GRS 4PF-8 4" Paper Cone Foam Surround Woofer

Brand:| Model: 4PF-8
Thanks to their carefully optimized parameters, GRS 4PF-8 4" poly-laminated paper cone woofers offer a high degree of compatibility when used as replacement speakers.
  • Perfect for use in sealed-box home theater and music systems
  • Poly-laminated paper cone, treated foam surround, and polymer dust cap
  • Smooth frequency response with minimal cone breakup
Part # 
Weight: 1.4 lbs.  
List Price$7.99
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Your Price
Buy 4-up$4.40
Part # 292-404
Qty:  EA
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Product Details

GRS 4PF-8 4" Paper Cone Foam Surround Woofer

Thanks to their carefully optimized parameters, GRS 4PF-8 4" poly-laminated paper cone woofers offer a high degree of compatibility when used as replacement speakers—they also provide excellent performance in new projects, too.

Product Specifications
  • Nominal Diameter4"
  • Power Handling (RMS)40 Watts
  • Power Handling (max)70 Watts
  • Impedance8 ohms
  • Frequency Response100 to 10,000 Hz
  • Sensitivity84 dB 1W/1m
  • Voice Coil Diameter1"
Thiele-Small Parameters
  • Resonant Frequency (Fs)98 Hz
  • DC Resistance (Re)7.49 ohms
  • Voice Coil Inductance (Le)0.88 mH
  • Mechanical Q (Qms)4.55
  • Electromagnetic Q (Qes)1.9
  • Total Q (Qts)1.34
  • Compliance Equivalent Volume (Vas)0.12 ft.³
  • Maximum Linear Excursion (Xmax)2.5 mm
Materials of Construction
  • Cone MaterialTreated Paper
  • Magnet MaterialFerrite
Mounting Information
  • Overall Outside Diameter4.125"
  • Baffle Cutout Diameter3.75"
  • Depth2.125"
  • # Mounting Holes4
Optimum Cabinet Size *
  • Sealed Volume0.09 ft.³
  • Sealed F3104 Hz
  • Vented Volume1.26 ft.³
  • Vented F353 Hz
  • * Enclosure volume/F3s based on BassBox "optimum" calculations-
GRS 4PF-8 4" Paper Cone Foam Surround Woofer
  • BrandGRS
  • Model4PF-8
  • Part Number292-404
  • UPC844632088445
  • Product CategoryWoofers
  • Unit of MeasureEA
  • Product Rating
    (9 Reviews)
  • Weight1.4 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

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GRS 4PF-8 4" Paper Cone Foam Surround Woofer
GRS 4PF-8 4" Paper Cone Foam Surround Woofer is rated 4.1111 out of 5 by 9.
Rated 4 out of 5 by from Nice little woofer.I strive to to capture every sound on a recording. I want to here the stick hit the drum and the finger sliding on the string. That being said I used this driver in a 5-way speaker as a mid woofer and it worked really well. It seems to work better in a ported cabinet better than a sealed cabinet.
Date published: 2014-04-05
Rated 4 out of 5 by from Trying these in an old BOSE 800 Pro Cabinet as old speakers dieAfter speaking to the great support people at PartsExpress I decided to purchase a number of these drivers as replacements for deteriorating drivers in some ancient Bose 800 pro cabinets I have. Those cabinets use eight 8 ohm 4 inch rectangular drivers. Over the years I have repaired them, but they really need reconing and that is not practical unless I can find the supplies to do it myself. The other alternative is to go with the almost $20 each 1 ohm triangular shaped drivers and replace them all for about $160 a box. At about $4 each, I am giving these a chance.I just replaced a couple of BOSE drivers with these GRS 4PF-8 drivers using foam speaker mounting tape from PE I also purchased to fill in the slight gap that would be left by these slightly smaller drivers. They use the same 4 mounting holes as the original BOSE. While they may not sound quite as good as the originals, or have quite the same volume per watt/sensitiviy or power handling, I think they will suit my purpose as a small club PA or as side fill monitors in larger clubs. I can only do a quick test at home, but they sound OK and are probably "close enough for Rock and Roll."If I had a way easily make my own cabinets, I might make some extras using only the GRS speakers. Now I have a mix of BOSE and GRS...
Date published: 2014-04-05
Rated 3 out of 5 by from it could be betterIts a good little but needs to be dampened of all you will hear is distortion even at LOW volumes
Date published: 2014-04-05
Rated 5 out of 5 by from Worked gretI used these along with some goldwood tweeters to make a music dock for my wife.They sound grey for the price
Date published: 2014-03-30
Rated 5 out of 5 by from My Minimus 7 fixI was able to use these speakers for a fix of several Minimus 7s that I had ordered off of eBay. A few of them came with woofers that were rubbing in the voice coil and sounded pretty bad. I was worried about the match to the tweeter but after hooking them up I stopped worrying. They sounded pretty good from the first time I played music through them. I did a break in and they sound great. I did have to cut off the connectors in the minimus 7s and solder the wire directly to the terminals on the speaker. Had there been a speaker that would have been made by Dayton that fit as well as this one did I probably would have bought it, but I did not see one. I bought these and they have worked out.
Date published: 2014-03-30
Rated 4 out of 5 by from Decent SpeakersI've bought about 50 of these speakers so far. I use them for replacement speakers in some of my Drive-in Movie Speakers.For this they are great.I have had no problems with them what so ever! All my customers seem to like them.They are inexpensive and sound good for what they are.
Date published: 2014-03-09

Product Q&A

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who own this product or have experience with it.
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please email tech@parts-expresss.com  for a prompt reply.
GRS 4PF-8 4" Paper Cone Foam Surround Woofer

Low pass filter needed?

Do I need a low pass filter for these if using them in a line array with Piezo tweeters?
Asked by: LynxTWO
You should use a 1.6 mh coil to filter these, at least that's what I did. Sounds good.
Answered by: Bigblaine
Date published: 2013-04-13

Recommended crossover frequency?

For a 1st order butterworth crossover, paired with the given tweeter, what would a good frequency be/what inductors and capacitors should I get?
Asked by: iamrcubed
The Butterworth slope is not feasible in a 1st order (6db/octave) network. it starts in the 12db/octave,Second order and up.See attached crossover drawing and assuming parts are all 8 ohms...round values to the nearest,,,, good luck
Answered by: salvatore J
Date published: 2012-12-13

Help with calculating ported or sealed enclosure?

I'm attempting to build a cheap... ahem... inexpensive tv soundbar using these woofers. EBP is showing 51.58 which indicates this speaker is good for both ported or sealed enclosures, although it looks like it favors sealed. I've tried online speaker box calculators, but they show at least 6+ cubic feet (EACH - left and right channel) Vb for either designs. That seems just too big for a soundbar.I'm using a 50W x 2 to drive these (and their corresponding PE Buyout tweeter) so I'd like (if feasible) to lean toward a ported design so that I don't have to use all that power for lower volumes. But if a sealed design is the best way to go, well then I go with that. Any suggestions, experiences, or recommendations for a MUCH smaller design would be well appreciated. Thanks in advance!
Asked by: BMan63
Hi Pal,,,lol, funny stuff,, Dual 18" concert subs don't even use 6 cubic ft.Make sure you place those decibel points correctly and type in all numbers exactly!!!0.1 cubic ft. per driver is what i am showing,The internal cabinet volume measurements would be:H 6.00" x W 6.00" x D 6.00",,, 12" x 6" x 6" is 0.25 cubic ft and good for two drivers (with a tad extra space that cant hurt).Cut-off says 39hz, I feel its closer to 50hz !!!!..Be sure to line top back and side with dampening material found here at PE,,,, fiberglass insulation works in a pinch, but you'll itch a bit....Best of luckPS: Keep it sealed, use silicone on all internal seams (leaking air will compromises bass performance)
Answered by: salvatore J
Date published: 2013-01-05

mounting in micro guitar amp

I have a 5 watt @8 ohm peavy amp .I was hoping to upgrade the speaker Do u think this would improve the sound? this speaker looks beefier than the one in the cabinet and better quality..could u send me mounting diagram or give me the dimension for hole center to center for the mounting screws thanks Toml
Asked by: td7849
Hi Tom,,,This driver will work great for the dollar...Overall Outside Diameter is 4.125"Baffle Cutout Diameter is 3.75"Depth 2.125"screw positioning would be circle squared but I'd wait for driver before drilling...If i can suggest spending a little more for best output and better match with your Peavy's 5 watt amp,recommend theVisaton 9020 W100S 4" Woofer with Treated Paper Cone 4 Ohm.The advantages are:2db louder/ more efficient @ 86 db with 1 watt of power.its 4 ohm impedance will automatically allow the Peavy amp to double its power by producing 10 watts...Calculating and doing the math using both speakers parameter sensitivity @ 3.3 feet:the Visaton and 10 watts, SPL will be 98.9 db whereas the GRS 4PF-8 93.9 db.The difference in 5 may not seem like much, butt, with audio 5-6 db is like Niagara Falls to a garden hose.....if you can, go with the Visaton.Overall Outside Diameter 4.80"Baffle Cutout Diameter 3.70"Depth 1.89"My Best... S
Answered by: salvatore J
Date published: 2013-01-16

I recently used these in a school project are there any replacements that have more bass? or go lower in frequency?

Asked by: JC123
This depends on how low these are playing. With a 4" driver you can't expect much below 70-80 Hz in a small cabinet. We do offer a few 4" models that will play into the upper 50's in a larger enclosure but they are in the $25-$30 price range.
Answered by: MattP
Date published: 2013-01-26

recommended cabinet size

what size cabinet should be used to place two of these in plus a Dayton Audio DC28F-8 1-1/8" Silk Dome Tweeter? I'm build a cheap custom center channel speaker.P.S. I would prefer a sealed box but a ported box is okay.
Asked by: Jarad
A sealed enclosure of approximately 0.25ft³ will yield an F3 frequency of almost exactly 100Hz, which should be quite conducive to your center channel enjoyment.
Answered by: RussR
Date published: 2011-05-24

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