Sound hole cover (anti feedback) for slightly smaller sound hole?

BothHands · #1 08-28-2016, 04:37 PM

I have an Alvarez MD series guitar with what turns out to be a smaller-than-normal sound hole. Average sound holes seem to be 4" and larger.

My diameter is just slightly smaller at 3-7/8" and I've not been able to find an anti-feedback sound hole cover for it.

Does anybody know of one that will fit?

chitz · #2 08-29-2016, 05:40 AM

I've only seen the one offered by planet waves that fits most dread models.

You may have to fabricate one.

benderman57 · #3 08-29-2016, 05:55 AM

Other than fabricating one yourself the only option I know of out there is a custom made Lutehole. They work well and look neat but be prepared to spend around $90 to get one made.

curbucci · #4 08-29-2016, 07:45 AM

Did you try a classical guitar soundhole cover?

http://www.cordobaguitars.com/p/soundhole-cover

craigj · #5 08-29-2016, 09:03 AM

I took an Exacto knife and sliced out a very thin "piece of pie" from a Planet Waves one for my Larrivee. Then you can press it together to fit the soundhole without forcing it.

kaos · #6 08-29-2016, 09:28 AM

Quote:

Originally Posted by craigj

I took an Exacto knife and sliced out a very thin "piece of pie" from a Planet Waves one for my Larrivee. Then you can press it together to fit the soundhole without forcing it.

I was thinking of doing this. I am glad you posted that it works. Did the pie slice go all the way to the center?

Ruppster · #7 08-29-2016, 09:50 AM

For my Takamine parlor I trimmed a regular feedback buster to fit. I did not touch the outer, thinner edge. I took some garden shears and trimmed the edges of the inside without cutting all the way through the FB. It didn't look great but it did the job and, when it was in, you couldn't tell the difference.

BothHands · #8 08-29-2016, 10:44 AM

Quote:

Originally Posted by chitz;

You may have to fabricate one.

Thanks, and yeah. I'm sure I could make one if I truly understood which design aspects make a sound hole cover work well:

1. Is it reliant on a perfect seal around the circumference of the sound hole?

2. Is it reliant on the thickness of the "wall" material that spans the sound hole?

3. Is it reliant on the density (weight) of the material that spans the sound hole?
Those Planet Waves units are made from a heavy/dense black rubber.

I could easily make a 4-1/4" disk from 1/8" masonite (hardboard) and glue a 3-7/8" foam disk to its back surface. The foam would fit into the sound hole and hold the unit in place.

BUT...is the masonite dense enough to stop the air movement (vibrations) that otherwise enter the guitar body and cause feedback? And if the backing foam is open-cell vs. closed-cell, will the open-cell material do the job?

I don't know. Do any of you?

BothHands · #9 08-29-2016, 10:45 AM

Quote:

Originally Posted by benderman57

Other than fabricating one yourself the only option I know of out there is a custom made Lutehole. They work well and look neat but be prepared to spend around $90 to get one made.

Thanks. Yeah, $90 is not going to happen...

BothHands · #10 08-29-2016, 10:47 AM

Quote:

Originally Posted by curbucci

Did you try a classical guitar soundhole cover?
http://www.cordobaguitars.com/p/soundhole-cover

Thanks, but that one's 86mm which is too small for my guitar. It's always something, right?

BothHands · #11 08-29-2016, 10:50 AM

Quote:

Originally Posted by craigj

I took an Exacto knife and sliced out a very thin "piece of pie" from a Planet Waves one for my Larrivee. Then you can press it together to fit the soundhole without forcing it.

I'm surprised. If I read you correctly, your pie cut removed a wedge from the face of the unit - the material that spans the sound hole. I would think it necessary to maintain a solid continuous surface there (no holes).

Is there actually a gap in the rubber material that spans the sound hole?

BothHands · #12 08-29-2016, 10:53 AM

Quote:

Originally Posted by Ruppster

For my Takamine parlor I trimmed a regular feedback buster to fit. I did not touch the outer, thinner edge. I took some garden shears and trimmed the edges of the inside without cutting all the way through the FB. It didn't look great but it did the job and, when it was in, you couldn't tell the difference.

What's the diameter of your Takamine sound hole? I considered placing a Planet Waves unit face-down on a turntable and grinding the inner/rear/smaller circumference (the part that fits into the sound hole) so as to make the diameter smaller. But I wasn't sure the material would grind off, and wasn't sure how thick the material is at that point. Might not be enough rubber there to allow reducing the diameter to fit a 3-7/8" hole.

craigj · #13 08-29-2016, 11:27 AM

Quote:

Originally Posted by kaos

I was thinking of doing this. I am glad you posted that it works. Did the pie slice go all the way to the center?

Yep. That's where I started.

chitz · #14 08-29-2016, 06:10 PM

It does not need to be a perfect seal, or any particular thickness.

Almost anything will keep ambient sound from entering the hole.

Ruppster · #15 08-29-2016, 06:11 PM

Quote:

Originally Posted by BothHands

What's the diameter of your Takamine sound hole? I considered placing a Planet Waves unit face-down on a turntable and grinding the inner/rear/smaller circumference (the part that fits into the sound hole) so as to make the diameter smaller. But I wasn't sure the material would grind off, and wasn't sure how thick the material is at that point. Might not be enough rubber there to allow reducing the diameter to fit a 3-7/8" hole.

I keep the guitar at the office so can't tell you offhand. I'll try to remember to take a tape measure with me to work tomorrow. I can tell you that the FB was surprisingly thick so I think this would work for you.

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