I wanted to know whether line-out has the same power as headphone port, so I can use the two interchangably.

No the Line out is lower powered than the headphone. The Line-out is "Clean" without crap that occurs as a result of using the internal amp in the portable player. you will use this clean line-out signal to connect to an external headphone/speaker amplifier for best results.

I recommend you build that little Mint CMOY amplifier to begin with. It will teach you a bit about these amps and headphones and impedence matching...

I did not know that the headphone port passes through an internal amp. Is that always true? Most of the devices I use, such as PC sound cards, iPod, and various CD Players, uses one port for both line-out and headphones. Does that mean it is amplified or not? Laptops also use one port for both line-out and headphone. Is that amplified?

All sound cards have on board amps. But with the noise and EMF and Ri you can imagine the poor quality they provide.

Some people use line-outs as a misnomer.

yes it is amplified...

So no portables have a true line-out?

No no!!! Portables do!!

You have to find portables that ADVERTISE a separate line out. Like the iRiver IHP-120 / 140 have line outs, so do the Creative Zen's. The apple iPod and the Rio karma have the line out on the "BASE" unit and you can affect the line out sound with the EQ settings so I dont consider them as "Clean Line Outs" but they are there all the same. My SONy D-EJ1000 CD Player has a dedicated Line Out which I use with a Portable Amplifier and my headphones...

So the headphone outs of portables are pure crap...that is a problem, seeing how most notebooks have only one headphone out/line-out. I assume that's amplified and adjusted for headphones?

They are not bad. But you would do better to get a headroom bithead (www.headphone.com - see the products/amplifiers page) to use both as a headphone amplifier and a high quality external sound card. its a trick piece of kit that I am thinking of snapping up. I will get one for review anyway

I was actually thinking of getting an Audigy 2 NX before I looked at headphones. I assume the BitHead is a stereo only device? The Audigy NX can convert any stereo signal into surround. But it lacks some way to convert that surround signal again into 2 channels using a HRTF. Is such an device nonexistent? (well, Dolby Headphones are sort of like that...)

Yeah you could get the Sony/Philips dolby headphones if you like. i think the best option will be to get the normal headphones and an external sound card. The Bithead has two modes of operation which gives it the upper hand. That and the superior sound quality.

HRTF's will be done by software in the games etc. many new games are coming with this since someone (dunno who but some major sound card manufacturer) bought Sensaura inc.

Check this out :-

http://www4.head-fi.org/forums/showt...threadid=59210

I guess you can say the purpose of Dolby Headphone is to simulate a binaural experience. It is not binaural, true, but it is very similar to software that converts stereo/AC-3 into binaural, like Sensaura. I assume they all work by adding spatial cues/reflective sounds to the original tracks, simulating a virtual listening room with headphones. Have you tried Dolby Headphone? I never tried it, but based on working principle I'd say they are the same as the software you use to convert audio to binaural. Though it is probably not as good since you don't get to use ur own HRTFs.

You cannot recreate your own HRTF's unless you create a 100% accurate model of your own head and ear canals. We can get pretty close with an approximation.

Did you check the Binaural sample I gave you the link to? You have to use headphones when you play that - any headphone will give you awesome results...

I havent tried those dolby cans because I prefer musical headphones. I'll let software do the magic on my headphones with games.

You can make your own hardware for HRTF's which are ultimately delay + attenuation + frequency modulation + crossfeed -> If you can come up with an equation for your head

Alternatively ou can design a system with trim-pots that can be fine tuned to each individuals head - difficult but possible...you got me thinking here...

Can you tell me what software to produce binaural you use? I don't think I have enough experience to experiment with stuff yet. I'll just imitate whatever you use.

I will see if i can FTP the software to you. have you checked the binaural recording that I gave you?? What do you think??