4 Channel Stereo to Mono Output

[sick472]

Sorry for posting this here, but my patience is running out in the electrical section for Truck Audio (it seems a bit slow over there). MODS - you can delete without prejudice should you be so inclined, but it does apply to those of us that contend with the lack of audio space with the fuel tanks in the cab...

Now, I'm nowhere near a stereo guru so be easy on me...I am wanting to make my Sony DSX-GS80 4x100W car stereo drive the 4 speakers, but in mono for each. It also has the RCA connections for a sub which I will be using a compact sub woofer under the seat. I assume the sub woofer will not be affected should I succeed in making the 4 speakers mono.

With the fuel tank behind the seat of my 72 C10, I am limited on space for speakers and decided to build a center console to put 6x9's in. One faces the driver's legs and the other faces the passenger's legs. I will be mounting smaller speakers under the seat facing forward. This is not very conducive to the effects of stereo sound hence making it all mono. I am just wanting decent volume and not an unbalanced sound in the cab.

I have read that a single speaker can be made to produce mono sound by using the "+" of one channel and the "-" of another. This is great for those with the single stock speaker in the center of the dash, but can it be used to turn all the speakers to mono?

If I was not so worried about ruining my new stereo equipment, I would try to...

Use the front left "+" and the front right "-" for the smaller left speaker under the seat and the rear "+" and the rear "-" for the 6x9 on the left side of the console. Vice-Versa for the right speakers.

Any thoughts from those with more stereo knowledge?

Some unfinished eye candy for the photo lovers. I still have to add cup holders, sand and stain...

[toms68cst]

I think I would just power each speaker off of one of the four amp channels. There might be a way to set your head unit/source to run mono before it gets put into the power amps.

I don't think you will loose anything running in stereo anyway.

It sounds like you are talking about a series-parallel set up to the four speakers but that would only work (Probably not very well) with one power amp output. You also would only have the one 100w amp powering all four speakers.

I am a member of audiokarma.org. They have a very active board. I think they have a forum for car audio.

[toms68cst]

Also, I'm almost certain all the speaker connection negatives off your amp are all connected internally (and to vehicle ground.) so you probably can't run the + to the - of another channel without frying something.

[dmjlambert]

4 ways to do it that I can see:
1. Find a setting in the stereo that can downmix to mono (it probably doesn't have such a setting but you never know without reading the manual)
2. Play only media that is mono. For example, downmix the mp3's to mono using your computer, that you will play through your phone. Or, some phones may have a built-in downmix to mono in the accessibility settings. For example, iPhone has in the accessibility settings a Mono Audio on or off setting.
3. If the stereo has RCA line level outputs, connect 1K resistors to the center terminals of left and right channels, and you can combine the other ends of the resistors together to achieve 1 blended channel. This is called a summing circuit. Then feed that sum of the channels into a separate power amp. Don't use the stereo's internal power amp. You don't need to sum 4 channels, just sum a set of left and right channels, pick front or rear.
4. You can also just buy a summing device like this one, and use it between your stereo's line level outputs and a separate power amp. https://www.newark.com/mcm-custom-au...er/dp/25AC5154. This is probably what I would do.

[sick472]

Thanks for joining my thread folks...I agree with Tom that the stereo effect is probably a minimal nuisance. I will know in a couple weeks when I get all it all wired up. I'm just thinking ahead and trying to learn a little as I go. My goal is to get it to be mono with the head unit & speakers alone.

The stereo has no MONO setting, too new I guess. I wish it did.

The Sony High Output head unit has a built-in class-D amp (whatever that means) that claims it puts out 4 channels of 100W. However, it states that it only has 3 channels available (maybe they mean 4 amped channels - front left and right along with the rear L & R)...

Channel 1 – Front left and rear left speakers - (Not RCA, Just wires)
Channel 2 – Front right and rear right speakers - (Not RCA, Just wires)
Channel 3 – Subwoofer (mono)

It does have RCA jacks for the Front and Rears, but I think I lose the internal amp and would have to supply one. I will be using the wire hook-ups instead that also come out of the back of the unit.

I do not plan to run an amp for the front and rear speakers. I bought the Focal RCX-690 6x9's and will be using some repurposed speakers from a 95 Cadi. They all sound very good to me and will keep the budget in check. I will also be using a mini sub woofer utilizing channel #3.

IF I understand my web research (Big IF)...So long as the head unit speaker channels are "Bridged", I should be able to connect the "+" from the front-left to a single speaker and then connect the "-" from the front-right to that same speaker and achieve a mono sound. Problem is I get lost in the terminology pretty quick when doing my research and I can't find out if the head unit is internally bridged (whatever that means). Non-Bridged units probably use a true ground for the "-" speaker wires. Best I can tell bridged units have the "-" out of phase with the "+" wire.

I'm talking out my rear diff, so take it with a table spoon of sugar!

[sick472]

I tried crossing the positive and negative lines as I described above after getting some reassurance that it "shouldn't" damage anything from the audio shop that I bought my equipment from.

It certainly knocked the stereo affect down alot, maybe all the way. I learned that my ears are not that perceptive. It also dulled the sound a bit along with the lowering the volume by, maybe, 5%. I was also having some other issues (wire noise interference) so I focused on them instead of the mono/stereo test. I will be trying it again soon and be using some channel specific test tones to really test how much it kills the stereo affect.

At this point, I doubt the stereo effect will bother me more than the duller sound and volume loss. We'll see!

[ChevyRacefan]

My I ask why you want the sound to be in mono? You will be giving yp a bunch of sound, and making the install harder than it needs to be.

[sick472]

Originally Posted by sick472

...With the fuel tank behind the seat of my 72 C10, I am limited on space for speakers and decided to build a center console to put 6x9's in. One faces the driver's legs and the other faces the passenger's legs. I will be mounting smaller speakers under the seat facing forward. This is not very conducive to the effects of stereo sound hence making it all mono. I am just wanting decent volume and not an unbalanced sound in the cab....

None of my audio equipment has been sound tested in the cab yet...so, this mono/stereo exercise may be mute (moot -sorry, poor pun attempt). My suspicion is that I will have to turn the balance strongly to the passenger side to help with the stereo affect as the driver side 6x9 will be pointing towards me and the passenger side away from me. I'd rather have consistent volume across the cab than true stereo...assuming no loss in general sound quality.

[ChevyRacefan]

Originally Posted by sick472

None of my audio equipment has been sound tested in the cab yet...so, this mono/stereo exercise may be mute (moot -sorry, poor pun attempt). My suspicion is that I will have to turn the balance strongly to the passenger side to help with the stereo affect as the driver side 6x9 will be pointing towards me and the passenger side away from me. I'd rather have consistent volume across the cab than true stereo...assuming no loss in general sound quality.

Put the 6x9's under your seats, or in the cab corners.

[sick472]

Originally Posted by ChevyRacefan

Put the 6x9's under your seats, or in the cab corners.

That might work on the passenger side even though the seat would muffle it's sound a fair bit. But, putting it in the corner with the gas tank on the driver's side...I might as well put it in the glove box (lol)...it's tight back there. My 85 K20 has 6x9's in the cab corners and it really holds them back. Functional, Yes, but could be better.

The 6x9's are going in the console and the other 4 speakers (mids and tweets) are going under the seat facing forward with the compact sub under the center of the seat. If it was not for the parking brake pedal I would consider the kick panels for speakers, but even that would be difficult with 6x9's.

Originally Posted by sick472

...and decided to build a center console to put 6x9's in. One faces the driver's legs and the other faces the passenger's legs. I will be mounting smaller speakers under the seat facing forward...

[ChevyRacefan]

Originally Posted by sick472

That might work on the passenger side even though the seat would muffle it's sound a fair bit. But, putting it in the corner with the gas tank on the driver's side...I might as well put it in the glove box (lol)...it's tight back there. My 85 K20 has 6x9's in the cab corners and it really holds them back. Functional, Yes, but could be better.

The 6x9's are going in the console and the other 4 speakers (mids and tweets) are going under the seat facing forward with the compact sub under the center of the seat. If it was not for the parking brake pedal I would consider the kick panels for speakers, but even that would be difficult with 6x9's.

Me, I would get 6x9's with separate tweeters (jbl make a nice set) put the woofer under the seats, and the tweeters in the rear corners up high.
or get 6.5" separates, they will be cheper than the jbl 6x9s.
And put the woofer under seat and tweeter in corners.
My truck already had the doors cut ,so the speakers are in the rear corners of the doors.