Tube and solid state on a professional recording

[RDK]

I'm new to tube amps and the theory behind it all. I have really been digging deep lately and listening to many different guitar tones on recordings.

I have a friend who is set on using a line 6 pod on all of his stuff in his studio. When I record there I always use one of his old Marshall 50 watt heads. I know I can really tell a difference between my recordings and his. His guitar almost always sounds very bland? Maybe even sometimes dry. I'm pretty sure he runs it straight. No pre amps.

My question is: does this mean I'm developing an ear for this kind of thing? Can you typically notice differences between solid state and tube amps? I know maybe in the studio might be a different story due to production and what not but what about in a live setting? Is it a pretty noticeable difference wether something is tube or not?

[Jazz P Bass]

Can O Worms.
Tubes compress the signal when overdriven.
Solid state will get raspy.
On a clean signal (ie: Jazzy) & at low volumes I think you would be hard pressed to tell the difference.

[teemuk]

Is it a pretty noticeable difference wether something is tube or not?

No. It's not.

What you are hearing is more likely
- differences between two more or less dissimilar amps/cabs. You'd hear this even with only tube amps or only solid-state amps in use.
- differences between two different players, their touch, technique, EQ preferences, perhaps different guitars and pickups too
- differences between two different approaches to recording, e.g. mic placements, mics, mic preamps, perhaps plain directly-in approach and so on.
- and so on.

Too many variables.

Throughout history plenty of professional guitarists have recorded many classic and influental guitar albums with solid-state amps. People "hear" solid-state or tube tone only if it's pointed out to them.

[RDK]

Ok cool. Thanks guys. Any thoughts on the line 6 pod in studio application?

[teemuk]

^Which one?

It's a great tool and several professional musicians (e.g. Jerry Cantrel, The Edge, Meshuggah's guitarists to name a few examples) have used the more "pro" versions of the POD (XT or Pro) in their rigs both live and studio.

[jrfrond]

For the most part, the POD or software-based stuff like Amp Farm, Amplitube, etc. will work in most application for recording. Sometimes guitar tracks are even virtually re-amped using them, even though they may have been recorded with an amp. A lot depends on the engineer too. I never thought I'd hear my own brother, who is a die-hard, old-school engineer with guitar-rock street-cred, say that he doesn't even bother miking amps anymore, in many cases.

[retgaz]

I run an original Marshall JMP 50watt head for live and recording. I've had it for about 30 years now and really know its sound. In the studio I've used POD's for overdubs and bits of double tracking and I could barely tell the difference. The only real difference I could find was that you can't realy do controlled feedback on a pod. For general playing in the studio pods are great, way more flexible than an amp.
Live they suck.

[Steve Conner]

I've had similar experiences, the digital stuff works great for recording and reamping, in fact it can be a lifesaver if you don't have anywhere to crank a real amp and mic it. I remember helping some friends to record an album, for some guitar parts we used a few of my amps mic'd up, and others were added later with Amplitube. The Amplitube ones sounded better. I guess it is possible that my amps and/or mic technique suck. We adjusted the amps to sound good in the room, and they sounded too dark on tape, they didn't have enough fizz and buzz for the punk rock we were doing.

But it's not as gratifying to play live as a tube amp. Many people blame this on latency. I know that is the reason why you can't do controlled feedback, but people also complain that the digital stuff feels dead or doesn't cut through the mix like a tube amp does, and I have no idea why that is or even if it is true.

[kg]

well, i dunno about you tin ears, but *I* can hear a difference in the tracks...

one has no mic bleed and amp hum, and the other does.

[jrfrond]

I have to agree with Steve on this. There's just no substitute for tube amps.

Or is there?

For me, the issue is more digital vs. analog. There have been some crazy-good analog solid-state amps on the market, and continue to be. Tech 21 is a great example, with the SansAmp circuit.

When the Pod was THE hot thing, my friend Andrew Barta, owner and designer at Tech 21 and I sat in his office/lab and compared tubes, Sansamp and modeling on a test rig. As it turns out, the issue is not so much the modeling as it is the incorrect time arrival of harmonics. You are taking a complex analog signal, digitizing and streaming it as serial data to the DSP, and then reassembling it using D/A converters to output parallel data again. Time arrival/phasing of harmonics is what suffers. This is why harmonically-rich modeling patches (e.g. distortion) often sound "wrong", or have odd interval notes fighting/beating with each other that would otherwise be a piece of cake for a pure tube amp.

Tubes are a voltage-based system. Solid-state (analog or digital) is current-based (except for FET's, which STILL don't sound exactly like tubes). Digital is, well.....digital. It's three distinctly different systems that, in an A-B-C comparison, don't perfectly mimic each other. The issue that remains is: how does it sound in context? This question has been asked about a lot of things in this industry: amps, synths, e-drums, etc. ad nauseum. But it's really the only thing that counts.

[Steve Conner]

Digital modelling gear almost universally uses sigma-delta ADCs and DACs. I don't know of any that uses any other kind. These have aggressive digital anti-alias filters that are often accused (mainly by audiophiles in the CD vs. Vinyl debate) of messing up high-frequency transient information. Maybe this has something to do with John's arrival times of harmonics.

But the filters are supposed to be linear phase, which means not disturbing the relative phases of things. And not only that, the accepted model of the human ear is a kind of spectrum analyser, that can't detect the relative phases of the harmonics, just their amplitudes.

I sometimes wonder whether the real problem with modelling amps is that the programmers don't gig them enough, and so don't understand what a good amp for live work has to do. The ZT Club is one digital amp that apparently does work in a live situation, and as far as I know it was designed by an old bearded wizard with lots of tube amp experience. I briefly played one in a guitar store and was impressed enough that I wanted to take it apart.

[retgaz]

For me a lot of the difference is in the response to dynamics in your playing. I play a lot of blues stuff live, where my guitar volume is on 8 or 9 and the amps just on the edge of breaking up. By changing my playing slightly or rolling a tiny bit of volume on I can get from a really clean sound through to a warm sustaining solo. Digital just doesn't do that....yet. I've also found digital stuff doesn't work too well with my collection of trusty pedals.
Like I said in my last post though, digital is great in the studio where a lot of the dynamics get processed out and you're not likely to be playing rhythm and solo parts on the same take.

[kg]

the problem with modeling amps is that they fall apart at high SPL.

that's because their crappy power amps come into the picture!

[jrfrond]

the problem with modeling amps is that they fall apart at high SPL.

that's because their crappy power amps come into the picture!

I tend to agree with this as well. The lower damping factor of typical tube guitar amps makes the amp sound "bigger", as the speaker cone tends to overshoot and ring more. Line 6 did a relatively decent job of countering this with the Spider Valve, and it does sound pretty good, though the staleness of digital modeling still peeks through at high preamp gain settings.

It's the distortion patches generated by digital modeling amps that annoy me more than anything else. When recording at home, I'll use the Pod for amp modeling, but never for distortion. I've got analog stomp boxes that do a much better job.

A fine example of this was last week, when my 15 year-old son, who can play the livin' shit out of guitar, was in a Battle Of The Bands at his high school. Out of four bands, he was the only one of three guitarists using a tube amp, and the OTHER guitarist in his band uses a Line 6 Spider. The modeling amps just got buried in these band settings. Now, of course, it could be just the patches that were being used. Listen, I work a lot around NYC and the surrounding area as a drummer, so I get to hear a lot of different guitar rigs. I've heard modeling rigs that sounded good, and tube rigs that sounded bad. What it really comes down to is, like acoustic drums vs. e-drums, you can't use the same techniques on a modeling amp as you would on a tube amp. The simple aforementioned act of turning down to clean up your sound usually doesn't work in a modeling setting.

[teemuk]

Of course neither's a POD but...



I've seen plenty of people gig with modelling amps and those who understand to dial the tone patches at loud volumes and in a bandmix never have had trouble cutting through and sounding good. Those who do not understand that the patch that sounds good at conversation levels in a 4x4m bedroom falls apart at loud volumes in a crowded bar or practice room always sounded poor.

It's as simple as that whether it's a $100 modelling rig or a $2K modelling rig.

[km6xz]

When a band asks me nicely enough for me to listen them for suggestions, one of the things that often gets suggested is dumping the modeling amp until they learn to develop a style. I find that all the possibilities of decent but not great or interesting characteristics available to them, their time for experimenting with playing style, basic musicianship etc is wasted by not focusing on any style that can be uniquely their own.
I don't know of a guitarist who has made it that did not develop their own characteristic style and sonic signature. Same with vocalists but that is another thread. If commercial success is desired, where a fan base is built over a span of time the musician has to realize that a generic sound or "mistakeability"(being ambiguous enough in style as to be mistaken for anyone else) kills all interest by labels or producers to deal with someone, even if they are technically skilled. The investment needed to promote and develop as act is considered too risky of an investment if the group/artist is easily confused with someone else...another brand so to speak.
Modeling amps get in the way of that.
For a lounge act or cover band where the idea is to mimic sounds of others, a modeling amp is an effective tool. They work with any size club or restaurant, cruise ship or wedding party. For original material, it is death until a style is developed, which may never happen if relying on digital short cuts, that anyone can reproduce.

As far as amp active devices are concerned, when played in the more linear portion of the conduction curves, there really is no inherent sound difference. The fact that amps do use the same sort of topography is more signicifcant. Solid state relies on high levels of negative feedback and as a result have lower distortion and flatter frequency response, and almost always are in some sort of AB class of operation. Tube amps can be found that us Class A or AB, have little feedback.
A well set up amp using solid state and a well set up amp using tubes should not sound much different if levels stay within their most linear portion of their curves. The real difference that people talk about when comparing tube and solid state is what happens to the transfer function when overloaded, in a very non-linear portion of the curves. Tubes overload differently and produce a different harmonic spectra than solid state when overdriven.
In recording, SPL is not so important, but playability is, and tone is so often, when the video is produced the whole studio is lined with double stacks...looks good and is what the fans expect made the sound. More often a practice level amp was used for the actual tone generation since it allows great isolation, fewer audible spurious products(rattling hardware, creaking cabinets etc) and Class A can be used when desired.
I do not record any more but the decades I did seem to be a desired goal when people are trying to get a tone, and what software designers are striving for. What made the great tone on many notable records? Mostly playing technique but also a recording team that was highly experienced with the medium, analog recording systems. A typical session might have 100 years or more of accumulated experience in recording. Budgets were high enough to have a concentration of talent on both sides of the glass that just can't be found today except in a very few super session projects. The reason so many recordings now are less than inspiring is partly due to the rush to record(is it almost free to do so, which means songs are recorded before being finished or anyone passing judgement on them). This means most songs just are not worth any more than what is invested in them....nothing. It has never been easy to write great songs, even the best song writers only create a few really great songs in their career. Before, when it was very expensive to record, and usually done with other people's money, only well vetted songs ever got close to a 24 track Studer. That meant that a goodly proportion of recorded songs were actually pretty good, and audiences responded since the majority of major label releases were profitable, even when base recording budgets were around 5 times what they are today. A lot of old recordings set the stage because audiences did not hear the junk, it was never recorded. Now, everything gets recorded because it is free. We made some great recordings because talented teams were involved whereas it is rare to have more than the band or artist involved. Recording, production and support are different talents than song writing or performing so it is really rare to have a good guitarist also be a good engineer and good producer and good second engineer and maintenance person. All those hats worn by the same person usually results in mediocrity. I was never a player, I just did not have the talent or drive or willing to devote every minute to the craft like the great ones did. But they could not do what I could do for the session, so being part of many great sessions as a contributor to the final was more than enough connection for me. I loved the process of recording in the analog days and really never cared much for computer generated music, and have refused to get involved. After doing one early pro-tools session I decided that the joy was gone, and when back to design and repair, first loves from my pre-teen past.
I still listen to guitarists who want my opinion but seldom hear anything to get me excited, feeling it was done better decades before and there is a staleness and lack of creativity in rock and blues, as if it is always trying to relive another period but just not getting it. I find more interesting things going on in jazz and dance music now and spend more time with both.

[Jazz P Bass]

Nice post.
Then there are the recordings where all the tracks where recorded separately.
You can tell the band wasn't even in the same room at the same time.
Mediocrity abounds in this business.

[km6xz]

Actually almost all recordings, even a lot of "Live Albums" were recorded that way. The only rock era group that recorded live....in addition to OD's is Santana. It was normal to have 120 mics up being mixed live on those.
There was a well known live album that was reviewed as " capturing the essence of xxxxx like no studio album could" which of course had only the crowd noise left from the original field recordings, everything else pieced together recreated one track at a time in the studio.
Even some well known jazz albums were recorded that way. In the early 70s when independent producers come onto the scene, there was a trend towards highly isolated tracks, sometimes with bass and drums recorded together but with the drummer in a drum cone-like structure that absorbed a great deal of the sound from escaping into the rest of the studio room where other instruments might be playing. We used live echo chambers, echo plates and by the late 70's EMT digital reverbs and still later Lexicon to recreate what was lost in the highly damped rooms. We only had 16 or 24 tracks to work with so track management was key to have enough towards the production for a number of tracks for vocals where were usually pieced together during comps of OD's and full tracks. Later, synchronizers were available so we could slave together 2 or 3 24 track Studer's or Ampex's. Mix down was usually done to 2 or 4 track Ampex ATR 102's or 104 mastering decks. The goal was to make it all sound as if it was done all at once. The gear was really expensive and needed daily maintenance. My studio has 3 24 track studios and 6 iso booths, and 1 large echo chamber, a 1/2 dozen EMT echo plates and it was a full time service workload to keep everything calibrated, repaired and PM's. But the 4 full time techs plus me when not recording, were able to prevent any downtime for years at time.
There were very few full album studios, (we never did demos and only a couple soundtracks, one was Back to the Future with Huey Lewis and the News which produced a hit "Power of Love"), and hundreds of full time professional demo studios which where busy. Demo studios had a hard time cracking into the album world, there was a clear demarcation between them but they did fine since there were at least 10 3-5 song demos at $3k-10k(paid for by the labels) for every album recorded. A bygone era.
The well done albums sounded good and organic and still sound good, the same way a well directed, edited and filmed movie looks realistic.

[MWJB]

Jazz P Bass wrote: "Then there are the recordings where all the tracks where recorded separately.
You can tell the band wasn't even in the same room at the same time.
Mediocrity abounds in this business."

By the same token there are lots of tracks/albums recorded today by small to medium level studios where everyone was recorded at the same time, "all on the floor, live to tape, no overdubs, no booths, y'know just like the old days..."(well, no not really), but the guitarist needs "this" kind of delay on his guitar, bass might want a reverb, vocals get something different again...the result is one person sounds like they're in a tiny tin shed, someone else sounds like they're down a well 10yards away and someone else inevitably sounds like they are right in your earhole. They were all in the room together, but it really doesn't sound like it at the end of the day...partly I suppose because even the entry level budget studios have a multitude of options regarding effects, but also because most musicians fancy themselves as some "knowledgeable source" on engineering recordings, usually based on unsubstantiated folk tales bandied about over a beer after gigs & rehearsals..."Yeah, I want that (insert label) echo, that (insert artist) got on (insert song)", errrm, well that one was actually recorded dry!? OK rant over ;-)

Tell a "generic" tube amp from a "generic" SS amp on a recording? No hope.

[Steve Conner]

The best effort I know in this respect is a local blues band who recorded all together clustered around a single mic in a garage, in mono, for maximum old-school cred. I have the album and it actually sounds great, it's the only thing by a local band that I've ever played more than once.

When I recorded with my old band, we used to record the bass and drums together in the same room, but with the bass DI'd so it wouldn't get into the drum mics, and the drummer and me wearing headphones so we could hear it. The rest of the band played and sang along in the control room, and this was recorded as a guide. We concentrated on getting the drums right, because everything else could easily be replaced later.

Then once that was done, everyone else took turns to overdub their parts, a process that could take weeks since everyone had day jobs, and could happen anywhere because we had a portable Pro Tools setup. But the originally recorded guide track held things together.

Our recordings were fairly mediocre and mistakable.

[MWJB]

I know a guy who did similar, recorded guys straight to a hand held minidisc player, great musicians and performances, hours spent positioning things & people...a few "lost days" in the process, but the final result definitely had charm & character....I listen to that a fair bit too.

But here, "who recorded all together clustered around a single mic in a garage, in mono, for maximum old-school cred", I think "Oldye Schoole" - as in "aah, yes, those Oldye Worldye blues bands with their Cor Anglais, recorders & harpsichords, recorded straight to pies made of Bison's earwax" ;-) - might be more appropriate, unless we're talking well pre rock'n'roll era? Multitracking & overdubbing in use from the 30's, close micing from '50, simultaneous multitracking from '51, 8 track recorder from '54, stereo recording from '59....? OK, so not eveyone who recorded at that time had access to all these innovations, but they were technologies of the day.

[Steve Conner]

"aah, yes, those Oldye Worldye blues bands with their Cor Anglais, recorders & harpsichords, recorded straight to pies made of Bison's earwax" ;-)

Running at 78rpm of course I heard a news item on Radio 4 this morning about a band who were cutting their own 78s. But I bet even that isn't as warm and organic as a bison earwax pie.

Do you know what the Beano album was recorded on? I guess it was done at Abbey Road, so they'd have had the latest gear.

[MWJB]

Blues Breakers W/Eric Clapton was recorded at Decca studios W Hampstead, produced by Mike Vernon. Even in the 60's Abbey Road only had 4 track recorders, but they were very proficient at over-dubbing. Not that "4 track" meant they were low tech, Mowtown & Phil Specter were apparently using 3 track at the time.

[kg]

i see similar effects in many different artistic media which have been "facilitated" by gear and equipment: music certainly is one, but also photography, another passion of mine.

the artist begins to be so dependent on the tools that those tools begin to become more of an impediment rather than a help.

ultimately, it's fingers on strings in the case of a guitarist. if that part has a bit of magic in it, it'll likely be a "good take." if the guitarist is instead obsessing about diddling knobs, and getting the sound "just right," and in general being distracted from actually PLAYING, then it'll suck.

compositional skills and conveying a message have taken a back seat to endless debate about tone, which digital modeling amp patch sounds the most "realistic," etc.

i know all too many photographers fixated on getting the newest camera bodies, the most expensive lenses, the biggest lighting setups--and they turn out purely mediocre photos. too much mental energy on the "stuff" and not enough on what's actually in the frame of the viewfinder. once you press that shutter, that's the only thing that matters. the sharpest lens in the world won't make that mundane picture of the pile of dog shit in your back yard look any better.

again, compositional skills and conveying a message have taken a back seat to endless debate about sharpness, dynamic range, pixel noise, nikon vs. canon, etc.

i guess what i'm trying to say in a very long-winded way is that we seem all too willing to make things complicated, when the simple would still net 90% of the "quality" of result, yet would be 90% easier to navigate. having 300 different amp patches doesn't mean anything if you can't even play one. i've limited myself to a three channel amp for a very, very long time, because i STILL don't know how to play it! lol

[Steve Conner]

having 300 different amp patches doesn't mean anything if you can't even play one.

Yes, it does! Having lots of controls to play with helps the guitarist to forget that he sucks. Likewise with the pixel-peepers in photography, you can have endless fun admiring the technical quality of your pictures of utterly dull subjects.

The fundamental question is about content vs. presentation, medium vs. message, whether you personally have anything to say in the medium. If you don't, you can still have fun playing with the technology, but don't be surprised if nobody is interested in your output.

So when shopping for gear (or constructing it for that matter) it helps to be sure of your goals, are you trying to make a work of art to engage your fellow human beings, or just looking for more toys?

My own yardstick on music technology is that if I can't remember how a feature works after 3 beers, I don't need it.

[kg]

the only caveat i want to add is that "new stuff" has a sort of secondary benefit... one that i can't help but fall victim to myself, despite my attempts to resist...

it can make it more fun to play!

getting a new lens for your camera can help bust you out of a rut, just like getting a new stomp box can do the same for your picking. it's FUN to investigate how something works, what its strengths are, and its weaknesses.

so that end, if getting a pod or line 6 or whatever makes you want to play the guitar more, then it's a "good thing." even if you never end up using it to record or whatever. sometimes (most of the time?) inspiration is the short commodity, and every little bit helps.

[Ronsonic]

Listening to the difference between modeling and "real" guitar tones isn't all that revealing to me. The technology is good and holds up better than I predicted. When the Pod first came out I was extremely skeptical - you know how in movies you see a special effect onscreen and it just amazes, then two years later you see it again, but now all the wires show. That's what I was expecting. Or listen to the synths on something like Robert Plant's Now and Zen, they were good, but now you can hear each bit. Good on Line6 their technology has held up much better than that.

What they haven't gotten right is the gain curve. What happens when you roll up the volume on the guitar to go from clean to sustained. My real amps, tube and SS can do this gracefully and I have distinct clean, compressed and distorted tones and a gradient in between. With modelers I need a guitar on 10 patch, a 9 patch, an 8 patch and so on for each amp model to get that dialed in and sounding right to me. Of course a lot of guys don't touch the guitar knobs so it's perfect.

[Steve Conner]

What they haven't gotten right is the gain curve. What happens when you roll up the volume on the guitar to go from clean to sustained. My real amps, tube and SS can do this gracefully

That's interesting, it kind of agrees with what other people have been saying. I wonder whether there is something in the physics (math, even) of modelling amps that forbids it?

Maybe getting the gain curve right needs a huge amount of DSP power and a NASA grade A/D converter.

I know that 16 bits aren't enough for recording situations. When you record raw tracks to your DAW with the intention of applying compression later, and leave headroom to allow for those unexpected peaks, it eats right into the available bit depth. Every 6dB of headroom you leave, and compression you add, you lose one bit. If you started out with 16, it is easy to end up with only 12, but the goal is to have 16 full bits of information going onto your master mix. So you can really notice a difference when you go to 24 bits.

Rolling off the guitar volume will reduce the usable number of bits in a modelling amp in exactly the same way. I don't know how many bits are in the various modelling amps, or if they use analog dither.

Or maybe the programmers at Line6 just don't touch the guitar knobs?

[km6xz]

Steve, it has to do with the nonlinear response to the activity of playing, the continuous range of input control and the nature of modeling events that are not fully understood. The complexity of interaction between wood, strings, magnets, room acoustics, speaker and amp transfer function and much more are modeled after capturing one point in spectrum of complexity. Than another point is captured and any number for creating an overall model of the total combined output. That makes discrete steps in the model that ignores the elementary contributions by the parts that make up the live playing and listening experience. A very good model can be created on any one of those points but how to transition from one output model to the next when a player slightly alters pressure, attack, damping of the body with arm pressure, turning at an angle to the speaker and back again....all things that have a strong impact of the results at any given instant.

Same thing happened with keyboards. Piano players had to figure out ways of transitioning to instruments that lost a great deal of the playability they grew up with in a mechanical key system, sound board and continuously variable response to input change. They changed their playing and their expectations of what could be played and communicated. Nuance was out, tones and sounds were in.
The people who have succeeded in generating popular acceptance of their modelling amp usage have two things going for them, their adapting to a different expectation of expression and an audience that does not care. New sounds have been adopted as fully acceptable replacements for different instrument sounds. To a teen today, a beat box IS the rythym section and live drums, bass, percussion is a weak impersonation of a beat box. Someone who grew up with live drummers will always feel a beat box is an impersonation of a drummer behind a physical kit. The former class of audience dominates music sales so will be all that survives in music of the beginning 21st century by archeologists in 200 years future. To those of that era, the very definition of some sounds will be a synthesized product of a programmer, not a musician.

One problem for creativity is that the greater options imagined by buyers of equipment conceals the fact that they are limited to creations that are pre-engineered into the device. Sort of the pencil versus word processor world view. A designer of a pencil has no idea or concern what the device is used for, possibly for writing but it can be used for an infinite variety of purposes, including one recently I employed, breaking one off in an enlarged and worn screw hole in a door frame, and screwing the screw in as tight as new when the door was installed 150 years ago. A wrote process can only do what was explicitly designed into it. If its designer fails to be imaginative, the user is limited. But the unimaginative user can bypass to a large extent, grammar, spelling and penmanship training.

As for my own listening, I doubt I have ever heard an accomplished musician who had something to say, and expressed it well who was dependent on a modeled anything. There might be some but I never heard them. They are great crutches for unimaginative, or unpracticed players, however and get more people noodling around and buying gear which helps keep the costs down for musicians we would enjoy listening to.

[Steve Conner]

So Stan, would you agree with my viewpoint here? scopeblog » Less is More: Pay More, Get Less

I hear what you are saying about just capturing single points in the continuum of how an analog amp behaves. If I made a modelling amp, I would want to start with an equation that modelled a vacuum tube over its whole relevant operating range, and a mathematical proof that the equation had no audible discontinuities. Then string it up into a real-time thing that is more or less a Spice simulator.

I don't think that is feasible with consumer-level DSP technology just now, but the stuff is getting more powerful every day.

Oh, and a little module to simulate tube microphonics and the crash you get when you kick a spring reverb.

[teemuk]

I don't know where these "doesn't clean up with volume knob", "doesn't interact with my playing" -ideas come from because I've been hearing plenty of people saying exact opposite and the youtube video I posted here pretty much demonstrates that either of those claims holds no water with a good modelling unit. Then again, I've also heard people saying that you need to install potentiometer brand and style x to your Trainwreck or whatever myth-ridden amp or otherwise it doesn't clean up with your volume knob and interact just right... So I'm willing to believe that a large part of this is in the head of the guy holding the guitar.

A tip: reduce the compression and gain that those modeling amp patches usually have way too much. Tweak the patch sound clean at clean volume settings of your guitar and then it automatically overdrives when you up the volume. Also, learn to control your pick attack. It really isn't rocket science.

[kg]

So Stan, would you agree with my viewpoint here? scopeblog » Less is More: Pay More, Get Less

I hear what you are saying about just capturing single points in the continuum of how an analog amp behaves. If I made a modelling amp, I would want to start with an equation that modelled a vacuum tube over its whole relevant operating range, and a mathematical proof that the equation had no audible discontinuities. Then string it up into a real-time thing that is more or less a Spice simulator.

I don't think that is feasible with consumer-level DSP technology just now, but the stuff is getting more powerful every day.

Oh, and a little module to simulate tube microphonics and the crash you get when you kick a spring reverb.

i think you're on to something.

rather than trying to model the whole amp, as a black box, model components (or at least groups of components).

[km6xz]

Sure, a dynamically varying simulator for the active sound generator would do it. There is the problem, the simple part is amplifying devices but all the others really a problem: wood, glue, body mass/damping, figure pressure, acceleration, string characteristics and all the things that play together in an analog system of creating a spectrum that the modeling amps thus far ignore. They focus on the transfer function of the amp. But the amp being modeled has a difficult to model interaction with all the above mentioned variables.
At a single gain level the identical harmonic spectra of any amp by digital modeling methods and even analog methods. That is the "easy" part. We still can't model the properties of a guitar being played by a human.

[Steve Conner]

That is the "easy" part. We still can't model the properties of a guitar being played by a human.

Who said we had to, though? This thread is about modelling amps.

They focus on the transfer function of the amp. But the amp being modeled has a difficult to model interaction with all the above mentioned variables.

Sure, but it must be possible to quantify the amp's interaction as a transfer function, albeit in the full sense of an arbitrary function that can be non-linear and stateful, which is a far cry from the linear transfer function theory we learnt in college.

If you argue otherwise, you imply that the amp is accepting some other input besides the jack on the front, or maybe somehow talking back to the guitar. Of course the amp does talk back to the guitar, see the controlled feedback vs. latency issue raised earlier.

[km6xz]

The amp is talking back to the guitar in any high gain situation, put the amp in an iso booth and see how different the amp and guitar interact. The problem is we do not know how to model the input signal, otherwise, by approaching it only from the amp side and ignoring their interaction, the modeling of response of the amp to the characteristics of player/guitar combination will neglect to primary goal of creating a system that mimics the playing characteristics and response of known amps and playing styles. But this is all a short term transition, eventually a new generation of players will only know modeling amps and string synth devices and so will not want old playing styles to be reproduced. How many people playing keyboards now care if it emulates the playing response of a piano? In 10 years few people getting into guitar will bother with non-programmable guitar(the modeling amp will not be needed since it is cheaper to build the tone generators into the guitar and use wireless links to the pa system). Old timers will still tinker with "old wood" or vacuum bottles but they will die off soon enough. In years past there was an effort to simulate tape machines when creating the operation and sound of old analog tape. That was just 15 years ago and now the concept is not bothered with and is not even remembered by 90% of recordists today. CD players are still designed to simulate manual manipulation of vinyl records but that is steadily being replaced by computer based DJ program generators which do away with the idea of manipulating anything physical. So this whole issue of modeling is to temporarily appease those who remember the old methods of playing but they will soon be gone.