speaker Q

[malcom_xavior]

Hi all, I'm relatively new at this game and want to know a little about how I should go about seting up a great audio system in my car, I've yet to buy a deck (but I'm looking at alpines), but I've installed a cheap 400 watt 4 channel amp, which I plan on conecting to my two front speakers and bridge the other two chanels to a subwoofer in the back, I've got rear six by nines but was wondering if I should just eliminate them. My front speakers are a pair of off brand three ways, but I'm planning on upgrading to 6.5" woofers with fourth order lowpass filters that I plan on making (+24 db/octave) and 1" tweeters with second order highpass filters (+12 db/octave). I'm not so sure I'm going to make a filter for the single sub, because there is one built into that channel of the amp. Also, I was wondering if there are some cheap ways of adding more power to the system, such as combining the unused channels of the deck and putting them in line to the speakers as well since everything will be conected through the amp, which will in turn be conected through pre-amp channels with rca jacks. I read a post with a similar question, but there was a conflict between two answers on whether you could safely do this or not. I highly anticipate some good answers, I hope I'm not asking any dumb questions either.

[udip]

Hi !!


1) ...."I've yet to buy a deck (but I'm looking at alpines), but installed a cheap 400 watt 4 channel amp"....

If you want great system don't use a great deck to
run a cheap amp....You should go for a better amp.

2) If you have a subwoofer, use the rear 6*9 speaker for
rear fill....use a bandpass filter set to ~300-4000hz
and have them in thier own enclosure so they will not be
affected by the subwoofer...
Usually a pair of coxial speakers will be good for rear fill,
but if you already have 6*9, that's ok.

3) For the front speakers go for a good set of components...
with an external crossover...
It's not worth using 24db crosoover.... and specially not 24db
for woofer and 12db for tweeter (they sould be both at the
same order)

4) "...Also, I was wondering if there are some cheap ways of adding more power to the system, such as combining the unused channels of the deck and putting them in line to the speakers as well since everything will be conected through the amp..."

Don't use it... there is no point doing so, cause it wont give
you more power!!


Udip.

[malcom_xavior]

I plan on buying a seperate amp around 500w or so to power the front speakers, and using a seperate amp, bridged, for an 8" sub around 1000w. I've heard that rear fill only sounds okay in certain situations. should I just power the 6*9s with the deck?
I also had a question about picking speaker values. Do you pick a speaker rated for the max power of your amp or should you pick one rated over the power being provided just for extra protection?

[udip]

Hi,


Yes, you should use the deck for the 6*9, it's a waste to use
a seperate amp to run them.

About the speakers, they should be rated at least as the amplifier, and even better about 1.5*amplifier power.


Udip.

[richie00boy]

I'm going to add more confusion

I like Alpine decks so you should be OK there.

Don't bother with rear fill. Do it properly at the front and it will sound better.

Crossovers. You would be better with 24dB on the tweeter and 12dB on the woofer. That way you protect the tweeter more from damaging excursion, and the woofer will have a rolloff anyway so will likely be an acoustic 24dB anyway.

You can't parallel headunits and amps to get more power.

Wattage ratings. Here's where most people get it wrong. As long as the speakers are rated between 50-150 watts RMS then you will be fine. If you go for mega power speakers they tend to be less sensitive so you actually need loads of power to drive them. It's more dangerous to have an amp lower rated than the speakers. What causes blown voicecoils is driving an amp to clipping so it produces massive amounts of high frequency energy. Having an amp rated 2x speaker power is perfectly safe.

[pks71]

Adding speakers in the rear for fill just throws off the time allignment. By this i mean the front speaker soundwaves will reach your ears sooner that the rear speakers because they are closer. Less speakers and proper speaker placement is the best way to acheive audiophile sound.