Audio Questions....

[jcooke]

Hey boys and girls,

I've got the premium audio system, but with a JL 12" W3D4 Sub, Alpine MRV-F345 Amp and alpine 6" splits with tweeters in the front. The amp is running the sub at 8ohms as it's not 2ohm stable (sub is dual 4ohm, so 2ohm or 8ohm), and running the front splits. The rear standard speakers are still powerred from premium head deck.

The problem is that I think the sound is pretty average. I just have a couple questions on how it is setup.

- It looks as though the amp is getting its signal from the front speakers, shouldn't it be getting them from the rears?

- The sub is currently facing the rear of the car. Would I get better sound/bass if it were facing the front

- Sound qiuality - the amp has a line level input, am I better off getting a line driver (this LC6 keep reading about) or should I bite the bullet and put in a standalone head deck. Or, is the alpine vhub really worth the dosh?

- Would it sound that much better if I had a separate amp to run the subs at 2ohm, and thus freeing up the 2 channels to amp the rears (after replacing them with a 6.5" or 5x7).

Thanks

Edited 08/02/08 01:16 PM by jcooke

[Superdan]

WHOA WHOA WHOA!!!! one question at a time please people!!!

Yes, you there sir...!?

all jokes aside; got one question to start us off... did you put all this gear in yourself? or was it in the car already? quoting the model #'s I'm thinking it was in there already?

realistically, the only advice I can offer is in regards to the 'bass cadets' in the boot.

is the sub in a moveable box? best way is to give it a couple of days of driving on each different setup as each different sub/box/amp/placement combo will give different results for different people.

I have two kenwood 12"s runnig off an 750-ish-watt Pioneer amp, with the feed coming from the rear factory speakers. the box was made over half a carton with no dimensions or capacity in mind. it was simply a friday arvo f*ck-around and turned out well!

the first position I tried it in was the box resting at the rear of the boot, with the subs traditionally mounted (external facing cones), facing the front of the car. this worked well until I built what my mates call 'The Friday Box'! this box is an extremely small box, with the same two subs inward facing (drivers facing arse out). the box sits on the small shelf in the boot just behind the rear seats. this current setup kicks the sh*t out of the subs when required and just a nice punch when necessary.

post some pics up of your system too mate, will help the diagnostics for sure!!!!

Edited 08/02/08 02:48 PM by Superdan

[jcooke]

cheers for the reply. I did get it "professionally" installed, but I use that term loosely as I had no end of dramas. The amp continually cut out (due to them selling me a 4ohm stable amp but wiring the sub to 2ohm) and making the internal volume of the box to be 62litres where the sub reqired 35l. I have since fixed both of these myself (rewired sub to 8ohm, though the amp doesn't deliver the recommended 300watt that the sub wants) and put an internal wall in the box to make it the right size.

As the sub is running through a line level converter (not sure what model they used) on the front speakers, I cant really play with the bass too much as it creates distortion upfront.

Is there a better way of getting the signal (I read that the voltages the pre-out puts out is very low voltage?). I'm open to suggestion.

[chalkie]

You should invest in an lc6 with bass control and fit it between the head unit and amp. Wiring the fronts and sub all of the front is the best way to go for many reasons. One, with the rear speaker only running of the deck you would have to splice into the rears to run the sub effectively halving your signal which means you have to turn up your gain giving you more distortion. Two, you will have a far more balanced system it you wire it up as follows.

-Head unit front speakers to lc6 which allows you to split the signal into fronts and sub (you can also control rca voltage and stop cliping at the lc6 before it gets to the amp allowing you to turn the gain down on the amp giving better SQ)

-Lc6 to amp with rca's (amp must have built in cross-over)

-Amp to speakers

-Rear speakers from deck

Wiring this way will allow you to tune the system properly. Set head unit to rear only, turn volume up until the speaker start to distort and than come back one notch. This gives you the maxium head unit volume. Now set head unit to the fronts (disconnect the rca for the sub at the amp first and turn the gain right down), than turn the volume up to your head unit max and start turning up your gain until your happy. Now turn volume down (disconnect front speaker rca's and refit sub rca's), turn volume back up and adjust the gain. This is a very good starting point now you can adjust the base using the remote sub control from lc6 and play with your coss-over point and you should be right.

Chalkie.

Edited 16/02/08 11:14 AM by chalkie