.

By THOM PRINGLE - Off Duty/Europe/February 73

ALL YOU REALLY NEED for a complete stereo (or 4-channel) system is a receiver and a set of headphones. Few people, however, have systems as limited as this - they usually start with complete systems including at least a turntable, receiver and loudspeakers, then add headphones as an extra.

It's a situation that exists because, no matter how good headphones become, people still consider them as novel accessories.

Headphones are novel not just because they are wearable pieces of hi-fi gear, but because they actually produce a very exciting effect and have unique properties which loudspeakers simply can't match.

And, of course, anyone who takes his audio seriously doesn't feel that his setup is complete unless he can monitor his equipment with headphones, as they do in professional sound studios.
.

The exciting audio effect produced by headphones is the greatest benefit realized from the positioning of headphones during use. This positioning allows sound to be produced with a known relationship to the ears, thereby doing away with orientation problems.

With headphones you can move about or turn your head without losing your perspective. And, with the sound transducers being in the known, controlled environment of a headphone earpiece, there are no walls, people or furniture to affect the sound before it reaches your ears.

In addition, the transducers have to drive only a very small amount of air (the amount in the ear-cup) and can be very efficient with a corresponding improvement in frequency response and distortion. These are areas where loudspeakers have trouble but where headphones are at their best.
.

Probably the biggest advantage of headphones, though, is that they offer privacy to you and those who are near-by. If you have a pair of headphones with isolation-type ear cushions, you can clamp them on and virtually forget about any activity around you.

A good set of fluid-filled ear cushions can offer as much as 40dB of sound isolation - enough to keep you oblivious of anything short of an earthquake. On the other hand, your headphones are sure to win hearty approval from neighbors and family members who don't have the same temperament or taste in music as you.
.

During the past year, little has happened in the headphone business. A few new models have been introduced, including electrostatic, 4-channel and hear-through types, but the field remains generally unchanged. Considering the high quality of headphones which are now available, it doesn't look like there will be any great changes in the immediate future, either.

With headphones, you have eliminated spatial problems in your listening room. Therefore, recordings which are engineered for maximum spatial response will sound different from other recordings.

For example, if the recording engineer sets up two microphones within one foot of each other and aimed about 180° apart the result will be a recording perfectly designed for natural effect with headphones.

That is, when you are listening to this type of recording with headphones, you should experience the effect of actually witnessing the performance. On the other hand, if the microphones were placed near the performers or wide apart, you will experience artificial placement effect which may not be unpleasant but which may seem unnatural or engineered.

A few headphone models have a special "cross-field" circuit which feeds a small amount of each channel's material into the opposite channel thereby alleviating the artificial placement effect. External control units with "cross-field" circuits are also available and can be added to headphones not equipped with the circuitry.
.

High-fidelity headphones have traditionally been designed with large earpieces and special "ear cushions" which encircle the ear to form a tight seal to the head for good audio coupling as well as high isolation.

The problems with this type of design are that the units are usually heavy and provide too much isolation. A lot of people found that they didn't like to wear these models for more than a few minutes because they felt shut off from everything around them.

Therefore, several new headphone models have special lightweight "open-back, hear-through" designs with some type of openings in the earpiece shell. The openings allow external sounds to reach the wearer and, with some models, even allow the wearer to carry on conversations.
.

Manufacturers have gone to a lot of trouble to design headphones to be comfortable since long wearing times are usually involved. The ear cushions may be filled with foam rubber, air or liquid, or may simply be soft pads which rest lightly against the ear.

In any case, it's best to try on any headphones you are considering before buying, especially if you wear glasses. The pad-type ear cushions are highly recommended for those who want to wear their glasses while using headphones.
.

The impedance figures given in the model descriptions are recommended source impedances. That is, they are the output impedances of the equipment to which you should connect the headphones for best performance. If your amplifier or receiver has a headphone jack, the instruction booklet will indicate what impedance headphone works best with your unit.

Most headphones have the same impedance ratings as loudspeakers - 4-16 ohms. Therefore, they can be connected directly to the output of an amplifier without requiring any special equipment.

If you need headphones with higher impedances, you will find that many manufacturers make mid- and high-impedance versions of their headphones - typical ratings are 250, 300, 600 and 10,000 (10k) ohms.
.

Generally, headphones today use dynamic (magnetic) transducers to reproduce the sound. They are, in fact, miniature speakers with exceptionally good specifications. This term "dynamic" is applied to many transducer designs - from metal plates in front of an electromagnet to the high quality units we mentioned above - and sometimes you will have no indication of exactly what kind of a unit you are buying.

But all the leading brands are proud of the progress they have made in transducer design and will often show very detailed cross-sectional diagrams or descriptions of their units so you know exactly what you are getting.

There are also several electrostatic headphones available which offer above-average frequency response and performance characteristics. Working the same way as electrostatic speakers, they produce sound by vibrating a plastic film through the application of electrostatic charges.

Usually, these units require an external power supply but there are a few "self-energizing" models which must be driven with larger amounts of power during operation. Electrostatic headphones are invariably more expensive than their counterparts.

A new technique has been introduced by the Wharfedale people which combines ideas from both dynamic and electrostatic principles. Called "isodynamic," the system consists of an electrically conductive film between two screen-like magnets.

When current flows across the film, force fields are created which move the film to generate sound waves. The system offers excellent frequency response and is an interesting compromise between dynamic and electrostatic designs.
.

Only a few models have referenced frequency response ratings. This means that you are pretty much on your own as far as choosing a set of phones for best performance. If you're considering a model which gives frequency response but doesn't state variation limits, the best idea is to make
a personal listening test and compare the model against several others. Let your ears make the choice.
.

Since most headphones are really miniature loudspeakers it follows that their power handling ability is also reduced. Usually, you'll find that headphones will not accept over 2 watts of power and in many cases much less. So, if you're planning to make your own headphone connections, you'll have to be careful about how much power you feed into the headphones. Most amplifiers have a front-panel headphone jack and you won't have to worry about making any connections, just remember to turn down the volume before plugging in your headset.
.

Some headphones have individual controls mounted right on the earpiece so you don't have to get up from your chair to adjust the balance or tone. And it's rare if you find headphones without a cord and stereo plug already connected.

Most of the cords are coiled so they are more convenient; stretching or retracting by themselves to stay out of your way. There are many accessory units also available to use with your headset - control boxes, amplifiers, and conversion units - all of which can make listening a lot more convenient if you're an avid headphone user.
.

Several 4-channel models are now available. They have two transducers in each earpiece for a total of four, one connected to each of the four channels. Opinions still vary about the advantages of this arrangement - you'll have to judge for yourself. Most of the 4-channel units have a switch which parallels the transducers in each earpiece for stereo operation.
.

.

1. Akai
2. Akai ASE-9S - Stereo dynamic headphone
3. Audiotec
4. Audiotec CES - Stereo electrostatic headphone
5. Clark
6. Clark 100A - Stereo dynamic headphone
7. Clark 200 - Stereo dynamic headphone
8. Clark 250 - Stereo dynamic headphone
9. Clark 300 - Stereo dynamic headphone
10. Coral
11. Coral HP-120 - Stereo dynamic headphone
12. Dokorder
13. Dokorder HS-303D - Stereo dynamic headphone
14. Fisher
15. Fisher HP-70 - Stereo dynamic headphone
16. Fisher HP-100 - Stereo dynamic headphone
17. JVC-IMivico
18. JVC-Nivico STH-2E - Stereo dynamic headphone
19. JVC-IMivico STH-6E - Stereo dynamic headphone
20. JVC-Nivico STH-10E - Stereo dynamic headphone
21. JVC-Nivico 5844 - 4-channel/stereo dynamic headphone
22. JVC-Nivico 5944 - 4-channel/stereo dynamic headphone
23. Kenwood
24. Kenwood HS-1 - Stereo dynamic headphone
25. Kenwood KH-31 - Stereo dynamic headphone
26. Kenwood KH-51 - Stereo dynamic headphone
27. Kenwood KH-71 - Stereo dynamic headphone
28. Koss
29. Koss ESP-6 - Stereo self-energized electrostatic headphone
30. Koss ESP-9 - Stereo electrostatic headphone
31. Koss HV-1 - Stereo dynamic headphone
32. Koss K-2+2 - 4-channel/stereo dynamic headphone
33. Koss K-6 - Stereo dynamic headphone
34. Koss K-6LC - Same as Koss K-6 except has individual volume control on each earpiece.
35. Koss K-6LCQ - 4-channel/stereo dynamic headphone
36. Koss KO-727B - Stereo dynamic headphone
37. Koss KO-747 - Stereo dynamic headphone
38. Koss KO-747Q - 4-channel/stereo dynamic headphone
39. Koss KRD-711 (Red Devil) - Stereo dynamic headphone
40. Koss Pro-4AA - Stereo dynamic headphone
41. Koss Pro-5LC - Stereo dynamic headphone
42. Koss Pro-5Q - 4-channel/stereo dynamic headphone
43. Marantz
44. Marantz SD-1 - Stereo dynamic headphone
45. National Panasonic
46. National Panasonic EAH-60 - Stereo dynamic headphone
47. Perpetuum-Ebner
48. Perpetuum Ebner PE KH-10 - Stereo dynamic headphone
49. Pioneer
50. Pioneer SE-20A - Stereo dynamic headphone
51. Pioneer SE-30A - Stereo dynamic headphone
52. Pioneer SE-50 - Stereo dynamic headphone,
53. Pioneer SE-L20 - Stereo dynamic headphone
54. Pioneer SE-L40 - Stereo dynamic headphone
55. Sansui
56. Sansui SS-2 - Stereo dynamic headphone
57. Sansui SS-10 - Stereo dynamic headphone
58. Sansui SS-20 - Stereo dynamic headphone
59. Sharp
60. Sharp HP-300 - Stereo dynamic headphone
61. Sharpe HA-10/Mk II - Stereo dynamic headphone
62. Sharpe HA-660/Pro - Stereo dynamic headphon
63. Sony
64. Sony DR-5A - Stereo dynamic headphone
65. Sony DR-7 - Stereo dynamic headphone
66. Stax SR-3 - Stereo electrostatic headphone
67. Stax SR-X -Stereo electrostatic headphone
68. Superex
69. Superex PEP-77D - Stereo electrostatic headphone
70. Superex PEP 79 - Stereo electrostatic headphone
71. Superex QT-4 - 4-channel/stereo dynamic headphone
72. Superex SST - Stereo dynamic/ceramic headphone
73. Superex ST-F - Stereo dynamic headphone
74. Superex Pro-B VI - Stereo dynamic headphone
75. Superex ST-V - Stereo dynamic headphone
76. Superex SW-2 - Stereo dynamic headphone
77. Teac
78. Teac HP-101 - Stereo dynamic headphone
79. Teac HP-102 - Stereo dynamic head phone
80. Telefunken
81. Telefunken TH 30 - Stereo dynamic headphone
82. Telefunken TH 40 - Stereo dynamic headphone
83. Toshiba HR-40 - 4-channel/stereo dynamic headphone
84. Toshiba HR-50 - Stereo dynamic headphone
85. Toshiba HR 80 - Stereo dynamic headphone
86. Wharfedale
87. Wharfedale DD1 - Stereo dynamic headphone
88. Wharfedale Isodynamic - Stereo isodynamic headphone

.

.

.