Stereo Tool

Yes but the pilot in Stereo Tool is on... That still maps the high frequencies to the audible range. (It should - but there shouldn't be hiss present at those frequencies).

I turned the ST pilot off. No change. So, I am investigating the sound card's hookup to the outside world.

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Think my level driving the sound card is too low. Also, I am driving ST with a headphone jack output of a fiber optic box, I have to hook an unbalanced audio feed to the sound card's balanced in. I had the "low" side of the input floating. Connecting it to ground lowered the hiss by a great deal. Now, if I can drive the sound card harder...

The input meter on the sound card's software shows audio peaking at -20. To play Devil's Advocate, I would maintain that there should be NO noise at any level.

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True - the Marian cards have a noise level specified at below -120 dB so with those you should be fine.

By the way - if your input level is this low, make sure that you adjust the Input Gain slider in Stereo Tool (under Sound cards -> Input) or the sound will be bad (at least with the built-in presets).

I was able to raise the input to ST quite a bit by getting the sound card up to -2 from -20. In fact, The input was so high the "input" wave form box looked as clipped as the "output" box! Before, I had to use about 15+ dB of preamp gain. Now, at 3.89 dB gain, I'm still filling the input box. Oddly enough, I see no action in the AGC window, just in the gate(?) box below it. I still have to run the pilot about 1.5% lower in Stereo Tool to make it read properly on my modulation monitor. If I set the ST pilot level to agree with the monitor, my modulation tops out at 98%. I want 105%, the legal upper limit. The only way I see to get there involves balancing the ST pilot injection with the overall level out.

A couple of questions: What is "FM Composite Limiter Overdrive"? And, although I can't find it now, there was another adjustment related to stronger clipping. What does that do?

THe only feature I've found that I don't care for is the pre-limiter on the cliping page. To my ears it introduces too many artifacts.

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No action in the AGC window? Is that with your own preset or with built-in presets? Because normally there should be activity there, otherwise it could be that almost no processing is occurring.

About pilot level etc: This is probably related to the sound card that you're using. On a Marian Trace Alpha, if you calibrate the level such that with a 1000 Hz tone or with Bessel Null to have 75 kHz modulation, 99% of the measured values when you're actually playing music is at 74 or 75 kHz for loud presets (measured with a Pira analyzer).

"FM Composite Limiter overdrive" - is not used when you use the composite clipper. Before I had a composite limiter. Composite clipper is *much* better.

The 'Simple clipper' is for the free version, you don't need it (and it actually gets automatically bypassed) when you enable the 'Advanced clipper'.

Actually, I have my transmitter hooked directly to an Inovonics modulation monitor. I'm using the M-Audio Audiophile 192, which sounds very nice. As far as modulation, Stereo Tool has absolutely the best modulation control I've ever seen! I set it to peak at 105% and it goes no higher. Stops at 105%. I may try the calibration to a 1khz tone since all that stuff is built into ST.

It seems to me the FM Composite Limiter Overdrive did have an effect, even though I am using the advanced clipper. What do the three bands of the clipper represent?

As far as no AGC action, I'm using a modified B-Town preset and, if the input window is to be believed, hitting it pretty hard. I don't see any way to turn the AGC up without turning up the input some more.

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Phil...if you can, please play the first 7 seconds of the song Black And White by Three Dog Night. When using Breakaway Broadcast Processor with the card you are using, the modulation peaked at 120% or so. I'm very interested in knowing if ST can play that track with that card and still maintain the remarkable peak control you (and I ) are seeing on the Inovonics monitor. Only difference is that I'm using the Marian card. I agree...there's nothing out there (not even an Omnia 9) that has this tight of peak control--uncanny.

As luck would have it, I don't have that song here at work. Every other Three Dog Night song on Gold Discs but not that one. I'll bring it in tomorrow unless there is some hurry-up project that gets in the way.

So the piano notes are a problem? I have no reason to believe they would be a problem here as I've seen absolutely no overshoot here.

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That's great Phil. I tried using that card with Breakaway and there were a few songs that overshot, but that one was the worst. The offending material (from Leif's analysis) is asymetrical bass notes that the compensation on Breakaway was incapable of correcting. He assured me that the Marian Trace Alpha would cure it and indeed it did. If that is a problem peculiar to Breakaway and doesn't happen when Stereo Tool is the processor of choice, that is a game changer.