Beta Test: Multitone Loopback Analyzer software

[Rantapossu]

Let's wait for 2 more guesses to continue to the next step of the reveal... Anyone else?

 

[Moto]

In my case, which I think Sokel has in mind, it is how to do very low level measurements and know what the results really mean. In the spectrum graph of a single tone, the level shown is 6.02 db lower than expected. So at a minimum all I can say is if I adjust for that 6.02 db then the results are at the levels expected vs Full Scale. I more or less confirmed it works and Sokel did a test that appears to confirm it as well. It also agrees with what is shown in the results tabulation if you open it from the square near the upper right corner.

I have a guess as to why this is, but only pkane can confirm it or explain how I am misinterpreting the results shown.

If I didn't answer what you were asking, then be a bit more specific and I'll explain it as far as I can.

Thx. I think I follow your adjustments but don't understand why they are happening.

 

[Blumlein 88]

Thx. I think I follow your adjustments but don't understand why they are happening.

I'm not sure either. My earlier guess is related to FFT's. FFT's have a positive and negative component. As long as there is no DC shift, it is fine to discard the negative portion and plot the spectrum with the positive half of the FFT. Doing so means the signal will display with half the amplitude. It is suggested you simply double amplitudes to get the correct readout in terms of amplitude. Doubling amplitude is the same as increasing it 6.02 db. For most of the tests you would run you can select dbR in the settings, and it will reference everything to the highest amplitude tone which makes it a non-problem.

I'm not knowledgeable enough about the various processing going on inside Multitone to know if there is a good reason not to raise the amplitude displayed. It may simply be that Multitone doesn't block or remove DC and other factors make it a bad idea to double the displayed amplitude.

 

[Sokel]

Let's wait for 2 more guesses to continue to the next step of the reveal... Anyone else?

C-O-S-M-O-S!
Measure it until it drops!

 

[Sokel]

Thx. I think I follow your adjustments but don't understand why they are happening.

That's the practical side.
Since we figured out the exact levels we can adjust accordingly.
As to why levels appear that way (in dbfs) @pkane can explains us sometime.
It did some test after the first ones and it's nice and constant so it's easy to adjust.

 

[Rantapossu]

Cosmos ADC?

C-O-S-M-O-S!
Measure it until it drops!

2 down, 1 to go!

Let's wait for the third guess...

 

[Sokel]

I think I found E-mu's sweet spot.

dbfs

dbr

 

[Sokel]

Is there a way to measure DSD signal?
Must be external I suppose.
Good luck finding one,and the SACD converter doesn't work when I point it to convert a pcm one.

 

[Sokel]

Ok,I found one,let's see...

 

[Sokel]

Let me ask something...
Does system (sound properties) volume affects ASIO?
It shouldn't I think...
Yet it does.

Edit: it affects only playback device,not mic,regardless the setting of "Set System Volume".

 

[pkane]

I'm not sure either. My earlier guess is related to FFT's. FFT's have a positive and negative component. As long as there is no DC shift, it is fine to discard the negative portion and plot the spectrum with the positive half of the FFT. Doing so means the signal will display with half the amplitude. It is suggested you simply double amplitudes to get the correct readout in terms of amplitude. Doubling amplitude is the same as increasing it 6.02 db. For most of the tests you would run you can select dbR in the settings, and it will reference everything to the highest amplitude tone which makes it a non-problem.

I'm not knowledgeable enough about the various processing going on inside Multitone to know if there is a good reason not to raise the amplitude displayed. It may simply be that Multitone doesn't block or remove DC and other factors make it a bad idea to double the displayed amplitude.

It is a factor of 2x (or 6db) difference due to only positive frequencies being counted. I'll see if it makes sense to correct for it.

 

[pkane]

Let me ask something...
Does system (sound properties) volume affects ASIO?
It shouldn't I think...
Yet it does.

Edit: it affects only playback device,not mic,regardless the setting of "Set System Volume".

DSD output should not be affected by any system settings if you use a true ASIO driver and not one that routes audio through WASAPI or other audio interfaces.

 

[Sokel]

DSD output should not be affected by any system settings if you use a true ASIO driver and not one that routes audio through WASAPI or other audio interfaces.

No,I'm talking about PCM with MT own signals.
I'm not able to test DSD,it's output is too hot for E-MU.

 

[pkane]

No,I'm talking about PCM with MT own signals.
I'm not able to test DSD,it's output is too hot for E-MU.

Oh, you're talking about MT not resetting mic input level. Something I've had no problems with, but I can certainly look into setting mic input level, as well.

 

[Sokel]

Oh, you're talking about MT not resetting mic input level. Something I've had no problems with, but I can certainly look into setting mic input level, as well.

No,no,I'm saying that I can control output volume through windows system properties even during a measurement while being in ASIO.
I think I couldn't do that in previous versions.
Mic is not affected,I tried.

 

[Rantapossu]

No,no,I'm saying that I can control output volume through windows system properties even during a measurement while being in ASIO.
I think I couldn't do that in previous versions.
Mic is not affected,I tried.

I think that the Windows system playback volume has always affected to the E-MU ASIO output volume. Recording level doesn't affect to ASIO for me too.

 

[Sokel]

To make it easier.
Look above at my previous measurement,output is at -2.09db with -6db play gain (that's 100% volume of Khadas)
At the below one I set the volume at 77% in windows mixer and the output is the same with -2db play gain.

 

[Sokel]

I think that the Windows system playback volume has always affected to the E-MU ASIO output volume. Recording level doesn't affect to ASIO for me too.

Thing is that the output is Khadas,not E-MU.
Not in other versions,believe me I have tried to match the outputs with play gain and it wouldn't let me,MT was in charge.
Now I can (and I don't know what is correct,it's handy this way but I had to report!)

 

[Rantapossu]

Thing is that the output is Khadas,not E-MU.
Not in other versions,believe me I have tried to match the outputs with play gain and it wouldn't let me,MT was in charge.
Now I can (and I don't know what is correct,it's handy this way but I had to report!)

Your highest harmonics

look a lot like my left channel spikes (Caused by the improper traces and component locations on the PCB):

My right channel is a lot cleaner there.

You said earlier that you tried with the right input channel of the E-MU too, but are you sure that you have two identical channels?

Please try Khadas (Right) -> E-MU (Right) again if you have time...

 

[pkane]

Thing is that the output is Khadas,not E-MU.
Not in other versions,believe me I have tried to match the outputs with play gain and it wouldn't let me,MT was in charge.
Now I can (and I don't know what is correct,it's handy this way but I had to report!)

If it's using an ASIO driver, MT is not in control -- the output should be going directly to the audio card at the generated play gain with no changes made by Windows. There is no way that MT can cause ASIO to route through the Windows volume control, unless the output is somehow going to the WASAPI or DS driver, instead.