Final advice prior to implementation

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irishpatrick33

Final advice prior to implementation
« on: 7 May 2009, 06:24 am »
Hello,
I have previously benefitted from advice in this forum. Thank you! However, I have two more questions prior to finishing what will be a one of a kind build, sure to cause a reaction.

I have two issues: driver mounting and decoupling methods.

In an attempt not to reveal too much, I might have an issue mounting the driver. I cannot simply screw into the material for fear that the material might break, due to there being such a minimal amount of space between the driver cutout and the mounting holes. Magnet mounting is absolutely out of the question considering that the magnet is absolutely gigantic. I cannot add more mass to the rear of the driver. I once saw a person use rope to mount the driver to the baffle. Does anybody have atypical suggestions.

Also, what are some decoupling methods.

Mr Content

Re: Final advice prior to implementation
« Reply #1 on: 7 May 2009, 11:17 am »
Seems to me, the bigger the magnet, the more sense to magnet mount it. Part of the benefits of magnet mounting, is that you are holding the driver by its greatest mass. I have not seen a driver yet that couldn't be magnet mounted. I am sure it could be done. It would seem to solve your other issues of nowhere to screw the driver to, and decoupling the driver from your baffle.  :thumb:
It may take some vertical thinking, but I dont see any reason why it cannot be done :wink:

Mr C aa

Bob in St. Louis

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Re: Final advice prior to implementation
« Reply #2 on: 7 May 2009, 03:53 pm »
Maybe this will help:
{Photos "borrowed" from the Hawthorne gallery}




irishpatrick33

Re: Final advice prior to implementation
« Reply #3 on: 7 May 2009, 07:35 pm »
Seems to me, the bigger the magnet, the more sense to magnet mount it. Part of the benefits of magnet mounting, is that you are holding the driver by its greatest mass. I have not seen a driver yet that couldn't be magnet mounted. I am sure it could be done. It would seem to solve your other issues of nowhere to screw the driver to, and decoupling the driver from your baffle.  :thumb:
It may take some vertical thinking, but I dont see any reason why it cannot be done :wink:

Mr C aa
You guys ask too many questions. Just kidding.

I am doing my best to ask for advice without spoiling the surprise. Adding more mass to the back of the magnet in my situation is not ideal. It's not a weight issue, but a physicalality issue. On top of that I cannot screw into the baffle material. There I have said too much already and will be arrested.


Decoupling materials?

Bob in St. Louis

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Re: Final advice prior to implementation
« Reply #4 on: 7 May 2009, 09:17 pm »
Decoupling materials?
Constrained layers of dissimilar material with "Green Glue" in between.

Gee. I'm looking forward to seeing photos of your project.
I take it you don't like the recommendation of the wooden "vise"?

Bob

xyr

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Re: Final advice prior to implementation
« Reply #5 on: 8 May 2009, 03:12 am »
I take it you don't like the recommendation of the wooden "vise"?

I don't like it, it looks like it's obstructing the driver too much. :)

btw, I use rope mounting.

Mr Content

Re: Final advice prior to implementation
« Reply #6 on: 8 May 2009, 06:52 am »
If you are laminating different materials together, I have found that some of the rubber compound tile glues are very good for this. I use "tile on timber" and this product will stick to most substrates, and WONT let go. Being rubber based gives it good isolation properties :thumb:

Mr C :wink:

Paul W

Re: Final advice prior to implementation
« Reply #7 on: 8 May 2009, 01:38 pm »
You could use something to clamp the driver to the baffle outside the normal mounting pattern...like cable clamps ground down to points that would fit into the driver mounting holes.  Or, a "baffle behind the baffle"...mount the driver to the sub-baffle and mount that to the main baffle...or float the sub-baffle on a large layer of felt.  Not sure what you are trying to accomplish.

irishpatrick33

Re: Final advice prior to implementation
« Reply #8 on: 9 May 2009, 02:39 am »
I take it you don't like the recommendation of the wooden "vise"?

I don't like it, it looks like it's obstructing the driver too much. :)

btw, I use rope mounting.

You are the man I was referring to. The more I think about it the more I believe I will have to attempt something similar.

irishpatrick33

Re: Final advice prior to implementation
« Reply #9 on: 9 May 2009, 02:56 am »
Alright, I have decided upon the driver mounting. Thanks for the input. One of the problems with gluing is that I will not be able to take things back apart in the future. I must be able to disassemble and change things as needed.


Now I still have the decoupling materials question. What are some good ideas? Dynamat?

XYR also did something that makes me wonder if I should do the same. He has some dampening material on the magent. Good idea or so so? What materials should be used?

xyr

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Re: Final advice prior to implementation
« Reply #10 on: 9 May 2009, 12:13 pm »
You are the man I was referring to. The more I think about it the more I believe I will have to attempt something similar.
The credit goes to scorpion, I saw his mounting method here.

In my opinion, choosing the right decoupling material here is critical -it should absorb woofer induced baffle vibrations and in the same time act as a stiff material for my mid induced ones. To complicate things a bit further -the rope is also a part of the decoupling system.

Unfortunately I don't know which is the right combination of materials to use here -I'm still experimenting. I used a spongy material they use in hardware packaging and a thick string, but it's too soft -baffle vibrations are gone, but my mid kicks like a mule. :) I'll have to try something else.

On the other hand If I had the money for a massive chunk of granite (or something like that), this would not be my preferred mounting method.

Dampening material on the magnet (& basket) is a variant of the well known bluetack, and I'll soon double the amount of it. People on diyaudio have used different materials here, and bluetack is confirmed to be very good for this purpose. Not only can you kill the ringing and mechanically strengthen the chassis this way, you can also improve aerodynamic properties of your driver. The felt cap on the magnet is supposedly helping with reflections and is just a small detail in the big picture. As you see on the photo, my speakers are still WIP.