Crossover in 2.1 amplifiers

Unable to find any specifications how 2.1 D amps (or in real 3 way amps) are resolving crossover. What order, what phase change etc. There are a lot of models in the market, like:
AIYIMA A03 Class D 2.1 Amplifier TPA3116D2 Bluetooth 5.0 2x50W + 100W 4 Ohm
DAYTON AUDIO DTA-2.1BT2 Class D 2.1 Amplifier Bluetooth with Tone Control 2x50W + 100W 4 Ohm
FOSI AUDIO BT30D PRO Class D 2.1 Amplifier 2xTPA3255 Bluetooth 5.0 2x125W+250W 4 Ohm
but no specifications, will the crossover also change phase and how?

I already feel stupid, how I can not find this information in specs or in forums. What I am missing here, is the crossover resolution totally different and the question is pointless?
 
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If it has variable crossover fr, than its typically from 40Hz to 180Hz. If its fixed, it is likely 150Hz.
When it comes to phase, should be flat.
Slope? Who knows. For sub should be as steep as possible, for satelites first or second order. Some 2.1 systems do not have high pass for satelites.
Manufactures do not provide full spec since its all junk you listed.
 
With MiniDSP when you switch on their digital crosses, these act like real ones. So there is phase shift heard immediately, and measured as well. So, on what bases the phase should be flat - how it is resolved?
When you split signal actively, and than you sum it back, good electronic crossover will yield flat fr response and phase again.
 
Plan is to replace old CreativeLabs computer sound system to a better one with 2.1. Sound levels are low as speakers really face me close up. That is, not much should be needed. Some Tang Band good full range accompanied with smaller subwoofer and some smallish D-amp for 3 way. This kind of simple setups should be easy to build also as phase coherent. Only problem is that most crosses are on higher order for subs, so the phase is turned heavily around crossover. In current CL setup this results as hole around 150 hz and it can not be fixed by equalizer, as signals eat each other at the region. So, is there simple solution for separating sub and full range without turning the phase around heavily (or listening to sub harmonics with first order)?
 
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I built small subwoofer active crossover circuit, as modified by Andrea Ciuffoli, easily found on his site. Its just two operational amplifiers.
But it has volume, crossover frequency and phase pots. It sums left and right signals. Then all you need is one mono amp for sub and one stereo amp for small fullrages. Just a cap for upper pass for small fullrange is all you need. Just to limit all below 100Hz to prevent overexcursion and distortion.

You seems to be overly obsessed with phase. Can you prove you can hear the phase? Especially below 100Hz? I turned phase pot left right, not sure about what position was better.
 
AIYIMA A03 Class D 2.1 Amplifier TPA3116D2 Bluetooth 5.0 2x50W + 100W 4 Ohm
I measured an older version of a similar amp some time ago, it was "AIYIMA TPA3116 Subwoofer Amplifier Board 2.1 Channel High Power Bluetooth 4.2 Audio Amplifier Board DC12V-24V 2*50W+100W".
the bass low-pass on that amp is 12 dB/octave (2nd order). it seems the output is inverted (180°) for correct integration.
the satellite high-pass is 1st order (6dB/oct),
there is a switch on the amp board that enables the stereo output to be high-passed or not (fullrange output to stereo speakers).

measurement was done with sat-high-pass enabled, treble on minimum, bass level medium, sat level maximum (only one channel was measured).
by the way: crossover frequency regulation only affects subwoofer-low pass frequency on my amp!
 

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Can you prove you can hear the phase?
Thank you for proposing solution. I am not in electronics so much, so do not like to build circuits myself. I am more in mechanical engineering.

The hearing of phase is totally another topic, plenty of them here as well. Mostly obsessed with timing and do not that much care if phase itself rotates gradually. But if timing at crossover is wrong, or messed up with higher order crossover, this you can not balance with summing the signals. The summed signal will be noise. Then it will be messed and stays so. I do not know about 100 Hz, but at 2000 Hz signal time difference already 0.05 ms can be heard when compared to 0.00 ms. Until the 0.00 is found, it all sounds pretty much the same, not matter how you position or delay your loudspeakers. If you find the real sweet spot there is amazing difference in sound quality.

So, it seems reasonable to use this simple 2.1 system to test the same principle on full range with subwoofer. There are some ways to do this expensively, but it is always reasonable to ask has anybody found simple solution to the problem. Can be that some sub amps do not have crossover, but just do not amplify higher frequencies? Or something similar, as said not at home with electronics - so just do not know.
 
I measured an older version of a similar amp some time ago
Thank you! This was the answer needed here and for the next one who has similar question. When looking at the phase and SP graphs it seems not so bad as I thought it could be. Phase is rotating on the same direction and can be set quite close on overlapping area until it drops out of hearable range. Should just choose some better model of these amps and give a try. As with sub it is plain simple position question to adjust timing later on.