ER1/ER2 Sound Delivery Tubes for Small Plastic Eartips

Sound Delivery Tubes (ER1-21) including coupler for ER1 / ER2 tubal insert earphones and small 3mm/4mm plastic eartips. The sound delivery tube is 26.5cm in length and has a constant diameter of 1.35 mm ID × 2.16 mm OD. Two ER1 / ER2 Sound Delivery Tubes Pairs per pack (one red and one blue).

Sound Delivery Tubes are used to connect small plastic tips to the ER1 or ER2 tubal insert earphone. The smooth frequency response of ER-2 earphones depends on maintaining a total of 292 mm (11.5 inches) of the sound channel between the case wall and the eartip outlet. Of this 292 mm total, 22 mm is provided in the eartip, 5.5 mm is provided by the small metal tip, and 264.5 mm is provided by the sound-delivery tubes.

Technical Specifications

• Compatibility: ER1 and ER2 tubal insert earphones
• Tube length (without coupler): 26.5mm
• Inner diameter: 1.35mm
• Outer diameter: 2.16mm
• Packaging: 2 coupler tubes pairs (red and blue) including coupler for ER1 / ER2

Application Note

Caution: Do not cut the sound tube. A change of 10 mm in the length of the sound tube will change the frequency response by 0.5 dB at some frequencies.