Carputer, 3 amps, 2 way active?

**GreenBeast** · 07-05-2005, 11:20 AM

right in the advance planning stages at the mo and i'm now coming onto the issue of connecting everything together

i have searched for hours and hours today and haven't found a definitive answer to my questions.

i currently have 2 identical 2 channel amps. i am using one to power my sub ( power wise they are perfectly matched) and the other used to power some 6x9s (now gone)

now i'm planning on buying another amp and replacing all my stock components this time round.

if i buy a 4 channel amp can i use it to power the woofers and tweeters up front for better clarity (2 way active??)and then the remaining 2 channel amp to power the rear components through normal crossovers?

how would i go about wiring up this configuration?

also i have discovered that sound cards (especially the onboard type i'll be going with initially) don't have high enough output voltages. how can i rectify this based on the fact that i'll have 6 channel output (although i find at home that this isn't very effective with mp3s, only films) and want the above configuration of speakers
should i just use one 1/8" output (front L/R) and some external device for splitting the signal?

thankyou very much and sorry for the lengthy post

**GreenBeast** · 07-05-2005, 12:21 PM

ok i think i've decided not to go active because of cost and hassle (but the cables are in anyway just in case)

so i'll probably justa buy a 2 channel amp in addition to my other two

the issue i can envisage (apart from low sound card output voltages) is that i run 6 channels from my home PC to my A/V receiver but the rear channels and sub don't do anything because mp3s aren't 6 channel audio. i can see that happening in my car. so should i just take the signal off the front 1/8"?

**sdashiki** · 07-05-2005, 01:20 PM

I used to have 3 amps, 2 for subs, and 1 4 channel for the other speakers.

Its better to consolidate and get a 5 channel or a nice 2 channel (or mono for subs) and a 4 channel for the rest.

As for the 6.1 audio: however you get 6.1 OUT of your carputer should come with software to control the 2 channel audio of the computer into surround sound of 4.1, 5.1, 6.1 or 7.1.

Taking the 1/8 line out would give you only two channels and how would you connect that to 3 amps? You need audio out from the PC into the 3 amps, a Sub channel, Front/Back/Left/Right. You may need to make the "center" channel split between the front left/right to keep fadeability from front to back

**GreenBeast** · 07-05-2005, 01:52 PM

thanks.

what about low output voltages? do i need line drivers or equalizers or what?

**Lu Bu** · 07-05-2005, 02:08 PM

you can use a line drive to boost low signals.

**GreenBeast** · 07-05-2005, 02:13 PM

ok i'll investigate that.

anyone know any good software for arranging the channel outputs? i.e. so that the sound goes to every channel and not just the front 2

**RFMan** · 07-05-2005, 10:40 PM

What you are describing sounds quite a bit like my setup. I am running a full 5.1 setup with my carputer. The crucial piece of hardware for my setup is my M-Audio Revolution 5.1 sound card. It outputs line level signals (2V, which is enough to feed directly into any amp I've used) for all channels.

In the software for the sound card, you can specify high-pass crossover points for all speakers, as well as distances from the speakers to seating position. It even has a built-in test tone generator.

The software can be configured to take a 2-channel inut and output it in surround sound to a 4.1 or 5.1 system, which I think is what you're looking for.

I use a 6-channel amplifier for may main speakers, a monoblock for my sub and one side of a 2-channel for my center. This will be different than your setup, but the same principles apply.

Whatever amplifier you choose to use for your tweeters, it's always nice to have a high-pass crossover built-in that can go to into the kHz range so that you can avoid using the passive crossover of the component set. I had a JBL amp that did this, and my current Zapco amp does it too, but it's not a truly widespread feature. If you can;t get your hands on an am that does this, simply set any amp to full range ans use the passive crossover inline with the tweeters.

Since you already have two 2-channel amps, you might want to use them for the front and rear main speakers, get another small 2-channel amp for the tweeters (tweeters are very efficient and require little power to produce accetable sound levels) and a nice monoblock amp to power your sub. In my opinion, this is better than a 4-channel amp that would most likely overpower the tweeters and underpower the subwoofer.

Of, if you can sell you 2-channel amps, you might want to consider getting a 6-channel with a monoblock. The JL Audio e6540 is a nice 6-channel amp and can be found reasonably priced. If you can afford it, the zapco 6-channel is a very, very nice amp also. Paired with a monoblock appropriate for you could have everything powered off 2 amps instead of 4.

**GreenBeast** · 07-06-2005, 08:11 AM

excellent thankyou for that!

sound pretty much what i want. not bothered about centre channel but everything else is spot on.
i'm gonna give some thought to the amps cos ideally like to not lose money by selling them but you may be right about the 6 channel and mono-block

with the 6 channel would i power front woofers with 2 channel and front tweeters with 2 channel and then rear components (woofers/tweeters together) with the final 2 channels?
in this case i'd need to get components that could handle more overall power in the front compared to the rear?

**sdashiki** · 07-06-2005, 10:32 AM

But with component speakers that come with crossovers is it not better to simply run the amps output at full range to the crossover and have IT do the freq. work powering the woofer and tweeter from 2 channels...? Which is what you proposed to do with the back speakers anyway...is there a benefit to hi passing 2 channels strictly for tweeters?

Anyway a six channel should be 2 front, 2 back, and 2 subs. I have a 5 channel that is 2/2/1 and i just bridge the mono channel for two subs.

Buying 2 sets of components (which is 8 speakers and 4 crossovers) and powering each with 2 outputs from the amp and the subs each get their own channel stereo, or bridging the last 2 mono.

**GreenBeast** · 07-06-2005, 11:52 AM

yeah thats another question..if i run the components like standard (i.e. one tweet and one woofer per channel) do i let the amps run all pass or high pass?