said, digital reverb and delay is a must in my book. And I have a digital wah.

I get it...there are VASTLY differing qualities of analog-digital-analog conversion circuits out there, and the debate as to repeated conversions, especially with very low quality ADDA events, is supported. Most higher end studios (that I've worked) tend to avoid the practice of switching between the two worlds more than absolutely necessary.

Would be nice if digital pedal guys would integrate digital IO (S/PDIF, whatever) into their products, but that would likely bring their costs up substantially, not a wise choice to the marketing people.

What would happen if you wanted to put an analog pedal in between? Perhaps a distortion box, or an analog wah. Or EQ, boost pedal, compressor, etc...


+1 That is really the best reason. Call it "marketing" if you will, but more accurately it is "understanding your market". Guitar players use a wide array of analog and digital pedals, and analog serves as the lowest common denominator. It works to interconnect everything.

I understand what you are saying, and there always will be signal degradation when you have multiple A/D conversions going on in each pedal. If you want to get rid of that, use a pure digital multi-effect unit.


Yes, multiple D/A -> A/D conversions will introduce degradation, but in practical terms with commercial implementations it's probably not a huge deal for guitar. Electric guitar has very limited bandwidth and is frequently played with much deliberately introduced distortion, both of which will reduce or mask the degradation considerably.

One could conceivably use a commercial standard like S/PDIF to do pure digital-to-digital connections, but it would add cost and confusion for many users, and has the potential to open it's own can of worms. If you were designing digital effects, an integrated DSP unit makes a lot more sense.

in practical terms with commercial implementations it's probably not a huge deal for guitar

This is precisely what is important.

I'm taking an advanced signal processing course right now - we're covering everything, not just the audio part of the spectrum.

The more important aspect with most things involving this IMO is the sampling rate. Fortunately, that was ironed out by Claude Shannon (building on the works of Nyquist and others) many decades ago. And yes - we are talking signal integrity, because he was the first to develop a practical means for communication over telephone wires with an "error rate" of zero.

...So, this was a "digital solution to an analog problem," and it is hardly cutting edge any longer. There just isn't that much material in the audible spectrum, especially with electric guitar, which indeed has a nominally higher amount of harmonic distortion, even when we think the signal is clean.

But there is hardly any kind of standardization with any processing of your signal, whether it be digital or analog. Analog circuits can all have widely different bandwidths before they clip. Different types of power supplies can hamper the signal. Many effects actually have "incorrect" portions to their design. But we've actually come to embrace many of these "broken rule" designs as well.

If you take any fraction of guitar players and asked about gear standardization, you would have as many against something as for it. Les Paul argued the merits of low impedance pickup design, but it wasn't enough to make Gibson put something with such a design in their guitars, let alone the ones with LP's name on them! This can apply to almost anything with guitars as well - how would you "standardize" choice of magnets, tonewoods, body thickness, scale length, fretboard radius...

As long as your combination of pieces works together, that is probably all that matters. Since Company A might make the best ____ effect and Company B might make the best ____ effect, why not just go with the best, and not concern yourself with the differences?

I would disagree...in a world in which we concern ourselves with things like which battery to use (??!!), which cord has the least effect on sound, etc, ADDA is a HUGE part of the sound (at least to my ears)... I would rather hear nails on a chalkboard than bad or badly implemented ADDA.

here's my take, and you can take or leave it: digital per se is not the enemy, but the process of getting in and out of it is the enemy. Society in general, and musicians specifically have just come to accept $.50 worth of conversion circuitry. Choose a DI, plug your guitar chain into a Behringer ADA8000 thru software chorus and delay...then plug the same chain into an Apogee, SSL, newer Digi, Lynx, or whoever conversion platform and listen to the same software effects.

The evidence is right there....IMO, everything matters

I hate to repeat myself....but all ad/da theory aside, wouldn't the more practical reason be that these effects pass an analog dry signal? Since the basic signal is never digital to begin with, how could the effects be hooked up digitally?


And as Wireline points out - if you do really want all digital processing, there are ways to do it.

I hate to repeat myself....but all ad/da theory aside, wouldn't the more practical reason be that these effects pass an analog dry signal? Since the basic signal is never digital to begin with, how could the effects be hooked up digitally?

There is no reason to pass an analog dry signal. The "dry" signal could just as easily be digital with no operations on the signal. It would still be sampled, of course, but then most analog pedals have buffer circuitry and aren't "true bypass" either. It would still be dry.

The basic signal is converted into the digital domain at the input of the effect. The issue of discussion here seems to be, simply, when should we convert back to analog: after the individual pedal or after an entire pedal chain? Transferring the signal digitally from one pedal to the next would frankly be easier than converting through analog at each stage from a technical standpoint.

I imagine that the way that a pure digital pedal board would be implemented would be to have an A/D pedal that would be the first pedal in the chain, followed by the effects, followed by a D/A pedal at the end. Essentially a multi-effect unit without the convenience of having a multi-effect unit.

Many effects actually have "incorrect" portions to their design.

Now ain't that the truth.

Do you feel, that stompbox sucks tone? Change it. Otherwise, just play. Any signal processor changes signal, digital or analog. I know, that is pretty pathetic, but think about tone, note about digital vs analog things.

Do you feel, that stompbox sucks tone? Change it. Otherwise, just play. Any signal processor changes signal, digital or analog. I know, that is pretty pathetic, but think about tone, note about digital vs analog things.

No I mainy use analog stomp boxes with the exception of a TC Flashback delay. I was just wondering why digital stomp box makers don't go digital all the way. For me it would make more sense. If you use a digital connection you can also as I understand it, send more than just sound data. You could for example make a control unit for your boxes to change presets on the fly etc and really use the processing power of these units. This however calls for a standard of data transfer.

As it is today I hesitate to go digital with the exception of delay because I feel that digital boxes don't add that much, it's still a single sound stomp box.

I must say that I'm in awe of your knowledge about these things. Thanks for great answers.

If you like to use many digital effects, just buy Line6 M-9.

For new standard, many companies should supply new universal type of data transmission between pedals. It would be very hard. If only one brand would do it, there is no reason for that, they can just create multi-fx (like Line6 do).
Also, pedals uses specific DSP or IC, which has certain topology and can not be connected to another digital source etc.
Also, many pedals processed only wet signal and direct signal stays analog, but to feed all signal to another device in digital format, it should be totally digital.
So, it seems like that way create more problems, then resolves.
Actually good designed digital pedal with analog dry path, preserves signal better, then cheap analog pedal with crappy buffers. So, it's not about digital/analog. It's more about quality.
Also, I should note, that BBD devices (delays, choruses, flangers) acts slightly like A/D transform. They also quantize signal. But signal loses in that case described like "unique sound".
And finally, one of the benefit of digital devices, is, that you can do alot sounds in one little box with one DSP, so no need to make things harder with cascading devices threw new connectors etc.

P.S. Sorry for my English. It's pretty hard to describe such terms...

The basic signal is converted into the digital domain at the input of the effect. The issue of discussion here seems to be, simply, when should we convert back to analog: after the individual pedal or after an entire pedal chain? Transferring the signal digitally from one pedal to the next would frankly be easier than converting through analog at each stage from a technical standpoint.

This is where you are essentially making assumptions that could cause problems (in regards to standardization).

Some digital effect designers will argue different sampling rates, either because of processor cost, processor speed, or something that could be processor-specific, if they aren't using off-the-shelf DSP.

...So even though you'd be keeping things as zeroes and ones, you'd still have different sampling rates. Depending on which boxes use a lower sampling rate, the downsampling will most certainly cause aliasing. It might sound good (and be partially intentional), but that is a huge guess.

If you expect these manufacturers to standardize the bitrate, they might as well just write software for pc's, or some other little portable gizmo with sufficient processing power (translation - rack unit).

This also is nothing new - as digital recording technologies rose and fell, there were big arguments about a standard bitrate. Remember Sony's failed digital magnetic disk offering prior to recordable CD's? The sampling rate was not 44.1. And other technologies like ADAT were different as well, IIRC. It created a huge mess with aliasing/artifacts/etc. as folks tried to link those boxes up in the digital realm.

So the best you might be able to hope for is digital ports that could be adapted together, with published bitrates. You could then chain everything up with descending sampling rates, and hope for the best.

If there are companies investing big money in proprietary processors for their pedals, they aren't going to be very enthusiastic about moving to some sort of standardization. They all believe they are doing it better than the competition.

This thread is probably already dead but...
Short answer to orig question is - yes it can be done.

It would add cost to already expensive units and would most likely require some sort of standardisation or further do-dad to work.

Essentially all of these digital boxes are little computers. What you are suggesting is just hooking them up at the digital level vs the audio signal level. But once you do that you may ask yourself -Why not just hookup 1 computer to run all of the different effects? Its a far more sensible solution no? No signal or data loss during signal transfer from box to box...

I think the real question is: What sets the one trick pony digital effects apart from the multi-effect ones?

There is no reason to pass an analog dry signal. The "dry" signal could just as easily be digital with no operations on the signal. It would still be sampled, of course, but then most analog pedals have buffer circuitry and aren't "true bypass" either. It would still be dry.

The basic signal is converted into the digital domain at the input of the effect. The issue of discussion here seems to be, simply, when should we convert back to analog: after the individual pedal or after an entire pedal chain? Transferring the signal digitally from one pedal to the next would frankly be easier than converting through analog at each stage from a technical standpoint.

I imagine that the way that a pure digital pedal board would be implemented would be to have an A/D pedal that would be the first pedal in the chain, followed by the effects, followed by a D/A pedal at the end. Essentially a multi-effect unit without the convenience of having a multi-effect unit.

Whether the dry signal should or shouldn't go through a A/D conversion may be worthy of discussion, but the point is that most pedals (TC, Strymon, etc.) don't do that. Regardless of buffers or true bypass (as most higher end pedals are), it's still the analog signal passing through.

And when the effect is off, why convert the signal to digital and then back to analog at all?

As JesterR pointed out, if you want all digital, get a Line 6, or AxeFX, or something like that and program sounds to your heart's content.

And when the effect is off, why convert the signal to digital and then back to analog at all?


Because, in an all digital signal path, that is what you would do. This is just the solution to a problem that someone else asked about. The dry signal does not HAVE to be analog is all that I'm saying.

Because, in an all digital signal path, that is what you would do. This is just the solution to a problem that someone else asked about. The dry signal does not HAVE to be analog is all that I'm saying.

I'm not trying to be argumentative here, I was just taking the original post literally, responding to: "Each and every one of these pedals convert your signal from analog to digital and back to analog again" The pedals he named don't convert the signal to digital, only the effect is digital.

I get what you're saying and I wouldn't doubt that we'll see something like this soon, but as 11guage pointed out, all the companies would have to agree to a standard.

What I could see is a company like TC Electronics doing something like this, but then you'll have to get all TC pedals so they could be connected to each other.

Already been done. It's called a multifx.

Last night I decided to put the only two digital pedals in my analog pedal board in a true bypass loop,a Boss DD-5 and RV-5.The difference with these in or out of my chain was pretty miniscule,just barely noticable, and I guarantee you that nobody at a gig would be able to detect even a slight difference.:neutral:IMO anyway.

but as 11guage pointed out, all the companies would have to agree to a standard.

It's just not going to happen with a stompbox, or a digital effect that should cost no more than $200 is going to end up at a much higher price.

The companies have taken divergent methods with stomp effects because the trick is to keep the price down, and the pedal size down. That means whatever is the most financially attractive alternative to do that.

If you want "digital convergence," then get a laptop and any software/plugins that these companies offer. Then your pedalboard will only consist of a midi device and an expression pedal or three.

And while we are throwing around DSP, it might be good to remember that we might be mixing our metaphors. There are a lot of digital delay pedals that do some crude tricks in the analog domain, most notably adding modulation to delay. It is a lot easier to just design something around an off-the-shelf PT2399 or Belton brick and add a "recipe" around it. Simulated tape echo, spring reverb...

Thank you all again for great answers. This forum is a fountain of knowledge. I was just curious on this subject matter. The technical aspects of this is way beyond my horizon.

I haven't and probably won't ever use a multi fx or a rack unit even if I can see the pros of using it.

I'm satisfied so let this thread go to its well deserved eternal rest.

The technical aspects of this is way beyond my horizon.

That's fine - the more important thing is your curiosity, IMO. Even if there might be facets to any given thing that you didn't think about, it's never ever a loss.

If anything, when I come to a sort of "dead end" with certain discoveries, I find that I just approach things from a tangent at that point.

And the absolute tech details really are just a framework, IMO. Another more important aspect is how technology is used, even if it is simply being cleverly re-used.

I remember about a decade ago when folks started asking about reverb pedals, as in spring reverb pedals. There was the EHX Holy Grail, one with a Hawaiian name that I don't even remember, and that was about it. Now they are numerous. There was a point when someone might have a Dan Echo or the Ibanez SoundTank echo that I can't recall the name of - and some folks just had them because they didn't have the bones for a proper analog delay. And - everyone was dreaming about an actual tape echo machine, as impractical as that was.

I remember being relegated to grafting Lexicon and Alesis units into my rig, because I liked what they did better than many pedals. It was far from elegant, but it worked. I really liked the 'verbs, delays, etc. on the old Lexicon units in particular. With a super clean tube amp, you could get some mind blowing sounds. With a pair of amps, you could push a stereo signal around that was neat, but again just not practical.

It's funny that I figured out that I just don't cop any of the rigs that I envy that other guitarists use, whether they are local guys or big time heroes. I think I've realized that the better players tend to graft together an odd rig of older and newer pieces, some stuff being orthodox or mainstream, others never really being intended for electric guitar use at all. Remember the tape player that Ritchie Blackmore used? Much more important than all the tweaks to his Marshall, at the end of the day. They tried to replicate it with no success, which almost seems humorous. So much of this stuff is elusive, but that is because it tends to be so subjective.

I've had to personally do a big diversion from a lot of the digital technologies, but I am revisiting almost all of them. Despite learning everything about DSP on the programming level (as we speak), I have much to learn in the ways of application. I don't want to just re-hash what Roland or Line 6 has already done. What's the point of that? That is why I mentioned the laptop w/midi boxes setup. I know it's impractical for probably many folks here, but it's one viable method, if you put the time in.

Probably not everyone's cup of tea, but I got Porcupine Tree's The Incident shortly after it came out. There are a lot of either underwhelming or "just wacky" guitar textures on it, but there are some mind blowing ones as well, and almost no amps or stomps were used while recording it. Some of the best guitar tones are very mildly overdriven sounds - lots of harmonics with a good feeling of speakers moving in a cabinet...and yet it's not the case. If Steven Wilson has been entrusted by King Crimson to handle re-mixing their back catalog at the tender age of 44/45, he must have a knack for using technology to get good sounds.

While I am personally a bit of a luddite with guitar tech at times, it's the guys that aren't afraid to try the new tech stuff that really impress me. Anyone can come out with another variation on a 5E3, Tube Screamer, or Celestion/Jensen-voiced speaker. That's fine, but how many different shades of similarity do we need? How many plexi or Dumble amp sim devices are enough?

It is really cool that finally some 'verb and delay effects that are primarily non-analog are really being accepted as very usable tools.

So keep being curious, even if most of the in-depth stuff eludes you. I think it will always ultimately be a positive thing.