What Amplifier to get?

[ohJey]

I'm looking to get two of these http://www.amazon.com/Rockford-Fosgate-P2D2-12-400-Watt-Subwoofer/dp/B004UFHXHE/ref=sr_1_7?ie=UTF8&qid=1417383019&sr=8-7&keywords=p12+rockford

800w RMS, 1600w peak combined

I don't know much about amps, but I'm pretty sure it's best if you stay a little under the subwoofers RMS (to avoid blowing them)

 

My cars alternator is only 85Amps (~1000watts of output minus ac lights etc), so I'm probably going to need a capacitor for when the subs are cranked up

 

any help is appreciated

[Guest]

You can blow woofer with weaker amp if you don't know where to stop. I personally prefer to have stronger amp... Just find one in price range and that looks good (and that is made by good manufacturer ofc).

When you find something that you like please post it here

[xox]

I would go for an 800w amp to be honest, it will still drive the speakers.

[Lutkeveld]

IMO anything more than ~500W here is for bragging rights. Doubling it will cause only 1-2dB due to serious power compression.

 

Do you already have a box in mind? Because that makes or breakes a sub.

 

I think this thread is better of in the audio subforum.

[Jumper118]

I'm looking to get two of these http://www.amazon.com/Rockford-Fosgate-P2D2-12-400-Watt-Subwoofer/dp/B004UFHXHE/ref=sr_1_7?ie=UTF8&qid=1417383019&sr=8-7&keywords=p12+rockford

800w RMS, 1600w peak combined

I don't know much about amps, but I'm pretty sure it's best if you stay a little under the subwoofers RMS (to avoid blowing them)

 

My cars alternator is only 85Amps (~1000watts of output minus ac lights etc), so I'm probably going to need a capacitor for when the subs are cranked up

 

any help is appreciated

get 1 1000w amp, you dont have to turn it up all the way to max. you are better off getting 1 or 2 more batteries than a cap, as they are shoddy. if you have to have 2 go with 2 subs but 1 sub with a 500w amp should be enough to make your ears bleed.

[ohJey]

You can blow woofer with weaker amp if you don't know where to stop. I personally prefer to have stronger amp... Just find one in price range and that looks good (and that is made by good manufacturer ofc).

When you find something that you like please post it here

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

I would go for an 800w amp to be honest, it will still drive the speakers.

 

IMO anything more than ~500W here is for bragging rights. Doubling it will cause only 1-2dB due to serious power compression.

 

Do you already have a box in mind? Because that makes or breakes a sub.

 

I think this thread is better of in the audio subforum.

I'm going to make the box using Rockford Fosgates design

get 1 1000w amp, you dont have to turn it up all the way to max. you are better off getting 1 or 2 more batteries than a cap, as they are shoddy. if you have to have 2 go with 2 subs but 1 sub with a 500w amp should be enough to make your ears bleed.

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

Are you sure I'll need another battery?  The alternator should be able to power it fine, right?  I was just thinking about getting a 2 Farad cap just in case and I probably wont be using more than 500w from the subs during standard use

[Jumper118]

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

 

I'm going to make the box using Rockford Fosgates design

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

Are you sure I'll need another battery?  The alternator should be able to power it fine, right?  I was just thinking about getting a 2 Farad cap just in case and I probably wont be using more than 500w from the subs during standard use

you can't under power a nice sub like that, you will kill them very quickly, its like buying a cheap psu for your pc. the alternator should be fine with a second battery because you aren't going to be maxing them out for long periods of time. 

[simson0606]

get 1 1000w amp, you dont have to turn it up all the way to max. you are better off getting 1 or 2 more batteries than a cap, as they are shoddy. if you have to have 2 go with 2 subs but 1 sub with a 500w amp should be enough to make your ears bleed.

even extra batteries wouldn't help in every case, you still have to make the power before you can store it, so it would work if you only play it loud sometimes, not all the time.

 

you're right though a cap wouldn't make any difference

[Guest]

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

 

I'm going to make the box using Rockford Fosgates design

http://www.amazon.com/Rockford-Fosgate-Prime-channel-Amplifier/dp/B004T166L8/ref=sr_1_44?s=car&ie=UTF8&qid=1417165215&sr=1-44&keywords=car+amplifier

Are you sure I'll need another battery?  The alternator should be able to power it fine, right?  I was just thinking about getting a 2 Farad cap just in case and I probably wont be using more than 500w from the subs during standard use

That amp should be good. As for cap and battery I would add just one 1F cap but that's really optional.

[Lutkeveld]

 

you can't under power a nice sub like that, you will kill them very quickly, its like buying a cheap psu for your pc. the alternator should be fine with a second battery because you aren't going to be maxing them out for long periods of time. 

 

You can't really compare that. Power draw of a sub can't exceed the supply (amplifier).

 

I'm going to make the box using Rockford Fosgates design

 

Most of the times those are big and overtuned (one note bass)

Do you want it linear or with a small peak in the response? I can probably simulate a better and smaller enclosure for you.

 

A capacitor can't fix a crap battery. Because of the limited power supply I'd go with underpowering the subs.

Underpowering sound bad, but in reality you're saving a lot on cost and consumption, while your SPL won't decrease noticeably.

As you probably know: doubling power results in 3db. 3dB is a noticable difference, but you need 6 - 10 dB increase to sound twice as loud.

The difference between 400 and 800W will only be around 1-2dB (due to powercompression) which is almost unnoticable.

[ohJey]

 

 

 

You can't really compare that. Power draw of a sub can't exceed the supply (amplifier).

 

 

Most of the times those are big and overtuned (one note bass)

Do you want it linear or with a small peak in the response? I can probably simulate a better and smaller enclosure for you.

 

A capacitor can't fix a crap battery. Because of the limited power supply I'd go with underpowering the subs.

Underpowering sound bad, but in reality you're saving a lot on cost and consumption, while your SPL won't decrease noticeably.

As you probably know: doubling power results in 3db. 3dB is a noticable difference, but you need 6 - 10 dB increase to sound twice as loud.

The difference between 400 and 800W will only be around 1-2dB (due to powercompression) which is almost unnoticable.

 

Oh okay thanks for the explanation

I think I'd like a more linear response (meaning decent bass at all frequencies, right?)

[ohJey]

That amp should be good. As for cap and battery I would add just one 1F cap but that's really optional.

Hmm ok thanks

[Lutkeveld]

Oh okay thanks for the explanation

I think I'd like a more linear response (meaning decent bass at all frequencies, right?)

 

Yes, by overtuning it a little you can get a little bump at, say, 30hz. 

You can see it as a free bass boost at a certain frequency in exchange for a slightly less deeper bass response.

Can you give me a link to the box you were planning on using? I'll run the specs trough WinISD and see what it comes up with.

[Guest]

Oh okay thanks for the explanation

I think I'd like a more linear response (meaning decent bass at all frequencies, right?)

If you want more linear response than go with enclosure without some special gain. If you want more "kick" at lower volumes(loudness) (99% of time) just shrink that box you found by 10-20% and you are done.

[Lutkeveld]

@AleksaNS what do you mean 'without some special gain'? Creating a bass bump is better done with an overtuned port, shrinking the volume will give a bump in the higher (90-100hz) frequency.

 

Okay, ran it trough the simulator. The recommended enclosure is way too small and overtuned.

Which dimensions are your maximum? I'd recommend going with a single closed 50 liter cabinet and let room gain do the work.

Going above 100-150 watts will cause the driver to exceed the linear excursion limit.

 

You can go ported: it will have somewhat deeper bass but will be bigger and need a highpass filter. I'd recommend not going this route.

[Guest]

@AleksaNS what do you mean 'without some special gain'? Creating a bass bump is better done with an overtuned port, shrinking the volume will give a bump in the higher (90-100hz) frequency.

 

Okay, ran it trough the simulator. The recommended enclosure is way too small and overtuned.

Which dimensions are your maximum? I'd recommend going with a single closed 50 liter cabinet and let room gain do the work.

Going above 100-150 watts will cause the driver to exceed the linear excursion limit.

 

You can go ported: it will have somewhat deeper bass but will be bigger and need a highpass filter. I'd recommend not going this route.

I want to say that if he wont listen it loud whole time while driving that car than there is no need for gain at <50Hz... 

[Lutkeveld]

I want to say that if he wont listen it loud whole time while driving that car than there is no need for gain at <50Hz... 

 

No, he won't need all the power all the time, but even at low listening levels deep bass is nice to have.

Pretty sure a sub is meant for way more than only 50hz and above. 

As said: I'd recommend going 50l sealed with 100-150 watt. With room gain it will be linear to around 25hz, nice and low.

[Guest]

No, he won't need all the power all the time, but even at low listening levels deep bass is nice to have.

Pretty sure a sub is meant for way more than only 50hz and above. 

As said: I'd recommend going 50l sealed with 100-150 watt. With room gain it will be linear to around 25hz, nice and low.

Its nice to have but i think that on normal listening levels he wont notice it... But that's just mine opinion. I think you are generally right and he should listen to you

[Lutkeveld]

@AleksaNS

Maybe not, but it's possible so why not. Do you know the equal loudness contour? It generally says that you need a decent amount of SPL to pick up on bass frequencies. 

Combined with the masking caused by road noise, you won't notice the deep bass on background listening levels. But due too the huge room gain in cars you will have nice deep bass on normal listening levels, even when the normal -3db is at 37hz (still pretty low).

[princedylan101]

Sooooo I am just dropping my two cents in and in my car i have:
 

Subs: Dual kicker 600 rms, 1200 max
http://www.bestbuy.com/site/kicker-dcomps12-dual-12-single-voice-coil-2-ohm-subwoofers-with-enclosure/7752051.p?id=1218859509029&skuId=7752051
Amp: 1200w amp, 600 rms

http://www.bestbuy.com/site/kicker-cx-series-1200w-class-d-mono-amplifier-with-variable-low-pass-crossover/7706044.p?id=1218858583396&skuId=7706044

 

I didn't change anything in the car except I got a newer battery (optima yellow top), and I think 2 more grounds were added to the battery itself. I have 2 amps in my car, the second powers the door speakers so in total mine should be around what you want to pull, and I am in a zx3. So I wouldn't worry too much about it just make sure the amp is a good known brand and that you use the proper wire gauge.

[ohJey]

Sooooo I am just dropping my two cents in and in my car i have:

 

Subs: Dual kicker 600 rms, 1200 max

http://www.bestbuy.com/site/kicker-dcomps12-dual-12-single-voice-coil-2-ohm-subwoofers-with-enclosure/7752051.p?id=1218859509029&skuId=7752051

Amp: 1200w amp, 600 rms

http://www.bestbuy.com/site/kicker-cx-series-1200w-class-d-mono-amplifier-with-variable-low-pass-crossover/7706044.p?id=1218858583396&skuId=7706044

 

I didn't change anything in the car except I got a newer battery (optima yellow top), and I think 2 more grounds were added to the battery itself. I have 2 amps in my car, the second powers the door speakers so in total mine should be around what you want to pull, and I am in a zx3. So I wouldn't worry too much about it just make sure the amp is a good known brand and that you use the proper wire gauge.

What car do you have might I ask?  Upgraded alternator or stock?

[princedylan101]

What car do you have might I ask?  Upgraded alternator or stock?

I drive a ford focus zx3, and I haven't made any alternator changes.

[ohJey]

I drive a ford focus zx3, and I haven't made any alternator changes.

20 more amps than mine hmm

[ohJey]

20 more amps than mine hmm

 

I drive a ford focus zx3, and I haven't made any alternator changes.

It should be fine though becasue you're using 1200 watts and I'm using 800.  33% change in sub power vs ~20% alternator

[Sintezza]

i would put those 2 subs on two 650W rms mono blocks.

maybe 750W rms. but not much more then that.

you also gonne need a decent frequancy filter, and you have to build a enclosure with enough liters for bothe woofers.

 

i would personaly not recommend to pick a multi channel stereo amp.

even if you could bridge the output channels, it will allways be a pain in the ass to get it fine tuned.

 

But do you realy need 2 of those subs?