Dayton Audio ST305-8 12" Series II Woofer

Brand:| Model: ST305-8
The new generation of Dayton Audio Heavy Duty woofers features natural sounding paper cones that are chemically treated for extra durability and long life. The ST305-8 12" Series II woofer is suitable for pro or home audio subwoofer use.
  • Natural sounding paper cones that are chemically treated for extra durability and long life
  • Consists of a rubber surround and large flat spider for superior damping
  • Feature a large magnet structure
  • Made in USA
Part # 
Weight: 15.33 lbs.  
List Price$129.99
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Your Price
Buy 4-up$90.06
Part # 295-120
Qty:  EA
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Product Details

Dayton Audio ST305-8 12" Series II Woofer

The Dayton Audio ST305-8 Series II heavy duty 12" woofers feature a large magnet structure, vented pole piece, bumped backplate, and large voice coil. This combination provides excellent power handling capability, high efficiency, and very low distortion. The ST305-8 speaker's suspension system consists of a rubber surround and large flat spider for superior damping characteristics and outstanding transient response. Made in the USA.

Product Specifications
  • Nominal Diameter12"
  • Power Handling (RMS)275 Watts
  • Power Handling (max)550 Watts
  • Impedance8 ohms
  • Frequency Response25 to 2,000 Hz
  • Sensitivity92 dB 1W/1m
  • Voice Coil Diameter2.5"
  • Magnet Weight56 oz.
Thiele-Small Parameters
  • Resonant Frequency (Fs)29.6 Hz
  • DC Resistance (Re)6 ohms
  • Voice Coil Inductance (Le)3.07 mH
  • Mechanical Q (Qms)10.55
  • Electromagnetic Q (Qes)0.36
  • Total Q (Qts)0.35
  • Compliance Equivalent Volume (Vas)4.52 ft.³
  • Mechanical Compliance of Suspension (Cms)0.36 mm/N
  • BL Product (BL)15.92 Tm
  • Diaphragm Mass Inc. Airload (Mms)81.33g
  • Maximum Linear Excursion (Xmax)8 mm
  • Surface Area of Cone (Sd)506.7 cm²
Materials of Construction
  • Cone MaterialCoated Paper
  • Surround MaterialRubber
  • Voice Coil Wire MaterialCopper
  • Voice Coil FormerKapton® / Polyimide
  • Basket / Frame MaterialSteel
  • Magnet MaterialFerrite
Mounting Information
  • Overall Outside Diameter12.03"
  • Baffle Cutout Diameter10.95"
  • Depth6.25"
  • Bolt Circle Diameter11.59"
  • # Mounting Holes8
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
  • Sealed Volume1 ft.³
  • Sealed F368 Hz
  • Vented Volume2.52 ft.³
  • Vented F341 Hz
Dayton Audio ST305-8 12" Series II Woofer
  • BrandDayton Audio
  • ModelST305-8
  • Part Number295-120
  • UPC844632000041
  • Product CategoryWoofers
  • Unit of MeasureEA
  • Product Rating
    (41 Reviews)
  • Weight15.33 lbs.
  • California Prop 65

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

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Dayton Audio ST305-8 12" Series II Woofer
Dayton Audio ST305-8 12" Series II Woofer is rated 4.3902 out of 5 by 41.
Rated 5 out of 5 by from Great sounding speakerPlays awesome, would recommend this to my friends, great to play outdoors on my deck.
Date published: 2014-07-01
Rated 4 out of 5 by from Decent woofer for the money.I bought these woofers to replace the ones in my home built 3-way speakers built in the 90s. One of the original Nippon 12" woofers was bad (voice coil scuffing). So I used these Dayton ST305-8 as replacements. They have plenty of bass and handle plenty of power as I am powering them with my vintage Adcom GFA-1amplifier. They do have a slightly different response than my old Nippons (a little peaky) but overall I am satisfied.
Date published: 2014-05-08
Rated 5 out of 5 by from So Helpful!When a woofer in my very expensive Genelec 1037a speakers failed because the form surrounding it didn't like the humidity here in Hawaii I wasn't sure where to turn. The Genelec factory had no replacement parts and no suggestions. Parts Express discussed the specs with me and these woofers have done a terrific job getting my Gelelec's back into my recording studio. Thanks!
Date published: 2014-04-09
Rated 5 out of 5 by from JBL 126A replacementI stumbled across a set of JBL Jubal L65 speakers a couple weeks ago. Unfortunately the original woofers were replaced with pyle 12" woofers. I started the search for replacements without much luck and the only source was that auction site. The pricing too for original drivers was crazy. i ended up calling PE for a recommendation and ended up with a pair of the series 2 woofers. They were a drop in and after hooking them up was really surprised at how well they fit with the driver arrangement.No complaints as of yet and the original woofer was crossed at 1000hz. well bult and made in america to boot! They are not yet fully broken in and given some more listening time should sound even better.
Date published: 2014-04-01
Rated 5 out of 5 by from Great Woofer for the money!!Bought two of these to replace a couple of dry rotted woofers I had in a set of 30 year old speakers that I bought with a stereo stand system. Was not expected too much from these floor cabinets even after the replacement; they were not $500 speakers in the first place. But WOW, these new woofers made the speakers sound like a million bucks!! Very pleased. Nice deep bass and evenly matched. Good value for the price.
Date published: 2014-01-30
Rated 5 out of 5 by from Converted Fender Twin Reverb to Hi-fiUsed this speaker along with a horn, driver and crossover to convert an Fender Twin guitar amp to use it for keyboards and acoustic guitar. ++++++ worked beautifully.
Date published: 2014-01-25

Product Q&A

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who own this product or have experience with it.
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Dayton Audio ST305-8 12" Series II Woofer

With 70 watts of power, would these speakers have advantages over the DC300-8? They will go into ported 1.5cu ft cabinets. Also can I extend the 2.5in dia port tube with an elbow and extend up inside or reduce port diameter to tune the cabinet lower?  

Asked by: Mike50
With only 70 watts there will be no real difference between these drivers in terms or tuning and output. The Series II will work a bit better in the smaller volume, but the audible difference would be negligible.
Answered by: MattP
Date published: 2014-10-20

I need new woofers for my Sansui sp-2500 speakers (1.53 cu ft). The originals say 6ohm 25watt, and have an spl of 98db. My Sansui 7000 @ 70 watts rms per channel will be running these. Is this speaker a good replacement; other cheaper good candidates?

Asked by: Mike50
This woofer will work well, the sensitivity of the Sansui speakers is pretty optimistic. The less expensive Dayton Classic DC300 will also work well.http://www.parts-express.com/dayton-audio-dc300-8-12-classic-woofer--295-320
Answered by: MattP
Date published: 2014-10-17

I changed my mind and want to put THESE 12s in my 1.65 cu. ft. box. What are the optimal port dimensions for this application?

Asked by: denzee300
I would recommend a 4" diameter, 10" long port for a tuning frequency of 40 Hz.
Answered by: MattP
Date published: 2014-03-17

I need some help in replacing a blown woofer. I have Infinity SM122. Can you recommend a pair of woofers to replace my blown one. I would probably buy a pair and take out my good one so the pair match up.

Asked by: 8pepsi8
Our best selling woofer for those speakers will be the Dayton DC300-8 which you can see below.http://www.parts-express.com/dayton-audio-dc300-8-12-classic-woofer--295-320
Answered by: MattP
Date published: 2014-03-15

Could you look up the specs to the old version of this woofer?

I bought these many years ago, same part number, but the box lists different specs, but only a few. Mine has a 67 oz magnet, 93.4 db sensitivity, 29-3000 response, Fs:29 Qts: .34 Vas:7.62 cuft I want to use them for an econowave project, but it seems like they won't go low enough
Asked by: Dutchy
I cannot find anything older than 1997 when these woofers were new. Unfortunately the specs then are the same as they are now. Are you sure it was this model?
Answered by: MattP
Date published: 2012-10-17

Enclosure for F3 ~30Hz

....or what is the most optimized enclosure size, type, vent length etc. for music?
Asked by: chris45
I would go for a 2.5 to 3 cuft ported with two 3" ports 15" long. This puts your F3 at 40hz, but 30hz is only down 2-3 dB from 40hz. With room gain it should flaten out the response so you should end up with good authority to the mid 20's.
Answered by: mtg90
Date published: 2013-04-04

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