How can I tie two inputs to one amp or 2 amps 2 one speaker ??

microtime · 07-29-2005, 08:53 PM

I guess I’d have to say I’m a newbie – that hurts.

I’m a PC tech, I’m building something so un-necessary that it’s a good thing. I have everything figured out except the speakers. I have already read through some of the audio posts but haven’t seen exactly how to do this. I see lots of you don’t want to do this but in my case I do?

I have a Mocha PC, the all in a little box PC, no ATX power supply, tougher to work with but fits entirely! In my console – finding a quality 19volt scientific like power supply was a pain.. I have PC controller card to turn it on and off, 2 batteries, Oronico gold w external antenna, extra amp, yadda, yadda , yadda. It will be nice.

The problem is audio. I want, and yes I want, to continue to use the stock HU, it ties into a decent sound system, is easy to use, has a built in changer, and most importantly, I want to listen to music, or the news, while I want the GPS to tell me when to turn left or right. I want separate volume controls for both. I want to turn up, or down, the volume one the HU and still have the gal telling me when to turn. All that said, all the posting are about extra amps or running the HU through the input of the PC. Thus I can”

1. Run the HU through the PC sound inputs. Crappy solution here as my PC has basic built in only sound. I don’t want to loose this or be tied into using the PC to control the stereo
2. Put in a separate amp w separate speakers – good but not a lot of room for an entire separate set of speakers
3. OPTION #3, either (a) find a way to splice inputs to the amp for the HUD, and amp on, and tie in the PC before the amp, if there is an amp on an 97 Avalon, or (b) Splice the amp outputs to the existing speakers, maybe put in diodes?

Does anyone know how to make this work. Again, I want the factory stereo to work as-is and tie in the PC for GPS, DVD’s and MP3’s through the same speakers but how??

RedGTiVR6 · 07-29-2005, 09:39 PM

ummmmmmmmmmmmm

yeah........

I'll just post to this to see if anyone else can come up with anything....i'll be interested to know

SickVette · 07-29-2005, 10:54 PM

Well...I did a little searching and came up with one possible easy to use product but I am not sure it is made anymore by Peripheral Electronics. I can find out this weekend though. Unless there is a way to input audio into your radio you will need a switcher of some sort. You can make a manual switcher with some relays and a toggle switch that is easy. But not as cool as if it switched on it's own. Do you know if your radio controls a CD changer? Funny things I could point you to several products that would do the job for you if your car was a 98 Avalon.

walky_talky20 · 07-29-2005, 11:52 PM

Some 97 Avalons have an external stereo component amplifier and others do not. In particular, the 6 speaker system does not. The 7 speaker system DOES have a factory external amp. The seventh speaker is the subwoofer. So, if you have a subwoofer, than you have an amp. If you do not have a subwoofer, than you do not have an amp. This is from wiring diagrams available from Powerlibrary, not a Toyota repair manual, but I beleive the information is accurate. I can email you the stereo system wiring diagrams (pdf) if you like.

walky_talky20@hotmail.com
Later

microtime · 07-30-2005, 05:28 PM

It is a 98 Avalon, not sure why I wrote 97, does that make a difference?

Also, if there is a CD input I couldn;t have both running at the same time.

There must be a way to combine line level inputs?

accentsound · 07-30-2005, 06:28 PM

You can not do this with a unamplified stock system. The only wayt to accomplish this is with a externally amped system. Then you have to get a High level to low level converter for your HU. Then you can use a stereo input mixer to combine the HU and PC audio outs. The amp (4 channel most likely) will drive the existing speakers. But expect your stock speaker will not last long amplified. This is the only way you will be able to listen to music and at the same time hear the GPS. If you only wanted to have one at a time to listen to then all you would need is either a FM modulator or a HU with a AUX in.

microtime · 07-30-2005, 08:26 PM

Thanks,

I give up on the idea of 2 amps on one speaker. I know that I have a factory am now as well. i don;t mind replacing that with a better one. So how do I tie together, mix, two sources. i know radio Shack sells a cheezy mixer console, I own one, but is there a part for a car, and should this work?

greenman100 · 07-30-2005, 09:26 PM

Quote: Originally Posted by microtime

Thanks,

I give up on the idea of 2 amps on one speaker. I know that I have a factory am now as well. i don;t mind replacing that with a better one. So how do I tie together, mix, two sources. i know radio Shack sells a cheezy mixer console, I own one, but is there a part for a car, and should this work?

why cant you combine 2 amps on one speaker? I am pretty sure it'd work.

dont use diodes, they will chop the AC

mixer boards do the same as you are proposing, only at lower level (mix audio)

$5 says you can run 2 amps on one speaker.

Zebelkhan · 07-30-2005, 09:49 PM

I did exactly what you want to do. I built a switcher box with a simple relay and used remote turn on of my HU to tell it when to switch. Sound from carputer goes to this relay. If I am listening to my MP3s, the carputer sound, including GPS connects to the HU and comes out of the car's sound system. When I am listening to the car radio or play CD, the remote on wire on the HU switches the relay so now carputer audio gets connected to a small speaker and I can listen to GPS on that while radio or CD in playing on the sound system. My carputer sound is not amplified so I used a little amplifier from a hands free phone set up to raise its volume. It works great, but your HU has to have a remote wire for automatic switching, or you can just install a little switch to manually activate the relay. This is the exact relay I used.

http://www.allelectronics.com/cgi-bi...-12&type=store

greenman100 · 07-30-2005, 10:17 PM

Quote: Originally Posted by Zebelkhan

I did exactly what you want to do.

no, you didn't.

he wants to have both playing at the same time

lookinco · 07-31-2005, 06:15 AM

Quote: Originally Posted by greenman100

no, you didn't.

he wants to have both playing at the same time

With Zebelkhan's solution, he is able to play both at the same time. Radio/CD coming from car speakers while GPS coming from a small speaker.

And when he wants to listen to CARPUTER with his car speakers, just flip the switch!!!

Now my question is, how do I build a switch that switch between 2 different sets of 6 channel sounds? My headunit has 5.1 output and so does my carputer. How do I build a switch to switch between the two sources going to my amps?

greenman100 · 07-31-2005, 10:18 AM

Quote: Originally Posted by lookinco

With Zebelkhan's solution, he is able to play both at the same time. Radio/CD coming from car speakers while GPS coming from a small speaker.

And when he wants to listen to CARPUTER with his car speakers, just flip the switch!!!

Now my question is, how do I build a switch that switch between 2 different sets of 6 channel sounds? My headunit has 5.1 output and so does my carputer. How do I build a switch to switch between the two sources going to my amps?

no, he wants both coming out of his car speakers ideally

as for your question, use 2 3PDT relays

Zebelkhan · 07-31-2005, 03:30 PM

Quote: Originally Posted by greenman100

no, he wants both coming out of his car speakers ideally

I don't know much about electronics but I understand you should not connect two output sources with different impedence levels together as the out put electronics may get damaged. My solution separates the two circuits.

Believe me the GPS sound coming out of the little speaker is sufficient! It is very clear and its volume can be set to any level you want independently of the HU. Also, because I have the speaker mounted under the dash on the driver side, its sound is mostly directed at the driver so it does not interfere with the listening pleasure of the other passengers!

Now that I am able to turn the lilliput audio on when in VGA mode, today I plan to do away with the little extra amplifier and speaker and connect to the lilliput audio input instead for a more OEM look.

SickVette · 07-31-2005, 05:25 PM

Microtime......since you have a 98 there are adaptors available. I will check tomorrow with peripheral electronics to see what they suggest and if a part I know will work for you is still available.

greenman100 · 08-01-2005, 10:29 AM

Quote: Originally Posted by Zebelkhan

I don't know much about electronics but I understand you should not connect two output sources with different impedence levels together as the out put electronics may get damaged. My solution separates the two circuits.

Believe me the GPS sound coming out of the little speaker is sufficient! It is very clear and its volume can be set to any level you want independently of the HU. Also, because I have the speaker mounted under the dash on the driver side, its sound is mostly directed at the driver so it does not interfere with the listening pleasure of the other passengers!

Now that I am able to turn the lilliput audio on when in VGA mode, today I plan to do away with the little extra amplifier and speaker and connect to the lilliput audio input instead for a more OEM look.

then how do mixerboards work? they take signals from 2 sources (guitar, CD player, microphone) mix them, and give a single output

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