Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Equipment & Tools From test equipment to hand tools

DIY Audio Analyzer with AK5397/AK5394A and AK4490
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 14th February 2018, 12:39 PM   #1881
cwtim01 is offline cwtim01  Hong Kong
diyAudio Member
 
cwtim01's Avatar
 
Join Date: Aug 2012
Quote:
Originally Posted by Ghianni View Post
On the specification page of the RTX6001 unit there were mentioned figures of THD, THD+N, seen on the attached jpg. I assume that these measurements have been taken using audio-Tester V3. Would you please define the full setup applied to the SW and the unit of receiving these results?
Try the following (make sure your calibration is correct for each Input position):
  • THD@0dBV - Output:20dBV, Input:10dBV, Generator:-20dBFS. I get -124dB@48k and -120dB@192k (left channel)
  • THD@10dBV - Output:20dBV, Input:20dBV, Generator:-10dBFS. I get -120dB@48k and -120dB@192k (left channel)
  • THD+N@0dBFS - I find it strange the THD+N is specified for 0dBFS, cause 0dBFS will have high distortion whatever the attenuator position. But the THD+N spec of -107dB is easily reachable with Output:0dBV, Input:0dBV, Generator:-0.2dBFS. I get -109dB@48k and -109dB@192k (left channel)
My right channel is always 2-3dB worse than the left channel.
  Reply With Quote
Old 14th February 2018, 04:08 PM   #1882
lemon is offline lemon  Greece
diyAudio Member
 
Join Date: Apr 2009
Quote:
Originally Posted by cwtim01 View Post
If you only display the vertical scale in dBFS, there is no need to calibrate at all, dBFS is by definition relative.

Calibration is required, when you display the vertical scale in dBV (or dBU, ... etc.), and a different calibration value is required for each attenuate position, or else you'll get wrong values.
OK, I accepted it but the same happens and with dBV scale!
For example, I feed the left 0dBV input with -3dB signal at 1dBV output. This signal is 707mVrms.
If I calibrate the ARTA input with this value (707mV) and press the "Estimate" of input, then I will have a capture with the level threshold of -3dBV. I think this is OK, because the feed signal was -3dB.

Loop-back, -3dB sig, 0dBV input.png

If I returned the input knob to the 10dBV I will have -13dBV, that it is right...and so on with other scales.
Am I right or something has gone to my head?

Loop-back, -3dB sig, 10dBV input.png
Loop-back, -3dB sig, 20dBV input.png
  Reply With Quote
Old 14th February 2018, 04:08 PM   #1883
Ghianni is offline Ghianni  Greece
diyAudio Member
 
Join Date: Sep 2005
Quote:
Originally Posted by cwtim01 View Post
Try the following (make sure your calibration is correct for each Input position):
  • THD@0dBV - Output:20dBV, Input:10dBV, Generator:-20dBFS. I get -124dB@48k and -120dB@192k (left channel)
  • THD@10dBV - Output:20dBV, Input:20dBV, Generator:-10dBFS. I get -120dB@48k and -120dB@192k (left channel)
  • THD+N@0dBFS - I find it strange the THD+N is specified for 0dBFS, cause 0dBFS will have high distortion whatever the attenuator position. But the THD+N spec of -107dB is easily reachable with Output:0dBV, Input:0dBV, Generator:-0.2dBFS. I get -109dB@48k and -109dB@192k (left channel)
My right channel is always 2-3dB worse than the left channel.
I have nothing to add to your suggestions. The graphs speak for themselves.

My channel difference is at them most 1-2 dB.
Attached Images
File Type: jpg RTX6001_test_14_02_2018_11.jpg (117.7 KB, 65 views)
File Type: jpg RTX6001_test_14_02_2018_12.jpg (121.5 KB, 60 views)
File Type: jpg RTX6001_test_14_02_2018_21.jpg (119.4 KB, 48 views)
File Type: jpg RTX6001_test_14_02_2018_22.jpg (124.0 KB, 44 views)
File Type: jpg RTX6001_test_14_02_2018_31.jpg (112.0 KB, 43 views)
File Type: jpg RTX6001_test_14_02_2018_32.jpg (120.4 KB, 45 views)
  Reply With Quote
Old 14th February 2018, 05:45 PM   #1884
zfe is offline zfe
diyAudio Member
 
Join Date: Dec 2014
Quote:
Originally Posted by lemon View Post
OK, I accepted it but the same happens and with dBV scale!
For example, I feed the left 0dBV input with -3dB signal at 1dBV output. This signal is 707mVrms.
If I calibrate the ARTA input with this value (707mV) and press the "Estimate" of input, then I will have a capture with the level threshold of -3dBV. I think this is OK, because the feed signal was -3dB.

Attachment 662490

If I returned the input knob to the 10dBV I will have -13dBV, that it is right...and so on with other scales.
Am I right or something has gone to my head?

Attachment 662491
Attachment 662492
No you are perfectly right. But for doing so you need to think and not only to read.
This might be more sensitive for errors, moreover the needed extra information might not be available if you read the graph a week later, or so.

What is more appropriate depends probably on the context e.g. if you are only experimenting or do some documentation (but in the later case noting also the settings of the instrument would make that even more useable).
  Reply With Quote
Old 14th February 2018, 06:50 PM   #1885
mbrennwa is offline mbrennwa  Switzerland
diyAudio Member
 
mbrennwa's Avatar
 
Join Date: Mar 2005
Location: Zurich, Switzerland
Quote:
Originally Posted by zfe View Post
No you are perfectly right. But for doing so you need to think and not only to read. This might be more sensitive for errors...
Is this a joke? I don't think that reading without thinking is less sensitive to errors than combining the two. But maybe there is an error in my thinking
__________________
[ audioroot.net | hifibau.ch ]
  Reply With Quote
Old 14th February 2018, 08:19 PM   #1886
DualTriode is offline DualTriode  United States
diyAudio Member
 
Join Date: Aug 2009
Location: Sacramento
Default Funny in a sad way.

Funny in a sad way.

All this reminds me of my mother in-law’s dressmaker’s tape measure. Over the years of rolling and unrolling this thing it stretched. Hardly a standard of measurement but it worked for her. One day she was angry when she measured the yardage she had just purchased. She was unable to understand that it was her tape measure that was the problem.

DT

Last edited by DualTriode; 14th February 2018 at 08:23 PM. Reason: spelling
  Reply With Quote
Old 15th February 2018, 12:15 AM   #1887
cwtim01 is offline cwtim01  Hong Kong
diyAudio Member
 
cwtim01's Avatar
 
Join Date: Aug 2012
Quote:
Originally Posted by lemon View Post
... because the feed signal was -3dB ... If I returned the input knob to the 10dBV I will have -13dBV, that it is right...
If you use a DMM to measure a known 707mVrms (-3dBV) signal, and the DMM reads 0.223mVrms (-13dBV), what would you think?

And it seems you're OK when RTX+ARTA does exactly that.

Quote:
Originally Posted by lemon View Post
... something has gone to my head?
Apparently despite changing the vertical scale to dBV (which is absolute), your mind is still thinking in dBFS (which is relative).

Last edited by cwtim01; 15th February 2018 at 12:17 AM.
  Reply With Quote
Old 15th February 2018, 01:40 AM   #1888
cwtim01 is offline cwtim01  Hong Kong
diyAudio Member
 
cwtim01's Avatar
 
Join Date: Aug 2012
Oops, typo in my above post should read 223mVrms instead of 0.223mVrms.
  Reply With Quote
Old 15th February 2018, 07:56 AM   #1889
firev1 is offline firev1  Singapore
diyAudio Member
 
Join Date: Oct 2011
Location: Singapore
Default Crosstalk

Hello peeps, like you guys, I was somewhat frustrated with crosstalk issues despite Jensh's really great work. Excellent for single channel measurements. Used some 3M Ultraperm tape I had lying around.

Heres a measurement, sadly I forgot to screenshot the before measurements but you guys can measure that. I guess the next work is to try to reducing power supply harmonics somehow but I ran out of tape.

1st pic Setup is
Left input no input set to 0dbV
Right input connected to Right Output
Both Outputs putting out -3dbV signal

2nd pic Setup is
Left input no input set to 0dbV
Right input connected to Right Output
Both Outputs putting out 17dbV signal

Both are measuring the Left channel(worse case) inputs

Theres still some crosstalk which would be from the chip as Jensh has covered but its worth trying as others have done.
Attached Images
File Type: png no crosstalk.png (22.5 KB, 80 views)
File Type: png crosstalk2.png (22.8 KB, 77 views)
File Type: jpg DSC_0411.JPG (112.1 KB, 116 views)

Last edited by firev1; 15th February 2018 at 07:58 AM.
  Reply With Quote
Old 15th February 2018, 08:36 AM   #1890
Ghianni is offline Ghianni  Greece
diyAudio Member
 
Join Date: Sep 2005
@firev1
What's the height of the shield panels?
  Reply With Quote

Reply


DIY Audio Analyzer with AK5397/AK5394A and AK4490Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
New AKM Stereo ADC AK5397 announced JensH Digital Source 20 24th December 2014 12:05 PM
New AKM Stereo ADC AK5397 ??? HpW Equipment & Tools 6 16th May 2014 04:26 PM
NTi Audio XL2 Handheld Audio Analyzer Fredenando Equipment & Tools 0 18th April 2010 03:04 AM
AKM AK5394a TobWen Digital Source 41 31st December 2003 06:18 PM


New To Site? Need Help?

All times are GMT. The time now is 01:28 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki