top of page

Recorded "surround sound" is typically delivered through five, six, seven or more speakers. The sounds of the real world come to us from an infinity of locations. We readily sense direction in all axes of three-dimensional space, and yet: the human auditory system is two-channel. One route into that system is headphones.

The weakness of headphones has been their inability to create a spacious and completely accurate sonic image in three dimensions. Some "virtual surround" processors have made incremental progress in this regard. But there is no reason in principle why headphones cannot provide a sonic experience fully as spacious, precisely localised and vivid as that created by multiple speakers in a real room.

Surround | Smyth Realiser

The fact that we can hear direction left and right makes intuitive sense since our ears are on the left and right sides of our heads.  


How do we hear front and back, up and down?  Sounds coming from various directions are altered as they encounter the shape and dimensions of the head and upper torso, and the shape of

the outer ear (pinna).


Our brains are highly sensitive to these modifications but we do not hear them as tonal alterations; rather we experience them, quite accurately, as localisation up, down, front, back, or in between.


This acoustic alteration is called the Head Related Transfer Function or HRTF.

HRTF | Smyth Realiser

Historically, one type of recording has recognised that two audio channels can recreate a three-dimensional experience. Binaural recordings are made with a single pair of closely-spaced microphones and are intended for headphone listening.


Sometimes the microphones are embedded in a dummy head or head/torso to create an HRTF, in which case the sense of three-dimensionality is enhanced.


The reproduced sound space can be convincing, though with no reference to the original environment, its accuracy cannot be attested. In any case, these are specialised recordings rarely seen in the commercial catalogue. Instead, for sound beyond left and right, we have Surround Sound.


Recordings intended to capture sounds both front and rear, and sometimes above, are made with multiple microphones, are stored on multiple channels, and are intended to be played back on multiple speakers arrayed about the listener.


For headphones, the multiple channels of surround sound can be combined, adding the directional signatures that would be imposed on each channel by the positions of the loudspeakers.  Various attempts have been made to "virtualise" the experience of multiple loudspeakers, with varying degrees of success. Surround virtualisers are sold or licensed by a variety of well-known and lesser-known companies. These apply HRTF alterations to the incoming channels, using generalised or average data for pinna, head, and torso shape and dimensions.


Recordings intended to capture sounds both front and rear, and sometimes above, are made with multiple microphones, are stored on multiple channels, and are intended to be played back on multiple speakers arrayed about the listener.

The Realiser provides a completely different experience in which a multichannel (or stereo) recording sounds indistinguishably the same through headphones as it does through a

loudspeaker array in a real room.


The Realiser applies HRTFs to multichannel sound to drive the headphones. But along with other refinements, the Realiser employs three critical components not seen in the other products:  personalisation, head tracking, and the capture of the properties of any real listening space and sound system.

Super charge your library


Personalisation tools to get the most from your PRIR files.

Backup your creations


Online storage of up to 200 PRIR files.


Dramatically expands the capability of the Realiser A16 processor. While the A16 comes pre-installed with virtual movie theatres and studios, new virtual sound rooms can be downloaded and personalised from our Realiser Exchange website.  

  • On-line storage of your own virtual sound room library 

  • Purchase virtual sound rooms of commercial studios and mixing rooms 

  • Exchange (or sell) your own measured sound rooms with other members 

  • On-line DSP tools to personalise and customise virtual sound rooms


Central to the new Realiser Exchange is the members account with sufficient storage to hold 200 PRIR/BRIR files. Members will be able to upload files from their Realiser for backup, for enhancement processing, or for selling on the store, and also download files from this account whether these files be their own, from the library, or purchased.

Exchange/Buy sound rooms


Download PRIRs measured in the best sound rooms. Let other members listen to your room.



Evaluate and rate other PRIRs. Need help or assistance – ask other members.


The home user's first experience with the Realiser is typically the exact emulation of his own speaker system. But any audio system in any room can be measured, stored, and emulated at will. Audiophiles can emulate each others' rooms, speakers, and electronics.


An audio dealer could make an unaffordable system in an acoustically outstanding room available for emulation, or might have arrangements with a studio or cinema for the same purpose.


Or the layout of an existing room can be improved. For example, a center channel virtual speaker can be located behind a solid screen rather than above or below it.


Playback can of course occur anywhere. A home user, for example, can take the sound of his home theater into his bedroom for spectacular sound later at night and without disturbing others in the house.


For professional users, the Realiser affords the ability for a mixing or mastering engineer to replicate a preferred monitoring environment in another location.


The studio can be brought home, or taken on location. A variety of consumer playback systems and rooms can be called up for checking the suitability of a music mix for commercial release. A client can hear a mix in the environment where the engineer created it without travelling there. 


Within an organisation, a proven good monitoring environment can be replicated as many times as there are users who need the room, and the replicated studios can be used simultaneously at any number of workstations, greatly relieving demand on limited facilities and saving the cost of building additional rooms.


Or different monitoring environments suited to different tasks can be accessed from the same physical workstation. 


Today's computer and console games offer brilliantly realistic graphics that immerse the player in the action.


Many games also generate surround sound, but many gamers either use very poor computer speakers, or modest headphones limited to stereo.


With the Realiser, the sound of the game rises to the level of the graphics, hugely enriching the gaming experience.


The Realiser is designed to be simple for basic setup and operation, including the personalisation measurement procedure. However, a large range of adjustments and tools is available for those who want more finely to polish or optimise their setups.

For example, extensive level, EQ, delay, crossover and bass management controls are provided for every channel. A choice of test signals is provided for the best result in various room acoustics.


Measurements can be repeated and combined to lower measurement noise. The angles of the virtual speakers can be fine-adjusted to correct for slight misalignments of the listener's head during measurement; also, a pilot tone system provides audible feedback for precise head alignment just before measurement. And there are many more such facilities, all accessible by straightforward menus.

Smyth Realiser A16
bottom of page