High cuts required when running a modeler into guitar speakers?

[Jarick]

@Jarick Won't the Captor itself change the response of the power amp though? It's got it's own impedance curve which will be slightly different to running the cab. So you won't be seeing exactly the same high end behaviour as when there's a speaker attached ?

Not sure, but will find out. If anything I can see the delta between the two amps.

I could also see if I can measure the frequency response impact of the impedance curve and set that as a target so I can view the differences.

 

[DieSchmalle]

Decided to answer the question myself, and ordered a used Torpedo Captor. That's going to let me measure the Katana power section, as well as use with the incoming Blackstar HT-5 for attenuation or getting a direct signal.

So by next weekend I should be able to answer a lot of questions:

• Is the Katana a flat power amp or colored?
• What's the sonic difference between the Katana power amp, effects loop return, or front panel?
• What's the difference between the Katana power amp (solid state) and Blackstar power amp (tube)?
• Are high cuts required for modelers when running into a speaker cabinet?
• What are the sonic differences between modelers (Fractal, Line 6, Kemper)?

If you're careful with the level you just need an audio interface. Set the output control to 0.5W and record parallel to the speaker with a pair of clamp cables. Just make sure there is no risk of shorting the speaker out.

 

[EOengineer]

I’m under the influence of a ton of DayQuil right now so I might have missed details, but it seems to me like anyone running a full amp model into any real amplifier is going to be stacking impedance curves, which in most cases will result in overhyped highs and lows.

I must be missing something.

@Jarick Won't the Captor itself change the response of the power amp though? It's got it's own impedance curve which will be slightly different to running the cab. So you won't be seeing exactly the same high end behaviour as when there's a speaker attached ?

If you use the captor in-line with a cab attached, you get the impedance interaction of the real power amp and attached cab. If you use the captor with no cab, then you get the interaction of its internal reactive load.

 

[Jarick]

I’m under the influence of a ton of DayQuil right now so I might have missed details, but it seems to me like anyone running a full amp model into any real amplifier is going to be stacking impedance curves, which in most cases will result in overhyped highs and lows.

I must be missing something.



If you use the captor in-line with a cab attached, you get the impedance interaction of the real power amp and attached cab. If you use the captor with no cab, then you get the interaction of its internal reactive load.

Good thoughts, but it doesn't seem to make enough of a difference.

I dialed in a great sounding tone with my studio monitors earlier today using an IR with high/low cuts. Then I disabled the cab and ran into the power amp in of the Katana, it sounded super harsh. Tried different impedance curves and very subtle differences but not make or break. If I disabled cabs globally there's a tiny bit more EQ difference but again not enough to really change things.

Seems like it's nearly a 50/50 split from what I can tell, of people who run some kind of high cuts with real cabs or not. If I don't run them, I have to basically turn presence all the way off and reduce the treble in the tone stack a fair amount.

 

[luckymethod]

I've been running all my amp modelers through the Power Amp In of the Boss Katana Artist Mk2 and finding that all of them require a lot more high cuts than I expected. Especially with higher gain tones, they all need cuts around 6-8k like I was going direct to "FRFR"'s, but I'm going to a high watt Greenback style speaker. It's surprising because the amp is kind of dark sounding when running into the front of it, and there's very little harshness to speak of normally.

I'm curious if anyone else is finding the same thing?

For the record, I've tried this with HX Stomp, Axe FX 3, and today running Tonex and NDSP plugins. If I include the cab modeling, it's dark and bassy (kind of as expected), but if I turn off the cab modeling I need to chop off the highs around 6-8k.

Hi cuts are mostly required for two reasons:

- Make space in the EQ for other stuff when recording real cabs, some mics can be harsh
- remove high frequency content due to aliasing

the second is becoming less and less a necessity cause all the major modelers are improving the aliasing situation, getting to the point that in most cases at least in Fractal land I don't feel like they are very necessary.

 

[Elric]

I’m under the influence of a ton of DayQuil right now so I might have missed details, but it seems to me like anyone running a full amp model into any real amplifier is going to be stacking impedance curves, which in most cases will result in overhyped highs and lows.

I must be missing something.



If you use the captor in-line with a cab attached, you get the impedance interaction of the real power amp and attached cab. If you use the captor with no cab, then you get the interaction of its internal reactive load.

The Katana's power amp should not have any impedance related dependency because it is a solid state power amp.

The variable frequency response dependency on the speaker loading in a tube power amp is specific to the way the output transformer and the speaker interact (and varies with the specific cab/speakers connected), a solid state power amp will not exhibit this behavior because they work in an entirely different way. So the modeler's impedance modeling is likely a good thing when using SS power unless the power amp has some kind of compensation trying to simulate this effect (i.e. analog stuff like current feedback or some kind of digital DSP 'sauce' added).

If you are using tube power with a digital modeler, you will double down on speaker impedance behavior (simulated+IRL) unless you either disable power amp modeling or tweak impedance behavior via deep params. IME, you can use ears on this front, though...

I tend to not disable power amp sims with tube power, I just dial the preset for the amp+cab it is driving and my target SPL and tend to leave it be. If I do mess with them I tend to just lower the peaks on the impedance params on the Axe. I find the models start to sound too flat/uninspiring with the power amp modeling off or completely flat impedance curves. It is definitely worth experimenting with the options... the Axe III into a tube power amp+cab can be shockingly good, even for a digital 'old hand', for example. IMHO.

 

[DieSchmalle]

The Katana's power amp should not have any impedance related dependency because it is a solid state power amp.

The variable frequency response dependency on the speaker loading in a tube power amp is specific to the way the output transformer and the speaker interact (and varies with the specific cab/speakers connected), a solid state power amp will not exhibit this behavior because they work in an entirely different way. So the modeler's impedance modeling is likely a good thing when using SS power unless the power amp has some kind of compensation trying to simulate this effect (i.e. analog stuff like current feedback or some kind of digital DSP 'sauce' added).

If you are using tube power with a digital modeler, you will double down on speaker impedance behavior (simulated+IRL) unless you either disable power amp modeling or tweak impedance behavior via deep params. IME, you can use ears on this front, though...

I tend to not disable power amp sims with tube power, I just dial the preset for the amp+cab it is driving and my target SPL and tend to leave it be. If I do mess with them I tend to just lower the peaks on the impedance params on the Axe. I find the models start to sound too flat/uninspiring with the power amp modeling off or completely flat impedance curves. It is definitely worth experimenting with the options... the Axe III into a tube power amp+cab can be shockingly good, even for a digital 'old hand', for example. IMHO.

Yes. I expect the Katana's power amp to be flat for those reasons. Measuring it's output with an attached speaker would prove it. White noise in -> flat line out. If this doesn't gets us a flat line the next step would be measuring it with a load resistance (flat impedance) to see whether it reacts to speakers.

 

[Elric]

Yes. I expect the Katana's power amp to be flat for those reasons. Measuring it's output with an attached speaker would prove it. White noise in -> flat line out. If this doesn't gets us a flat line the next step would be measuring it with a load resistance (flat impedance) to see whether it reacts to speakers.

Depends on how you are doing measurements. If you measure your output signal with a mic you are likely measuring the frequency response of the Kat's speaker and the mic rather than the Kat's amplifier. You'd need to measure the actual amp's output, but, yeah, of course you can measure the amplifiers behavior as long as there is no post processing going on after the FX Return/Power Amp In.

I doubt if it is worth the effort to characterize it, though, TBH. If it needs a high cut to sound good, apply a high cut. Or get a different amp. Measuring would just quantify whatever the OP does not like about it but is not going to solve anything.

 

[la szum]

Hi cuts are mostly required for two reasons:

- Make space in the EQ for other stuff when recording real cabs, some mics can be harsh
- remove high frequency content due to aliasing

the second is becoming less and less a necessity cause all the major modelers are improving the aliasing situation, getting to the point that in most cases at least in Fractal land I don't feel like they are very necessary.

Excellent points! And then there is all the slicing and dicing going on at a FOH mixing desk, or in a DAW
when marrying tracks to fit into an extended mix.

Nothing is ever meant to exist in some kind of isolated pure state when it comes to instruments. It seems
to all be context related and dependent. To me.

 

[Alex Kenivel]

I doubt if it is worth the effort to characterize it, though, TBH. If it needs a high cut to sound good, apply a high cut. Or get a different amp. Measuring would just quantify whatever the OP does not like about it but is not going to solve anything.

Curious cats gonna split them hairs!

 

[JiveTurkey]

Curious cats gonna split them hairs!

I shot an IR of the Mustang GT speaker once. Once.

 

[DieSchmalle]

Depends on how you are doing measurements. If you measure your output signal with a mic you are likely measuring the frequency response of the Kat's speaker and the mic rather than the Kat's amplifier. You'd need to measure the actual amp's output, but, yeah, of course you can measure the amplifiers behavior as long as there is no post processing going on after the FX Return/Power Amp In.

I doubt if it is worth the effort to characterize it, though, TBH. If it needs a high cut to sound good, apply a high cut. Or get a different amp. Measuring would just quantify whatever the OP does not like about it but is not going to solve anything.

Just tapping the power amp signal and comparing it with the power amp in signal. If the signal fed to the power amp is white noise you can directly see the frequency response of the power amp with a frequency analyzer.

 

[Alex Kenivel]

I shot an IR of the Mustang GT speaker once. Once.

I cant even remember if I even gave the OG Kat speaker a mic before I swapped it out

 

[DieSchmalle]

I cant even remember if I even gave the OG Kat speaker a mic before I swapped it out

...and replaced it with...?

 

[Alex Kenivel]

...and replaced it with...?

A G12M-65 Creamback

 

[Jarick]

I picked up the Blackstar HT-5 head (Mk2 version) yesterday and have spent a couple hours now with it. The Katana Artist speaker is connected via a standard speaker jack, so I'm able to run the Blackstar head directly to that and use it like a traditional speaker cabinet. For reference, it's a pretty big 1x12 cabinet, roughly half open back, and the speaker is the Waza model which is like a high powered Greenback.

There's definitely a noticeable sonic difference between running into the Katana power amp in and the Blackstar effects return. With the Katana, I've had to run a high pass filter around 6k to tame the shrill high end. With the Blackstar, that shrillness is basically gone and it sounds much better. I do find I still have to turn the treble and presence down just a bit, but I don't need to run the high pass.

There may also be some compression happening with the Blackstar, although that could just be the presets I've played around with. It can definitely be loud and clean, but it seems to smooth things out a little more than just using a solid state amp. And that could also just be the difference between tubes and transistors.

I should be getting the Two Notes Captor 8 today, and then I can do some measurements of the power amps and see if what I'm hearing bears out on the graphs. And even if there's a simulated impedance curve, I should still be able to see the differences for the amps regardless.

What's kind of funny is that the Blackstar head was actually quite a bit cheaper than just about any half decent power amp. Granted it's a low watt tube amp and not 100+ watts, but for home use that doesn't make a difference. If I run straight into the amp, 0.5 watt mode is a lot better (cuts the volume in half basically) and I still don't have the master volume above 9:00.

And then the Kemper should be arriving over the weekend, so that will be another layer of fun to play around with.

 

[Jarick]

I will also say that, running the guitar through the Axe FX 3 into the effects loop return of the Blackstar HT-5 and the Waza speaker are the closest thing to a good amp with pedals/effects that I've experienced, especially at low volumes for home. Right off the bat it's a lot more fun to play through the Axe 3 with way, way less fuss (no IR's to worry about). It may very well be the best sound I've gotten from this unit.

 

[Jarick]

Torpedo Captor has arrived!

So I've never seen one of these in person and thought they were like the size of a guitar pedal. This thing is bigger and taller than my HX Stomp and pretty heavy!

 

[Elric]

Torpedo Captor has arrived!

So I've never seen one of these in person and thought they were like the size of a guitar pedal. This thing is bigger and taller than my HX Stomp and pretty heavy!

Yes, a load box is necessarily going to have a decent footprint due to the amount of power it would need to soak.

 

[Jarick]

Me on May 15th:
"I would never buy a tube amp because I'd need to have an attenuator/reactive load to play at home and the whole thing is a waste of money when I already have an Axe FX 3."



Me, two weeks later:
"I'm running my tube amp through my reactive load into the Axe FX 3."



Granted, the HT-5 and Torpedo Captor 8 were a combined $400.