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Discussion Starter · #1 ·
So, I know that I don't know anything about lining already....... :bigsmile:

What is the best way to attach acoustic fiberglass to MDF? Trying to finish a couple projects (will post build threads...) and having a terrible time. I've tried a couple spray adhesives, including 3M 80 which is super sticky..

I haven't tried PL glue / liquid nails - but doubt that it would work much better. I don't think that staples would hold well either?

I've seen various solutions for mounting to a wall, but I don't think they're appropriate. Friction fitting works to SOME degree.
 

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Discussion Starter · #2 ·
Yay for insomnia....!

I tried PL glue and works very well.

The problem with the spray adhesives is that they have a setup time of a few minutes, so they don't have enough initial tack........ and the spray doesn't have much volume.

The stickiness of PL and the volume of it (more of it to STICK to the fiberglass) seems to work much better.
 

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Discussion Starter · #5 ·
Thanks guys! I knew someone would give some recommendations.
Funny, I almost bought some 74 the other day.

I would have tried staples if I had my staple gun handy. Glad to know that works!

I thought that acoustic fiberglass would be nicer to work with than pink fiberglass - and honestly I've been surprised at how fibrous and messy acoustic fiberglass is. Much shorter strands and more likely to shed.
 

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Everybody's secret is using polyfil pillows and just stuffing the pillows in the box. Works great and the pillows are wonderful on sleep music . . . . :)
 

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Discussion Starter · #7 ·
Everybody's secret is using polyfil pillows and just stuffing the pillows in the box. Works great and the pillows are wonderful on sleep music . . . . :)
I've heard that for stuffing.. but not for lining.

I thought about doing that for a sealed build, but polyfill was a lot cheaper than pillows..
 

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If there's ANY doubt in your mind that you may have to ever open the box for whatever reason and make changes to wiring, driver, amp, terminals, X-0ver, etc, it sure is nice and easy to just pull out a pillow or two and make the changes . . . . and then put the pillows back when you're done.
PLUS you never have to worry about any of the polyfil dropping/sagging into the magnet, voice coil, or suspension.
 

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Discussion Starter · #9 ·
When you're making quick changes, do you just leave the driver resting on the enclosure?

For some reason, I really hate screwing/unscrewing drivers. Just trying not to cross thread.. or tear out the hurricane nuts.
 

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Taking into account that you may have to re-enter the box, I've always considered making sure the screws and or bolts can be removed without creating a disaster.
My last sub-box, I used bolts with T-nuts carefully pre-drilled into the MDF and then epoxied them in place making sure no epoxy got into the threaded portion of the nut. Prior to installation I made sure that each of the 8 (stainless steel) bolts screwed in AND out with little or no friction, adding a tiny bit of "Permatex" anti-seize lubricant to each bolt. Then, at the point of installation, I used a minimum amount of torque to tighten the bolts, only enough to satisfactorily seal and hold the driver to the MDF.
I have NOT had to re-enter my last sub box so far.
If I did have to re-enter the box, YES, I would remove the driver. The driver in my case is an expensive item. I don't want to take a chance of damaging it. The driver is also heavy, 85 Lbs. It's much easier to move and position the box for servicing without the driver attached. And the final consideration is accidental damage to the driver. Even though the most fragile piece on my driver is the titanium cone and advertised to be able to withstand the weight of a man standing on it, I'm not about to test the veracity of that bit of bravado. The less screwin around you do with the driver, the longer it can last. Remove the driver and put it out of the way to avoid damaging it. I've learned the hard way. Re-coning an 18" driver is NOT cheap. Even a small hole, un-repaired can change the T/S parameters of the driver.
On smaller boxes with smaller lighter weight drivers, I'll use wood screws. But even here, if you've got a lot of experimentation to do with interior parts or the tweeter/mids wiring and capacitor changes in the X-over, the threads in the wood will only withstand so much screw in and screw out and tightening. Be prepared to do a little screw hole repair and re-drill if necessary.
 

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Discussion Starter · #12 ·
Thanks for your comments.. I used screws the last time I mounted 12" woofers, but generally use socket head screws and hurricane nuts from PE for anything bigger.

The idea of anti-seize lubricant is BRILLIANT.

I should start doing that.
 

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By the way, Chester, I looked at all your pictures . . . . . and want to know, How does it all sound?
You've got yourself a lot of MTX (61/2" ?) duals in the ceiling plus a SUB on the floor.
Is it good for movies, music, . . . . what?
What's in that sub?
Or is all the info in a thread somewhere else?
 

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Actually those are 8" mtx speakers (HR824c), the sub is some old (cheap) X-site XS1580 (Audiobahn sub-brand I believe) I built 8 ish years ago :)

I measured all of the speakers and EQ'd them with REW (I did a near-field measurement on each speaker). and have ~8 parametric eqs per channel with the Crown USM-810 processor.

apart from more needing a bit more environmental adsorption, it sounds excellent. We play the radio (Tascam TU-690), cd/hard drive (Numark HDCD1), and ipod (1/8" jack) into the system which is mixed with a Shure Auxpander (8x8 matrix mixer) to route things to various rooms: amplifier is a Crown CTS-8200

https://picasaweb.google.com/104397511504855984040/InHomeStereo#5394111976551595858

If I were starting from scratch

As far as the equipment goes:
Tascam TU-690: excellent radio... hard to mess up a radio though :) I wish the remote worked a bit further, only goes ~15 feet.

1/8" jack: I got it at Radioshack, it performs as expected :) We plug computers/ipods/sansas in here.

Numark HDCD1 - don't get this, it has an 80 gb hdd in it with 2 cd drives, it *looks* cool, however the interface is quite slow and it can only transfer in usb 1.1 mode (12 mbps) so it takes a very long time to upload music on there. Also it takes a little while for it to boot up... overall I just don't like the HDCD1. The fan in it was a bit noisy till I put a resistor in series with the fan (I.E. if you buy one, it will sound like a jet unless you want to mess with it)

Shure Auxpander: very cool, balanced/unbalanced 8x8 matrix mixer (after entering the Auxpander, all audio is balanced), the channels are well matched (8 o clock on one channel is the same level as 8 o clock on all of the other channels)

Crown USM-810: awesome. 128 bands of parametric EQ divided across 8x10 channels, which allows me to apply my house curve of 7 parametric eq's to each channel, eq each speaker (or in the kitchen the average of 2 speakers on both channels) with 8 bands of parametric eq each. Also allows me to output two sub channels which is handy (it also does crossover filters and shelving filters though I usually just use parametric): we have a usm-810 on our tv also.

Crown CTS-8200: Ch 8x200 watts amplifier class AB amp, works great, the channels are actually in modular 'cards' that plugin to a main board (if you were to open the amp up), so if a channel goes out you can just replace one card as opposed to the entire amplifier, the amp has variable speed fans in it though they can be a bit loud at times (if you are right next to it). Overall fan noise is not too bad on the amp, the HDCD1 is way worse :) (we also use one of these on our tv)

Basically the system is just for listening to music/radio at home, potentially we will hook a tv up to it someday if we put a tv in the kitchen...

hope that explains it!

EDIT/note: if you look at the album as opposed to just the pictures I posted you will see more :)

https://picasaweb.google.com/104397511504855984040/InHomeStereo#

second edit: my whole picasa album is speaker/sound stuff too

https://picasaweb.google.com/Chesteta
 

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Excellent explanation for a 1-off system. I'm impressed.
I wonder how much additional "detail" you might get with more sound deadening in the listening area. Or is there NO listening AREA perse'?
 

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There is not really a listening area, it is wherever anyone happens to be that wants to listen to music :)

I setup things to be more towards the center of the room, the HR824c's have dome tweeters that can be rotated, I took and measured from the center of the room out a given distance (and marked it on the floor) and used an old laser pointer which I attached to the dome tweeter in order to aim the tweeters.

When I measured the speakers I put the microphone so that it was on axis with the tweeters and ~1 foot away, since there is no listening area, I figured I would make the speakers frequency response as flat as I could (since the room response will change depending upon where one is positioned).

This shows the original responses in REW and the 'next' picture (if you click next) will show the predicted response.
https://picasaweb.google.com/104397511504855984040/REW#5406607856436997922
 

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The curves look real good, maybe somewhat "bright" in the 4K to 7K Hz region but that's the way I prefer them.
Without straying too far from poster's thread, I see you glued the fiber fill behind the MTX and also had some labeled plastic behind the drywall. Was that an enclosure?
 

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Correct, I glue rockwool inside of all of my speakers with the 3M 74 stuff however the ceiling speaker pictures were the best to demonstrate the 74 stuff: also it is key to let the solvent dry out for a minute or two (as you would with a contact cement), forgot to say that before, but it does say that on the side of the can :)

the plastic behind there was the enclosure, they are ~1 cu foot enclosures, made by a company called backboxx (i believe), they are just plastic enclosures: we have a 1" polyurethane water vapor barrier foam that has been sprayed in the ceiling though so it is pretty rigid: I also put activated charcoal up there too with the idea of 1) adding some mass to keep the drywall from flexing/resonating so much and 2) slowing air flow down/killing standing waves in the enclosure.
 

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Interesting installation and choice of equipment and materials. Yup, you're a DIYer.
Imagine trying to explain to a union electrician what you wanted to do and why?
It'd never happen, nope not in the book.
 
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