Loudspeaker Test. Report

Transcription

1 ACOUSTIC & ELECTRO-ACOUSTIC CONSULTANTS Rayleigh House Partners: 21 Queen Anne s Place, Bush Hill Park P.W. Barnett MIOA, MASA, F.Inst., SCE, MAES North London EN1 2QB J.L. Goddard (administration) Tel: Fax: Associates: amsac@btinternet.com H.M. Goddard MIOA, M.Inst., SCE, MAES Web-site: P.N. Huffer B.Sc., MIOA Loudspeaker Test Report Manufacturer: Penton (UK) Ltd. Type: Music Cabinet Model: JD2T For: Penton UK Report No.: 1278/LS/JD2T Prepared By: P. Edwards B.Sc. February 22 AMS Acoustics, London, February 22 Electro-Acoustics: Environmental Acoustics: Speech Intelligibility: Architectural & Building Services Sound System Design Noise Nuisance Prediction Models Acoustics: Conference Systems Traffic Survey RASTI Measurements Building Services Noise Reverberation Enhancement HSE Hearing Risk Word Score Measurements Room Acoustics Emergency Evacuation System Design Expert Witness Reverberation Control Loudspeaker & Microphone Testing Noise Control Offices in: Hong Kong and USA VAT No

2 R.1278/LS/JD2T 1. Object 1.1. The object of this Report is to present measurements of the acoustic performance of the JD2T device. 2. Scope 2.1. The following characteristics were measured On-axis frequency response Polar response Impedance Applied voltage On-axis 3 rd octave band sound pressure level from which the following are calculated a) Directivity Index (db), tabulated and graphical b) Directivity factor, Q c) Effective octave band impedance d) Octave band Sensitivity 1m, 1W/oct) e) Overall Sensitivity: 1m, 1W 1m, 1W 1m, 1W Speech 1m, 1W f) Acoustic Power 1W), tabulated and graphical g) Octave band Power Apportionment (%) h) Impedance bode plot i) Expected maximum Sound pressure level 1m) j) Frequency response chart k) Polar response charts

3 R.1278/LS/JD2T 3. Method 3.1. The device was mounted in Free Space as shown in figure 1 Mounting method E The measurements were made in an anechoic chamber Measurements were made as detailed in AMS Test Method document No. IR/1a/LS/Meth All measurements were made in general accordance with BS 684: Part 5: Results 4.1. The On-axis 3 rd octave frequency response of the device is shown graphically in the appendix The Impedance bode plot of the device is shown graphically in the appendix Polar plots of the device are shown graphically in the appendix Tabulated values of Directivity index, Directivity factor, Sensitivity, Acoustic Power, Power Apportionment, Impedance and Maximum SPL are shown in the Summary data sheet given in the appendix The Directivity Index has been calculated using Gerzon equal angle, weighted area method. 5. Notes 5.1. Sensitivity The octave band sensitivity is produced in its useful form for calculations. It should be noted that the octave band sensitivity is given as 1m, 1W/Oct. To determine the output when only the overall power is known, then only the overall dba or dblin values should be used. For more detailed information refer to AMS Acoustics Data Sheet Loudspeaker Sensitivity Interpretation of Results Polar Plots For convenience each polar plot has been normalized to db. For this reason caution is advised when comparison of levels between octave bands is made. The reference axis frequency response should be used for comparison purposes.

4 R.1278/LS/JD2T 6. Engineers Notes Reference point located at geometric centre of enclosure. Reference axis perpendicular to face of drivers and includes the reference point.

5 R.1278/LS/JD2T Loudspeaker Information Manufacturer : Penton (UK) Ltd. Model Code : JD2T Type : Music Cabinet Colour : Black Serial No. : None Batch No. : None Other Markings : NM Backbox : As Supplied Grille : As Supplied Weight (grammes) : 155 Depth (mm) : 13 mm Width (mm) : 13 mm Height (mm) : 22 mm Special Features : Rotary tapping selector Internal Details Driver Types/Sizes : 4" Cone Driver, 3/4" Dome Tweeter Driver Serial No.(s) : NM Driver Markings : NM Damping Material : NM Available Tappings : 2W, 1W, 5W, 2.5W, 1.25W (1V) Electrical Details Resonant Frequency(s) : See Impedance Plot Cross-Over Frequency(s) : NM Nominal Impedance 8 (ohms): Inductance : NM Capacitance : NM NM = Not Measured, NA = Not Applicable Originator: Countersigned:

6 R.1278/LS/JD2T Manufacturer : Penton (UK) Ltd. Model Code : JD2T Mounting : Full-Space, Free Field Transformer Tapping : 2W Reference Axis Located at : degrees Frequency (Hz) Parameter k 2k 4k 8k db dba Axial Q Directivity Index (db on Axis) Sensitivity 1m, 1W/Oct) m, 1Wt)25Hz-4kHz m, 1W)Speech Shape Acoustic Power 1W) Apportioned Power (%) Effective Impedance (Ohms) Expected maximum SPL 1m) Test Signal: Pink Noise(1Hz-1kHz) Directivity Index db k 2k 4k 8k Frequency, Hz Acoustic Pow er 1W k 2k 4k 8k Frequency, Hz

7 R.1278/LS/JD2T JD2T Band Limited Frequency Response (Norm alised to db) 5-5 Relative Level, db IEC 3rd-Octave Frequency, Hz Impedance Bode Plot Impedance, ohms Frequency, Hz Phase Angle, degs

8 R.1278/LS/JD2T JD2T Left & Bottom Hz Right & 4 Top Hz Horizontal Vertical Hz kHz kHz kHz kHz A-Weight

9 R.1278/LS/JD2T JD2T Wide Band Frequency Response (Valid from 63Hz to 2kHz) Note: The wide band frequency response is derived using MLS methods and does not necessarily relate to the sensitivity values given in the summary table.

10 R.1278/LS/JD2T Loudspeaker Mounting Methods Backbox Driver & Grille Mounting Method A Loudspeaker Mounted in a Reflective Baffle Mounting Method B Loudspeaker Mounted in an Absorbent Baffle Mounting Method C Loudspeaker Mounted on a Reflective Baffle Mounting Method B Loudspeaker Mounted on an Absorbent Mounting Method E Loudspeaker not Attached to any Surface and Radiation Unaffected by nearby Reflecting Surfaces