Stereo Tool

With small buffer size (1.7 ms)?

yes :]

Sorry to interrupt.

As I had nothing to do I decided to make a modified version of Stereo Tool (BETA 26)

Look at the picture, if you like Hans when I finish I'll upload full, obviously if you agree.

http://img337.imageshack.us/img337/3360/picsw.jpg

As you can see are not finished all the dialogs but this sample may have an idea of how it will look.

@ Dusty
Please go ahead - it looks less messy than my interface, if you upload it people (including myself) can give feedback

I'm not going to make such big changes for the next version yet, I want to get it finished asap now, but I have already some things that I want to fix in the version after that - and I might include a change like this!

When testing with screen maximized and then moving the window Sound Cards Configuration around i get lots of clicks. But when i change buffer size 0,1 ms then it's gone. So making the load more even on the cores might help quite a bit i think.

I think I found what's wrong. Not sure... But now building an update with the following changes:
- Latency 4096 works again
- Priority of thread that sends data from ASIO to processing was still Normal (equal to screen refreshes!), now also set to time critical
- Fixed Bypass mode
- Strange tone (bass boost) at latency 512 MIGHT be fixed... There was at least something wrong there, which I have improved, and I couldn't get it to reproduce anymore.

I'll also add a checkbox (later) to enable using multiple cores even in low latency modes (currently I only use multiple cores in latency 4096 mode, otherwise I didn't want the scheduling to get in the way. But with these high priority settings, and now I send the data to the sound card BEFORE I start processing a block of audio, that shouldn't be an issue anymore).

BETA601-028:
- Fixed latency 4096
- Fixed Bypass mode
- Priority of thread that sends data from ASIO to processing was still Normal (equal to screen refreshes!), now also set to time critical
- Strange tone (bass boost) at latency 512 MIGHT be fixed... There was at least something wrong there, which I have improved, and I couldn't get it to reproduce anymore.
NO CHANGES TO ANYTHING ELSE!

Winamp DSP plugin: http://www.stereotool.com/download/dsp_ ... 01-028.exe
Stand alone version: http://www.stereotool.com/download/ster ... 01-028.exe
VST version: http://www.stereotool.com/download/vst_ ... 01-028.dll
VST version (No SSE2): http://www.stereotool.com/download/vst_ ... 01-028.dll
Command line version: http://www.stereotool.com/download/ster ... 01-028.exe
Linux command line version: http://www.stereotool.com/download/ster ... ETA601-028 [not available]
Linux GUI version: http://www.stereotool.com/download/ster ... ETA601-028 [not available]


What remains for 6.01:
- Multiband: Adjust band 3 (and others?) 'soft limit' behavior at very low latencies. Maybe: Also check clipping (also for band 3, might be re-enabled!). DONE! - 1 hour
- Multiband: Adjust extreme EQ settings before processing to avoid issues caused by steepness. - 1 hour
- Multiband: Add 'Enable' button for steepness. 1 hour
- Performance: Multiband steepness: Moving UP can be done inside current loop, no separate loop needed. Maybe down too. Currently Multiband is FAR more expensive than before. - DONE, solved in a different way. - 1 day
- MAYBE: Make Steepness smarter. That would much better preserve the audio, especially at very low latencies! How: Instead of setting all the levels at AT MOST the level of neighboring bands + a bit, combine adjacent bands, determine total output level, and then fix it such that this combined output level is approached more. (So one very low, one very high --> one a bit less low, one a bit less high instead of both low).
- Fix NOISE GATE behavior in VST plugin
- Fix 'red output bar' issue. DONE - 1 day?
- Fix Highpass filter for higher input frequencies.
- Dynamic audio processing window: I've tested this at latency 512, and there it helps. But I don't have a clue what the effect is on higher latencies. They might also sound better, but they could just as well sound worse. - 2 hours. Result: 512 and 1024 got better, 2048 and 4096 got worse. So only turned on for the first two.
- Dynamic audio processing window: CPU load is probably a lot higher (haven't measured it yet) due to the dynamic adjustment of the behavior. The dynamic code was originally intended to be executed only once when a latency was selected, and it's not optimized at all. Fixed, CPU load reduced, and for latency 2048 and 4096 there's no difference. - Optimize, 1 day
- Reduce downsampling frequency because currently very high frequencies (21-22 kHz @ 176.4 kHz input sampling rate) in the input can cause spikes even if Hard Limit is used. DONE - 1 hour
- Vibrations caused by Very deep bass distortion protection at latency 1024. Also (but far less noticeable) in higher latency modes. No issue at latency 512 because there it's turned off. - Fixed, turned it on for latency 512, and turned other bass filter OFF for 512 because it caused distortion.
- Check difference in behavior between 44.1 and 48 kHz input for multiband! This could potentially result in really big differences. - No
- Performance: Multiband: Remove sqrt(sqrt(cos())), pow(x, .75) etc. - too expensive, replace by lookup table. - NOT FOR NOW, would increase memory usage and hence risk more page faults, so it's not sure that this would improve the performance. - 2 hours
- Performance: Move chain variables to a single Struct DONE - 1 hour
- Latency: Attempt to reduce Composite Limiter sampling latency - there is no audio anywhere near the filter frequency, so a much shorter delay might still work very well - DONE, composite limiter latency is now 0.9 ms at latencies 512 and 1024 (~1.7-2 ms at higher latencies)! It can be reduced a step further (to 0.5 ms) if I allow a bit more distortion - don't know if that's useful.
- Chris: "I still hear diff on Bass and kick between Beta 16 vs Beta 08 on 2048 latency. I hear more bass and kick on Beta 08. Pls check!" - No longer true, apparently fixed in BETA020... (Which does not make sense at all, but anyway)
- And I need to check how much the performance is impacted by the latency improvements, in the case where no upsampling and downsampling is needed. This seems to be impacted way more than I expected (could also be Multiband steepness --> Not anymore, fixed). Ah, got part of it: 1% is steepness. Which leaves about 3% to be explained. Het is NIET de FM Hard Limit - ook al bereken ik daar nu meer van. Wellicht chain2 calls? - No, wrong again. Decreased Steepness grain match from every 4 to every 16 samples, extra CPU load is now only 2% - acceptable.
- Check/fix Bass Boost ringing reported by Bojcha for higher 'upto' frequencies. REDUCED it a bit, hope that suffices... Less steep filtering (ie. bigger difference between first 2 frequencies) helps.
- Attempt to set GAUSS back to 0 - gives MUCH better processing of most filters (no high frequency noise). BUT: Loudness effect in Bjork - It's Oh So Quiet - can that be resolved in another way? BUSY, 1 day?
- Frequencies between 60 and 75 Hz are not handled properly yet, and can still cause vibration effects at soft high frequencies in latency 512 mode. (But FAR less than in version 6.00). Fixing this will probably increase artifacts for bass in this frequency range.
- Bojcha: "There is strange "tone" at LEFT channel (tested ST dsp), caused by Bass Boost, but not always!" Seems gone now (601-BETA028)
- ASIO latency: Add configurable ASIO granularity
- ASIO latency: Add active output push instead of reactive. - No longer needed - I think. Data is now sent to output BEFORE processing. And there's always some processing delay. Might become more interesting when CPU load goes down.
- ASIO latency: Make option to increase ST priority. BUSY
- Fix BYPASS mode in stand alone version DONE (601-BETA028)
- Fix 4096 in stand alone version - DONE (601-BETA028)
- Change ASIO latency interface (lower values, more fine-grained; display actual latency after rounding)
- Check ASIO on single core behavior...


Questions:
* Multiband: Question: Is Steepness behavior ok?
* Loudness: QUESTION: The changed Punch behavior, is that good or bad? Should I attempt to let Punch behave as it did in the past as much as possible, or not?

At latency 512, Steepness can now be set a bit higher than before because there are far less artifacts.


For 6.02:
- It's possible to send data to an audio buffer AFTER I've returned control to the driver if I call ASIOOutputReady() when I'm ready
- Add non-phase linear Multiband stage between AGC and incoming_copy_needed.

You got, appropriately, distracted by the ASIO issues yesterday, but I'm still wondering about the effective dB/Octave slope of the highpass filter. As I said, the lowpass is significantly steeper and more effective, with levels being anywhere between 20 dB and 30 dB lower for the lowpass than the highpass...

You keep talking about lingering bass boost artifiacts, ringing, and etc, etc, etc... Could you take a look at this as a potential source? It might be absolutely normal, but what I can see happening is some of the signal there still being loud enough to get boosted.

Brian: This is not the cause of those artifacts. Because these artifacts only occur at very low latencies, and the non-phase linear highpass filter is the same for all latencies.

I just check the highpass filter, and it's equally effective as the lowpass filter (audio drops to around -140 dB), BUT: The lowpass filter is repeated at the end of all the processing, the highpass filter is not. So anything in between (including Multiband) can cause lower frequencies to appear. And that happens especially at lower latency settings, because there it's more difficult to separate frequency bands.

I'm only getting -90ish on the highpass side... I can see the drop to -120 or lower for the lowpass, hence the difference I'm talking about, but whatever...

Further: -90ish only happens if I put the highpass at 150 Hz. For the usual frequency I've been setting at, 35 Hz, at most I get only 15-20 dB of reduction, -60 to -70 is typical, but there are sometimes spikes from 0 to 20 Hz that make it up as high as -40. If I was really seeing -120 or -140, do you think I'd be saying anything?

-Brian, Frustrated and going off to my corner