New WIIM Ultra, Steep Cutoff at 15khz, Firmware Updated, EQ Off

[Jmdesignz2]

My WiiM ultra which I just purchased last week is showing a steep cutoff at slightly above 15khz

I looked for firmware updates and it is updated

EQ is off, 24/192 Coax to Fosi ZD3 DAC, XLR output to V3 Monoblocks

This cutoff shows up in repeated frequency response test in REW

I filed a ticket yesterday. Seeing if anyone else is having this issue

showing up when I use REW with a calibrated UMIK microphone, new Philharmonic BMR Towers (RAAL tweeters)

 

[slartibartfast]

My WiiM ultra which I just purchased last week is showing a steep cutoff at slightly above 15khz

I looked for firmware updates and it is updated

EQ is off, 24/192 Coax to Fosi ZD3 DAC, XLR output to V3 Monoblocks

This cutoff shows up in repeated frequency response test in REW

I filed a ticket yesterday. Seeing if anyone else is having this issue

showing up when I use REW with a calibrated UMIK microphone, new Philharmonic BMR Towers (RAAL tweeters)

Have you tried without the Fosi DAC?

 

[Jmdesignz2]

Have you tried without the Fosi DAC?

Just ran two tests- RCA analog output direct from Wiim Ultra, Same Result

 

[slartibartfast]

Just ran two tests- RCA analog output direct from Wiim Ultra, Same Result

Strange. Did the sweep signal definitely cover the full frequency range up to 20kHz?

 

[Jmdesignz2]

Strange. Did the sweep signal definitely cover the full frequency range up to 20kHz?

AFAIK I am running the standard sweep ootb REW. I tried each filter of the Wiim Ultra DAC with different results of roll off but same cut off at ~15kHz

 

[Jmdesignz2]

One of the filters gave me about 1db more dynamic range tho

 

[Jmdesignz2]

Strange. Did the sweep signal definitely cover the full frequency range up to 20kHz?

Yes I double checked the sweep range and it was set at 0 to 20khz. I am going to run another test with sweep 0 to 30kHz

 

[slartibartfast]

AFAIK I am running the standard sweep ootb REW. I tried each filter of the Wiim Ultra DAC with different results of roll off but same cut off at ~15kHz

How are you feeding the signal into the Ultra?

 

[Wiimer]

My WiiM ultra which I just purchased last week is showing a steep cutoff at slightly above 15khz

I looked for firmware updates and it is updated

EQ is off, 24/192 Coax to Fosi ZD3 DAC, XLR output to V3 Monoblocks

This cutoff shows up in repeated frequency response test in REW

I filed a ticket yesterday. Seeing if anyone else is having this issue

showing up when I use REW with a calibrated UMIK microphone, new Philharmonic BMR Towers (RAAL tweeters)

I was curious to find out.

I placed the microphone at a distance of 5 cm from the tweeter of my speaker to which the Ultra is connected, and played a 20-20k sweep.

As a result, my Ultra could play back up to 20k without any problems.


This is Amp Ultra.



At least my Ultra has no problems.

 

[Jmdesignz2]

How are you feeding the signal into the Ultra?

Macbook Pro running REW sending signal via Wifi link

 

[Wiimer]

Macbook Pro running REW sending signal via Wifi link

I guess the your Mac is not send signals above 15 kHz.

 

[slartibartfast]

Macbook Pro running REW sending signal via Wifi link

Are you using an acoustic timing reference in REW?

 

[slartibartfast]

Also you can run RoomFit using the UMIK-1 and compare the response to the REW result

 

[Jmdesignz2]

Figured it out- it was actually connecting by bluetooth which cuts off the signal at approx 16kHz

 

[GarthTheChicken]

Figured it out- it was actually connecting by bluetooth which cuts off the signal at approx 16kHz

Is this common to bluetooth? I’ve been connecting house curve to my pro plus like this as airplay seems intermittent and noticed a similar issue

 

[Jmdesignz2]

Is this common to bluetooth? I’ve been connecting house curve to my pro plus like this as airplay seems intermittent and noticed a similar issue

Yes, there are some different BT protocols and depending on what connects, you will get this cut-off. Best to use Wifi or wired connections

 

[Jmdesignz2]

I was curious to find out.

I placed the microphone at a distance of 5 cm from the tweeter of my speaker to which the Ultra is connected, and played a 20-20k sweep.

As a result, my Ultra could play back up to 20k without any problems.
View attachment 26228

This is Amp Ultra.
View attachment 26229


At least my Ultra has no problems.

actually - why is there such a steep cut off at 20kHz? Most tweeters extend further and don't have such a dramatic cut off

 

[hgo58]

actually - why is there such a steep cut off at 20kHz? Most tweeters extend further and don't have such a dramatic cut off

This the max frequency for the 44.1 kHz sampling. This is how digital sound works.

 

[mlsstl]

actually - why is there such a steep cut off at 20kHz? Most tweeters extend further and don't have such a dramatic cut off

Nice that some tweeters go past 20KHz. Pity that our ears don't....

 

[Wiimer]

actually - why is there such a steep cut off at 20kHz? Most tweeters extend further and don't have such a dramatic cut off

As @hgo58 said, it has to do with the type of source file and sampling rate. I played a 20Hz-20kHz sweep. (No sounds above 20 kHz are recorded.)

This is pink noise.


This is 192kHz Rat avoidance ultrasound.

My speaker was able to play 48 kHz noise. (The upper limit for this Android app is 48 kHz.)

Btw this is when nothing is playing.