HP RM500SL manual Recd real-ear to coupler difference, FastFacts 15.2 Recd facts

15RECD (real-ear to coupler difference)

15.1Section overview

The RECD measurement procedure may be accessed by selecting RECD from the REM tests list or from the Audiometry poster within Speechmap. An optional RECD transducer is required for RECD measurements.

This section covers the following topics:

15.2: RECD facts

15.3: RECD coupler response

15.4: RECD real-ear response

15.5: RECD results

FastFacts 15.1: RECD (real-ear to coupler difference)

15.2 RECD facts

Individual RECD values are derived by comparing the real-ear SPL for a given test signal to the 2cc coupler SPL for the same test signal. These RECD values are used to: (1) convert HL threshold and UCL obtained using insert phones to SPL values, (2) simulate real-ear measurements from 2cc coupler measures (S-REM); and (3) derive 2cc coupler targets from real-ear aided targets.

If you use insert ear phones for audiometry OR if you verify using S-REM, you should measure RECD (preferred) or use age-related average RECD.

If you use headphones or sound field for audiometry AND you use REM for verification, RECD is not applied in any way and need not be measured.

If you use 2cc coupler targets, you should use measured or age-related RECD.

Insert phone audiometry with measured RECD and REM verification provides the best fitting accuracy, with S-REM verification being slightly less accurate. Insert phone HL data with age-related average RECD is next best.

This software provides average RECDs for 1 - 60 months, 6 - 10 years of age and Adult. A sampling of age-related foam-tip HA-2 RECD values is shown below.

Age/Freq	250	500	750	1000	1500	2000	3000	4000	6000
1 month	3	8	9	12	15	15	16	20	23
12 months	3	6	8	10	10	11	11	15	17
24 months	3	5	7	9	9	10	10	14	15
36 months	3	5	7	9	8	9	9	13	14
60 months	3	5	7	9	7	8	8	13	13
8 yrs - Adult	3	4	6	8	7	7	8	13	13

Values are from DSL 5.0 but differ from DSL in that values for 119 months have been used for ages >119 months. DSL 5.0 RECDs differ from DSL 4.1 RECDs.

FastFacts 15.2: RECD facts

0611 RM500SL User’s Guide Version 2.8 Page 60