How to build a car "system" between mp3 player and speakers

Prof · 12-07-2007, 08:07 AM

Hello to all. This is my first post. I am a newbie in this car mp3 project (googling for a day!). I do not want a perfect sounding system. I do not want to install a computer at this time but leave it for future upgrade (can't spend that kind of money). I do want to hook up my mp3 player via line out or headphone jack to a car "system" without using radio/tape/cd player. What I mean is that I do not want to have a fm transmitter or stereo with line-in solution. This means hooking mp3 player and speaker and whatever "system" goes in between the mp3 player and the speakers. Reason is mostly to learn and having an option to add in a computer at some point.

Have:
- An mp3 player with head-phone jack.
- Car speakers (that came with the car - nothing fancy)

Want:
- An OK sounding system to hear mostly mp3 lectures and downloaded podcasts.
- As inexpensive as a working system can get.

What I think I need:
- A DAC that can convert my mp3 player's digital signal to analog.
- An amplifier to raise the volume.
- Something to adjust the volume. (don't know where it would be placed)

I am mostly not sure how it will all work together but from my little understanding:

mp3 player -> DAC -> Amplifier -> Speakers
Don't know how and where to place volume control.

Does the above layout make sense? Any advise will be appreciated. Also, if you guys can suggest specific parts with names it would help.

One thought is if I can use off-the-shelf external sound blasters? Usually they take USB signal and need driver software.

What I can do:
- As you might have guessed I am not very familiar with how an audio system works but I still can solder stuff without problem and my software skills are OK. So writing up simple software or making a simple circuit won't be a problem.

Thanks for reading.

Prof · 12-07-2007, 08:20 AM

Well, I just read this post:
http://www.mp3car.com/vbulletin/car-...-speakers.html

This suggests the following setup:
Mp3 player -> Amplified equalizer -> Speakers

Is this good enough?

Mylt1 · 12-07-2007, 08:36 AM

your headphone jack is not a digital signal. all you need is the mp3 player, a 2.5 or 3.5mm headphone jack to RCA cable, and amp, wiring kit for the amp, and wire to run from the amp to the speakers in the car. the vol control would be the vol from the mp3 player. problem is gonna be matching the output voltage of the mp3 player to the amp. in other words a lot of work that can be handled by just installing a $140 head unit that already has an aux input.

DarquePervert · 12-07-2007, 08:43 AM

Quote: Originally Posted by Prof

Well, I just read this post:
http://www.mp3car.com/vbulletin/car-...-speakers.html

This suggests the following setup:
Mp3 player -> Amplified equalizer -> Speakers

Is this good enough?

If the equalizer has speaker-level outputs, then it would work.

Prof · 12-08-2007, 02:30 AM

Thanks for ur help guys. So my "system" should be:

Mp3 Player -> Amplifier -> Speakers

I will need:
- Headphone jack to RCA cable
- Amplifier to Speaker cables
- An Amplifier

The amplifier should have the following:
- Can support upto 5 Volts of line-in signal as headphone signal is higer voltage than line-out.
- Can support my car speakers

I have a used 1998 suzuki swift (hatchback) with two rear speakers. I opened the casing and they turned out to be:
Pioneer Three way TS-E 6960
200 W max music power
60 W NOM power
4 ohm impedence
70 W RMS (rms value was found on a personal website so not 100% sure)

Now my questions are:
- Does above information look correct? I mean is it really what I should be looking for or am I missing some technical detail.
- What are the amplifier specs that will support my speakers?

Thanks a lot.

Mylt1 · 12-08-2007, 11:46 AM

you should have front speakers as well. really to do this correctly you should replace all the speakers with a matching set front and rear with an amp that matches the rms of the speakers. say 35-50w rms with a matching amp. you need to find out how many volts the MP3 player is putting out because you may need to boost that. im sure that its less than a volt. that is gonna be hard to match.

Prof · 12-08-2007, 01:32 PM

Hi Mylt1,
I am not sure what do u mean by matching set of front and rear speakers and also what does it mean that 1V output by headphone jack will be hard to match. I have read other posts and still have little understanding of the subject. Could you be more specific please.

Also, as I mentioned earlier, I have a suzuki swift which is a rather small car. What kind of "matched" speaker specs should I be looking for.

Thank you for your help.

brucedog · 12-09-2007, 07:42 PM

It's amazing what a person can come up with on a budget - and the sound quality can be surprisingly good.

My audio system in my 2000 Saturn wagon is currently as follows:
>Creative Zen M 30gb mp3 player
>Pyramid 446x amp (2x70 w)
>"Buttkicker" subwoofer amp
>MA audio 2x10" subwoofer box
>Pyramid 440 amp (2x35 w)
>Dayton indoor/outdoor 2-way boxes on swivel mounts, mounted at rear. Allows me to swivel out and blas the neighborhood.
>Other odd and assorted speakers.......

I bought Monster cables to interconnect it all, and ran a 5 meter cable from cockpit to rear of wagon to conduct headphone jack out signal to inputs of all 3 amps. Works great! The bigger the mp3, the more music ya can take along. I currently have 300+ cd's.

You see, you can turn the gain on yr amps up about 60-70 %, then use the volume control on mp3 player to adjust. It helps if the mp3 player has at least a 5-band eq built in.

The real fun is balancing the speakers volumes, so that you have the system sounding like you want. I shop primarily at partsexpress.com; their prices are right, and they have a LOT of selection in the way of ready to install eqpt, but also lots of necessary little parts to put everything together nicely.

I realize that this is not an audio forum, but as a l o n g time audio and computer hobbyist, I encourage you to ask a lot of questions, but also to get in there and try to put your system together using your own ideas.

Be careful, be very careful about not overloading your audio amplifiers. This means that you must learn how to calculate the total impedence (ohms) of your speakers, so that the amp doesn't overheat. Don't get creative if you don't know what you're doing.

Parting shot: I recently bought a car PC from mp3car. I really primarily wanted it for use to play really high quality music, ripped from my own cd's. It's in a mini case, has a wireless kbd and 7" touchscreen. Lots of other accessories, too. During this Christmas break, I plan to fire it up on my workbench and put it through rigorous paces, then do the installation in my Saturn. It doesn't have to cost that much, and the improvement in music quality will be big.

Best of luck.

Mylt1 · 12-11-2007, 01:29 PM

matching speakers is just that. you dont want to go overboard with this so its best to just buy 2 sets of the same speakers(matching set). as far as what brucedog said he is wrong. the gain is NOT a volume control. it is used to match the voltage output of the deck(mp3 player in your case) to the input voltage of the amp. not knowing what the output of the MP3 player is an issue because you have to find an amp that comes as close to that voltage as possible to get the best sound. what mp3 player are you using so i can look it up? also what did the speakers look like, where they round or oblong? im seeing 6.75" speakers all the way around. is this true?

greatwhite · 12-11-2007, 03:52 PM

Really, the least expensive and easiest way to go would be a decent headunit with an aux in.

Radio, volume control, cd player and amplification are all worked out for you.
Just hook up the power, ground, speakers and plug in the player and you're good to go.........