REW first scan - mystery

[Keith_W]

This is the UMIK-1 with 0º pointed at MacBookPro screen from 30cm using MacBook's left speaker.
It does not show the cliff-shape response that I got with hifi / F206 speakers measurement.

I will try the other suggestions from contributors in turn.
I just need a bit of time as not very familiar with these things.


Does this show the UMIK-1 is working correctly?

Ha! Did you use a different cal file for the 0deg measurement?

 

[1066]

Or he can just upload it here.

These are the UMIK-1 download files.

 

[1066]

Ha! Did you use a different cal file for the 0deg measurement?

I swapped to the calibration file which does not have _90deg in the title for the macbook's own speaker test.

I wanted to see if UMIK-1 would measure up to 20khz from a different speaker output other than main system...

It does seem to.

 

[Keith_W]

Well I opened up both the cal files to take a look. In short - not the cal file.

There are some very strange things going on here, so let's review what we have so far.

- OP says he can hear that the treble is missing. This is confirmed by listening to test tones.
- Measurement of main speakers with UMIK1 oriented vertically shows treble cut-off at 5kHz (L channel) and 8kHz (R channel) with the noise floor at -140dB to the main speaker level. This is basically impossible which points to a defective mic.
- Measurement of Macbook speakers with the mic oriented horizontally shows expected behaviour of the microphone.

I guess the next step is to measure the Revels with the mic pointed horizontally.

 

[1066]

Yep.

View attachment 436720

just edit it, add couple of zeros beside the 11.1 and you're ok.
Same all the way down,there's others missing too.

All the values need to have 3 decimal places filled.

ok will look through and save .txt files.

 

[RayDunzl]

Mic test:

RTA of a single hand-clap a few inches from the mic.

Red is peak levels.

Obviously a wideband signal. and not dependent on any other equipment.

 

[1066]

All the values need to have 3 decimal places filled.

ok will look through and save .txt files.

Yikes!
There are many rows of numbers...

 

[Sokel]

All the values need to have 3 decimal places filled.

ok will look through and save .txt files.

No,no, scrap what I said,I was looking at the wrong thing, they look ok down there. But it's still strange when loading them to REW.

 

[1066]

No,no, scrap what I said,I was looking at the wrong thing, they look ok down there. But it's still strange when loading them to REW.

Ah ok.

 

[1066]

Will look through messages for other things suggested to try - back later.

Thank you all for your time and knowledge, very much appreciated.

 

[1066]

There's something else to check too as in an acoustic measurement like that the level shown there is crazy and I suspect the mic.
While mic is connected just hit the RTA window at REW and show it to us.

Normally it should show your room's noise floor.

This is screenshot of RTA just now.

 

[staticV3]

@1066
I'd focus on the very real issue of missing treble response out of your Revels first.

Your reports so far suggest an issue with the SU-9, since treble is missing no matter if you send audio to it via USB from your MacBook, Bluetooth from an iPhone, or Toslink from the WiiM.

Next step should be to try another DAC. If the problem is gone, then you have your culprit.

You can plug RCA DACs or 3.5mm DACs like the MacBook into your Amp's XLR input with the right cables.

All the UMIK stuff can come later.

 

[Sokel]

This is screenshot of RTA just now.

That looks about right.
Does it respond to noise (a hand clap) the way @RayDunzl shows?

 

[1066]

@1066
I'd focus on the very real issue of missing treble response out of your Revels first.

Your reports so far suggest an issue with the SU-9, since treble is missing no matter if you send audio to it via USB from your MacBook, Bluetooth from an iPhone, or Toslink from the WiiM.

Next step should be to try another DAC. If the problem is gone, then you have your culprit.

You can plug RCA DACs or 3.5mm DACs like the MacBook into your Amp's XLR input with the right cables.

All the UMIK stuff can come later.

Have found SMSL M8 in a drawer and a couple of cables which may have right connector?
Is it safe to connect to the Nord 2 balanced inputs using this type of cable?

 

[sam_adams]

What could it be?

The response posted:

Looks oddly similar to that posted in this discussion in the REW support forum on AV Nirvana:

Which, as I posted earlier, was caused by the DAC muting the output when one channel has no signal. Output to both L+R simultaneously and disconnect the DAC output for that channel that you are not measuring.

 

[staticV3]

Is it safe to connect to the Nord 2 balanced inputs using this type of cable?

Here's the cable pinout you want for RCA->XLR:


You can check your own cable with the continuity (beeper) function of your multimeter.

 

[1066]

The response posted:
View attachment 436736

Looks oddly similar to that posted in this discussion in the REW support forum on AV Nirvana:

View attachment 436738

Which, as I posted earlier, was caused by the DAC muting the output when one channel has no signal. Output to both L+R simultaneously and disconnect the DAC output for that channel that you are not measuring.

oh my goodness!

They look very similar.

 

[1066]

Here's the cable pinout you want for RCA->XLR:
View attachment 436740

You can check your own cable with the continuity (beeper) function of your multimeter.

Thank you. Will check.

 

[1066]

Here's the cable pinout you want for RCA->XLR:
View attachment 436740

You can check your own cable with the continuity (beeper) function of your multimeter.

Have ordered cable from Amazon.
The rca>balanced cables I have are female unfortunately.

Thank you all, I’ll try again tomorrow.

 

[1066]

The SMSL M8 DAC has replaced SMSL SU-9 DAC.
The signal is via Airplay* > WiiM mini > Optical > SMSL M8 > ICE 1200 amplifier > Revel F206.
I did not get the result I expected.


REW says signal too low (see screenshot).
It sounds quite loud to me though, via speaker.
I checked the loudness with my iPhone (mic towards speaker) to see if it was similar to the UMIK-1 reading in REW for level. Screen shot attached.
I pressed 'Measure' in REW anyway.
I have made a measurement at 0º Left speaker.

Q. What test noise loudness is needed for REW measurement?

I can go a bit louder during the day if I'm nearly at measurement level - I'm in UK terraced house - so in the evening I have levels lower for neighbours.

I guess the SU-9 DAC is ok, as it has been swapped with M8 and a similar result showing.


*missing a USB 2.0 > C adaptor at moment