Boosting Mids: I do not think that means what he thinks it means

Deadpool_25

Deadpool_25

Fractal Fanatic
A post on another forum got me looking a little into how amp tone stacks work. From what this article says (seems legit, but I don't know for sure), amp tone controls in a Bassman-style circuit (which apparently is quite common) don't necessarily work all that intuitively.

- Treble actually reduces bass and mids*
- Bass actually reduces mids and treble*
- Mid is actually a volume boost, boosting all frequencies

*Perhaps with a corresponding overall gain boost to make up for the loss of volume from lowering a section of the frequency curve.

Here's a quote from the linked article about this type of circuit:

"From a perfectionist/engineering standpoint, there is a lot wrong with this circuit. The controls are complexly interactive. There is no really flat setting, as there is a residual midrange scoop unless the Treble and Bass controls are fully down. The action of the Bass control is very uneven for normal taper controls. While the Mid control appears to affect only the mids, it is actually a form of volume control that affects all frequencies, but is the only control that also affects mids. Although it has several imperfections, this tone stack actually helps some of the quirks of guitar, so it works well."

Does boosting the mids actually work more as a volume boost than a tone-shaping tool?
Do amp manufacturers usually compensate for these things with hardwired EQ (high/low pass filtering?) before it even hits the tone stack?

Maybe this is all old news to you guys, but I did find it interesting.
 
It looks like bass and treble function like a baxendall tone circuit, which is quite common in a lot of amps and dirt pedals. Catalinbread in particular seems to love this kind of tone control.
 
Muad'zin said:
It looks like bass and treble function like a baxendall tone circuit, which is quite common in a lot of amps and dirt pedals. Catalinbread in particular seems to love this kind of tone control.
Click to expand...

Hm. In what product? I’d think @FractalAudio modeled tone stacks appropriately for specific amps. If so, I’d guess both types and more are represented in the AFX/AX8.
 
Deadpool_25 said:
A post on another forum got me looking a little into how amp tone stacks work. From what this article says (seems legit, but I don't know for sure), amp tone controls in a Bassman-style circuit (which apparently is quite common) don't necessarily work all that intuitively.

- Treble actually reduces bass and mids*
- Bass actually reduces mids and treble*
- Mid is actually a volume boost, boosting all frequencies

*Perhaps with a corresponding overall gain boost to make up for the loss of volume from lowering a section of the frequency curve.

Here's a quote from the linked article about this type of circuit:

"From a perfectionist/engineering standpoint, there is a lot wrong with this circuit. The controls are complexly interactive. There is no really flat setting, as there is a residual midrange scoop unless the Treble and Bass controls are fully down. The action of the Bass control is very uneven for normal taper controls. While the Mid control appears to affect only the mids, it is actually a form of volume control that affects all frequencies, but is the only control that also affects mids. Although it has several imperfections, this tone stack actually helps some of the quirks of guitar, so it works well."

Does boosting the mids actually work more as a volume boost than a tone-shaping tool?
Do amp manufacturers usually compensate for these things with hardwired EQ (high/low pass filtering?) before it even hits the tone stack?

Maybe this is all old news to you guys, but I did find it interesting.
Click to expand...

If you want to see how various tone stacks behave download this: http://www.duncanamps.com/tsc/

Baxandall tone controls are rare in guitar amps.
 
That tone stack calculator is a timeless classic. Note: the passive Baxandall circuit in that program is called "James."
 
That's one thing that I love about the Carvin amps - the Baxandall stack makes the cleans pop. You can get an incredible amount of high end shimmer out of them!
 
That quote is misleading in places.

If you set bass, mid and treble at 5, then yes, overall there is middle cut. But don't forget that this compensates for the general mid-boost of typical guitar pickups. That's why they work so well together to give a good balance of low, mids & highs.

To generalise:
Treble increases high while also lowering the mid and bass levels.
Mids lessen the amount of mid-cut.
Bass is the most independent of the controls, it pretty much only controls low end.

On common tone-stacks there IS a fairly flat setting with bass and treble set to minimum (adjust mid for volume).
 
Last edited:
Yea, thanks. Not worth it bothering with it for this instance. I'd probably go the virtual machine route if I really needed to run something.
 
IIRC, Mesa tends to use the same type of tone stack, which is why their manuals mention how interactive their tone controls are. It does add complexity, but as was mentioned, it normally works out for guitar frequencies.
 
You must log in or register to reply here.
Back
Top Bottom