buying help needed ASAP!

[elgan]

right, christmas is coming, and im seeing loads of deals and things in the mags


im going to buy myself an ice system for x-mas.

ive got a 3dr astra mk3 at present running standard vauxhall ice.

i know sweet f.a. about ICE except for it makes a noise and that my standard stuff is ****e.

what i have in mind is a headunit + cd changer
6x9's
front speakers with new tweeters cos the old ones dont work
2x 12" subs
amp

ill do my own build so i dont want sub boxes etc

from reading the adverts i see there are various sizes of subs and different watts. i assume the higher the watts the better, but then what kind of amps are required?


id probably buy the whole lot as a package, but ive got no idea what makes etc to look at and prices to pay.



any help, recommendations, etc much appreciated


thanxs in advance



elgan

[Dexy]

be carefull buying amps and subs because you dont wanna go and buy an amp thats gonna kick s**t into your subs get an amp thats half the wattage of the subs

[elgan]

so, if i get 2x12" subs at 600w each

get a 600w amp?

[DaveB]

basically, if u see a 600watt amp for £100, it means its about 50watts.,

Only believe output figures when ur getting to the good brands
ie.

kenwood,
alpine
kicker
RF
infinity

etc etc

If your amp is 600watts, and a 2channel, then you will have 300watts going through each sub. Which is safe, if your amp is 300watts(providing this is a decent make of course!) and your subs are say, 150RMS, that is the boundary for damaging equipment.

[d0gz_bollox]

I run a 450w sony 10" sub(low pass) and 2 240w pioneer comps (high pass) of a 1000w amp and they work fine with no damage to the speakers (500w going through amp - 250w through each component). The amp is legacy.

[Neosophist]

I've got 2 x 12" Kicker subs in an MDF bass box i built myself which takes up all of the MK1 boot, it's running an XS 300watt amp (2 x 150watts or 1 x 300 watt) basically it means you get 300 watts if you bridge it, use one off the right speaker and one off the left speaker to get double the watts, i find with my 300 watt amp i can still overdrive my kicker subs (400watt max power) so i use a 150 watt for each sub, the amp has the cross over set to lpf (low pass filter) which means the subs only get the bassier frequencys, and it kicks ass, when i crank it up the whole car vibrates really badly and your legs shake when you get out, amps are very important, most have a gain on them, set this to minimum when you start, crank up the hu to you required kick ass level and then adjust the gain on the loudest song you can find till the subs don't "pop" then fart about with the other settings, till you find it ok. www.caraudiodirect.com have lots of good stuff, uk based firm, also bass junkies in wolverhampton. If your' bulinding your own box use MDF (wear a mask the dust is cancerous) you can get away with 18mm chip board but you might here the vibrations, my box is just a box that takes up the whole boot, with two holes for the subs then two smaller holes each end for the air to come out (the subs push a lot of air) when you build the box put it in the boot. i've also seen people use the yellow pipe (gas main pipe) which will hold two 12"' at each end perfect.

My box looks like this

___________________
|O O |
| OO OO |
| OO OO |
|O O |
------------------------------

The four corner holes let the air out (bass) and the two in the middle are for each sub resting on top of the box, with the back of the sub immearsed, make sure the box fits well and is air tight apart from the holes as leakage of air reduces base, after having mine cut to match perfect and screwing it togeather i ran silicone sealent in around the joins to make sure no air escaped and now it kicks.

Hope this helped a bit

Martin

[elgan]

i dont understand any of this bridging lark

i was told to get a 4 chanel amp and bridge it into 2??????

wot does that mean?

cheers for the help so far


elgan

[Chameleon]

Bridging is pretty simple. All it means is that you are joining pairs of channels together to make fewer, bigger channels. If you have, say a 4 X 100W bridgable amp you can bridge it into 2X 200W. This is done by connecting the + from one channel and the - from the other to the speaker. (You usually need to flick a wee switch too.)

To be honest there aint no point in having a 4 channel amp just to bridge it into 2. You would just be better buying a more powerful 2 channeler to start with. Or if you do, you could run a pair of stereo speakers (fronts or rear 6X9's for example.) from 2 channels and bridge the other two to run the subs, making it a 3 channel amp.

On a related note, speaker impedance is also important. Car speakers are usually 4 ohm. If you think of an ohm as the amount of power a speaker will let through, like water through a pipe, then two speakers in serire (one after the other in the same circuit) is DOUBLE the resistance. So the amp will have to work harder to squeeze the power through. BUT, if you wire them in parrallel then the resistance is HALVED (twice as much wire/coils available.) Therefore the amp can make more noise as it isn't working as hard.

Of course there is a cost in this as the lower the resistance means the amp will draw a lot more current! Therefore it is only really advisable to try this with a good quality amp that'll go down to 2 ohm.

Amp power= 2X100w through two channels, one speaker@4ohm on each.
Amp power =200w through one channel bridged from the previous two, through one speaker @4ohm.
Amp power =100w through a bridged channel through two speakers in series@8ohm.
Amp power =400w through a bridged channel through two speakers in parrallel@2ohm.

I expect this will be as clear as mud but thats about as simple as it gets.

Next question!

[elgan]

ye. its makes some sense,

i think ill go along to some audio shops look around and see whats going taking into account the info ive had here

cheers

[Neosophist]

Oh yeah i forgot to mention, don't leave the amp on when the cars not running or you'll soon find yourself with a flat battery, as for wiring an amp up, the speakers are obvious, but you usually have 3 power points, +12v, RMT and Ground

The +12V can be run straight to the battery as most amps have their own fuse, the same with the ground, the RMT or remote is a +12v as well but is usually connected via a switch so you can turn the voltage on and off so you don't leave the amp on, most modern stereos output a 12v remote, mines a blue wire, but if not connect it to either a switch or an ignition live, so you don't forget to turn the amp off.

+12v -------- RMT ---------- GND
| | |
Battery + Switch Battery -
|
Battery

the switch being an spst ie two pins that are either closed or open, one wire goes to the battery the other to the remote on the sub, so when the switch is flicked on "boom boom boom" and when off, no music, that might be handy if you havn't got a wire on your stereo to do it or don't wanna use an ignition live, ie: turn the sub on without the ignition, usually find for up to 30mins without draiing to much battery.

Martin

[Neosophist]

damn my drawings never come out right.

no attachements either, if you wanna pic of how to wire it just ask if you get stuck.,

[mtrayer]

You're all talking a load of old c***p none of you understand the difference between RMS output and PMPO. Dogz ****** thinks he gets 1000watts out of his Legacy you'll find that the actual output RMS output is only around 500watts, sorry that the way it is. i also noticed that neosophist is taking balls as well each specific sub requires the correct size box and bass port to work properley you can't just cut out holes as you feel free. Do some research lads and stop trying to tell other people what to do when you don't know yourself.

[d0gz_bollox]

hence the fact I say 1000 max. max being the comanly used way to define the maximum wattage an amp can pump out for a fraction of time before going pop.