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

Brand:|Model: 4PF-8|Part # 292-404
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.
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Part # 292-404
  • 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

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 (determined using BassBox 6 Pro High Fidelity suggestion)
  • Sealed Volume0.09 ft.³
  • Sealed F3104 Hz
  • Vented Volume1.26 ft.³
  • Vented F353 Hz
GRS 4PF-8 4" Paper Cone Foam Surround Woofer
  • BrandGRS
  • Model4PF-8
  • Part Number292-404
  • UPC844632088445
  • Product CategoryWoofers
  • Unit of MeasureEA
  • Product Rating
    (17 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.

View similar products to the GRS 4PF-8 4" Paper Cone Foam Surround Woofer
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GRS 4PF-8 4" Paper Cone Foam Surround Woofer
GRS 4PF-8 4" Paper Cone Foam Surround Woofer is rated 4.1176 out of 5 by 17.
Rated 5 out of 5 by from Fantasticput these in an old boom box and these worked out great. sounds way better than before.
Date published: 2015-05-02
Rated 4 out of 5 by from Great Value SpeakerDon't confuse this with a top-level hifi driver, it would get 1 star if that's what it were meant to be. But for around $6 it's a good speaker. It has decent sound quality so it earns a solid 4 stars. The small frame makes it easy to use in replacement situations with limited real estate.
Date published: 2015-03-03
Rated 4 out of 5 by from replacement woofersthese woofers work and sound great used them as replacements in a pair of teac bookshelf speakers they are ported and i added some accoustic foam to dampen the bass a little bit n seems to do the trick good bass for little speakers tho
Date published: 2015-01-05
Rated 1 out of 5 by from size does match advertised spec.Cutout size for this speaker is 3 3/4" and not the specified 4" in ad.
Date published: 2014-09-30
Rated 5 out of 5 by from Good option for Optimus 50 midrange replacementMy old Optimum-50 midrange speakers blew, well not blew, deteriorated, so I searched for replacements. These seemed to fit the bill - not exact spec replacements, but close enough. They almost fit in the cabinets, but with a little Dremel tool work I was able to bevel the opening and bezel for a nice fit. They sound good to me, and that's all that matters.
Date published: 2014-09-26
Rated 5 out of 5 by from Great soundsi bought these for the A-pillars in my car, i have 3 per pillar and they are loud and clear off my head unit. i havent amped them yet but off the head unit they get a little too low so they dont distort but they arent as sharp on certain rap songs but for 4.40 a piece, they sound amazing and i love them. will most likely buy more
Date published: 2014-09-03
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Product Q&A

Get your questions answered from other customers
who own this product or have experience with it.
If your question requires design or troubleshooting information,
please email  for a prompt reply.
GRS 4PF-8 4" Paper Cone Foam Surround Woofer

Going to build a Bluetooth boom box with these and some GRS tweeters.  What size box and port should I build for decent bass?  Or should I run a sealed cabinet.  Plan is to build it out of 1/2" baltic birch plywood.

Asked by: SpinnerRow
A sealed .09 cubic foot box will provide the flattest response but will roll off a little earlier. You can go up to a .25 cubic foot vented cabinet and and tune it to 80 Hz, that will provide a peak at around 100 hz which will make the bass presence a little more apparent though. That would require a 1.5 inch diameter by 1.5 inch long port
Answered by: Chrisf
Date published: 2016-02-04

3 3/4 cutout are these going to sit flat on the baffle? or the going to sit up a little? and are they supposed to sit up?

Asked by: hook
With a 3-3/4" cutout the frame will sit slightly proud of the baffle but it will just less than 1/8".
Answered by: MattP
Date published: 2014-12-11

Good Day, My question is how would a pair of GRS 4PF-8 4" with a 1/2 Mylar dome tweeter speaker work well for a in wall center channel speaker?

Asked by: Coair
This should work well as long as there is a crossover involved. This will depend on the safe crossover point for the tweeter you plan on using.
Answered by: MattP
Date published: 2014-11-28

I'm going to use four of these four a 8 ohm load series/parallel. And i'm going to use a piezo tweeter can i use in-line resistor for the tweeter.and let the woofer run full range. Im just asking of a simply way and cheapest way of a crossover. "Thanks"

Asked by: hook
For your application, it should be sufficient to just use a resistor on the piezo element and let these drivers run full range. However, keep in mind that the capacitance of the piezo element works with the resistor to define an RC high-pass filter, so the actual high-pass frequency of the tweeter will also change with different resistor values. I would start with a 10 ohm and a 20 ohm resistor, then use an L-pad before the tweeter and filter resistor to set the appropriate tweeter level.
Answered by: DaytonAudio_Rory
Date published: 2014-11-20

Hello! The cutout diameter says 3.75 on the baffle . Can i get buy on a cutout 3 5/8 diameter on this woofer?

Asked by: hook
Unfortunately no, the smallest cutout this woofer will fit in is 3-3/4".
Answered by: MattP
Date published: 2014-11-19

I'm looking to build a dodec speaker (omnidirectional 12 drivers).  Would this speaker be a better choice than the GRS 4AS-4?  

Asked by: GConk
Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2014-10-22
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