Beta Test: Room Correction for Android

[Bruce]

Right, so I will stick with Umik1 plugged to Android (that is without the help of the calibration file).

 

[Flatron7]

Why would you want to use the iMM-6c instead of the UMIK-1? Just for convenience? The UMIK-1 should be the slightly better device, I think.

The WiiM Home App already has permission to use "the microphone". USB mics are fully managed and integrated by Android, WHA just uses the mic presented to it by the OS. I wouldn't expect any additional permission to be asked for.

I don't have a WiiM Pro, but with the Amp and the Ultra the default configuration for RC is to only correct between 40 Hz an 4000 Hz. The measurement will still be taken full-range. Trying to correct higher up the frequency range is tricky anyway, but should be specifically avoided with no calibration file.

A USB mic doesn't need a calibration file to represent the correct absolute sound pressure level. But it still needs some correction of it's frequency response, mainly below 40 Hz and above 4000 Hz.

Hi, I have an external microphone Umik -1 but currently it is not possible to load the calibration file. It would be nice if we could load the calibration files. Do you know if it is planned to be possible to load the calibration file in the near future?

 

[mlsstl]

Hi, I have an external microphone Umik -1 but currently it is not possible to load the calibration file. It would be nice if we could load the calibration files. Do you know if it is planned to be possible to load the calibration file in the near future?

My observation is that a calibration file is an unnecessary worry for home users. The calibration file I downloaded for my IMM-6C shows no more than a 0.5 dB variation from ruler-flat up to 10 KHz. I get far bigger deviations every time I re-run the program in my room -- every different position in the room is going to have its own, often dramatic, peaks and valleys, so unless you are going to listen with your head in a vise, the use of a calibration file is rather meaningless (unless your microphone is way off in which case they shouldn't have sold it to you.)

 

[Flatron7]

My observation is that a calibration file is an unnecessary worry for home users. The calibration file I downloaded for my IMM-6C shows no more than a 0.5 dB variation from ruler-flat up to 10 KHz. I get far bigger deviations every time I re-run the program in my room -- every different position in the room is going to have its own, often dramatic, peaks and valleys, so unless you are going to listen with your head in a vise, the use of a calibration file is rather meaningless (unless your microphone is way off in which case they shouldn't have sold it to you.)

Can you quantify what you mean by "very far"? I only know that it is highly recommended to use the calibration file in microphone like umik etc. When I used REW and DIRAC live I always used it. I think that for WIIM programmers implementing this functionality is not a big problem. For high frequencies and below 40hz calibration is very important. if your microphone has few differences it is a good thing for you. Thanks anyway for the kind reply.

 

[slartibartfast]

Can you quantify what you mean by "very far"? I only know that it is highly recommended to use the calibration file in microphone like umik etc. When I used REW and DIRAC live I always used it. I think that for WIIM programmers implementing this functionality is not a big problem. For high frequencies and below 40hz calibration is very important. if your microphone has few differences it is a good thing for you. Thanks anyway for the kind reply.

You probably don't need to worry about high frequencies or frequencies less than 40Hz though. Most users recommend only correcting up to 300-400Hz and even the default settings are 40-4000Hz.

 

[mlsstl]

Can you quantify what you mean by "very far"? I only know that it is highly recommended to use the calibration file in microphone like umik etc. When I used REW and DIRAC live I always used it. I think that for WIIM programmers implementing this functionality is not a big problem. For high frequencies and below 40hz calibration is very important. if your microphone has few differences it is a good thing for you. Thanks anyway for the kind reply.

I think, like many things in audio, it is a matter of opinion and perspective. I know that when I re-run sweeps (either REW or Ultra RC) that moving the microphone even a few inches can result in different peaks and dips of several dB or more, with the frequencies involved also changing. A correction made with the microphone in one spot will appear wrong when the microphone is moved to a different spot. Often only inches are involved.

This is due to phase cancelation occurring because there are two speakers involved meaning that the nodes vary depending on where the measurement microphone is placed and the frequencies involved, since the wavelength gets shorter as the frequency increases. Even room temp and the barometric pressure are factors if one is getting really picky about things.

Now, one can argue that room correction sweeps should be done separately for the left and right channels, but the problem with that is that you'll be back to having both speakers playing when you start listening to music instead of test sweeps, so you've just brought the phase cancellation nodes and antinodes back into play.

I'm at the point where I find I can get an improvement in overall sound quality with WiiM's room correction, though I generally back off some of the larger corrections it makes after doing multiple sweeps and shooting for the average of those results. However, I'm also aware the others are going to do things differently.

 

[bernard23]

After multiple sweeps with the Dayton mics using wiim RC and also Spectroid app I developed a simpler less aggressive profile than that which Wiim came up with for my room.
It sounds great, it's not asking big demands of my amp and it's correcting the worst room anomalies. It's not perfect but then I never sit in EXACTLY the same position, and I'm not about to do an RC every time I sit down.

 

[Hazenhart]

Just starting to experiment with the PEQ and room correction. I am seeking one bit of clarification from the collected wisdom here:

Is it recommended to adjust pre gain in response to PEQ boosts? For example, if my PEQ has a +6 db peak, should the pre gain be correspondingly reduced to -6 db to prevent clipping?

Thanks for your time.

 

[Wiimer]

Just starting to experiment with the PEQ and room correction. I am seeking one bit of clarification from the collected wisdom here:

Is it recommended to adjust pre gain in response to PEQ boosts? For example, if my PEQ has a +6 db peak, should the pre gain be correspondingly reduced to -6 db to prevent clipping?

Thanks for your time.

I don't think so.
Volume limit should be less than 90%.

dB/0.6 = minimum volume limit required (%)
6dB/0.6=10%

In my opinion, pre-gain is a function that reduces the relative volume difference between per-input.

 

[harkpabst]

In theory you could also reduce the pre-gain for all sources (or maybe just not for those that are low on volume, anyway). But why bother with x settings for one issue if you can do the same with one single setting?

I still like being able to apply pre-gain, but just for the sake of reaching equal volume between sources.

 

[Hazenhart]

I don't think so.
Volume limit should be less than 90%.

dB/0.6 = minimum volume limit required (%)
6dB/0.6=10%

In my opinion, pre-gain is a function that reduces the relative volume difference between per-input.

Thanks.
I am only using one source (wifi), so my adjustments are purely for maintaining optimal gain. The pre gain is noted in db, so that seems and easy one to get right, but your volume limit conversion is also simple.

Primary question though:

Does the adjustment (whether by pre gain or by volume limit) really need to be made? When eq-ing my AVR (Denon), I don't change any volume or overall gain settings. Same with anything with tone controls.

 

[jmudrick]

Thanks.
I am only using one source (wifi), so my adjustments are purely for maintaining optimal gain. The pre gain is noted in db, so that seems and easy one to get right, but your volume limit conversion is also simple.

Primary question though:

Does the adjustment (whether by pre gain or by volume limit) really need to be made? When eq-ing my AVR (Denon), I don't change any volume or overall gain settings. Same with anything with tone controls.

I figure better to be safe. No single answer as it depends on frequency of the upward adjustment and how much headroom you have with your particular speakers and amp going in at that level.

 

[harkpabst]

It shouldn't be too hard to test this, though, using an extreme example. Yet, I was too lazy to ever do it and use the "better safe than sorry" excuse, too.

Let me add that I did play around with this just a little and didn't ever perceive any digital clipping ...