Which amp should I buy

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BigBlue05

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I'm putting 2 Memphis Audio 15-SRX10D4
10" dual 4-ohm voice coil component subwoofers in my truck. Which amp should I go with and how many watts does it need to be.
 

justin13703

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The problem is that you are using two 4 ohm dual voice coil subs. So you will either need a 2 channel amp so that you get a 2 ohm load per subwoofer, and that amp needs to put out around 200w RMS per channel at 2 ohms. Or you will need a mono amp that puts out around 400wRMS at 4 ohms, which will be a pretty big amp. Running a 4 ohm load on an amp is just wasting power.

If you had two 2 ohm dual voice coil subs, you could use a mono amp that puts out around 400w RMS at 2 ohms which will be much cheaper than one that puts out 400w RMS at 4 ohms.
 

Bullitt5339

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He said they're 4 ohm DVC, so that would mean each woofer could be wired to 2 ohms or 8 ohms.

That would mean you can get away with any 500ish watt RMS amp @ 1 ohm, which are a dime a dozen and cheap.

I'm very partial to Sundown Audio. I used to work for them as a sales rep and the entire company is top notch.
 

WilliamS

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Rockford Fosgate never failed me. Never. You can complain all you want about their subwoofers, speakers, and so on, but amps Ive been running 20 years and never a failure
 

justin13703

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He said they're 4 ohm DVC, so that would mean each woofer could be wired to 2 ohms or 8 ohms.

That would mean you can get away with any 500ish watt RMS amp @ 1 ohm, which are a dime a dozen and cheap.

I'm very partial to Sundown Audio. I used to work for them as a sales rep and the entire company is top notch.

Yeah I know. Each sub is wired for a 2 ohm load. So with the combination he has, he will have to get a 2 channel amp to keep the total load per channel at 2 ohms. With a mono amp, he will either end up with 4 ohms or 16 ohms on that one channel.

Those subs are rated for around 200w RMS each. So to run both of them, you need an amp that puts out 400 watts RMS at the specified resistance. So if he ends up with a monoblock amp rated for 500w RMS at 1 ohm, it will not have nearly the power all the way up at 4 ohms.

To use a monoblock amp with his setup, he will end up with 4 ohms. To get a monoblock amp that is rated at 1 ohm to still output 400w at 4 ohms, he will need a pretty big amp, probably close to or over 1,000watts at 1 ohm. That's why I said his best option with what he has, is to get a 2 channel amp rated at 200 watts per channel at 2 ohms. Will be much cheaper, easier to find, and more efficient. There are a million ways to do it with wiring combinations, and different amps, but that is what I would do in his position. A 2 channel rated at 200 watts per channel at 2 ohms, and hook each sub up to its own channel.
 
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Bullitt5339

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Nah, the standard in Class D mono amps has pretty much changed to 1ohm optimized in the past few years. It's now pretty much expected, even in cheaper amps.
 
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justin13703

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Nah, the standard in Class D mono amps has pretty much changed to 1ohm optimized in the past few years. It's now pretty much expected, even in cheaper amps.

Well if he goes with a 1 ohm amp, if it's a monoblock it'll probably have to be around 1kw RMS. If it's a 2 channel, he will need to be around 500w RMS per channel.

Either way I definitely would not use a monoblock. That's a lot of wasted draw on the electrical system because it'll end up being 4 ohms.
 

Bullitt5339

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I think you're getting confused somewhere. A pair of dual 4 ohm subs wires to 1 ohm. You can get 500rms@1 ohm in something like a Hifonics for around $100.

A class D monoblock is more power efficient than the same wattage in a class A/B 2 channel.
 

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justin13703

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Yeah you're right. Back when I was doing installs 1 ohm amps weren't too common so I never had to wire em like that. Didn't even think about it. My mistake.
 

WilliamS

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Please for the case of cost vs value, spend the extra 50 bucks to get a name brand. Buying 2 crap ones because it goes bad will be more than 1 quality one.
 
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BigBlue05

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so ive been looking for 500w at 1 ohm amps and i cant seem to find any cheaper than around 300. Also what is the difference between 500w at 1 ohms and 500w at 2 ohms. Im not really familiar with car audio so sorry if thats a dumb question.
 

justin13703

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so ive been looking for 500w at 1 ohm amps and i cant seem to find any cheaper than around 300. Also what is the difference between 500w at 1 ohms and 500w at 2 ohms. Im not really familiar with car audio so sorry if thats a dumb question.

That's what I thought the problem was gonna be with a 1 ohm amp. Maybe Bullitt has some sources but at least when I was doing installs, 1 ohm stable amps were dumb expensive.

Ohms are a measurement of resistance. The more resistance, the less power you will actually get. An amp that puts out 500w RMS at 1 ohm will put out around 300-350 watts at 2 ohms, and maybe 200 watts at 4 ohms. Basically the output of your amplifier is dependant on the total resistance (ohms) on that channel. As resistance goes up, power output goes down, but resistance is basically wasted power and creates more heat.

A 2 channel amp that is rated at 200w RMS per channel at 2 ohms would be the next best option if you can't find a 1 ohm amplifier within your budget.

This one may still be more than you want to spend, but if you go the two channel amp route, these are the specs you want to look for.
https://www.sonicelectronix.com/item_67762_Rockford-Fosgate-Punch-P400X2.html
 
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Bullitt5339

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I'm not up on cheap amps, I tend to deal with bigly expensive crap, but a quick search in my database pulls up the Orion CB1000.1d for $94 on Amazon.
 

justin13703

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I'm all for buying good stuff too, but unless it's a high end build you can get away with most of the cheaper brand name ones like alpine, Kenwood and pioneer. I don't like kicker or Sony. Rockford is always a good one too but they're a little more money. Ive heard good stuff about sundown too but they're not cheap either. I've never used or heard of anything about Orion.

I've got two kenwoods in my truck. One for my sub, and one as a 4 channel. They're both about 7 years old and work and sound awesome. I got em on clearance when I was an installer for 25 dollars each. Lol
 
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Bullitt5339

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In 1990, I had a sponsorship from Orion for IASCA. I ran 0-50 watt class with 4 Orion XTR 12s and 12 other speakers. That was in the day of cheater amps and more efficient subwoofers. My 50 watt amp clamped at 650 watts rms at 1/8th ohm...

1994, I switched to Autotek in the same class with Kicker speakers.

Took a break, came back in 2004 running Memphis who were Fultron when I started.

In 2006, I secured a deal with Sundown Audio when they only made 2 amps and didn't do subwoofers at all. The owner of Sundown and Stereo Integrity we're great friends, so that led to a deal with SI until Sundown started making subs and SI went more towards SQ.

I was running Pro Trunk in NSPL most of the time and Pro 501-1000 in IASCA. I retired around 2013 because of all the drama in the car audio competition circuit and haven't had a system since. I am going to put a little something in the truck once I get everything else pretty much wrapped up.
 

justin13703

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Im willing to spend between 150 and 200 for an amp. How about this. What subs would work with this amp.http://www.crutchfield.com/p_575R500X1D/Rockford-Fosgate-R500X1D.html?tp=35834 The only reason i was gonna use those subs was because i was gonna buy them from a friend. But Im open to finding other subs as well.

2 subs? If so then any 2 ohm dual voice coil subs with an rms rating of 200-250 watts each would work fine

Personally myself I would just do a single 10 or 12" sub with a 500w rms rating in a ported box. The alpine type S subs are rated at 500w rms for example. SWS-10D4 is the model number for the 10" type S. Alpine type R and type S subs are good subs. I have a type R in my truck but the amp you linked will only power the type S. If you do a single, then you want a dual 4 ohm coil sub.
 
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BigBlue05

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The reason I'm doing 2 subs is because I already have a sub box that fits under my back seats. So I figure no use buying one to sit on the seat instead of 2 to fit under the seat.
 

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