Room Correction with sub

[Dennis from Venice]

I spent a bit of time playing with room correction and varying the crossover frequency. Each time I had a major dip in frequency in the vicinity of the crossover I chose. And it required a major (>10 dB) correction.

In the past, I've used REW and Audyssey and had a fairly even sub frequency from 20-100 Hz and I'm not getting that here. I suspect it might be the iPhone mike (???). I'm going to dig out my USB mike and try REW again.

I suspect the other idea is to turn off the sub in room correction and use my sub's crossover adjustment.

I'm more than puzzled my this, but the resulting eq corrected sound doesn't sound that bad.

 

[slartibartfast]

I spent a bit of time playing with room correction and varying the crossover frequency. Each time I had a major dip in frequency in the vicinity of the crossover I chose. And it required a major (>10 dB) correction.

In the past, I've used REW and Audyssey and had a fairly even sub frequency from 20-100 Hz and I'm not getting that here. I suspect it might be the iPhone mike (???). I'm going to dig out my USB mike and try REW again.

I suspect the other idea is to turn off the sub in room correction and use my sub's crossover adjustment.

I'm more than puzzled my this, but the resulting eq corrected sound doesn't sound that bad.

If you have a dip at the crossover frequency you can probably play around with sub latency settings in the subwoofer menu.

 

[harkpabst]

Either sub latency or mains latency, whatever works out best.

 

[Dennis from Venice]

I tried that........seems no matter where I put the mains or sub latency or crossover I get something like this:



I have KEF LS50's good to 80 Hz and a KEF KC62 sub. KEF recommends the crossover at 80 and I tried 60-140 with no luck

 

[alpha_zulu]

Can you overlap the frequencies? Maybe highpass your mains at 60 Hz und lowpass the sub at 80 Hz. I don't know if this is possible because don't own an Ultra.

Or can you change slope to less steep? Should also help.

 

[Dennis from Venice]

I just ran a sweep using REW with a calibrated USB mike and no EQ in the Ultra......and got a pretty flat response end to end. This is pretty close to what I've seen in the past. Also with Audyssey.

I used optical to get the REW sweep into the Ultra (I can also use Roon and WiFi for the sweep if that will make a difference). The X axis is truncated but the red measurement is a 20-20k Hz sweep left to right



I'm going to switch my sub to do the crossover at 80 and turn the volume down a touch and see if that is the solution

 

[harkpabst]

I just ran a sweep using REW with a calibrated USB mike and no EQ in the Ultra......and got a pretty flat response end to end. This is pretty close to what I've seen in the past. Also with Audyssey.

I used optical to get the REW sweep into the Ultra (I can also use Roon and WiFi for the sweep if that will make a difference). The X axis is truncated but the red measurement is a 20-20k Hz sweep left to right

View attachment 10707

I'm going to switch my sub to do the crossover at 80 and turn the volume down a touch and see if that is the solution

That screenshot doesn't tell us anything, unfortunately, since the y axis is fully and the X axis partly truncated.

Please, click on "limits", the "fit to data" and take the screenshot using REW's own graphics export tool.

 

[Dennis from Venice]

That screenshot doesn't tell us anything, unfortunately, since the y axis is fully and the X axis partly truncated.

Please, click on "limits", the "fit to data" and take the screenshot using REW's own graphics export tool.

I didn't save it. I was doing a quick and dirty check and not a detailed analysis. Maybe I'll do a thorough REW later today.

But the result was a flat line from 20-20K and quite a difference from the Ultra curve.

 

[harkpabst]

I didn't save it. I was doing a quick and dirty check and not a detailed analysis. Maybe I'll do a thorough REW later today.

But the result was a flat line from 20-20K and quite a difference from the Ultra curve.

It might be flat, but we cannot tell without knowing the y axis scale.

What did you measure btw.?

 

[Dennis from Venice]

It might be flat, but we cannot tell without knowing the y axis scale.

What did you measure btw.?

I measured L+R + Sub but I had the mike in a weird spot....I'm going to redo it with the mike in the listening position

 

[Dennis from Venice]

I did a more thorough run with REW and the results had a similar pattern to Ultra but the dB filter corrections were less with REW except REW had the sub 20Hz to 40Hz quite a bit higher than Ultra. One difference is that I ran REW only at 44.1kHz.

I may run through a lot more and develop a convolution filter for Roon and shut off EQ with Ultra.

 

[jed1]

@dlaslo do you feed Ultra line out to KC62 line in and feed KC 62 line out to the amplifier. Maybe, your subwoofer's crossover is better than Ultra for matching the main and the subwoofer.

 

[Dennis from Venice]

@dlaslo do you feed Ultra line out to KC62 line in and feed KC 62 line out to the amplifier. Maybe, your subwoofer's crossover is better than Ultra for matching the main and the subwoofer.

I use the Ultra sub out and I tried WiiM room correction varying the sub crossover in the APP but also with the crossover off and using the sub crossover.

I assumed initially the iPhone mike may not be able to accurately measure the lower frequencies, but then again, I used the iphone dB APP to set the sub volume equal to the mains using a stereo test album.

I am going to bring out my trusty Radio Shack dB meter and measure the output with the iPhone, the USB mike, and the Radio Shack and see if they all agree.

 

[jed1]

I use the Ultra sub out and I tried WiiM room correction varying the sub crossover in the APP but also with the crossover off and using the sub crossover.

I assumed initially the iPhone mike may not be able to accurately measure the lower frequencies, but then again, I used the iphone dB APP to set the sub volume equal to the mains using a stereo test album.

I am going to bring out my trusty Radio Shack dB meter and measure the output with the iPhone, the USB mike, and the Radio Shack and see if they all agree.

KEF KC62 may already have taken care of latency and feed right amount of delay to the main for typical configuration (sub at the middle between the mains or one side of mains). WiiM Ultra needs to be set up manually for latency and phase/polarity.

 

[Dennis from Venice]

I fiddled with latency with both the mains and the sub settings.....it had little difference

 

[slartibartfast]

I fiddled with latency with both the mains and the sub settings.....it had little difference

If you measure the response around the crossover frequency you should see it changing.