Stereo Tool

If you use the same settings, Stereo Tool 3 performs better than 2.10. But Stereo Tool 3 has a lot of extra's:
- Multiband HQ mode is new, clipping is new, post filtering is new
- Loudness is new
- Dualband Pre-limiter is new
- Final pre-limiter and final limiter are new (replace the singleband limiter)
- All FM settings are new
- The AZIMUTH correction settings are not turned on in any of the Stereo Tool 2.10 presets

Looking at this test case:
Everything Turned on (Normal Quality): 27-32%
Loudness Slider to minimum: 24-25%
Untick HQ on Multiband:0-4%

If you would also untick the dualband pre-limiter and the final pre-limiter, and the multiband post filtering and clipping, and set both AZIMUTH sliders to 0, you should get even lower values - and clearly lower than those in Stereo Tool 2.10.

Note: I do know that using pre-emphasis without pre-emphasized output is currently taking more CPU power than necessary. I will look into that.

Yes, I've played without all the extras -- or only ticked a few of them in, like the final limiter.
It does great like that, no doubt! And you're right, it does better than 2.1.

Speaking of the final limiter .. is "x" a multiplier or threshold? And, is it set for an out of 0db?

Hi Tekie,

First of all, here's a beta-version of Stereo Tool 3.03, with a simpler interface (just click on "Basic mode" to switch to the simple interface):
http://www.stereotool.com/download/dsp_ ... r_BETA.exe

Basically, it does the same thing as the "Advanced mode" (which is the mode in versions 3.0-3.02), but some settings are adjusted automatically - you don't have to do it yourself anymore.

I need to test it further to be sure that I didn't introduce any new bugs (if you find any, please let me know).

"x" is indeed a multiplier - it sets the amplification before the final limiter starts working.

It is indeed set for an output volume of 0 dB, you can change that by changing the "Post Amp" slider. (Just set the Post Amp a bit lower and you will see that the volume does not get higher than a certain point).

Okay, I'll try it out later tonight and give a report tomorrow.

Not sure whats been done, but I think you've worked on the chimpmunks - thats good

Simpler interface is looking good.

I noticed something this time .. if I turn the pre-amp and post-amp to zero, the input level
meter still registers signal coming in. I suppose it's measuring input before it goes through
any processes. Also, I noticed in that position that the CPU doesn't change much on usage.
I suppose it's because the stages are active no matter if it's processing a signal or not.
If I had to guess, I would say that it's the buffering thats keeping the CPU at 30%.

Didn't notice any new bugs.

I'm not sure -- but, I think the pre-limiter has a problem. I turned it off and substituted
a stand-alone limiter just before Stereo Tool. I set it for 6db on threshold, 0db out and
set the pre-amp slider to 2.5.

These settings were basically equal in volume between the two. What I noticed, is that
the pre-limiter seems to have a duller sound -- it's not bad, just noticable. When I listened
to it with the stand-alone limiter -- it was definitely cleaner.

I'm not a computer programmer, so I have no idea how it's pinned out between stages.

I'm just giving my opinions and feedback. (which is worth about 2 cents)

I first started using 2.10 a year ago and liked how clean it sounded, however the old version didn't level the volume as well or allow (direct) equalization. This new version has good volume levelling (with pre-limiter), equalization and much more! IMO -- the less aggressive settings sound the best. Of course, broadcast audio processing is all about trade-offs between loudness and other aspects of perceived quality.

Great Job with this program!

If you look at the volume bars below the pre-limiter, the two bars should be about equal in volume. If the right bar is lower, set the right "soft limit" slider higher to achieve a brighter sound. This might cause the "duller" sound.

Note: When you use the separate limiter, can you check if in the multiband compressor the bars at the right (highs) are lower than those at the left?

The pre-limiter in Stereo Tool is a dualband pre-limiter. This means that, when a lot of high frequency sounds are present, they will be reduced more than the low frequency sounds. That might cause exactly what you are describing. If so, it's a "wanted" effect - it will keep the amount of treble more constant, and avoid excessive compression on the high frequencies. If that's not the case, there might be a problem.

By the way, with the input and output set to 0, all the processing is still being performed - only zeros are fed through it. That won't make things use less CPU power.

That does enhance the brightness of the sound a lot! Although I can't reach the brightness I'm looking for. If I raise the high sliders of the multiband compressor the sound becomes "unsteady" I don't know how to describe it better. And is it hard for you to transform this plugin into a VST plugin so I can reduce the latency? I'm testing with a Modulation Sciences MPX clipper and an 18 watt Suono mono transmitter. If you want me to try anything please let me know, I'll be pleased to do so. Further I can only say it's a real nice peace of software! Keep up the good work.

PS. The "Close" button in the Transmitter configure page doesn't work, but I guess you already know that.

Greetings

Diekgait

Couple quick questions -- what types of digital filter implementations are used in Stereo Tool (IIR Bandpass? What order? Are they phase linear, etc)? Also, how does the "loudness" control work internally? Of course if the answers are secret, I understand

Thanks

You might try using the equalizer for this... Is this happening when using FM pre-emphasis? Because in that case, the only thing you can really do is to reduce the amount of compression. The reason for this is that, when pre-emphasis is applied, the high frequencies are increased a lot (15 dB or so). Limiting will reduce the high frequencies more than the low frequencies, because they are so loud. (I could create a fix for that by the way, at the expense of loosing some of the volume).

A VST plugin is probably a good idea (I'm also planning to create a stand-alone version), but it probably won't help a lot with latency - all the processing that occurs also causes (a lot of) latency.

Oops - completely forgot that close button... Will fix that in a future version.

By the way - are you trying to get FM stereo sound with your mono transmitter? I have an intermediate version that makes that a lot easier. (No need to use annoying LineIn plugins etc.). Let me know if you want a copy of that (very very very beta) version.