3/31/2011

Fletcher–Munson curve and the amp simulators

I wish this would be the title of my band's new record but I suppose my bandmates wouldn't be very happy...

Alright... WTF???


This is the Fletcher-Munson chart created by...er...Harvey Fletcher and W. A. Munson in 1933. They probably weren't guitar players but they sure did us all a big favor in 1933, when they came up with this.

They noticed that the way we perceive the sound is different depending on how loud is the sound. Imagine you have a CD player and you slowly turn up the volume. Same CD, same song, same stereo, same everything but the volume. Notice how the bass and treble frequencies start to bloom out and the mid-range frequencies kinds stay the same. This is basically it!

And what does this have to do with POD's and such? Because they can mislead us into a VERY dangerous trap. Ok, not very dangerous but a trap that can make your audience think they are listening to a bee hive, a plane turbine, a dog fart and not a guitar.

People who have amp sim's usually set up their patches before the concert, at home, at a very low volume, so the neighbours don't call the cops and the family doesn't go nuts. When they get to the rehearsal or the show, the once gorgeous, full of life, mid-scooped, heavy and awesome guitar tone sounds like... poop.

Yesterday was my first successful attempt to plug the POD HD500 directly into the desk. I asked my bad mates for 5 minutes to set it up and was ready to go! When I got home and listened to my patch on my headphones, it sounded like crap! Middy, muddy, lifeless and boring. It was supposed to sound like that and I was even expecting it to sound like crap.



Since it's a digital unit, you get the same sound no matter how loud you turn up the volume but the way you perceive it is very different. The low end was really tight, the mids were there, but more focused and the highs were sparkly enough to rival with the drum cymbals.

I used to bring my own amp to rehearsal because i never had the patience to set the tone at the studio and every time I came up with something that sounded good through headphones, ended up sounding terrible at the practice. This made my life a lot easier because now I only have to bring the POD and the guitar to the studio to have a decent sound!


And why th f*** this doesn't happen to tube amps? Simple! The louder you turn the volume on the amp, the more the power tubes saturate and the more speaker breakup you have.
Power tubes saturation = more low mids.
Speaker breakup = more highs.

Here is the link to the patch I made to play yesterday. It's a good Idea to set the choruses, reverbs and delays prior to the gig to save time and leave the amp/cap settings to be made with the band, with the PA you will use and at the volume you will play. If you know you are not going to have time to do this, set it up at home and remember you have to come up with a dull, lifeless and overmiddy sound.

Here's the patch I used last night. Hope this helps many guitarists who rely only on the POD's to get their tones and always end up buried in the mix!

1 comment:

  1. Dude,
    Check this article:
    http://www.soundonsound.com/sos/jun02/articles/monitors.asp

    It has some nice information about frequency range that might be useful.

    ReplyDelete