run my amp at 4ohm or 8ohm?

[toypaseo]

In continuing my "Budget Bass" project...

I have a Rockford Fosgate 401SP. It puts out 400x1 RMS at 4ohm, or 250x1 RMS at 8ohm.

Most of the 8" subs I have been considering peak at 300 watts.

• :shifty_ey Should I run a 4ohm sub, with the gains down to hopefully not blow the sub?
  
• :shifty_ey Should I run an 8ohm sub, so the amp is understressed?

Amp might be placed behind the rear panel by the factory sub location. The setup will not be pushed hard, maybe occationally but not daily.

 

[bigrizza]

i'm running a alpine v power amp 400x1 rms at 2ohms witha JL audio 12" that handles 300 rms hasn't blown yet. if you want to play it safe why not get a cheaper amp that has less rms instead of wasting the rockfords power?

 

[toypaseo]

Amp was bought for $50. I was looking at smaller amps, but then this one popped up on Craigslist. Came with an 8 gauge Lightning Audio install kit that was uninstalled from the previous owner's car, so that saved me a bit of money there also.

 

[lilbeefy]

run it at 4 ohms, you wont blow the sub. I am running two orion hcca's 10inch, with dual two ohm outputs, off an amp rated for 4000 watts at one ohm. i just dont push it to hard.

 

[Jason94sport]

More power is almost always better. Speakers are blown from under powering more then over powering.

 

[kb1cir]

run at the impedence of the speaker! fuse it if your worried about blowing it. DC current is generally what kills a speaker from a clipped (flat topped) waveform.

 

[toypaseo]

run at the impedence of the speaker! fuse it if your worried about blowing it. DC current is generally what kills a speaker from a clipped (flat topped) waveform.

Some of the subs I am looking at come in 4ohm or 8ohm. One 8ohm sub in particular is 230 peak watts, with the Rockford Fosgate amp putting out 250 at 8ohm. No worries there.

 

[410Fortune]

8ohm is likely dual voice coil, I would skip this and run 4 ohm.
DVC is just asking for problems

 

[toypaseo]

8ohm is likely dual voice coil, I would skip this and run 4 ohm.
DVC is just asking for problems

SVC 8ohm. I'll post two of the possible candidates...

 

[toypaseo]

GOLDWOOD GW-8PC-30-4 8" HEAVY DUTY WOOFER 4 OHM

The Heavy Duty PC Series is available in 4 ohm and 8 ohm versions for automotive and home audio applications. The woofers handle the most powerful of amplifiers while maintaining sonic excellence. They feature aluminum die-cast frames, knurled and gold-plated binding posts, rubber surrounds, and vented pole pieces with bumped back plates.

Specifications: * Power handling: 120 watts RMS/230 watts max * Voice coil diameter: 1-1/2" * Frequency response: 45-7,000 Hz * Magnet weight: 30 oz. * Fs: 45 Hz * SPL: 91 dB 1W/1m * Vas: 1.77 cu. ft. * Qms: 4.2 * Qes: .72 * Qts: .62 * Xmax: 3.21mm * Net weight: 5-1/4 lbs. * Dimensions: Overall Diameter: 8", Cutout Diameter: 7-1/8", Mounting Depth: 3-11/16", Magnet Diameter: 4", Magnet Height: 1-1/4".

 

[toypaseo]

DAYTON QT210-4 8" QUATRO SERIES SUBWOOFER 4 OHM

The Quatro™ Series subwoofers have been designed and built based on the well-respected platform of the Dayton Series II woofers. By implementing a 4 ohm voice coil and extending the excursion capabilities, the Quatro™ woofers now become serious contenders for home theatre and automotive use. The long excursion design and high sensitivity allows you to take advantage of modest power amplifiers, while the relatively high DC resistance makes them very friendly to 4-ohm stable amps and will not cause overheating or other amplifier stability problems.

Specifications: *Power Handling: 150 watts RMS/300 watts max *VCdia: 1.5" *Le: 2.2 mH *Znom: 4 ohms *Re: 3.90 ohms *Frequency range: 35-200 Hz *Magnet weight: 33 oz. *Fs: 36 Hz *SPL: 89.2 dB 2.83V/1m *Vas: .82 cu. ft. *Qms: 8.2 *Qes: .42 *Qts: .40 *Xmax: 9.5 mm *Dimensions: Overall Diameter: 8-1/4", Cutout Diameter: 7-1/4", Mounting Depth: 4".
Bumped Back Plate
-Heavy Gauge Stamped Steel Frame
-Santoprene® Rubber Surround
-Kevlar® Impregnated Coated Paper Cone
-Large 4-layer V.C. with Kapton® Former
-Vented Pole Piece

 

[toypaseo]

TANG BAND W8-740C 8" SUBWOOFER

The W8-740C is one of the highest excursion 8" subwoofers available on the market. It utilizes a heavy-duty paper cone, foam surround, and bumped back plate for maximum mechanical movement. The 2" 4-layer voice coil, vented pole piece, and heavy-duty aluminum voice coil former provide impressive power handling. Excellent for small-enclosure home or automotive subwoofers.

Specifications: Power Handling: 150 watts RMS/300 watts max *VCdia: 2" *Impedance: 4 ohms *Re: 3.2 ohms *Frequency range: 28-1,000 Hz *Fs: 28 Hz *SPL: 84 dB 2.83V/1m *Vas: .81 cu. ft. *Qms: 10.53 *Qes: .30 *Qts: .30 *Xmax: 12mm *Dimensions: A: 8-1/4", B: 7-1/4", C: 4-3/4"

 

[toypaseo]

Hmmm... maybe I should make a post to see what sub you guys would pick from those...

 

[410Fortune]

why 8"?

 

[toypaseo]

Fitting it in the stock JBL enclosure.

The 6" or 6½" subs I ran across don't handle alot of power :thumbdwn:

 

[410Fortune]

put a 10 in there

 

[toypaseo]

maybe... I am concerned about the cubic foot being too small for a 10" though...

 

[toypaseo]

put a 10 in there

410Fortune, suggest a bargain 10" sub...

 

[410Fortune]

mtx makes great entry level subs