继续补充 SONY MDR 7506 测量值 — 麦文学看图说话系列

继续补充 SONY MDR 7506 测量值 — 麦文学看图说话系列

不少拥有 SONY MDR 7506 这个重新发现的神器的读者, 也许会好奇一些关键点。

比如:

SONY MDR 7506 的 1000 Hz 赫兹 的失真 THD 在什么电平会超过 0.1%

图中就是这个转折点的电压 100mV RMS, 100 毫伏有效值(1000Hz)以后 SONY MDR 7506 的 THD 就会明显上升。

如果希望测试结果好看, 可以参考俺上一篇散文:麦文学:有图有真相?耳机测试结果如何造假举例 — 麦文学看图说话系列​zhuanlan.zhihu.com

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这个转折点的电压 100mV RMS (100 毫伏有效值) 有啥意义呢?

这又会牵涉到 “推力” 这个几十年来争议不断的话题, 俺就不在这里扯 “推力”了。感兴趣的同学敬请参考另一篇散文:麦文学:推力单位的诞生(上) — 麦文学ver猪.2019 我读书少您别耍我系列​zhuanlan.zhihu.com

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一般来说, 烧友希望自己的耳机失真越少越好, 即便人类只能侦测到 0.3%.

100mV RMS (100 毫伏有效值)的时候, SONY MDR 7506 典型的THD不到 0.1%.麦文学:现在的音量相当于多少分贝?– 麦文学看图说话系列​zhuanlan.zhihu.com

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麦文学:再次转发WHO的新闻 (全球)11亿人面临听力损失风险 当然也因为耳机​zhuanlan.zhihu.com

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您觉得这个听音的电平合适吗?

世界卫生组织也就是 WHO (谁?) 了, 推荐的听音声压最好不要超过 85dB SPL re 20uPa.

当然, 祖国的噪音保护条例也许为了照顾烧友,宽松了许多, 推荐值是不要超过 90dB.

好了, 那 90dB SPL re 20uPa 的时候, 失真又是多少呢? 请看图

开心不开心,意外不意外, 惊喜不惊喜?

听音电平降低一点, 更高保真了。

好了, 也许有同学纠结 SONY MDR7506 的阻抗-频率 (Impedance vs Frequency) 的变化关系。 俺也测了一下, 欢迎大家踊跃点赞, 踊跃赞赏。

看到了吧, 最大值不超过 120 OHM, 最小值不低于 70 OHM.

详细结果如下

Impedance values for 479 frequencies

Frequency(Hz) Magnitude(ohms) Phase(deg)

19.958 78.298 12.756

20.325 78.629 12.969

20.691 78.935 13.183

21.057 79.356 13.322

21.423 79.591 13.478

21.790 80.032 13.659

22.156 80.311 13.758

22.522 80.742 13.935

22.888 81.056 14.144

23.254 81.481 14.339

23.621 81.886 14.478

23.987 82.345 14.538

24.353 82.631 14.703

24.719 83.123 14.838

25.085 83.492 15.022

25.452 83.979 15.090

25.818 84.389 15.186

26.184 84.754 15.307

26.550 85.260 15.466

26.917 85.626 15.501

27.283 86.233 15.563

27.649 86.775 15.715

28.015 87.172 15.735

28.381 87.606 15.862

28.748 88.040 15.915

29.114 88.608 15.931

29.480 89.132 15.966

29.846 89.534 16.048

30.212 90.302 16.103

30.579 90.717 16.083

30.945 91.172 16.126

31.311 91.700 16.160

31.677 92.334 16.199

32.227 93.198 16.121

32.776 93.871 16.087

33.325 94.832 16.021

33.875 95.559 15.980

34.424 96.496 15.872

34.973 97.327 15.865

35.522 98.283 15.726

36.072 99.123 15.550

36.621 99.930 15.360

37.170 100.800 15.213

37.720 101.752 15.002

38.269 102.601 14.817

38.818 103.379 14.582

39.368 104.277 14.300

39.917 105.069 14.114

40.466 105.833 13.786

41.016 106.764 13.530

41.565 107.525 13.248

42.114 108.293 12.895

42.664 109.078 12.500

43.213 109.727 12.236

43.762 110.418 11.849

44.312 111.320 11.419

45.044 112.101 10.933

45.776 112.840 10.413

46.509 113.593 9.875

47.241 114.381 9.237

47.974 115.023 8.676

48.706 115.715 8.123

49.438 116.214 7.552

50.171 116.707 6.898

50.903 117.148 6.385

51.636 117.493 5.660

52.368 117.624 5.107

53.101 118.072 4.519

53.833 118.142 3.981

54.565 118.386 3.307

55.298 118.453 2.803

56.030 118.632 2.191

56.763 118.564 1.680

57.678 118.396 1.058

58.594 118.601 0.347

59.509 118.362 -0.335

60.425 118.342 -1.022

61.340 117.783 -1.723

62.256 117.509 -2.217

63.171 117.076 -2.986

64.087 116.794 -3.439

65.002 116.249 -4.028

65.918 115.666 -4.525

66.833 115.091 -5.002

67.749 114.524 -5.486

68.665 113.932 -5.953

69.580 113.374 -6.339

70.679 112.466 -6.787

71.777 112.086 -7.283

72.876 111.161 -7.653

73.975 110.474 -8.018

75.073 109.929 -8.342

76.172 109.072 -8.720

77.271 108.449 -9.011

78.369 107.474 -9.308

79.468 106.988 -9.620

80.566 106.227 -9.900

81.665 105.596 -10.053

82.764 104.841 -10.255

84.045 104.042 -10.528

85.327 103.483 -10.660

86.609 102.703 -10.915

87.891 102.010 -11.001

89.172 101.244 -11.207

90.454 100.699 -11.248

91.736 99.943 -11.429

93.018 99.346 -11.493

94.299 98.682 -11.615

95.581 98.200 -11.623

97.046 97.489 -11.728

98.511 96.936 -11.783

99.976 96.429 -11.852

101.440 95.806 -11.911

102.905 95.210 -11.903

104.370 94.689 -11.927

105.835 94.239 -11.883

107.300 93.571 -12.010

108.948 93.177 -11.954

110.596 92.675 -11.940

112.244 92.116 -12.018

113.892 91.609 -11.894

115.540 91.121 -11.921

117.188 90.762 -11.868

118.835 90.240 -11.860

120.483 89.888 -11.821

122.314 89.445 -11.704

124.146 89.040 -11.681

125.977 88.570 -11.635

127.808 88.228 -11.583

129.639 87.920 -11.519

131.470 87.487 -11.499

133.301 87.105 -11.372

135.315 86.771 -11.283

137.329 86.442 -11.187

139.343 86.078 -11.122

141.357 85.820 -11.036

143.372 85.410 -10.992

145.386 85.042 -10.861

147.583 84.795 -10.829

149.780 84.469 -10.658

151.978 84.233 -10.579

154.175 83.959 -10.502

156.372 83.725 -10.413

158.569 83.430 -10.323

160.950 83.129 -10.201

163.330 82.925 -10.107

165.710 82.659 -9.930

168.091 82.413 -9.836

170.471 82.263 -9.656

173.035 81.970 -9.617

175.598 81.717 -9.457

178.162 81.589 -9.380

180.725 81.347 -9.218

183.289 81.168 -9.144

186.035 80.939 -8.994

188.782 80.774 -8.888

191.528 80.657 -8.695

194.275 80.384 -8.588

197.021 80.321 -8.508

199.951 80.171 -8.330

202.881 80.030 -8.188

205.811 79.889 -7.989

208.740 79.829 -7.825

211.853 79.730 -7.692

214.966 79.701 -7.517

218.079 79.725 -7.377

221.191 79.608 -7.266

224.487 79.645 -7.191

227.783 79.764 -7.071

231.079 79.742 -7.084

234.375 79.745 -6.942

237.854 79.820 -6.974

241.333 79.822 -6.985

244.812 79.774 -6.978

248.291 79.726 -7.037

251.953 79.601 -7.116

255.615 79.530 -7.151

259.277 79.410 -7.165

263.123 79.310 -7.226

266.968 78.992 -7.250

270.813 78.793 -7.232

274.841 78.611 -7.184

278.870 78.367 -7.188

282.898 78.026 -7.116

286.926 77.901 -6.993

291.138 77.717 -6.900

295.349 77.487 -6.780

299.561 77.432 -6.724

303.955 77.234 -6.660

308.350 77.099 -6.508

312.744 76.953 -6.418

317.322 76.788 -6.307

321.899 76.697 -6.199

326.660 76.609 -6.131

331.421 76.495 -6.034

336.182 76.423 -5.850

341.125 76.266 -5.820

346.069 76.139 -5.741

351.013 76.104 -5.559

356.140 76.074 -5.509

361.267 75.871 -5.387

366.577 75.845 -5.260

371.887 75.811 -5.224

377.380 75.716 -5.071

382.874 75.549 -4.998

388.367 75.453 -4.882

394.043 75.411 -4.863

399.719 75.350 -4.659

405.579 75.296 -4.632

411.438 75.213 -4.578

417.480 75.167 -4.406

423.523 75.114 -4.294

429.749 75.086 -4.216

435.974 75.029 -4.141

442.383 74.965 -4.060

448.792 74.868 -3.910

455.383 74.895 -3.825

461.975 74.759 -3.744

468.750 74.762 -3.739

475.525 74.743 -3.566

482.483 74.659 -3.456

489.441 74.608 -3.363

496.582 74.589 -3.275

503.723 74.442 -3.194

511.047 74.546 -3.098

518.555 74.387 -3.024

526.062 74.333 -2.909

533.752 74.366 -2.834

541.443 74.276 -2.726

549.316 74.244 -2.610

557.373 74.273 -2.580

565.430 74.216 -2.469

573.669 74.148 -2.391

582.092 74.092 -2.284

590.515 74.116 -2.188

599.121 74.050 -2.141

607.910 74.057 -2.040

616.699 73.913 -1.976

625.671 74.029 -1.856

634.827 73.913 -1.746

643.982 73.882 -1.655

653.320 73.954 -1.603

662.842 73.885 -1.488

672.546 73.864 -1.404

682.251 73.816 -1.308

692.139 73.875 -1.175

702.209 73.818 -1.155

712.463 73.814 -1.010

722.900 73.734 -0.909

733.337 73.831 -0.889

743.958 73.734 -0.784

754.761 73.767 -0.687

765.747 73.861 -0.497

776.917 73.723 -0.464

788.269 73.791 -0.420

799.805 73.757 -0.269

811.523 73.799 -0.092

823.242 73.762 -0.135

835.144 73.804 -0.018

847.229 73.817 0.056

859.497 73.782 0.142

871.948 73.802 0.304

884.583 73.846 0.383

897.400 73.812 0.426

910.400 73.825 0.538

923.584 73.821 0.570

936.951 73.785 0.701

950.500 73.781 0.828

964.417 73.828 0.879

978.516 73.851 0.968

992.798 73.789 1.096

1007.263 73.887 1.228

1021.912 73.974 1.318

1036.743 73.992 1.361

1051.758 73.921 1.489

1067.139 73.977 1.541

1082.703 74.035 1.649

1098.450 74.100 1.743

1114.380 74.123 1.858

1130.676 74.194 1.941

1147.156 74.259 1.979

1163.818 74.369 2.084

1180.664 74.377 2.172

1197.876 74.351 2.239

1215.271 74.450 2.302

1233.032 74.425 2.359

1250.977 74.368 2.436

1269.104 74.331 2.493

1287.598 74.342 2.661

1306.274 74.410 2.766

1325.317 74.505 2.933

1344.543 74.518 3.020

1364.136 74.622 3.105

1383.911 74.690 3.187

1404.053 74.696 3.285

1424.561 74.791 3.325

1445.251 74.835 3.470

1466.309 74.909 3.613

1487.549 74.923 3.709

1509.155 75.098 3.778

1531.128 75.050 3.883

1553.467 75.110 3.967

1575.989 75.233 4.084

1598.877 75.327 4.302

1622.131 75.371 4.307

1645.752 75.497 4.434

1669.739 75.561 4.540

1694.092 75.522 4.611

1718.811 75.691 4.760

1743.896 75.797 4.890

1769.348 75.914 4.973

1795.166 76.035 5.101

1821.350 76.201 5.224

1847.900 76.291 5.344

1874.817 76.429 5.448

1902.100 76.561 5.523

1929.749 76.742 5.661

1957.764 76.927 5.829

1986.328 77.062 5.864

2015.259 77.292 5.995

2044.556 77.501 6.055

2074.219 77.689 6.142

2104.431 77.952 6.223

2135.010 78.012 6.294

2166.138 78.244 6.314

2197.632 78.345 6.371

2229.675 78.607 6.487

2262.085 78.913 6.512

2295.044 79.133 6.602

2328.369 79.246 6.642

2362.244 79.518 6.706

2396.667 79.736 6.823

2431.458 80.100 6.889

2466.797 80.383 6.936

2502.686 80.714 6.989

2539.124 81.076 7.022

2576.111 81.424 6.980

2613.647 81.858 6.972

2651.733 82.237 6.938

2690.369 82.615 6.873

2729.553 83.012 6.823

2769.287 83.462 6.657

2809.570 83.760 6.474

2850.403 84.185 6.297

2891.785 84.533 6.029

2933.899 84.820 5.752

2976.563 85.098 5.545

3019.775 85.243 5.187

3063.721 85.432 4.785

3108.215 85.224 4.307

3153.442 84.672 3.796

3199.402 81.855 6.031

3245.911 86.334 4.536

3293.152 85.939 3.831

3341.125 85.605 3.449

3389.648 85.211 3.177

3438.904 84.878 2.969

3488.892 84.490 2.758

3539.612 84.244 2.725

3591.064 83.954 2.599

3643.250 83.720 2.642

3696.167 83.446 2.664

3750.000 83.374 2.720

3804.565 83.274 2.753

3859.863 83.292 2.904

3916.077 83.344 2.907

3973.022 83.604 2.879

4030.884 83.875 2.895

4089.478 84.165 2.685

4148.987 84.566 2.363

4209.412 84.784 1.940

4270.569 84.752 1.309

4332.642 84.261 0.666

4395.630 83.508 0.159

4459.534 82.474 -0.250

4524.353 81.504 -0.393

4590.088 80.540 -0.247

4656.921 79.686 -0.140

4724.670 79.021 0.147

4793.335 78.441 0.539

4863.098 77.870 0.860

4933.777 77.576 1.226

5005.554 77.286 1.541

5078.430 77.078 1.844

5152.222 76.917 2.222

5227.112 76.728 2.484

5303.101 76.733 2.762

5380.188 76.616 3.053

5458.374 76.507 3.295

5537.842 76.562 3.437

5618.408 76.398 3.730

5700.073 76.301 3.895

5783.020 76.217 4.103

5867.065 76.177 4.298

5952.393 76.098 4.495

6039.001 75.969 4.730

6126.892 75.945 4.878

6216.064 75.908 5.138

6306.519 75.727 5.408

6398.254 75.690 5.738

6491.272 75.697 5.900

6585.754 75.590 6.149

6681.519 75.618 6.465

6778.748 75.642 6.663

6877.258 75.630 6.918

6977.234 75.673 7.197

7078.674 75.684 7.475

7181.580 75.739 7.702

7285.950 75.776 7.928

7391.968 75.869 8.229

7499.451 75.908 8.370

7608.582 76.097 8.643

7719.177 76.146 8.854

7831.421 76.209 9.070

7945.313 76.325 9.254

8060.852 76.408 9.495

8178.040 76.444 9.770

8297.059 76.589 9.934

8417.725 76.630 10.193

8540.223 76.705 10.502

8664.367 76.817 10.659

8790.344 77.032 10.968

8918.152 77.252 11.130

9047.791 77.451 11.410

9179.443 77.697 11.607

9312.928 77.953 11.783

9448.426 78.147 11.910

9585.938 78.423 12.068

9725.281 78.562 12.155

9866.821 78.814 12.264

10010.376 78.828 12.340

10155.945 78.984 12.472

10303.711 79.056 12.534

10453.491 79.233 12.547

10605.469 79.178 12.638

10759.644 79.224 12.760

10916.199 79.158 12.858

11074.951 79.089 12.981

11236.084 78.967 13.247

11399.598 78.903 13.465

11565.490 78.802 13.798

11733.765 78.848 14.053

11904.419 78.853 14.331

12077.637 79.063 14.632

12253.234 79.151 14.905

12431.396 79.225 15.235

12612.305 79.450 15.524

12795.776 79.572 15.830

12981.812 79.781 16.072

13170.594 79.911 16.320

13362.121 80.111 16.546

13556.396 80.333 16.812

13753.602 80.503 17.073

13953.735 80.783 17.300

14156.616 80.821 17.516

14362.609 81.049 17.731

14571.533 81.230 17.990

14783.569 81.349 18.289

14998.535 81.584 18.523

15216.613 81.709 18.716

15437.988 81.905 18.968

15662.476 81.993 19.305

15890.259 82.328 19.535

16121.338 82.385 19.798

16355.896 82.751 20.150

16593.750 83.025 20.420

16835.082 83.119 20.692

17079.895 83.468 20.952

17328.369 83.762 21.194

17580.506 84.049 21.546

17836.305 84.279 21.712

18095.764 84.544 21.928

18358.887 84.761 22.295

18625.855 84.983 22.546

18896.852 85.252 22.805

19171.691 85.599 23.093

19450.563 85.916 23.368

19733.459 86.262 23.734

20020.568 86.532 23.960

=====================================================

【待续】

【待续】