Initial calibration

Solus47

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Joined
Aug 5, 2024
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I blasted through my initial setup not really understanding some of the setting within the WiiM App.

Anyway, I had some great advice from you guy and I’ve swapped out my original speakers and have just connected some Edifier MR3’s

I apologise for the rookie question but I want to get this right.

1) These are powered speakers so before I do the room correction test what volume level should I set the dial to on the speakers? The speakers don’t have a remote.

2) After the room correction do I just leave the volume dial on the speakers alone.

3) I had some advice regarding my speakers on the forum settings 800 mVrms. I see a setting in the app which is Vrms, is this the same thing?

4) Do I need to set 800 mVrms before the room correction.

Again, sorry for the basic questions but this is not something I have any experience in

Thank you
 
1) I ran room correction with the volume set for an average listening session. Seemed logical, but I'm sure someone will chastise me if necessary...
Whether that means high speaker volume with lower wiim volume, or max wiim volume with lower speaker volume I don't know, and don't even know if it'd matter much. In which case I'd say do the correction with your normal setup, probably fairly high speaker volume, seeing as they don't have a remote, and the wiim's volume set so that music isn't particularly quiet nor particularly loud.

2) see 1? i.e. leave speaker volume high?

3) The app should shiw 200 / 500 / 800 mVrms, and 1 / 2 Vrms.

4) Probably, yes, i.e. run correction with your planned config / setup..
 
1) These are powered speakers so before I do the room correction test what volume level should I set the dial to on the speakers? The speakers don’t have a remote.

2) After the room correction do I just leave the volume dial on the speakers alone.
Room correction doesn't really care about if you change the volume setting on the speakers. As long as you play the sweep tones at a reasonably high level you will be fine.

3) I had some advice regarding my speakers on the forum settings 800 mVrms. I see a setting in the app which is Vrms, is this the same thing?
Yes, 800 mVrms is the same as 0.8 Vrms.

4) Do I need to set 800 mVrms before the room correction.
The answer again is, it doesn't really matter.

Personally I would set up everything to my perfect liking before attempting room correction, but this is really just me. The reasons for setting up the output level and volume controls correctly are different.

Your speakers have an input sensitivity of 775 mV (= 0.775V). That means that they will play at full power when fed 775 mV. On one hand you don't want to overdrive the speakers' input with the loudest possible signal coming from the Ultra. On the other hand you will probably want to be able to get the maximum available power from them, at least for short bursts. Consequentially the maximum output signal from the Ultra should be as close to 775 mV as possible. 800 mV is the closest match.

Now, with the Ultra's volume control set to 100 and a full scale digital signal you could still overdrive the speakers, because 800 mV is obviously higher than 775 mV (which is just a 0.3 dB difference by the way). Leaving aside the +/- 50 mV tolerance specified for the input sensitivity, there are generally two ways to safely avoid this. You could either slightly reduce the volume on the speakers' volume knob or you could further reduce the Ultra's output. I vote for the latter. In device settings / audio settings there is a section called "Volume Limit". Reducing this value by 1 percentage point to 99% will decrease the Ultra's output level by 0.6 dB, so that alone will get you on the safe side.

From here on, things get a little more complicated, unfortunately. Room correction can apply boost (positive gain) at certain frequencies. This is applied in the digital domain and could lead to digital clipping with full scale signals, irrespective of any output voltage. So after running RC you will want to check the PEQ filters created by the room correction algorithm for positive gain values. If you find e.g. a maximum gain of 6 dB then you should decrease the "Volume Limit" by anther 10 percentage points to 89%, resulting in another 10 x 0.6 dB = 6 dB. One more example: If you see a PEQ gain of 4 dB, decrease the "Volume Limit" by 7 percentage points, resulting in a 4.2 dB digital level reduction.

This is actually not exactly the clean way of doing it. The total gain produced by different PEQ filters close to each other can result in an even higher combined gain than any of the individual gain values. Tools like REW (Room Equalization Wizard) can calculate the true safe amount of digital level reduction for you, but you need to learn hot to use it. For a start, have a look at the graph created by the room correction algorithm. If it visually looks like the highest peak is more than any of the individual gain values, reduce the Volume Limit a bit more.

Are you still reading?

If so, here is a final suggestion. If you still find that you never play your music so loud that you come close to full volume (100) with the Ultra, you should reduce the output level further from 800 mVrms to 500 mVrms. Leave the speakers volume control at max. As long as you can get as loud as you need to with the 0.5 Vrms output level, just leave it like this. It's generally better to run the digital volume control on the Ultra as high as possible.
 
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Room correction doesn't really care about if you change the volume setting on the speakers. As long as you play the sweep tones at a reasonably high level you will be fine.


Yes, 800 mVrms is the same as 0.8 Vrms.


The answer again is, it doesn't really matter.

Personally I would set up everything to my perfect liking before attempting room correction, but this is really just me. The reasons for setting up the output level and volume controls correctly are different.

Your speakers have an input sensitivity of 775 mV (= 0.775V). That means that they will play at full power when fed 775 mV. On one hand you don't want to overdrive the speakers' input with the loudest possible signal coming from the Ultra. On the other hand you will probably want to be able to get the maximum available power from them, at least for short for short bursts. Consequentially the maximum output signal from the Ultra should be as close to 775 mV as possible. 800 mV is the closest match.

Now, with the Ultra's volume control set to 100 and a full scale digital signal you could still overdrive the speakers, because 800 mV is obviously higher than 775 mV (which is just a 0.3 dB difference by the way). Leaving aside the +/- 50 mV tolerance specified for the input sensitivity, there are generally two ways to safely avoid this. You could either slightly reduce the volume on the speakers' volume knob or you could further reduce the Ultra's output. I vote for the latter. In device settings / audio settings there is a section called "Volume Limit". Reducing this value by 1 percentage point to 99% will decrease the Ultra's output level by 0.6 dB, so that alone will get you on the safe side.

From here on, things get a little more complicated, unfortunately. Room correction can apply boost (positive gain) at certain frequencies. This is applied in the digital domain and could lead to digital clipping with full scale signals, irrespective of any output voltage. So after running RC you will want to check the PEQ filters created by the room correction algorithm for positive gain values. If you find e.g. a maximum gain of 6 dB then you should decrease the "Volume Limit" by anther 10 percentage points to 89%, resulting in another 10 x 0.6 dB = 6 dB. One more example: If you see a PEQ gain of 4 dB, decrease the "Volume Limit" by 7 percentage points, resulting in a 4.2 dB digital level reduction.

This is actually not exactly the clean way of doing it. The total gain produced by different PEQ filters close to each other can result in an even higher combined gain than any of the individual gain values. Tools like REW (Room Equalization Wizard) can calculate the true safe amount of digital level reduction for you, but you need to learn hot to use it. For a start, have a look at the graph created by the room correction algorithm. If it visually looks like the highest peak is more than any of the individual gain values, reduce the Volume Limit a bit more.

Are you still reading?

If so, here is a final suggestion. If you still find that you never play your music so loud that you come close to full volume (100) with the Ultra, you should reduce the output level further from 800 mVrms to 500 mVrms. Leave the speakers volume control at max. As long as you can get as loud as you need to with the 0.5 Vrms output level, just leave it like this. It's generally better to run the digital volume control on the Ultra as high as possible.
Yes I’m still reading
Room correction doesn't really care about if you change the volume setting on the speakers. As long as you play the sweep tones at a reasonably high level you will be fine.


Yes, 800 mVrms is the same as 0.8 Vrms.


The answer again is, it doesn't really matter.

Personally I would set up everything to my perfect liking before attempting room correction, but this is really just me. The reasons for setting up the output level and volume controls correctly are different.

Your speakers have an input sensitivity of 775 mV (= 0.775V). That means that they will play at full power when fed 775 mV. On one hand you don't want to overdrive the speakers' input with the loudest possible signal coming from the Ultra. On the other hand you will probably want to be able to get the maximum available power from them, at least for short for short bursts. Consequentially the maximum output signal from the Ultra should be as close to 775 mV as possible. 800 mV is the closest match.

Now, with the Ultra's volume control set to 100 and a full scale digital signal you could still overdrive the speakers, because 800 mV is obviously higher than 775 mV (which is just a 0.3 dB difference by the way). Leaving aside the +/- 50 mV tolerance specified for the input sensitivity, there are generally two ways to safely avoid this. You could either slightly reduce the volume on the speakers' volume knob or you could further reduce the Ultra's output. I vote for the latter. In device settings / audio settings there is a section called "Volume Limit". Reducing this value by 1 percentage point to 99% will decrease the Ultra's output level by 0.6 dB, so that alone will get you on the safe side.

From here on, things get a little more complicated, unfortunately. Room correction can apply boost (positive gain) at certain frequencies. This is applied in the digital domain and could lead to digital clipping with full scale signals, irrespective of any output voltage. So after running RC you will want to check the PEQ filters created by the room correction algorithm for positive gain values. If you find e.g. a maximum gain of 6 dB then you should decrease the "Volume Limit" by anther 10 percentage points to 89%, resulting in another 10 x 0.6 dB = 6 dB. One more example: If you see a PEQ gain of 4 dB, decrease the "Volume Limit" by 7 percentage points, resulting in a 4.2 dB digital level reduction.

This is actually not exactly the clean way of doing it. The total gain produced by different PEQ filters close to each other can result in an even higher combined gain than any of the individual gain values. Tools like REW (Room Equalization Wizard) can calculate the true safe amount of digital level reduction for you, but you need to learn hot to use it. For a start, have a look at the graph created by the room correction algorithm. If it visually looks like the highest peak is more than any of the individual gain values, reduce the Volume Limit a bit more.

Are you still reading?

If so, here is a final suggestion. If you still find that you never play your music so loud that you come close to full volume (100) with the Ultra, you should reduce the output level further from 800 mVrms to 500 mVrms. Leave the speakers volume control at max. As long as you can get as loud as you need to with the 0.5 Vrms output level, just leave it like this. It's generally better to run the digital volume control on the Ultra as high as possible.
Yes I’m still reading 😀
I appreciate the explanation and I think I’m going to like the tweaking and fiddling that you describe. It will put me in good stead for when I purchase some better speakers and a amp in the future.

Anyway, I’ll have a go tomorrow with the new speaker and see how it sounds

Cheers
 
This is actually not exactly the clean way of doing it. The total gain produced by different PEQ filters close to each other can result in an even higher combined gain than any of the individual gain values. Tools like REW (Room Equalization Wizard) can calculate the true safe amount of digital level reduction for you, but you need to learn hot to use it.

As I recall, it wasn’t that much of a learning curve to download REW and enter the WiiM RC PEQ values to get it to work out the necessary headroom as per this link

 
Is PowerAmp Equilizer Pro an android app? Had a Quick Look and couldn’t see it on the apple apps store?

Ok, gave the room correction a go and chose to calibrate left and right separately as my lounge is an odd shape

One of the speakers has 9+ gain I see. Any thoughts? If you can direct me to the Power amp program I’d be greatful and maybe I can plug in all these figures to sort out the setup.

At present I’ve taken Harkpabst’s advice before room correction and set my speakers to 800 mVrms and reduced the max volume to 99%

Left Speaker and Right speaker results

IMG_2098.png


IMG_2099.png
IMG_2100.png
IMG_2101.png

IMG_2102.png
 
He guys I missed the suggestion to download REW. I’ll grab this shortly, but for those that use it, I’d like to ask a question.

There are two ways with the WiiM Ultra to do room correction. Stereo ie both speakers at the same time and also doing one speaker and then the other.

Will REW be able accommodate both methods and figures?

Again, I don’t know much about all this stuff and therefore can’t really tell what good or bad. One thing that I did notice that when doing the stereo vs seperate room correction, there were higher gain values as shown in the pictures here. One as high as 9

I assume the goal is to get the actual line nearer the yellow line? So one I’ve worked out the max volume % do you retest or will that bring those two lines together and no need for another room test.
 
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Will REW be able accommodate both methods and figures?
If I remember correctly from the top of my head REW allows to work with one set of PEQ filters at a time. When using independent left/right room correction you would have to enter one of the results at a time and take note of the required headroom. The take the higher value and decide it by 0.6 dB to determine the number of percentage point you have to lower the volume limit.

One thing that I did notice that when doing the stereo vs seperate room correction, there were higher gain values as shown in the pictures here. One as high as 9
First off, your measurements generally look rather good to me. Ignore the peak between 8 kHz and 16 kHz, it's just the typical misbehaviour found with most all smartphone mics and not used by WiiM RC.

It actually makes sens that the individual correction results in higher gain values, in particular down around 40 Hz. The output of both speakers combined is close to the target. With individual correction you see that this is because one is pretty much on target while the other one is somewhat lacking. The thing is: You won't be able to notice if 40 Hz is played by the left or the right speaker.

I would try and compare stereo correction from 40 Hz to 4000 Hz (or maybe even 3000 Hz) and individual correction from 50 Hz to 4000 Hz.
 
Ok I’ll test in stereo… So if I’m going to disregard the peaks you mentioned then I assume I can’t use REW as I will be omitting some of the readings
? I could work out the max percentage of the volume based on the figures left over?

I believe you did mention a way of doing it at the beginning of the post but said it wasn’t ideal.

Lastly, I noticed a settings menu for Room correction and wondered if everything checks out?

I’m sure I’m overthinking things, but I like to get things right. I really appreciate your patience as I’m sure some of my questions are a little silly. 🤪

IMG_2105.png
 
Lastly, I noticed a settings menu for Room correction and wondered if everything checks out?
These are the default settings and they are default for a reason: They often work out well. :)

However, I recommend to increase the lower equalize frequency limit (in your case) from 40 Hz to >= 50 Hz if using independent left/right correction. The reason was the massive 9 dB gain for one channel only, which isn't that much useful. Alternatively, stereo correction should yield good results in your case, too.

So if I’m going to disregard the peaks you mentioned then I assume I can’t use REW as I will be omitting some of the readings
? I could work out the max percentage of the volume based on the figures left over?
No, no, absolutely not. I wasn't clear enough. Just don't bother with everything in the measurements above 4000 Hz. The graphs look like your speaker had a massive spike in there transfer function between 8 kHz and 16 kHz, but they don't. These are just artefacts produced by your phone's microphone.

You do need to take into account all gain values for all PEQ filters created by the RC process. We just use the tinies fraction of what REW can do here to determine how much reduction we need in the volume limit setting to safely avoid digital clipping.

You need to enter all 10 PEQ filters created by WiiM RC into REW manually and as a result REW can tell you how much digital gain is applied in total. This can (but doesn't have to) be more than the highest individual gain for any single PEQ band. REW will calculate this value exactly. If you just reduce the volume limit based on the highest individual gain, you still could end up suffering from digital clipping.

Nothing wrong with thinking about the concepts of digital room EQ. You can go pretty far before it's really "overthinking" things. ;)
 
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Ok that’s clearer… Just to clarify, if I decide on the stereo RC I don’t need to set 50hz, I leave it at 40hz

If memory serves when I initially did the stereo RC the highest gain reading was 6 ish
 
Ok that’s clearer… Just to clarify, if I decide on the stereo RC I don’t need to set 50hz, I leave it at 40hz

If memory serves when I initially did the stereo RC the highest gain reading was 6 ish
Yes, that's what I wanted to say. :)

And this is not divine knowledge but just my personal recommendation as a sensible starting point. You are free to experiment.
 
Great, I appreciate the help thank you!

I’ll use your suggestions but I think I really need to do some reading up about the whole subject before I experiment
 
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