Why do you need to roll off the cab block for live presets?

Discussion in 'Discussion' started by Dave_5150, Jun 9, 2019.

  1. Dave_5150

    Dave_5150 Senior Member

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    Not a complaint in anyway but why do you need to roll off the cab block for live work. I've looked at the curves of IR's from a range of vendors in the free version of CabLab and they're all more or less less done by 10Khz. However the advice is always to roll off the cab block well before that here (usually 6Khz to 8.5Khz)?
     
  2. slateboy

    slateboy Senior Member

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    I think thats only necessary for the fizzy/harsh (dare i say “poorer”) sounding cab IRs
    In a mix (live) situation the sound engineer often rolls off anything below 100Hz and often above 7 or 8kHz. This leaves space for the other instruments. A good example is to listen to an isolated guitar track for reference. The guitar+amp by its very nature is a mid-sounding instrument. What we, as guitarists, enjoy is a broader frequency coverage when playing in isolation or practice situations, quite a bit of which can be discarded when placed amongst the other instruments.
    I guess the bottom line is what we enjoy at home (where we can hear the complete amp-sound) may not be what is suitable for the live situation. You could just leave it as “you” like it and let the FOH/desk/engineer filter out what isnt required.
    I think its important that the player is happy with their sound to give them the confidence needed to perform at their best.

    Forgive me if im telling you stuff you probably already know.;)
     
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  3. jet66

    jet66 Active Member

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    I was wondering about how this works in general, being fairly new to using IRs. I've only been using a Headrush FRFR, so I don't know about going into a DAW or FOH, but I was definitely finding that most IRs (from a variety of well-respected sources) do best when I am not going above 6.5k-7k on the rolloff, with the Q between .5 and .8. One source's documentation even specifies rolling off at 7kHz on the upper end and 100Hz at the bottom. (I add a PEQ 0.1kHz highpass to the individual patches when needed.) Going above the 7kHz usually does seem to be a bit 'pointy' to the ears through the FRFR, especially with higher gain patches.
     
  4. Jace Nuzback

    Jace Nuzback Senior Member

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  5. Jay Mitchell

    Jay Mitchell Member

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    You don't.
     
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  6. viden

    viden Well-Known Member

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    Could you, as an expert, elaborate? - cause I've experienced the same thing with all IRs I've used so far.
     
  7. Jay Mitchell

    Jay Mitchell Member

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    If the IR actually captures the sound of the speaker, your monitor is reasonably neutral, and if you don't need to roll off the sound of the physical speaker, you will not need to roll off the IR. I never need to roll off my IRs.
     
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  8. Jace Nuzback

    Jace Nuzback Senior Member

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    CAB BLOCK-Obviously the IR you load will make a HUGE impact on the tone. But the ROLLOFF parameter is very important. The best results come with settings between 6kHz and 10kHz. This is the best way to dial out the high frequency fizz that some people complain about. The PEAKING parameter is also very important. For darker sounds set to.70. For brighter sounds set it to 1.00. For any amp model that sounds too bright to you, set this all the way down to .50.
     
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  9. Dave_5150

    Dave_5150 Senior Member

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    My main reason for asking was that I'd found that at home but with volume that I'd been happy with my new set of ML Sound Lab IR's with no cuts but all through my FRFR but the advice on here had suggested that wasn't right for live use. And I was wondering how to set my newer presets up.

    I tried tonight at rehearsal volumes though their house PA and I found that I preferred the roll off with those IR's higher on that system backed off a little but still much higher than what appears to be typical. However my presets were still usable at 20Khz with the presence a little lower too.
     
    Last edited: Jun 12, 2019
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  10. Matt

    Matt Well-Known Member

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    There is a long thread on this over on TGP. The issue is with the way nearly all IR’s are captured. Using standard mic techniques the IR not only captures the sound coming from the speaker, but also reflections.

    Since room reflections add to the bass response, if you have the reflections in the IR and then play through an FRFR that is also in a room with bass boosting reflections, you will get a double dose of extra bass requiring a rolloff to make it sound more like the original cab at higher volumes. (Fletcher Munson helps at lower levels)

    The highs often need to be rolled off because guitar cabs are directional and we usually listen to them with our ears off axis. A close mic captures more upper end than what we typically hear in a live situation.

    The solution to both problems is an IR captured off axis and without reflections using a 2 meter ground plane measurement technique. Jay Mitchell, the speaker designer behind the Atomic CLR has made some IR’s this way and has shared a few. They are eye opening for sure. Hopefully someone in the commercial IR field will catch on soon.
     
  11. Matt

    Matt Well-Known Member

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  12. Clint Martin

    Clint Martin Senior Member

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    No harm in using the tools available to get the sound you want.
    I've been using LIve Ready Sound IRs for awhile now, and they are eq'd and processed to sound good.
    I have my roll off somewhere between 6 and 7 and just leave it there for everything.
     
  13. Dave_5150

    Dave_5150 Senior Member

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    Yep, I've also been following that post with interest. Too technical for me but the shared IR's sound very good in some of the user clips.
     
    Last edited: Jun 16, 2019
  14. Dave_5150

    Dave_5150 Senior Member

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    I've had time to set up a few more presets today with the roll off around 7Khz with a few of the top IR providers using single mic and their mixes. To be fair this sounds a lot more like the guitar sounds I hear when I attend gigs at local clubs.
     
  15. jet66

    jet66 Active Member

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    That thread goes way over my head on the technical info, but the discussion around it is giving me a better understanding of the typical IR. It's really helped in understanding why I seem to have to tweak them.
     
  16. slateboy

    slateboy Senior Member

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    Could you share a recording of what you consider the “unpleasant” IR sounds so we get an idea of the issue, please?
     
  17. jet66

    jet66 Active Member

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    Not likely, as I'm not very experienced with accurately capturing a particular sound via microphone. It's not that they are typically 'unpleasant' in and of themselves, but as many others experience with an FRFR at band volumes, there often seems to be a need to rolloff the frequency around 6-7kHz. (Especially with high gain tones, in particular.) Otherwise, there can be some very harsh higher-end sounds that sound unnatural, that's the best word I can think of. And it goes beyond tweaking the presence or using the GEQ, for example. What I think sounds great through headphones and Garageband has not been as great when it's bouncing around a room at live band levels, that's the best way I can describe it. Usually cutting it down to 6.5k-7k and the Peak Q to less than 1.0 removes those particular sounds. I can also take the same preset, turn off the CAB modeling for the output, and put it into a Duncan Powerstage + 2x12 cab (Veteran 30/G12H30 mix) and not experience the issue at the same volume. Of course, that's not going to sound like a Brand X 4x12 with YYY speakers as intended by a particular IR, so a comparison like that only goes so far, I suppose.

    Prior to getting the AA6, I had zero experience with using IRs, so building my own tones from scratch, where the blank preset cabs have the rolloff all the way up at 20kHz, was a little frustrating at first. Looking at a lot of the factory presets for higher gain, I could see where they were typically rolled off, and copying that idea worked. As far as unpleasant IRs regardless of rolling off the higher end goes, I think that is just an effect of the particular mic set up of an IR paired with a particular amp model vs. the reflections of the room I am playing in. I find that I have better results, at least with what I am doing, using a 'mix' IR of some kind, vs. a particular mic + placement IR. (Even from the same commercially available cab pack.) That surprised me, as what experience I do have with mic'ing has almost always been an SM57 in front of one speaker in a cab, and that rarely sounds as good to me with this setup.
     

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