you fool windows you can't get fooled again

October 16, 2005 2:34 PM

Windows XP: What does the "Speaker setup" option do, if you choose one of the various stereo options (desktop, laptop, monitor stand, monitor side, keyboard, headphones)? How does it change the waveform? It seems to me that things sound better if I pretend my headphones are desktop speakers...

Also, is it possible for Windows to tell when I have headphones attached, or are we meant to change this option every time we plug them in?

posted by thirteenkiller to Computers & Internet (3 answers total)

Best answer: What options you have and how well they work will depend on what type of audio chipset your computer has. If it's any good at all, it's using some kind of psychoacoustic mojo (most likely a head-related transfer function, HRTF, or an approximation thereof) to correct for the type of speakers you have and their typical positions. Lesser chipsets may simply boost or synthesize frequencies that speakers of various sizes typically have trouble producing. Your ears are of course the final judge of what sounds best to you -- if your headphones sound best with the speaker type set to "desktop speakers," then go for it.

I've not seen any chipset that can tell when you have headphones plugged in. This might technically be possible because headphones have higher impedance than speakers. But then, most computer speakers have amps, and these are impedance-matched to headphones since they know they're going to be plugged into headphone jacks, which throws that out the window.
posted by kindall at 5:57 PM on October 16, 2005

Sound Blaster Live!'s with the IR Drive in the front send a notification to the sound card driver when the headphones are plugged in -- although that has separate configurations for the headphones anyway.
posted by spiderskull at 7:22 PM on October 16, 2005

I would venture a guess that the only thing that this really matters for is gaming that uses the DirectSound API to do 3d positional audio. I can't really see it making a lick of difference for just normal stereo sources. I suppose it could matter whether you selected 2 speakers or 4 speakers when it comes time to watch a DVD with ac3 5.1 sound, but I can't imagine ac3filter downsampling to stereo despite there being 4 audio channels available just because you set the preference to headphones or 2 speakers.

Now, that's just from the windows standpoint. The soundcard's drivers can also come into play. I have a Creative sound card and it has an option somewhere in the settings to "Enhance spatial stereo when using headphones." I'm not sure exactly what it does but I suspect it just causes there to be slighly more channel seperation so that things sound more "spacious" or "richer" or whatever when using headphones.

About sensing when you've plugged in headphones, I would guess that in general it's not possible. It would only be possible if the jack had a continuity switch such that the card can tell when something is plugged in. Most soundcard jacks don't have this, but a few do - the SB Live! LiveDrive is one.
posted by Rhomboid at 8:13 PM on October 16, 2005