New sound system - advice :)

Neuroticus

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Jul 28, 2007
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Hello!

My first post, as of today I am the proud owner of a 03 (53 reg) Fiat Punto 1.3TD Active :) However I need to kit a new sound system into my car and have never done this before.

I know the basics - headunit amp speakers and sub if wanted.

To start I just want to get a head unit tomorrow which has a line in for my creative zen. I am looking at this headunit:
http://www.sony.co.uk/view/ShowProd...verview&imageType=Main&category=ICA+CD+Tuners

Now, reading the manual/specs I see it has a built in amp and also RCA connections for pre-amp outputs to which it has 2x outputs (Front L&R and Rear L&R), which is good because to start I want to use factory speakers, and at some point will want to upgrade speakers and probably use an amp.

Now my confusion - all the outputs are RCA - how do i convert that connection to a speaker connection to use the build in HS amp and play sound through factory speakers.

Ok I also notice it has an output for a sub. Looking at the manual/diagram it goes HS -----> Sub via RCA lead. It says on the manual the sub is an active sub (i assume this means built in amp). Now if i were to one day get a sub and speakers, I wouldnt want to use an active sub (I like to pick all the companants not have things built in) so could I connect an amp to this sub output and plug a sub into an amp?

My last question - when I get new speakers, and a new sub, and an amp, would I need 2 amps? One for the speakers and one for the sub? I dont want to spend a bomb on this, just a suituble setup. Or would it be better to get a mono amp for sub and use the HC amp for the speakers? I know an external amp would be louder - volume isnt my aim - I want a fairly good, not TOOO expensive setup. Is it even worth getting a sub? Or are there speakers which can pump enough bass for most music without having the car turning heads as a nightclub drives down the road.

Help would be appreciated!

Thanks guys :)

Harry


EDIT: When I come to get speakers (will be soon) what size do I need? I want to replace all the speakers, and what are the advantages of using 6x9s on the parcel shelf as apposed to using normal speakers in the rear doors like factory?

Thanks
 
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Neuroticus

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Well I want to start with just a head unit - its all I can afford and it will allow me to play my music from my zen as I dont have any tapes.

Im thinking £100-120 on the head unit.

As for the rest I would budget maybe £250 more for speaker upgrades/amp.

I know im a bit tight, im not looking for a **** off fancy system just something which will deliver fair sound and allow my zen to play too :)

Cheers mate
 
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Neuroticus

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Ok I have cleared up a few of the noob questions I asked.

I dont need to convert the RCA connections lol - they are PRE AMP duuuh.

I assume the sub output goes into an amp, then a sub? Please let me know if that is right.

Now the real question:
If I get a 4 channel amp, can I power two front speakers AND a sub, then wire the back speakers into the HU. If I do this, I assume I wire the 2 RCA connections (red and white RCA for front speakers, and red and white RCA for the sub) into the 4 channel amp. THEN I wire the 2 front speakers into the amp, and the sub into the amp. How would this work with only 1 sub since the HU outputs an L and R signal, how do I change this into mono mixing L and R?

My last question: will there be problems with the different power ratings with the speakers and sub if I use just 1 amp for all of them? Eg the sub might be 100W and the speakers might be 20W but the sub might be i dunno... 400W?

Thanks guys!
 

BenW

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Most 4 channel amps will be able to power a sub by 'bridging' two channels into one. So you would have a front left on one channel, front right on another and the sub on the remaining two. Then rear speakers can be connected to the HU although you may want to try without rear speakers at all as it gives a more hifi sound (from the front of the car).

You take an RCA from front out on the HU to one input on the amp then another rca from sub output on the HU to the other input on the amp. Connect front speakers to channels A/B and then sub over channels C/D (manual will say how to do this). As you will be using one terminal from C and one from D the red and white inputs are automatically combined to give the mono signal.

Looks like you got a little confused on the last question, if you meant the amp was 100W RMS (not peak) then thats going to be a bit too low if the sub is 600W RMS. Ideally the RMS figures of the speakers should roughly equal that of the amp or if money is available the amp should be MORE powerful so its not stressed.

So, if you had an amp that does 100W x 4 at 4 ohms then you could have

2 front speakers at 100W each or less
1 sub at roughly 250W each (This figure depends on the amp but normally a bit over double as two outputs are used)

However having a speaker capable of a higher wattage being powered by a smaller amp will work, you just wont be using the full capabilities of the speaker
 
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Neuroticus

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Fantastic! Thanks for that awesome reply.

Ye i made a typo, I thought if the amp is say 400RMS, and i was running speakers which were 100W and a sub which was 300W (im just making these figures up) would there be a problem?

Im looking at this head unit currently, it has 4V preamps which should give nice sound reduced noise etc and it has 3 preamp outputs (front/rear/sub) aswell as the AUX input I want:

http://www.sonicelectronix.com/item_9100_Pioneer+DEH-P6900UB.html

Is it any good? I will look at amp/sub/speakers later I dont get my car till tomorrow so need to check the speaker size/locations and see what I want to do.

Thanks again, very well explained :)

EDIT: This is what I meant to say:

My last question: will there be problems with the different power ratings with the speakers and sub if I use just 1 amp for all of them? Eg the sub might be 100W and the speakers might be 20W but the amp might be i dunno... 400W?
 
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chaos

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My last question: will there be problems with the different power ratings with the speakers and sub if I use just 1 amp for all of them? Eg the sub might be 100W and the speakers might be 20W but the amp might be i dunno... 400W?

The only problems you may encounter is if you either show too low an impedance on the sub channel or if you substaintially under or overpower the speakers/sub.

HU seems tidy - don't set too much by the preout voltages though - it isn't the be all and end all.
 
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Neuroticus

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Well I installed the head unit - its fantastic Im considering not bothering to upgrade the speakers and just stick a sub in because it sucks at low frequencys :p

Unless I can find a tweeter which will fit in the space of the current one - anyone know any which will fit for a punto MK2b? The speaker is TINY! Didnt remove the cover to check real size not sure how to do that without breaking it :(
 
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