Another pc sound -> car speakers question

Juz · 10-08-2002, 05:05 AM

Sorry to post another thread on this similar subject but I'd like clarification for my particular setup rather than hoping it's like somebody elses

Anyway I've got an EPIA5000 mini-itx board with onboard AC97 sound. I have bought an indash TFT which takes up my DIN where the old radio headunit was, and I was just going to buy a new headunit with AUX-IN and put it in the glove comparment, then send the audio signal from the onboard sound to the headunits AUX-IN, then to the car speakers.
However after reading a couple of other threads I've realised I can not bother with the headunit (I'm not bothered about radio, I plan on using DAP USB directly into the PC later on) and instead send the audio from the onboard sound through an amp and into the car speakers? Is this correct?

My car is a '93 Peugeot 106 and I'll be using the 4 stock speakers (don't have the funds to replace them any time soon either), so if the above is correct could somebody please recommend to me what kind of Amp I should be looking for and also what cables or connectors I may need. I'm very much not an ICE expert so I'd appreciate it if replies could be kept on simple terms I'll understand

Thanks!

magnetik · 10-08-2002, 05:15 AM

posts on subjects certainly do become the 'flavour of the month' round here lately...

and running sound cards to amps directly is the current trend... and its good to hear. I have been doing things this way for close to 3 years - after giving up on head units..

your exactly correct in your assumptions.... get an amp and run the sound card output into it.... then onto speakers...

with 4 speakers you may wanna get a 4ch amp and keep the levels LOW.. for the stock speakers (they wont handle much!) but try to get a good qual band name one ..... Clarion/JL Audio/Pioneer/etc if you can.... silly getting a poor quality one, cause your next step will be to want better speakers!

for a 4 channel amp you will need to split the two channels into four..... so left front and left rear will be the same "LEFT" and anway..... you may alot wanna couple the amp/soundcard with a pre-amp too..... giving you the ability of an equlizer and fader control too...

have a look at my website for ideas..... any more questions, post em here......

Juz · 10-08-2002, 01:28 PM

Excellent, think that covers about everything I need to know thanks

Oh one other thing actually - I've found a nice Amp (Sony XM-255EX) which is 2 x 55w RMS. If the output of the amp is more than my speakers will they still work ok or could it damage them? I'd rather not buy a really crap Amp now then have to buy another one when I do eventually upgrade the speakers and get a Sub, but just get a middle of the park one now so that it would work with stock speakers but be reasonable with new ones, is this ok?

jol · 10-08-2002, 03:08 PM

2x55 is maximum output, you can use that amp with your speakers, as long as you dont turn it up to 11

I'f i was in your situation, i'd buy a 2 channel amp(not that powerful but good quality), and wire the left front and rear to LEFT, and right front with right rear to RIGHT as you say that you have crappy speakers, the power of the amp divided into both front and rear should do the trick anyways.

later on when you get more money, buy another 2x amp and wire the small to the front and the new, bigger to the rear amps, or get a 4 channel and wire 2 of them to the back, and 2 to the sub (sub needs power).

i myself have a 4channel amp right now, powering the rear speakers and the bass. the front is powered by the internal amp of the headunit, its weak, but more than enuff to power the 4" coaxial speakers i got in front. later i will build all 8 speakers in the front, as it gives the best sound

(2x6.5,2x4"coaxial, 2x4" and a pair of tweeters, all pioneer aswell as the headunit)

Juz · 10-09-2002, 01:22 AM

Cool thanks

Think I've found the one I want to get - Rockford Fosgate 105s and like has been said I'll wire both f+r left to left and f+r right to right, then when I get better speakers buy another amp for rear only. Top plan

AVGeek · 10-11-2002, 10:38 PM

Be careful about wiring up two speakers to one amp channel. Some stock speakers have weird impedances, and could cause the amp to overload and shut down or fry. If the amp is not 2 ohm stable, I would not even think about wiring two speakers to one channel.

Arby · 10-11-2002, 11:02 PM

I've been really happy with my Alpine MRP-F200. It's a 4x40 amp, and you can get one for about $200.

Juz · 10-13-2002, 01:55 PM

Thanks for the advice chaps, I ended up buying the Fosgate 105s for £130 - just waiting until I can find time to goto maplins and buy the cables I need and a trackball/touchpad, then it all goes into the car =)

claylong · 10-15-2002, 07:46 PM

I was attempting nearly the same setup (4 channel sound, with AC97), although i was getting a lot of noise on my first try. There are two possibilities, from what i hear on this board....

1. Onboard sound has too much interference. Too noisy. If that's the case, why does it seem that there are people running this setup.

Does anyone have onbard and CLEAN sound??

2. Noise from the inverter. Either caused by the EM field around the inverter, or the square wave (used to syntesize the AC sine wave), that causes the noise. Ok, now what do we do?

I have many people telling me - USB Sound is the ONLY way. I doubt that.

help me out, anyone running this setup?

magnetik · 10-15-2002, 09:23 PM

could be the inverter, have you hacked your PSU yet with regards to the filter circuit? (I cant praise that enough, as you all know!)
but I have my inverter setup running sweet, and it is in no way a true sine wave output...

onboard sound can be rather average, speaking from experence, but different boards use different chipsets... tho I have found the AC97 stock-standard one to be a little flakey.....

no USB sound is not the only answer... your correct in saying that... a good quality PCI sound card will do the trick....

check groundings of your equipment, etc, etc..... all the standard stuff really..

claylong · 10-16-2002, 10:19 AM

I looked for the filter circuit on the PSU, but this one does not seem to have one that I can find. I know that some psu's have that small cap between two of the power leads, but mine does not.

The only weird issue with grounding is that my inverter will NOT work if i have the computer grounded through the inverter. In other words, if I ground the case (which is done in the PSU) with the thrid pin on the AC out of the inverter, the inverter will not power up. However, if I disconnect the ground from the inverter and hook it up to the car's frame, the grounding circuit seems to be complete.

Thanks for the info. I will look into this.

Ohh, nearly forgot. How many people NEED to run a preamp in order to get the sound card's output high enough to work with the amp (without cranking the gain way up)?

Clay

Charliey · 10-16-2002, 03:54 PM

Im running onboard sound on an MSI KT3 board and it sounds great. Although this is not in a car, and it is a very new board. Old onboard sound tended to be much lower quality, but on new boards it works fine for mp3/basic sound stuff.

claylong · 10-16-2002, 05:50 PM

I appreciate the input, but what does that have to do with the subject at hand?

Andrew Chappell · 10-17-2002, 11:47 AM

It's showing that onboard sound can sound damn good (I have built a few kt3 ultra pc's recently and been watching dvd's with them in 5.1 surround - they sound truely amazing!) but is usually let down by other things, such as dodgy power / grounding.

Or at least that's what I thought it was

I've found the ac97 on my epia 5000 to be pretty good, although I haven't really tested it out in the car much cause I haven't built an enclosure for my display yet.

Cheers

Andrew