What kind of amp with these subs?

O.D. Showtime

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Mar 31, 2002
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Assumming I run two JL Audio 10W0 subs (125 watts each of continuous power handling), then what kind of amp do I need without under or overpowering the subs? Also, the sub is available in 4ohm or 8ohm, what's better? I noticed many amps are available in 2 channel, 4 channel, etc. I have mach 460 and plan on upgrading to an Alpine headunit in the future and new door and rear speakers. So I don't want to get an amp that's gonna be useless with those add-ons in the future. Thanks.
 
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Well, there are several ways to go when adding two subs, you could get a 2 channel amp to power the subs, or you could get a mono amp, and wire both subs on the same channel. If you went this route, it would look something like this... http://www.crutchfieldadvisor.com/S.../subwoofers_wiring.html?subs=2&impedance=SVC8

Stick with main brands, no off brand, and a general rule of thumb is you should pay at least $1 a watt (rms) in 4 ohm, or you are buying crap.

As for the alpine unit and new speakers, i am a little confused about your question, do you want the head unit to power the speakers, or do you want to get another amp to power the speakers? If you want to get one amp to run your whole system, and have the head unit power nothing, then just get a nice 5 channel amp, most of them are set up as follow: 40 x4 and 200x1. That will cost you a lot of money though. Its probably cheaper to get two amps, one for the subs, one for the 2 sets of speakers. If you are planning on running the door and rear speakers off of the head unit, then it doesnt matter what kind of amp you get.
 
MyEarsHurt said:
Well, there are several ways to go when adding two subs, you could get a 2 channel amp to power the subs, or you could get a mono amp, and wire both subs on the same channel. If you went this route, it would look something like this... http://www.crutchfieldadvisor.com/S.../subwoofers_wiring.html?subs=2&impedance=SVC8

Stick with main brands, no off brand, and a general rule of thumb is you should pay at least $1 a watt (rms) in 4 ohm, or you are buying crap.

As for the alpine unit and new speakers, i am a little confused about your question, do you want the head unit to power the speakers, or do you want to get another amp to power the speakers? If you want to get one amp to run your whole system, and have the head unit power nothing, then just get a nice 5 channel amp, most of them are set up as follow: 40 x4 and 200x1. That will cost you a lot of money though. Its probably cheaper to get two amps, one for the subs, one for the 2 sets of speakers. If you are planning on running the door and rear speakers off of the head unit, then it doesnt matter what kind of amp you get.

Alright, here is what I think I'm gonna do, assumming it'll work. I am not looking to spend a tremendous amount of money on this system, I just want something better than stock. I suppose I'll get an Alpine head unit ( http://www.crutchfield.com/S-dvH7cz8QbfY/cgi-bin/ProdView.asp?I=500CDM9821) w/ a built in amp, so i can run the front/rear speakers. The amp will have preamp outputs and is labeled at 16 watts RMS/45 peak X 4 channels. I will use the two JL Audio 10W0 subs (http://www.acaraudio.com/product_info.php?cPath=24_48&products_id=161), available in a 4ohm or 8ohm option (which is better for my setup?), and a continuous power handling of 125 watts. I will use an Alpine amp (http://www.crutchfield.com/S-dvH7cz8QbfY/cgi-bin/ProdView.asp?I=500MRPF240). The amp is a 4 channel, capable of 4 ohm in a bridged mode. You can click on the links for the items to look at all of the details. I figure I'll use the amp in the headunit to power the front speakers, and then have the 4 channel amp bridged to run the rear speakers and then subs....will this work??? The reason I don't want to use headunit's amp for all the door/deck speakers is b/c I heard it disables the fade mode, whereas you can adjust from rear to front speakers and what not. I don't know car audio at all, I just decided to search the internet and see if this stuff is compatible together. Based on what I have presented to you, does it seem like this system will work, any suggestions or any ideas? Will the subs be underpowered? I know it's a lot of questions, but I figured I'd ask someone who is knowledgeable on the subject. If you can help, it'd be great. Thanks.
 
jl audio e1200 monoblock amp or alpine or maybe a rockford p3001. them w0s are nice subs, get them in 4ohm. dont use that 4 channel amp to power your subs, its not enough. as far as losing fade and balance, thats not true, you wont lose it. i would use that amp you posted to power my 4 speakers than use an amp that i mention above (or somethign close enough) and step it up to at least an alpine 9825, the one you posted only has one set of pre outs, you could only power 2 subs. the 9825 and above will have pre outs for a 4 channel and a subwoofer amp. (but will cost you a 100 bucks more)
 
4.6litrebeater said:
jl audio e1200 monoblock amp or alpine or maybe a rockford p3001. them w0s are nice subs, get them in 4ohm. dont use that 4 channel amp to power your subs, its not enough. as far as losing fade and balance, thats not true, you wont lose it. i would use that amp you posted to power my 4 speakers than use an amp that i mention above (or somethign close enough) and step it up to at least an alpine 9825, the one you posted only has one set of pre outs, you could only power 2 subs. the 9825 and above will have pre outs for a 4 channel and a subwoofer amp. (but will cost you a 100 bucks more)

If I decide to just use the 9821 headunit will it be enough to power Infinity Kappa front and rear speakers? If I can just get away with using the amp in the headunit to power the front/rears then i'll do that, or will it sound like crap if I don't power it by an external amp?
 
First off I wouldnt get that amp to power the subs and the speakers. I have infinity kappa series and they sound awesome, even if they are only gettng like 20 watts rms. I would say find a different amp to power the subs, and only power the subs with that amp. It would probably be MUCH easier, and weight and cost a lot less if you just went with 1 12" JL sub with like 250-300 watts rms. That will give you all the bass you are looking for. Then you can just get a mono amp. Thats the way I would go....i mean if you got something like this instead ....http://www.acaraudio.com/product_info.php?cPath=24_47&products_id=1131

Thats 300 wrms, and you could get any mono amp that pushes 300 watts rms or even 250 wrms. It would save on trunk space, and it would still sound just as good if not better than the 2 10's at 125 rms a piece.
 
MyEarsHurt said:
First off I wouldnt get that amp to power the subs and the speakers. I have infinity kappa series and they sound awesome, even if they are only gettng like 20 watts rms. I would say find a different amp to power the subs, and only power the subs with that amp. It would probably be MUCH easier, and weight and cost a lot less if you just went with 1 12" JL sub with like 250-300 watts rms. That will give you all the bass you are looking for. Then you can just get a mono amp. Thats the way I would go....i mean if you got something like this instead ....http://www.acaraudio.com/product_info.php?cPath=24_47&products_id=1131

Thats 300 wrms, and you could get any mono amp that pushes 300 watts rms or even 250 wrms. It would save on trunk space, and it would still sound just as good if not better than the 2 10's at 125 rms a piece.

Maybe I'll consider just one sub, the main reason as to why I wanted two subs is b/c of the fact that I'll have a bigger box to mount the amps to. That's the way I wanted to do it, I don't feel like drilling holes into the back of my seat, so I was just gonna put both amps on the sub box but if I only have a box for one 12" sub then it might not fit the amps. Anyways, so are you saying having a head unit w/ a built in amp is good enough and powerful enough to run the front/rear speakers?...then just use a mono amp for the sub?
 
Thats what I did for a long time probably like 9 months, then I got a 4 channel amp to power the speakers just because I couldnt hear the speakers over the bass (note: that probably wont happen to you unless you have over 700 wrms to the sub). But if you have stock speakers now and you are going to infinity kappa series, you will be really happy with the change, even if the speakers are powered by the head unit.
 
I would recommend against using a bridged amp of any kind to power a sub. It's just not necessary with all the nice mono amps available. With bridging an amp you get into shared power supplies and such things sometimes and it is just better to NOT do that with a sub system if you don't have to. Plus, it's hard on the amp. More so if it is of mediocre quality. Bridging for "main speakers" is not so bad sometimes if you have an amp already and want to make do with what you have. It sounds as though you want a simple, clean sounding system. I suggest you buy one pair of very nice components, install them properly up front, and the system will be more "correct" for imaging and soundstage. Rear speakers add nothing to a system. A nice component set with w0/w0s with everything amplified CORRECTLY would make a very nice BALANCED system. A mono amp of 250-300 watts into 2 ohms would be nice for two 4 ohm w0s in parallel. And a proper amp for the components(depending on what you would buy) would be all you need and you would be set. A final comment; HUs are not suited for high volume use. If they were, we wouldn't need separate amps. The amp in a HU is lacking in the power supply department, so unless you are intending to always listen at low to mid volume levels, I would say an amp is necessary, especially with the components. Just my opinions. Good Luck!!
 
The guy from Crutchfield told me I can't run Kappas off the Alpine headunit, that I need an external amp. But this isn't what everyone else is telling me. I figure if I can run the front speakers off the headunit amp, that'll be fine, then use a 4 channel amp to run one 12" sub and the rear speakers. The crutchfield guy also told me to purchase these: http://www.crutchfield.com/S-Wzw0BB...119IHPY1F&o=p&a=0&cc=01&avf=N&search=splitter
, which would allow me to run two subs (if i wanted to) from the 4 channel amp b/c it would split channels. With this setup, he insists I can have one 4 channel amp and split channels to run two subs, then use the remaining channels for the front/rear speakers.
 
Bloomy316 said:
I would recommend against using a bridged amp of any kind to power a sub. It's just not necessary with all the nice mono amps available. With bridging an amp you get into shared power supplies and such things sometimes and it is just better to NOT do that with a sub system if you don't have to. Plus, it's hard on the amp. More so if it is of mediocre quality. Bridging for "main speakers" is not so bad sometimes if you have an amp already and want to make do with what you have. It sounds as though you want a simple, clean sounding system. I suggest you buy one pair of very nice components, install them properly up front, and the system will be more "correct" for imaging and soundstage. Rear speakers add nothing to a system. A nice component set with w0/w0s with everything amplified CORRECTLY would make a very nice BALANCED system. A mono amp of 250-300 watts into 2 ohms would be nice for two 4 ohm w0s in parallel. And a proper amp for the components(depending on what you would buy) would be all you need and you would be set. A final comment; HUs are not suited for high volume use. If they were, we wouldn't need separate amps. The amp in a HU is lacking in the power supply department, so unless you are intending to always listen at low to mid volume levels, I would say an amp is necessary, especially with the components. Just my opinions. Good Luck!!

Thanks for the info, what I was trying to do was to get away with using just one amp. As is mentioned in my other post, the guy from crutchfield mentions using a monster cable to split one channle into two, which if more than one cable is used, I suppose it would make it possible to run everything in my car off one amp. But does this overload the amp or is sound quality going to be sacrificed?
 
O.D. Showtime said:
The guy from Crutchfield told me I can't run Kappas off the Alpine headunit, that I need an external amp. But this isn't what everyone else is telling me. I figure if I can run the front speakers off the headunit amp, that'll be fine, then use a 4 channel amp to run one 12" sub and the rear speakers. The crutchfield guy also told me to purchase these: http://www.crutchfield.com/S-Wzw0BB...119IHPY1F&o=p&a=0&cc=01&avf=N&search=splitter
, which would allow me to run two subs (if i wanted to) from the 4 channel amp b/c it would split channels. With this setup, he insists I can have one 4 channel amp and split channels to run two subs, then use the remaining channels for the front/rear speakers.


First off the kappas will be fine going off of the head unit. The setup you had in mind with the 4 channel amp would work but probably wouldnt sound that great or be that loud. Honestly, I would say get 1 or 2 subs and get a mono amp to power the subs. Then down the line if you want to add a 4 channel amp to power the door speakers and the rear speakers, then go for it, just make sure when you are wiring the first time you overcompensate and get a 4 gauge wire, that way if you want to expand in the future, it will be that much less work.
 
O.D. Showtime said:
The guy from Crutchfield told me I can't run Kappas off the Alpine headunit, that I need an external amp. But this isn't what everyone else is telling me. I figure if I can run the front speakers off the headunit amp, that'll be fine, then use a 4 channel amp to run one 12" sub and the rear speakers. The crutchfield guy also told me to purchase these: http://www.crutchfield.com/S-Wzw0BB...119IHPY1F&o=p&a=0&cc=01&avf=N&search=splitter
, which would allow me to run two subs (if i wanted to) from the 4 channel amp b/c it would split channels. With this setup, he insists I can have one 4 channel amp and split channels to run two subs, then use the remaining channels for the front/rear speakers.


Probably what the Crutchfield rep meant was that the Kappas won't perform up to their capabilities with a HU, which is absolutely true. But you can certainly do it until you can get an amp, if you decide to go that route. As I mentioned before, HUs just don't cut it for amplifying quality speakers at anything above an average listening level. They will work, just not well, in comparison to what a quality amp will provide. I have a 5 channel Hifonics amp in my truck that is 50x4 and 200x1 RMS. It will play as loud and clean as I can stand it for as long as I want. I have a quality component set and a pair of subs, and it sounds great. I went for sound quality, not SPL. It's balanced well. I don't go for the big boom, so it fits my needs perfectly. Maybe something like that would be what you are looking for. They are all over ebay for $209, brand new. Mine entire system has been trouble free for almost 3 years. I took my time on the installation and didn't cut corners and have never been sorry. That means a lot as a matter of fact. You can buy some really nice equipment and do a crummy install, and get crummy results.
 
I'll offer up a couple of sugesstions to look at!

First off if you are not into spending that much you are better off powering your fronts/rears with the HU for now. That way you can focus on not going too cheap on the subs and sub amp. Save up and get a nice 4ch amp for the kappas later.

Here's my suggestion for subs and sub amp:
Go with a 400W RMS setup for starters. That's some decent bass power that can be had for under $400 with decent quality parts.

Get a mono amp. These are Class D amps that designed for running subs. They are more efficient, draw less current and produce less heat than multi channel amps. They have more distortion than multichannels but that's ok since they are driving sub bass frequencies where distortion is not easy to hear. Here are 2 decent amps that produce 400W x 1 @ 2ohms:

Kicker 04KX400.1
Kenwood KAC-8151D

For subs you are going to want to match the RMS power rating of the amp that is powering them as close as you can. I've always been a fan of Rockford Fosgate subs and here's a couple suggestions:
If you want a single 12" sub check out this one:
Rockford Fosgate RFP4212 12" DVC Sub
If you are still set on having two 10's then give these a shot and wire them in parallel for a 2ohm load:
Rockford Fosgate RFP4410 10" SVC Sub

Either of those amps with either choice of sub will get you what you are looking for for under $400 (not including the enclosure). A good deal IMHO.

Don't forget to follow the advise of MyEarsHurt on the wiring and I might also add that you'll want to install a power distribution block (such as this one) as well so you will be set for adding power to additional amps in the future.
 
I have 6 JL w0 and i use 3 300/1 JL amp.. Which gives me 150 By 6.. It says that can handle 125 i think its more like 200... IF you want some nice highs go for the new Bostons... I have 2 other 300/1 JL amps for them... 300 to each set of componets... The reason why i am using all JL amps is because i got all 5 amps for 1000 bucks... And they work really well.. Dont over heat and never cut out.. I wouldnt get an Alpine headunit.. I have had my share of headunits and i found that Apline had alot of problems... I would go with Eclpise... Well thats my .02.. Take it or leave it..
 
Mystifier said:
I'll offer up a couple of sugesstions to look at!

First off if you are not into spending that much you are better off powering your fronts/rears with the HU for now. That way you can focus on not going too cheap on the subs and sub amp. Save up and get a nice 4ch amp for the kappas later.

Here's my suggestion for subs and sub amp:
Go with a 400W RMS setup for starters. That's some decent bass power that can be had for under $400 with decent quality parts.

Get a mono amp. These are Class D amps that designed for running subs. They are more efficient, draw less current and produce less heat than multi channel amps. They have more distortion than multichannels but that's ok since they are driving sub bass frequencies where distortion is not easy to hear. Here are 2 decent amps that produce 400W x 1 @ 2ohms:

Kicker 04KX400.1
Kenwood KAC-8151D

For subs you are going to want to match the RMS power rating of the amp that is powering them as close as you can. I've always been a fan of Rockford Fosgate subs and here's a couple suggestions:
If you want a single 12" sub check out this one:
Rockford Fosgate RFP4212 12" DVC Sub
If you are still set on having two 10's then give these a shot and wire them in parallel for a 2ohm load:
Rockford Fosgate RFP4410 10" SVC Sub

Either of those amps with either choice of sub will get you what you are looking for for under $400 (not including the enclosure). A good deal IMHO.

Don't forget to follow the advise of MyEarsHurt on the wiring and I might also add that you'll want to install a power distribution block (such as this one) as well so you will be set for adding power to additional amps in the future.

Alright, cool...I think I'll go w/ the RF 12 and the Kicker mono amp. I'll also order the Kappas, and for now I'll just run them off a headunit (either an Alpine or Kenwood). Maybe in the future I'll get a four channel amp for them, but I don't want to spend too much right now. My last question for now, what kind of box do I need for the 12" sub? I'd see the point in making one but alot of single 12" sub boxes go for 20 bucks on ebay, which is about the cost in materials to make one, so why not buy one? Is this a good box: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50568&item=5716516955&rd=1
 
Sweet! I think you'll really enjoy that setup. I've been running around with the 2000 model of that same sub since it came out. I chose to put it in a sealed box simply because it was my first attempt at building a box and it was the easiest. Ported would definitely be a lot louder but with a slight loss in sound quality. It's up to you really what you want to use. That box on eBay is a bandpass box. I had a bandpass in the past with two 10's in it and it was ok. You might want to take a look at the manual for that sub. Rockford briefly explains about sealed and ported in the manual and gives their recommended dimensions for the box as well. Check it out in PDF format by clicking HERE

You might also want to check out the Rockford forums and see what people recommend over there: http://www.rockfordfosgate.com/forum/
 
Mystifier said:
Sweet! I think you'll really enjoy that setup. I've been running around with the 2000 model of that same sub since it came out. I chose to put it in a sealed box simply because it was my first attempt at building a box and it was the easiest. Ported would definitely be a lot louder but with a slight loss in sound quality. It's up to you really what you want to use. That box on eBay is a bandpass box. I had a bandpass in the past with two 10's in it and it was ok. You might want to take a look at the manual for that sub. Rockford briefly explains about sealed and ported in the manual and gives their recommended dimensions for the box as well. Check it out in PDF format by clicking HERE

You might also want to check out the Rockford forums and see what people recommend over there: http://www.rockfordfosgate.com/forum/

Alright, I'll prolly end up building a box myself then off of what the manufacturer recomends. Before I confirm my order online for all this stuff I just wanted to know what you all think the best option is for the Infinity Kappa speakers. I was going to order the 52.5i 5 1/4" speakers which have a rms power handling of 55 watts. I'm probably just gonna ditch the rear speakers for now and just run front ones, then get some rears in the future when i get a 4 channel amp for the infinities. But anyways, it's safe to run those off of a headunit, correct?
 
I dont know any head units on the market that put out over 55 watts rms per channel, so yes you are okay to run those off of the head unit. You will love em, you may need some dynamat though around them cause they are loud and the midrange is just awesome, but it may rattle a little in the door. Use a door kit, dynamat extreme.