Rapture3D Gaming - Stereo Hints & Tips

If you're using the Rapture3D game engine in Stereo, there are quite a few things going on, some of which can be a bit confusing. Sorry. Hopefully this page will make some things a bit clearer!

Surely stereo is just stereo? Why can't I just get started with my game and have everything Just Work? Well, you can. The Rapture3D "User" and "Game" editions select some solid, sensible default settings for you based on what it can find out from Windows. However, it doesn't know everything about how you're listening, so it can't select more exotic techniques safely, which is where some of the really fun stuff is! It's worth spending a few minutes getting to know what Rapture3D can actually do.

If you're using 5.1 or 7.1 systems or beyond you'll probably get better results setting Windows and Rapture3D up to use all of those speakers. This page is focussed on getting the best out of Stereo (i.e. two channel) operation with Rapture3D.

These notes apply broadly to the "Advanced" edition too, though the way that outputs are wired up is a bit different, and configuration is more flexible (complicated).

Surely Stereo Is Just Stereo?

Well yes... and no! Stereo has been around for a while, and a much of its development should be credited to Alan Blumlein in the 1930s. Traditionally, stereo is supposed to be played on two speakers, placed symmetrically in front of the listener with an angle of 60 degrees between them. However, that's definitely not the only way we listen to stereo these days. For instance:

  • Speakers are often NOT set up symmetrically at a 60 degree angle. For instance, they may be mounted in a laptop or television at a narrower angle, or shoved on a couple of bookshelves.
  • Often, stereo is played over headphones. It turns out that this is really important, and the best ways to process sound for headphones are quite different to the best ways for speakers.
  • Sometimes "Surround Stereo" is fed to a "surround decoder" which is a piece of A/V kit which can drive more speakers by extracting extra channels "matrixed" into a stereo stream. They don't work nearly as well as "proper" 5.1 or 7.1 systems, but they may improve on classic stereo.

Headphone Stereo

Many people use headphones for gaming, and it turns out that it is possible to produce 3D sound on headphones, but faking the sound colouration and timing that happen because of the way that sound passes around the head (these techniques are generally known as "binaural" or "HRTF" techniques). Rapture3D does some quite clever things here.

What Rapture3D Can Find Out From Windows

On Windows, Rapture3D can find out what speaker layout has been selected in Windows Control Panel. What happens here is different depending on the version of Windows you are using, and the sound kit that is in your computer. Sometimes it's possible to tell Windows that you're using headphones, or stereo speakers, or a surround stereo system. However, sometimes it isn't, and often people just don't change these settings. Not that we'd ever call our customers lazy.

This means that Rapture3D may find out that you want "Stereo", but nothing more about what kind of stereo. So we have to play it safe and give you sound that will sound okay on any of these set ups. In case that seems poor, we should point out that many other systems only provide this option, and it's pretty good - it's just that Rapture3D offers some even better options!

Changing The Stereo Speaker Layout

If you are using headphones, you may be able to tell Windows this in Control Panel. If not, you may be able to tell Windows using the Rapture3D "Layout" program (select "Headphone Stereo" on the first tab). It may be that neither of these will work and Windows or your sound hardware will only let you select Stereo. If this happens, you can select "Headphone Stereo (Compat.)" in Rapture3D. This leaves Windows in Stereo mode, but makes sure that Rapture3D knows you're actually using headphones. We didn't say this was beautiful.

The same applies for surround stereo - there are "Surround Stereo" and "Surround Stereo (Compat.)" options available in Rapture3D.

Selecting A Decoder Method

Telling Rapture3D what kind of Speaker Layout you are using will often improve things. But there's more... On the second "Decoder" tab in the Rapture3D layout program there are different "Decoder Methods" available to refine things further.

Some particularly interesting cases here are:

LayoutDecoder MethodWhat You Should Know
StereoPannerThis is the "one size fits all" option. If sounds are on the left, most of the sound comes out of the left channel and so on. It'll sound okay on just about any stereo speaker layout. Many other audio engines only do this. It doesn't use much CPU.
Headphone StereoHRTF (Amber)This technique is for headphones only and does some seriously scary things to the audio passed through it to take into account how sounds from different directions pass around your head shape. Results vary, but this can often put sounds right out to the sides, behind, and even above and below.
StereoHCTC (Amber)This is another fairly scary option, but this time for use with stereo speakers in front of you. It also takes into account the fact that sounds from the right speaker reach your left ear and vice versa. Be warned that this technique is very sensitive to speaker and head location - if you're not in the sweet spot it may not be better than the Panner technique. It can also be disrupted quite badly if there are acoustically reflective (hard) surfaces to the sides between you and the speakers. But definitely worth a try, as this can provide a surprising sound stage that's quite a bit wider than you might expect.

The "colours" on the HRTF and HCTC options are there because these techniques use assumptions about the frequency response of your head. We normally recommend the "Amber" option, but you may find that a different colour works better for you, because heads are not all the same. Try different colours and find out what suits you best. You can change the Rapture3D settings while a game is actually running from the configuration program (if you can get to it).

Yeah yeah, blah blah - what should I actually use?

Some ideas:

Stereo speakers around 60 degrees, no reflective surfacesWell done! This is a classic Stereo layout and we recommend you use our HCTC decoders, probably "Amber". We'll have selected "Panner" by default though for safety (see above), so you'll need to change the setting yourself.
Other symmetric stereo layouts, including desktop and laptop speakersSelect Stereo and try the HCTC decoders - they may well work. If not, fall back on Panner.
Split-Screen MultiplayerYou might want to give HCTC a try, but you'll probably be better off with Panner.
HeadphonesSelect "Headphone Stereo" or "Headphone Stereo (Compat.)" and find the HRTF Decoder Method that works best for you. "Amber" is normally good. Do not use HCTC. Panner can be used if you're desperate to save some CPU.
Surround decoder in A/V receiverSelect "Surround Stereo" or "Surround Stereo (Compat.)" and select the Decoder Method that matches your kit the most closely. Check your A/V receiver is in the right mode too.
Stereo speakers on the bookcase behind the flower potsOh. Leave "Panner" selected and pretend you never read this page.

Have fun!