EIA４２６B 試験方法
7.2 Test conditions and operator notes
試験条件と注意事項
7.2.1 Each test may be conducted with a fresh sample of the product, or the tests may all be performed on one sample.
各試験はそれぞれ個別の新しいサンプルか、一つのサンプルで共用される。
7.2.2 The loudspeaker shall be tested as the manufacturer specifies it to be used. If no such specification is provided, individual transducers shall be tested on a baffle of reasonable proportions whose area is no less than ten times the nominal area of the transducer. The accelerated life test at continuous power may also be conducted with the tranducers in free air. Complete systems shall be tested intact. The test shall be conducted at an ambient temperature of 25℃
±５℃ and relative humidity of 30% to 80% in a room or enclosure that maintains these conditions and does not change fundamental resonance frequency more than 5%.
スピーカは製造業社指定の仕様状態でテストされる。 もしも条件提示の無い場合はスピーカの１０倍を超えない妥当な面積でのバッフルで試験する。 加速寿命試験はフリーエアーで試験される。環境温度２５℃±５℃、湿度３０％から８０％でＦｏ変化が５％以内の状態で試験される。
7.2.3 If a crossover or filter network is specified by the manufacturer, it shall be installed according to the manufacturers instructions. If no such network is specified, the amplifier and voltmeter shall be connected directly to the loudspeaker terminals.
ネットワーク指定がある場合は、製造業社に指定に従い装着する。 それ以外はアンプ及び電圧計は直接スピーカターミナルに接続する。
7.2.4 Verify that the speaker’s rated impedance complies with EIA-299-A. Calculate the test voltage to be applied to the speaker, using this rated impedance. Test voltage is equal to the square root of the product of the optimum amplifier power and the rated impedance.
ＥＩＡ-２９９-Ａに示された公称インピーダンス計算方法によって確認されたインピーダンス値を使用する。試験電圧は適正アンプ電力と公称インピーダンスとの積の平方根とする。
7.2.5
CAUTION —
WEAR EAR PROTECTION !
High sound levels of annoying signals are produced which can cause hearing damage with prolonged exposure. The operator is advised to wear appropriate protection such as ear plugs, preferably balanced attenuation devices which will still permit the operator to listen critically for distortion or other signs of distress in the device under test.
7.2.6
Test sequence
試験手順
Power compression is the least stressful test and should be run first, followed by the distortion test, with the accelerated life test performed last.
パワーコンプレッションテストは、続く歪テストや 最後の加速寿命試験よりもストレスの少ない試験であり、すばやく行なわれる。
7.3 Section A - power compression
セクションＡ パワーコンプレッション
This procedure tests the degree to which acoustic output of the speaker is compressed at the optimum amplifier power.
この手順書は適正（オプティマム）アンプ電力におけるスピーカ音響出力の圧縮度合いを試験する。
7.3.1 Procedure
Refer to Annex A.1 and A.3, and to the equipment block diagram in Annex B (normative).
7.3.1 Place the microphone in a close-mic. position (refer to Keele paper cited in section 5.3), on axis with its geometric center, and connect the microphone output to the input of the 1/3-octave real time analyzer. Using the switched attenuator, apply the variable rate swept sine wave test signal to the speaker at an amplitude 20 dB below the optimum amplifier power, and record the reference spectrum of the speaker output.
マイクは（Keele Paperセクション５．３参考）、幾何学上の中心で近傍に設置し、その出力は１/３オクターブリアルタイムアナライザーに接続される。 可変減衰器を使用し、適正アンプ電力の２０ｄB低い可変ﾚｰﾄ掃引正弦波を入力し、スピーカ出力の基準スペクトラムを記録する。
7.3.2 Reduce the drive level by 6 dB. Using the switched attenuator, simultaneously raise the amplitude of the test signal by 20 dB and attenuate the output of the microphone amplifier by 20 dB; this applies considerably less than full power to the loudspeaker. The spectrum produced should track the original curve, but should be about 6 dB lower in amplitude, indicating little or no compression taking place. At this time, the operator should listen for distortion; there should be minimal distortion at this reduced power level. If severe distortion occurs, the operator should stop the test, noting the frequency at which the distortion was worst, and should proceed immediately to the distortion test procedure described in section 7.4. If only minimal distortion is heard, the operator should slowly restore the drive level to the maximum value, or until power compression is observed, whichever occurs first. To avoid overheating high frequency drive units, the bursts of test sweeps should be kept brief— only three or four cycles before a pause —
when near full power.
入力を６ｄB落とす。 可変減衰器を使用し、同時に試験信号を２０dB増加し、且つマイクを２０dB減衰する。 この入力はスピーカのフルパワーよりかなり低い。 スペクトラムは元と同じカーブを示すが、６dBひくい筈で、場所により多少もしくはまったく圧縮されない。 ここで、操作員は、この減らした入力レベルでわずかな歪を確認する。 もしも極端な歪を感じた場合は、試験を中止し、どの周波数でどの歪がもっともひどいのかを記録し、速やかにセクション７．４に示す歪試験にうつる。 もしもわずかな歪の場合は、操作員は、最初に確認されたいずれか、最大レベルまたは 確認されたパワーコンプレッション、まで引き上げる。 高域用スピーカの加熱を防ぐ為試験掃引は、最大電力に近づいた時、３から４サイクルで休止し、短時間を保つ。
7.3.3 Repeat the test sweep for one full minute, and then record the output spectrum. If no compression takes place, the displayed amplitude of the measured spectrum will be identical to that of the previously recorded signal at all frequencies. The speaker shall have passed the test if each 1/3 octave band of the displayed spectrum of the full power signal is reduced in amplitude by no more than 6 dB compared to the reference level established in section 7.3.1 from 40 Hz to 10 kHz or through the bandwidth specified by the manufacturer.
一分間保つ試験掃引を繰り返し、出力スペクトラムを記録する。 もし何もコンプレッションが無ければ測定されたスペクトラムの増幅表示は全周波数において事前の記録と等しくなる。 スピーカは、４０Hzから１０ｋHzまでか製造業社の指定帯域において各１/３オクターブ毎のフルパワー入力が７．３．１で設定された基準レベルより６ｄB以上落ちていなければ合格となる。
7.4 Section B —
Distortion
歪
7.4.1 This procedure measures harmonic distortion at the optimum amplifier power using sine wave test signals at 1/3-octave spaced lEG center frequencies.
When a limited frequency range is specified, the speaker need not be tested outside the specified range. The test signals are contained on the EIA compact disc. As with the power compression test, the test signal can be started at reduced level and slowly increased to the maximum. The operator should be particularly careful at frequencies found to be suspect in the power compression test. In general, speakers are likely to have high distortion at the lowest frequency specified and near crossover frequencies in multi-way systems. Continuous sine waves at full power can burn out tweeters in a matter of seconds. Measurements in the tweeters operating range must be made very quickly. Usually, two seconds is all the time needed for the analyzer to settle. If the operator needs to see it again, allow a cool down period of ten seconds or more.
この手順書は１/３オクターブIEG中心周波数における正弦波を使用し適正アンプ電力でのを高調波歪を測定法を示す。もしも帯域指定がある場合はその範囲外は測定する必要は無い。試験信号はEIAのCDに含まれている。 パワーコンプレッションテスト同じように減衰したレベルからゆっくり最大値まで増やしていく。操作員はパワーコンプレッションテストで見つけれた周波数では特に注意する。一般的にスピーカは低い周波数とクロスオーバー周波数付近で高い歪を示す。連続的なフル正弦波入力ではツイータの焼けが問題となる。ツイータ操作域の測定では迅速に行はねばならない。通常全部で２秒が解析に必要。もしも再操作が必要な場合は１０秒以上の冷却期間を置くようにする。
7.4.2 Procedure
Place the microphone in a “close-mid’ position (refer to Keele paper cited in section 5.3), and connect its output to the input of the 1/3-octave real time analyzer. Apply the sequence of sine wave test signals to the speaker at the optimum amplifier power. Within its specified bandwidth, the speaker shall generate harmonics whose RMS sum amplitude is less than that of the fundamental. Using a spectrum analyzer with a “total SPL” display, the harmonic content of the signal will be less than that of the fundamental if the “total SPL” is greater than the amplitude of the fundamental by no more than 3 dB. For speakers with multiple drive units, repeat the procedure with the microphone centered on each drive unit. The speaker shall be considered to have passed this criterion if the “total SPL” displays no more than 3 dB greater amplitude than the amplitude of the fundamental for each frequency tested within its specified bandwidth. For speakers with multiple drive units, each iteration of the test must pass.
マイクは（Keele Paperセクション５．３参考）、幾何学上の中心で近傍に設置し、その出力は１/３オクターブリアルタイムアナライザーに接続される。 適正アンプ電力の掃引正弦波を入力する。指定帯域内において高調波は基本波より小さく無くてはならない。 アナライザーの「Total SPL」を使用し、高調波は基本波より３dBを超えてはならない。複合型のスピーカの場合はそれぞれのスピーカ軸上で繰り返し測定する。 スピーカは、もしも指定帯域内において「Total SPL」が各周波数の基本値より３ｄBを超えなければ合格とする。 複合型のスピーカにおいては各ユニットのテストがそれぞれ合格しなければならない。
7.5 Section C —
Accelerated life test at continuous power
This procedure simulates the working life of the speaker by testing its ability to withstand a test signal at half the optimum amplifier power for an extended duration without suffering an irreversible and unacceptable change in performance parameters or integrity. The speaker is unlikely to fail quickly in this test because it has already been subjected to full-power over the entire frequency range by the previous tests. The criterion for passing this test is that the speaker not acquire a permanent shift in parameters such as free air resonance frequency. Therefore, we will only know that the speaker failed when it has permanent damage. The risk can be reduced somewhat by monitoring the speaker during the test with a spectrum analyzer or by ear and disconnecting the test signal when a change is noted. Permanent shift may or may not have occurred at this point. If it has not, it cannot be assumed that it will either pass or fail the eight hour test. If the speaker does pass this test, then its rating has been verified.
7.5.1 Break-in
Select the calibration sine wave tone on the compact disc, and adjust the amplifier output level to read 3 dB lower than the voltage calculated in paragraph 7.2.4, (i.e. the calculated voltage multiplied by 0.707). Set the compact disc player to repeat the band containing the weighted noise test signal continuously. Apply the break-in signal to the loudspeaker for an uninterrupted period of one hour. At the end of the break-in period, let the magnet structure cool to below 35 degrees C, determine and record the speakers fundamental resonance frequency..
試験前になじませる。 ７．２．４で算出した値の３dB低い値（０．７０７倍の電圧）に正弦波入力値を設定する。 コンパクトデスクの試験信号を連続演奏に設定する。連続１時間動作させる。終了後マグネット温度が３５℃以下に下がるまで待ってFoを測定する。
7.5.2 Test
Select the calibration sine wave tone on the compact disc, and adjust the amplifier output level to read the voltage calculated in paragraph 7.2.4. Set the compact disc player to repeat the band containing the weighted noise test signal continuously. Apply the signal to the loudspeaker for an uninterrupted period of eight hours.
コンパクトディスクの正弦波設定音を選択すし、アンプの出力を７．２．４で算出した値にあわせる。試験信号での連続演奏に設定する。８時間連続で入力する。
7.5.3 After a minimum recovery period of one hour, and after the magnet structure surface temperature has cooled below 35 degrees C, apply a sine wave signal of half the test voltage to the loudspeaker and sweep through the rated bandwidth specified by the manufacturer, or from 40 Hz to 10 kHz if no rated bandwidth is supplied. The loudspeaker shall have passed the accelerated life test if there is no test induced noise or structural damage that render the loudspeaker unsuitable for its intended application, and the fundamental resonance frequency has not dropped more than 10% below the recorded reference frequency.
試験１時間後、マグネットが３５℃以下に冷えるの待って、特に指定のない場合は４０Hzから１０ｋHzまでの、試験の半分の正弦波信号を入力する。
スピーカはもしもノイズや構造的なダメージがなく、Foの変化が１０％以内であれば合格とする。
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Post By：2007-3-30 13:29:06 [只看该作者]
