What does an amp do?

[Wayne]

I need to buy myself an amp (im told) because ive just bought a sub woofer. I have 4 speakers overall, 2 standards ones in the front and 2 6x9's in the parcel shelf.

I was going to buy myself a 5 channel amp. But why do I need one?

Does it matter if you get a cheap no named one? im actually looking at a 6 year old sony one though.

Any info would be really appreciated.

Wayne

 

[Arnold]

What power in W are the 6x9's and the sub

The headunit for example can output 4X50w or 6x50w (actually i believe its like 35rms) so if you've got 2x80w 6x9's, and you have them quite loud, the head unit cant actually cope with the amount of power your drawing out and may damage it, blow fuses or do whatever it does, so an amp is needed to be able to cope with the extra strain e.g i've got a 2x90w amp powering my 2x80w 6x9's, and another amp powering 2x50w speakers. I've also got a 1100W amp powering my two subs! Theres no way a head unit could cope with that kind of power

Also, head units are only powered up by the very thin iso adapter wires, and if the speakers run directly off this, theres no way they could cope with silly power. All amps should run directly off the battery using various thickness of power cable depending on the amps power!

Hope that helps! im sure others can provide better answers than that.. (hands microphone to pete! lol)

Arnold

 

[ricardo_swarez]

you only need a 2channel amp as your only running two things, also you get what you pay for,so you may buy an unnamed amp, that says 600watt, but this amp may give 600watt when given and imput of say 100volts.. but your car delivers 12volts, so in practise, when the amps tested, the actualy output is much less than stated, if you buy an amp from a replutable dealer, like alpine, then all there systems are based on car voltage, so the watt on the amp is the wattage you will get.

msc disclaimer- to stop people ripping my post apart
600watt and 100volts were randomly plucked figures to give the guy and idea of what im talking about.

 

[Zephyr]

lol ricardo disclaimer lol
but anyway since none had said but heres something to note
some things might say 600w(watt) amp but that could b peak watt as in if it actually ran at 600w then it would roast "but" u also get watts in "rms" which is when u can run music/noise at 600w constantly

shop around for amps with rms figures if its cheap n says high watts its prob peak watt that have rms at like 150 which is useless imo try get a good rms amp(few hundred figures dont worry bout needing to get 1 like a 1100w amp like arnold thats b 2 much as hes powering 2 subs(also he would have another amp 4 his other speakers) n on avg imo if u have 2subs u want to feed them about 1000w's)

 

[Wayne]

so if i have 4 speakers and 1 subwoofer (2 standard speakers in front, 2 sony 6x9's in parcel shelf, i think they are 200w and finally a 400w ripspeed subwoofer) what channel amp do i need and what watt should it be

 

[Arnold]

More than likely, they'l be another figure for the 6x9's, for example, mine say 300W on the box, but really they're 80w each! You need to find the RMS figure, not the pmpo or peak power

The standard fronts you can continue to wire off the head unit without amplification.

For the sub, you'l need an amp capable of 1X400w
http://www.caraudiodirect.co.uk/pro...d=2700&cadid=ae0f0617a16080cbbf4e429cc92991c3 i think would suffice

 

[Retepetsir]

Sorry I havent been around. Right.........

The subwoofer needs a seperate amplifier to run it instead of the headunit. This is due to the power draw that it imposes on the amp. The subwoofer is probably rated at around 150W RMS (see below for quick explanation, its the true power), so we can ignore the 400w max power figure. The headunit (even though it might say 4 x 50w), actually puts out nearer to 4 x 15w RMS (true power), therefore, trying to drive a 150wrms subwoofer with a 15wrms headunit wont work!

I'm not a fan of amping the 6x9's without amping the fronts, as your sitting in the front, and we listen to sound coming from in front of our ears......therefore its best to amp the front speakers. However, your situation is slightly tricky as you only have standard fronts, doh!

If you tell us your budget, we can try and work with it.

But what I would do is this:

1) Buy one 4-channel multichannel amplifier + 1 wiring kit + 10m or so of speaker wire.
2) Bridge two channels together to run the subwoofer (more power available)
3) Use the other 2 channels to run a new set of speakers in the front of the car (ideally components, which have seperate mid's and tweeters, otherwise a set of coaxials will do)
3) Run the 6x9's off of the headunits rear speaker outputs
4) Fade the 6x9's out slightly, so the majority of the sound is coming from in front of you.

A couple of pointers:

- You need to be looking at RMS figures (Root Mean Square) of voltage, not maximum/peak/pmpo/etc ratings. Ideally the amp should deliver the rated RMS value of the speaker it is driving, or be slightly over this value.

e.g. The subwoofer might be 400W max power, but 150W RMS, so look for an amplifier that can give you around 150-200W RMS of power

Now to explain why I've suggested the above setup.....

For the price of a decent 5-channel amp, you can get a 4-channel amp, plus the extra speaker cable, plus a pair of speakers for the front of the car. This setup should benefit you a lot more.

All I really need to know is your maximum budget, then I'll try and suggest a couple of things

Cheers

 

[NeX]

depends on what you want to amp, all of it or just the sub?

the sub will need amping because it is so big that the HU amps don't have much of an effect.

but you could amp the 6X9s as well to make the whole system more noisey.

don't amp the front speakers because they probably won't hack it.

if you just boost the sub then a mono channel amp is fine but if you want to amp the 6X9s as well then you can get a two channel amp and bridge the sub

 

[Wayne]

Well i think it would be a good idea to buy some front speakers.

My budget is as cheap as possible, but don't mind paying a bit extra for quality. So probably about £60 for speakers, amp and wiring.

I would like to amp the front speakers (new ones) and the sub. I will leave the 6x9's alone.

 

[NeX]

ohhh £60 buck aint much mate,

i paid £500 for my whole system and the pro's will tell you it aint great.

£50 mutant 2 channel amp
£12 autoleads wire kit
£20 sony front speakers 13cm (i think)

total £82, i don't think you'll get cheaper than that...

 

[Arnold]

This amp on ebay would be more than capable of powering the 6x9's or the fronts. I've got two of these fitted in my car.. one powering the fronts and one powering the rears. Its on ebay for a quid, and has wires with it too!

http://cgi.ebay.co.uk/Alpine-MRP-T1...ryZ18796QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

There's also a second one on there. Search for MRP-T130

 

[Wayne]

would these be ok to power the sub?

 

[Arnold]

How powerful is your sub tho! that amp i believe can power a 250W rms sub, however i use them both for my 6x9's and 13cm fronts

 

[Wayne]

All i know is that it said 400w, i got it second hand off eBay and came with no other info.

 

[Retepetsir]

I'd still go with a 4-channel amplifier. Then bridge 2 channels to run the sub, and use the other 2 to run some new front speakers......

You'll need around £200-£220 for the lot tho..........!

 

[andrewb150]

You either need to buy a monoblock 1 channel amp for your subwoofer or a bridgable 2 channel stereo amp. However if your headunit does not have a dedicated subwoofer out you will need to buy a amp with a variable crossover frequency. Otherwise your subwoofer will be trying to output to wide a frequency range and sound distorted.

I imagine that your radio is powerfull enough for your 4 stereo speakers and that you have a dedicated subwoofer out. So if your on a real budget go for a cheap 222W sony 2 channel bridgable amp from www.caraudiocentre.co.uk for like £40. (This would be for the sub)

For £60 I think you are going to struggle to get new front speakers and a 4 channel amp for them, aswell as a sub amp.

Unless you already have some long stereo phono leads and some nice gauge wire to power the amp you will need a wiring kit aswell

I depends really how loud you want to be able to play your music... or how deaf are you and your friends are!!


I think the priority should be:

Amp for subwoofer £40
Wiring kit £15

You can get Replacement front speakers (17cm) for like £25 min but that wont fit in your budget.