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Topic: Harmonics vs. Fundamentals...help! |
Patrick Janka
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Posted 10 Nov 2011 11:04 am |
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| When I play diads/chords on the upper frets of the upper strings I get some sub harmonic frequencies that drown out my fundamental notes. Is there a way around this? Do I need to re-EQ my amp? It sounds nasty, and I don't seem to hear it on records. |
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Steve Collins
From:
Alaska, USA
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Posted 10 Nov 2011 2:26 pm
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| are you muting the strings behind the bar? |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 10 Nov 2011 2:27 pm
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What you are hearing is harmonic distortion generated by overdriving some stage or stages of the signal chain. If you slide up or down these harmonics often can be heard going in the opposite direction, some reverb circuits go bonkers trying to reproduce such a complex signal.
Most "guitar" amps and speakers are designed to do this on purpose, this is why so many steel players use high-power amps with high-fidelity speakers and so many threads on the forum are about various means available to get adequate volume with a rich, articulate sound. If this happens to me I will:
1) Turn down, either at the amp or the VP, until the problem goes away. If no joy is in this...
2) Turn down the lows at the amp until the problem goes away. If still no joy...
3) Turn off the reverb at the amp, and remove - do not simply "bypass" but REMOVE - everything between the VP and the amp, as well as all effects loop connections. We want to hear nothing but guitar > cable > VP > cable > preamp > power amp > speaker. If this fixes it then I would begin re-inserting the various extra toys one at a time back into their places in the chain until the culprit is found. Very often distortion issues are traced to an inexpensive tuner patched into the system that is compromising the integrity of the signal. But, if still no solution is yet found to this problem
4) Try the existing amp with a known good, high fidelity speaker in a decent cabinet - Ken Fox and others here have had good results and can make some recommedationa regarding new technology designs but for sure most any good BW or JBL speaker will provide a dependable benchmark for this purpose. Celestion and Eminence speakers that come with many guitar amps are designed to "shred" at low power levels and it sounds just like what you describe. If playing the existing amp through a "clean" speaker still reproduces this harmonic artifact then
5) You are looking for more clean power than your current amp system can provide, period. It is time to get the band to turn it down or start trying your rig through other amps, having the long talk with significant others and saving your pennies to buy the one that works for you....
Last edited by Dave Grafe on 10 Nov 2011 2:41 pm; edited 3 times in total |
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Steve Collins
From:
Alaska, USA
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Posted 10 Nov 2011 2:31 pm
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| are you muting the strings behind the bar? |
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Bob Hoffnar
From:
Austin, Tx
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Posted 10 Nov 2011 2:37 pm
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You are most likely over driving your input. If you are using a Fender amp try the attenuated second input. Or you can bring down the level of signal going into the amp by lowering your pickup or buffering your signal. It is a very common issue that is an easy fix.
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Bob |
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Patrick Janka
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Posted 10 Nov 2011 4:13 pm
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| Yes, I'm muting behind the bar and not placing the bar on any strings higher than the ones I'm playing. I'm playing through a 100W (with a 50W switch) Mesa Boogie Lonestar 2x12 tube amp. I'm not at home, but when I get back I'll try the suggestions mentioned. |
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Bob Hoffnar
From:
Austin, Tx
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Posted 10 Nov 2011 5:13 pm
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I'll bet dollars to donuts your problem is you are hitting your input/pre amp section too hard with that amp. I did quite a bit of research on the "difference tone" issue. Easy fix.
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Bob |
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mike nolan
From:
Forest Hills, NY USA
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Posted 10 Nov 2011 8:15 pm
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| I don't know how many donuts you can get for a dollar these days..... but I'm with Bob. You really have to watch the gain staging when using any Mesa Boogie with PSG. They like to distort. |
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Patrick Janka
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Posted 10 Nov 2011 9:09 pm
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| mike nolan wrote: |
| You really have to watch the gain staging when using any Mesa Boogie with PSG. They like to distort. |
That's odd you say that because it's one of the cleanest amps you can buy for guitar. I play my Tele through it, and it's crystal clear regardless of volume. Then again my Tele has low output single coils, and my steel has humbuckers. I'll mess with it in the morning. |
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