Easy to clip Out2?

[Chris Hurley]

I continue to be impressed with all the "awesome" that Fractal managed to pack into the FM3 at such a reasonable price. As I use it, I find limitations and then I find workarounds. There are surprisingly few limitations.

I notice on the FM3 that when I set Out2 for unity gain (for 4CM applications), its pretty easy to get OUT2 to clip. With no boost/pad, it runs without clipping with just a guitar and in->out blocks. With the lowest level of boost/pad, I get clipping just from strumming the guitar hard. D/A hiss is reduced a little at the expense of a little clipping.

Does anyone else notice this behaviot? The Axe-FX 3 doesn't seem to do that. I wonder if the FM3 has "significantly" less output headroom before clipping than the Axe-FX3?

(Boost/pad is useful in 4cm to knock down what is otherwise inevitable d/a conversion hiss that cannot be suppressed with any gate and has nothing to do with any blocks. Its just a result of D/A conversion and this is why boost/pad exists)

The good news is that if you're trying to push an amp, this initial level of clipping doesn't seem to be meaningful other than the red light flashing regularly.

 

[marshall2553]

I haven't ran mine in 4CM in a while, but I did run into that when trying to hit the front of my amp with a boost in the FM3. Something like a tube screamer with the level cranked and the gain low would light up the OUT2 clip indicator.

 

[Chris Hurley]

I haven't ran mine in 4CM in a while, but I did run into that when trying to hit the front of my amp with a boost in the FM3. Something like a tube screamer with the level cranked and the gain low would light up the OUT2 clip indicator.

You basically can't get much out of it as a boost... Unless I'm missing something, which is entirely possible.

 

[Rex]

You basically can't get much out of it as a boost... Unless I'm missing something, which is entirely possible.

The Boost/Pad function doesn't change your output level at all. It's there to make sure you're hitting the internal D/A converters as hard as possible without clipping. That's its only job. It won't boost or cut your output signal.

 

[Chris Hurley]

The Boost/Pad function doesn't change your output level at all. It's there to make sure you're hitting the internal D/A converters as hard as possible without clipping. That's its only job. It won't boost or cut your output signal.

I think you're thinking of the input pad feature. I'm talking about the boost/pad on the outputs.

It doesn't change the level but it absolutely changes the point at which the output will clip which effectively limits the output level you can get...

This means you trade your ability to have a hot output signal for a reduction in hiss.

 

[Rex]

I think you're thinking of the input pad feature. I'm talking about the boost/pad on the outputs.

Nope. We’re both talking about the same thing.

It doesn't change the level but it absolutely changes the point at which the output will clip which effectively limits the output level you can get...

This means that you trade your ability to have a hot output signal for a reduction in hiss.

That’s what Boost/Pad is all about. It doesn’t change the level; it only changes what level you start to clip at (and how much noise is on your signal).

 

[laxu]

The boost/pad labeling is really rather confusing. Is it boost or pad if it says 6 dB without any plus or minus?

 

[Rex]

The boost/pad labeling is really rather confusing. Is it boost or pad if it says 6 dB without any plus or minus?

The boost/pad labeling is really rather confusing. Is it boost or pad if it says 6 dB without any plus or minus?

"6 dB" means the input to the D/A converter is boosted by 6 dB, and the output of the converter is padded by 6 dB.

 

[laxu]

"6 dB" means the input to the D/A converter is boosted by 6 dB, and the output of the converter is padded by 6 dB.

Which is rather unintuitive to the end user without knowing those details. There must be a better way to present it.

 

[Rex]

Which is rather unintuitive to the end user without knowing those details. There must be a better way to present it.

What do you suggest?

 

[Chris Hurley]

Nope. We’re both talking about the same thing.



That’s what Boost/Pad is all about. It doesn’t change the level; it only changes what level you start to clip at (and how much noise is on your signal).

My point is that it limits your output headroom before clipping.

 

[Chris Hurley]

Nope. We’re both talking about the same thing.

No we're not. Boost pad is not there to make sure you're hitting the internal d/a hard enough. That is input pad. Boost/pad and input pad are two completely different things with two completely different purposes.

 

[GlennO]

No we're not. Boost pad is not there to make sure you're hitting the internal d/a hard enough. That is input pad. Boost/pad and input pad are two completely different things with two completely different purposes.

From the manual:

The optional Boost/Pad function on Output 2 can be used to lower the noise floor. To find the right setting, adjust this to be as high as possible without clipping, as indicated by a red LED on the front panel meters. The volume won’t change but you should hear the FM3’s noise floor drop as you increase boost/pad.

TBH, I don't follow what you're trying to say about headroom. A device like an FM3 doesn't have "headroom". Clipping will occur at digital zero and is solely a function of the level you send into the D/A converter. That doesn't vary from device to device.

 

[Chris Hurley]

The output circuits certainly do have an output headroom. The evidence is how I can clip the output on my Fm3 with just a guitar in to out on the first boost/pad setting while on an axe3 it does not clip on the first or even second setting.

There is a difference in headroom.

Also, they're is nothing in that bit of the manual referring to hitting the a/d or d/a hard enough. That is input pad and refers to the a/d conversion.

 

[Chris Hurley]

Reread the original post people. It's quite clear. I'm asking why it is so easy to clip the Fm3 output compared to the axe3 when boost/pad is employed. This isn't complicated.

 

[GlennO]

You're saying you think there is a boost even though you have it set to 0dB? That's easy enough for you to verify by looking at the meters in the grid.

 

[Chris Hurley]

I'm saying it clips easy when you set it above 0 where the axe3 does not. You basically can't use it for a boost into an Amp and use boost/pad for lower noseat the same time on Fm3 without clipping where you can on axe3.

 

[GlennO]

Right, but you’re saying the boost/pad works differently on the two devices. I’m saying you can use the meters to test your theory by verifying the grid output in your situation is the same on both of them. Otherwise, the issue may be upstream.

FWIW, I can see now you’re using “boost” to mean two different things and that’s what caused the confusion above.

 

[Rex]

My point is that it limits your output headroom before clipping.

You're right. It does. That's why you can't just dime it without thinking about it. If it weren't for that limitation, you'd run it wide open all the time so you could get the maximum noise reduction, and there wouldn't even be a control for it.

Boost pad is not there to make sure you're hitting the internal d/a hard enough. That is input pad. Boost/pad and input pad are two completely different things with two completely different purposes.

Yes, Boost/Pad is an output thing. Its job is to lower the noise floor by hitting the D/A converter as hard as possible without driving it into clipping. That maximizes the dynamic range of the converter, which results in a less-noisy signal.

D/A means digital-to-analog. The D/A converter is where the internal digital signal gets converted into an analog signal to be sent to the outside world. That happens at the output. From the Axe-Fx III owner's manual:

You basically can't use it for a boost into an Amp and use boost/pad for lower noseat the same time on Fm3 without clipping where you can on axe3.

That's correct. You can't use it for a boost into an amp. It doesn't work that way. Neither does Boost/Pad in the Axe III.

Reread the original post people. It's quite clear. I'm asking why it is so easy to clip the Fm3 output compared to the axe3 when boost/pad is employed. This isn't complicated.

If the Boost/Pad function clips your FM3's outputs earlier than your Axe-Fx III's outputs, it's because you're running your internal levels hotter in your FM3. Set your levels to 0 VU in both devices, and you'll see that they both behave the same.

 

[laxu]

What do you suggest?

I honestly don't have a good idea right now. Maybe the label needs to be something made up like "noise optimizer" with values that are something like simple 1/2/3/4 so people will actually find the setting by ear that to them has least noise without clipping.

If I see boost/pad on an input or output I expect it either boosts the level or it pads the level. In the past before it was changed to -10 dB/+4 dB there was another boost/pad setting which made this even more confusing.