AXE FX discussion continued: speaker break-up?

Discussion in 'Amps and Cabs' started by cg, Jun 30, 2008.

  1. cg

    cg Silver Supporting Member

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    A large part of the sound of amps that I love is speaker breakup. How do you do this with the AXE FX when you are using powered speakers? Are you simulating speaker breakup with the unit itself? I can see how people accomplish this when they are using a guitar cabinet. Not sure how/if people are doing it with powered speakers.
     
  2. Jay Mitchell

    Jay Mitchell Member

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    A lot of players think they're hearing "speaker breakup" when in fact the speaker contributes relatively little distortion to the overall sound. Try playing a perfectly clean PA type amplifier through your favorite guitar speaker and you'll get a pretty good idea just how much "speaker breakup" contributes to your sound.

    There is a drive control in the cabinet sim. I haven't found it necessary, but it's there if you want to play with it.
     
  3. sinasl1

    sinasl1 Member

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    The Axe FX has a parameter in the speaker simulators that allows you to introduce speaker breakup into the sound. Works well, too..
     
  4. Jay Mitchell

    Jay Mitchell Member

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    That's the drive control in the cab sim.
     
  5. Scott Peterson

    Scott Peterson Staff Member

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    Yep, there is a drive control in the speaker sim block. And it works very well.
     
  6. 56_Special

    56_Special Member

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    Yeah, I've often wondered what the fascination with speaker break up was. I have used amps with power scaling and Ho's attenuator and used those same amps in a band situation. I've never really heard a difference that I would attribute to speaker break up as opposed to mere volume.
     
  7. dk_ace

    dk_ace Member

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    Whether or not you guys hear it, speaker break up is real and it definately contributes to the sound. Not nearly as much as some would lead you believe, but it is important for some sounds. I use it frequently in the Axe-fx and have found it immensely useful.

    I feel it more than I hear it sometimes, but it's there. You can certainly get good sounds without it, but it adds just a little bit extra to the sound that I really like.

    D
     
  8. Jay Mitchell

    Jay Mitchell Member

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    I'm interested in hearing how you distinguish between distortion caused by the preamp, the power amp, and the speaker when you're listening to all of those forms of distortion combined.

    Because it isolates only the variable of interest, the suggestion I made above will give you a pretty good idea just how much of a role "speaker breakup" plays in your sound. If you haven't tried it, you haven't yet heard what "speaker breakup" sounds like all by itself.
     
  9. Shiny McShine

    Shiny McShine Member

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    Don't all speakers break up to some extent in that it's physically impossible to produce a square wave in reality?
     
  10. Ed DeGenaro

    Ed DeGenaro Supporting Member

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    It certainly is and does. That said for every guy I've known talking about it I haven't met many that push their cabs enough to make that actually happen.
     
  11. AndrewSimon

    AndrewSimon Member

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    Take a clean Fender preset, hook up your Strat, play.
    Then turn up the speaker drive control, play some more, smile!

    :AOK:AOK
    How? what? why? ..... I don't care... as long as I'm smiling.


    :)
     
  12. cochese

    cochese Supporting Member

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    Probably a good way to hear the difference would be to play a 112 cab with a 25 watt Greenback and then changing to an EV. Also keep in mind that a more efficient speaker like an EV will sound more consistent over a much bigger range of volume than something like a Greenback. I really don't like speaker distortion. It's just one more inconsistent variable in the world of amps.

    I would agree with Ed somewhat. With my THD cab running 2 classic 80's I doubt I've ever made the speakers breakup to any significant degree. When I had my 25 watt Greenback in my Boogie Thiele cab pushed by a 100 watt amp that was another story. Trust me speaker breakup is no fun. When I first started playing Marshall's as a kid I was constantly blowing and replacing those old Celestions. That would be very expensive nowadays.
     
  13. Jay Mitchell

    Jay Mitchell Member

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    There's another wrinkle. The speaker with the higher sensitivity will require less amplifier power to reach a given volume. That means that, for any given playing volume, the power amp will have to be pushed less to drive the higher-sensitivity speaker. In the case of a sensitivity difference of 3dB, the power required would be a factor of 1:2. This will result in substantially more amplifier distortion when driving the lower-sensitivity speaker at a given level. There may be more speaker distortion as well, but it's impossible to separate that from the added distortion from the amp.
     
  14. dk_ace

    dk_ace Member

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    I don't have any interest in speaker breakup in and of itself. I like it in small doses in the bigger picture of the sound. I feel like the amp and cab gel better when you push the speaker just to the point of breakup.

    I also don't like it in all my sounds. I use it a lot on Vox sounds because the alnico speakers being pushed compress the top end a little bit taming that Top Boost harshness. The Axe-fx sim does this as well.

    Ed, I haven't talked to that many people about it, so I can't say how many of the people that talk about it experience it. I can tell you that I've always been a believer in using the right amp for the job, and that means bringing one that I can push until the speakers break a sweat if I want to. If you were directing that at me, I can assure you I'm not one of the guys that talks about stuff he doesn't use.

    D
     
  15. cochese

    cochese Supporting Member

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    In a gig type playing situation this makes sense but if you run an amp (say a 100 watt Marshall at 1/2 volume) into a 15 watt Celestion Blue which has a 100db sensitivity rating and then into a 300 watt EV which also has a 100db rating the Celestion will break up and the EV won't. Still I would agree in most applications it's hard to be certain how much distortion is created by the amp or speaker. Perhaps Fractal did it the scientific way with a scope on a given amp and various speakers.
     
  16. Jay Mitchell

    Jay Mitchell Member

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    That's a different scenario than the one you originally brought up.

    In this new case, assuming the sensitivities of the two speakers are sufficiently close, the differences you hear would indeed be due to the speakers. And the breakup you will hear from the Celestion if you push it too hard won't be pretty (to my ears, at least).

    Here's another important item: the power rating of a speaker has nothing to do with how it will sound at its rated power. Best-case, the power rating is nothing more than the maximum power the speaker can survive without suffering permanent damage. Worst-case, the number can be optimistic by a factor of 2:1 or more.

    The frequency range in which a 12" transducer will "break up" and cause audible distortion is mostly sub-200Hz. Above that frequency, the displacement required to make even very high volumes is quite small, so even pretty wimpy 12s can get loud without producing a lot of distortion compared to what's coming from the amp. A speaker with 100dB/W/m sensitivity will produce 104dB at 2 meters from the cab - a relatively typical playing distance - with just 10 watts from the amplifier. A cabinet with two of the same speaker can make 107-108 dB at the same distance with 10 watts to each speaker. FWIW, that's louder than I ever play. Under these conditions, even pretty cheaply-made transducers won't add a lot of distortion to the sound.

    A Cab sim based on an IR - i.e., the way it's done in the Axe-Fx and other modelers - cannot include speaker-induced distortion in the model. The Axe-Fx has a Drive control in the cab sim which adds distortion, but that distortion isn't specific to the speaker being simulated, it's just an add-on property.

    I use IRs I have taken myself in the Axe-Fx, and I never use the Drive function in the cab sim. It's there if you need it, however.
     
  17. cochese

    cochese Supporting Member

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    I think you are making this more complicated than it has to be. You have the Axe-FX and I don't so obviously you have first hand experience with it's "simulated" speaker break up function. Still as someone who has played tube amps for over 30 years and used non master volume Marshalls at full volume I think I know what speaker break up is and sounds like. A general rule of thumb is that if you want speaker break up you use lower wattage speakers as they will reach their limits sooner than something like an EV or Tonker or JBL. Obviously if you push any speaker too far it probably won't sound good which is why I don't like speaker break up because it tends to be very inconsistent.

    For instance when I had a 25 watt Greenback in my Deluxe reverb years ago it sounded quite good as long as the amp wasn't run past about 1 o'clock. There was a combination of speaker and amp breakup. Once I turned the amp up past that the Greenback just started to crap out. In the same amp I put an EV and the amp was much cleaner even when pushed to the limits because the Deluxe did not have the power to clip that speaker.
     

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