Subwoofer Review - Rockford Fosgate T212D4
June 4, 2005
By Paul Sonoda
Bigger is better. That’s what the guys at Rockford Fosgate think. New Power Series amplifiers from Rockford can deliver upwards of 3000 watts. All they needed now was woofers that can handle that kind of power and turn it into bass. Their answer is the T212D4. With a big MSRP of $699, the Rockford Fosgate T212D4 definitely says bigger is better.
First Look
The Rockford Fosgate T212D4 is a dual 4-ohm, high-excursion 12 inch woofer. The woofer is also available in a dual 2 ohm version. Did I say this woofer is huge? With a cut out diameter of 10-13/16 inches, the T212D4 is nearly 9 inches deep. Add the height of the cool metal trim ring and you have a woofer that appears square. Terminal connections, provided via slot loaded spring terminals, can accept up to 8 gauge speaker wire. The cast aluminum speaker basket is a unique two-part construction where the motor structure resides on an inner basket with the arms of the outer basket extending up from the base of the woofer to hope the surround and woofer cone. To top off the Rockford Fosgate T212D4 is a Machined looking aluminum concealing ring the hides some of the woofer mounting screws and give the T212D4 a menacing purposeful look.
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topCloser Look
The Rockford Fosgate T212D4 is all about power handling. The large four inch voice coil former is made from anodized aluminum that offer superior head dissipation over other types of voice coil materials. The voice coil wire is flat edge-wound aluminum to maximize the amount of the voice coil in the magnetic gap and hence the power capability. To provide the motor strength, the T212D4 uses a 292 ounce (that’s 18.25 pounds!) triple stacked magnet motor design. This motor structure not only provides an impressive Force Factor (BL) but also provides the clearance for the huge excursion capability of the woofer. Long voice coil generates a X-Max (Linear one-way excursion capability where the voice coil is still completely inside the motor gap) of 1.5 inches. Actual mechanical excursion is much higher.
To control the massive excursion Rockford uses a high excursion Thermo-Rubber Surround. The surround’s shape is taller that it is wide. Like several other woofers using this design, the surround maximizes cone area while still allowing for high excursion travel. The T212D4 uses a “Mirror Image Symmetrical Spiders’ mounted to a spider support ring. The identical spiders are arranged in a mirrored configuration which maintains linear suspension travel and delivers superior mechanical stability under high excursion. The peak mechanical excursion is said to be nearly 3 inches! The spider support ring also allows for the extremely large 12 gauge tinsel leads to connect between the speaker terminals and the voice coil. This all adds up to a woofer capable of handling 1000 watts of continuous power with 2000 watts as its maximum short term power handling.
Manuals/Web Support
The Rockford T212D4 owner’s manual provided information on the complete line of Power Series woofers. Included in the manual is relevant woofer parameters and recommend enclosures. For the T212D4, only vented enclosures are recommended. The Rockford Fosgate website, www.rockfordfosgate.com, was easy to navigate and I was quickly able to find information on the T212D4 woofer. There was marketing information about the features of the woofer as well as the owner’s manual and spec page available for PDF download. The enclosure supplied to me for testing was built using referencing a “Power Subwoofer Page”. This enclosure recommendation is provided to your local authorized Rockford Fosgate dealer. I was not able to locate this enclosure page on the website. According to Rockford, these enclosures are more difficult to construct and are provided to the dealer. Based in this information, getting the enclosure build at an authorized Rockford Fosgate dealer will most likely yield superior results.
Installation
The enclosure provided is a slot-loaded vented enclosure measuring 2.25 net cubic feet. The exterior dimensions are 15.25 x 15.25 x 30 inches which occupies more than 4 cubic feet of cabin space. This enclosure is marginally larger than the enclosure recommended in the owner’s manual the main difference is the port area which is roughly double of the enclosure in the owner’s manual. (More port area usually generates higher enclosure efficiency) The tuning frequency is still set to 40Hz. Overall this enclosure/woofer combination weighs more than 100 pounds.
Sound Q & Performance
It doesn’t take a rocket surgeon (or was that brain scientist?) to know that this woofer was designed for one purpose: to play LOUD! And loud it does. The peak in-car SPL output occurs at 40Hz which is also the port tuning frequency. With 1 watt input (2 volts rms into 2 ohms), the Rockford T212D4 generated a peak SPL of 112.2 dB in the minivan test vehicle. This is quite loud. Below the 40 Hz tuning frequency response, the output of the T212D4 dropped off rather quickly. The T212D4 has usable output down to 35 Hz.
Then next test measure the output level with 1000 watts (around 45V rms). What was impressive about this woofer is how easily it handled the power. At 40 Hz the SPL increased to an impressive 135.9dB. Even below the tuning frequency, the T212D4 suspension handled the power without complaint. Very impressive. At 2000 watts, the T212D4 again increased its SPL output. At 40 Hz, the Rockford woofer increased its output to 138 dB. However, below the tuning frequency, the woofer was showing signs of reaching its limit. At 20 Hz you could hear what sounded like the spider hitting the top plate of the motor structure. To be fair, the woofer was moving what appeared to be more than 3 inches peak to peak. I wanted to see if increasing the power could get even more SPL. I reached the limit of my amplifier at 80.4 volts rms unclipped. That is a whopping 3232 watts into a 2 ohm load! The SPL increased to 140.1 dB with no visible signs of mechanical woofer problems.
On the sound quality side, the bass sounded powerful (duh) but a little boomy. For long term reliability, I would recommend a subsonic filter on this system. The output and power control this woofer displayed was just impressive. Don’t buy this woofer if you listen to opera. That is unless you want opera to boom.
Summary
The T212D4 is a huge woofer. Huge in looks, huge in power handling and definitely huge in SPL output. At a MSRP of $699, the price is big too. Even when considering the price, the Rockford Fosgate T212D4 still definitely delivers the value. If you are looking for a woofer to handle even the most power amplifiers car audio has to offer, the Rockford Fosgate T212D4 is definitely on the short list.
4
out of 5
3
out of 5
