Help selecting 12” sub-woofer and 5 channel amp

[bronchole]

Help selecting 12” sub-woofer and 5 channel amp

So I made a not-so-stealth 12" sub box a while back and I am ready to do a slight upgrade to it. I need to put the 12” sub-woofer I have been running back in to its original enclosure and install it in my son’s car so I am researching the replacement for it. I think this would make a great step up: Rockford Fosgate R1S4-12. While I am playing with things I wanted to install a 5 channel amp to really get things rocking. Here is the one I was thinking of using: Rockford Fosgate R600X5 5 channel amp. It looks to have just the right output for the sub-woofer and should drive my Infinity door speakers to their potential. I just hope the amp is slim enough to mount under the back seat because I would like to mount a sine power inverter where the current amp is.

What do you all think?

Dan

Specs:

Amplifier Rated Power :
(RMS Continuous Power): 50 Watts x 4 + 200 Watts x 1 @ 4-Ohms
75 Watts x 4 + 300 Watts x 1 @ 2-Ohms

Sub-Woofer Power Handling (4 ohm single voice coil):
(Watts RMS): 200 Watts RMS
400 Watts Max

Infinity door speakers (4 ohm):
RMS Power Range (Watts) 2-60
Peak Power Handling (Watts) 180

 

[bronchole]

Looks like Amazon has the best price on the amp at $226

and $57 for the sub-woofer.

 

[DjDom]

That amp has a dedicated 2 OHM subwoofer out. So, 300 Watts @ 2 OHMs.
So roughly 200 Watts @ 4 OHMs.

Sounds like a decent match up assuming they're listing RMS not Max output.

You should be happy with it. However, I prefer running a separate dedicated amp for the subwoofer, but if you want a well rounded system, that amp will serve you well.

 

[Anime]

Yeah, the amp sub channel is rated for 200W @ 4 ohms and that sub is rated at 150W @ 4 ohms, so you should probably get a 12" sub that can handle the 200W load.

 

[bronchole]

Amplifier Rated Power :
(RMS Continuous Power): 50 Watts x 4 + 200 Watts x 1 @ 4-Ohms
75 Watts x 4 + 300 Watts x 1 @ 2-Ohms

Sub-Woofer Power Handling (4 ohm single voice coil):
(Watts RMS): 200 Watts RMS
400 Watts Max

Infinity door speakers (4 ohm):
RMS Power Range (Watts) 2-60
Peak Power Handling (Watts) 180

So would I be better off looking at the 2 ohm variety of the sub woofers?

 

[bronchole]

Yeah, the amp sub channel is rated for 200W @ 4 ohms and that sub is rated at 150W @ 4 ohms, so you should probably get a 12" sub that can handle the 200W load.

I think you were looking at the specs for my old sub-woofer.

 

[bronchole]

So here is a dual 4 ohm sub-woofer Rockford Fosgate R2D4-12. That should be able to be wired in parallel to get it down to 2 ohms. Here are the power specs for it:

Power Handling (Watts RMS): 250 Watts RMS
500 Watts Max

The amp should be able to drive it to 300W at 2 ohms, which I am OK with the ability to slightly drive it beyond its RMS rating.

Does this look like a better fit than the other sub-woofer?

 

[Big_Pezzy]

If the budget allows it, i would upgrade the woofer to a Punch P1. it will handle those 300 watts nicely and sound better(Not just louder), if the amp is properly tuned of course. But in the end, if you only want ONE woofer, make sure it has a 2 ohm voice coil or is a dual voice coil with each being 4 ohms. the price is usually the same.

 

[Anime]

I think you were looking at the specs for my old sub-woofer.

The one you linked on Amazon is different than the one linked in your post:

This item: Rockford Fosgate Prime R1S412 R1 12-Inch 150 Watt Subwoofer - 4 Ohm

Rockford Fosgate also says that one is 150 watts:

R1S412
12" Prime 4-Ohm SVC Subwoofer

Rockford Fosgate Prime 12” subwoofers provide high performance bass at an unbelievable value. The R1S412 features a Single Voice Coil design, 150 Watt RMS power handling, and work great in sealed enclosures.

The R1S412 (150 Watts) isn't the same thing as the R1S4-12 (200 Watts).

Stupid to have a dash be the difference between two completely different models.

Be sure you buy the one you're after.


I wouldn't suggest driving a 150W rated sub with 200W or a 250W rated sub with 300W. It's "only 50 watts" but it's a big chunk of power when the rating is that low.

Driving a sub over the rated wattage voids the warranty and you can pretty much count on blowing it.


I'd definitely suggest the 200W RMS sub @ 4 ohms and the amp with a sub channel at 200W @ 4 ohms. Nice match.

If you're going to get a sub to drive with the amp at 300W @ 2 ohms, get a sub that handles 300W @ 2 ohms.

 

[bronchole]

Anime: Nice catch on the amazon link, and I agree, pretty stupid way to make a different part number. I fixed the link in the post to point to the correct one.

Big Pezz: The P1S2-12 has a 250W RMS to the R1s4-12's 200W so I am guessing you are talking about the P2D4-12 which is rated at 400W RMS.

Am I better off under driving a sub woofer, driving it right to its capacity or slightly overdriving it? My very limited experience and research lead me to believe that driving right to capacity was the way to go with slight over drive being more acceptable than significant under drive. But that is why I am asking.

I defiantly want to stick with a 5 channel amplifier. This is a wheeling rig so I need to bury the amplifier under the back seat so it stays out of the way of camping gear. If there is another 5 channel amp I should be looking at to get more kick out of it point me in the correct direction.

Thanks for the input guys.

Dan

 

[Anime]

If you underdrive a sub, you will usually get longer life from it, but it will underperform and not move as much air, so you will get less bass. If you match an sub and amp with the same RMS rating, you usually get the idea balance and the sub will perform as designed, without any effect to it's normal lifespan. If you overdrive a sub, it can sometimes get more output from longer excursion, but it will stress the components and lead to premature failure.

Slightly overdriving a sub with an amp that is rated higher is a school of thought that applies when companies overrate the output of their amps. When an amp only really puts out 100W RMS but is rated at 300W for marketing purposes, you are better off using it with a sub that rated at 100W RMS. Companies that make cheap audio gear like Boss, Pyramid, etc. are notorious for this.

I would guess that using a RF amp and matching RF sub, you'd want to match the two and won't have this issue since you're not buying a cheap amp.

 

[Big_Pezzy]

Rockford amps usually do more than what they are rated at. for example one of their 500 watt prime series amps might actually output 600. So if you wanted the P2, go ahead. I would suggest the P1 because it is a little cheaper and closer to the rated output of the amp(300 watts). It is better to have the amp have a higher output than need instead of a lower out put. This way you don't have to turn the gain as high. As long as you know how to properly adjust an amp, everything will be fine and you will not blow your speakers

 

[bronchole]

Thanks for all the input guys.

So assuming I am set on the RF 5 channel amp it sounds like my best bet is to go with the P2D4-12 listed at Amazon for $97 and wire it for a 2 ohm load.

That sound right?

Now I got to see if it will fit in my enclosure!

 

[Big_Pezzy]

Sounds good to me! An install write up would be nice it's an excuse to post plenty of pictures of your system and vehicle

 

[bronchole]

 

[DjDom]

Please use 2 Gauge wire.

Sounds like the setup will work. Good catch by Anime.

Why do you want to wire up the 4 ohm sub in 2 ohms?

 

[Big_Pezzy]

some QUALITY 4 gauge wire will be fine (assuming your battery and alternator are in good condition) Most important thing is to make sure the amp had a secure ground connection. I would also suggest running the RCAs on the opposite side of the power wire. Running them on the same side can cause signal interference

 

[bronchole]

Please use 2 Gauge wire.
Why do you want to wire up the 4 ohm sub in 2 ohms?

This was actually a question I was asking. Am I better off with a sub woofer at 2 ohms so I can pull the 300W out of the amp or 4 ohms so the amp drives at 200W. All assuming the RMS rating of the sub-woofer will be equal to or higher than the RMS output of the amp. The conclusion I took from this discussion was that I should go with the 2 ohm setup so that I can take advantage of the extra 50% or power it will suck from the amp.

Basically, nobody said don't do it or gave me any other input to sway me from this path.

 

[bronchole]

some QUALITY 4 gauge wire will be fine (assuming your battery and alternator are in good condition) Most important thing is to make sure the amp had a secure ground connection. I would also suggest running the RCAs on the opposite side of the power wire. Running them on the same side can cause signal interference

Right now I am using some very nice, very fine conductor 4GA wire from the battery in the front to a binder post in the back. Same wire is running to the amp from the binder post and from the amp to the frame rail. I have a nice cleaned area on the frame and I am using star washers. .

In the near future I am considering a second battery located underneath where the spare tire normally goes. At that point positive and negative will both run from the amp straight to that battery. Nice short run, maybe 3' max. The current run going from the battery in front to the binder post in back will run thru a 300A solenoid up near the front and to the second battery for charging.

I like having 2 batteries in my wheeler. It is a backup battery for out in the middle of nowhere and also the second battery my readywelder need if I have to do some welding on the trail.

 

[Big_Pezzy]

seems as though your electrical system will be fine. I too am planning on putting a second battery in the back once I install another amp and a light bar. To answer your further questioning of the subs, I would suggest to have the woofer wired to 2 ohms because you know the amp will output atleast 300 watts. Rockford has quality gear so no need for worries on under powering the sub