Stereo Tool

Hi Bojcha. Can you elaborate on that? How is it hurting audio, and is it all ST SSB modes? What's your experience with Sony car radios? I don't have a Sony car tuner, but had no complaints running SSB. One clear advantage is being able to increase high end audio audio bandwidth running RDS. Are you finding the SSB disadvantages easily outweigh that? After a bit of press/forums coverage from Frank Foti on SSB trials some time ago, it's since been fairy quiet.

Bob, you mentioned some ST SSB modes exhibit a slight drop in loudness that O9 does not. Hans, you would theoreticaly not be expecting a drop in loudness in ST SSB would you? Have you had any other useful field feedback on SSB?

Cheers AJ

I have some limited SSB experience, mainly with the Omnia 9. When going from SSB to DSB on the 9, I hear no difference whatsoever in a strong signal area. However, there is less noise in a high multipath area and it seems to me that when your station is 1 frequency away from a station running IBOC, the IBOC doesn't take quite as much of a toll on your signal as when running DSB. Overall, it's a good thing from my experience. As far as ST goes, play some white noise through ST and listen on a stereo receiver. Switch from DSB to SSB. There are a few different flavors of SSB on ST. Try them all. At least one of them will penalize your loudness (especially at higher frequencies) by 1-2db. There's at least 1 that has no loudness penalty. I don't recall which is which at the moment, but I suggest avoiding the one that hurts your loudness. The Omnia 9 offers only 1 SSB mode. In a nutshell, that's my SSB experience. Hope it helps

Well will try to explain you simplest as i can.
First i never belive anyone on word even if it's Frank Fotti.
SSB as a "feature" is mostly invented for car radios since they are more affected by multipath. Our home tuners with fixed antenna, even choosed and tuned by us, is much different thing then car radios, plus car movement. That i guess is already clear.
Also, car tuners ar bit different then home tuners. Usually in blending and point where stereo is lost but stereo "red lamp" is still ON.
So i done test by myself.
I am in area where there a many small hills. I noticed that both of our stations have exact "points" where multipath occures. So i tested around 20 points where that happens.
What happens on every of those places is that any SSB mode do almost nothing! (switching SSB and DSB). By "hurting audio" i mean that i really hear loss of highs and they also sounds different and stereo is lost but not same loss on every track.
I really wanted to find example where it is do something. I prepared camera to record all, but there was nothing to record. It simply do almost nothing.
It's true that will give you room to set LPF to even 18kHz, and for that i would choose "Steep Optimal"
However in Omnia.9 default LPF was 17.5kHz with SSB.. but now it's bit less.
Me, i would never go more then 16.5.

I guess the latest multipath cure is using the stokkemaster mode,which is entirely new to me.The SSB did nothing here.I'd be interested in hearing more views on using the stoker mode.I thought it was just used in the Netherlands.

Correct, it is mandatory in Netherlands

See also this thread. viewtopic.php?f=3&t=4972

I hadn't expected that the Stokkemask filter would help this much (and I still don't really understand why it would) - but apparently it does

Thanks Guys.

Bob, I tried both pink and white source noise > ST > MPXTool (Stereo & Mono modes) > CBS/ITU Loudness meter. No measurable difference (<0.1db ITU) between DSB mode and any of ST's SSB modes. Perhaps it is the way a particular receiver you tried behaves with the different SSB modes - Bojcha reported SSB issues with some Sony car tuners.

Interesting! My receiver was an Inovonics 530 FM Modulation Monitor. And I just tried it on the McIntosh MR78 tuner (both of these are top tier receivers by any reasonable assessment) and using the Extreme SSB setting, both receivers on VU Meters showed about 1 db of loss--interestingly enough, the loss is there on mono reception as well. Tried this with and without de-emphasis on the monitor. Is there a way of attaching an audio file? If so, I can demo the difference in white noise as I switch from SSB to DSB. My White Noise source is Adobe Audition fed to an LPB stereo console which feeds the analog inputs of the Marian Trace Alpha sound card. I don't recall the circumstances now but it seems that I generated a signal internally in ST and the loss didn't happen, but with regular program input, it did. But I can't find a way of generating white noise internally with ST so I'm second guessing myself on what I did at the time. Is your White Noise feeding the analog inputs of the sound card?

I'm working on an improvement of the Stokkemask filter to have less effect on the audio. So far it seems to work well but the CPU load is going up a lot (TOTAL cpu load is 26% higher now). Tests will be needed to determine whether the new filter works for multipath as well as the current one (I expect that it will), but first I'll try to reduce the CPU load...

(What is different is that I - among others - switched off a smoothing step, which might cause brief RF spikes to be filtered out less well. The Stokkemask specification allows this (my filter is in some ways a lot stricter than the specification), and in my analysis view (which doesn't perform this smoothing) I see that there are more overshoots - but they are small. To be really sure that things are compliant I'll need to attach an analyzer to it - but even if it's not compliant for people outside the Netherlands it should work file.)

Thanks Hans - look forward to trying that if I can - possible downside of running 2 ST instances with all options on the one pc I think that infamous US driving demo Youtube clip of DSB vs SSB did not help SSB hopes and expectations. I'm inclined to agree with Bojcha in so far as I haven't found situations with any noticeable SSB improvement in multipath areas.

Bob, Thankfully we don't have IBOC here... To answer your query, it was all digital path within pc. My pink/white source files were from here; http://www.wavtones.com/functiongenerator.php Played in Winamp on loop repeat, selecting Breakaway pipeline as output (demo version will do - but I think there is a freeware virtual cable around too that was mentioned on this forum) and selecting Breakaway pipeline as ST input. Then ST output via Breakaway pipeline#2 to MPXTool input (demo version with 60s live input restriction fine for this). MPXTool Output to ITU loudness meter.

I also have an Inovonics 530. Have not tried it with SSB. Good unit for its time with great metering, but not convinced it is the most accurate unit for fine resolution measurements on program with modern ST type composite clipping etc. To set up a tx for that extra few percent modulation, I don't use it. Tone vs program, it seems to overshoot/read just a bit high on program.