Guide to comparing your modeler to your favorite tube amp

laxu

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"It doesn't sound the same as my tube amp" is a common complaint about modelers. Whether that is true or not depends on the modeler in question, but in most cases the setups for testing are nowhere even close to being equivalent.

Here's some closest "like for like" scenarios. As you can see all of them have some caveats, but overall will result in closer comparison than e.g modeler ->"FRFR" vs tube amp -> guitar cab.

Modeler setupTube amp setupIssues
Modeler -> IR cab simsTube amp -> loadbox -> IR cab simsLoadbox quality has an effect on tube amp behavior.
Modeler -> IR made of the miced real guitar cabTube amp -> real guitar cab -> micIt's a recorded sound so not what you hear in the room.
Modeler -> poweramp -> real guitar cabTube amp -> real guitar cabPoweramp quality has an effect on modeler sound.
Modeler -> poweramp -> real guitar cabTube amp -> loadbox -> poweramp -> real guitar cabLoadbox quality has an effect on tube amp behavior.
Modeler -> IR cab simsTube amp -> DI box -> guitar cab & DI -> IR cab simsReal cab should be in another room so you hear just the DI signal with cab sims.

Now that you have your setup, next things you need to consider:
  • Match volume levels. This is the most important part. Use a decibel meter if you have one, if not use an app on your phone as it's good enough for this. Even just a slight difference in volume will make us prefer the one that is louder.
  • (Fractal only) Find the closest matching speaker impedance curve if using a poweramp and real cab. This can be a bit of trial and error, but can have a significant effect in how close the modeler feels to the real tube amp. The modeler does not know what it's connected to so matching the behavior of the amp model to the real cab used can help.
  • Pick a reference tone. This is most likely your favorite tube amp at your favorite settings.
  • Do not try to use the exact same settings you use on your amp with the modeler! You can use them as a starting point, but there is variance in components so you will not get the same result by pointing the knobs in the same direction.
  • If you can, set up an A/B box to toggle between which device you are playing. If you don't own one, consider routing the signal through your modeler and from its outs direct to the amp.
  • Use your ears to match the sound, not your eyes. Sounds obvious, yes but a lot of people seem to miss this. Knobs at noon on everything is not the right way to go.
  • Use your best audio system, whether it's headphones or studio monitors. The quality of your output system matters.
Then you just start listening, dialing, toggling and listening. Hopefully eventually you will find yourself quite close to the real amp without having to adjust the modeler to some extreme setting. Touching advanced parameters should not be necessary either. Make sure you check that volume levels still match every now and then.

If you want you can record a DI track and pipe that through both devices to avoid having to play while you tweak but for the "feel" of the amp you need to play both.

This same guide works for trying to get the sound of an amp that does not exist in your modeler.
 
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Makes sense. Seems like a fools errand to me though. Not sure why so many are focused on making one thing sound exactly like something else. Get gear. Dial in a sound. Play guitar.
Exactly. I just fiddle with the settings til I like what I hear and don’t care if it sounds like something else. I wouldn’t expect my JCA100 to sound like my JCM900, so I take the same approach with the Helix models (and Fractals when I had an Axe FX).
 
I think those methodologies make sense as a way to increase the likelihood of getting similar results, but I agree with Khan.

Actually, I like it that my modeler sounds different than my amps and I like the way it sounds. When I want amp in the room tone I play through one of my amps.

Or I play through one of my amps with the modeler in the 4CM. Best of both worlds.
 
You need an option that compares amp into a passive DI capable of handling speaker level, with the THRU still connected to the real cabinet, which is the most transparent way to get the original amp signal in order to be able to do a comparison against it in the first place.
Thanks, added. Though in this scenario you would want to have the cab in another room so you can hear just the DI signal with cab sims to compare against the modeler.
 
Great post.

I think “load box quality” is a bit vague, it’s really how close the load box’s load characteristics are to the particular cab in question. 2 load boxes can be of equal quality and very accurate and still have different impedance curves, in the same way that 2 different cabs can.

I think the load and the poweramp settings in general are the most important ones to get right, in my experience the gain and EQ controls are usually a bit easier when the power amp side is right.
 
Great post.

I think “load box quality” is a bit vague, it’s really how close the load box’s load characteristics are to the particular cab in question. 2 load boxes can be of equal quality and very accurate and still have different impedance curves, in the same way that 2 different cabs can.

I think the load and the poweramp settings in general are the most important ones to get right, in my experience the gain and EQ controls are usually a bit easier when the power amp side is right.
That's fair but the explanation for reactive loadboxes vs resistive vs other reactive loads is a pretty long one.
 
The issue with comparing is that you start with 2 pieces of gear with different usecases that sound perfectly fine …and after you compare you end up with 1 piece sounding less then the other.
its a losing game..
 
The issue with comparing is that you start with 2 pieces of gear with different usecases that sound perfectly fine …and after you compare you end up with 1 piece sounding less then the other.
its a losing game..
You might find that "hey, I don't need one of these because this piece of gear can do all that." It has helped me pare down extra gear I had. I still do have a good amount of "does the same stuff but with a different approach" with my pedalboard and BluGuitar amp even if my Axe-Fx 3 could do most of that stuff.

I posted this on "the other place" as I feel people there need this more and here I'm kinda preaching to the choir.
 
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  • Match volume levels. This is the most important part. Use a decibel meter if you have one, if not use an app on your phone as it's good enough for this. Even just a slight difference in volume will make us prefer the one that is louder.
If you actually read into this, you'd find that phones are quite inaccurate, and so are the cheaper dB meters you can get on eBay and Amazon and the like. There can be variances up to 10dB in some cases, which is quite a lot. It's extremely easy for that slight difference in volume to not be detectable by your phone.

With phones, high sound pressure levels can distort the input, which will completely throw off the measurement. Plus the apps are thrown off by lots of low frequency content:

Plus, dB isn't the way to compare the final output volume of a playback system. You would want to measure sound pressure level. The REED Instruments R8050 is a decent one.
 
Thanks, added. Though in this scenario you would want to have the cab in another room so you can hear just the DI signal with cab sims to compare against the modeler.
Also this isn't accurate, because the idea would be you'd take a recording of the amp through the DI box, to get the rawest and most transparent version of that signal. From that point, you can turn the amp off and work entirely in the box.
 
I like that you laid it out so that everyone can make sure they're comparing apples to apples. I definitely prefer a quantitative approach though.
 
If you actually read into this, you'd find that phones are quite inaccurate, and so are the cheaper dB meters you can get on eBay and Amazon and the like. There can be variances up to 10dB in some cases, which is quite a lot. It's extremely easy for that slight difference in volume to not be detectable by your phone.

With phones, high sound pressure levels can distort the input, which will completely throw off the measurement. Plus the apps are thrown off by lots of low frequency content:

Plus, dB isn't the way to compare the final output volume of a playback system. You would want to measure sound pressure level. The REED Instruments R8050 is a decent one.
It really is crazy how much volume or "perceived" volume affects whether we think something sounds better or not.
 
It really is crazy how much volume or "perceived" volume affects whether we think something sounds better or not.
100%

but also...

Kinda.


Let's say you're after a JCM800 type tone. One of those really aggressive 'cut through the mix' brutal metal tones. And you get that from an amp modeller, but the amp modeller is quieter than the valve amp.

But let's say the valve amp is just a mere AC30, with the treble rolled fully off....


You're still gonna probably prefer the modeller in such a comparison, I would wager.


The irony seems to me that when the modeller and amp are quite similar, the minute differences become heightened, and you can really dial your ears into them. Whereas if the amp and modeller are really different, it's, usually quite easy to decide which tone you prefer.

IMO.
 
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