Power amp with real cab garbage sound

clive9

Member
I know this has probably been discussed hundreds of times on this forum but I haven’t been around very long. Does anyone know how to get a decent sounds with a real power amp and cab. I’m running a matrix gt1000 through a 2x12 with v30s. I have always heard that cab sims should be off but without can sims it sounds like complete garbage. It’s very fizzy sounding ( I play rock/metal). However with cab sims on I have dialed in some great tones. I feel like maybe there is something wrong since everyone else says they get awesome tones with cab sims off. Any advice I’d appreciate!
 
my experience is the opposite, for the most part. Without cab sims on the amps sound huge, and with cabs on they sound small and overly filtered. If it's fizzy, check your gain, treble, and presence as you would with a "real" amp and you should be good to go.
 
I have cab modeling and power amp modeling on, too. Nothing wrong with it. Just trust what
sounds good to your ears and rock and roll with it, I say. :)
 
I've struggled getting my real cabs (2 Mesa 112s w v30/c90) with gt1000 to sound really good but they definitely do not sound good to me with cab sim on (which makes sense as that logically routes one mic'd cab into another real cab). One thing I have found is that I cannot just take a patch dialed in with frfr and route it to my real cabs and expect it to sound good even with a compensating eq stuck on the end. When I dial in a patch while monitoring through the real cabs I get pretty good sound but still hoping for better. I keep power amp modelling on and pick a good speaker impedance curve + set output mode to "SS pwr amp + cab". With my cabs, I seem to have to move the tone stack knobs + eq sliders a lot more vigorously to make a change, than with frfr.
 
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There's no hard and fast rule whether to have the cab or power amp sim on or off regardless of application, just a suggested use. If you're getting the tones you want with the cab on, that's all that matters. You're not doing anything "wrong".
 
There's no hard and fast rule whether to have the cab or power amp sim on or off regardless of application, just a suggested use. If you're getting the tones you want with the cab on, that's all that matters. You're not doing anything "wrong".
Nothing is wrong, and, "if it sounds good, it's good" (and all that), BUT running the output of a mic'd cab into a real poweramp/cab is not something one would logically anticipate to sound good, and for many would not in normal circumstance.
 
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Try selecting , the Resistive load Speaker impedance curve(in amp block) and let your power amp and cab manage it in real instead. if you are not using cab ir's, the wrong Speaker impedance curve can fuck things up, as it models the curve that the relationship between a real power amp and cab create when used together.

You can maybe try tweaking the speaker impedance curve from there , once you have the flat curve to your taste
 
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I know this has probably been discussed hundreds of times on this forum but I haven’t been around very long. Does anyone know how to get a decent sounds with a real power amp and cab. I’m running a matrix gt1000 through a 2x12 with v30s. I have always heard that cab sims should be off but without can sims it sounds like complete garbage. It’s very fizzy sounding ( I play rock/metal). However with cab sims on I have dialed in some great tones. I feel like maybe there is something wrong since everyone else says they get awesome tones with cab sims off. Any advice I’d appreciate!

Post your preset!

Also, what 2x12 cab are you running? If it's overly fizzy, a quick fix could be to add a Parametric EQ at the end of the chain, set the highest band to Blocking, then just start experimenting with those values until the fizz is sufficiently reduced.
 
for me, I turn the modeling and cab sim off when I use my two JCM800 half stacks that are loaded with EV-Black Labels, noting in front of these amps has ever sounded as good as my AX8 and FM3 (FM9 TBA, but sure it'll be same)
 
I'll have to keep experimenting with it but I have a pretty basic PA + cab setup (HoTone Loudster and 112 Fender Bassbreaker cab with V30) but with the power amp sim on and cab sim off it sounds just glorious to me no matter what amps I throw at it (patches created on studio speakers).
 
If turning cab sims on makes it better for you that means that there is an issue with the way you set things up. Cab sims will cut a lot of highs and will maybe bump up the lows.

Remember that stock presets or presets built for cab sims are not necessarily going to translate to a real cab. Without knowing how you set up the Axe-Fx amp block and how loud you are playing it's hard to give any more advice.
 
I would highly recommend you to recheck your setup according to this.
 

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Try selecting , the Resistive load Speaker impedance curve(in amp block) and let your power amp and cab manage it in real instead. if you are not using cab ir's, the wrong Speaker impedance curve can fuck things up, as it models the curve that the relationship between a real power amp and cab create when used together.

You can maybe try tweaking it from there , once you have the flat curve to your taste
plus if you can figure out the resonant frequency of your real cab (I used this method successfully after a lot of trial amd error), set lowrez freqency on the amp/speaker page to your determined resonant frequency and set loweez gain to taste with IC set to resistive load or other.

This helps your cab react to low end in an optimumally "tuned" manner. I my case its fairly subtle but made a differerce I think
 
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The amp block speaker impedance curve settings are hugely important.

When you power your speaker cabinet with a solid state amp, you lose the normal interaction between a tube amp and speaker. In the simplest and least accurate terms, the cabinet tends to sound dead and lifeless as a result. The same cabinet can sound radically different when powered by a tube amp versus a solid state amp. The tube amp tends to excite the high and low end more than the solid state amp, though its not exactly the same as an EQ.

That's where the speaker impedance curve comes in- it attempts to restore the effects of the interaction to the tone (which you might notice as more low and high end, though it also has more distortion in those areas.) If the simulated impedance curve doesn't match the curve of your real amp, it may not sound like you want it to sound. Thankfully, you can adjust it. I routinely find the high frequency resonance to be too much for my tastes and turn it down. The low end resonance can also be tuned to hit where the cabinet naturally wants to resonate.

I've only recently come to understand that the interaction (or lack thereof) between an amp and speaker cabinet is at least as responsible for the tone we hear as the frequency response of the speaker itself. The speaker impedance curve tab effectively gives you the tools of something like the Fryette PowerStation (and its adjustable reactive load) right inside the box. My experience with the Powerstation is that the reactive load settings make a HUGE HUGE HUGE difference in the tone.

If its too fizzy and harsh, try rolling back the high frequency resonance to about half what it is. Don't be afraid to put it where it sounds good to you. You can also try rolling off more high frequencies with the high cut but start with this.
 
The matrix gt1000 is marketed to be responsive in a manner close to tube amps even as a solid state power amp itself ,however as you find out it isn't necessary the case, so its better you get as familiar with Speaker Impedance curve settings. To help you dial the desired tone with the cab.

The other important thing is impedance , are you running the matrix poweramp at 1000 w at 8 ohms or 650 watt at 16ohms this can have a significant impact too.

In axe , power amp page there is a speaker impedance ratio, set to 1 by default, if the amp has no matching cab the amp(output impedance) will be around 8ohms (6.7ish actual DCR) , So if you run a 16ohms on poweramp to 8 ohms,it will sound harsh and fizzy probably ! so either try increasing the ratio to 2 or run it the power amp at 8 ohms and leave the setting as it is.

Find out the dc resistance of your cab and try to match it across the board.

Or turn power amp modelling completely off and just run matrix with impedance to match your physical cab impedance.

If output ohmage is higher than speaker ohmage it will have more fizz and hizz and definition desirable for some stuff but not neccessarily.
if speaker ohmage is higher than output ohmage it has like an opposite effect.

Be reminded latest gen fractals are the only devices that allow you this liberty, so while it may feel intimidating at first, it is actually a very handy tone shaping tool, whether you are using an ir or want a very well defined sound with a poweramp and cab.
 
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Post your preset!

Also, what 2x12 cab are you running? If it's overly fizzy, a quick fix could be to add a Parametric EQ at the end of the chain, set the highest band to Blocking, then just start experimenting with those values until the fizz is sufficiently reduced.
I am running through a Harley Benton 2x12 with v30s. I am using both the dizzy v4 and c++ for my amp blocks. I have got a killer tone with the cab sims on. I am just wanting to get a good sound without the cab sims off so I can see what truly sounds best. Since everyone else suggests cab sims be off I feel like I am doing something wrongs since is sounds so bad lol
 
Do you have the signal split so Output2 (or whatever output you are using to feed the Power Amp/Cab) is being taken off the main layout before hitting the Cab Block?
 
Perhaps not helpful but this has not been my experience at all. I use a solid-state power amp and cabs, and often the AFX is to me warmer and more compressed than my real amps. I have to actively remind myself to keep the gain and master volume on the low side on the AFX to avoid that. And I'm often surprised by how clanky and fizzy the real amps can be.
 
I am running through a Harley Benton 2x12 with v30s. I am using both the dizzy v4 and c++ for my amp blocks. I have got a killer tone with the cab sims on. I am just wanting to get a good sound without the cab sims off so I can see what truly sounds best. Since everyone else suggests cab sims be off I feel like I am doing something wrongs since is sounds so bad lol

That's what I'm getting at. If you're using a physical cab, then that's effectively an eq filter on your overall sound. Using a cab block on the grid plus a physical cab should sound super dark and muffled, like there's a blanket over your speakers, because that's effectively two eq's filtering out the highs and lows.

Here's something to consider. If you enable a cab block AND run your axe-fx into a physical cab, and then you start tweaking, you're going to be tweaking against that super dark, double-cab-filtered sound. That's why I'm asking you to post your preset. You could have just dialed in a hyper-bright, treble focused tone that doesn't sound good unless it gets double-filtered by the cab IR and physical cab. If you post your preset we can tell you how it sounds to us on our rigs.

My suggestion for now though would be to start a brand new patch from scratch without a cab block on the grid. Then start tweaking your sound from there, without a cab IR. If you still can't get a good sound after starting from scratch (including placing a PEQ at the end of the chain to chop off some extra highs if needed), then let us know. Actually, let us know either way.

So..
1. post your patch!
2. dial in a brand new patch without a cab block and see if you can make it sound good. After you're done, A/B it against your old patch and see which one you prefer.
 
I have the AF3 going into a Matrix GT1000FX which feeds a Mesa 2x12 Vertical cabinet. Almost every amp I throw at it sounds AMAZING, and with default settings as well. I don't even need to tweak amp settings to get a good tone. It sounds exactly like the real amp. I have cab and power amp modelling turned off in Global settings. And yes, post your patch and I'll run it through my system to see what it sounds like for me.
 
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