High vs low damping factor in amps (Bass "suspension")

[terryforsythe]

Here are the charts of damping ratio vs frequency:

With passive crossovers:

All active without passive crossovers:

 

[livinon2wheels]

Did you play at high volume when you did those subjective listening tests?

Your Wharfedale EVO 4.2 has 87 dB sensitivity according to the manufacturer. In reality, maybe an average of around 85 dB. That's based on what the manufacturer states vs what the test results show. In Wharfedale's case, they seem to be a few dB lower than stated. Check for example and compare the specs and test results for Wharfedale Diamond 220, Wharfedale EVO 4.1 and Wharfedale Linton 85th Heritage.

What does this matter? A few dB lower sensitivity than what the manufacturer states, so what. Normally it doesn't matter much BUT your Sansui AU-505 has 12 watts of power. IF you hear any difference between your amps when you listen, it may be because your Sansui AU-505 is driven into clipping, if you turn the volume up a bit with, say, a pair of 85 dB sensitive speakers. And an amp driven into clipping, you can hear that when it happens.
So that could be what makes you hear a difference between your amps.

https://www.hifiengine.com/manual_library/sansui/au-505.shtml

Your Yamaha wxa 50 is specified at 55 W into 8 Ohms.

While it may not be clipping in the absolute sense, the amplifier power supply may be sagging a little under load so that hard clipping is not happening but you are losing dynamics because of the sagging power supply voltage on musical peaks.

 

[antcollinet]

While it may not be clipping in the absolute sense, the amplifier power supply may be sagging a little under load so that hard clipping is not happening but you are losing dynamics because of the sagging power supply voltage on musical peaks.

If power supply sags to the point it cannot deliver the needed voltage output - that is clipping - soft - hard - whatever you want to call it.

Result is distortion. Not "loss of dynamics" whatever your definition for that is.

 

[Hayabusa]

Electric damping of a speaker is regulated by total resistance of the circuit. The higher resistance, the less damping. Total resistance consist of:
- voice coil resistance, could be about 4 Ohm,
- speaker wire and connectors, could be about 0.1 Ohm,
- amplifier resistance, which is specified as "damping factor".

Sansui specifies damping factor 50 at 8 Ohm, which means 0.16 Ohm.
Wxa50 is measured as 62 at 4 Ohm, which means 0.06 Ohm.
So we have total resistance for Sansui 4.26 and for wxa 4.16. The difference is about 2%. Do you really believe, that it matters?

We also need the equivalent series resistance of the crossover at the frequencies we want estimate dampening effect.

Edit: sorry, was already mentioned before...

 

[DanielT]

While it may not be clipping in the absolute sense, the amplifier power supply may be sagging a little under load so that hard clipping is not happening but you are losing dynamics because of the sagging power supply voltage on musical peaks.

@antcollinet replied I see. Can only add that clipping is not only the worst case amp distortion where it obviously sounds bad (unless you do it for artistic purposes, which on the contrary can be really cool) but it is a gray area. It is also individual, the level of distortion when it becomes audible/irritating that is.