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GRS 5PF-8 5-1/4" Paper Cone Foam Surround Woofer

Brand:|Model: 5PF-8|Part # 292-405
The GRS 5PF-8 5-1/4" woofers feature a poly-laminate coated cone and a foam surround. They are ideally suited for all sealed-box speaker applications.
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Part # 292-405
  • 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 5PF-8 5-1/4" Paper Cone Foam Surround Woofer

The GRS 5PF-8 5-1/4" woofers feature a poly-laminate coated cone and a foam surround. They are ideally suited for all sealed-box speaker applications. Thanks to their carefully optimized parameters, GRS 5PF-8 5-1/4" 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 Diameter5-1/4"
  • Power Handling (RMS)70 Watts
  • Power Handling (max)130 Watts
  • Impedance8 ohms
  • Frequency Response90 to 8,000 Hz
  • Sensitivity84 dB 1W/1m
  • Voice Coil Diameter1"
Thiele-Small Parameters
  • Resonant Frequency (Fs)100 Hz
  • DC Resistance (Re)7.45 ohms
  • Voice Coil Inductance (Le)0.85 mH
  • Mechanical Q (Qms)4.87
  • Electromagnetic Q (Qes)1.97
  • Total Q (Qts)1.4
  • Compliance Equivalent Volume (Vas)0.11 ft.³
  • Maximum Linear Excursion (Xmax)2.5 mm
Materials of Construction
  • Cone MaterialTreated Paper
  • Surround MaterialFoam
  • Magnet MaterialFerrite
Mounting Information
  • Overall Outside Diameter5.0625"
  • Baffle Cutout Diameter4.75"
  • Depth2.3125"
  • # Mounting Holes4
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
  • Sealed Volume0.08 ft.³
  • Sealed F3107 Hz
  • Vented Volume1.26 ft.³
  • Vented F354 Hz
GRS 5PF-8 5-1/4" Paper Cone Foam Surround Woofer
  • BrandGRS
  • Model5PF-8
  • Part Number292-405
  • UPC844632088452
  • Product CategoryWoofers
  • Unit of MeasureEA
  • Product Rating
    (15 Reviews)
  • Weight1.15 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 5PF-8 5-1/4" Paper Cone Foam Surround Woofer
in the Woofers product category.


GRS 5PF-8 5-1/4" Paper Cone Foam Surround Woofer
GRS 5PF-8 5-1/4" Paper Cone Foam Surround Woofer is rated 4.2 out of 5 by 15.
Rated 5 out of 5 by from GRS 5PF-8This is a frequency Resp. graph I read for this. Please note that this is only for reference because I do not have the best mic in the world but I do feel it is accurate. Hope this is useful.
Date published: 2015-11-19
Rated 3 out of 5 by from Good midrange speakerI purchased these to replace the woofers in my Minimus-77's but I find them impractical for them. They fit like a glove, but sound wrong. I also purchased theHP-5210 5-1/4" Poly Cone Rubber Surround Woofer 8 Ohm speakers, and they were bliss. The latter is a tight fit, but the speakers sound much better than stock!
Date published: 2015-09-26
Rated 5 out of 5 by from Flawless Fit Great Vocals and SurroundReally good for my Advent Mini's to use as surround and sometimes 2.1ch for Vocals when watching TV. Great Price
Date published: 2015-04-26
Rated 5 out of 5 by from Fit like a gloveI bought 2 of these to replace in my Realistic minimus-77 speakers. They fit like a glove. They sound just like they did when they were new. A GREAT value. I will by from Parts Express again.
Date published: 2015-02-24
Rated 4 out of 5 by from Good Value SpeakersI purchased these to replace worn out woofers on a pair of Boston Acoustics speakers that I intended to use for surround sound. The sound is good, however at higher volumes you can start to hear some clipping. Great for surrounds though.
Date published: 2014-12-24
Rated 4 out of 5 by from These do fit the Optimus Pro 77 - but.....I purchased these to replace the beyond-repair woofers in my Optimus Pro 77 speakers after reading another review of another person doing the same. Indeed they do fit nicely, however audibly they are not a good match unless you are just making them simply work again for outdoor or maybe surround use. Why not? The original woofers have a considerable excursion and a deep magnetic gap along with a relatively low resonance for a small woofer. These are the opposite - limited excursion, the gap is narrow (output drops quickly outside of their resting state) and a rather high resonance.Now that makes these a good candidate for a wide-range midrange or a really good replacement for a vintage bookshelf system where the bass rise of around 200Hz is a nice plus - and these have enough higher-end output that a tweeter is not needed for a vintage replacement.But if you are considering these for the classic Optimus Pro 77 and it's similar models, go upward in the product line for the best results. I give these a 4 star rating for what they do well. I'd recommend these for other uses or if you just want to get your old Optimus speakers up and running again on the cheap.
Date published: 2014-12-20
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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 5PF-8 5-1/4" Paper Cone Foam Surround Woofer

I am going to replace all the speakers in my Boston Acoustic T930's. What do you recommend?

Asked by: Big Mikey
Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2015-03-09

What is the diagonal distance, i.e. across the cone, between the mounting holes?

Asked by: Bob J.
Te center to center distance diagonally between screw holes is 5-1/4".
Answered by: MattP
Date published: 2015-12-24

Impedence of woffer tweeter mix

I just ordered 4 of these woofers which are 8 ohms,I also ordered 2 phonolic ring tweeters which are 8 ohms.If i parallel 2 woofers then hook the 8 ohm tweeter on the factory Dayton 2.5 k crossover and set the plug for 4 ohms will that be OK? Any advice on how to connect these ? Or should I order 4 ohm woofers? My amp will drive 4 ohm loads.
Asked by: clod
Let's try to work on those questions... When using a stock crossover - it's best to design to its impedance. Don' worry about your amp. Most amps can handle 4 or 8 ohm loads without issue. When you design a speaker and mix impedances - you're better off custom building your crossover. This is easy to do with a crossover calculator. You plug in the impedance of the drivers, choose the type of crossover (6db/oct etc), the crossover point and it shows you a schematic and the part numbers... To keep it simple - use one woofer, or 4 in series/parallel per side which keeps the same impedance.
Answered by: markajh
Date published: 2012-09-03

If i put a 4 ohm resistor on 2 of these wired in parallel will the load be 4 ohms?

Asked by: BChristy15
If you wire two of these in parallel, the load will be approximately 4 ohms. As a general rule, you should avoid using resistors in woofer circuits.
Answered by: AlonzoTG
Date published: 2014-03-21

replacement of blown speakers

i have 1 infinity sterling video center speaker that both of the 5.5" speakers have blown surrounds and maybe blown voice coils. i am looking for replacements would your p/n 292-405 work in it for replacement speakers?
Asked by: vintron
If the nom. impedance is the same as the original Infinity drivers were, these should work fine with the existing x-over. Final SQ will depend on your opinion, but these should be a good 1st try.
Answered by: C from Claypool
Date published: 2012-03-03


hey i was wondering if i had a 15w amp and used 1 speaker on each channel(2 channels total) would it be bad for the amp
Asked by: 110volts
No, this speaker would be perfectly fine on your 15w amplifier, one speaker per channel.
Answered by: RussR
Date published: 2014-03-21
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