What creates a bass amp's "voicing"?

[agedhorse]

I'm not being a smart ass here. Please Name them.

Just about every single solid state and hybrid bass amp ever built. The audio circuitry is completely transformerless.

In pro audio, the use of audio transformers was used historically for isolation between pieces of equipment located some distance apart. This was necessary to reduce the effects of ground loops and noise pick-up, but when high quality active balanced line drivers and differential input circuitry became practical we saw the end of transformers used for coupling.

There are some special cases where transformers are a better choice (high common mode voltages are one such situation) but their drawbacks must be considered in context of the problems they are being asked to solve.

I have designed both kinds of circuits, but most often transformerless wins out.

 

[Al Kraft]

I'm not being a smart ass here. Please Name them.

Baxandall EQ, Fender tone stack, Bob Gallien's GK tone stack and GIVE circuitry, etc. come to mind for me. In fact I would add the Tone Hammer gain and drive circuit design with their interactive nature, as well as the voicing control on the new Subway D-800/800+. as examples of "transformer-less circuits" that play a critical role in an amp's voice.

 

[Munjibunga]

But, can most amps, with proper EQ'ing be made to sound like any other amp?

If not, which is one amp whose voicing could not be duplicated?

I don't think so. Some are better at it than others.

 

[TrevorOfDoom]

Here's a question for everyone .
What is the most transparent head and cab one can buy?

Without a doubt, Quilter Bass Block 800 (measures frequency flat) and a fEarful (any of 'em).

 

[Nic.]

But, can most amps, with proper EQ'ing be made to sound like any other amp?

If not, which is one amp whose voicing could not be duplicated?

IMO the easiest way to understand this is like this: EQ cuts or boosts the same amount all the time, but tone/voicing/etc cuts or boosts different amounts depending on the input. So for example maybe a particular amp gets brighter the more you dig in, which can't be simulated with a treble boost.

 

[beans-on-toast]

That does make since to me. especially in a live setting. sometimes in home recording im striving for a cleaner sound . perhaps direct in from bass to computer ?

I've done that.

Much of the harmonic richness that a good preamp such as a Neve adds, comes from the transformers and the class A amplifier stages that they use. There are DAW plugins that specifically add harmonics to simulate what the outboard gear would be contributing.

 

[Doner Designs]

There are all kinds of things that are responsible for an amp's voicing, some intentional and some are lucky happenstance (like the venerable Fender tone stack).

Things like eq, filters, the non-linear way some circuits behave when loaded heavily, compression, frequency dependent compression, harmonics generation and their distribution, etc.

In amps with a distinct signature sound, would this typically result from an EQ circuit which simply puts the flat point somewhere other than the knobs at noon position?

 

[brianrost]

Plug into a Hi-Fi stereo system that's designed to be transparent. But u probably wouldn't like it, the guitar amp's magic is in the harmonics that the Hi-Fi community is trying to get rid of.

Some of us greatly prefer that mode, so I wouldn't be so quick to assume that. For upright bass or fretless I wouldn't have it any other way, personally. Vive la difference!

Once you sit in the control room of a great recording studio playing your bass DIed and pumped through some great monitors you won't be thinking about how sterile it sounds, believe me.

 

[beans-on-toast]

In amps with a distinct signature sound, would this typically result from an EQ circuit which simply puts the flat point somewhere other than the knobs at noon position?

Most EQ's have some setting that will produce an approximation of a flat response. But the important point is that a preamp adds more than EQ tone shaping. It also contributes harmonics.

If you have a PC, you can try this tone stack calculator: TSC. It allows you to get a general idea of the curves associated with different designs and what effect adjusting the tone pots has on the curves. These curves represent how the signal frequencies are boosted and attenuated in the tone stage.

A Fender tone circuit, which many companies have adopted, is doing something very different than a James tone circuit such as what Ampeg uses. It isn't just about the curves though. Different circuits affect overall performance just by being inserted into the preamp. It's more complicated than it appears, stages before and after interact with the EQ.

 

[Dsmnoisemaker]

Sound is not that complex..it is frequency, amplitude, and clipping..in musical terms, is EQ and dynamics.
Voicing is the art of selecting frequencies that will compliment the inherent dynamics or clipping behavior of the circuit.
If all amps were hifi..then we would only need EQ to match different amps. But non linearities introduced by preamp clipping, power amp distortion and speaker distortion is what makes each amp design a thing of its own..

What a kemper does is sweep all frequecies and amplitudes into an amp, and record the output, then reproduces the frequency response and dynamics of that output..pretty simple (although complex algorithms)

 

[40Hz]

But, can most amps, with proper EQ'ing be made to sound like any other amp?

If not, which is one amp whose voicing could not be duplicated?

There are basically two types of tonestack you'll run into with instrument amps. One is the FMV (Fender/Marshall/Vox) variety. The other is the less popular Baxandall tone stack used in certain Ampeg amps such as the B-15 series.

Because the FMV design has a mid frequency notch that's baked into it by its components, it lends itself to "signature sound" amps since the mids make up much of what we perceive as something's characteristic tone.

The Bax design is more flexible although less intuitive in operation for many musicians' tastes. A Bax actually can selectively control the midrange bump or cut. So there are tone settings you can get with a Bax tonestack that would be impossible to duplicate with an FMV circuit.

Theoretically a Bax should be able to duplicate anything an FMV equipped amp can get. But in actual practice it doesn't work out that way. Because things like different components (such as type and brand of tubes used - or opting for discrete semiconductors instead of integrated circuits), the design of the gain stages, the choice of speaker(s) and cabinet design, etc. all have a direct bearing on the tone or sound you get.

Amps are like coctails. They're a carefully selected (or sometimes just lucky) blend of ingredients that produce unique tasting drinks. The fact that hundreds of different cocktails use almost all the same ingredients doesn't mean they all taste mostly the same. The slightest change or minor substitution can have a major effect on the finished outcome.

Amps work a lot like that.

 

[40Hz]

What a kemper does is sweep all frequecies and amplitudes into an amp, and record the output, then reproduces the frequency response and dynamics of that output..pretty simple (although complex algorithms)

I've never gotten a chance to A/B a Kemper against the actual amp it's modeling.

Cone to think of it…I've never so much as seen a Kemper let alone gotten to hear one.

Are they that good?

 

[Ric5]

What creates a bass amp's "voicing"?

Everything ... the capacitors, the pots, the circuitry, the speaker type, the cabinet shape, etc ...

It is a full package

 

[Ric5]

Here's a question for everyone .
What is the most transparent head and cab one can buy?

Eden and GK are both known as amps that don't "color" the sound.

I like Ampeg and Hartke because I like the "color" they add.

 

[Clark Dark]

I have experienced great tone in a live setting by using my F-2b running the output of one channel into the input of the other. But then one day I had my brothers Mesa Boogie Mark 1 guitar combo amp with the cascading volume controls through a power amp and damn, there was the tone, the drive, everything I wanted to hear live but my brother won't part with it for anything. I see Mesa has deep switches built into their bass amps but I wonder if they even considered the cascading volumes? drool

 

[Doner Designs]

There are basically two types of tonestack you'll run into with instrument amps. One is the FMV (Fender/Marshall/Vox) variety. The other is the less popular Baxandall tone stack used in certain Ampeg amps such as the B-15 series.

Because the FMV design has a mid frequency notch that's baked into it by its components, it lends itself to "signature sound" amps since the mids make up much of what we perceive as something's characteristic tone.

The Bax design is more flexible although less intuitive in operation for many musicians' tastes. A Bax actually can selectively control the midrange bump or cut. So there are tone settings you can get with a Bax tonestack that would be impossible to duplicate with an FMV circuit.

Theoretically a Bax should be able to duplicate anything an FMV equipped amp can get. But in actual practice it doesn't work out that way. Because things like different components (such as type and brand of tubes used - or opting for discrete semiconductors instead of integrated circuits), the design of the gain stages, the choice of speaker(s) and cabinet design, etc. all have a direct bearing on the tone or sound you get.

Amps are like coctails. They're a carefully selected (or sometimes just lucky) blend of ingredients that produce unique tasting drinks. The fact that hundreds of different cocktails use almost all the same ingredients doesn't mean they all taste mostly the same. The slightest change or minor substitution can have a major effect on the finished outcome.

Amps work a lot like that.

What is typically used in modern solid state amps? I thought that both of the tone stacks you refer to had interactive controls whereas the EQ section of modern SS amps are (I think) more like a graphic equalizer that only has four bands.

 

[Dsmnoisemaker]

I've never gotten a chance to A/B a Kemper against the actual amp it's modeling.

Cone to think of it…I've never so much as seen a Kemper let alone gotten to hear one.

Are they that good?

I have never heard one, too but in paper, it should be pretty close to the real thing..
the downside is that it should interpolate the dynamics. It is not the same to clone the amp with low gain or high gain, as the dynamics are not linear, and i suppose that the kemper assumes certain dynamic behavior..

 

[catcauphonic]

Eden and GK are both known as amps that don't "color" the sound.

I like Ampeg and Hartke because I like the "color" they add.

I'm surprised because i see references to GK's 'baked in tone' quite often.

I'm learning a lot from this thread.

 

[KickingBass]

Eden and GK are both known as amps that don't "color" the sound.

I like Ampeg and Hartke because I like the "color" they add.

GK amps seem to have a good bit of baked in tone. My 700 RBII is pretty colored imo.

 

[agedhorse]

What is typically used in modern solid state amps? I thought that both of the tone stacks you refer to had interactive controls whereas the EQ section of modern SS amps are (I think) more like a graphic equalizer that only has four bands.

It can also be the combination or melding of different approaches, neither one or another alone. There can also be additional elements added to appeal to a specific type of player or playing style.

There have been some interesting oversimplifications suggested in this thread as to why different amps sound different. As someone who has designed amps for quite some time, I do find some of the suggestions amusing as they represent common urban or internet mytholog rather than actual, factual operating mechanisms.