Is there a way to measure polyfill accurately?

VR3VR3 Posts: 21,848
edited November 2005 in DIY, Mods & Tweaks
I was wanting to use Polyfill (just for giggles) instead of the fiber glass inside my speakers currently - and I was wondering what was the best and most effective way to go about measureing it...

Thanks...
Vr3Mods.com ///// Version3Audio.com

"No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
Post edited by VR3 on
«1

Comments

  • JstasJstas Posts: 13,546
    edited November 2005
    Double posting it tonight, huh?


    Anyhoo, grab a rubbermaid bin or something and weight it on a scale. Write down that weight. Now add the amount of polyfil you want to use. Write down that weight. Subtract the weight of the bin from the total weight of bin + polyfil. That's how much polyfil you have.
    You're just jealous 'cause the voices don't talk to you!
  • VR3VR3 Posts: 21,848
    edited November 2005
    Dangit! My connection is screwy lately... so slow and booting me like crazy!

    Thanks - would a regular scale work fine (kind you weigh yourself) - I'm figuring this is under 1 pound...

    Thanks... sorry for the double post
    Vr3Mods.com ///// Version3Audio.com

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • audioblissaudiobliss Posts: 12,633
    edited November 2005
    Yeah...just reach in grab a handful...that should work fine.

    This post inspired by Sid's equally irrelevant posts in my 'Physics Question' thread.

    :rolleyes: :p :D
    Jstas wrote: »
    Simple question. If you had a cool million bucks, what would you do with it?

    Wonder WTF happened to the rest of my money.

    In Use
    PS3, Yamaha CDR-HD1300, Parasound P/HP-850, Parasound HCA-1000A, Klipsch RF-35
    In Storage
    [Home Audio]
    Rotel RCD-02, Yamaha KX-W900U, Sony ST-S500ES, Denon DP-7F, ASL Wave 20 monoblocks, Pro-Ject Phono Box MKII

    [Car Audio]
    Pioneer Premier DEH-P860MP, Memphis 16-MCA3004, Boston Acoustic RC520
  • JstasJstas Posts: 13,546
    edited November 2005
    Dunno. Most bathroom scales aren't that accurate I would think. You could try it. I can't promise results though.

    Don't they sell polyfil in bags that are listed in volume but have weight listed also? Like 2 liters of polyfil (38 grams) or some silly stuff like that?

    BTW, easy place to find conversion tools and calculators: http://www.math.com
    You're just jealous 'cause the voices don't talk to you!
  • JstasJstas Posts: 13,546
    edited November 2005
    Oh yeah. Don't go and get raped by the audio stores selling polyfil. It's the same stuff as what you can get in the arts/crafts and fabric stores for 1/5th what an audio/video store will sell it for.

    All polyfil is is spun polyester. Sometimes nylon but usually polyester.
    You're just jealous 'cause the voices don't talk to you!
  • pitdogg2pitdogg2 Posts: 8,301
    Reported Aniced1984
  • mhardy6647mhardy6647 Posts: 15,617
    Personally (and FWIW, knowing no one's looking for my 2 cents!) I think stuffing loudspeakers is like seasoning in cooking.
    Stuff to taste (i.e., stuff, listen, stuff - or de-stuff, listen again, repeat as needed).
    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

  • pitdogg2pitdogg2 Posts: 8,301
    edited December 2017
    I might tend to agree Doc if I was more smarter. :D I have noticed that some speakers are stuffed to the gills, while others are just a smidgen or two. My SDA1 signatures are stuffed. The roll is very tight and leaves a impression from the back of the speaker magnets. Now since I am not the first owner who's to say that someone along the line of owners didn't put more in ? It is one long sheet rolled up and sits tightly in the chambers. On the other hand I have seen SDA2.3TL's that have a small 1.5" dacron sheet rolled up that barely will stay up behind the midwoofers. If you owned a set like that would you put more in to the point like my own speakers, stuffed in tightly to impress upon the magnets?
    Post edited by pitdogg2 on
  • JstasJstas Posts: 13,546
    It kinda doesn't work that way. Most people don't really understand how/why it works correctly but I don't really want to get into explaining it right now.
    You're just jealous 'cause the voices don't talk to you!
  • EndersShadowEndersShadow Posts: 15,064
    Jstas wrote: »
    Oh yeah. Don't go and get raped by the audio stores selling polyfil. It's the same stuff as what you can get in the arts/crafts and fabric stores for 1/5th what an audio/video store will sell it for.

    All polyfil is is spun polyester. Sometimes nylon but usually polyester.

    Buy cheap walmart 5$ pillows and tear em up and use that.... even cheaper hehehe.....
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
  • pitdogg2pitdogg2 Posts: 8,301
    Jstas wrote: »
    It kinda doesn't work that way. Most people don't really understand how/why it works correctly but I don't really want to get into explaining it right now.

    well stop back when you have time inquiring minds would like to have you spill knowledge. Yes my good friend owns a upholstery business I get mine from him it is EVEN cheaper than the craft stores. who in my area charge 5.00 a foot and it is not as thick as the 1.5" that Polk used. All the craft stores in my area only stock 1/2" dacron.
  • Moose68BashMoose68Bash Posts: 3,485
    mhardy6647 wrote: »
    Personally (and FWIW, knowing no one's looking for my 2 cents!) I think stuffing loudspeakers is like seasoning in cooking.
    Stuff to taste (i.e., stuff, listen, stuff - or de-stuff, listen again, repeat as needed).

    I agree with @mhardy6647.

    However, when I used Acousta-Stuff in my SDA SRS 1.2tl speakers, I purchased a 5# bag from Parts Express.

    In the product information about Acousta-Stuf, the following advice is given about the amount to use:

    "Most sealed and vented enclosures require 1/2 lb. of damping material per cubic foot of enclosure. For best results it is recommended to loosely fill the material throughout the enclosure."

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

    Of course, in "stuffing" speakers with a passive radiator, you don't want to put any fill behind the radiator.
    Family Room, PS Audio PW Transport, DirectStream DAC; AQ Sky XLRs, Perreaux SM6 MKII Pre; AQ Sky XLRs, Perreaux Prisma 750 Amps or CAT 600.2 Dualmono Amp, Morrow SP7 Speaker Cables, SDA SRS 1.2tls (RD0198s, Dreadnought, Black Hole 5, Acousta-Stuf, Dynamat Extreme, JBWeld. Vr3 Mods: "The Abbot" Monastery-Level Xovers, Custom Internal Wiring, Binding Post Plates, & SDA ICs).

    Exercise Room, Wadia 171 iPod Dock, PS Audio PerfectWave MkII DAC, AQ Sky XLRs, Perreaux SM6 Preamp, AQ King Cobra RCAs, Perreaux PMF3150 Amp, Dreadnought, Supra Rondo 4x2.5 Speaker Cables, SDA 1Cs (Vr3 Mods Xovers).

    Synology 713+ NAS on Gigabit LAN serving PW MkII DAC & DirectStream DAC.
  • pitdogg2pitdogg2 Posts: 8,301
    I would think the loose stuff would be even more susceptible to falling down behind the passive.
  • mhardy6647mhardy6647 Posts: 15,617
    edited December 2017
    Even though, in principle, stuffing an enclosure (which, in essence, makes the enclosure feel bigger to a speaker driver by dissipating the back wave energy as heat) is straightforward, in practice it's largely art and - sort of like wires and other cults of the arcane in this hobby - there are adherents to all sorts of idiosyncratic belief systems related to appropriate materials, volumes, and placement.

    For example, transmission lines (and some other, similar enclosure morphologies) are said by some folks to absolutely require long-fiber wool for best results.

    Mind you, I'm not (for a change!) making a judgment; just seemed like something worth adding to this thread :|


    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

  • ken brydsonken brydson Posts: 6,625
    Youz guys do realize this is a 12 year old thread dredged up with a spam post, right?
    HT/Main- Panny 50" G10 Plasma, Pioneer SC-1222k AVR, Panny DMP-BD60 BDP, Polk LS90 mains, CS350LS center, LS/fx side surrounds, LS50 surround backs, SVS 25-31PC+ sub, Harmony One

    Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t
  • mhardy6647mhardy6647 Posts: 15,617
    well -- now -- yeah. :/

    but, you've gotta admit, it's an interesting topic.

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

  • pitdogg2pitdogg2 Posts: 8,301
    Youz guys do realize this is a 12 year old thread dredged up with a spam post, right?

    Yea whatcha point ;)

    I just figured why it's here why not B)
  • ptrooperptrooper Posts: 211
    His comment is gone,,,your reporting must have scared him off lol
    pitdogg2 wrote: »
    Reported Aniced1984

  • pitdogg2pitdogg2 Posts: 8,301
    Mods remove them.
  • pkquatpkquat Posts: 525
    Jstas wrote: »
    It kinda doesn't work that way. Most people don't really understand how/why it works correctly but I don't really want to get into explaining it right now.
    pitdogg2 wrote: »
    well stop back when you have time inquiring minds would like to have you spill knowledge.

    I'm curious too. My experience has been the rolls did a little bit of dampening as well for MW's and tweeters. Although rolls / sheets seamed more tightly packed their rolled form performed similar to the fluffy stuff for cabinet volume and effect on bass.

    A 2cents find as well. Doubling the polyfill in 5jr+'s, 1 roll behind the tweeter and 1 behind the MW, helped the bass and IMO gave a fuller sound.
  • JstasJstas Posts: 13,546
    OK, so first, a couple things about polyfill.

    - It's sold by weight so if you buy a 10 pound box/bag of it, it's 10 pounds of spun polyester.
    - There is another weight rating for it and it has to do with how thick the strands are, like speaker wire has a gauge. Typically, you want a lighter weight because you can get a higher density which is important.
    - You only really see the higher weights in batting because it's used as insulation, stuffing for stuff like padded quilts and seat cushions. The loose stuff in bags is typically for stuffing toys, pillows, etc.
    - You can buy it in loose bundles or rolled batting. Either way, it will do the same thing in a speaker enclosure.

    Stuffing a speaker box, should you?

    Quick answer: you can but you probably shouldn't. It's honestly a band-aid in most cases.

    Long answer:

    Look, I don't care what your "ears tell you", stuffing a speaker that didn't have polyfill in it prior to your bright idea is going to hurt performance. Now, with that out of the way, here's why.

    First, how polyfill works.

    Polyester is a very smooth, reflective surface. So is the alternate, spun nylon. Nylon is also more rigid and you don't see it as much in speakers because it's more apt to damage motor structures. But because of that smoothness, it's very reflective. Reflective is also deflective. It does two things, a physical difference and an audible difference.

    The physical is the most important. A speaker enclosure is essentially an air spring. It creates a vacuum when the driver moves out of the basket and it creates a high pressure pocket when the driver moves into the basket. The vacuum keeps the driver from over-excursion damage, the pressure pocket keeps the driver from being able to bottom out. When you stuff a speaker with polyfill, it essentially slows down the air movement in the enclosure because it is diffuse. The multiple fibers in random arrangement will make the air bounce off them and in all directions. This slows the air movement down and creates turbulence. So every time the driver moves in or out, the air movement is slowed by the polyfill. The effect this creates is that it makes the enclosure behave like a larger enclosure. We'll get to what that does in a minute. It makes it behave like a large enclosure by slowing the air movement. Slow the air, you slow the backwave as well. It takes longer to reach the walls of the enclosure. When it does that, it can actually reduce how fast the pressure or vacuum is built up in the enclosure. That can affect how far your driver extends and whether it bottoms out or not. Not a big deal, right? Well, no, it is.

    If your VC is designed to stay in a certain spot in the motor structure, it can extend past that sweet spot from the over excursion in either direction. At high volume levels, there is a possibility that you can send the VC out, past the ends of the pole piece in the motor structure. That can cause the driver to actually overheat because if the VC goes past the magnetic field then you effectively reduce the VC's size for the magnet to act on so you can momentarily decrease the resistance while increasing the load on the part of the VC that is still in the magnetic field. You're doing it at the driver's peak as well. Because of that, the driver is not operating at it's highest control potential and you are relying more on the surround and spider to control the movement. That taxes those parts more than normal and can wear them out sooner. If they wear out and lose their control capability, you can actually blow the driver because the VC being extended past the pole piece can either impact the pole piece and seize or it can tear the cone/spider/tinsel leads.

    Also, when you stuff a speaker, you move and vibrate the fibers of the polyfill with the driver movement. When that happens, they can eventually fatigue and if the fill is too close to the driver, the motor structure venting can clog up and cause overheating. It can also cause physical failure by making small holes in the control structures that can be stretched out and expanded under even just normal use. Yes, I am not making this up. But, over-stuffing can also slow air movement enough that even a venting system on the driver that isn't clogged isn't moving enough heat out of the motor structure to be efficient. It's more pronounced in, say, a subwoofer where the forces are much larger than what you would find in a full-range speaker. However, overdrive your full range speakers and stuffing a speaker can become an issue.

    Now, the sound stuff. We already know what polyfill does physically to the enclosure. So that artificial expansion of the enclosure space will do a few things. We'll go over the positive later. The negative is that it can dampen response and cause the resonance of the enclosure to change. The problem with that is it can cause things to rattle that previously did not rattle. It can also cause the driver to hit it's resonance points and kill efficiency which can cause audible distortion. That's typically found in a sealed enclosure.

    In ported enclosures, it can reduce port flow velocity which can hamper low-end frequency response by changing the port tuning. Typically, you want the port to be tuned to compliment the driver at it's peak efficiency point. That requires length and width calculations. It can also cause port noise or even cause the driver to suck the air column in the port back into the port because the air spring behind the driver is weaker. That makes noises like blowing across a bottle neck. I've actually heard these noises.
    You're just jealous 'cause the voices don't talk to you!
  • Viking64Viking64 Posts: 1,064
    faag9ub35dmk.jpg
  • txcoastal1txcoastal1 Posts: 8,648
    ^^^ Let me assume that you're one of those pet owners that resembles their animals :p :D :D :D
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures, Simaudio 780D DAC
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Modwright LS100, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers
  • Viking64Viking64 Posts: 1,064
    Close. :p

    rcsuys2lyaek.jpg
  • pitdogg2pitdogg2 Posts: 8,301
    edited December 2017
    Great stuff John. Some I did know but all in all more knowledge is never a bad thing.

    Thanks
  • Viking64Viking64 Posts: 1,064
    pitdogg2 wrote: »
    Great stuff
    Thanks
    Great STUFF???

    w7qn13314c34.jpg
  • machonemachone Posts: 856
    How can you type that much!!!!
    Mojo Audio Joule v5>>Quantum Byte w/JRiver 21 and Fidelizer>> Starlight 7 USB >> Marantz SA 8005>> Equinox 7>>
    Hafler DH-110 Preamp + (Musical Concepts LXII Elite Mod) >>Equinox 7>>
    Hafler DH-500 Amp+ (Musical Concepts PA-6 Elite Mod) >>Belden 5000 10 ga cables>>
    SRS 2.3TL (Fully Modified)...SDA-1A (Fully Modified with Dimensional Tweeter Delete)
    1KVA Dreadnought
    Pioneer PLX-1000 Turntable - Shure SC35C/N35X - V15III/VN35HE
    Yamaha TX-540 Tuner...Sony BDP-S570

    Separate subpanel with four dedicated 20 amp circuits.
    1. Amplification 2. Analog 3. Digital 4. Video

    "All THAT IS LOST FROM THE SOURCE IS LOST FOREVER"
  • JstasJstas Posts: 13,546
    machone wrote: »
    How can you type that much!!!!

    This is completely uncalled for and why I don't post much anymore. I go through all this effort to help some people out because I can. Then I get mocked and dumped on because I took some time out of a lunch break to provide an answer with complete thoughts formed with proper grammar, spelling and punctuation. All because it's beyond your comprehension that someone can form a complete answer and explain complex concepts with a keyboard.

    You're just jealous 'cause the voices don't talk to you!
  • pitdogg2pitdogg2 Posts: 8,301
    edited December 2017
    machone wrote: »
    How can you type that much!!!!

    John is an IT pro, putting simple words together is a cake walk. In his day in day out job he strings together lines and lines of gibberish that we all depend on these days on planet earth.
«1
Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!