How to connect a passive subwoofer to WiiM amp ultra using the Fosi TP-02 Sub Amp?

[Riders343]

Hello,

I wish to connect a passive subwoofer (Episode® ES-SUB-IW-SNGL8) to WiiM amp ultra using the Fosi TP-02 Sub Amp. Can you advise on how the TP-02 connects to the WiiM Amp Ultra?

*I will also be connecting two speakers (8 ohm impedance) as my front L/R.









Subwoofer


Speakers (x2)


My glass is way over half full.

 

[Riders343]

Note: Subwoofer is 4 ohm nominal impedance. Any issues driving it along with the 2 8 ohm fl & fr speakers?

 

[harkpabst]

Note: Subwoofer is 4 ohm nominal impedance. Any issues driving it along with the 2 8 ohm fl & fr speakers?

No need to worry, they don't interfere with each other at all. The WiiM Amp Ultra can drive even low impedance speakers and it doesn't "see" the passive subwoofer at all.

I wish to connect a passive subwoofer (Episode® ES-SUB-IW-SNGL8) to WiiM amp ultra using the Fosi TP-02 Sub Amp.

Did you already buy these components? The TP-02 is not the ideal amplifier for your setup, because it implements its own low pass filter. This low pass filter is not needed (the WiiM Ultra provides low pass filtering for the subwoofer and matching high pass filtering for the main speakers) and it will potentially negatively affect a smooth transition from the sub to the mains.

Unfortunately, Fosi provide conflicting information about the adjustable frequency range for the sub. Sometimes they say 20 Hz to 200 Hz, sometimes it's 20 Hz to 120 Hz. An upper frequency of 200 Hz might be barely acceptable if you plan to cross the subwoofer at 80 Hz or lower. 120 Hz would be really bad. In any case it is advisable to set the SUB FREQ knob fully clockwise.

I don't have a personal recommendation, but amplifiers like the Nobsound G2 PRO or the AIYIMA A3001 allow to switch off the low pass filter and put the amps into a "flat frequency response" mode, which is much better suited to the WiiM Ultra.

No matter which of the mono amps you choose, the procedure is always the same:

• Set the frequency response to flat or the LP frequency to maximum, set the volume knob to ~50% or slightly higher
• Connect the plus and minus speaker outputs to the plus and minus inputs of the subwoofer using large cross-section cable
• Connect the single subwoofer output of the WiiM Ultra to either the left or the right input of the mono amp, it doesn't matter which one. If you want to you can use a y-splitter cable and connect the single subwoofer output bot both inputs simultaneously, but there's absolutely no need to.
• Connect the external power supply and switch on the mono amp and the WiiM Ultra
• Use the WiiM Home App to enable the Sub Out on the WiiM Ultra

From here on you'll have to setup the subwoofer just like any powered active sub by setting the level, the crossover frequency, the phase switch and syncing subwoofer and speakers.

 

[Mr Ee]

@Riders343
Just to be clear, you wrote Amp Ultra but posted pictures of the Ultra. They are different items, which did you mean?

 

[Riders343]

@Riders343
Just to be clear, you wrote Amp Ultra but posted pictures of the Ultra. They are different items, which did you mean?

Good eyes. I did mean the Amp Ultra but screen grabbed the wrong pic.

No need to worry, they don't interfere with each other at all. The WiiM Amp Ultra can drive even low impedance speakers and it doesn't "see" the passive subwoofer at all.


Did you already buy these components? The TP-02 is not the ideal amplifier for your setup, because it implements its own low pass filter. This low pass filter is not needed (the WiiM Ultra provides low pass filtering for the subwoofer and matching high pass filtering for the main speakers) and it will potentially negatively affect a smooth transition from the sub to the mains.

Unfortunately, Fosi provide conflicting information about the adjustable frequency range for the sub. Sometimes they say 20 Hz to 200 Hz, sometimes it's 20 Hz to 120 Hz. An upper frequency of 200 Hz might be barely acceptable if you plan to cross the subwoofer at 80 Hz or lower. 120 Hz would be really bad. In any case it is advisable to set the SUB FREQ knob fully clockwise.

I don't have a personal recommendation, but amplifiers like the Nobsound G2 PRO or the AIYIMA A3001 allow to switch off the low pass filter and put the amps into a "flat frequency response" mode, which is much better suited to the WiiM Ultra.

No matter which of the mono amps you choose, the procedure is always the same:

• Set the frequency response to flat or the LP frequency to maximum, set the volume knob to ~50% or slightly higher
• Connect the plus and minus speaker outputs to the plus and minus inputs of the subwoofer using large cross-section cable
• Connect the single subwoofer output of the WiiM Ultra to either the left or the right input of the mono amp, it doesn't matter which one. If you want to you can use a y-splitter cable and connect the single subwoofer output bot both inputs simultaneously, but there's absolutely no need to.
• Connect the external power supply and switch on the mono amp and the WiiM Ultra
• Use the WiiM Home App to enable the Sub Out on the WiiM Ultra

From here on you'll have to setup the subwoofer just like any powered active sub by setting the level, the crossover frequency, the phase switch and syncing subwoofer and speakers.

Thanks for the info. Much appreciated. I read somewhere (maybe on this board?) about the Fosi TP-02 being recommended to drive a passive sub off the Amp Ultra but should have vetted that before buying. Hope I won’t have issues returning it.

 

[Mr Ee]

Assuming you got the right pics for the Fosi (), it takes dual rca input.
The amp ultra doesn't have dual rca output, although I suppose you could use a single to dual rca cable.