UMIK-1 arrived

[slartibartfast]

Nothing wrong with that.

The term "phase" usually describes a variation in timing relative to a full 360⁰ sine wave. The 0⁰/180⁰ "phase" switch is actually a bit of a misnomer because it doesn't shift anything in the time domain. It just inverts the polarity (or "absolute phase") of the signal.

Surprisingly, quite a number of amplifiers do not preserve the absolute phase and human beings are usually not sensitive to it. However, if you combine two separately amplified sources (like e.g. a sub and an amp with passive speakers or a a pair of active speakers) you should always check which polarity results in clean summation with no dips.

0⁰ or 180⁰, it doesn't really matter as.long as.the outcome is OK

I wonder if the WiiM Amp preserves absolute phase. I get a better result with the sub output switched to 180 degrees but I actually use a delay of 6ms which is half a cycle at 80Hz. I wonder if I should use 180 degrees instead.

 

[EddNog]

I wonder if the WiiM Amp preserves absolute phase. I get a better result with the sub output switched to 180 degrees but I actually use a delay of 6ms which is half a cycle at 80Hz. I wonder if I should use 180 degrees instead.

Nothing wrong with doing this.

The SVS subs, in fact, have phase adjustment in 1-degree granular increments, from 0-180 degrees, and then a separate polarity toggle, so it really covers anywhere from 0-360 degrees in single degree increments. There have been scenarios (before I bought a miniDSP) where I even had to turn on the 180 degree toggle and then add some additional phase on top of that, effectively going past 210 degrees.

-Ed

 

[harkpabst]

I wonder if the WiiM Amp preserves absolute phase. I get a better result with the sub output switched to 180 degrees but I actually use a delay of 6ms which is half a cycle at 80Hz. I wonder if I should use 180 degrees instead.

I never tested this but @dominikz found out that the WiiM Amp Pro currently inverts the phase at the speaker terminals (but not the subwoofer output).

My pragmatic approach would be to try either polarity and see which requires the lesser amount of delay for perfect acoustical summation.

 

[slartibartfast]

I never tested this but @dominikz found out that the WiiM Amp Pro currently inverts the phase at the speaker terminals (but not the subwoofer output).

My pragmatic approach would be to try either polarity and see which requires the lesser amount of delay for perfect acoustical summation.

Interesting, that would make sense. It would explain why I need a 6ms delay when the sub is sitting right next to the right speaker.

 

[EddNog]

Interesting, that would make sense. It would explain why I need a 6ms delay when the sub is sitting right next to the right speaker.

Any subwoofer that has DSP also has its own inherent delay/lag. On average, SVS subs with DSP suffer an additional ~7.4ms delay. KEF subs with DSP also have some degree of lag, etc. Should expect this with WiiM Sub Pro too.

-Ed

 

[slartibartfast]

Any subwoofer that has DSP also has its own inherent delay/lag. On average, SVS subs with DSP suffer an additional ~7.4ms delay. KEF subs with DSP also have some degree of lag, etc. Should expect this with WiiM Sub Pro too.

-Ed

My BK XLS200 doesn't have any DSP though which is why the 6ms always bothered me.

 

[harkpabst]

There are still some purely analogue subwoofers, like e.g. the entire BK Electronics range.

Edit: Too late ...

 

[EddNog]

My BK XLS200 doesn't have any DSP though which is why the 6ms always bothered me.

There are still some purely analogue subwoofers, like e.g. the entire BK Electronics range.

Edit: Too late ...

Honestly, had my budget allowed it, I would've preferred servo-controlled subs through my entire system, but that was WAY beyond the realm of affordability for me. Almost impossible to find Rythmik subs in the secondary market, and prices for new units, especially now in the age of tariffs driven by the asshole you couldn't have paid me to vote for, is truly prohibitive. I got all of my subs either refurb or open-box (minimum one-year if not full manufacturer's warrantied), which is very easy to find with SVS.

-Ed

 

[slartibartfast]

I never tested this but @dominikz found out that the WiiM Amp Pro currently inverts the phase at the speaker terminals (but not the subwoofer output).

My pragmatic approach would be to try either polarity and see which requires the lesser amount of delay for perfect acoustical summation.

This thread from ASR mentions better results with the sub output inverted.

Time align with Wiim amp using Rew

Yes, I used one channel only. I made the choice without any expectation that it makes much of a difference. Left channel is nearer to the door, so I figured it might have slightly less room reinforcement in the low frequencies, so I preferred that one for that reason, assuming that either gain...

www.audiosciencereview.com

 

[harkpabst]

Still, I wouldn't go by other buyers' experience. You never know what's different in their setup. The amp built into a certain sub could also invert the case. By (careless) design.

Or - even worse - some trainee might have mixed up the polarity when connecting the woofer on his side of the workshop desk while his pal on the other side did it right.

Yes, 100% QA would detect such errors in theory, if this check is part of the routine. In mtiway loudspeakers it is often necessary to invert the polarity of one or more drivers. Usually this is dealt with by connecting the cables out of phase at the crossover, so trainees assembling the speakers don't have to think about it, but you never know.

The first batch of Fosi V3 Mono amps (those obtained throug Kickstarter) came with inverted polarity, which was corrected during series production. Imagine a pair of monoblocks being ripped apart for other use cases and later paired with single units from a different batch.

And finally such behaviour might even be changeable through software with digital devices ...

Long story short: Better trust your own measurements, especially if you've already experienced strange behaviour.

 

[khuntim]

new speakers, sort of a side-grade so far.

USB-C input doesn't work very well, much lower volume, almost too low. and appears way more latency.

using USB input I tried checking latency with Ultra at the listening position and on shelf near speakers.

Optical sounds better, maybe just too much processing with USB input, but measurements say flatter response from Optical input before correction.

line-out to AUX input next to mess with.

180° still best for the sub. using RF 20hz-400hz. I set speaker latency to the original measurement of 11ms because I am totally lost.

Not the correct way to measure this.. need to grow up and use REW

sub blends pretty well, still sort of prefer without the sub.


USB with Ultra in both positions:


with optical latency looked like this:



with USB:

with optical:

final using optical input,

 

[khuntim]

Line-out to AUX:

 

[harkpabst]

Optical sounds better, maybe just too much processing with USB input, but measurements say flatter response from Optical input before correction.

Don't fall for the idea of "too much processing" killing the sound "because less is more". This does not apply here.

There are real measurable acoustical effects at work, not audiophile philosophy.

USB with Ultra in both positions:


with optical latency looked like this:

Great results! As you found out there's quite a difference between USB and optical. And the results will be different for RCA again!

These values perfectly explain the first part of the puzzle: Each output (and speaker input!) can have a different latency!

What's are the consequences? Whenever you compare any connection type (USB, optical, RCA) you absolutely must dial in the correct delay prior to performing a RoomFit run. Otherwise the results wil be flawed.

The second part is simple as level differences. As an be clearly seen, the relative level of the subwoofer compared to the main speakers differs significantly. It's the main speakers level that really varies, of course, with USB being clearly the lowest.

RoomFit can take care of these differences to a certain degree but that's far from ideal. It would be much better to adjust the subwoofer level in the WiiM Home app accordingly before running RoomFit. Even doing it very roughly by ear should be better than nothing. So far the assessment of the optical connection looks best but when dialed in correctly (polarity switch, delay and level) there shouldn't be such massive differences at all.

sub blends pretty well, still sort of prefer without the sub.

You cannot be satisfied with this result.

need to grow up and use REW

And this might be part of the solution.

What's your current crossover frequency? Is the subwoofer's upper limit far enough above this value?

 

[khuntim]

Don't fall for the idea of "too much processing" killing the sound "because less is more". This does not apply here.

There are real measurable acoustical effects at work, not audiophile philosophy.


Great results! As you found out there's quite a difference between USB and optical. And the results will be different for RCA again!

These values perfectly explain the first part of the puzzle: Each output (and speaker input!) can have a different latency!

What's are the consequences? Whenever you compare any connection type (USB, optical, RCA) you absolutely must dial in the correct delay prior to performing a RoomFit run. Otherwise the results wil be flawed.

The second part is simple as level differences. As an be clearly seen, the relative level of the subwoofer compared to the main speakers differs significantly. It's the main speakers level that really varies, of course, with USB being clearly the lowest.

RoomFit can take care of these differences to a certain degree but that's far from ideal. It would be much better to adjust the subwoofer level in the WiiM Home app accordingly before running RoomFit. Even doing it very roughly by ear should be better than nothing. So far the assessment of the optical connection looks best but when dialed in correctly (polarity switch, delay and level) there shouldn't be such massive differences at all.


You cannot be satisfied with this result.


And this might be part of the solution.

What's your current crossover frequency? Is the subwoofer's upper limit far enough above this value?

Sub is crossed over at 80hz, but it's 6.5" sub, specs do not say frequency range, just that it will go to 37hz. I always thought if crossover was too high it would become more directional, sub is dead center between the speakers. room is roughly 9'x11' my ears are about 2m from speakers.

Right now the bass sounds too flat if that makes sense. The speakers are missing top end. Detail in music I am familiar with isn't there. I can hear with the headphones. I guess that would be where EQ would come in.

I like the idea of working on getting it close by ear before running. so RoomFit uses whatever EQ settings/Pre gain/etc. set in Home app?

the hardest thing seems the latency. the rough calculation by measuring is not going to be perfect of course.

where does the Sync Audio/Auto sync setting fit in all this?

While I am learning to use REW, is there an advantage to putting the Ultra in the listening position for the latency test? I have a 3m optical as of today. not hard to do.

this was the speakers without sub using USB input:



Can't thank you and everyone else enough for all the help. I have learned a lot.

 

[EddNog]

Sub is crossed over at 80hz, but it's 6.5" sub, specs do not say frequency range, just that it will go to 37hz. I always thought if crossover was too high it would become more directional, sub is dead center between the speakers. room is roughly 9'x11' my ears are about 2m from speakers.

Right now the bass sounds too flat if that makes sense. The speakers are missing top end. Detail in music I am familiar with isn't there. I can hear with the headphones. I guess that would be where EQ would come in.

I like the idea of working on getting it close by ear before running. so RoomFit uses whatever EQ settings/Pre gain/etc. set in Home app?

the hardest thing seems the latency. the rough calculation by measuring is not going to be perfect of course.

where does the Sync Audio/Auto sync setting fit in all this?

While I am learning to use REW, is there an advantage to putting the Ultra in the listening position for the latency test? I have a 3m optical as of today. not hard to do.

this was the speakers without sub using USB input:

View attachment 25748

Can't thank you and everyone else enough for all the help. I have learned a lot.

If you’re able to place the streamer itself right where your head is during listening and then running the Sub/Speaker sync (not the multi room sync), that would work fine and probably preclude you from necessarily needing to use REW. That is not an option for me, but I also have five speakers to sync, so…

Placing your sub precisely equidistant from both speakers (dead center) allows you to cross over higher without too much impact to imaging. The downside to this is that you can’t corner load the sub to get more extension and headroom to work with. If you keep the sub equidistant from both speakers but push it back against the wall behind the sound system, you can at least get boundary reinforcement from the back wall which will improve bottom-end extension and efficiency. The room correction will correct for any excess gain or peaks, so don’t worry if it sounds like too much before you apply correction. It sounds like your sub is on the smaller side, so I would suggest keeping the crossover below 100Hz as it sounds like it’s already pushing towards its ceiling. People running a sub dead center sometimes will crossover as high as 120Hz without suffering too much detriment to imaging, but I think that’s not ideal for your speaker & sub combo. You can also try lowering the crossover down to 70Hz and pushing it farther back to the back wall (if it isn’t already there), and you’ll see the sub extend quite a bit downward.

-Ed

 

[harkpabst]

Sub is crossed over at 80hz, but it's 6.5" sub, specs do not say frequency range, just that it will go to 37hz

The important bit is to not use the subwoofer's built-in crossover. It most probably has a knob labeled with different frequencies. Turn this knob fully clockwise to the maximum position. Do not set it to 80 Hz if you want to cross at 80 Hz. The WiiM will do all that for you, in most cases better than the sub can. If there is an LFE position or an LFE switch, use this instead.

The reason is that you want the steepness of the effective acoustical low pass of the sub and the steepness of the effective acoustical high pass of the mains to be fully symmetrical. The WiiM Ultra (Amp, Amp Pro, Amp Ultra) employ a relatively steep symmetrical 4th order low pass and high pass. This ensures smooth transition between sub and mains if and only if the mains are still linear down to roughly half of the crossover frequency and sub can play up to about twice the crossover frequency.

Example: When crossing at 80 Hz then the sub (without the WiiM's filtering) should ideally play up to ~160 Hz and the mains should play down to ~40 Hz. A couple of Hz plus/minus don't matter, we don't have to be overly strict here. But if your sub e.g. brings along its own low pass filter at 80 Hz (in addition to the WiiM's low pass filter) things will never fully work out. The sound pressure level right at the crossover frequency will be too low and the filter slopes are no longer symmetrical. The effective acoustical low pass of the sub will probably be a 6th or 7th order filter and won't sum up cleanly with the mains.

There is a different school of thought proposing to cross the sub right at the -3 dB frequency of the mains. Such an approach can work, but in practice it's far more complicated than the advocates of this method usually think. Achieving a good integration is not easier but a lot harder this way and absolutely impossible without proper measurements (or massive amounts of luck). There are more disadvantages, which I won't mention here.

I always thought if crossover was too high it would become more directional, sub is dead center between the speakers. room is roughly 9'x11' my ears are about 2m from speakers.

As @EddNog already mentioned, crossing even much higher than 80 Hz is no problem in a symmetrical setup. In my Ultra based system small 4" full range speakers are crossed to a centrally places sub at 110 Hz and thanks to WiiM's EQ and sub management the sound is superb.

Right now the bass sounds too flat if that makes sense. The speakers are missing top end.

Unbalanced sound at one end of the frequency spectrum can actually influence our perception of the other end. Once you find this right balance everything should sound equally good.

I like the idea of working on getting it close by ear before running. so RoomFit uses whatever EQ settings/Pre gain/etc. set in Home app?

RoomFit currently uses peak filters (broad band, low Q and narrow band, high Q) only. It doesn't touch pre-gain, the subwoofer level, delay or any other setting.

the hardest thing seems the latency. the rough calculation by measuring is not going to be perfect of course.

where does the Sync Audio/Auto sync setting fit in all this?

Get the filter slopes right first (as much as possible, no low pass filtering by the sub itself). No other setting can correct this later on.

I think you have reasonable starting points for the delay right now, at least for USB and optical. If you want to try the DAC built into the Ultra you should repeat the same procedure for RCA. Use that as a starting point. Play an 80 Hz sine or pink noise (or low pass filtered pink noise) and adjust the delay in 1 ms steps either direction. Whatever value results in more volume is better. Next adjust the overall bass level until the sub blends with the mains (and maybe check the delay one more time). A little too much volume from the sub won't hurt. Then you should be good to go with RoomFit.

Sync Audio is for syncing two or more WiiM devices in a multi-room music setup. It's unrelated.

While I am learning to use REW, is there an advantage to putting the Ultra in the listening position for the latency test? I have a 3m optical as of today. not hard to do.

When using REW with the UMIK-1 connected to your PC the microphone built into the Ultra is no longer used. You use REW and enter the delay value manually.

If you keep the sub equidistant from both speakers but push it back against the wall behind the sound system, you can at least get boundary reinforcement from the back wall which will improve bottom-end extension and efficiency. The room correction will correct for any excess gain or peaks, so don’t worry if it sounds like too much before you apply correction.

Yep!

 

[khuntim]

If you’re able to place the streamer itself right where your head is during listening and then running the Sub/Speaker sync (not the multi room sync), that would work fine and probably preclude you from necessarily needing to use REW. That is not an option for me, but I also have five speakers to sync, so…

Placing your sub precisely equidistant from both speakers (dead center) allows you to cross over higher without too much impact to imaging. The downside to this is that you can’t corner load the sub to get more extension and headroom to work with. If you keep the sub equidistant from both speakers but push it back against the wall behind the sound system, you can at least get boundary reinforcement from the back wall which will improve bottom-end extension and efficiency. The room correction will correct for any excess gain or peaks, so don’t worry if it sounds like too much before you apply correction. It sounds like your sub is on the smaller side, so I would suggest keeping the crossover below 100Hz as it sounds like it’s already pushing towards its ceiling. People running a sub dead center sometimes will crossover as high as 120Hz without suffering too much detriment to imaging, but I think that’s not ideal for your speaker & sub combo. You can also try lowering the crossover down to 70Hz and pushing it farther back to the back wall (if it isn’t already there), and you’ll see the sub extend quite a bit downward.

-Ed

Great! yeah, with this small setup, the sub can only be under the TV shelf and near the wall.

I'll try to figure out a stand for the Ultra. Is the mic on the rear? maybe point that forward?

Like you were saying - would be nice if the external mic could do this.

 

[khuntim]

The important bit is to not use the subwoofer's built-in crossover. It most probably has a knob labeled with different frequencies. Turn this knob fully clockwise to the maximum position. Do not set it to 80 Hz if you want to cross at 80 Hz. The WiiM will do all that for you, in most cases better than the sub can. If there is an LFE position or an LFE switch, use this instead.

I am using the LFE input, but not sure if the crossover knob has any effect, I will turn that all the way up just in case.

The reason is that you want the steepness of the effective acoustical low pass of the sub and the steepness of the effective acoustical high pass of the mains to be fully symmetrical. The WiiM Ultra (Amp, Amp Pro, Amp Ultra) employ a relatively steep symmetrical 4th order low pass and high pass. This ensured smooth transmission between sub and mains if and only if the mains are still linear down to roughly half of the crossover frequency and sub can play up to about twice the crossover frequency.

Great info.

Get the filter slopes right first (as much as possible, no low pass filtering by the sub itself). No other setting can correct this later on.

I can change the slope of the crossover? Sort of new to all of this.

I think you have reasonable starting points for the delay right now, at least for USB and optical. If.you want.to try the DAC built into the Ultra you should repeat the same procedure for RCA. Use that as a starting point. Play an 80 Hz sine or pink noise (low pass filtered pink noise) and adjust the delay in 1 ms steps either direction. Whatever results in more volume is better. Next adjust the overall bass level until the sub blends with the mains (and maybe check the delay one more time). A little.to.much volume from the sub won't hurt. Then you should be good to go with RoomFit.

I'll have to try this, will look for a test file. Honestly I am pretty lost with the latency numbers, I have one that says "Sub leads main speakers buy 2ms (optical), and another that says "sub leads main speakerss by 27ms. (USB)

going to try again with the Ultra in listening position (USB and Optical) do not have long RCAs yet.

When using REW with the UMIK-1 connected to your PC the microphone built into the Ultra is no longer used. You use REW and enter the delay value manually.

Will be great to finally learn this. back in town soon

As @EddNog already mentioned crossing even much higher than 80 Hz is no problem. In my Ultra based system small 4" full range speakers are crossed to a centrally places sub at 110 Hz and thanks to WiiM's EQ and sub management the sound is superb.

I'll try highter 100/110hz also. these are 4" drivers...

thanks again

 

[EddNog]

I am using the LFE input, but not sure if the crossover knob has any effect, I will turn that all the way up just in case.


Great info.

I can change the slope of the crossover? Sort of new to all of this.


I'll have to try this, will look for a test file. Honestly I am pretty lost with the latency numbers, I have one that says "Sub leads main speakers buy 2ms (optical), and another that says "sub leads main speakerss by 27ms. (USB)

going to try again with the Ultra in listening position (USB and Optical) do not have long RCAs yet.


Will be great to finally learn this. back in town soon


I'll try highter 100/110hz also. these are 4" drivers...

thanks again

Slopes (24dB/Octave, 30dB/Octave, etc.) and even filter/slope types (Butterworth, Linkwitz-Riley, etc.) are both a thing. I use miniDSP for bass management and I have more than 10 different options to pick from just on this, let alone frequency and polarity. Crossovers are just a very deep rabbit hole for a job.

-Ed

 

[slartibartfast]

Slopes (24dB/Octave, 30dB/Octave, etc.) and even filter/slope types (Butterworth, Linkwitz-Riley, etc.) are both a thing. I use miniDSP for bass management and I have more than 10 different options to pick from just on this, let alone frequency and polarity. Crossovers are just a very deep rabbit hole for a job.

-Ed

They are a thing but you can't change them in the WiiM app.