HELP! Resonant Frequency Issues!

[jrsongs]

Hoping someone can help me with this. Although I’ve been recording demos in my bedroom studio for a while, I’m new to recording acoustic guitars.

This week, while trying to record my “best acoustic” (an old Canadian made Garrison) I came across an issue of what I can only guess to be resonant frequencies. To my ears, it actually sounds like the guitar is feeding back. I’m recording in a small, decently treated room with wooden floors and nine 2’ x 4’ four inch thick bass traps. My mic for this application is an awesome Telefunken 251 clone that was made here in Nashville.

This morning, I took my guitar to a local shop, which said that they couldn’t hear the problem I was describing. To be fair, it was loud in the shop and the problem only became noticeable to me after compressing/ doubling the part. The two most offensive frequencies are at around 930 hz and 740 hz. I’ve recorded the same sound with varying degrees of mic signal, varying distance from the mic, and different headphones (I thought spillage might be the cause of the issue).

I know this issue isn’t just in my head, I CAN hear it. Is this just a problem with all acoustics? Is it just my guitar? Does this point to a problem with my room? I’m very frustrated as my cheaper Martin sounds like crap, but doesn’t have this issue.

I’ve posted a terrible clip copied/pasted a few times in the attached file so you can hear what I’m describing. I really do appreciate any help you can offer.

Thanks!

Jonathan

[jrsongs]

Since posting this originally, I've tried a different room, 2 additional mics, and an additional set of headphones (to rule out feedback from headphone bleed), and nothing has solved my problem. I'm guessing it's the guitar.

If it is, is this fixable? Or just an aspect of the instrument to learn to love?

[sdelsolray]

After recording, try putting an eq plugin in place in your DAW with notch filters for those two frequencies. Then listen to the playback.

[KevWind]

Originally Posted by jrsongs

Hoping someone can help me with this. Although I’ve been recording demos in my bedroom studio for a while, I’m new to recording acoustic guitars.

This week, while trying to record my “best acoustic” (an old Canadian made Garrison) I came across an issue of what I can only guess to be resonant frequencies. To my ears, it actually sounds like the guitar is feeding back. I’m recording in a small, decently treated room with wooden floors and nine 2’ x 4’ four inch thick bass traps. My mic for this application is an awesome Telefunken 251 clone that was made here in Nashville.

This morning, I took my guitar to a local shop, which said that they couldn’t hear the problem I was describing. To be fair, it was loud in the shop and the problem only became noticeable to me after compressing/ doubling the part. The two most offensive frequencies are at around 930 hz and 740 hz. I’ve recorded the same sound with varying degrees of mic signal, varying distance from the mic, and different headphones (I thought spillage might be the cause of the issue).

I know this issue isn’t just in my head, I CAN hear it. Is this just a problem with all acoustics? Is it just my guitar? Does this point to a problem with my room? I’m very frustrated as my cheaper Martin sounds like crap, but doesn’t have this issue.

I’ve posted a terrible clip copied/pasted a few times in the attached file so you can hear what I’m describing. I really do appreciate any help you can offer.

Thanks!

Jonathan

Well if you are sure that the problem frequencies are 740 hz and and 930 hz then I would suggest that you use an adjustable multi band or two single band EQs before the compressor and do a narrow Q cut at 740 and 930 starting at about -4 db and keep going down until you get a desired result.

I don't know a "resonant frequency" But all acoustic guitars and human voices have "problem frequencies" and usually they are closer to an octave apart so so 740 an 930 are a bit unusual but I suppose it could just be that guitar and or guitar mic combo.
Anyway a narrow cut centered on the problem frequencies should help .

[Andy Howell]

Yep - just notch them out. There's nothing unusual about this especially when close micing in a small space.


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[rick-slo]

That chord had a ringing F# (370 hertz) at the top. Double that is 740 hertz. For that frequency anyway it could be a prominent over tone and/or sympathetic vibrations.

[endpin]

My Taylor guitar has a "wolf tone" about F# - most musical instruments have them - it's not that uncommon.

[rick-slo]

More careful analysis of the clip you provided does not show a problem with the frequencies you mentioned. However the recording is quite hot with numerous overs. Below is a snap shot of a fifty band frequency spectrum of the recording:

[Rudy4]

When I play the clip I get weird "stutter" in the audio (as demonstrated around 10 seconds).
If that's what you're referring to that would be a problem with your recording hardware setup, unless it's caused from a bad copy/paste of a segment.