It's a bit more complicated when you drive high currents because of the choice of every component affects the results of output impedance, quiescent current of drivers, harmonic distortion, dampening ratio which affects voltage from back EMF on low frequencies and thus "muddy bass".
Naturally from Shockley effects on Vbe vs Tjcn and same for diode, even if thermally matched may cause problems if the diodes have too small or too large a power rating and thus ESR with changes in Vbe from bias R's affecting output idle current greatly.
In order to determine the optimum Cap configuration, you need to understand that this amplifier is less than unity gain. So why is there loss and where is it? and why is that important to minimize the voltage attenuation for good low frequency response, but it will come at cost in idle power dissipation and bigger output C values rated for ripple current or load current in this case.
The question is simply comparing the capacitor impedance at some f vs the source and input impedance to see if the cap is impedance is significant. The differences in these two choices are minor compared to the other factors in R ratio design and Pd ratio selection for the Transistor and the diode so that they bias the output stage at the desired current to achieve low output impedance , which is essentially the source impedance driving the base /hFE.
Do you want to know more?
Then you need to define more specs.
Including: Pmax, Vmax, Load min, f min, THD max, min dampening factor ( usually 10 is cheap designs, 100 is better) Source impedance..
The lower your speaker impedance, like 4 Ohms , the more critical is thermal runaway settings and hFE matching between PNP and NPN, yet with +/5V you can easily generate 5W. A better design capable of 0.3W into 60 Ohm headphones or a few 8 Ohm speakers. Using 1N400x diodes instead of small signal 1N4148 must use a pot between diode string gives lower Vf changes but adding a 50 or 100 Ohm pot between them must be tuned for the speaker load and desired output power and mismatch of hFe. ( want them within 20%)
tinyurl.com/y9pdw3uv is an example my this in my latest simulation.
Note RMS power in speaker, you can change R value and RMS power from each supply (-ve) ought to be 30% efficient at best or 60% from both supplies. Note how pot affects each signal and DC minimum current. This gives very good dampening factors and DC response on output. You can DC couple input if source is 0Vdc.
- unknown hFE power transistors can created issues if not matched.
- these S8050/S8550 are graded for hFE, take note by suffix.