druddle

i have the girly clio with 6 speakers in it. i have been told that i can split the rear speaker wires and take one connection to the standard speakers and one to an amp.

is this safe ?? will this not overwork the head unit ?

steve McCulloch

I'm no expert at all here - but I did ask the same question a few years ago. A few stereo places laughed a long time at me.

Something about you get sheds loads of static interference.... so dont even bother..... Best to get a cheap after market stereo with a couple of preouts... (and not Panasonic as they are crap - IMHO)..

I'm sure someone else will comment.. but this budget attempt is poor quality

druddle

only problem is, the cd changer and remote for the renault unit are not compatible with the kenwood i was gonna buy, so i will have to replace the lot.

i was just looking to try and save some money. maybe i should upgrade the door and rear speakers (8" i think). any recommendations anyone ??

rockin'Ru

If the amp has speaker level inputs built into it,yes,you could run it this way.If you'll be running a sub from this amp,it won't sound TOO bad,but I wouldn't run any of the other speakers in the car that way.As mentioned by Steve,it's not the cleanest sound you'll ever hear,but for a sub,I've seen it work with acceptable results.

john banks

Agree with above. I wouldn't grace a really good car with this sort of install, but have done similar on our second car a Peugeot 406. Also factory remote, HU, CD changer with factory display. Big incentive not to change when just doing a budget job.

Tried speaker level inputs to amp, but horrendous alternator whine. Now, a Maplin line level converter isolates it electrically at the back of the headunit and goes to an RCA lead to the amp in the traditional way. A power supply filter in the factory headunit got rid of the last bits of noise. Then there are new components in the front and 6x9 in the back shelf all running off an amp, with more power to the fronts than the back which provide fill and LF extension.

Factory headunits seem inherently noisy and of relatively poor frequency response and detail when amped. Agree that for a sub it could sound better. If you change the speakers, it is usually easier to put better quality versions in of the same size. If you stay on factory speakers and add a sub, you may find a "gap" between the top roll off freq of the sub and the bottom of the front speakers between say 80 and 150Hz (which doesn't sound much but remember that this is almost ONE OCTAVE). Move the top of the sub range higher and it takes over and you can easily pinpoint the source. In a good install, all the sound should appear to come from in front of you - difficult to pretend if you can hear a sub pounding from the boot.

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john banks

Oh, sorry another thing. If you use the rear speaker wires for amp input, you could easily overload the headunit. Most headunit are already bridged and 4 ohms is as low as they go impedance wise. The input impedance of a speaker level stage or line level converter is likely to be also around 4 ohms to allow maximum power transfer. Therefore you COULD be running the headunit at 2 ohms so it could suffer and go ping. So really I would say either amp inputs or speakers and not both from the same headunit speaker output - which then means you need to find another pair of amp channels to run the rear speakers - grrr.

Another thought that I had once was to try and take a "clean" line level output direct from the CD changer to the amp, but unfortunately my factory CD changer was not connected via phono leads, and I haven't yet found out the spec of the output or the impedance. I suspect most factory CD changers would be similarly esoteric. Just a thought as it would avoid the pre and "power" amps of the headunit - but of course you would not be able to use it for tape or radio, and you would have no control over the volume from the headunit, so probably quite a stupid idea after all!

druddle

my main point of concern is exactly what john has said - the amp in the head unit going ping as i am running 2 ohms on it. am not sure though as it has 4 speakers i assume running off the front (tweeters and door 8") which i found by playing with the fade and balance earlier. then i assume it has the 2 rear speakers running of the rear amp channel. from what i can tell they are the same 8" speakers.

now i know that does not mean that you can definitely put 4 speakers on the rear channel without overloading the impedance, as there are no technical specs to go from. it is probably a dangerous assumption to make.

i may give it a go and see what it sounds like.

as for swapping the standard door fit speakers, any recommendations ??? i assume anything will be better than the cr@p fitted as standard !!

thanks guys !

dave

[This message has been edited by druddle (edited 07 August 2001).]

john banks

CAUTION! The key point is that the tweeter on the front channel does not significantly lower the impedance seen by the headunit - the headunit will still see approximately 4 ohms. This is because there will be a capacitor in line with the tweeter which will give a 6dB/oct high pass filter at somewhere between 3.5 and 5KHz. Below this the amp will only really see the impedance of the woofer (it's obviously a gradual roll off not a sharp cut so I am talking generally). Above this it will see both, but there is only a small fraction of power dissipation above 4KHz (c.10% total) so it doesn't matter that they are in parallel above 4KHz. This is a completely different kettle of fish to using a full range unknown impedance speaker level input.

8" does sound like a funny size for such a small car?? If they are really that big, then you could get some very nice bass from just replacing those. You might be quite surprised - I was pleasantly suprised by the authority of a pair of 6x9s in the above Pug install. Another thought is that there is certainly no harm in buying a suitable amp and seeing what the whole thing sounds like (running HU only at 4 ohm as discussed). You then have the option if you are not happy of upgrading the rest of the kit. After tweaking the Pug install I am reasonably happy with it given the cars overall use (wife/long distance cruiser). If this is your pride and joy and you like your tunes, I suspect whatever budget you have will have to treble to replace all the OEM stuff. Sorry.

[This message has been edited by john banks (edited 07 August 2001).]

druddle

oops spot the dumbass. they are 6" units not 8". doh !!!

i just want some more low end really. if i can get a satisfactory amount from putting replacement 6" units in then i will do that.

but i used to have a honda with a pioneer in and theres nothing like having your head throb with a ffaatt bassline !!

dave

john banks

I wonder if it is 6 or 6.5"? If you can get 6.5 in then they have 17% greater cone area which gives better low frequency extension which is useul whether you have a sub or not. I was quite surprised how low Infinity components go, but they do need lots of power. Options 655CS 6", 605CS 6.5" - see