Relay to Switch Audio Signal

[jyl]

Oddball question here. I have been looking for a switcher that will allow switching from car audio source A or B to the amplifiers. The complication is that each source is five channels (LF RF LR RR sub). The switchers I’ve found are only two channel, and seem to be made for home audio.

One could build a switcher, but I haven’t found any 5 pole 2 throw (5P2T?) switches. I’ve seen an Instructable for building a 5 channel switcher, but it used three toggle switches and it seems silly to have to throw three switches, plus integrating that into a car interior won’t look very “factory”.

So, I thought a pretty easy way to deal with this would be to use standard auto relays of the SPDT sort, one relay per channel, and energize them all with a single switch.

Will this work? Will the relay coil introduce noise into the source signal?

[Gogar]

What is source A? What is source B? With not quite enough info I wonder if you're trying to create a very complex solution to a simple problem

[jyl]

Source A would be the original, period correct car stereo head unit in the original location in the dash.

Source B would be a modern head unit with Car Play, GPS nav, and all the goodies, mounted NOT in the dash.

Both use the same amplifiers and speakers.

The idea would be you use Source A (with Source B hidden away) when alone and enjoying the pure simple driving experience, and switch to Source B when on a family roadtrip with the spouse and kids whining up a storm. A single touch of a factory-looking rocker or button should instantly switch between sources.

[Gogar]

Great! My suggestion: ( I do enjoy this stuff and have my share of time put in)

"Source B" the modern hidden-away unit is the MAIN UNIT. Outputs of which are wired to your amps and speakers, as normal.

"Source A" the period piece is an AUX INPUT to Source B.

If 'Source A" is indeed period it has either a stereo RCA output (maybe even 4 RCA outs), or speaker outs only.

If it only has "speaker outs", buy a Speaker-to-RCA adapter and you are set.

Your modern unit almost definitely has a stereo RCA input.

When you want the nostalgia, set your modern "source B" to the Aux input and enjoy your nostalgic experience. The RCA outputs on period head units will change the RCA out volume with the volume knob, so you could adjust the volume without grabbing for "source B" every 20 seconds. You'll just need to learn the relationship between the two volume knobs.

When you need all the extra goop, you're all set as "source B" has been wired to its full potential to your amps and speakers, and your Front/Rear/Sub situation is handled by the modern unit, with no fuss.

[Pazuzu]

Are you sure that either of them are really 5 signal sources, and is your amp capable of 5 inputs? Are you creating an artificial surround sound in your car from basic stereo signals?

[Gogar]

I'm pretty sure he's just describing a STEREO setup with a subwoofer output, and a front/rear fader.

Hooking the period unit up as an aux input to the new modern unit is incredibly easy and gets it done properly. For like . . . 10 bucks.

[Pazuzu]

Originally Posted by Gogar

I'm pretty sure he's just describing a STEREO setup with a subwoofer output, and a front/rear fader.

Hooking the period unit up as an aux input to the new modern unit is incredibly easy and gets it done properly. For like . . . 10 bucks.

Go away you music and technology capable person, you're not needed here!

[jyl]

Well, this is why I consult the experts! Gogar, that sounds like a great solution.

What to use for each unit?

For the modern unit, I was thinking a Pioneer DMH WT8600NEX, which is a single DIN base unit with a 10” HD screen that is mounted to “float” out in front of the dash. The screen mount allows a range of vertical, horizontal, and tilt setting. All the controls and display are on the screen, which is connected to the base unit with a short cable. The unit has wireless Car Play and all the bells and whistles. Here is a picture; I’m sure we all agree this thing would look hideous in a classic car, in addition to blocking vents and controls and screaming “steal me”.



But wait, Pioneer sell the CD RGB150E extension cable that is 63” long and allows remote mounting of the screen. So, we just need to mount the base unit somewhere hidden, under the passenger seat perhaps, and mount the screen in a way that allows it to be either accessible to driver, or front seat passenger, or rear seat passengers (aka whiny kids) OR tucked away and out of sight.

How to mount it like that? Well, we all lusted after the Blaupunkt Berlin with stalk mounted controls:



At least, I hope we did; if not, look deep with yourself and resolve to be a better person. For the rest of us, how about remote mounting the DMH WT8600NEX screen on an 18” gooseneck stalk, mounted to the passenger side transmission tunnel? The gooseneck is available at https://snakeclamp.com/ and the screen could be moved to be accessible to front seat passenger, rear seat passengers, and even to the driver. Or, bent down to tuck away behind the passenger seat. E.g. in this E28, you could mount gooseneck base to the tunnel roughly below the passenger armrest (just an example, not my car):



Seem workable? I don’t know if the Pioneer is the best unit for this, it’s just the one I found. It’s pretty darned expensive, but oh well. I know some people use iPads in a similar way, but I don't think Carplay works on iPads?

For the vintage unit, it could be whatever Becker or Blaupunkt or Continental is in the car now, or maybe one could find a working Blaupunkt Berlin . . .

[greglepore]

Pretty cool. Why not just mount an inexpensive carplay unit in the glovebox?

[jyl]

Originally Posted by greglepore

Pretty cool. Why not just mount an inexpensive carplay unit in the glovebox?

I may not be understanding, but wouldn't it be hard to see and touch the screen, if it is in the glovebox?

[greglepore]

Originally Posted by jyl

I may not be understanding, but wouldn't it be hard to see and touch the screen, if it is in the glovebox?

Not for the passenger...but yeah. A gooseneck would be cool, but I'd want it totally hidden when not in use.

[jyl]

Originally Posted by greglepore

Not for the passenger...but yeah. A gooseneck would be cool, but I'd want it totally hidden when not in use.

Depending on screen size, gooseneck length, and type/location of gooseneck mount to tunnel, maybe the screen could be pushed under the passenger seat with the gooseneck out of sight. Or maybe the screen could be pushed to behind the passenger seatback, so out of sight to the driver.

An alternative I just thought of is to mount the gooseneck to the ceiling, so the screen can be pulled down to use or pushed up where something would hold it flush to the headliner, since the gooseneck alone probably won't.