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fEARful part nine (9)

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#642
WC:

I peeled some unfaced "attic" batts of r30 I had lying around in half and am liking the way it worked out [+/- r15 = +/- 4" ???]- so unfaced batts of r13 would probably be fine - r11 if you like a more modestly damped cab - I would reckon r13 is a bit more damping than a double layer of poly batting with a flatter attenuation curve across the mids down to the "hi-lows".

And whatever you do heed the Green Man and stay out of the way of the port - the spice must flow!

BTW - if any of you guys have used or abused the line 6 g30 wireless I would appreciate a thumbs up/down - am looking for a reliable full bandwidth wireless so I can saunter over & bitch slap the sound man without having to drop out of the pocket. TIA for any PM's on this off topic query.
 
#644
1) The requirements for a larger, longer cab are not always what is needed for a smaller one.

2) The midrange chamber itself really changes the equation. Remember the web pages.

3) I've replaced fiberglass in quite a few cabs, and just layered polyfill batting of the thicker "sleeping bag" variety, tuning to ear.

4) Poly batting is usually available at Jo-Ann Fabrics by the counter where the gorgeous brunette with the stunning smile works. In contrast to the guy in the insulation department at Home Depot.

20100122_apes_250x375.jpg


The choice is clear.
 
#645
Fiberglass is fine though. I used to use actual acoustic fiberglass, which is denser and thus needs to be less thick. I just won't recommend it any more becausee so many people are irritated by it and some wonder about the long term effects.

***

Group buys won't happen. Not unless policy is changed. I revisit this issue from time to time. I'm sure Eminence wants OEM buyers who are builders to feel they have an edge.
 
#646
wonder about the long term effects
Click to expand...

Largely mythical... If you want to use something else that's fine by me - and if you say polybatts can work well, I believe ya [though IME the thin layers of this and/or random foam in my cabs was not doing the job - I'll concede that if done differently I might have found them adequate].

But please, let's not pretend fiberglass is scary dangerous - it aint.

The HVAC system in damned near every building in the world blows through fiberglass lined ducts & the ceilings tiles in damn near every commercial building in the word are made of friable fiberglass. If it made you sick, you'd be sick. If it could kill ya, you'd be dead. And the same is true for everyone else living above the "mud hut" level of civilization.

Generally exposure to the other materials and fumes involved in a fEarful build [sawdust, glue, paint & solder] pose more of a potential health risk than fiberglass because given long term high volume exposure there are real carcinogenic risks in addition to respiratory risks.

Invalid Link Removed

But that is not to say I think speaker building is particularly dangerous in that regard... rather I am trying to convey that 10 minutes of batt stapling would represent an inestimably small % of your exposure to the material over your lifetime and is not going to effect your health.

Sorry for the rant - but the idea that fiberglass batts are dangerous has way to much influence across the innertubes.
 
#647
Foz said:
WC:

I peeled some unfaced "attic" batts of r30 I had lying around in half and am liking the way it worked out [+/- r15 = +/- 4"]
Click to expand...

Sounds about right since an R-30 batt is 9-1/2" thick.

I'm using unfaced R-19 that I'm going to peel down. I'm guessing about 4" thick should be about right.

I think I'm going to do the hard to reach spots before I put the back. Like the back of the mid chamber and upper baffle and sides towards the front. Any reason to do the underside of the top panel?

I'm going to try using spray adhesive with the Fiberglas batts.
 
#649
Foz said:
Sorry for the rant - but the idea that fiberglass batts are dangerous has way to much influence across the innertubes.
Click to expand...

The link you posted definitely suggests otherwise Foz, but your points are still well taken. In any case, I am very allergic and would not remotely consider touching it without using gloves and a respirator. I did in fact get sick any time I repaired cabs insulated with glass batt, so there you go. Maybe that's why HVAC bugs me so badly too. Your point about other stuff being worse is valid (check out the MSDS on spray-on adhesive, for instance) and is one reason I am no longer going to do DIY cab builds. Time to pick some other poison, I guess. ;)
 
#650
WCunha said:
Here's another picture. I don't know if it will be easier to see. This is the one I sent Jim.
Click to expand...

I think you've had confirmation already, but it looks good to me, with the caveat that the pic is pretty low res, but assuming the lines do what I think they do, and the component values are correct...
 
#651
Foz said:
Largely mythical... If you want to use something else that's fine by me - and if you say polybatts can work well, I believe ya [though IME the thin layers of this and/or random foam in my cabs was not doing the job - I'll concede that if done differently I might have found them adequate].

But please, let's not pretend fiberglass is scary dangerous - it aint.

The HVAC system in damned near every building in the world blows through fiberglass lined ducts & the ceilings tiles in damn near every commercial building in the word are made of friable fiberglass. If it made you sick, you'd be sick. If it could kill ya, you'd be dead. And the same is true for everyone else living above the "mud hut" level of civilization.

Generally exposure to the other materials and fumes involved in a fEarful build [sawdust, glue, paint & solder] pose more of a potential health risk than fiberglass because given long term high volume exposure there are real carcinogenic risks in addition to respiratory risks.

Invalid Link Removed

But that is not to say I think speaker building is particularly dangerous in that regard... rather I am trying to convey that 10 minutes of batt stapling would represent an inestimably small % of your exposure to the material over your lifetime and is not going to effect your health.

Sorry for the rant - but the idea that fiberglass batts are dangerous has way to much influence across the innertubes.
Click to expand...

I just don't like working with the stuff. I've had too many uncomfortable days and nights as a kid from installing fiberglass insulation. When I was building and finishing my cab in summer temperatures the thought of suiting up to do it was more than I wanted. The poly batting double or triple layered worked fine for me and was quick and easy to use without much in the way of precautions.
 
#652
BurningSkies said:
I think you've had confirmation already, but it looks good to me, with the caveat that the pic is pretty low res, but assuming the lines do what I think they do, and the component values are correct...
Click to expand...

I took the pic with my iPhone.

The resistors were what GB specified before he switched the specs on the wire wound resistors.
 
#653
Itchy crap vs not itchy crap, that's the question. Fiberglass insulation is raspy, nasty stuff. Mess with it for a few minutes and the sparkly shards will be floating in the air for hours. It irritates eyes, throat, and skin, you really don't want to breathe it, even if it won't kill you.

I'll go non itchy, and be glad every time I reach in the cab to make changes. A bargain at three times the price of itchy.

I was pleasantly surprised at how mellow the Duratex turned out to be. No stinky fumes, easy cleanup, quick drying.
 
#655
singlemalt said:
Itchy crap vs not itchy crap, that's the question. Fiberglass insulation is raspy, nasty stuff. Mess with it for a few minutes and the sparkly shards will be floating in the air for hours. It irritates eyes, throat, and skin, you really don't want to breathe it, even if it won't kill you.

I'll go non itchy, and be glad every time I reach in the cab to make changes. A bargain at three times the price of itchy.

I was pleasantly surprised at how mellow the Duratex turned out to be. No stinky fumes, easy cleanup, quick drying.
Click to expand...


Yeah, Duratex is very easy to be around and I like that it's thick enough that it's not very messy to work with. It definitely stays put where you put it.
 
#657
My new SH crossover is here and will be going in next week when I bring my cab home from the studio to work on it. Gotta borrow / beg / steel a circular saw by then, but should not be an issue.
 
#658
I'm with Foz on fiberglass insulation. I built my own house, thus I've spent many hours with the stuff. Keep it out of your lungs and off your skin. But surely anyone can manage to line a speaker cabinet without too much self-damage. Just take it slow, measure, cut out each section on the floor with a razor knife, and staple it securely with long staples. It will all be over in 10 minutes and you can breathe a sigh of relief that once more you have defied death. Playing bass in some of the bars I've played in is much riskier than spending a week with the 'glass. Every cabinet I've built has been lined with fiberglass -- simply because it's always around and it works. Wear a mask, long-sleeve shirt, and rubber gloves if you think you need to.
 
#659
particulate fiberglass is awful stuff. no reason these days to use it in projects like this. spent years working for an insulation contractor. i don't see why anyone would push it over poly, plus poly is popular with the ladies:
[Invalid or Expired Link Removed]
 
#660
News flash: Everyone is going to die. If it isn't the garbage truck next weekend, it will be the elevator crashing down in 2041, or maybe even the meteor strike of '32 we'll all recall so fondly later on.

Anyway, why the fear mongering? Take a few less cues from our incompetent mass media and consider the fact that simply walking is more dangerous than some people are making lining a cabinet out to be.
 
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