Sub/amp help please

[squirrelishere]

Okay, I'm confused. Beyond confused. Reading so much and not knowing wtf is going on. My sub blew yesterday. After months, it finally blew. Anywho. I have an amp. This thing has been with me for years. Over 5 years now. And it's still going. The model is an MTX 421D. I need a sub, but I don't know what to look for really. I'm on a budget, also. Nothing more than 80. If I gotta go more, it'll have to wait. Here's some specs that I got off MTX's website that confused the heck out of me:

MTX 421D
• RMS Power measured at 12.5 Volts DC:
150 Watts x 1 into a 4 Ohm load with less than 1% Thd+N
300 Watts x 1 into a 2 Ohm load with less than 1% Thd+N
• Dynamic Power measured at 14.4 Volts DC:
210 Watts x 1 into a 4 Ohm load
420 Watts x 1 into a 2 Ohm load
• Signal to Noise Ratio: ?100dB A-Weighted
• Damping Factor: >100
• Frequency Response: 20Hz-200Hz ± 3dB
• Maximum Input: 8Vrms
• Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz
• Crossover: Variable 40Hz to 200Hz, 24dB/Octave Low Pass

If you need more info, let me know. I'm only running 1 sub. That's where I don't understand this whole ohm thing. These are the some subs I'm looking at. I'll put the link and specs in case you don't wanna click the link.

Alpine SWE-1042
http://www.crutchfield.com/App/Produ...SWE1042&tp=111

10" 4-ohm subwoofer
Kevlar®-treated pulp woofer cone
high-excursion Santoprene rubber surround
dual oversized Nomex® spiders
frequency response: 32-1,000 Hz
power range: 50-250 watts RMS
peak power: 750 watts
sensitivity: 87 dB

Infinity Reference 1050W
http://www.crutchfield.com/App/Produ...081050W&tp=111

10" 4-ohm subwoofer
polypropylene woofer cone with large-roll rubber surround
innovative basket design minimizes depth
progressive spider design for excellent cone control
frequency response: 25-400 Hz
power range: 60-250 watts RMS (1,000 watts peak power)
sensitivity: 91 dB

MTX MZS1004
http://www.onlinecarstereo.com/CarAu...roductID=18763

Sensitivity: 84.4 dB
RMS Power Range : 150 Watts
Peak Power Handling: 300 Watts
Impedance: 4 Ohm
Low Frequency response: 24 Hz
High Frequency Response: 150 Hz
Diameter: 10 Inch

And lastly:
MTX T4510-04
http://www.onlinecarstereo.com/CarAu...roductID=13308

Sensitivity: 87.6 dB
RMS Power Range : 50-225 Watts
Peak Power Handling: 225 Watts
Impedance: 4 Ohm
Low Frequency response: 35 Hz
High Frequency Response: 150 Hz
Diameter: 10 Inch

Are any of those compatible with my sub? I've had MTX and Infinity subs, and my bro has had Alpines and all 3 companies have been great for us for years. But I need a sub now and dying to know what the heck ohm means lol......... Help me out please. And no, I'm not thinking of getting a new amp. I'm broke, and no job. Thank you.

[ricehammer]

Ok - here goes. Any of those subs will work with your 421D. They're all 4 ohm subs and your amp is good down to 2 ohms.

Ohms, or better yet impedance for a fancy term, is a measure of the "AC resistance" of the speaker. AC resistance isn't a proper term as far as engineering goes, but it's good for analogy. If you look at the spec for your amp, you'll notice that it produces more power into a 2 ohm impedance as opposed to 4 ohm. This makes sense because the voltage at the speaker terminal is the same as with 4 ohms and more current will flow through the sub if it has a 2 ohm impedance.

If you really want to push some power, find a 10", 2 ohm sub. Just don't go below 2 ohms and you won't fry the power transistors in the amp.

Hope you're not more confused .

[squirrelishere]

Yep... still confused....

As long as the ones I'm looking at fall under safe subs for my amp, I'll pick one of those. I'm reading sites all over to try to understand this. I kind of get what you mean, but it's not going all the way through. I'm looking at numbers and see if I can understand that.

[nemocamaro]

the more ohms, the more resistance or power it takes to push the sub.


volts x amps = watts.

watts / ohms = loud music

[Maroon Z]

For full potential out of tham amp, look for a sub that has a single 2 ohm Voice coil, or a dual 4 ohm Voice coil. Should say something like SVC 2 ohm or DVC 4 ohm. I'm assuming your only buying 1 sub?

Also, what are you trying to accomplish? Something with superb sound quality, get loud, both?