Graham's Line Identification Tone System ( GLITS ) is a test signal for stereo systems devised by BBC TV Sound Supervisor and Fellow of the IPS Graham Haines in the mid-1980s. It comprises a 1 kHz tone at 0 dBu (-18 dBFS ) on both channels, with interruptions which identify the channels.
9-492: The left channel is interrupted once for 250 ms every 4 seconds. 250 ms later the right channel has two interruptions of 250 ms spaced by 250 ms. This arrangement has an advantage over the EBU stereo ident tone in that each channel is explicitly identified as belonging to a stereo pair. The EBU Technical Document Multichannel Audio Line-up Tone (Tech 3304) defines stereo lineup tone as having an interruption in
18-472: Is a 2 kHz tone at -24dBFS on all six channels – the lower source signal level ensuring that any derived downmixes remain close to -18dBFS. The alternative EBU multichannel ident tone follows a format more closely associated with the film industry. A sustained 80 Hz runs on the LFE channel throughout the sequence. After a 3-second period of constant 1 kHz, -18dBFS tone on all main channels, each channel
27-582: Is continuous on the right. This pattern of interrupts has been chosen to prevent confusion with either the EBU stereo ident or BBC GLITS tone after stereo mix down. The last section consists of 2 kHz tone at -24dBFS on all six channels. This can be used to check phase between any of the 5.1 legs. When the tone is summed to stereo using default down-mix values this section should produce tones of approximately -18 dBfs on each channel. The BLITS sequence repeats approximately every 14 seconds. EBU Tech.3304 – BLITS Ident This broadcasting -related article
36-423: Is identified in turn with a 0.5s pulse of 1 kHz tone, separated from its neighbours by 0.5s silence. The ident sequence starts at Front Left and continues clockwise through each available channel. The amount of time between the 3 second constant tone periods indicates the total number of channels in the system—e.g. a 7.1 system will have an ident sequence lasting 8 seconds. Snell & Wilcox have used
45-418: Is made up from short tones at -18 dBfs to identify each channel individually: Ø L/R: Front LEFT and Front RIGHT – 880 Hz Ø C: CENTRE – 1320 Hz Ø Lfe: (Low Frequency Effects) – 82.5 Hz Ø Ls/Rs: Surround LEFT and Surround RIGHT – 660 Hz. The second section identifies front left and right channels (L/R) only: 1 kHz tone at -18 dBfs is interrupted four times on the left channel and
54-450: The AES channel format order (L, R, C, LFE, Ls, Rs), followed by an EBU-style ident on just the front left and right channels, again at -18dBFS and with four interruptions on the left channel. The four interruptions provides a unique confirmation that the stereo or mono downmix came from a 5.1 source and avoids any possible confusion with stereo EBU or GLITS downmixes. The final BLITS tone sequence
63-477: The BBC and other European and US broadcasters to identify and lineup 5.1 broadcast circuits. It is also an EBU standard: EBU Tech 3304 . It is designed to function as a 5.1 identification and phase-checking signal and to be meaningful in stereo when an automated downmix to stereo is employed. BLITS is a set of tones designed for television 5.1 sound line-up. It consists of three distinct sections. The first section
72-466: The following on the embedded audio in their VALID8 (Video Audio Line-up & IDentification) equipment: Black %26 Lane%27s Ident Tones for Surround Black & Lane's Ident Tones for Surround ( BLITS ) is a way of keeping track of channels in a mixed surround-sound , stereo , and mono world. It was developed by Martin Black and Keith Lane of Sky TV London in 2004. BLITS is used by Sky,
81-452: The left channel only, lasting 250 ms every 3 s. There is now an official EBU standard for a multichannel BLITS 5.1 channel ident tone which is also described in the Tech 3304 paper, along with an alternative film-style multichannel ident tone system for systems larger than 5.1 arrays. Blits plays a sequence of tones (based on the musical notes A and E) at -18dBFS on each channel in
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