Stereo Tool

Just 2 days after releasing version 7.42 there's already a 7.43 beta

With a number of small but probably very useful changes:

- Normal Output can now be partially separately processed for FM output. So you can generate, for example, a composite clipped 75 us pre-emphasized FM signal and a not or far less pre-emphasized signal for streaming, or a separate FM signal without composite clipping to feed remote transmitters, in the same Stereo Tool instance - no more need to run a separate copy for the stream! Only the clipping and limiting is done separately, so the CPU load does not go up much. Note that the lowpass filter can not be specified separately (lowpass filtering happens much earlier in the sequence and using different values would require doing almost all the processing twice).
- AM section now contains an 'AM Transmitter' Enabled switch.
- Headroom slider added to the AM section. No more need to abuse the Post Amp slider to create headroom for asymmetrical output. (Note: It's also not possible anymore, so you need to update your settings if you use AM).
- AM pre-emphasis checkbox added in the AM section, so you don't have to abuse the FM pre-emphasis anymore.
- AM pre-emphasis curve (which is slightly different from the FM curve) is now correctly implemented.
- AM signal can now go through the FM sound card output (it's now basically an FM/AM sound card), including tilt correction etc.
If you use the AM settings, you can and should now turn 'FM Transmitter' off!

Windows 32 bit:
Windows stand alone: ----://www.stereotool.com/download/stereo_tool ... 43-001.exe (Build failed, rebuilding now)
Winamp DSP: http://www.stereotool.com/download/dsp_ ... 43-001.exe
Windows VST 32: http://www.stereotool.com/download/vst_ ... 42-001.dll

TODO:
4. Turn AM stuff off if FM is enabled (?) but what about asymmetrical clipping/limiting for FM? -> Extra switch in Expert mode
5. Add pre-emphasize output button for AM pre-emphasis
5. Maybe - if people ask for it - add a C-QUAM mode.

Oops - bug! I just realized that - to be able to quickly check if I'm generating a separate signal - I boosted the level by a factor 10 if I do... So... You can test with this version if the concept works, but the audio is unusabe. I'm leaving this here anyway to get feedback (there are SO many different possible settings which must be handled correctly that I'm afraid of having introduced bugs, although so far I haven't found any). If things are ok, I will remove this in the next build.
Also, I have yet to test that all the outputs are identical to those of version 7.42.

I think everything is ok now and I also fixed a few more things; new build is running.

BETA743-002:

Windows 32 bit:
Windows stand alone: http://www.stereotool.com/download/ster ... 43-002.exe
Winamp DSP: http://www.stereotool.com/download/dsp_ ... 43-002.exe
Windows VST 32: http://www.stereotool.com/download/vst_ ... 42-002.dll

CHANGES:
4. Turn AM stuff off if FM is enabled (?) but what about asymmetrical clipping/limiting for FM? -> Extra switch in Expert mode
5. Add pre-emphasize output button for AM pre-emphasis
Fixed the mentioned and some other bugs in the previous beta. All combinations of settings seem to work now.

OLDER CHANGES:
- Normal Output can now be partially separately processed for FM output. So you can generate, for example, a composite clipped 75 us pre-emphasized FM signal and a not or far less pre-emphasized signal for streaming, or a separate FM signal without composite clipping to feed remote transmitters, in the same Stereo Tool instance - no more need to run a separate copy for the stream! Only the clipping and limiting is done separately, so the CPU load does not go up much. Note that the lowpass filter can not be specified separately (lowpass filtering happens much earlier in the sequence and using different values would require doing almost all the processing twice).
- AM section now contains an 'AM Transmitter' Enabled switch.
- Headroom slider added to the AM section. No more need to abuse the Post Amp slider to create headroom for asymmetrical output. (Note: It's also not possible anymore, so you need to update your settings if you use AM).
- AM pre-emphasis checkbox added in the AM section, so you don't have to abuse the FM pre-emphasis anymore.
- AM pre-emphasis curve (which is slightly different from the FM curve) is now correctly implemented.
- AM signal can now go through the FM sound card output (it's now basically an FM/AM sound card), including tilt correction etc.
If you use the AM settings, you can and should now turn 'FM Transmitter' off!

TODO:
5. Maybe - if people ask for it - add a C-QUAM mode. Probably not too important.

Windows VST 32: http://www.stereotool.com/download/vst_ ... 43-001.dll

Windows VST 32: http://www.stereotool.com/download/vst_ ... 43-002.dll

Your links were a little off, these are the correct ones.

Add it. Be cool to see it.

I'm not at my Stereotool pc at the moment but when using a pipeline input and normal & fm output (192 kHz) , I noticed a strange effect when switching the normal output to bypass. Sounded like it could be a sampling rate thing?

I think I also noticed a small typo - check the AM transmitter window.

Excited to see whats next. It's great to see such awesome development of ST!

Great feature normal output pre-emphasis!
But something is strange sometimes plays like 1 or more samples delay between channels, occurs highs cancelation when switch to mono.
I checked everything including exact mono sound input.

_________________
Urban Junglist

Hans,
I again will say here that there is something wrong with Calibration section . Three options are identical with what they do : Test right silence , Test SSB lower and Test SSB higher. Nevermind what option you check, they causes same display behavour and same result as audio .

Yeah I Would Like You to Add a C-QUAM mode.

_________________
Fidelity over loudness

I listened to the new AM setting and having listened to the pre-emphasized output of some hardware processors, this one sounds quite nice. The harsh ringing sound isn't there. A couple of thoughts :

1) Part 15 stations aren't limited by the NRSC filter that requires a sharp cut at 10khz (probably also true for full power stations in other countries). Would it be possible to have a 10khz NRSC filter switch that would allow licensed US stations to comply with the NRSC standard yet allow Part 15 stations to operate with full bandwidth pre-emphasis?

2) I find it interesting that when I run the low pass filter setting from 16000 (where I run it on FM) down to 10000, I hear a difference. It sounds notably better at 16000. Does it meet the NRSC 10khz standard with the low pass filter set above 10khz? If so, WOW!