1、 CEA Standard Turntable Measurement Standard CEA-11 S-2014 September 2014 NOTICE Consumer Electronics Association (CEA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilita
2、ting interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards, Bulletins and other technical publications shall not in any respect preclude any member or nonmember
3、 of CEA from manufacturing or selling products not conforming to such Standards, Bulletins or other technical publications, nor shall the existence of such Standards, Bulletins and other technical publications preclude their voluntary use by those other than CEA members, whether the standard is to b
4、e used either domestically or internationally. Standards, Bulletins and other technical publications are adopted by CEA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, CEA does not assume any liability to any patent owner, nor does it assume any obl
5、igation whatever to parties adopting the Standard, Bulletin or other technical publication. This document does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this document to establish appropriate
6、safety and health practices and to determine the applicability of regulatory limitations before its use. This document is copyrighted by the Consumer Electronics Association (CEA) and may not be reproduced, in whole or part, without written permission. Federal copyright law prohibits unauthorized re
7、production of this document by any means. Organizations may obtain permission to reproduce a limited number of copies by entering into a license agreement. Requests to reproduce text, data, charts, figures or other material should be made to CEA. (Formulated under the cognizance of the CEA R3 Audio
8、Systems Committee.) Published by CONSUMER ELECTRONICS ASSOCIATION 2014 Technology however, it is noted that EIAJ is working on a new set of records that they anticipate will be a more advanced series. The records are used mainly to set a level and to obtain a frequency necessary as a reference. This
9、 Committee encourages other Committees to develop measurement Standards for phono cartridges and if the reporting method is consistent with this Standard, the public will have the opportunity of “marrying“ the best cartridge to a particular turntable system. * Consumer Electronics Group CEA-11 iiCON
10、TENTS 1 Scope . 1 1.1 Object . 1 1.2 Standard Test Conditions 1 Ambient Conditions 1 1.3 Supply Voltage 1 1.4 Rated Load Impedance 1 2 Definitions General Terms . 1 3 Definitions Primary Specifications 2 4 Definitions Secondary Specifications . 2 5 Standard Measurements and Reporting Methods 3 5.1 P
11、rimary Specification . 3 5.1.1 Speed . 3 5.1.2 Speed Drift . 4 5.1.3 Wow and Flutter 5 5.1.4 Signal to Rumble Ratio 5 5.1.5 Signal-To-Noise Ratio 9 5.1.6 Lateral Tracking Angle Error . 9 5.1.7 Cartridge Weight Range . 10 5.1.8 Static Vertical Tracking Range 10 5.1.9 Cable Capacitance 10 5.1.10 Effec
12、tive Vertical Mass of Tone Arm. 10 5.2 Secondary Specifications 11 5.2.1 Time for Turntable to Reach Desired Speed 11 5.2.2 Load Effect (Drag) . 12 5.2.3 Pitch Adjustment Range 13 5.2.4 Cycle Time of Multiplay (Record Changer . 14 5.2.5 Mechanical Sensitivity of Tone Arm (see *) . 14 5.2.6 Speed Acc
13、uracy as a Function of Line Voltage . 15 5.2.7 Signal-To-Rumble (Unweighted) . 15 CEA-11 1Turntable Measurement Standard 1 Scope This Standard applies to stereophonic record players for home use. NOTE: 1. The record player shall consist of only the turntable mechanism, tone arm and cartridge. 2. Rec
14、ord changers shall be included in this Standard. 3. The Standard does not cover phonographs which include amplifiers, loudspeakers, etc. 4. For turntable systems without cartridges, measurements shall be made by using a specified cartridge. 5. For turntable mechanism supplied without tone arm, measu
15、rements shall be made by using a specified tone arm and cartridge. 6. Test methods for turntable mechanisms are included in this Standard. 7. This Standard excludes all aspects of safety 1.1 Object This Standard gives recommendations relative to the characteristics to be specified and the methods of
16、 measurement for record players 1.2 Standard Test Conditions Ambient Conditions (a) Temperature 20 2 C (b) Relative Humidity 60 15% (c) Air Pressure 960 100 mba 1.3 Supply Voltage (a) The supply voltage shall be rated voltage (1%) of that specified by the manufacturer, for equipment under test. (b)
17、Frequency shall be rated frequency ( 0.5%) of that specified by the manufacturer and distortion shall be less than 3%. 1.4 Rated Load Impedance The impedance, as specified by the manufacturer, shall be used to terminate each audio output of the record player. Unless otherwise specified by the manufa
18、cturer, the rated load impedance shall be a constant pure resistance. Unless otherwise specified by the manufacturer, load impedance shall be 47 k for velocity sensitive type pickups 2 Definitions General Terms Turntable Mechanism - A mechanism whose function is to rotate a phonograph disc at a pred
19、etermined speed. Tone Arm - A device to support a phono transducer (pickup, cartridge, etc.) and allow its stylus to track a phono record. Phono Pickup (Cartridge) - A transducer designed to convert mechanical modulations into an electrical signal. Turntable System - A turntable mechanism with a ton
20、e arm suitably mounted and fitted with a phono cartridge. Single Play Turntable System - A turntable system designed to accommodate one phono record at a time. CEA-11 2Multiple Play Turntable System - A turntable system that plays one record at a time but can also store additional records to be play
21、ed in succession. Manual Turntable System - A single play turntable system in which the tone arm functions can only be performed by the user. Semi-Automatic Turntable System - A single play turntable system where one or more functions related to the playing of a record, must still be performed manua
22、lly. Automatic Single Play Turntable System - A turntable system that is designed to perform all mechanical functions, relative to playing one record, without manual intervention. Automatic Multiple Play Turntable System - A turntable system that is designed to perform all mechanical functions, rela
23、tive to playing one or more records without manual intervention. 3 Definitions Primary Specifications Speed Accuracy - The difference between the desired speed and the actual speed expressed as a percent of the desired speed. Speed Drift - The deviation in rotational speed of the turntable mechanism
24、 from the nominal desired speed over a specified time period. Wow/Flutter - The cyclical instantaneous variation of the rotational speed of the turntable system. Wow is a slow speed variation and flutter is a more rapid speed variation. Signal-To-Rumble Ratio (Weighted) - The noise caused by mechani
25、cal vibration of the turntable system while. playing an unmodulated record groove, and converted to an electrical signal by the phonograph pickup, referenced to a specified playback level and modified by a specified filter network. Signal-To-Noise Ratio - The maximum unwanted signal induced in the p
26、hono pickup, referenced to a playback level, with the cartridge located in the playing area, but not tracking a groove. Lateral Tracking Angle Error - The maximum angular misalignment of the stylus, over the normal record playing area, divided by the record radius at the maximum error. It is measure
27、d in degrees per centimeter. Cartridge Weight Range - The minimum and maximum weight of cartridges that can be accommodated and still allow setting the minimum and minimum vertical tracking force specified for the turntable. Vertical Tracking Force Range - The minimum and maximum force available, me
28、asured in grams. Tone Arm and Total Cable Capacitance - The open circuit capacitance in picofarads (pF) of one channel from the cartridge terminals to the end of the harness plus any additional cables supplied (including connectors). Effective Vertical Tone Arm Mass - The effective mass of the tone
29、arm/cartridge system at the stylus tip. It relates to the ability of the tone arm/cartridge system to track warped records 4 Definitions Secondary Specifications Time for Turntable System to Reach Desired Speed - The time necessary for the turntable to reach the desired stable speed 3% from a non-ro
30、tation condition. Load Effect (Drag) - The amount of external torque required to reduce the speed of the turntable system by 3%. CEA-11 3Pitch (Speed) Adjustment Range - The range of adjustment of speed from the nominal measured in percent and in pitch. Cycle Time for Multiple Play Record Changer -
31、The time in seconds from the trip point to set down of the stylus measured at the 33-1/3 speed. Vertical/Horizontal Bearing Friction - The force required to overcome the friction of the pivots in the vertical and horizontal planes. Speed Accuracy versus Line Voltage Variation - The affect of line vo
32、ltage variation on speed accuracy. Signal-To-Rumble Ratio (Unweighted) - The measurement of all components of vibration of the turntable system while playing an unmodulated record groove, converted to an electrical signal, but not modified by an electrical filter, relative to a specified playback re
33、ference level. 5 Standard Measurements and Reporting Methods 5.1 Primary Specification 5.1.1 Speed 5.1.1.1 Scope This Standard applies to the measurement of mean deviation from rated speed. 5.1.1.2 Mean Deviation from Rated Speed Mean deviation from rated speed = Measured speed-rated speed x 100% ra
34、ted sp 5.1.1.3 Test Conditions (1) Under rated condition, but with vertical tracking force adjusted to maximum value specified for the tone arm, using a non- modulated groove on a vinyl record. (2) The stylus tip shall be at a distance of approximately 120 mm for 33-1/3 rpm (80 mm for 45 rpm) from t
35、he center of rotation of turntable. (3) Cartridge used for this test shal1 be capable of withstanding the maximum tracking force specified for the tone arm. (4) Pitch control (if available) should be adjusted to provide closest to rated speed at no load condition 5.1.1.4 Method of Measurement (1) Ma
36、ximum Load (Playing Record) A stroboscopic bar pattern that is rotating with a playing record is illuminated by a neon lamp operated at rated power supply frequency. Viewed from above the record, the number of apparent bars passing a fixed point per second (N) is counted clockwise movement being reg
37、arded as positive (+N) counter-clockwise movement as negative (-N). Mean deviation from rated speed = 60 n (2f + N) Rated speed x 100% + Supply Freq. Error Rated Speed CEA-11 4n = number of bars on stroboscope f = power supply frequency of neon lamp Supply Freq. Error = f Rated Frequency x 100% Rate
38、d Frequency f 50 Hz 60 Hz Rated Speed (rev/min) n Speed (N = 0) (rev/min) n Speed (N = 0) (rev/min) 45 133 45.1128 160 45.000033-1/3 180 33.333 216 33.333(2) No Load (Not Playing) Repeat above measurement with test record on platter, but with tone arm/cartridge off record. Report results in paragrap
39、h 6.1.1.5. 5.1.1.5 Presentation of Results Speed Accuracy as a function of load: Rated Speed (33-1/3 rpm) _% No. Load _ % Maximum Load _ (45 rpm) % No. Load _ % Maximum Load 5.1.2 Speed Drift 5.1.2.1 Definition The maximum deviation in rotational speed of the turntable mechanism from the average spe
40、ed over a specified time period 5.1.2.2 Method of Measurement The turntable mechanism shall be conditioned for two (2) hours under standard ambient conditions and then turned off for five (5) minutes. Measurements shall be made according to the method for speed accuracy with maximum load. The follow
41、ing data shall be recorded: Sl= Speed of rotation at 30 seconds (tl) S2= Speed of rotation at 30 minutes (t2) Sa= Maximum speed of rotation between tland t2Sb= Minimum speed of rotation between t1and t25.1.2.3 Presentation of Results Average Speed = Sl+ S2= Sn2 Drift = Sa-Sbx 100 = _ % SnCEA-11 55.1
42、.3 Wow and Flutter 5.1.3.1 Scope This Standard applies to the measurement of wow and flutter in testing record players 5.1.3.2 Definition An undesired form of frequency modulation introduced into the recorded signal by an irregular motion of the turntable system during the reproducing process. The f
43、requency between 0.1 Hz and 10 Hz is referred to as wow, and between 10 Hz -500 Hz is referred to as flutter. If V = average speed, then: Vmax = maximum instantaneous speed Vmin = minimum instantaneous speed Peak wow and flutter = Vmax -Vmin x 100% 2V 5.1.3.3 DIN Weighted Value The value of wow and
44、flutter that is measured by the wow and flutter meter having DIN weighting characteristics 5.1.3.4 Test Conditions (a) Rated Condition: Use the standard test circuit shown in Figure 1. (b) Test Record: Test record for wow and flutter measurement (f = 3150 Hz or 3000 Hz). (EIAJ -CP- 310 -8/51 or equa
45、l). (c) Meter: Specified wow and flutter meter. (As per IEC publication 386) 5.1.3.5 Method of Measurement Under test condition .5.1.3.4, the reproduced signal is measured by the DIN weighted wow/flutter meter. 5.1.3.6 Presentation of Results Wow/Flutter (DIN weighted value) = _ 5.1.4 Signal to Rumb
46、le Ratio 5.1.4.1 Scope This Standard applies to the measurement of signal-to-rumble ratio in testing record players. 5.1.4.2 Definition CEA-11 6The ratio, expressed in decibels (dB), between the output voltage, Uo, derived from the reference signal, and the maximum output voltage, U, derived from lo
47、w frequency vibration within the record player. Signal-to-rumble ratio (dB) = 20logUo U(a) Weighted Rumble Level The rumble level U and Uo are measured through a weighting network shown as Figure 2 in addition to the RIAA playback characteristic. 5.1.4.3 Test Conditions (a) The turntable under test
48、is set on a platform that is isolated from outside vibrations. (b) Rated Condition: In the standard test circuit shown in Figure 2, the maximum deviation from RIAA frequency response between 20 and 10,000 Hz shall not exceed 2 dB. (c) Reference Signal: Equivalent to 5 cm/sec rms in both left and rig
49、ht channels at 1000 Hz, i.e., a test signal of 2.71 cm/sec rms at 315 Hz would be an acceptable equivalent. 5.1.4.4 Method of Measurement (1) Weighted Signal-To-Rumble Ratio The measurement shall be .made under conditions of: Output voltage, Uo, derived from the reference signal of the test record, as measured. Output voltage, U, derived from the unmodulated groove of the test record, as measured. Measurement shall be made for both left and right channels. The signal-to-rumble ratio for both left and right channels in (dB) = 20logUo U CEA-
