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Discussion Starter #1
So I built a full Marty and powered it with a Dayton audio reference 18 woofer. It sounds terrific but at high volume cabinet seems to resonate. I had two braces that run along the length and three that run alone the width. They are joined in the middle. Not sure if this is enough. Also I could not properly attach two front panels together before fixing it to the rest of the cabinet. Instead I had to install one front panel at a time. Although I added lot of glue in between these two panels, I had no way of clamping them together properly.

The cabinet is already painted. How do I determine the exact cause? And what my options of fixing them?

Thank you
 

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I'd start with the easiest thing, stuffing the port. If the sound goes away, it means you might have a port resonance or the resonance is coming from part of the port structure.

If that has little or no effect, take the driver out. Inspect for wires or bracing contacting the back of the driver, forgotten tools or scrap material. Obviously, check that none of the braces are loose.

The driver not being sealed or torqued down properly can introduce noise.

If you're really worried about the baffle layers being loose to each other, you should have room with the driver out to run a couple dozen screws from the inside of the cabinet to pull the layers together.

If you're going to be scientific about it, you'd run sweeps while measuring each panel, panel section, the driver, and the port with a close mic. Ideally you'd do this outside, to mitigate the effects of room modes and reflections. But if it's as obnoxious enough as you noticed it, and it shows up abruptly at a higher volume, it should be pretty easy to spot.

Those Dayton reference drivers can suffer from dynamic offset and go nonlinear when driven to their limit in non-sealed cabs, they tend to make weird noises and distortion when that happens.

Screwing a few pounds of weight to the inside of a resonating panel(section) should drastically lower the frequency of the resonance (and change the amplitude), you could do that to verify you found the offending part.

If you end up wanting to add bracing, I like to use pockethole joinery to clamp while gluing. This way you could add any kind of bracing inside the finished cabinet. Pipe clamps and quick-squeeze clamps are often reversible, so they can spread apart instead of pull together. You can also be clever with driving wedges.

Adding cross bracing is easy, cut two pieces of brace material, each about 25% longer than half the total distance to brace. Put them in place so they overlap in the middle, I like to rotate one 90 degrees so the assembled brace is stiffer against bending in two directions.

Good luck!
 
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I had my mini Marty on my tile floor without anything decoupling the enclosure from the floor and it resonated. I bought some rubber pads from the local hardware store that are made for couches and such, and they did the trick perfectly!
 

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Discussion Starter #5 (Edited)
Very useful info. I will try your suggestions.
Regarding the dayton woofer issue - How can I mitigate that? I am using a inuke6000 DSP, can I use the DSP to mitigate Dayton issue?


I'd start with the easiest thing, stuffing the port. If the sound goes away, it means you might have a port resonance or the resonance is coming from part of the port structure.

If that has little or no effect, take the driver out. Inspect for wires or bracing contacting the back of the driver, forgotten tools or scrap material. Obviously, check that none of the braces are loose.

The driver not being sealed or torqued down properly can introduce noise.

If you're really worried about the baffle layers being loose to each other, you should have room with the driver out to run a couple dozen screws from the inside of the cabinet to pull the layers together.

If you're going to be scientific about it, you'd run sweeps while measuring each panel, panel section, the driver, and the port with a close mic. Ideally you'd do this outside, to mitigate the effects of room modes and reflections. But if it's as obnoxious enough as you noticed it, and it shows up abruptly at a higher volume, it should be pretty easy to spot.

Those Dayton reference drivers can suffer from dynamic offset and go nonlinear when driven to their limit in non-sealed cabs, they tend to make weird noises and distortion when that happens.

Screwing a few pounds of weight to the inside of a resonating panel(section) should drastically lower the frequency of the resonance (and change the amplitude), you could do that to verify you found the offending part.

If you end up wanting to add bracing, I like to use pockethole joinery to clamp while gluing. This way you could add any kind of bracing inside the finished cabinet. Pipe clamps and quick-squeeze clamps are often reversible, so they can spread apart instead of pull together. You can also be clever with driving wedges.

Adding cross bracing is easy, cut two pieces of brace material, each about 25% longer than half the total distance to brace. Put them in place so they overlap in the middle, I like to rotate one 90 degrees so the assembled brace is stiffer against bending in two directions.

Good luck!
 

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Discussion Starter #6
When I place my ear on various panels I get the loudest noise from front two panels.
I already put multiple screws across two panels to connect them together - but issue is still present although it reduced.

Have you tried just running your hands over the panels while it's playing?
 

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You can also make some large gussets withe a concave radius (so it takes up less volume). That will as a lot of panel stiffness and you can do those right behind the driver.

Sent from my Moto G (5) Plus using Tapatalk
 

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Regarding the dayton woofer issue - How can I mitigate that? I am using a inuke6000 DSP, can I use the DSP to mitigate Dayton issue?

What is the Dayton issue?



When I place my ear on various panels I get the loudest noise from front two panels.
I already put multiple screws across two panels to connect them together - but issue is still present although it reduced.

Hard to say w/o knowing what the box looks like.

I'm not familiar w/Full Marty box, took a quick look at several threads but didn't see pic's.
 

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Back I'm the day people used to tap the boxes to get data. You can travel the boxes lightly with a mallet and you should be able to hear any panels that are resonating too much. If you find one you can add a small cross brace to it, which should tame the beast.

Sent from my Moto G (5) Plus using Tapatalk
 

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Back in the day people used to tap the boxes to get data. You can travel the boxes lightly with a mallet and you should be able to hear any panels that are resonating too much. If you find one you can add a small cross brace to it, which should tame the beast.

Sent from my Moto G (5) Plus using Tapatalk
Fixed. Autocorrect -- my favorite!

Sent from my Moto G (5) Plus using Tapatalk
 

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Discussion Starter #12
Thanks for all the suggestions and advice. I was able find the root cause. The driver was loose and just tightening screws fixed it.
@LastButNotLeast I had a 1" layer of foam attached to each panel - except the front panel. I guess I will have to add some padding to front panel as well?
 

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Not if you fixed the problem.
Not that it would do any harm, but there is, apparently, no need.
Michael
 
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