Sub Not Recognizing Signal From Ultra

Emsflyer84

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Joined
Jan 18, 2026
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9
He all, I’ve got an RSL Speedwoofer connected to the sub-out on my Wiim. I’ve got the crossover in Wiim settings set to 80hz.

If I’m watching tv at lower volumes the sub doesn’t turn on. Even if I turn the volume up some, if I’m just watching something that’s mostly dialog, etc, the sub doesn’t turn on.

If I manually turn the sub on then flip the switch back to auto-on it will stay on, but won’t turn itself on in auto-on mode. It’s like there isn’t enough signal or the nothing is being passed to the sub below 80hz to trigger it to turn on.

Is this normal? Any ideas for a fix? Thanks!
 
Welcome.

What are your other settings in the subwoofer screen?
What about the subwoofer dials themselves? e.g. I'm assuming the sub itself has a crossover setting.
 
Hello, thanks for the reply. See photo for sub settings in app. Crossover knob on the sub is set around 100hz, but I figure it’s not getting any signal above 80hz from the Wiim anyway…. IMG_3780.png
 
Welcome.

What are your other settings in the subwoofer screen?
What about the subwoofer dials themselves? e.g. I'm assuming the sub itself has a crossover setting.
Just checked the sub, it’s turned itself off even though I’ve had my tv playing at moderate volume for a few hours. I turned it on manually and immediately heard bass coming from it so it’s definitely getting signal from the Wiim. Just not turning on.
 
Just checked the sub, it’s turned itself off even though I’ve had my tv playing at moderate volume for a few hours. I turned it on manually and immediately heard bass coming from it so it’s definitely getting signal from the Wiim. Just not turning on.
What is the volume level on the RSL Speed Woofer?

If the volume is set to 50% or higher, try lowering the RSL volume and instead increase the subwoofer level using the WiiM app.
 
What is the volume level on the RSL Speed Woofer?

If the volume is set to 50% or higher, try lowering the RSL volume and instead increase the subwoofer level using the WiiM app.
Sub is set at about 70%. I did try increasing the sub level in the Wiim app but the sub didn’t turn on.
 
Have you checked this with music or test tones that include low frequencies below 80Hz?

I think it's better to lower the Sub volume to 50%.
Will experiment with music or some known sub 80hz. Will also set sub to 50% volume and increase sub output in Wiim app.
 
Update, confirmed the sub did turn on right away streaming music, and with a different tv program (action movie). It must just be the sports broadcast I was watching that wasn’t triggering the sub to turn on.

Another strange observation. I ran the “audio sync” program to sync my speakers and my sub, and it seems like after I did that the output to my sub dropped off. I had my sub volume (on the sub itself) set at 50% and I had to turn the sub output on the Wiim app up all the way to get it to the level it was at previously.

Too many settings I probably messed something up without realizing. Lots of learning to do.
 
Update, confirmed the sub did turn on right away streaming music, and with a different tv program (action movie). It must just be the sports broadcast I was watching that wasn’t triggering the sub to turn on.
Yes, if the source contains only a small amount of bass, the subwoofer may not activate.

If you want to keep the subwoofer on at all times, you can also use a smart plug to control the power supply.



Another strange observation. I ran the “audio sync” program to sync my speakers and my sub, and it seems like after I did that the output to my sub dropped off. I had my sub volume (on the sub itself) set at 50% and I had to turn the sub output on the Wiim app up all the way to get it to the level it was at previously.

Too many settings I probably messed something up without realizing. Lots of learning to do.

That's strange.

I'm not sure why, but when synchronizing the speakers and subwoofer, you need to adjust it using "Subwoofer & Speakers Sync" within the sub settings, not "Audio Sync."
Audio Sync is for multi-room groups.

If the sub volume is too low, you might want to reset it to 70%. (If the sub activates at 70% with music sources, that's fine.)
 
I have the same issue with my REL HT1205 Mk2. My main speakers have 92 dB sensitivity, and my amp produces 240 W per channel. So I have to use very low total volume on the Wiim device

Increasing the subwoofer gain in the WiiM app should definitely help. You can go up to +10 or even more if needed. Just remember to deacrease the volume on the sub. You can also use a splitter cable before the signal reaches the sub – from both L/R channels. It also increases the max gain going to sub a bit
 
I have the same issue with my REL HT1205 Mk2. My main speakers have 92 dB sensitivity, and my amp produces 240 W per channel. So I have to use very low total volume on the Wiim device

Increasing the subwoofer gain in the WiiM app should definitely help. You can go up to +10 or even more if needed. Just remember to deacrease the volume on the sub. You can also use a splitter cable before the signal reaches the sub – from both L/R channels. It also increases the max gain going to sub a bit
This is probably my issue. My speakers are Klipsch Heresy IV’s with claimed 99db sensitivity. My amp is 150w / channel so my volume levels are almost always very low.
 
This is probably my issue. My speakers are Klipsch Heresy IV’s with claimed 99db sensitivity. My amp is 150w / channel so my volume levels are almost always very low.
Are you using a WiiM amp device or an external amp? In the latter case you try reducing the RCA output voltage. This way you‘d be running the WiiM at higher volume settings.
 
Crossover knob on the sub is set around 100hz, but I figure it’s not getting any signal above 80hz from the Wiim anyway….
You should also set the low pass crossover frequency knob on your sub to the BYPASS position and make sure to use the input labelled LFE.

This 80 Hz low pass filter in the Ultra is a steep 4th order LR filter, but it's not a brick wall filter. There is some content above 80 Hz coming through and this is also going to help. This is also the correct way of setting it up with high pass filtered speakers (which is the default setting and recommended). Make sure you have Subwoofer Bypass Mode and Main Speakers Output Bass disabled in the WiiM Ultra Subwoofer settings!

The syncing of subwoofers and speakers can have a slight effect on perceived loudness, but only in the region across the subwoofer frequency. Make also sure you tried both settings of the phase (just in the WiiM Home App, not on the sub). Whatever gives the louder sound is the right position to start with.
 
Are you using a WiiM amp device or an external amp? In the latter case you try reducing the RCA output voltage. This way you‘d be running the WiiM at higher volume settings.
I’m using the Wiim Ultra with a Parasound 2 channel power amp. Can the rca output voltage be reduced in the Wiim settings?
 
You should also set the low pass crossover frequency knob on your sub to the BYPASS position and make sure to use the input labelled LFE.

This 80 Hz low pass filter in the Ultra is a steep 4th order LR filter, but it's not a brick wall filter. There is some content above 80 Hz coming through and this is also going to help. This is also the correct way of setting it up with high pass filtered speakers (which is the default setting and recommended). Make sure you have Subwoofer Bypass Mode and Main Speakers Output Bass disabled in the WiiM Ultra Subwoofer settings!

The syncing of subwoofers and speakers can have a slight effect on perceived loudness, but only in the region across the subwoofer frequency. Make also sure you tried both settings of the phase (just in the WiiM Home App, not on the sub). Whatever gives the louder sound is the right position to start with.
Interesting. I am plugged into the LFE input in the sub but the crossover knob is not clicked in the LFF setting, it’s all the way up to 200hz. I figured that would effectively bypass the subs internal crossover and allows the Wiim bass management to override it.

You’re saying the sub should be set to LFE? I can try that.

Also, side note… is it reasonable to expect that I’ll have to keep the volume knob on the sub and th sub output settings in the Wiim turned up if my speakers are super efficient? Like the speaker volume is increasing much quicker then the sub volume when turning up the Wiim volume because of the efficiency of the speakers? Maybe turning down the RCA outputs like you said would help this. Right now I find I need to keep the volume knob on my sub around 70% and the sub output on the Wiim up to 10db for the sub to sound like it should. But the overall volume on the Wiim is never passing 30 because of the speaker efficiency.
 
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