Custom IR comparison

G

gambapaketera

Inspired
Hi guys!!

Im working on capturing an IR of my V30 cabs, still not 100% done since i have to test some more mic placements and a few different mics/preamps, but so far it looks very nice!

As an example, i recorded a few riffs, captured the IR and recorded the same riffs again with that IR in a cab block.



Real cab is the first one...you can also see that the IR has a reverb on it (my bad, i didnt realize it was there).

I'm not at home so i can't really tell if the sound is as close as it seems here with cheap monitors, but it looks to me that im gonna love that function ;)

I will post the IRs once they are done.

Cheers :)
 
Now repeat the experiment with a real amp vs. the Axe-Fx model. You may need to adjust the speaker resonance stuff slightly to get an exact match.
 
Ok man you win gold ,First off I cannot tell the difference for the life of me .second quite frankly and maybe its the slight bit of "air" you added but the IR of the cab actually sounds better .


3rd What freaking amp sim is that in the first clip
 
Wow, cool stuff :) So basically I could make an IR from my cab. Use that IR for direct FOH stuff and have my "stage-monitor" with that cab which I IR'ed. Sounds like less tweaking - have to try that :) Is it better to use a neutral PA poweramp for creating the IR?
 
mDaniel said:
Wow, cool stuff :) So basically I could make an IR from my cab. Use that IR for direct FOH stuff and have my "stage-monitor" with that cab which I IR'ed. Sounds like less tweaking - have to try that :) Is it better to use a neutral PA poweramp for creating the IR?
Click to expand...

Yes. That way the FOH would sound like your stage cab.

For absolute accuracy a neutral PA should be used.... However, if you want to capture the interaction of a tube power amp and cab you can obtain the IR using the effects return of your tube amp. In this way you'll obtain a composite IR that is the combination of the power amp and the cab together. When you do this you should then turn the speaker resonances in the amp block down, possibly all the way to zero, or otherwise you are doubling the effect of the speaker impedance.

I've done this and it is really accurate but you lose some ability to shape the tone with the presence and depth knobs since the speaker resonance is no longer part of the power amp model. The controls will still work but they will have less affect.

IMO, the better way is to use a neutral power amp and then adjust the speaker resonances by ear to match (or taste). I actually have a speaker impedance tester so I can measure the speaker impedance and dial in the resonances but most people don't have one of those.

The default resonance values are selected based on the most commonly used cab for the amp model.

If enough people are interested I can write a short treatise on tube amp / speaker interaction and how speaker impedance influences frequency response.
 
FractalAudio said:
If enough people are interested I can write a short treatise on tube amp / speaker interaction and how speaker impedance influences frequency response.
Click to expand...
Please do. The more we know, the better we can create, and the more fun it'll be.
 
FractalAudio said:
For absolute accuracy a neutral PA should be used.... However, if you want to capture the interaction of a tube power amp and cab you can obtain the IR using the effects return of your tube amp. In this way you'll obtain a composite IR that is the combination of the power amp and the cab together. When you do this you should then turn the speaker resonances in the amp block down, possibly all the way to zero, or otherwise you are doubling the effect of the speaker impedance.
Click to expand...
Interesting - does this mean I should be turning down the speaker resonances for my live tube amp + traditional cab setup?

FractalAudio said:
If enough people are interested I can write a short treatise on tube amp / speaker interaction and how speaker impedance influences frequency response.
Click to expand...
Yes please! I'm really not getting the speaker resonance section of the amp block at all...
 
fredster said:
Interesting - does this mean I should be turning down the speaker resonances for my live tube amp + traditional cab setup?
Click to expand...

Maybe. There is no definitive answer as there are many variables. The power amp model in the Axe-Fx models the speaker impedance and it's interaction with the virtual power amp. When you use a tube power amp you are doubling the power amp "influence" so-to-speak.

If you are using a very colored tube power amp then turning off the power amp modeling may be advisable.

The best advice is to use your ears.
 
mDaniel said:
Wow, cool stuff :) So basically I could make an IR from my cab. Use that IR for direct FOH stuff and have my "stage-monitor" with that cab which I IR'ed. Sounds like less tweaking - have to try that :) Is it better to use a neutral PA poweramp for creating the IR?
Click to expand...
Its so amazing that it sounds like science fiction when you think about it! And it works wonders :)

Also, while doing this test i connected one of my guitars that is waaaay darker in sound than the strato used for this test. For that guitar i have to point the mic straigh to the cone of the cab to get more highs, but instead of that i did this just for fun and testing purposes.

With a parametric EQ after the cab block i did some surgical eq till i got a good balanced sound. Then with axe edit i exported the IR so i could open it with Axe-o-matic (great app :) ) and save it to wav. With the Wav file i could import it in cubase so in that track i could clone the EQ used in my axe-fx...after that i only had to export that wav again using the same settings and convert it again to axe-fx 2.

I dont know if that "system" is good or not, but i can tell you it sounded AMAZING.

BTW, i used an Art SLA 2 power amp for the recording. I had to alter the global eq in the axe-fx to "flatten" the response a bit (fellow user Javilinch posted his settings in the spanish forum...thanks a lot mate!!) and the amp sim is the Corncord, since i owned a MK50 for some time and i am more familiar with its voicing.

I cant stress enough how happy i am with my axe-fx...it seems to get better every day (not counting firmware updates :p )

Cheers!
 
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