jase555

Hi Guys,

wonder if anyone can help (IN IDIOTS TERMS)

what does an amp do, have a good sound system in car ie Head unit and speakers, what benefit would an amp be/do.

Also what is good, don't have a lot of money and need boot space for junior's buggy

thanks in advance

Jase

gregh

It amplifies the sound, from what I've been told it makes a huge difference to any head unit & speaker. I was told it was better to spend £100 on speakers and £100 on amp rather then get £200 speakers on their own.

I've just been advised to order a Philips DAP 6040, cost £139.99 from

john banks

An amp is a box that connects to your headunit and amplifies the signal much more than your headunit ever could much more cleanly. It does this by using a nice big power supply to step up from 12V, and then using high specification circuits that are too expensive/big/heat producing to fit in the confines of a small headunit.

Headunits will quote 4x45W but are actually about 1/4 of that in terms of clean power. Most amps produce at least 5-10 times that power with much lower distortion which gives you effortless crisp sound and a whole new world of powerful bass, bringing quality aftermarket speakers to life. It is like the difference between having a turbo and not.

They are usually fitted in your boot, and need a thick high power cable connected down the left side of the car to the battery directly with an in-line fuse. A ground cable connected to the body in the boot completes the power supply. A phono cable like on your domestic hi-fi connects the headunit to the amp - typically running down the centre console to the boot to avoid picking up interference from the power leads. The speaker leads then go from the amplifier back to your speakers - it is beneficial to run new wire all the way for this - ie from the boot through the centre console or right side of the car to the front speakers. If you want you can also amplify the back speakers (I don't bother - it sounds worse) or a subwoofer in the boot which isn't as over the top as it sounds and gives you up to 1-2 octaves of extra bass extension - ie down to 30-40Hz instead of down to 80Hz like most front speakers manage comfortably. This is the sort of bass you feel and adds huge atmosphere to your music. It is also the bit that requires big power as much air has to be moved by a larger speaker cone, and is also the area which can be difficult to get right in a car environment with all the tyre/engine/wind noise etc etc. If you are very limited on boot space, small sub boxes are available, and some have fitted them to the spare wheel well or the rear deck. Some fit big speakers to the rear deck instead. You could have your amp fitted upright against a back seat or in a corner of the boot - just don't hang it upside down or put it under carpet or it will overheat. It needs to be fixed well as you don't want a missile in a crash.

See other recent posts for amp discussions - good brands are debated there - you really do get what you pay for, and I would say £120 should probably be an absolute minimum unless second hand. Also budget £25-250 for wiring kit/soundproofing of doors/trunk etc depending on how much you want to do. If you put big power to your speakers panels will vibrate and even a small amount spent on soundproofing for the front doors in particular will help immensely.

Edited to say hopefully this is appropriate "idiot" wise but not too patronising. If you are near Fife, email me and come and hear my setup and you'll see/hear what I mean, and I'll help you fit it if you want.

[This message has been edited by john banks (edited 05 July 2001).]

jase555

Thanks guys keep it coming, I do not want to put in a sub. Looking at 2 or 4 channel, thus If I don't want a sub does this mean a 2 channel will be enough

Jase

john banks

What speakers do you have fitted already - also see my edit to previous post - are you in this area? Email me offline if prefer.

Can at least help you get the amp wiring kit in as that is the tricky part but ten times quicker if you've done it before.

jase555

have put in VDO dayton's at moment as that all I could afford after getting my Kenwood MD / Boot changer setup

Jase

john banks

Well, you could use a 2 channel amp to power 4 speakers, but you lose the ability to fade. I fixed this in one install with a 1ohm resistor in series with the rears to shut them up a bit. It would be tempting to change the fronts to something nice and them amp them hard with a 2 channel amp and run the rear speakers off the headunit. A 4 channel amp would let you amp the rear speakers/allow flexibility for future upgrading/allow you to bridge to 2 channels to get big power for the fronts which can sound ace. If space is at a premium and you know you are not going to upgrade go for a 2 channel effort and if fitted vertically somewhere in the boot will take up hardly any room at all.