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Stereo Tool 7.20 Release

Listening at work (Genelec monitors) it didn't sound as bad as @home but I still prefer the Multiband Off. I've uploaded a file where on/off test was recorded. The sound if from the BBC Radio2 stream, wich has a conservative processing, recorded onto Dalet then converted to mp3 and uploaded.

http://soundcloud.com/u-topico/stereotool7-24

Starts with the Multiband On, then here and there I turn it on/off. ON is when the bass is deeper, the loudness larger as well the clipping.
 
I don't know how much SoundCloud added to it, but the quality of that recording is really bad (lots of MP3 artifacts, and indeed some weird phasing). Which I already feared when you described the signal path (processing, then MP3 encoding, decoding, another MP3 encoding step, and then processing again).

The multiband compressor usually enhances softer sounds. Now in case of a bad MP3 with MP3 artifacts, it will enhance those. What MP3 encoding does is throwing away information that it "thinks" you cannot hear - any change made to the signal afterwards (for example by processing) can cause such artifacts to be blown up and become very audible. I can also tell you that bad quality MP3s are much harder to clip than good quality audio.

In this situation I should probably ask why you are re-processing this signal?
 
I forgot to add... I'm aware of stream audio weaknesses.
Despite that I've still chose to record a station with a very slight conservative native processing and pass it through ST (BBC radio2). That's why...


SFM-Ptgal said:
http://soundcloud.com/u-topico/stereotooldm

Here you have a wav, from a wav recording...

Preset: FM Transmitter

Starts in bypass

@12'' Multiband is turned ON, after a while I start decreasing the cliper driver from the Advanced Clipper...
Click to expand...




I
 
I still hear pretty bad MP3 encoding artifacts - SoundCloud only seems to stream audio, as far as I can see I cannot download the .wav file that you uploaded. Also the processed signal probably already used a phase rotator which can lead to strange results, especially (!) if you're using the old multiband which - based on what you wrote - you seem to be doing (the newer User presets use the new and greatly improved multiband compressor, the old one is only still there for backward compatibility, I don't want to force people to create a new preset when they update to the latest version, and it's by default hidden).

I should probably remove the presets on the top of the list and only keep the user presets.
 
I'm running v7.24. The multiband is from that version.
Listening to the users presets there are nice ones with the multiband on.

Side note: at home I'm running ST on Linux Mint KDE, AMD 3.6 DCore, 4gigs, and the the cpu shows around 85-100% while running ST via Jack. Reaching 100% it stops. Soundcard is an old SBLive ;D
No complaint intended here.

I have a fellow engineer who's amazed by the software. I'm not one and I'm too ;)
 
I have a problem something like that also. The chain: mixer, Stereo Tool with phase rotator and multiband and quiet processing then stream (MP3, so not fantastic) and this stream I put in another Stereo Tool with phase rotator at the transmitter site. This situation isn't actual yet, so I am testing this with another transmitter. Have switched of the multiband of the second Stereo Tool, that sounds already better. I know uncompressed without processing to the Stereo Tool at transmitter site is the best, but not possible (yet). Makes it sense to switch off the phase rotator in the first Stereo Tool? After the stream the signal goes to cable broadcaster, so I can't remove the first Stereo Tool. I have tested also with a higher bitrate stream and that is a bit better, but still artifacts in the sound.
 
@Edgar: You don't want to repeat things - so definitely don't use 2 phase rotators - it won't improve anything and may cause artifacts.

Basically, in your situation, at the transmitter site only perform those steps that you haven't done already in the studio. The good news here is that there are no dependencies between processing filters in Stereo Tool, you only need to perform them in the correct order (after all, it doesn't make much sense to use an AGC after a multiband compressor etc.). So if you look at the list of filters, make a cut where you perform everything above the cut at the studio, and everything below the cut at the transmitter site.

So my suggestion for your situation:
* Studio: Declipper, noise gate, AGC, stereo enhancement, equalizer, multiband, band pass, phase shaping, bass boost, phase rotation, singleband.
* Transmitter: ONLY Advanced Clipper, Hard Limit, FM (pre-emphasis, ...).

Now since you need to avoid overshoots in the stream, you'll also need to use some clipping in the studio output. Just make sure it doesn't clip too much. So, enable Advanced Clipper there as well but lower the Drive.

Finally, assuming that you're starting from a good preset, make sure to choose the same preset at both locations. And you need to adjust the Pre Amplifier at the transmitter site to make sure that the volume that goes into the Advanced Clipper there is identical to what you would have if there was no stream in between.

How to do this: There are 2 things in the studio output that cause a change in the level:
- Advanced Clipper drive
- Post Amplifier

Say Advanced Clipper drive is set to 0.60 and Post Amplifier to 0.80. Then the total adjustment is 0.60*0.80 = 0.48. Which means that you need to compensate using the Pre Amp at the transmitter, by setting it to 1/0.48 = 2.08.


Since you're basically only clipping at the transmitter site, the MP3 artifacts from streaming will not be increased much.
 
I am very close to building a ST processor to use on air. Will keep you posted.
 
All you Big Mac lovers stroll on over to the ST site and download the Mac ST software. New 7.25 release coming shortly for all platforms. That Hans is a mess!!!
 
Beta 7.25-023 up and it is a killer.Download now and enjoy, this almost makes other versions obsolete. A couple of killer presets on the way.Rock it!!
 
My 7.24 is on the air and is a very interesting sounding processor! I did not see any beta 7.25-023 anywhere and I think I'll wait until it is debugged before I try it.

My only real complaint about ST is the shortage of up-to-date documentation. Finding out what does what is frequently hit-and-miss.
 
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