Difference between revisions of "Exakt Information"

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Latest revision as of 13:30, 4 November 2019

Exakt information

On Linn DS/DSM products you can have stereo audio on both Exakt speakers and analogue audio outputs. However, by default, this is disabled and if you have Exakt speakers/ExaktBox connected the audio is muted from the analogue output.
To have both analogue and Exakt audio at the same time, go into Konfig > DEVICE > ADVANCED to enable Dual Analogue/Exakt Stereo Output.
Note: the only difference is that the Exakt audio is delayed by approx 40mS compared to the Analogue output due to the digital processing.

The only other time that the Exakt audio outputs are disabled is when the Internal volume control is turned OFF

Konfig states "EXAKT DISABLED"

If you have the Internal Volume control disabled within Konfig your Exakt-link sockets are disabled. (to stop full volume always playing on your Exakt system!)

Exakt cabling

ALL FOUR pairs of the cables are used in the Exakt-Link cable. This is NOT an ethernet transport cable but an Exakt transport cable. These pairs are used to transmit the audio data, power triggers and a master timing control to ensure that the audio from all channels are in perfect sync.

The Exakt-link has been designed to operate with the CAT-5 cable electrical specifications for signal timings. There have been NO changes to this design for any other CAT cable standards. (updated 2019)

We recommend using the 100Base-T4 / 568B ethernet cable pairing
Exakt Link uses readily available network cables:
  • CAT 5 UTP/FTP
  • CAT 6 UTP/FTP
Note: There is no change in the audio performance of the Exakt Link between Cat 5 or Cat 6 Cables.


Cat-7 and Cat-8 cables may not work well with an Exakt system. For a trouble-free, reliable, high performance installation, we recommend use of Cat 5 or Cat 6.


Typical Ethernet 100Base-T length restrictions guide:

Patch cable < 30M
Solid core cable < 100M


EXAKT-LINK CANNOT be used with:

  • Ethernet Isolators,
  • Ethernet conditioners,
  • HomePlugs/Ethernet-over-Mains devices
  • WLAN bridges etc

Exakt-Link can ONLY be a CAT5/6 cable from Exakt socket to Exakt socket



It is important that the Exakt cables are wired:

  • The cables are paired up using OUT > IN style connections.
  • Any Linn product with these sockets can be linked together. This means you can link a Klimax DS/2 to a Majik ExaktBox-I and have a fully working Exakt system



Exakt-Connections-link.jpg


More information can be found on Exakt systems HERE

What is an Exakt Engine

Exakt technology brings natural sound to the listener.
One Exakt Engine is designed for the signal processing for one loudspeaker. Although when the Linn Surround decoder was launched we added Exakt Engine filters to drive each output full-range and could be assigned their Surround audio channel instead of being a Digital crossover.
The Engine will:

  1. Take the digital stream is then split up to send to the correct speaker drive unit with that loudspeaker.(Bass, mid, tweeter etc).
  2. Each speaker drive unit feed is then adjusted in gain level to match the speaker drive unit performance and any Space Optimisation adjustments
  3. Finally, each speaker drive unit audio delivers a linear phase performance across all the frequencies to ensure they arrive at your ear perfectly synchronised.

The Klimax Exaktbox & Akurate Exaktbox6 have one Exakt Engine with six audio channels.
The Akurate Exaktbox10, Akurate Exaktbox-I and Majik Exaktbox-I have two Exakt Engines. The Akurate Exaktbox10 has 5channels per Engine. The Akurate & Majik Exaktbox-I each have 4channels per Engine.

Exakt Filters

Exakt filters will have different version highlighting any changes. These are primarily the major changes below coupled with minor improvements.
These versions are different between Exakt loudspeaker modules/Exaktbox version etc so will vary between speakers and products.

Exakt filters are the profiles used in the Exakt Engine:

Original Design release

In the original release of Exakt the drive unit models were rather inflexible. The roll-on and roll-off of each drive unit were modeled separately but could only be deployed to correct for both the magnitude and phase of the natural response, or do nothing. At the lowest frequencies there was very little we could do due to the very large processing requirements, so for most speakers we left the natural roll-on alone. Furthermore we didn't have a viable model for the roll-on of ported systems or capability to correct for any fixed internal electronic filtering.

It should be noted that the original release for many supported speakers is not available as a selection using the current version of Konfig. The file format is very different to what is used today and is not readily supported by the Exakt compiler.

Independent highest frequency modelling

For many speakers there is also a version 4 which is not available for selection in Konfig. This was essentially the same as the independent highest frequency modelling filter. Changes were made to all design files to ensure they fell in line with the generic measurements stored in the cloud for the drive units employed by the filter. This was put in place to guard against cloud drop out. It shouldn't ever cause a problem, so version 5 can be considered as a 'belt and braces' replica of version 4.

Independent drive unit modelling

The first and most sizable change to the Exakt filters happened in October 2015 when we introduced Independent drive unit modelling, often described as 'fourth order filters'. This change introduced the current file format used for all Exakt designs and allowed a huge increase in the processing flexibility of the Exakt engine. Each drive unit could now be modeled with a greater flexibility. Improvements included; ported system models (fourth order), support for fixed electronic filters (e.g. subwoofers), independent modelling of magnitude and phase or phase only for low frequencies, better processing by application of new windowing techniques (allowing extension of linear phase to the lowest frequencies).

Extended drive unit modelling

Linn have invested significant effort in improving our acoustic measurement capabilities (bought a very posh laser measurement system, built an anechoic chamber, written a new measurement suite) which gives us a much clearer picture of what the loudspeaker is doing. With Katalyst in the speaker we decided it was time to re-examine the 350. The results of this work are described as Extended drive unit modelling. Previously we treated each unit in general terms, correcting for the roll-on and roll-off behaviour using a model based approach. The extended models treat any consistently measurable acoustic aberrations in the pass band of each drive unit while also adding more precision to the fit of the general models. The result is a response from the speaker which runs more closely to linear phase than before. Previous filters resulted in a phase response to within +/- 15 degrees of linear over the full range of the speaker. The extended models get closer still to a truly linear phase response.


Exakt Compiler

The Exakt compiler is the main programme that will take all of the information, Exakt filter, room information... and compile this into an Exakt profile. This is then forwarded to the Exaktbox and/or Exakt speakers.
The different release are to add more products and capabilities to the Compiler.
e.g.

25.0 17 Aug 2018 14:34:58 Added support for Selekt DSM
24.0 12 Mar 2018 10:28:54 Updated for compatibility with new Urika II gain settings
23.0 02 Nov 2017 14:34:26 Save configuartions for Exakt sources to cut down on update time.
22.0 13 Sep 2017 11:48:52 Added support for Exakt sources (UrikaII-phono stage)
.....