Anyone ever try changing the polyfill?

nspindel

I just ordered up all the materials to re-do the internal wiring of my 4.1's to Cardas Litz, thanks to DarqueKnight for yet another great upgrade. That got me thinking, "What's left to mod????" I haven't done the grill cloth yet, I probably will do at some point, but I was trying to figure out what else besides the drivers, passive radiator, and cabinets is original. The polyfill...

So I had a quick look at PE and they've got this:

http://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-damping-material-5-lb-bag--260-330

Then I made the mistake of reading some of the comments. "Outperforms fiberglass", "Acoustically sublime", "Bass seems cleaner,deeper and more sonically accurate", and most important, "Goes especially well with a 2008 Domaine Louis Michel Chablis Fourchaume Vaulorent".

Hmmmmmm... Anyone ever try it?

TNHNDYMAN

You be the guinea and post your results.

Ha. Ha.

westmassguy

nspindel wrote: »

I just ordered up all the materials to re-do the internal wiring of my 4.1's to Cardas Litz, thanks to DarqueKnight for yet another great upgrade. That got me thinking, "What's left to mod????" I haven't done the grill cloth yet, I probably will do at some point, but I was trying to figure out what else besides the drivers, passive radiator, and cabinets is original. The polyfill...

So I had a quick look at PE and they've got this:

http://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-damping-material-5-lb-bag--260-330

Then I made the mistake of reading some of the comments. "Outperforms fiberglass", "Acoustically sublime", "Bass seems cleaner,deeper and more sonically accurate", and most important, "Goes especially well with a 2008 Domaine Louis Michel Chablis Fourchaume Vaulorent".

Hmmmmmm... Anyone ever try it?

You can get it a lot cheaper. Walmart, Michael's, any craft or fabric store will have it. It's used for stuffing pillows. Same stuff, Polyfil, but not sold or marketed as a high priced audio accessory. They only problem is keeping it in place. With the CRS, you can only do half of the internal cabinet. You don't want it behind the PR. Dacron batting is easy to tack in place, not so with the polyfil.
For Grill Cloth, this is the stuff I use for all my Polk rebuilds: http://www.ebay.com/itm/360286206011?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
Its gorgeous when installed, and as sheer as a Victoria's Secret Negligee. It's as acoustically transparent as anything you'll find.
Other may chime in with their own favorite Grill Cloth.

westmassguy

Here's a photo of my CRS+ with the Grill cloth:

And my 2ATLs

Damned thumbnails still not working right

Toolfan66

Speakerworks has great speaker cloth, it's even on sale, it's the best cloth I have used..

http://www.speakerworks.com/black_speaker_grill_cloth_fabric_p/gcbl.htm

nspindel

Yeah, the thing that's got me procrastinating on the grill cloth is pulling out all the staples, that just has "pain in the arse" written all,over it. Plus, my original grill cloth is in very good shape. And also, I'm afraid that the new cloth would not take kindly to trying to re-inset the Polk badge, which I'm quite fond of.

So... How about that poly fill??

leftwinger57

When I 1st opened up my 2Bs and saw that the polyfil was so white I knew I had very well sealed cabinets. There was no dust no nothing even airborne. The 2 rolls and were laying perfectly until I took them out.I ptretty sure they engineered the volume of the cabinet and got that amount we see now. I'm glad I was cautioned to reroll and replace as seen intitially and not have any in the passive cavity. One thing I keep wondering about is putting polyfill or even Corning Pink into my long gone Infinity SM112s. The rap on those was little lacking on the bottom end ,so playing w/ amounts of fill just might have improved the bass. To late they are long.

westmassguy

nspindel wrote: »

Yeah, the thing that's got me procrastinating on the grill cloth is pulling out all the staples, that just has "pain in the arse" written all,over it. Plus, my original grill cloth is in very good shape. And also, I'm afraid that the new cloth would not take kindly to trying to re-inset the Polk badge, which I'm quite fond of.

So... How about that poly fill??

The CRS grills are small, so pretty easy to work on. There's an upholstery tool called a "Staple Lifter", which makes the job a lot easier. I don't staple the new grill cloth in place, I use 3M #77 spray adhesive on the back side of the grill frame. The only part that is stapled, is the corners after the fabric has been "butterflied" and flattened.
The Polk badges are easy to remove, apply pressure to the pin on the back, and spin the badge like you were unscrewing it, then remove the clip from the hole. Once the new cloth is on, I take the tip of a utility knife, make a small puncture where the hole is, and push the badge pin back in.
Polyfil is just as effective as the original Dacron, but as I said earlier, it's difficult to keep in place.

11tsteve

i re-did the grill covers on my 11T's, and felt the same feet dragging dread going into it, but it was not horrible and the returns were great. My speaks had been in storage for 10 years, and had candle wax on one cover from a party when I was much younger(ick). The new cloth made me feel so much better about everything.
I have a very good pair of needle nose pliers, and I was surprised to find the vast majority of staples pulled quite easily.

geoff727

I have used different fill materials that I've had lying around for several Polk speaker upgrades, always to increase the amount of fill inside the enclosures by supplementing the original rolls. I can report nothing but positive results.

G~

Face

westmassguy wrote: »

You can get it a lot cheaper. Walmart, Michael's, any craft or fabric store will have it. It's used for stuffing pillows. Same stuff, Polyfil, but not sold or marketed as a high priced audio accessory. They only problem is keeping it in place. With the CRS, you can only do half of the internal cabinet. You don't want it behind the PR. Dacron batting is easy to tack in place, not so with the polyfil.

Acousti-stuff and Poly fill are not the same thing. Handling both will make it immediately apparent to you.

westmassguy

Face wrote: »

Acousti-stuff and Poly fill are not the same thing. Handling both will make it immediately apparent to you.

I've used both successfully. Polyfill has finer strands. Fiberglass is supposed to be better than both, but has obvious hazards that go along with it. Dacron batting is easier to work with on a production line, since it's easily quantifiable.

Face

Denim insulation is just as effective as fiberglass and much safer.

nspindel

So I've been thinking more about the polyfill in my 4.1's. You're only meant to have the fill behind the drivers and tweeters, not behind the passive. But that's not much space in a CRS+ cabinet. The passive is on the back of the cabinet and it takes up a good portion of the overall length of the cabinet. The passive is back to back with one of the drivers and the tweeter, so if you can't have material behind the passive then it can't be behind the tweeter and that driver either. So I'm not sure where the stock polyfill should actually be placed. Now if I were to try to change out the material, I wonder what the optimal amount would be. The Parts Express listing says there should optimally be 1/2 pound of fill material per cubic foot of cabinet space. I haven't measured but but I'm guessing a CRS+ cabinet is a max of 3 cubic feet, maybe less. So then 1 to 1.5 pounds of the material per speaker, so the 5 pound bag should be plenty. I've got an inch of Sonic Barrier on each side, so that's even less space.

But I don't know how I'd apply it. To avoid the PR, I'd certainly need to pack it all on one side of the speaker. But then there'd be nothing behind the tweeter and the one driver. Maybe it would be best to just pile it up in the middle of the speaker and let the PR breath as best it can. The stock stuff certainly encroaches on the PR as I've assembled mine, and I never found them lacking bass!

One other challenge is this stuff looks like it's loose, almost like cotton balls. If I'm particular about where this stuff lays in the cabinet, that might be difficult. One idea I'm thinking would be to take a bunch of it and wrap it in grill cloth and make a big pack out of it.

Am I crazy?

westmassguy

nspindel wrote: »

So I've been thinking more about the polyfill in my 4.1's. You're only meant to have the fill behind the drivers and tweeters, not behind the passive. But that's not much space in a CRS+ cabinet. The passive is on the back of the cabinet and it takes up a good portion of the overall length of the cabinet. The passive is back to back with one of the drivers and the tweeter, so if you can't have material behind the passive then it can't be behind the tweeter and that driver either. So I'm not sure where the stock polyfill should actually be placed. Now if I were to try to change out the material, I wonder what the optimal amount would be. The Parts Express listing says there should optimally be 1/2 pound of fill material per cubic foot of cabinet space. I haven't measured but but I'm guessing a CRS+ cabinet is a max of 3 cubic feet, maybe less. So then 1 to 1.5 pounds of the material per speaker, so the 5 pound bag should be plenty. I've got an inch of Sonic Barrier on each side, so that's even less space.

But I don't know how I'd apply it. To avoid the PR, I'd certainly need to pack it all on one side of the speaker. But then there'd be nothing behind the tweeter and the one driver. Maybe it would be best to just pile it up in the middle of the speaker and let the PR breath as best it can. The stock stuff certainly encroaches on the PR as I've assembled mine, and I never found them lacking bass!

One other challenge is this stuff looks like it's loose, almost like cotton balls. If I'm particular about where this stuff lays in the cabinet, that might be difficult. One idea I'm thinking would be to take a bunch of it and wrap it in grill cloth and make a big pack out of it.

Am I crazy?

I've used strips of nylon insect screen to hold polyfill in place

nspindel

Back to this thread again. Still trying to understand what to do with the polyfill in these speakers. I like the idea of using the nylon insect screen to fabricate some sort of bag for the loose material, but then would I be better off having it lay along the bottom of the CRS+ cabinet, or should I try to have it off to the one side leaving the PR completely clear?

westmassguy

I think your head is going to explode if you keep obsessing on this

nspindel

Quite possibly!

F1nut

westmassguy wrote: »

I think your head is going to explode if you keep obsessing on this

I agree.

Phasewolf

If you head explodes over this please feel free to post a pic.

As for the poly-fill I have also thought about playing with the amount in the cabs and taking sweeps with REW to see how things change with each amount. Maybe when I have more time I will give it a try and post up a thread on what I find.

DollarDave

When I did my 4.1TL's, I played with various styles and amounts of poly-fill and what worked best for me was the stuff that comes in rectangles and is about 2 or 2 1/2 inches thick. I can't remember which hobby or fabric store I got it from, but I've seen it during several of my occasional spouse-supporting trips to those money-holes. I had a couple of cuts to make, but is fit the outside surfaces of the cabinet sides perfectly and doesn't come out of place. And, it sounds just right (without the aide of electronic measuring equipment).

nspindel

Well, in an effort to not continue obsessing over this, I finally went ahead and ordered some stuff from Parts Express. I ended up ordering the acoustic fill from there. Given the 1/2 lb. per cubic foot of cabinet space recommendation, 2 lbs. should be plenty for CRS+'s. $20. I'm sure I can get a larger amount for less money from a hobby shop, but leftover polyfill doesn't do me any good. I also ordered a yard of their premium grill cloth. I was considering the other recommendations on this thread, but there were so many rave reviews of the cloth on PE that I decided to give that a go. Also ordered the 3m 77 spray, sounds a lot more desirable than staples. I also ordered a yard of the cheapest grill cloth they had, it was around $7. I'm going to use that to make some sort of container for the polyfill to place inside the speaker.

There. Head safely intact, no explosions!

pitdogg2

nspindel wrote: »

Also ordered the 3m 77 spray, sounds a lot more desirable than staples.

you should still staple. My SDA2a's were not stapled and the glue just started letting loose after some time.

nspindel

You used the same type of glue?

pitdogg2

nspindel wrote: »

You used the same type of glue?

you bet i have gallons of it. In my youth I upholstered. westmassguy is right about that tool you can scream through staples in no time but I do not expect you to go out and buy a tool for one use.

westmassguy

I've been using #77 for years, on my own grills, and for customers. It has never let me down. The only place I put 1/4" staples is at the corners after they've been butterflied, and flattened.

nspindel

Do you apply the glue just to the grill or to the cloth as well?

nspindel

Also, in the unlikely event I ever wanted to change the cloth a second time, how permanent is the glue? Can I get the cloth off after the glue sets?

pitdogg2

westmassguy wrote: »

I've been using #77 for years, on my own grills, and for customers. It has never let me down. The only place I put 1/4" staples is at the corners after they've been butterflied, and flattened.

True but most all glue has a life span. With the particleboard/MDF frame expands/contracts a little with humidity and the corners are where the most stress would be if done right. I agree that there is no need to go like some of Polk did with staples butt to butt. Like you said staple the corners. That is mostly what I meant by "I'd staple also" couple down the side would not hurt. That will make it easier to spray some in there if they ever start to let go.

westmassguy

I think I'll be six feet under before mine let go.
nspindel, I apply two light coats to the back of the grill frames. Always spray the side opposite from you. you don't want the glue on the outside radius edge. I little overspray on the inside edge won't hurt anything. Let the glue "set" for a minute between coats. You then have about 10-15 minute work time. I also recommend painting the front of the frames with Krylon Flat Black before you apply the glue.

nspindel

Ok, will do. Thanks for that.

What about the question of how permanent the glue is. If something happens to the grill cloth down the road and I want to change it a second time, how difficult will it be to remove?