New DCS:Ka-50 and FC2.0 sound engine

[Irregular programming]

I have finally found a video recording of the effect I wanted to ask about! What is this effect at 3:10 - 3:20?

I heard it for the first time while watching some waterfall scene in some 80's movie. AFAIK this effect does not occur in real life.

 

 

 

This is most likely a bug, maybe something that your sound card doesn't know how to handle. I've heard it before in other software.

[Nate--IRL--]

I believe the effect is called combing. It is a defect IMHO.

 

In signal processing, a comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. The frequency response of a comb filter consists of a series of regularly spaced spikes, giving the appearance of a comb.

 

http://en.wikipedia.org/wiki/Comb_filter

 

Nate

[sobek]

I believe the effect is called combing. It is a defect IMHO.

 

Yes, this happens when two strongly correlated signals are played out of phase. You can also observe this effect when several bomb explosion samples are triggered in very short succession.

 

There are ways to mitigate this, like if the same file is called repeatedly within just a few milliseconds, you apply an allpass filter with quasi-randomized group delay to the files following the first (of course the group delay needs to differ greatly for each consecutive sound file).

 

I have talked to c0ff about this back in 2012 (IIRC), but it seems he hasn't had the ressources to do it. Edit: Or maybe it's too heavy on CPU cycles, i really can't tell.

Edited April 5, 2014 by sobek

[Bucic]

Ah, thanks, guys!

 

Well, this brings us to another subject - clipping artifacts. A sound gets clipped by subsequent sounds. Evident while firing a salvo of rockets. While I understand ED is short on resources there is a workaround to at least the rocket salvo clipping. It should be achievable to use 3 samples to combine into a full salvo: salvo-start, salvo-middle, salvo-fade. Just like it has been done in Falcon 4.0 for cannon.

 

It raises a question though. Is this a poor Xaudio implementation on ED's part or is this an inherent flaw of Xaudio?

 

@Irregular programming

It's not soundcard-specific.

[sobek]

Bucic, do you have a sample i can listen to?

[Bucic]

Nope, sorry. You'd have to canibalize on a Falcon 4.0 installation :)

[sobek]

Not of the way it should be. Of the way it should not be.

[Lizzard]

If you play Electric Guitar you come across that effect while using Flangers or Phasers..this Effects shift the phases of the Guitar Signals

[Devrim]

This effect goes back 90s. :) I was always hearing that effect in Fighter Bomber game. :P

[Bucic]

Not of the way it should be. Of the way it should not be.

Do you mean rocket salvo sound clipping?

 

EDIT:

That's embarrasing. It seems the issue is long gone

https://www.youtube.com/watch?v=7drjUhI6gzI#t=235

I'd need some external recording of a salvo done in recent DCS version to confirm.

 

Here's an old recording with the issue present

[c0ff]

The wishlist for sound engine is quite long already, but there're other higher priority things right now.

 

Yep, sample randomization (those all-pass filters) and HRTFs are desirable. So are environmental effects (reverbs, delays, reflections, occlusions...).

 

Hopefully, in time.

[Nate--IRL--]

Since we are discussing this.... More Dynamic Range please:)

 

Nate

[Bucic]

The wishlist for sound engine is quite long already, but there're other higher priority things right now.

 

Yep, sample randomization (those all-pass filters) and HRTFs are desirable. So are environmental effects (reverbs, delays, reflections, occlusions...).

 

Hopefully, in time.

Since the sound engine has been rewritten recently could you confirm that Xaudio is not a dead end as far as the main current issues go?

[c0ff]

Since we are discussing this.... More Dynamic Range please:)

Sure.

 

Since the sound engine has been rewritten recently could you confirm that Xaudio is not a dead end as far as the main current issues go?

 

XAudio2 is used just as an audio output API. The engine may very well use ASIO or WASAPI instead, it would make zero difference on the audio quality.

[Bucic]

XAudio2 is used just as an audio output API. The engine may very well use ASIO or WASAPI instead, it would make zero difference on the audio quality.

I know very little of sound engines. What you said is really reassuring. Thank you.