Powering 4 8-ohm speakers from this amp?

[wrybread]

I have this TPA3116D2 based amp:

https://www.amazon.com/gp/product/B08H54T98M/

It says it's output impedance is 4-8Ω.

I always thought that wiring two 8Ω speakers in parallel results in 16Ω, but from Googling I see that I'm wrong and that it equals 4Ω.

Does that mean I can connect 4 8Ω speakers to this amp (two on each left/right side)?

Any considerations or ways to improve the sound?

Do those passive speaker switch boxes do anything other than connect all the wires together? In other words would there be some advantage to using one of these (or an updated version):

Vintage 70s Realistic Speaker Selector Switch 40-125A 3 Output | Etsy

 

[rayma]

Yes, connect the two speakers in parallel, for each channel. Keep polarity the same for both speakers
and for both channels.

Resistors (or speakers) that are connected together in series add.
Resistors (or speakers) connected in parallel reduce the impedance (to half if they are equal).

Avoid speaker switch boxes with bridged amps like yours, it could short the channels together.

 

[wrybread]

Avoid speaker switch boxes with bridged amps like yours, it could short the channels together.

Possible to explain that a bit more?

Is the risk immediate, meaning if I try it and it doesn't blow, it works? Or is it something that could hurt it only over time?

 

[MikePP]

Possible to explain that a bit more?

Is the risk immediate, meaning if I try it and it doesn't blow, it works? Or is it something that could hurt it only over time?

Those switch boxes are junk - I used to sell them back in the 80's and they did damage to many plain old Class B amps , never mind Class D.


I would avoid using one, as you don't want to ever bring two Class D outputs together (+ or the - output).

 

[rayma]

Is the risk immediate, meaning if I try it and it doesn't blow, it works? Or is it something
that could hurt it only over time?

Immediate, don't try it.