All times are UTC+02:00




Post new topic  Reply to topic  [ 14 posts ]  Go to page 1 2 Next
Author Message
PostPosted: Mon Mar 15, 2021 2:10 am 

Joined: Sat Jul 04, 2015 10:40 pm
Posts: 7
StereoTool is among the most useful software packages I use. I am impressed at the innovation & brilliant problem solving skills of Hans. Few engineers have impressed me as much! However, I'm a bit fuzzy on how the TILT is used in the declipper. Perhaps it is the short explanations when you mouse over the interface features that are confusing me? I'm not sure. However, I have had good experiences with the declipper - although an in-depth video tutorial would be helpful. Especially - TILT. I routinely observe audio on the scopes that clearly is clipped and tilted - and even with good declipper results - this form of clipping is still prevalent in some of my music & I think the solution lies in a better understanding of HOW the available controls in ST can be used to declip a tilted section of audio. Any suggestions or references?


Top
   
PostPosted: Sat Mar 27, 2021 1:43 pm 

Joined: Tue Jul 02, 2019 7:20 am
Posts: 6
Tilting depends not only from the software which you are using to fix your audio. It depends from another critical factor which is your transmitter and especially your pll. A good pll with dual speed loop is a good start in order to get rid the annoying tilt.


Top
   
PostPosted: Tue Mar 30, 2021 8:39 pm 
Site Admin
User avatar

Joined: Mon Mar 17, 2008 1:40 am
Posts: 10270
Hi, sorry for the slow response. What tilt basically does is, it tries to de-tilt the audio before detecting clipping. As you can see in many files, if a tilt has been introduced after clipping, then detecting clipped audio is no longer a matter of just finding samples at the same (and highest) level, but instead you need to tilt the audio first to make those peaks flat.

It's a bit hard to explain, the default settings were created based on some worst-case recordings. But there may be even worse out there that we haven't seen.

To get an idea what tilt does, you can use the RC slider for the FM output and check what it looks like on clipped audio or on square waves. The de-tilt filter basically tries to find the best RC value match for every piece (a few dozen ms) of audio.


Top
   
PostPosted: Wed Mar 31, 2021 5:25 am 

Joined: Tue Jul 02, 2019 7:20 am
Posts: 6
Hans lets suppose that we use the rc correction in order to eliminate tilting of transmitter and we do this successfully, but I'm wondering if this action influence the quality of audio which produce our sound card.


Top
   
PostPosted: Wed Mar 31, 2021 5:58 am 
User avatar

Joined: Tue Mar 17, 2009 2:56 pm
Posts: 3762
Quote:
Tilting depends not only from the software which you are using to fix your audio. It depends from another critical factor which is your transmitter and especially your pll. A good pll with dual speed loop is a good start in order to get rid the annoying tilt.
He was asking about Tilt in Declipper and that has nothing with outputs HD or FM.
Tilt is simple. It occures in every analog path, input or output. Even if you have one analog ideal output, like all say Marian Trace soundcards, in our applicatioons we need to attach it to transmitter MPX input. And that input is not ideal, so again need some Tilt adjustment to be perfect anyway.

For good DeClipping only one thing is needed, good input tilt. I think ST is only program that has Input Tilt adjustment (standoalone), wich is ideal for analog inputs. DeClipper internaly also looks for already clipped and then tilted tracks up to 45deg by default. So probably meets 99.9% tracks that exist. So DeClipper basically by default can be just turned ON and forget about it.

Manually adjusting for specific track is possible by using input Tilt and watching scope to make tilt fine so Declipper can do it's job easier.

_________________
control point


Top
   
PostPosted: Wed Mar 31, 2021 6:15 am 

Joined: Tue Jul 02, 2019 7:20 am
Posts: 6
Quote:

For good DeClipping only one thing is needed, good input tilt. I think ST is only program that has Input Tilt adjustment (standoalone), wich is ideal for analog inputs. DeClipper internaly also looks for already clipped and then tilted tracks up to 45deg by default.
Hi Bojcha.
How we could adjust the input of st ? Like tilting on fm output? By producing square wave of 60hz and trying to optimize with rc correction of input?


Top
   
PostPosted: Wed Mar 31, 2021 5:18 pm 
User avatar

Joined: Tue Mar 17, 2009 2:56 pm
Posts: 3762
Quote:
Quote:

For good DeClipping only one thing is needed, good input tilt. I think ST is only program that has Input Tilt adjustment (standoalone), wich is ideal for analog inputs. DeClipper internaly also looks for already clipped and then tilted tracks up to 45deg by default.
Hi Bojcha.
How we could adjust the input of st ? Like tilting on fm output? By producing square wave of 60hz and trying to optimize with rc correction of input?
Input tilt, just play 30-60Hz Squere tone from your usuall source/player/playout, go to ST and watch input scope.. horizontal lines should be 100% horizontal. And this is only if your ST input is Analog. With digital/network/etc input should be already ideal, i anyway always check. ;)

Output FM Tilt is same but bit tricky, You need to have really good tool to measure that squere tone from your transmitter, from AIR. Erlier I used my Kenwood tuner with MPX output to my USB 192kHz soundcard. All that calibrated with Rohde-Schwarz Unit - Tilt and MPX level.
Now it's waaay easier for me since u use MPXtool with SDR.
You can also do it with Pira.. play squere tone and tune Output Tilt so MPX output level need to be lowest as possible, meaning horizontal line is ~100% horizontal

_________________
control point


Top
   
PostPosted: Thu Apr 01, 2021 4:36 am 

Joined: Tue Jul 02, 2019 7:20 am
Posts: 6
Thank you Bojcha for these details. I have tried to optimize the input of st with rc correction by producing square wave of 60hz from my laptop which is my source, but on the scope of st i couldn't see a normal square with horizontal lines.
Regarding tilt on output i' m using pira analyzer but before feed with my mpx the transmitter i make rc correction with my oscilloscope. The problem after this action is that transmitter needs different rc correction in order to achieve the minimum tilt of mxp on air.


Top
   
PostPosted: Thu Apr 22, 2021 7:15 am 

Joined: Thu Sep 13, 2018 10:14 pm
Posts: 15
In my experience tilt might not work correctly, unless this has been changed in the past year without any mention in the update notes. See here: viewtopic.php?f=15&t=28287


Top
   
PostPosted: Sat Jul 10, 2021 7:13 pm 

Joined: Sat Feb 21, 2015 10:53 pm
Posts: 20
Quote:
Hi, sorry for the slow response. What tilt basically does is, it tries to de-tilt the audio before detecting clipping. As you can see in many files, if a tilt has been introduced after clipping, then detecting clipped audio is no longer a matter of just finding samples at the same (and highest) level, but instead you need to tilt the audio first to make those peaks flat.

It's a bit hard to explain, the default settings were created based on some worst-case recordings. But there may be even worse out there that we haven't seen.

To get an idea what tilt does, you can use the RC slider for the FM output and check what it looks like on clipped audio or on square waves. The de-tilt filter basically tries to find the best RC value match for every piece (a few dozen ms) of audio.
Hey Hans, in the Metallica Album Death Magnetic, if you zoom in on the waveform, the signal is not only heavily clipped, but you can also see a very clear tilt downward of around 15 degrees in the flat peaks across say 100 samples. Is this what you are talking about? If so, when I get back home I can upload an image of it. BTW, What the heck plugin would have caused that in the mastering stage when they made that fatiguing album?


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 14 posts ]  Go to page 1 2 Next

All times are UTC+02:00


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Limited