Executive summary: free new simple installer for making PC audio sound "out of your head" on headphones, like (ahem) Out of Your Head, Dolby Headphone, DTS HP:X, Smyth Realiser, etc etc. Freeware EqualizerAPO employed for simple setup, actual convolution filters independently researched by Joseph Yeung.
Recently I've come to notice that the free PC app EqualizerAPO has evolved into a powerful beast capable in principle of turning any PC sound card into a full-fledged loudspeaker virtualization system for headphones via its new(ish) channel copying / mixing and convolution capabilities, and all this potentially with zero time lag and very little CPU load. The means to convert this potential into reality, however, has thus far been barred behind either paywalls or esoteric individual research. Having carried out the requisite bookworming and experimentation, together with a light dose of original acoustic research (for creating the actual BRIRs for use with the convolution config), I present to you the borne fruits for free download as follows:
https://www.dropbox.com/s/34tcat3ge7sg5j7/EqualizerAPO%20EFO%20audio%20pak.zip?dl=0
Password: "by Joseph Yeung"
Credits: ARISE, EFOtech, Fanoble Meng, HiByMusic, Mr. D, Kyle "sonophilos" Joyce, Christopher Blomeyer, Jordan "Ephexxis", James Fung (JamesDSP), and anyone I forgot!
Installation instructions:
1. Install EqualizerAPO 32 or 64 bit (according to your system bitness) from the install directory (or obtain latest from https://sourceforge.net/projects/equalizerapo/).
2. Use the Configurator during installation to install APO drivers on your primary sound device.
3. Reboot as prompted by the installer if necessary.
4. Set your primary sound device's Default Format (under Sound->Playback->Properties->Advanced) to 48000Hz and 8 channels if available otherwise 2 channels, and your choice of bit depth. (Devices called "speakers" won't come with a channel config and will simply support whatever audio streams come up, up to the maximum number of channels the device supports.)
5. Copy the files from "7.1 (8 ) channel config" (if 8 channels) or "two channel config" (if 2 channels) to C:\Program Files\EqualizerAPO\config\ . Confirm overwriting the existing config.txt.
6. Enjoy!
Note: Only audio passing through Windows system audio stack (MME, DirectSound, waveOut, etc.) can be processed by the system. That means no WASAPI or ASIO tomfoolery. The sample rate of your sound device (if not your music player app) *must* also be set to 48000 for effects to render.
Additional tweaks:
1. Raise audiodg.exe process priority to raise priority of audio processing to potentially prevent stutters.
2. Use a virtual audio cable program to grant 7.1 channel capabilities to 2 channel audio devices (...but with a bit of latency and very sensitive to CPU loads. Might as well get a 7.1 channel sound card for real. The Terratec Aureon 7.1 seems to be a good cheap solution for USB portable audio)
3. To restore stock sound, simply rename C:\Program Files\EqualizerAPO\config\config.txt temporarily.
EqualizerAPO can be configured using the included "Configuration Editor" program, of which there are the following tweaks for the 7.1 config:
4. The 7.1 audio chain includes a step (3) that reverses the order of the RL RR rear channels to the SL SR side channels, because it seems both channel assignments (FL FR C Sub SL SR RL RR AND FL FR C Sub RL RR SL SR) are in use. The bundled impulse will process for FL FR C Sub SL SR RL RR without the reversal. The
reversal step is enabled by default, making FL FR C Sub RL RR SL SR the default accepted channel assignment.
5. And because so much material out there is 5.1 rather than 7.1, a step (4) is included that evenly distributes SL, SR or RL, RR channel sound (whichever is fed sound, again, this seems to be up in the air) among both S(LR) and R(LR) channels, for a better filled out backstage. Disable this step when listening to real 7.1 content.
Unlike most commercial speaker spatialization solutions out there this setup is tuned to sound at its best even with stereo music material.
Looking forward to everybody's thoughts!