WiiM Ultra

[Mort]

Set the Crossover frequency to 60Hz in the App, then disconnect the speaker amp and subwoofer from the Ultra and play a 60Hz sine tone on loop (file attached below).

Probe the Main and Sub outputs with your multimeter set to V AC and note down the voltages of each, at different volumes.
View attachment 390553

Make a spreadsheet like this;

Volume​	Main Out [Vrms]​	Sub out [Vrms]​	Volume difference [20*log10(Main out/Sub out)] [dB]​
100​	2.03​	1.01​	6.03​
73​	1.37​	0.68​	6.03​
28​	0.23​	0.11​	6.03​

If the volume offset between Main and Sub out is consistent across multiple volumes, then your issue lies elsewhere.


You set the volume offset once in the App to account for the difference in sensitivity between Sub and Mains, and then the Ultra just preserves that offset no matter how loud or quiet you listen.

It's really quite foolproof.

And the 'elsewhere' could be
1) room modes
2) human misperception

What else?

 

[Soniclife]

If you have both sub level adjustment in Ultra AND a gain control in the sub, which is the best approach to use? Set the sub to a lower volume, and then run your RC etc and make adjustments to sub level in the app, or whack the sub amp up and run it again that way? I'm presuming that so long as there is enough headroom in Ultra and likewise in the sub's amp it doesn't really matter...

Higher gain from the ultra and lower gain in the sub might be lower noise, but if there is no noise with any setting it doesn't matter.

 

[Deleted member 71304]

would it be possible to use a wiim mini connected directly to the sub and a low pass filter set with PEQ? If this is synchronized with the wiim device driving the mains it might be an option...

 

[Burnside]

would it be possible to use a wiim mini connected directly to the sub and a low pass filter set with PEQ? If this is synchronized with the wiim device driving the mains it might be an option...

Your playback resolution would be limited to 24/48 though as that’s currently the limit for linkplay groups.

 

[staticV3]

And the 'elsewhere' could be
1) room modes
2) human misperception

What else?

Maybe a faulty sub?

Anyway, speculating without data doesn't get us anywhere.

 

[Dennis_FL]

I have similar, but different solution.

I use the Ultra for my speakers, and my old Mini into headphone amp/DAC for precisely the reasons you’ve given. As I had the Mini and headphone amp/DAC already, it’s cost me nothing.

The Fosi doesn’t have the bass management of the Ultra, that’s a big step backwards.

When I did the Room correction, my sub (auto on) wasn't turning on and there was an overcorrection of the bass. I had suspected the sub out wasn't working right when I was using an external DAC so I asked on the WiiM Support forum and got this reply.

Currently, the USB out cannot use the Sub out. With the Sub out turned on, the USB out will not be highpassed and will be full range. Therefore, the sub out should be turned off.

So the Sub option should be greyed out in the APP but it isn't.

 

[Dennis_FL]

I'm impressed with the subwoofer management capabilities of the ultra. Setting the crossover accurately for 2.1 desktop is essential.

I'm very disappointed the sub can't be assigned to a single output. It runs when I switch to headphones, which requires me to have my svs remote handy. Not so handy.

I'm probably more disappointed that I don't think the sub scales volume properly with the stereo signal. I have to increase volume on the sub as I increase. It's fine for most listening, assuming few dynamic swings.

I love the ultra but sub management is meaningfully incomplete. Hopefully this is addressed with software.

Yeah....the sub comes on with headphones and doesn't come on with USB out to a DAC. WiiM has many, many firmware updates as they seem to overlook a lot.

 

[Dennis_FL]

If you have both sub level adjustment in Ultra AND a gain control in the sub, which is the best approach to use? Set the sub to a lower volume, and then run your RC etc and make adjustments to sub level in the app, or whack the sub amp up and run it again that way? I'm presuming that so long as there is enough headroom in Ultra and likewise in the sub's amp it doesn't really matter...

There is a Stereo Test recording on Roon that I use and have the Sub crossover set at 80dB. It plays a sub frequency below 80Hz and then a higher frequency for the Mains in a loop. I have a dB meter and I adjust the mains for 75dB and then adjust the sub for the same.

 

[Burnside]

Yeah....the sub comes on with headphones and doesn't come on with USB out to a DAC. WiiM has many, many firmware updates as they seem to overlook a lot.

Have you raised tickets to bring these issues to WiiM’s attention? The more who do, the better chance of them being resolved.

 

[somebodyelse]

Yeah....the sub comes on with headphones and doesn't come on with USB out to a DAC. WiiM has many, many firmware updates as they seem to overlook a lot.

Following the 'minimum viable product' approach when introducing new hardware, they launched with the most commonly used features implemented. New capabilities are added and existing ones improved with each firmware and/or app update - at least if we ignore the Apple issues.

 

[Deleted member 71304]

Leaving aside these issues, would it be accurate to state that the Ultra's crossover works reasonably well?
If not, which would be the alternative?

 

[somebodyelse]

Leaving aside these issues, would it be accurate to state that the Ultra's crossover works reasonably well?
If not, which would be the alternative?

It's not bad now, and will probably gain capabilities in future like differing filter orders to cope with sealed vs. ported speakers. If you need something more versatile now you're probably looking at AVRs, MiniDSP or something from the Pro world. Or rolling your own with an audio interface and some software like CamillaDSP.

 

[Dennis_FL]

Have you raised tickets to bring these issues to WiiM’s attention? The more who do, the better chance of them being resolved.

Many have....here's the response

Currently the USB Out does not allow sub, but the WiiM team says they are looking into whether this is possible.

I think the sub is allowed with other digital outputs. I may try an optical or coax output to my DAC and see if it works. I doubt if the Ultra internal DAC is creating an analog filter for the other digital outputs but I'll try.

 

[Mort]

Subwoofer output works with toslink and coaxial for sure. Problem there is you can't turn it off. Unfortunately, one can not remove the sub from individual channels (like my headphone stack).

Since the subwoofer is active and being crossed at 80, does that imply the headphones downstream are not reproducing below 80 either? How low do headphones go? Does that matter?

 

[Dennis_FL]

Subwoofer output works with toslink and coaxial for sure. Problem there is you can't turn it off. Unfortunately, one can not remove the sub from individual channels (like my headphone stack).

Since the subwoofer is active and being crossed at 80, does that imply the headphones downstream are not reproducing below 80 either? How low do headphones go? Does that matter?

I suspect the external headphone amp is getting only 80-20k and not the full range.

 

[Dennis_FL]

Subwoofer output works with toslink and coaxial for sure. Problem there is you can't turn it off. Unfortunately, one can not remove the sub from individual channels (like my headphone stack).

Since the subwoofer is active and being crossed at 80, does that imply the headphones downstream are not reproducing below 80 either? How low do headphones go? Does that matter?

As a temporary solution, I have the sub coming from my Fosi amp …. It has a filtered output of 20-300 hz. The mains aren’t filtered and get full range.

I have the better option of having the sub do bass control but then I lose balanced output to my amp and nowhere to hook up my headphone amp.

 

[Bernard23]

How are you handling latency? Separating sub from mains DSP is always going to be challenging. I suppose you could sell your Gustard, but that's not being very helpful....

 

[Dennis_FL]

How are you handling latency? Separating sub from mains DSP is always going to be challenging. I suppose you could sell your Gustard, but that's not being very helpful....

Gustard DAC unbalanced RCAs out would go to the sub in and the sub out would go to the amp in

 

[Deleted member 71304]

Apollogies if my question is a bit out of topic but I just ordered an Ultra+Subwoofer and would like to ask if a standard rca cable can be used for LFE.
And a coaxial?
if none of the above... would u recommend a mogami or inakustik subwoofer cable?
Thank you so much in advance!

 

[Dennis_FL]

Apollogies if my question is a bit out of topic but I just ordered an Ultra+Subwoofer and would like to ask if a standard rca cable can be used for LFE.
And a coaxial?
if none of the above... would u recommend a mogami or inakustik subwoofer cable?
Thank you so much in advance!

Yes…RCA cable…for the sub

Not sure what you are asking with coax? There is a digital coax out but it’s not for the sub.