Need help with car audio

[P1X3]

I got rid of cheap audio player from my car and intend to install raspberry pie with a 8" display.

Initially I wanted to install small computer, but somehow I don't want to go this route anymore.

 

Mounting

Found a double din panel for aftermarket dual-din audio players. 

 

Display

Currently in talks. The display area is 176.64(W) X 99.36(H) which is couple millimeters smaller compared to dual-din us standard.

It's a 8" 800x480 resolution screen with touch panel. I can find a better panel, but then I will have to mod mount.

 

Computer/Device/Player

Since I have a $35 raspberry pi, I will be using it. Works for now.

 

Audio

Factory audio system is great, even though car is over 10 years old. Because of this I would love to keep factory speakers and amplifier.

The factory amp is 6 channels (FR,FL,RR,RL,RSUB,LSUB), and the output from raspberry pie is just a stereo 3.5

I ordered 2 channel amp that has 3.5 input and I think this just might work. Connect right side wires (FR, RR, RSUB) to right output wires of amp, and connect left side wires (FL, RL, LSUB) to, well, left output wires of amp. I think it should work, any thoughts, suggestions?

[helping]

You will need to verify that the RMS of both rear and front speakers are the same. How much did the amp cost you? You were better off buying a 4 channel amp + monoblock (or some amps have 5 channels for this exact purpose).

 

You don't need an amp with a 3.5 input, use an audio jack to RCA wire instead. In reality you only need one channel for the subwoofer, bass (in car audio anyway) is not separated into channels, so RSB and LSB are the same.

[P1X3]

You will need to verify that the RMS of both rear and front speakers are the same. How much did the amp cost you? You were better off buying a 4 channel amp + monoblock (or some amps have 5 channels for this exact purpose).

 

You don't need an amp with a 3.5 input, use an audio jack to RCA wire instead. In reality you only need one channel for the subwoofer, bass (in car audio anyway) is not separated into channels, so RSB and LSB are the same.

I think RMS are the since since the speakers are the same. However I am not sure if it's relevant since I'll be using factory amp + 2 channel amp with input.

Factory amp has 6 pairs for inputs which usually comes from factory or aftermarket stereo. I'll be connecting 2 channel amp to those 6 inputs.

For some reason it makes sense to me, however it does not mean that it's right way or even a good way.

 

The amp was $50 and I got it for $17+S&H

[helping]

I think RMS are the since since the speakers are the same. However I am not sure if it's relevant since I'll be using factory amp + 2 channel amp with input.

Factory amp has 6 pairs for inputs which usually comes from factory or aftermarket stereo. I'll be connecting 2 channel amp to those 6 inputs.

For some reason it makes sense to me, however it does not mean that it's right way or even a good way.

 

The amp was $50 and I got it for $17+S&H

Crossing that many wires onto one output might not be healthy especially considering possibilities of differing ohm loads from the subwoofer. Note that wiring in series will add together ohm loads onto the amp, and wiring in parallel will divide ohm load by the amount of speakers. If your amp cannot handle low enough ohm loads in parallel it might very well die in a firely explosive blaze. If your ohm load is too high as in with a series setup it might not have enough power to drive everything.

 

I'm not entirely certain how it would interact with two speakers and a subwoofer wired onto one output because I've never heard of that scenario, but you will have no LP/HP filters whatsoever and setting gains on anything will be a problem as well.

 

Link to amp? 50$ would make me skeptical..

[P1X3]

Crossing that many wires onto one output might not be healthy especially considering possibilities of differing ohm loads from the subwoofer. Note that wiring in series will add together ohm loads onto the amp, and wiring in parallel will divide ohm load by the amount of speakers. If your amp cannot handle low enough ohm loads in parallel it might very well die in a firely explosive blaze. If your ohm load is too high as in with a series setup it might not have enough power to drive everything.

 

I'm not entirely certain how it would interact with two speakers and a subwoofer wired onto one output because I've never heard of that scenario, but you will have no LP/HP filters whatsoever and setting gains on anything will be a problem as well.

 

Link to amp? 50$ would make me skeptical..

 

So this wouldn't work ehh?

 

Edit: I realized that i messed up left&right side between the amps

[leipero]

Drawing1.png

 

So this wouldn't work ehh?

 

Edit: I realized that i messed up left&right side between the amps

Splitting a channel should work, there is no reason not to work or to have any influence on output device, problem is, why you need 1st AMP? Most (and i assume that factory) AMP's take low level input signal (same as PC can deliver). So, you have low level output signal from raspberry pi, just split it and connect to factory AMP. Why complicate it for no reason?

 

3.5 jack have one ground and two channel lines, take ground for all 6 channels, take left for all left channels, and right for all right channels.

[P1X3]

Splitting a channel should work, there is no reason not to work or to have any influence on output device, problem is, why you need 1st AMP? Most (and i assume that factory) AMP's take low level input signal (same as PC can deliver). So, you have low level output signal from raspberry pi, just split it and connect to factory AMP. Why complicate it for no reason?

There are no exact specifications for factory amp, but I do know that factory stereo had pre-ampted output to amp. That's why I thought it would be a good idea, but I am probably wrong.

On other hand, I'll mount that sub under passenger seat, and I guess volume controls will be near by. Doubt that I will ever change it.

[helping]

Drawing1.png

 

So this wouldn't work ehh?

 

Edit: I realized that i messed up left&right side between the amps

When you show it like that it makes a bit more sense, why are you routing an amp to an amp though? Can you take a picture of your factory amp inputs?

[P1X3]

When you show it like that it makes a bit more sense, why are you routing an amp to an amp though? Can you take a picture of your factory amp inputs?

 

 

It's just one socket that has all the inputs, outputs, and everything else. 

 

First reason for additional 2 channel amp is because I thought that running audio out of raspberry pi/android/player wouldn't have enough juice to push audio to factory amp.

For example if 3.5 device outputs 1.5V and I have to connect it to front, rear, sub inputs of factory amp, then something might go wrong. At least that's what I thought.

[helping]

proprietary design makes things difficult l:

[leipero]

 

It's just one socket that has all the inputs, outputs, and everything else. 

 

First reason for additional 2 channel amp is because I thought that running audio out of raspberry pi/android/player wouldn't have enough juice to push audio to factory amp.

For example if 3.5 device outputs 1.5V and I have to connect it to front, rear, sub inputs of factory amp, then something might go wrong. At least that's what I thought.

More chances to go wrong is with more power. Also, you could be right, that factory AMP needs more power in input, but i really doubt it, you really need to test it first, and see if signal from rp is enough.

[P1X3]

So I received the 2 channel amp today. It's about the size of two hands put together. Going to test with and without it tomorrow.

 

Edit

The board inside the 2channel amp is PA35X, and I was able to find a product that uses one (http://www.performanceaudio.com/item/Radio-Design-Labs-RDL-HD-PA35X/24756/)

The amazon advertises it as 300W amp which is kinda crazy considering the size of the amp.However, in my case it's a good thing because 35W is about as much as any aftermarket stereo can output.