hi
i just want to share with you guys how i just used pink noise and analyzers to set up guitar gear.
i currently working on european festivals with band playing first or second slots on main stages. as we found out 2.5khz is really spiky in the guitars. so as we're having some off days i tried to figure out where this spike comes from.
gear being used guitar wise:
fender twin reverb 65 reissue
lots of pedals, main distortion tube screamer, some reverb and delay pedals.
analyzing gear used:
nti al-1 / analyzer
nti mr pro / noise generator
nti mini spl / measurement mic
plamer pdi / di between power amp and speaker
shortcuts being used:
PN = pink noise
NG = noise generator, mr pro
TS = tube screamer
FIRST first:
(going through the pedals see if there is something that makes the 2.5khz range pop up)
I plugged the NG into the input of the pedal board, tuner in, and the analyzer into the output of the pedal board. i set up a pink noise to check if the bypassed pedals may affect the flatness of the PN. they did not, but good to know.
I went through every pedal in the chain, but left the chain untouched. so basically put each pedal out of bypass and see the change on the analyzer. I pulled every knob from zero to 12 to see how it affects the pink noise, especially the tone knobs, to make sure that they are not broken or maybe cause a bell at 2,5khz.
while doing this i discovered that the tube screamer reacted a little strange on the flatness when i turned the distortion knob up and down. to have a better view of how the distortion affects the signal i switched the NG to "polarity"
polarity is usually used to find phase flips in systems or cables, but it sound like "bap bap bap" so it will give a different reaction on the analyzer when distortion is applied.
and so it did. when i turned the distortion the signal became frequency drops every here and there, and two drops were around 1khz and another one at 3. basically it caused a huge bell at 2,5khz. if you go up to 2 oclock on the TS the signal is not affected that much, but it starts to get really messy at around 3 oclock.
there we got one knob that caused a 2,5khz peak.
SECOND step:
(checking the amp it self)
i tried to find out how exactly the structure of the amp eq is and how the brightness switch works. as well as which position of the eq is flat, or sound fullest by being as flat as possible.
so i put the NG into to fender input (we use the 1st of the reverb channels reverb is switched off) and the analyzer to the di which is between power amp out and speaker to get a flat response not affected by the speaker.
the brighness switch turned out to raise a drastic high shelf peak at around 4khz so it basically raises 2,5 as well. i guess it started around 1khz. the amp was flat and had a nice touch to the pink noise at 5/5/5 (treble, mid, low). not really different from what we've used anyway but we turned off the brightness switch as it was way to much for the PN.
THIRD step:
(checking amp with the pedals)
i ran the PN through pedals and the pedals through the amp to check if something would cause any trouble concerning the 2.5khz range. didn't really change anything, but i equaled out the volumes of all the pedals...
FOURTH step:
(checking amp+pedals with the mic)
the NG was still running pink noise and i attached the mini spl to the al1 instead of the di to check for possible mic positions. amp was as flat giving out the PN as flat as possible. i moved the mic around to see if there are spots that sound very different, i found out that some spots totally peak at 2,5khz and other spots had 500hz as the loudest frequency.
as we had a lack of harmonics (300 to 600) 500hz was more desirable then 2,5khz which we've had an issue with anyway... i turned out that our last position was a position that caused 2.5khz to stick out so we changed the mic position as well.
to my surprise the 2.5khz would appear more at the left and right side of the cab then in the center. so we choose to put the mic in the lower left of the right speaker, about 1,5 inch from the edge of the speaker. noise sounded nice and equal so we checked it with a guitar and it worked fine.
we did this with both guitar rigs and we'll find out on saturday when we have the next big festival show if this is really working or not. but i guess this is a good starting point.
what knowledge did i gain about the bands guitar rig:
# dont use the TS with more distortion then 2 oclock
# fender amps sound better in the center (of the cab not the speaker) then on the edge of the cab
# dont use the brightness switch, get it from the desk if necessary as it boosts like +20 db's in the highs
I will post how it turned out on the festival in a few days
here is a pic of the measurement session:
i just want to share with you guys how i just used pink noise and analyzers to set up guitar gear.
i currently working on european festivals with band playing first or second slots on main stages. as we found out 2.5khz is really spiky in the guitars. so as we're having some off days i tried to figure out where this spike comes from.
gear being used guitar wise:
fender twin reverb 65 reissue
lots of pedals, main distortion tube screamer, some reverb and delay pedals.
analyzing gear used:
nti al-1 / analyzer
nti mr pro / noise generator
nti mini spl / measurement mic
plamer pdi / di between power amp and speaker
shortcuts being used:
PN = pink noise
NG = noise generator, mr pro
TS = tube screamer
FIRST first:
(going through the pedals see if there is something that makes the 2.5khz range pop up)
I plugged the NG into the input of the pedal board, tuner in, and the analyzer into the output of the pedal board. i set up a pink noise to check if the bypassed pedals may affect the flatness of the PN. they did not, but good to know.
I went through every pedal in the chain, but left the chain untouched. so basically put each pedal out of bypass and see the change on the analyzer. I pulled every knob from zero to 12 to see how it affects the pink noise, especially the tone knobs, to make sure that they are not broken or maybe cause a bell at 2,5khz.
while doing this i discovered that the tube screamer reacted a little strange on the flatness when i turned the distortion knob up and down. to have a better view of how the distortion affects the signal i switched the NG to "polarity"
polarity is usually used to find phase flips in systems or cables, but it sound like "bap bap bap" so it will give a different reaction on the analyzer when distortion is applied.
and so it did. when i turned the distortion the signal became frequency drops every here and there, and two drops were around 1khz and another one at 3. basically it caused a huge bell at 2,5khz. if you go up to 2 oclock on the TS the signal is not affected that much, but it starts to get really messy at around 3 oclock.
there we got one knob that caused a 2,5khz peak.
SECOND step:
(checking the amp it self)
i tried to find out how exactly the structure of the amp eq is and how the brightness switch works. as well as which position of the eq is flat, or sound fullest by being as flat as possible.
so i put the NG into to fender input (we use the 1st of the reverb channels reverb is switched off) and the analyzer to the di which is between power amp out and speaker to get a flat response not affected by the speaker.
the brighness switch turned out to raise a drastic high shelf peak at around 4khz so it basically raises 2,5 as well. i guess it started around 1khz. the amp was flat and had a nice touch to the pink noise at 5/5/5 (treble, mid, low). not really different from what we've used anyway but we turned off the brightness switch as it was way to much for the PN.
THIRD step:
(checking amp with the pedals)
i ran the PN through pedals and the pedals through the amp to check if something would cause any trouble concerning the 2.5khz range. didn't really change anything, but i equaled out the volumes of all the pedals...
FOURTH step:
(checking amp+pedals with the mic)
the NG was still running pink noise and i attached the mini spl to the al1 instead of the di to check for possible mic positions. amp was as flat giving out the PN as flat as possible. i moved the mic around to see if there are spots that sound very different, i found out that some spots totally peak at 2,5khz and other spots had 500hz as the loudest frequency.
as we had a lack of harmonics (300 to 600) 500hz was more desirable then 2,5khz which we've had an issue with anyway... i turned out that our last position was a position that caused 2.5khz to stick out so we changed the mic position as well.
to my surprise the 2.5khz would appear more at the left and right side of the cab then in the center. so we choose to put the mic in the lower left of the right speaker, about 1,5 inch from the edge of the speaker. noise sounded nice and equal so we checked it with a guitar and it worked fine.
we did this with both guitar rigs and we'll find out on saturday when we have the next big festival show if this is really working or not. but i guess this is a good starting point.
what knowledge did i gain about the bands guitar rig:
# dont use the TS with more distortion then 2 oclock
# fender amps sound better in the center (of the cab not the speaker) then on the edge of the cab
# dont use the brightness switch, get it from the desk if necessary as it boosts like +20 db's in the highs
I will post how it turned out on the festival in a few days
here is a pic of the measurement session:
