Faux Quad Possible for Auto?

Reading through lots of threads recently got me thinking:

It seems having discrete surround in one's auto is a rare proposition. You have to buy a certain car and even then it won't play all formats. AFaIK, no car ever has been made with a universal BDP, right?
But, almost every auto, for decades, has come with a CD player. Sure, that's only Redbook, but with road noise and uncentered seating position, speakers down near your feet and whatnot, is less-then-optimal resolution really a deal-breaker?
So I'm wondering, with all the discussion of devices that can produce faux-surround effects "on the fly," how feasible would it be to wire such a thing in to a car deck? Car speakers are normally situated for quad (or pretty close - 4 corners, more or less). We're already used to "dual-stereo" in the car. How difficult would it be to send some kind of processed signal back to the rears that changes things up a bit - producing a faux-quad effect, if you will.

You could put together a Hafler effect. It is passive and can be wired under the dash or in the trunk. Think of the Dynaco Quadapter. It isn't discrete but will give some depth to the sound. It is mainly wire and a few resistors. Schematics can be found online.

There were many "faux-quad" adapters back in the day. The Kraco is depicted and briefly discussed in this thread: https://www.quadraphonicquad.com/fo...-Kraco-quot-4-Channel-Quad-Sound-Adapter-quot

Many brands sold this kind of item: Speco, Audiovox, Olson Electronics, Lafayette, Kustom Kreations and Radio Shack's Realspastic, to name a few.

Here's an internal schematic of a common way this was done, based on Dynaco's (David Hafler) Dynaquad "decoder":

schematic from Audio Karma

Circular Vibes, I hadn't seen your post yet when I was creating mine, researching the link and schematic. Great minds think alike. Thanks!

As posted in the other thread, I picked up a Realistic Quatravox. If I can get it properly wired and working, great!
If not, no biggie. Will be fun to try though.

I've had old fashioned Quad (8-track) in an AMC Hornet, a Gremlin and a Javelin. I've also had modern surround (4.0 from disc) in my '04 Tiburon and in my '87 Daytona.

The best I would have to say is the Tiburon. Even with the speakers in the doors and facing eachother, imaging is excellent and a center stage is very prominent. The rears are about bicep-level and narrowly angle toward the front of the car, also creating excellent rear center and rear left-or-right staging. I want to buy a new car but simply can't give up how good the Surround sound is in the Tibby.

The worst I'd say is my Javelin. Two door speakers up front, two speakers in the parcel shelf facing straight up. For whatever reason, even with 2-channel stereos, the Javelin has never had a healthy center stage. It always sounds like the Front Right speaker isn't working and the phase is correct. The rears, since they face up, create a nice center-rear effect, but anything situated in the corners kind of gets lost.

The Hornet had four speakers in the door panels, each pair faces it's opposite. Good Quad Sound.

The Gremlin, I put the back speakers too far back. Limited by speaker size and space in that car - but the system is 100% vintage and super cool.

The Daytona has been the odd duck. Factory Chrysler 6-speaker system you'd think would be great for Quad but isn't. The dash speakers are very prominent and seem to subtract sound from the front door speakers. Like it's trying to send mid-to-high tones to the dash and bassy frequencies to the doors. I don't know of any sort of crossover in the wiring but I've found it best to just unplug the dash speakers. I will work on this. I had Surround in my Lebaron years ago (Quad-8) and I made that car sound amazing!

I sense an AMC trend here. I had my 1974 AMC Matador wired for Dynaquad (rear negatives crossed). The dealership thought I was nuts , but they did it.

edisonbaggins said:

Reading through lots of threads recently got me thinking:

It seems having discrete surround in one's auto is a rare proposition. You have to buy a certain car and even then it won't play all formats. AFaIK, no car ever has been made with a universal BDP, right?
But, almost every auto, for decades, has come with a CD player. Sure, that's only Redbook, but with road noise and uncentered seating position, speakers down near your feet and whatnot, is less-then-optimal resolution really a deal-breaker?
So I'm wondering, with all the discussion of devices that can produce faux-surround effects "on the fly," how feasible would it be to wire such a thing in to a car deck? Car speakers are normally situated for quad (or pretty close - 4 corners, more or less). We're already used to "dual-stereo" in the car. How difficult would it be to send some kind of processed signal back to the rears that changes things up a bit - producing a faux-quad effect, if you will.

Click to expand...

There is a new technology coming that will take advantage of the position of the car rear speakers and the driver off center seat position. Better yet, it doesn't require a special audio format, it works with CD, AM/FM Radio, mp3 player, smartphone bluetooth, DVD player, you name it. I've filled a international patent for this invention, it was accepted and there's some negotiation going on. I believe it's the first jaw dropping technology that isn't "surround".

Imagine a live Elvis Presley show, with this new technology It can put you on the stage in front of Elvis Presley and all the band around you, using a CD or mp3. No extra speakers is necessary, only the ones already installed on your car.

I Don't know how a Quad sound like because I don't have any material to test with, but I've demonstrated this to a few sound engineers, producers, Radio and TV's stations using their own material and they like it, a lot!

This is a picture of the prototype.

Intriguing!

A little wiring advice please!
This quatravox has the following wires:

Inputs:
Amp L & R
Amp Grnd

Outputs:
Speaker front L & R
Speaker rears L & R

So, I'm supposed to ground the unit, I get that, but someone warned about "chassi grounding." Should I not use the car deck's ground and instead run ground from the chassi to the quadravox?

Then, what do I use to feed the L & R inputs on the quatravox? The front L & R from the deck that would normally go to the speakers? The rear L & R? Does it matter? Is this thing assuming your car only originally had 2 speakers and you're upgrading to 4?

Thanks for any advice. Snide remarks and general jeering also encouraged.



:banana:

So, I have managed to get the Quatravox working in my Mazda Protege.
Oddly enough, I found out my rears have been out of phase since I bought the car (tinkered with them to address a buzzing/rattling issue), but that is corrected now.

The way I have it wired is:
Ground to ground
Amp left input on Quatravox to left pos out on deck
Amp right input on Quatravox to right pos out on deck

Rear speakers:
Left rear pos speaker out on Quatravox to same in for corresponding speaker
Left rear neg speaker out on Quatravox to same in for corresponding speaker
Right rear pos speaker out on Quatravox to same in for corresponding speaker
Right rear neg speaker out on Quatravox to same in for corresponding speaker

Front speaker connections run straight from deck to front speakers

It kinda throws ambience in the rears. Pretty cool. We'll see how long it lasts before blowing up!
If anyone has advice for how to wire it better, pray tell.
The confusing thing is that the Quatravox only has L & R inputs. No +, no -.
That may be what y'all was tryin' ta say earlier on.
@:

**footnote: I think I have the rear speakers wired as described... I'm assuming striped wires are positive on the Quatravox, though I've been unable to find a pin-out.
The stripes are negative for my car's wiring harness...
AfaIk, traditionally, striped is positive...

So, predictably, the Quatravox hasn't functioned properly. It does work, but intermittently cuts out. It comes back later, but cutting out at all is not cool.
I unwired it, but, instead of just putting my wiring back normally, I experimented a little.
I tried running rear left deck pos out to rear left speaker, pos between rear speakers and neg back from rear right speaker to rear right neg on the deck, but this resulted in only one speaker broadcasting the normal signal (or maybe mono?). Point is, the other rear was dead. Interestingly, adjusting the balance between left and right caused that one speaker to go from zero volume (at full left) to full volume (at center) to zero volume (at full right).
I was about to give up and just go back to dual stereo. But, on a whim, I decided to cross two remaining sets of wires.
I had the deck rear left pos connected to the rear left pos of the rear left speaker. I also had the rear right speaker neg connected to the rear right neg of the deck.
The fronts were left wired normally.
So, I crossed the two remaining pairs.
The result is very, very cool. If you adjust the balance all the way forward, you hear the normal stereo album.
If you adjust the balance all the way to the rear, you hear a VERY ambient, kind of washed-out, version of the album - mostly the reverbs, some flange, lots of highs, no bass!
BUT. If you adjust the balance to be equal front and rear it sounds super-full, hella cool. AND. If you put your ear near the rears, they do sound ambient and a bit flangy, but they sound full too, highs, mids and bass.
I'll post a couple of pics.

Not sure what happened uploading those pics, but here is essentially what I did:

Front speakers wired normally

Rear left speaker is connected to it's own positive wire from the deck, plus the positive that ought to go to the rear right speaker

Rear right speaker is connected to it's own negative wire from the deck, plus the negative that ought to go to the rear left speaker

I did this behind the deck, but could potentially be done in the trunk or where ever your rears are wired.

The effect this creates is cool to the point that I have renewed excitement over listening to my collection of stereo albums again.

I definitely recommend others try it and would love for a sciencey-type to explain what this wiring is achieving.

What you're hearing is the difference information. And, LR is in phase with the fronts, RR is 180 degrees out of phase.
By difference information I mean everything that is common to both channels is removed. Opposite of summed mono.
This could put extra load on the amp, make it run hotter, shorten its life, but I'm not certain depending on the design.

Interestingly, that you can hear anything from the RR connected to the two negatives means that this is not a common-ground amp. This could be why the Quatravox seemed to be cutting out, it is made for a 70's-style common ground amp. Hard to explain further but essentially it was partially shorting the speaker outputs to ground.

btw, the above Hafler circuit seems not quite right. I usually see it as pictured here: http://www.instructables.com/id/Surround-sound-for-free-it-could-save-your-marria/
Still, it would need a common-ground amp and could hurt modern ones.

quadsearcher said:

This could put extra load on the amp, make it run hotter, shorten its life, but I'm not certain depending on the design.

Click to expand...

Well then I only recommend trying it if you're cool with blowing out your car deck! I'm ok with the risk. Sounds VERY cool.

quadsearcher said:

LR is in phase with the fronts, RR is 180 degrees out of phase.

Click to expand...

The odd thing about this is the LR & RR sound very similar. As similar to each other as the Fronts do to each other.

LR & RR should sound the same individually (in this wiring). They both are the difference (L-R) information derived from stereo. Phase between two signals can only be heard when you're in-between the speakers.

The fronts should be normal stereo. Try mid-era Beatles stereo mixes like Rubber Soul. If vocals were recorded on the left only, with this (unusual!) wiring, vocals in front would still be on the left, but back channels would hard to tell apart from each other. I'm guessing in this example we would hear vocals in both LR and RR. With less extreme stereo mixes, we would hear very little vocals in back. The back would be just that shimmery, ambient, almost ghostly sound.

I've tried the both-postives-to-the-speaker thing with an old common-ground stereo and it is cool, the middle drops out and you can only hear the extreme difference between the two channels. I only tried it with one speaker as the back, saw it in an old Radio-Electronics magazine. Trying to understand what I was hearing made me think a lot about phase. I read a lot back then.

"LR is in phase with the fronts, RR is 180 degrees out of phase." Sorry, that's not quite correct. I meant to say something more like "The backs will sound alike independently, but they both have a complex phase relationship to the Fronts". I don't have the math ability to explain it more correctly.:violin