E-A-R Auditory Systems FAQ's Do I need to recalibrate my audiometer initially, when an E-A-RTONE 3A or 5A Insert Earphone is connected to my audiometer? Where can I find information regarding specific procedures for calibration of an insert earphone? What is the preferred method for routine clinical bone conduction testing with masking when using an E-A-RTONE Insert Earphone? Do the E-A-RLINK foam couplers contain any Latex or other material that my patients may have sensitivity to? Is the process for clinical masking different with an insert earphone? How much ambient attenuation does an E-A-RTONE Insert Earphone provide? When, and how, should I replace the E-A-RTONE 3A front tubes? Can I replace or interchange E-A-RTONE Insert Earphone cables without concern for calibration issues? Do I need to recalibrate my audiometer initially, when an E-A-RTONE 3A or 5A Insert Earphone is connected to my audiometer? Yes. Any change of earphones requires that an audiometer be re-calibrated. Once an audiometer is calibrated with a specific earphone set it is unlikely that another, even one of the same type, will provide precisely the same sound pressure level at each test frequency without adjustment. Because the operating characteristics of an audiometer can change over time, periodic re-calibration on an annual or more frequent basis is also recommended regardless of the transducer used. Where can I find information regarding specific procedures for calibration of an insert earphone? The E-A-RTONE 3A and 5A Instruction Booklets that accompany each new set include complete pure tone and speech calibration procedures. ANSI S3.6-1996 and ISO 389-2:1994 both provide basic calibration procedures and appropriate RETSPLs for a 2cc coupler connection to a sound level meter/octave band filter. What is the preferred method for routine clinical bone conduction testing with masking when using an E-A-RTONE Insert Earphone? Place the BC oscillator on the preferred site (forehead or mastoid) Find the BC thresholds (unoccluded) at 250 and 500 Hz. Place an insert-masking receiver in the NTE using deep insertion. Remeasure the thresholds at 250 and 500 Hz. Subtract the results of no. 4 from no. 2. This is the OE. Calculate the level of (minimum) effective masking to be applied to the NTE by adding the OE at 250 and 500 Hz to the AC thresholds at those frequencies. (From Dean & Martin, AJA Vol. 9 131-134 Dec. 2000)   Do the E-A-RLINK foam couplers contain any Latex or other material that my patients may have sensitivity to? E-A-RLINK plugs are made from closed-cell polyvinyl chloride (PVC) foam. There is no Latex in the E-A-RLINK plug or stem. The E-A-RTONE 3A Insert Earphone front tubes are a medical grade polyurethane material, and likewise contain no Latex. The foam material used to manufacture E-A-RLINK plugs has been laboratory tested in accordance with modified guidelines of the (U.S.) Federal Hazardous Substances Act (FHSA). Results have been consistently negative for primary skin irritation. In spite of the above, in rare instances, some irritation may occur in certain individuals. In those isolated cases, E-A-RLINK use should be discontinued. Is the process for clinical masking different with an insert earphone? Insert earphones provide greater interaural attenuation (IA) than supra aural earphones, particularly at lower test frequencies, where the potential for crossover is greater. The higher interaural attenuation levels provided in the E-A-RTONE Insert Earphone Instruction Booklet should be substituted for the traditional (TDH) IA values, however, the basic considerations and procedures for clinical masking are the same. How much ambient attenuation does an E-A-RTONE Insert Earphone provide? The overall NRR of an E-A-RTONE Insert Earphone, when used with a deeply inserted E-A-RLINK foam coupler is approximately 25dB. Typical attenuation by frequency is: 125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz 8000Hz   33.3 34.4 34.5 35.0 33.1 39.4 43.7 SD 5.2 4.9 5.0 4.3 4.2 3.4 3.6 When, and how, should I replace the E-A-RTONE 3A front tubes? The polyurethane front tubes on the 3A will over time become less flexible and discolored, just as will a length of hearing aid tubing. Anything that disrupts the integrity of the air seal between the tube nipple and the case nipple will affect the sound pressure at the eardrum. Altering the tube length, or substituting tubing with a length or wall thickness different from factory replacement parts will affect the SPL at the eardrum and the attenuation of the earphone. Replacement tubing should be obtained only from Auditory Systems distributors to insure optimum results. Front tube replacement is generally recommended on an annual schedule, however individual circumstances may warrant more or less frequent replacement. Front tubes fit snugly over the case nipple. To prevent breaking the case nipple when removing the tube it is best to carefully split, with a sharp blade, the portion of the tube that covers the case nipple. It can then be easily removed and discarded. New front tubes have tube nipples on one end to accommodate the E-A-RLINK tips. The opposite end should be widened with a tubing expander to facilitate placement onto the case nipple. A standard hearing aid tubing expander, with its tip filed down to be more slender, works well. The end of the tube should be pushed completely onto the case nipple until it reaches the case surface. As long as no debris or moisture gets into the tubing, no further attention to it should be required until it is necessary for the next replacement. Can I replace or interchange E-A-RTONE Insert Earphone cables without concern for calibration issues? The E-A-RTONE 3A cables contain no electronic components and can be replaced with new cables or switched to another 3A set (even if the impedance of the earphone itself is different) without affecting the frequency response. The 5A cables however, contain electronic components specific to the impedance of the unit, and cannot be interchanged with a 3A unit or a 5A model with a different impedance. 5A cables are both color-coded (gray pod for 10 & black pod for 50 ) and labeled with the respective impedance value.