Memo
Microphone windbubbles measurements
DELTA
Technical-Audiological
Laboratory
Edisonsvej 24
5000 Odense C
Denmark
Tel. +45 72 19 41 00
Fax +45 72 19 41 01
www.delta.dk
VAT No. 12275110
Title
Microphone windbubbles measurements
Number of pages
10
Client
BUBBLEBEE INDUSTRIES
Flæsketorvet 68,1
1711 København V
Denmark
Contact
Poul Mejer
Memo date
7-10-2011
Summary
DELTA has carried out frequency
response and shield effect measurements
on windbubbles´s from Bubbblebee
Industries.
The results show neglible influence on the
microphone frequency response, and a
remarkably positive effect in reduction of
wind noise by 30-35 dB.
See memo for further details.
Gert Ravn
Laboratory Manager
DELTA
Danish Electronic, Light & Acoustics
Technical-Audiological Laboratory - TAL
Windbubbles measurements Page 2 Microphone windbubbles measurements
DELTA - Danish Electronics, Lights and Acoustics is a knowledge centre which among other
topics specializes in electro-acoustic, psychoacoustics and technical audiology relating to human
hearing e.g. test methods, hearing instrument technology and audiometric equipment.
DELTA has carried out measurements on windbubbles from BUBBLEBEE INDUSTRIES.
The measurements comprises of two part´s to characterize the effect:
-
Frequency response measurement in anechoic chamber to discover eventual degrading of
microphone response due to the placement of the windbubbles.
-
Shield effect in wind tunnel to show the efficiency of the windbubbles to suppress wind
noise in the microphone.
Frequency response measurements are carried out at DELTA, Edisonsvej 24, Odense on July
28th 2011. Shield effect measurements are carried out at FORCE Technology, Hjortekærsvej 99,
Kgs. Lyngby on September 6th 2011.
All measurements were carried out using Sanken COS -11 and Sanken CUB01 microphones
Comments – Frequency response
Frequency response measurements show that the effects of attaching the windbubbles on the
microphone are negligible.
Very small influence is seen around the 5 kHz resonance peak of the microphone which is
slightly increased, and followed by a slightly steeper roll-off when compared to the reference
situation without the windbubbles.
The effects are estimated to be very minor and inaudible during use of the microphone with the
windbubbles.
Comments – Shield effect
Shield effect in wind tunnel to show a notable positive effect of the windbubbles. Low frequency
noise in the area 20-200 Hz is reduced up to 35 dB. All measurements are made in direct
turbulent air, as it occurs in nature.
Use of the microphone without windbubbles is estimated to be impossible in wind speed from 5
meters per second and upwards. The shielding effect of the windbubbles reduces low frequency
noise sufficiently to make use of the microphone possible in wind speed´s ranging from 5 to 15
meters per second or even higher dependent of program material.
Windbubbles measurements Page 3 Measurement results made with
BBI-L01 Sanken COS-11 (without metal windscreen) BBI-L02 Sanken COS-11 (with metal windscreen)
BBI-L03 Sanken COS-11 (with metal windscreen) BBI-L04 Sanken COS-11 (with large metal windscreen)
Frequency response
Frequency Response BBI-­L01/-­L02/-­L03/-­L04 50 45 40 35 30 Without 25 BBI-­‐L01 20 BBI-­‐L02 15 BBI-­‐L03 10 BBI-­‐L04 5 0 20 200 2000 Windshield results
Windshield effect for BBI-­L01/-­L02/-­L03/-­L04 25 20 15 BBI-­‐L01 10 BBI-­‐L02 BBI-­‐L03 5 BBI-­‐L04 0 20 200 2000 -­‐5 Windbubbles measurements Page 4 BBI-­L01/-­L02/-­L03/-­L04 at 5 meters per second. 140 120 100 Without 80 BBI-­‐L01 dB SPL BBI-­‐L02 60 BBI-­‐L03 BBI-­‐L04 40 20 0 20 200 2000 Frequency -­ Hz BBI-­L01/-­L02/-­L03/-­L04 at 10 meters per second. 140 120 100 Without 80 BBI-­‐L01 dB SPL BBI-­‐L02 60 BBI-­‐L03 BBI-­‐L04 40 20 0 20 Windbubbles measurements 200 Frequency -­ Hz 2000 Page 5 BBI-­L01/-­L02/-­L03/-­L04 at 15 meters per second. 140 120 100 Without 80 BBI-­‐L01 dB SPL BBI-­‐L02 60 BBI-­‐L03 BBI-­‐L04 40 20 0 20 200 2000 Frequency -­ Hz BBI-­L01/-­L02/-­L03/-­L04 at 20 meters per second. 140 120 100 Without 80 BBI-­‐L01 dB SPL BBI-­‐L02 60 BBI-­‐L03 BBI-­‐L04 40 20 0 20 Windbubbles measurements 200 2000 Frequency -­ Hz Page 6 Measurement results BBI-CUB01
Windshield effect
Windshield effect for BBI-­‐CUB01 50 40 30 dB 20 Shield effect 10 0 20 200 -­‐10 2000 Frequency -­‐ Hz BBI-­CUB01 at 5 meters per second. 140 120 100 80 Without dB SPL 60 BBI-­‐CUB01 40 20 0 20 Windbubbles measurements 200 2000 Frequency -­ Hz Page 7 BBI-­CUB01 at 10 meters per second. 140 120 100 80 dB SPL Without 60 BBI-­‐CUB01 40 20 0 20 200 2000 Frequency -­ Hz BBI CUB01 at 15 meter per second. 140 120 100 80 dB SPL Without 60 BBI-­‐CUB01 40 20 0 20 200 2000 Frequency -­ Hz Windbubbles measurements Page 8 BBI-­CUB01 at 20 meters per second. 140 120 100 80 dB SPL Without 60 BBI-­‐CUB01 40 20 0 20 200 2000 Frequency -­ Hz Windbubbles measurements Page 9