Mixed signal with mono amplifier

[stoplustil]

Hey, I'm planning my speaker set where I want multiple signal input and subwoofer. I' also trying to keep low-cost. I'm using mono amplifiers with TPA3116D2 chip. So first I have to mix signals using resistors (1k - 10k). Next connect signal to amplifiers. Subwoofer amp needs connected both channels so there's another signal mixing. And now I don't know how to do it. If signal R1 (for example) comes in, there's one resistor leading to R2 and another to amplifier. If I'm thinking right, the signal will split to halfs with same resistor values and that's not good for R2 I guess. One solution is using much bigger resistor value leading to R2. Won't be the signal loss too high? And there's also one more question. I have to use the same resistor as at subwoofer amp before R and L amps right? Or it will cause unbalanced volume between subwoofer and RL channels or no? Thanks for help

amplifier: DC 12V-26V 100W TPA3116D2 Mono Channel Digital Power Audio Amplifier Board New 714890521629 | eBay

 

[PRR]

To avoid L-R crosstalk when some loads are mono, you need separate mix networks.

With two sources (no switch?), mix-loss is half. Many small amps have enough reserve gain that this is OK. Because the amplifier you link has no real specs, you must try it and see.

For mono L+R bass to mono woofer there is no mix loss. Excess bass may not be a problem. If it is, add a potentiometer on the woof input.

I would grab a fist-full of 10K resistors; or 5.3k or 3.9k if I had an overstock of those values. Anything 1k-10k, all the same.

 

[stoplustil]

Oh, that's good idea. I'll try it. And yes, these specs are not real. I've already found real in datasheet and on YT.

Thank you so much.