G.R.A.S. 45CA User Manual

G.R.A.S. SOUND & VIBRATION
Page 4
Hearing-Protector Test Fixture Type 45CA
Blind Plug
GR1079
Resilient base
Neck
Fig. 1.1 Assembled test xture Type 45CA including Acoustic Plug and Acoustic Cup.
1 Introduction
The G.R.A.S. Hearing-Protector Test Fixture Type 45CA (Fig. 1.1) is for testing
• Hearing protection devices such as ear muffs and earplugs
• Sound sources such as headphones (supra-aural, circum-aural) and earphones.
Thetestxturecanbeusedwithoneofthefollowingmicrophonesorearsimulators:
• 1" or ½" pressure microphones. If used with 1"microphones,thetestcongurationconforms
with ISO 4869-3.
• IEC 60711 (IEC 60318-4) Ear Simulator RA0045.
• IEC 60318 (IEC 60318-1) Ear Simulator RA0039.
1.1 Main Features
The Test Fixture Type 45CA provides for reliable and exact measurements and was designed
withthefollowingfeatures:
• Thetestxture,mountedonaresilientbase(Fig.1.1)thatreducesthenoiseoortoamini-
mum in a typical test situation. Foam plugs and grease (Fig. 1.1) are supplied to avoid sound
leakage along the cable.
• Thetestxturehead,madeforoptimizingtheacousticisolation.
• An acoustic cup and plug for testing the acoustic isolation (Fig. 1.1).
• Arangeofmoulded-rubberKEMARpinnae,e.g.fortestingearplugs,canbetted.
Head
Pedestal (neck + resilient base)
Two 1.5 mm Allen grub screws - must
ALWAYS be tightened when pedestal
and head are assembled
Cup
GR0974
Tube of
Sealing Grease
MI0016
2 x Foam Plug
GR1281

G.R.A.S. 45CA Specifications

General

Brand	G.R.A.S.
Model	45CA
Category	Protection Device
Language	English