WiiM Ultra active bass management w/ integrated amp

[Zantron]

Hi Everyone,
I’ve been enjoying dialling in my system with the WiiM Mini and RoomFit (the beta version's amazing) and have landed in a really good place. I’m now considering adding a WiiM Ultra, specifically for active bass management and would love to hear from anyone with experience of a similar setup.
Current setup:
• Streamer: WiiM Mini (optical out to Rotel)
• Amp: Rotel A14 MkII (80W/8Ω, 150W/4Ω Class AB)
• Speakers: Triangle Borea BR04 on stands (~7.5ft apart, ~9ft listening distance)
• Sub: Triangle Tales 340 (10”, 200W Class D, connected via RCA from Rotel pre-out)
• Source: Tidal Connect lossless/hi-res
• Room: ~3x4m opening into kitchen behind listening position
• RoomFit settings: Harman curve, Non-Boost Mode on, Moving Mic measurement, Psychoacoustic smoothing

The Rotel has no bass management so the BR04s receive a full range signal and the sub doubles up below 65Hz on top of the mains. Integration is decent but I believe a proper high-pass filter would be cleaner and should free up more headroom in the mids and highs. I'm hoping I can get a noticeable improvement in the listening experience.

I'm considering getting an Ultra and use its sub out for active bass management — high-pass to the Rotel line input, low-pass to the sub — at around 80Hz. Then rerun RoomFit with the new configuration.
Questions:

• Has anyone run this setup — Ultra into an integrated amp with active bass management? What crossover frequency worked best?
• Can the Ultra simultaneously output a high-passed digital signal (optical/coaxial) to use the Rotel’s DAC while the sub out handles the analogue low pass signal? Or does active bass management require using the Ultra’s analogue outputs for the mains? Do I need to use the WiiM Ultra DAC or can I use the Rotel's in this set up - and would there be a benefit to either?
• Any watch-outs with the Ultra’s bass management implementation before I dive in?

Really curious to get your thoughts and thanks for your input!
Thanks!

 

[Wiimer]

• Can the Ultra simultaneously output a high-passed digital signal (optical/coaxial) to use the Rotel’s DAC while the sub out handles the analogue low pass signal? Or does active bass management require using the Ultra’s analogue outputs for the mains? Do I need to use the WiiM Ultra DAC or can I use the Rotel's in this set up - and would there be a benefit to either?
• Any watch-outs with the Ultra’s bass management implementation before I dive in?

Hi,

I can only answer some of your questions, though...

The Ultra's crossover applies to both digital and analog outputs. Regardless of which connection method you choose, a high-pass signal will be sent to the amplifier. So please try all the outputs and choose the one that sounds best to you.

I think this goes without saying, but if you connect a subwoofer to the Ultra’s sub-out port, keep the amplifier’s volume fixed and adjust the volume on the Ultra. (E.g., Turning up the amplifier’s volume will not increase the subwoofer’s volume.)

The Mini doesn't support layering RoomFit and EQ. With the Ultra, you can use RoomFit profiles and EQ profiles simultaneously. You can use RoomFit to correct for your room and then use EQ to fine-tune the sound to your preference depending on the listening situation. Or, you can apply speaker correction filters to the EQ.

I hope this helps you make your decision.

 

[Wiimer]

There’s one more thing I forgot to mention that might be important to you: Ultra does not support AirPlay.

 

[Zantron]

Hi,

I can only answer some of your questions, though...

The Ultra's crossover applies to both digital and analog outputs. Regardless of which connection method you choose, a high-pass signal will be sent to the amplifier. So please try all the outputs and choose the one that sounds best to you.

I think this goes without saying, but if you connect a subwoofer to the Ultra’s sub-out port, keep the amplifier’s volume fixed and adjust the volume on the Ultra. (E.g., Turning up the amplifier’s volume will not increase the subwoofer’s volume.)

The Mini doesn't support layering RoomFit and EQ. With the Ultra, you can use RoomFit profiles and EQ profiles simultaneously. You can use RoomFit to correct for your room and then use EQ to fine-tune the sound to your preference depending on the listening situation. Or, you can apply speaker correction filters to the EQ.

I hope this helps you make your decision.

Thanks so much, really helpful! Two follow-up questions if you don’t mind.
On the DAC — given the high-pass filter applies to both digital and analogue outputs, does the digital output use the amplifier’s DAC, or does the Ultra’s own DAC perform well enough that the analogue output is preferable? Any community feedback on this?

Any feedback from users with a similar setup report meaningful improvements in sound quality after switching to active bass management with the Ultra? Particularly in terms of midrange clarity and overall integration?
Thanks again!

 

[DazST]

I'm not familiar with the Rotel (or the quality of its dac) but I have run a similar setup with a Yamaha integrated amp and there was a definite improvement using the ultra for bass management. Being able to high pass mains and tinker with cross over frequency based on your speakers and room shouldn't be underestimated if you're interested in maximising your system's capabilities. With my speakers (Q Acoustics 3030i) I ended up settling on a 70hz crossover.
In relation to your dac questions, yes a digital connection will use the amplifier's dac rather than the WiiM. I personally find the WiiM dac to be perfectly capable, but you can always use both rca and digital connections and see which you prefer.

 

[Zantron]

Super helpful and informative — definitely feels like a no-brainer at this price point given everything it offers.
One more wrinkle, have you tried to integrate a turntable into a similar setup?
I’m planning to add a Rega P3 at some point and have two options. Route it through the Rotel’s built-in MM phono stage which is a quality implementation but takes the signal outside the Ultra entirely, losing active bass management for vinyl. Or use the Ultra’s built-in MM phono stage which keeps everything consistent — bass management and RoomFit applying to vinyl too — but potentially at some cost to phono stage quality compared to the dedicated Rotel stage.
How’s the Ultra’s MM phono stage against a decent integrated amp phono stage? And does active bass management make a meaningful enough difference to justify routing vinyl through the Ultra rather than a better dedicated stage?

 

[DazST]

Super helpful and informative — definitely feels like a no-brainer at this price point given everything it offers

Yeah I honestly consider the Ultra to be one of the biggest "no brainers" in audio today when you consider it's features, versatility quality and cost.
Unfortunately I don't use vinyl so can't help with that aspect, though I'm sure others with that knowledge will chip in.

 

[Wiimer]

or does the Ultra’s own DAC perform well enough that the analogue output is preferable? Any community feedback on this?

I think it’s best to start by trying an analog connection to check the sound quality of the Ultra’s DAC. You might want to compare the Ultra’s digital filters.

Seven DAC Digital Filter Types

The WiiM Ultra is powered by the high-performance ESS ES9038Q2M DAC, delivering exceptional audio clarity and ultra-low distortion. To further fine-tune the Line Out and Headphone Out audio output, the DAC provides seven digital filter typ...

faq.wiimhome.com

Opinions vary on whether analog or digital is better. Some people prefer USB out. Since everyone uses different systems, I think you’ll just have to try them out for yourself.

Since the Rotel A14 MkII has a line input sensitivity of 230 mV, I recommend you try setting the Ultra's line-out level to 500 mV.

 

[hipoagumol]

Since the Rotel A14 MkII has a line input sensitivity of 230 mV, I recommend you try setting the Ultra's line-out level to 500 mV.

Why?
Input sensitivity in the amp indicates the minimum input signal level so as the amp can still provide its maximum rated power with the volume potentiometer to its maximum.
This modern Rotel amp , and all modern amps, can perfectly work with 2Vrms inputs from Ultra and that is actually the recommended setting if you want to maximize the SNR.
Setting the ultra's output analog output so low you'll lower the snr you can get out of your amplifier ans will need to turn up volume on rotel so much to get reasonable listening levels.

 

[slartibartfast]

Why?
Input sensitivity in the amp indicates the minimum input signal level so as the amp can still provide its maximum rated power with the volume potentiometer to its maximum.

So if the input voltage is 2V and the input sensitivity is 230mV maximum volume will be reached at the low end of the volume control and the usable range will be below that. If you want to use more of the volume control rotation you need to reduce the output voltage.

 

[harkpabst]

Why?
Input sensitivity in the amp indicates the minimum input signal level so as the amp can still provide its maximum rated power with the volume potentiometer to its maximum.
This modern Rotel amp , and all modern amps, can perfectly work with 2Vrms inputs from Ultra and that is actually the recommended setting if you want to maximize the SNR.
Setting the ultra's output analog output so low you'll lower the snr you can get out of your amplifier ans will need to turn up volume on rotel so much to get reasonable listening levels.

I wouldn't give this strategy a strict recommendation, it really depends.

First off, you are right to differentiate the input sensitivity from the overload margin. A 2 V signal might or might not overload the input stage. I didn't try to look up the specs of the A 14 Mk II, but most manufacturers are unfortunately tight-lipped about overload margins. Any input labelled CD will always take 2 V without problems, that's for sure. There is still a risk of driving the power stage into clipping by accident.

But there's one more point. Depending on the exact design of the amplifier, a 2 V source might actually be attenuated by the pre-amplifier stage (including the volume pot) before feeding it to the power stage. The result is exactly the same as setting a lower output voltage on the streamer: reduced SNR. Plus you might be operating the potentiometer in its lower range for normal listening levels, potentially resulting in higher channel imbalance and higher noise and distortion.

Admittedly, I don't know how the A 14 Mk II is constructed. Still I think that an output voltage of 500 mV is a very good starting point for an amp with an input sensitivity of 230 mV.

 

[hipoagumol]

Hello again
The context this thread we are assuming that volume control will take place in ultra (sub out and mains), so the point is not maximize the amp volume knob volume usable range...but to fix it to a position that allows controlling volume with Ultra while maximizing snr and avoiding analog and digital clipping.
In that case isn't this below procedure a best practice ?:

1) Set Ultra's Line Out level to 2Vrms. As mentioned all cd input/aux inputs in modern amps will perfectly cope with that signal levels and produce no clipping at normal listening levels. Actually that Rotel Overload input level is 4Volts!
https://www.rotel.com/manuals/a14mkii_om_en.pdf

2) Create enough volume headroom on Wiim Ultra to avoid digital clipping by adjusting pre-gain o volume limit so as you compensate the total Gain in dB introduced by the different DSP functions and DAC
- Roomfit (only if boost allowed)
- PEQ or band/preset EQ (most of presets don't go beyond +5dB)
- And maybe 2-3dB extra for DAC'S output ISP.

Let's say the above sums up 8dB.
We must create in Wiim Ultra enough headroom so as the digital signal before Roomfit-PEQ/EQ-DAC does not exceed -8dBFS. That we can achieve for example setting Volume Limit to limit let's say to 80% (not sure how 80% maps to dB, lets assume this 80% means -8dB). Alternatively we can set all digital inputs pre gains to -8dB. Then a song that reaches 0dBFs signal at some freqs will instead reach -8dBFS and after going through adding our roomfit/EQ and DAC ISP will be 0dBFS / 2Volts analog and we will be safe on the digital domain and providing a healthy signal to our amp (which will not cause overload)

3) Set the ultra volume control at 100% and the Amp volume control to 0% and start playing some loud music
4) Turn up the Amp's volume knob until you reach the max sound pressure you'll ever need in your room.
5) Remember or mark that amp's knob position and keep it forever
6) now just always control volume with the wiim ultra remote or wiim home app

Hopefully in steps 4-5 you'll end in an amp knob position that isn't too low and causes the imbalance or noise problems mentioned by harkpabst...if you feel/hear such problems but still want to keep the headroom margin on the Wiim then yes, lower the Line Output to 1V instead (i think they are adding 1.5V option also soon)

On the other hand if we provide a max 500mV signal to the amp it means our digital signal peaks 0dBFS will be 500mV but most of the calm passages music , let's say around-10/-12dBFS will be output as 125mV, well below the amp sensitivity! meaning we will have a really poor SNR and will need to turn up a lot the amp knob.

As far as I know using low input voltage only makes sense for vintage 60s-70s Amps (before CD era) which will saturate with 2v, 1v or even 500mv signal levels.

Am i wrong? The above is the result of learning by reading different forums (here and ASR) and with some AI help too... And it made perfect technical sense for my engineer mind.... but there might be a flaw in the analysis.
I used that and that worked perfectly in my setup (ultra connected via analog to yamaha a-s501).

 

[Burnside]

It's been noted that each 5% of the limiter has 3 dB attenuation. Also this post suggests using REW to calculate the headroom needed when you use PEQ - it'd be useful if the WiiM app could do the calculations for you rather than having to manually enter the settings into another app.

Post in thread 'PEQ talk'
https://forum.wiimhome.com/threads/peq-talk.1500/post-27059

 

[Zantron]

Hello again
The context this thread we are assuming that volume control will take place in ultra (sub out and mains), so the point is not maximize the amp volume knob volume usable range...but to fix it to a position that allows controlling volume with Ultra while maximizing snr and avoiding analog and digital clipping.
In that case isn't this below procedure a best practice ?:

1) Set Ultra's Line Out level to 2Vrms. As mentioned all cd input/aux inputs in modern amps will perfectly cope with that signal levels and produce no clipping at normal listening levels. Actually that Rotel Overload input level is 4Volts!
https://www.rotel.com/manuals/a14mkii_om_en.pdf

2) Create enough volume headroom on Wiim Ultra to avoid digital clipping by adjusting pre-gain o volume limit so as you compensate the total Gain in dB introduced by the different DSP functions and DAC
- Roomfit (only if boost allowed)
- PEQ or band/preset EQ (most of presets don't go beyond +5dB)
- And maybe 2-3dB extra for DAC'S output ISP.

Let's say the above sums up 8dB.
We must create in Wiim Ultra enough headroom so as the digital signal before Roomfit-PEQ/EQ-DAC does not exceed -8dBFS. That we can achieve for example setting Volume Limit to limit let's say to 80% (not sure how 80% maps to dB, lets assume this 80% means -8dB). Alternatively we can set all digital inputs pre gains to -8dB. Then a song that reaches 0dBFs signal at some freqs will instead reach -8dBFS and after going through adding our roomfit/EQ and DAC ISP will be 0dBFS / 2Volts analog and we will be safe on the digital domain and providing a healthy signal to our amp (which will not cause overload)

3) Set the ultra volume control at 100% and the Amp volume control to 0% and start playing some loud music
4) Turn up the Amp's volume knob until you reach the max sound pressure you'll ever need in your room.
5) Remember or mark that amp's knob position and keep it forever
6) now just always control volume with the wiim ultra remote or wiim home app

Hopefully in steps 4-5 you'll end in an amp knob position that isn't too low and causes the imbalance or noise problems mentioned by harkpabst...if you feel/hear such problems but still want to keep the headroom margin on the Wiim then yes, lower the Line Output to 1V instead (i think they are adding 1.5V option also soon)

On the other hand if we provide a max 500mV signal to the amp it means our digital signal peaks 0dBFS will be 500mV but most of the calm passages music , let's say around-10/-12dBFS will be output as 125mV, well below the amp sensitivity! meaning we will have a really poor SNR and will need to turn up a lot the amp knob.

As far as I know using low input voltage only makes sense for vintage 60s-70s Amps (before CD era) which will saturate with 2v, 1v or even 500mv signal levels.

Am i wrong? The above is the result of learning by reading different forums (here and ASR) and with some AI help too... And it made perfect technical sense for my engineer mind.... but there might be a flaw in the analysis.
I used that and that worked perfectly in my setup (ultra connected via analog to yamaha a-s501).

This is great - way more insight than I expected! I had not even considered any of these factors when researching the setup. Hugely helpful - thank you!

 

[canard]

It's been noted that each 5% of the limiter has 3 dB attenuation. Also this post suggests using REW to calculate the headroom needed when you use PEQ - it'd be useful if the WiiM app could do the calculations for you rather than having to manually enter the settings into another app.

Post in thread 'PEQ talk'
https://forum.wiimhome.com/threads/peq-talk.1500/post-27059

GEC, presets GEC, PEQ, presets PEQ, roomfit, roomfit+peq/gec ( aie)...




(Impact of pregain positif?)

 

[Zantron]

Really helpful input, everyone! Thank you.

Ultimately, my goal of the upgrade
is to take full advantage of the RoomFit - the new continuous measurement feature has already made a huge difference with my I’m Mini (though I suppose it’s the same result on the Iltea) combined with the active bass management for better sub integration to get the most out of my 2.1.

 

[harkpabst]

I currently don't have the time (nor access to my computer) to answer in full detail. For now I just want to note that steps 3 and 4 ...

3) Set the ultra volume control at 100% and the Amp volume control to 0% and start playing some loud music
4) Turn up the Amp's volume knob until you reach the max sound pressure you'll ever need in your room.

... have nothing to do with optimising the gain structure or maximising SNR. They only serve as a safety net for those who are afraid of digital volume control failing and fear that their power amp might kill their speakers ... and their hearing.

Generally speaking and slightly simplified it's always gain that adds noise to the signal, not (analogue) attenuation. But ideally you don't want to attenuate a signal unnecessarily, so it needs gain in the next stage, even if it was strong enough initially.

Reducing the Ultra's maximum output voltage does not reduce digital resolution, it's performed in the analogue domain.

 

[rjp]

Hello again
The context this thread we are assuming that volume control will take place in ultra (sub out and mains), so the point is not maximize the amp volume knob volume usable range...but to fix it to a position that allows controlling volume with Ultra while maximizing snr and avoiding analog and digital clipping.
In that case isn't this below procedure a best practice ?:

1) Set Ultra's Line Out level to 2Vrms. As mentioned all cd input/aux inputs in modern amps will perfectly cope with that signal levels and produce no clipping at normal listening levels. Actually that Rotel Overload input level is 4Volts!
https://www.rotel.com/manuals/a14mkii_om_en.pdf

2) Create enough volume headroom on Wiim Ultra to avoid digital clipping by adjusting pre-gain o volume limit so as you compensate the total Gain in dB introduced by the different DSP functions and DAC
- Roomfit (only if boost allowed)
- PEQ or band/preset EQ (most of presets don't go beyond +5dB)
- And maybe 2-3dB extra for DAC'S output ISP.

Let's say the above sums up 8dB.
We must create in Wiim Ultra enough headroom so as the digital signal before Roomfit-PEQ/EQ-DAC does not exceed -8dBFS. That we can achieve for example setting Volume Limit to limit let's say to 80% (not sure how 80% maps to dB, lets assume this 80% means -8dB). Alternatively we can set all digital inputs pre gains to -8dB. Then a song that reaches 0dBFs signal at some freqs will instead reach -8dBFS and after going through adding our roomfit/EQ and DAC ISP will be 0dBFS / 2Volts analog and we will be safe on the digital domain and providing a healthy signal to our amp (which will not cause overload)

3) Set the ultra volume control at 100% and the Amp volume control to 0% and start playing some loud music
4) Turn up the Amp's volume knob until you reach the max sound pressure you'll ever need in your room.
5) Remember or mark that amp's knob position and keep it forever
6) now just always control volume with the wiim ultra remote or wiim home app

Hopefully in steps 4-5 you'll end in an amp knob position that isn't too low and causes the imbalance or noise problems mentioned by harkpabst...if you feel/hear such problems but still want to keep the headroom margin on the Wiim then yes, lower the Line Output to 1V instead (i think they are adding 1.5V option also soon)

On the other hand if we provide a max 500mV signal to the amp it means our digital signal peaks 0dBFS will be 500mV but most of the calm passages music , let's say around-10/-12dBFS will be output as 125mV, well below the amp sensitivity! meaning we will have a really poor SNR and will need to turn up a lot the amp knob.

As far as I know using low input voltage only makes sense for vintage 60s-70s Amps (before CD era) which will saturate with 2v, 1v or even 500mv signal levels.

Am i wrong? The above is the result of learning by reading different forums (here and ASR) and with some AI help too... And it made perfect technical sense for my engineer mind.... but there might be a flaw in the analysis.
I used that and that worked perfectly in my setup (ultra connected via analog to yamaha a-s501).

So you're saying the WiiM Ultra's roomfit and EQ sections are potentially boosting the output signal beyond the full scale 2vrms limits and causing distortion? It would be nice if WiiM compensated for any of these custom gains to keep the output constant.
I didn't realize that boosting an EQ band could be clipping the output. Makes sense though if there is no automatic leveling.

 

[canard]

But this obvious fact, a corollary associated with all DSP manipulations, etc., has existed for four years...
I invite you to observe the different presets of the GEC mode (which arrived with GEC mode in spring 2022) and imagine the impact without readjusting the gain... etc. *

In the absence of auto-gain, we know that a simple manual gain adjustment, particularly in negative mode on GEC, PEC, PEQ presets, etc., could already make a big difference...

The DRC at 0dB isn't inherently negative, but in our case, it doesn't allow for accurate observation of what's happening with saturation due to excessive gain...He simply shouldn't intervene if the situation was healthy...

An on/off switch for drc would therefore be useful... and ideally, an overload indicator would allow us to adjust our gains more judiciously...


How tiresome it is to repeat this over the years... and to come across as an idiot, to "ramble"...
when, in the end, the problem isn't mine. That's the point, but this obvious technical problem isn't being addressed...



This is where Wiim comes across as ill-advised in the field of audio, given how obvious the subject is....
4 years...

(*I know this because... I was in direct contact with their technicians on the first day of its release to inform them of this... with supporting saturation measurements... which they had to acknowledge. The forum did not yet exist, and only the "mini" existed.)

 

[rjp]

Hmm, pretty sure when I had Roon it had an auto-level option for EQ. Maybe it was elsewhere. EQ devices used to have overall gain sliders to compensate for this in the old days. I just thought (hoped) that given how advanced the WiiM Ultra seems to be in so many ways they would have had the good sense to auto compensate any filter gains. Seems so easy to implement. Glad you tried to talk some sense into them.