Headphones

And now for something completely different…

The difference between listening to music using speakers or a headphone is striking.

When listening to speakers:

both ears receive the direct sound from both channels, the sound will mix
for each channel the far ear will receive the sound a fraction of a second later
for each channel each ear will hear the indirect sound as reflected from the walls, floor (bass!) and ceiling.
again the far ear will receive the indirect sound a fraction later

When listening to a headphone, each ear will receive 1 and 1 channel only. No mixing, no delay, no indirect sound.

The latter means that the room acoustics are eliminated.

More details can be found here.

Crossfeed

You can simulate the HRTF by using a crossfeed.
Benjamin B. Bauer was one the pioneers.
A famous article by him: Stereophonic Earphones and Binaural Loudspeakers.
JAES Volume 9 Number 2 pp. 148-151; April 1961.

A crossfeed emulates the HRTF by taking the signal from one channel, EQ and delay it and feed it into the other channel and visa versa.

Your media player might have one or there is a plug-in.

A VST plug-in and a lot more about headphones can be found here: BlogOhl

A VST plug-in simulating both the HRTF and the room acoustics is Isone Pro

Isone pro EUR 20.00

Zero latency processing
Low CPU load
Sample rate support up to 384 kHz
Customisable HRTF's
Customisable listening room and distance
Wide variety of loudspeaker models
Support for 64 bits audio data processing.

The same functionality as Isone Pro but now in hardware plus a little bit more.

HeaDSPeaker 5.1 Headphone Surround System

HeaDSPeaker system consists of two main parts: tracking sensors and a DSP unit.

Tracking sensors should be attached to your existing headphones.

The provided DSP unit processes the multichannel input signal and produces a dynamically auralized stereo signal for the headphones.

HeaDSPeaker is capable of decoding 5.0 multichannel signal from 2.0 stereo sources (the analog output of modern game consoles, for example).

It can also act as a 5.1 or 7.1 USB sound device when connected to a PC or Macintosh computer.

In addition the HeaDSPeaker Home version can decode Dolby Digital and DTS encoded sound from optical S/PDIF.

Connections:

Optical S/PDIF (Dolby Digital 5.1 / DTS 5.1 / 2.0 PCM) [HeaDSPeaker Home]
USB (7.1PCM / 5.1 PCM / 2.0 PCM)
Analog 3.5mm stereo (2 channels stereo / 5 channel DSP-Logic active matrix decoding)
3.5mm stereo plug for binaural multichannel headphone output
3.5mm stereo plug for head-tracker (included) input

Smyth Realiser A8 USD 3,360.00

Includes Headtracking and In ear measurement

Bundled with a Stax SR-202

Sound Performance Lab - Phonitor € 1649,-

Manufacturers description:

In addition to its standard monitoring functions the Phonitor offers new controls such as “Crossfeed“, “Speaker Angle“ and “Center Level“. These are the essential parameters that create the width, balance and overall space within a listening field and how we recognize them coming from the loudspeaker. Crossfeed simulates the frequency dependent interaural level differences from both channels. Speaker Angle determines the stereo width caused by frequency dependent interaural time differences. Center Level regulates the balance between phantom centre and L/R stereo signals.

A review by Sound on Sound

Measurements

HeadRoom has measurements of a lot of headphones.
They explain what these measurements indicate and enables you to compare up to four models on frequency response, distortion, impedance, isolation and square wave response.
This won't tell you how it will sound but gives you a nice indication.