Can wiim do the following? High and low passing

[alaios]

So pick the most advanced wiim device and then help me understand if the below are possible.

Can i high pass my main speakers and relieve them from having to try to go too low?
Then can I high pass (yes high pass) my sub (sub out) as these are smallish and do not got really below 40Hz. I would like also to relieve them of having to try to play 30 or 20Hz.

Are such things possible with wiim ? If yes where I can read before buying the guides/tutorials

Regards,
Alex

 

[slartibartfast]

what is a high shelf filter

All you need to know is in post #24. You have read that haven't you?

 

[alaios]

I should have quoted only this part to make it perfectly clear. So, let's try again.

Yes, exactly. That's how it works.

When you enable the subwoofer output (available on WiiM Ultra, WiiM AMP Pro and WiiM Amp) you find a crossover frequency slider like so:
View attachment 17591

You can freely set the crossover frequency between mains and sub from 30 Hz to 250 Hz. No matter which value you choose, the result will always be both, a 4th order Linkwitz-Riley low pass for the sub and a matching 4th order LR high pass filter for the mains.

This is ideal if you have small main speakers or full range speakers. If set to e.g. 80 Hz, the your mains level will be down by 6 dB at 80 Hz. Below 80 Hz the level is reduced at a slope of 24 dB per octave.


Correct again. With no additional PEQ applied the sub will get all the frequencies below e.g. 80 Hz. More precisely, the sub level will be down by 6 dB at 80 Hz and higher frequcies are attenuated by 24 dB per octave.

When combined, the frequency response of mains and sub is perfectly flat again.

I understand that you not only want to relieve your main speakers from the low frequcies fed to the subwoofer. You also want to make sure your small sub doesn't have to cope with the lowest frequencies, which it cannot reproduce anyway, but just cause distortion. And yes, another high pass filter at 30 to 40 Hz would be the natural choice here.

WiiM PEQ cannot exactly do that, but it can do something that serves the same purpose. While PEQ filters cannot be of type "high pass", you can e.g. employ a low shelf filter like this:
View attachment 17594

The result is not a true high pass filter, but it will dramatically reduce the low frequcies fed into the subwoofer. If you want even more attenuation, just add one more low shelf filter, e.g. like this:
View attachment 17595

This will be as effective as a high pass filter

@Wiimer has shown an alternative approach in posting #5 using just peak filters. This will also work.

Is this more clear?

So what you say is that there is the PEQ filters and at the same time the crossover frequency. It is the crossover frequency that will high pass the main speakers and not the PEQ. So in the example above there are two "filters" running in parallel. The crossover and the PEQ that you drew here.

I guess both are applied in the digital domain so I can use the wiim ultra just as cheap dsp unit and feed it digital output to the preamp of my preference.

 

[harkpabst]

So what you say is that there is the PEQ filters and at the same time the crossover frequency. It is the crossover frequency that will high pass the main speakers and not the PEQ. So in the example above there are two "filters" running in parallel. The crossover and the PEQ that you drew here.

I guess both are applied in the digital domain so I can use the wiim ultra just as cheap dsp unit and feed it digital output to the preamp of my preference.

Yes and yes.

 

[hgo58]

So what you say is that there is the PEQ filters and at the same time the crossover frequency. It is the crossover frequency that will high pass the main speakers and not the PEQ. So in the example above there are two "filters" running in parallel. The crossover and the PEQ that you drew here.

Yes. Multiple filters to handle multiple requests. You cannot say that they run in parallel. They are just all applied to the same digital data stream.

I guess both are applied in the digital domain so I can use the wiim ultra just as cheap dsp unit

The WiiM Ultra has a good DSP but it's primarily a streaming pre-amp.

and feed it digital output to the preamp of my preference.

No. Not to a pre-amp. Only to a power amplifier, as else you will have issues controlling the subwoofer volume in sync with the main speakers.

 

[alaios]

Yes and yes.

great. I was trying to understand that "algorithm". From the online manual it was not clear at all
Have you confirmed the above with measurements at your speakers right

 

[alaios]

Yes. Multiple filters to handle multiple requests. You cannot say that they run in parallel. They just all work on the same digital data.

The WiiM Ultra has a good DSP but it's primarily a streaming pre-amp.

No. Not to pre-amp. Only to the power amplifier, as else you will have issues controlling the subwoofer volume in sync with the main speakers.

Good to hear about the DSP.
Related to the pre-amp you are right. I should be using the wiim ultra for
1. source selection
2. Type of dsp device (all the discussion above)
3. volume control.

then I need to buy power amplifier for my main speakers. Mission accomplished

 

[harkpabst]

Good to hear about the DSP.
Related to the pre-amp you are right. I should be using the wiim ultra for
1. source selection
2. Type of dsp device (all the discussion above)
3. volume control.

then I need to buy power amplifier for my main speakers. Mission accomplished

No problem then. I had initially missed the term "preamp" and indeed you must be controlling the volume of mains and sub on the WiiM Ultra to keep the balance between them matched. A power amp is all you need.

Nowadays many small power amps do come with an additional volume control (mostly for desktop use). In this case you will have to keep this volume control always at the same level (e.g. fully clockwise), because again a volume control on the power amp won't control the subwoofer.