Combining two RCA audio signals

[MasterHenaz]

Hello!
This is going to sound pretty cursed setup so please don't judge.

I'm trying to add 2 passive speakers to my soundbar L/R channels. I'm using Aiyima A07 Max amp for the speakers.
So what I've done is I tap RCA cable directly to the soundbar element + and - to get audio to the amp. It works...
BUT
The soundbar element probably is not full range, so only the bass element of the speaker produces sound.
So then I tried tapping into the tweeter of soundbar and its the reverse effect. Passive speaker tweeter only produces sound and bass element is silent.

I'm going to need help with ideas on how to go proceed with this.


I'm new to this but here's what I think I know.
If I combine the soundbar tweeter and bass element RCAs to single RCA male then the soundbar will short circuit?

I'm willing to buy another A07 Max if the solution requires it
I'm willing to buy a preamp if the solution requires it
I'm willing to buy an audio mixer if the solution requires it

Why? The speakers sound great and add the extra warmth to the soundbar. Currently I'm using HDMI Arc splitter, but I can only get 2.0 audio through it to my soundbar while using the RCA output of speakers. This way the soundbar can process 5.1, 7.1, Atmos sound and still have the benefit of having better front stereo speakers.

 

[Rick Sykora]

Welcome to ASR!

As to your request, not quite following. What is model of soundbar? A wiring diagram would help too.

 

[DVDdoug]

Mixing would require a mixer and of course the passive speakers need an amp. (From what you've told us, you don't need another amp.)

You can build a fixed passive line-level mixer with a couple of resistors but you have to know how to solder. Or you can buy a little active mixer for around $100 USD. (If you're going to buy a mixer, I'd recommend active.)

If you have a full-range line-level signal you CAN split it with a Y-cable and send it to an amp and the soundbar (but you can't use a Y-cable the other way around).

 

[MasterHenaz]

Welcome to ASR!

As to your request, not quite following. What is model of soundbar? A wiring diagram would help too.

Thank you!

The soundbar is Samsung Q950A. I'm not very good at making diagrams but I'm planning to make it like this
TV to soundbar and inside the soundbar I tap the mid/bass element with + and - wire and convert it to RCA head and use that for the external amp which powers my passive speakers. Then I will do the same to tweeter element to produce rest of the sound. I'm bad at explaining this but here's a video of someone adding active speakers to upward firing full range speakers:

Mixing would require a mixer and of course the passive speakers need an amp. (From what you've told us, you don't need another amp.)

You can build a fixed passive line-level mixer with a couple of resistors but you have to know how to solder. Or you can buy a little active mixer for around $100 USD. (If you're going to buy a mixer, I'd recommend active.)

If you have a full-range line-level signal you CAN split it with a Y-cable and send it to an amp and the soundbar (but you can't use a Y-cable the other way around).

Thanks for the reply!
I know how to solder and that's how I'm planning to attach the wiring inside the soundbar once I get the sound out correctly.
I found a passive 4/1 channel RCA mixer for 10€ online with level control.

Why do you recommend active mixer?
New to mixers, so I don't have any insider knowledge
With passive I'm worried about bad internal wiring because it can't short circuit the soundbar element and with active I'm worried about possible latency currently.

 

[Rick Sykora]

Thank you!

The soundbar is Samsung Q950A. I'm not very good at making diagrams but I'm planning to make it like this
TV to soundbar and inside the soundbar I tap the mid/bass element with + and - wire and convert it to RCA head and use that for the external amp which powers my passive speakers. Then I will do the same to tweeter element to produce rest of the sound. I'm bad at explaining this but here's a video of someone adding active speakers to upward firing full range speakers:

If you are basing your effort on this hack job, good luck.

Am going to back track and ask what sound problem are you trying to solve? Also, do you have a budget target?

 

[Blumlein 88]

I fail to see how this is going to give you actual 5.1 surround. What soundbar are you starting with?

 

[MasterHenaz]

If you are basing your effort on this hack job, good luck.

Am going to back track and ask what sound problem are you trying to solve? Also, do you have a budget target?

The problem is that 1 audio source gives only signal for tweeter and 1 audio source gives for mid/bass element. It's like I'm trying to reverse a high pass filter.
The person before suggested an active audio mixer for around 100$. I asked for the benefit of active over passive, but he's yet to reply.
For budget if the parts are cheap like 10€ of that 4/1 RCA passive mixer I found, then it doesnt matter. If I need a 100$ active mixer its okay if its that much better and more future proof.

I fail to see how this is going to give you actual 5.1 surround. What soundbar are you starting with?

Q950A has its own rear speakers. And the sound bar has its own wide speakers for 7.1 and the whole system is rated for 11.1.4 audio.

But please this is not a thread how a real surround system is better than soundbar system.

 

[Rick Sykora]

You are jumping to how, please describe what you want to do sonically.

Why do you want to add left and right speakers to the sound bar?

 

[MasterHenaz]

Why do you want to add left and right speakers to the sound bar?

Well I prefer how these passive speakers sound!
The bigger elements, the bigger power and all the perks with better speakers compared to soundbar. The soundbar sounds good, but I'm the kind of person who likes extra umph.

After 5 years or so when I move from my current apartment, I'll switch to an actual reciver with speakers, but before that I'll go with this.

 

[Rick Sykora]

Ok, guess it should not be a huge surprise that little soundbar speakers are not keeping up.

Have you tried the stereo outputs on your tv?

 

[MasterHenaz]

Samsung only has optical and hdmi audio output which dont provide simultaneous audio output and my tv is 2020 model and 2021(and forward) support bluetooth audio with tv audio.
(Should have bought sony back then)

But yeah the HDMI audio splitter somehow disables the audio delay function and soundbar audiodelay only affects the rear speakers.

This "hack job" is probably the only solution to get this to work the way I want it to. Other solution was to look for an used AVR with hdmi zone B output (found one for 175€ but he sold it to someone else last year).

 

[MCH]

Maybe (only maybe) it is possible to do it digitally: extract the two front full frequency channels i2s to an external DAC:

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[Rick Sykora]

Have not seen many TVs without analog outputs here but have not bought one in a while. Sound bars are not popular with ASR members, might want to try posting your question to one of the AV sites.

 

[JeremyFife]

Sounds like you are making life complicated by trying to integrate the soundbar.
Take the bar away, build a conventional 2.1 (or surround) system?
Or, as suggested, try an AVR site to see what others have done.
Good luck

 

[MasterHenaz]

Maybe (only maybe) it is possible to do it digitally: extract the two front full frequency channels i2s to an external DAC:

Adding post-DSP SPDIF outputs to AVRs

Greetings! I thought it might be fun to share details of a current project, which involves modifying AVRs with post-DSP SPDIF outputs. This effectively turns any AVR into a fully digital audio processor with room correction, subwoofer crossover/time alignment and EQ functionality. The...

www.audiosciencereview.com

Thanks. Currently I'm going with the mixer route, so doing something this complicated (for me) is for last attempts.

Have not seen many TVs without analog outputs here but have not bought one in a while. Sound bars are not popular with ASR members, might want to try posting your question to one of the AV sites.

Yeah its harder to find analog output tvs now than with digital only. You dont need to think this as a "soundbar is bad" thing when you can also use this approch with any active speaker. This thread is a DIY project on mixing tweeter and bass/mid element signal for external amplifier.

Sounds like you are making life complicated by trying to integrate the soundbar.
Take the bar away, build a conventional 2.1 (or surround) system?
Or, as suggested, try an AVR site to see what others have done.
Good luck

It's not that complicated actually but I get your point.
Currently I'm not building a 2.1 (or surround) system. I'm combining 2 audio channels that are jacked off from speakers.

Thanks for the luck! I'll keep posting my results here once my mixer arrives.

 

[MasterHenaz]

Well the mixer sure took its time.

I have almost finished the project. I bought twisted pair RCA cable, snap it in half, opened soundbar and soldered everything correctly to tweeter and mid element.
Hook it up to RCA mixer and boom ONLY HISS from speakers.

My dad came to help and we checked that the soldering are done correctly. That the RCA mixer works. Soundbar works and switched RCA mixer power supply from regular 5V phone charger to 12V laptop charger (The mixer inputs 5-19V). When we switched back from the laptop charger to 5V phone charger everything started to work and sound was coming out as I planned. Sometimes it takes another person to look at it for it to work normally I guess. I packed everything together when he left and hooked everything up again and boom ONLY HISS again. Only one RCA in the mixer worked at the time but the second you plug another one in the goes to hiss in soundbar and speakers. I'm continuing the work a bit today and called my dad and told that the when I plug another RCA in it goes to hiss. He said (in direct translation that's where I need help) that the soundbar speakers are floating kind(?) and I need some sort of line separation?

My English is a bit off in this area so can somebody tell me what keywords to research or what products to find?

 

[audio_tony]

that the soundbar speakers are floating kind(?)

He means that the amplifier driving the sound bar speakers has floating outputs - this means that neither (+) or (-) speaker outputs are connected to ground. So you are probably shorting one side of the amplifier to ground, hence the hiss. The amplifier is probably a class 'D' which typically always have floating outputs (neither output is referenced to the power supply ground).
You will probably need to couple it with an audio isolating transformer.

You are making a *lot* of work for yourself here.

 

[MasterHenaz]

Thanks a lot! This helps me a lot!

Yeah this is not for everybody but I wanted it to work like this and this is what I've done.
Just for money it has only costed my 19€ for the active RCA mixer and 2-3 hours of work opening the soundbar and putting everything in place.
But hey it works! And I must be the first one ever to do something like this.

 

[JeremyFife]

Still puzzling over this, although it sounds like an entertaining project for you.

Doesn't your soundbar have HDMI out? Can you put that through an HDMI to RCA splitter and into your Amp?

No fun, and no soldering but it ought to work.

 

[MasterHenaz]

I have been using HDMI earc in -> HDMI+RCA out splitter but the splitters I've used only output 2.0 audio when RCA is plugged in.

Its okay because my soundbar has decent upmixing from 2.0 audio but you cant get any other audio than 2.0 in LPCM form.
The soundbar wont accept any commands from TV remote. I can only adjust the passive speaker volume via tv remote.
The soundbar also has like 30ms-50ms longer processing time than the passive speakers and for some reason I cant adjust the audio delay.

Well the 2.0 audio is okay because I consume a lot of content like that but still missing on atmos and everything else.
I fixed the remote issue with old logitech harmony remote that can control the soundbar with the same volume button.
I also gave the soundbar a lot of -decibels so negate the echo effect of audio delay but still benefit from the rear surrounds and subwoofer while they upmix to rear surrounds the stereo effect.

Doing it like this I get all the audio options the soundbar can accept, tv remote control and no audio delay (or non noticeable)

And no. No outputs on TV or soundbar that can do this. Only newer tv models support multiple audio outputs from samsung and thats via bluetooth only.

Next time I'm going with android TV and real AVR system. Been looking at Denon 3800h and 7.2.4 system with it but that's after 2-3 years.

Edit: And note to everyone. This is not hard or frustrating to me. I'm simply learning everything first time as I go and is actually quite fun. If you think this is hard or stupid then you should be the ones buying the soundbar and leaving electronics and AV equipment on DIY part at ease.
Thanks for the assist from everybody though!