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Cab Block tone trick (to fix any tone issue you've ever had)

Discussion in 'Axe-Fx II User Cabs and IRs' started by shatteredsquare, Sep 25, 2017.

  1. shatteredsquare

    shatteredsquare
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    Psychoacoustic trickery!

    This will fix any tone issue you've ever had, with highs, or lows, or mids, or anything. The lows receive the most benefit though. I plugged the AxeFx into the aux input of my Yamaha THR-10 and the effect is audible and distinct even using speakers. To incorrectly quote Mixerman, "the most important aspect of any recording is the room it's made in."

    A Cabinet Impulse Response is a super short snapshot of the frequency response of a speaker in a wooden cabinet...the sine sweep used to map the response curve does get all of the frequencies, but if you play that sample only once, it's super short, it doesn't cycle and decay after the amp signal goes through it, even when the amp signal is a constant signal, it's just a static filter. The wavelength of some low frequency information can be longer in feet than the distance you are from your speakers, longer even than the length of the room you are in. If you playback an IR with low frequency information that has a longer wavelength than you are to the speakers, it will pass so quick it will be like it's not even there. BUT IT IS THERE. It's just not being given an opportunity to BREAAAAATHE.

    Room Level: 50% +/-
    Room Size: 1.17 +/-
    Mic Spacing: 22.2% +/-



    What this does is take what was a super short snapshot of the frequency response of the speaker, the impulse response (in the realm of a few milliseconds in duration), and lets the audio that just passed through that frequency filter spread out like it wants to, in a virtual space. You will notice that the lows immediately bloom and spread out, and mix with the mids and highs, you can hear the frequencies start to interact with each other like they normally would. If you take these settings and go back to the Factory IR slot 1 and go forward from there, it's hilarious how good they all sound, even the absurd ones. Any problems you were having with the low end, trying to tweak this or that because it it's sounding right, it's not resonating how you like...it's because the lows (and the mids and highs) are being choked out and restricted to a super short IR frame, and aren't allowed to disperse and interact with each other. This trick lets the lows out, which like in reality, allows them to hang around for just long enough for all of them to crash into each other and reproduce the sound you are USED to hearing from a speaker cab.

    Why is this necessary? Because it's a missing part of the signal process (recording process). Between a real guitar amp and a real microphone is a missing element of TIME. From the time you hit record, the TIME that is between the guitar amp and the microphone is affecting the sound on it's way to the microphone. If you send a guitar amp signal straight through an IR, while the frequency response will be exact, there is a missing element to the chain. This trick adds the TIME at the end of the microphone though, instead of in front of it.

    I'm not sure what it is, but something magical happens right at 50% room level, and right past that up to 51% or 52%. Changes of +/- 0.01 to the room size make drastic differences in how it responds. Mic spacing increases the stereo image, i think this setting only affects the perceived stereo field.

    Originally discussed here. I haven't done any recordings of it yet, but I fired up the AxeFx tonight to go back to some of the presets i put together with this, and my jaw hit the floor and i started laughing involuntarily again. That's the barometer I use for it something is really good or not. It's the same reaction i had when i fired up a Recto 2 Red Modern in Quantum FW for the first time.

    Video to follow, maybe another 6 months from now who knows. I bet it would be a lot easier to post a preset file to pass around, maybe I'll do that.
     
  2. FTR-greg

    FTR-greg
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    Interesting indeed. I tend to use the room parameters as it does sound more natural to me even when it is not really heard as a reverb affect. I'll have to dial a little more in and find the sweet spot, thanks for the setting recommendations. I learned this from time spent in actual studios and then by using Ocean Way rooms for DAW recordings in a "not" studio ;). What a difference it makes in a mix to have the room in there as well. thanks for reminding me!
     
  3. paulasbell

    paulasbell
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    I tend to use the Room parameter a lot in my presets, as well... but not nearly as small a room size, and not nearly as high a level. Gotta try that!
    Quick question, though. I can see that this would be big as a factor in a recording mix. But, does it work as well for live, where you're obviously IN a real room, as well?
     
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  4. muudrock

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    I've used the cab block Room effect since as long as I can remember. To me it's invaluable for doing what you described...Makes the sound and feel more realistic to me..
     
  5. shatteredsquare

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    The effect works live as well, out of speakers. If you think about the signal chain you're trying to emulate, its a guitar speaker pushing air in a space captured by a mic, so you'd expect the sound coming from your monitor of choice to sound like it would if you had miced up the cab. Between the speaker and the mic is some amount of air that in real life provides just a wee bit of diffusion and delay that will all mix together a bit and hit the mic at different times, in real life that spread and mixing keeps changing and swirling, it's never static. Sending an amp signal through an IR, even though the IR captured the correct frequency response, it's still a static filter as I understand, so there isn't any cross talk or mixing of the frequency spectrum. The time delay and diffusion is put at the back end of the IR though, where in real life it's between the speaker and the mic, but to my ears when you can dial in the phase and stereo separation you like, it provides exactly what I had been looking for with the resonance of a cab, how depending on how you play and mute the strings, the low end swells and blooms, but your ears can still track the fundamental like you get from a bass cab, even with headphones. I was having trouble finding that low end resonance out of straight up IRs until I put a little audio soft light on it. Now I can't find an IR that sounds bad.
     
  6. #6 shatteredsquare, Dec 2, 2018
    Last edited: Dec 3, 2018
    shatteredsquare

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    i have update, it's not a matter of giving the bass time to 'resonate' because it doesn't have enough room, it's adjusting the phase of the unicorn ears so that the point where the audio gets sourced out of la la land into your monitoring system is in the right spot in the wavelength to catch the full force of the low register, so your monitoring system has a full fundamental to push and you can hear it better. same thing ML does with his robot, but this is a VR way to adjust for any IR anybody shot, ever, even if the phase (mic placement) was poor to begin with. if you get an IR that's already great (@ML SOUND LAB ) and you do this it gets a little freaky how good it sounds.
     

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  7. Veloso1978

    Veloso1978
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    Hi everyone I know this threat are old... that’s influence the tone better ?
    Thanks a lot.
     
  8. shatteredsquare

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    it was better for me cause it was enabling any IR to sound great. It was just using early reflections from a low resource room sim to do comb filtering and smooth out the waveform of the IR. A cheap fix, but effective.
     
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  9. Black Bitch

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    I just discovered this thread and tried it last night at gig volume and is amazing how it smoothes the tone. I still have to invastigate more when playing with the band and also probably have to do some slight changes in EQ and Low/High frequencies in the Cab Block. Hier is a little sample. I will do another sample at the weekend, where I play one part without adding room in the Cab Block and than with it. So one can hear the difference for both.

    Edit: the first part is only amp, cab and reverb and from 0:16 i added Drive (TS808) and Delay.

     
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