CTS/CTL/CTU/CTZ - Cross-Talk Attenuators Series



  • The Q-Tech range of Cross-Talk attenuators has been designed to provide a low resistance to air flow whilst maintaining a high degree of acoustic attenuation.
  • The CT series should be considered wherever a relief air passage is required to penetrate a building’s acoustic barrier.
  • Four styles are available in both standard and high-performance configurations: -
          - CTS - for simple wall penetration above ceiling
          - CTL - wall to ceiling penetration
          - CTU - ceiling to ceiling penetration
          - CTZ - installation within the wall


  Transmission Loss, dB  
  Octave Band Centre Frequency (Hz) Length
Model .. 125 250 500 1k 2k 4k L, mm
CTS 1 14 18 21 29 30 25 900
CTS 2 20 26 35 40 40 40 1800
Width, W 300 to 1200 in increments of 150mm
Depth, D 200, 300 & 400mm
  Transmission Loss, dB  
  Octave Band Centre Frequency (Hz) Length
Model .. 125 250 500 1k 2k 4k L, mm
CTL 1 15 19 23 31 35 30 900
CTL 2 21 27 36 40 40 40 1800
Width, W 300 to 1200 in increments of 150mm
Depth, D 200, 300 & 400mm
Transmission Loss, dB 
Octave Band Centre Frequency (Hz)     Length 
Model ..  125  250 500 1k  2k  4k  L,mm 
CTU 1  15  20  24  35  38  35  900 
CTU 2  21  28  36  40  40  40  1800 
Width, W 300 to 1200 in increments of 150mm       
Depth, D  200, 300 & 400mm       
  Transmission Loss, dB  
  Octave Band Centre Frequency (Hz)     Length
Model ..  125 250 500 1k 2k 4k L, mm
CTZ 1 15 20 24 35 38 35 900
CTZ 2 21 28 36 40 40 40 1800
Width, W 300 to 1200 in increments of 150mm
Depth, D 200, 300 & 400mm


Table 1 Air Volume, L/sec, W-width, mm
D, mm 300 450 600 750 900 1050 1200
200 90 135 180 225 270 315 360
300 135 200 270 340 400 475 540
400 180 270 360 450 540 630 720
The air flows tabulated are based upon a maximum pressure loss of 15 Pa.


  • Special care should be taken when installing CT Series Cross- Talk units to ensure maximum performance.
  • Consideration must be given to the sound rating of the wall or ceiling being penetrated.
  • It is essential that a tight airseal is achieved between the crosstalk unit and the wall/ceiling penetration.
  • When high performance units are used additional mass lagging of the unit casing may be required to prevent flanking transmission.
  • This can usually be provided by building-in the cross-talk unit during the building construction phase.

Mounting Arrangements

Note:  Airflow shown as a guide only (can travel in either direction)

  Suggested Specifications

  • Room to room Cross-Talk attenuators shall be similar to Q-Tech CT models and shall have the acoustic performance as scheduled.
  • The cross-talk attenuators shall be of a proven design and must have an established history of use.
  • Each unit shall consist of a galvanised sheet metal casing and be provided with internal parallel splitters.
  • The splitter infill material shall be a sound absorbing material as specified by the manufacturer.
  • The infill material shall be covered with a gauze scrim to prevent erosion of the fibres then encased in galvanised perforated sheet metal.
  • The infill material when tested in accordance with AS1530, Part 3, 1989 shall have the following indices: -

          - Ignitability 0
          - Spread of flame 0
          - Heat evolved 0
          - Smoke developed 0

  • The contractor shall ensure that an airtight seal is achieved around all wall penetrations to maintain acoustic integrity.
  • Where necessary additional mass lagging shall be applied to the outside of the attenuators to prevent flanking transmission.
  • All units shall have a constant active acoustic length irrespective of grille or section size.
  • Standard units shall have an active length of 900mm and high-performance units an active length of 1800mm.
  • Acoustic performance specified is quoted as transmission loss as defined in AS1191:1985.

  Auto Cad


Download AUTO CAD file

Download pdf file


The Multiflow TDE 500 to 710 range consist of fully cased, cylindrical models with circular mounting flanges at both ends and a wired terminal box.


The Mini Centrifugal Roof Fan series are the new type roof extract units available in 2 sizes and suitable for vertical and horizontal installation. The low noise external motor and high efficient backward bladed impeller meets the requirement of efficient ventilation in residential, commercial and light industrial applications.

Future 150

The Decor Series can be wall or ceiling mounted and is designed to exhaust stale and moist air from bathrooms, toilets, laundries etc. They are also suitable for ventilating all types of small or closed areas.

TD Silent

The Silent Series is a low profile mixed-flow in-line fan that produces low noise when in operation. It does this through a specifically designed perforated internal skin that directs sound waves produced inside the fan to a layer of sound absorbent material.


The low-profile TD-EVO 250 and 315 in-line mixed-flow fans for circular ducts have a unique design where the support bracket allows the motor and impeller assembly to be fitted or removed without dismantling the adjacent ducting.


AMS started trading late in 1994 with Duncan Burl at its helm, ...


Our Partners

Kruger products are licensed to ...

Our Partners

Company Profile

Air Movement Supplies provides a range, backed by ...



AMS marketing ...



ISO, EC etc ....



CTN, JHB & DBN news ...