Adding Power to speakers

[Pav]

I have installed 4x50W speakers in my VT, along with a head unit rated for 200W total. Now I know the power from the h/u is sufficient but would it be worth wiring in an amplifier to the h/u? Will it improve quality or what? Would it have to be a 200W one or will it combine the power from the h/u so that I can get like a 70W one to a add a bit of power?
I already searched google but wasn't sure what to search for...
Thanks.

[Joe Peeps]

It doesnt work like that In the car audio world, the figure to look for is the average power, commonly referred to as RMS - root mean square. It is the measure of continuous power that a particular unit is capable of producing/handling, and is far more meaningful then max power figures which tell you very little. (RMS is still measured under certain conditions so also remember it is not the be all and end all)

Your HU may be rated at 4x50, but in reality this equates to around 15-20RMS. Sufficient, yes, ideal, no. By adding an amplifier, what you are really doing is bypassing the internal amplifier in the HU (for the channels you are running amped naturally) and sending the signal via RCA's to an outboard power supply (your amp) This is why they are called "pre" outs - pre amplification, that is if your HU has any. This will definitely go to improving quality. So to answer your question it doesnt add to the HU figures, but substitutes.

You mention you have installed 4x50watt speakers. Is this an RMS figure, or peak(same as max)? If its peak, you will still benefit from adding an amp but its probably not worth it IMO, depending on your expectation and available funds.

If you tell us what model speakers you installed and what HU you have we can give you more accurate advice

[shaggerz]

that is a horrible horrible question lol

1. your head unit is not even close to 200 watts. The most you will realistically get is about 14 watts per channel. This is a limitation of simple physics and can be explained in detail if you like.

2. amps do not "combine" output power, the input signal is only used to tell the output stage what its doing, and all the power is supplied in the output stage.

3. lets say for a minute that you actually had 200 watts available. Adding an extra 70 watts would make absolutely bugger all difference to the sound. Just remember this simple rule. To make the sound twice as loud, you have to multiply the power by 10. So look at it this way... a 200 watt amp is only twice as loud as a 20 watt amp. 70 watts is nothing in the scheme of things.

4. with the above points in mind, a 70 watt amp would be a fair improvement on a 14 watt one, but there will be little to no increase in audio quality. The only thing that more output power does is allow you to go louder before the output clips and you get horrible horrible distortion and burn out your speakers. IF at the moment, you never turn it up loud enough to distort, then you do not need an amp at all!!

[Joe Peeps]

4. with the above points in mind, a 70 watt amp would be a fair improvement on a 14 watt one, but there will be little to no increase in audio quality. The only thing that more output power does is allow you to go louder before the output clips and you get horrible horrible distortion and burn out your speakers. IF at the moment, you never turn it up loud enough to distort, then you do not need an amp at all!!

an amp is not just good for extra power over a HU, and can offer noticeable improvements in sound quality, particularly further up the cost scale, but from the looks of this particular situation i understand exactly your point Shaggerz

[garfa]

shaggers, not right exactly. an amp will have a better damping figure (larger better.) than the internal mos-fets of the h/u. now pretty much the damping figure relates to how firmly the amp moves the cone. this will give the speakers more 'punch', thus an impovement in SQ.
also you sort of shot yourself in the foot, the ~20Wrms from the h/u is only a third of the figure that most speakers that get talked about, in general, so really it is more the increased damping figure over the extra few dBs you gain over using an amp.
ALWAYS get an amp if you think your speakers could sound better. its up to you to how much you value your sound.

[shaggerz]

now you're splitting hairs I was speaking assuming a particular end of the cost scale

[Pav]

Well first of all I assumed that the speaker's (Fusion Encounter 6.5" 3-way) RMS value was around 50W because the stated maximum wattage is 200W per speaker.
It is stated on the head unit that it is rated for 4x50W RMS I think. It's a sound4 head unit that I got for cheap.
I understand what you guys mean about the pre-outs, thats what I didn't get before.
The sound does distort when I crank it, so hopefully an amp will allow more volume increase, say a 500W amp? (Price doesn't matter, its second hand)

[garfa]

yeah not trying to show anyone up or stuff like that.
just can't stand it when people talk about volume all the time. :-)
also pav the h/u will be 4x50W max. sound 4 is not going to produce a unit capable of that sort of power. in addition you need a 4x50Wrms amp, 500W does not mean anything.

[Pav]

Ok I think I get ya, i need to match the RMS from the speakers to the amp otherwise it will damage the speaker, right? I'll buy a 4x50W RMS amp because of the damping factor and also my new head unit will be 4x45W RMS so I will need an amp to run the speakers anyway. Thanks for clearing that up.

[SweetWagon]

Ok I think I get ya, i need to match the RMS from the speakers to the amp otherwise it will damage the speaker, right? I'll buy a 4x50W RMS amp because of the damping factor and also my new head unit will be 4x45W RMS so I will need an amp to run the speakers anyway. Thanks for clearing that up.

essentially yes, you need to match the rms rating of the speaker to the rating of the amp. dont buy a crap amp either, if your on a budget, get a response (jaycar) 50wx4

[hakhawk]

does anyone actually make a headunit that is around 45-50wrms?

all the units ive seen, have a 4x45w or 4x50w figure written on them, but it is always a max figure.

what brand and model is the new headunit you're getting mate?

[SweetWagon]

does anyone actually make a headunit that is around 45-50wrms?

all the units ive seen, have a 4x45w or 4x50w figure written on them, but it is always a max figure.

what brand and model is the new headunit you're getting mate?

dont think so... if you think about how large a 50wx4 amp is, i cant see how they can cram that into a little headunit... possibly an exotic brand like nakamichi may make something that powerful but im not sure.

[garfa]

nah nak dont make any 4x50s in the curnet line up. besides if your running a nak unit you would probbaly want more than 50w per channel for headroom and what not. nak have a seperate psu, just to keep the power in clean.
pav, you are missing the point. music is not like power. the frequency is always changing and amplitude. the rms of an amp is measured by using a test tone (const. A and F) and from this we can use as a reference point.
now you will have probbaly noticed that a power figure will going something like:
400Wrmsx1@14.4V = 1%THD+N 20-20kHz.
so pretty much its just what it says X power @ X voltage with X distorsion between X frequency range.
where as the amp's maxiumu wattage will not be tested under certain conditions. they will not state the distorsion or if the amp can continously maintain that level of power. instead they will have just played a huge tone into the amp making it clip for the biggest power figure while taking the spike of the wave instead of the average.
with me?

[stocky]

dont think so... if you think about how large a 50wx4 amp is, i cant see how they can cram that into a little headunit... possibly an exotic brand like nakamichi may make something that powerful but im not sure.

i dont see why they cant fit some of that technology into the double DIN headunits at least. maybe its a heat issue

[calais_cruzin]

Would have to be a heat issue, most good h/u have a fan on em atm for 16-18rms, soo for it to be puttin out 50rms she would have to be a fair size for it to be able to stay cool in such a enclosed environment.

Ive seen sum very tiny amps, but nothing that would fit in a DIN slot or DDIN and have the H/U too n still not overheat.

My Alpine h/u has a lil fan, she gets preety hot, soo i cant see a tru 4X50rms h/u comin out.

Unless they make one that u had to Cut a hole in ur piping for A/C vents to shove the ars of the H/U in there to stay cool hahah as if

[Pav]

Yeah, i just checked, it does say 4x50W max, anyway... would this amp be worth getting for the speakers tho?
http://www.jaycar.com.au/productView...=&SUBCATID=595

[garfa]

yes, perfect.