Audio accessories are very diverse
Our category "Audio Accessories" contains many different products around the topic of hearing and being heard. We want to give you a short overview of what you can find in this category and which purposes the products have, making the technical data and features roughly comparable.
Audio Technology for Reception
The assortment contains everything that can be used from the audio output. Starting with a variety of headphones and external table or mobile speakers, NF-DSP modules. Digital audio filters provide further improved audio quality. Adapter cables, NF switchers provide the right connection.
Audio Technology for Transmitting
This category includes essential accessories for use on the transmitting side. Handheld microphones, desktop microphones for stationary use and professional headsets are the first prerequisite for good audio quality of the transmit signal. Audio equalizers are the ultimate to give the audio quality the final touch.
Headphones for Amateur Radio
The electromechanical headphone with steel diaphragms and premagnetized coils is still known from the time of detector receivers and steam radios. With its limited frequency range and its high impedance of 2 to 4 kOhm, it has not been manufactured for a long time. In terms of frequency response, it is at best still suitable for reproducing Morse code. In addition, its unpadded earcups are very uncomfortable to wear.
The electrodynamic headphones, which work analogously to the electrodynamic loudspeaker with plunger coils in the field of permanent magnets, have prevailed and are still the most widely used today. It is inexpensive to manufacture and uncomplicated to use in practice. With a correspondingly high construction effort, it enables a high reproduction quality.
Furthermore, a distinction must be made between open and closed headphones. Open headphones rest with the surface of the earcups on the ears (on-ear), usually have a lighter construction and therefore offer a high wearing comfort. However, their good surround sound plays a subordinate role in radio applications, because the sound quality in amateur radio is unequal to the requirements of a music hi-fi noble sound. Outside noise is not attenuated, which can be bothersome or desirable depending on the situation.
Closed headphones have a larger design and a higher weight due to the outwardly insulated earcups. Close-fitting earcups that enclose the ear (over-ear) block out ambient noise as far as possible and allow concentration on the listening experience and quiet signals. Earplugs also belong to this product group. For contest participants and especially for DX expeditors, closed-back headphones are indispensable for working through pileups in noisy environments. Earphones (in-ear) and lightweight behind-the-head headsets are recommended for mobile and portable use with handheld radios.
Standard connections on the headphones are 6.3- or 3.5-mm stereo jacks. The headphone sockets on receivers and transceivers are wired on current units to allow mono playback with the headphone plugs wired for stereo. For mobile or portable use, there are also cordless headphones that rely on wireless connection via Bluetooth and represent real added value for these applications.
In line with the usual low-impedance audio outputs of current receivers and transceivers, electrodynamic headphones have a connection impedance of between 4 and 100 ohms.
ANC
What’s that?
Info
VOX
What’s that?
Info
HeadSETS – More Than Headphones
Originally developed as a combination of a closed headphone with a microphone as a headset for the pilots' flight radio, and equipped with the ANC function, a headset is an effective means against the ambient noise during multiband operation of a DX or contest station. Even without the support by means of ANC, already the closed and damped earcups unfolded a pleasant attenuation of the ambient noise. Usually, the PTT is operated with a footswitch or controlled via VOX when using a headset. VOX only works in quiet environments, of course. This leaves the hands free for operating the radio station and entering the connection data into the logbook program.
With the microphone of a headset it depends on the fact that it possesses a directional characteristic as narrow as possible, directed only to the front, so that ambient noises are not transmitted at all or only clearly weakened.
LOUDspeakers for Amateur Radio
The electrodynamic principle of the plunger coil loudspeaker has also prevailed in loudspeakers and is the most common, along with a few other systems for special applications.
For obvious reasons, the speakers built into receivers and transceivers can only ever be relatively small. A fuller audio quality is always provided by an external auxiliary speaker. These are available as desktop speakers in design and housing dimensions matching the respective transceiver models as device-specific accessories. If the impedance and maximum permissible power are suitable, other brands can of course also be connected.
Well-equipped desktop speakers have integrated, adjustable audio filters, as well as two inputs for the switchable connection of two audio sources. To avoid self-resonance of the speaker cabinet and for a perfect sound, it is recommended to fill the interior with an insulating material. For this purpose, damping modules are recommended, which are offered by Phonema as retrofit kits for already existing station loudspeakers. These suitably cut-to-size retrofit kits are available for a whole range of Icom, Kenwood and Yaesu device-mounted station loudspeakers.
The two-wire speaker connection cables usually consist of a red wire (positive terminal) and a black wire (negative terminal), but since the audio signal is AC, wouldn't it really matter? Although a loudspeaker seems to work properly either way, there is still a reason with the marked polarity! The dome and membrane of the loudspeaker should always move forward with the amplitude of the positive half wave. This is only the case with correct connection according to the specified colors red and black!
Tip
The impedance of the audio source and the loudspeaker should be approximately identical. In case of deviations an optimal power transmission and conversion into sound is no longer given. The result would be a deteriorated audio quality due to distortions. A significant exceeding of the maximum power handling capacity of the loudspeaker leads to an irreparable destruction of the dome and/or the loudspeaker membrane at the latest at maximum volume.
A mobile loudspeaker improves intelligibility and thus also safety when driving. It can usually be placed in an acoustically optimal position, while the possible position of the mobile device via the built-in speaker often does not allow good audio reproduction. If the mobile device is in a slot, a separate speaker is required anyway. Mobile speakers have a mounting bracket that allows them to be mounted in an adjustable position, at least in terms of orientation.
In addition to the filter and selection options already integrated in the transceiver, external analog and digital audio filters make it possible to influence the AF spectrum of the receiver, to selectively filter out (peak filter) or blank out (notch filter) sounds, to reduce noise or to blank out impulse noise (noise blanker). In the most sophisticated digital version, these devices, such as those offered by bhi, are called equalizers.
Parametric equalizers from bhi or W2IHY with integrated AF amplifier give the user the possibility to define any frequency range and to raise or lower it in amplitude. Within the LF spectrum, each frequency can be precisely adjusted. This means that the entire course of the LF spectrum can be precisely adjusted to the operator's listening habits. The levels of unwanted, problematic frequencies can be lowered and preferred frequency ranges can be raised in level. With well thought-out settings, this results in a clear and pleasantly audible audio signal with significantly improved intelligibility.
The bhi equalisers are used to improve reception, while W2IHY's products are used to improve the modulation on the transmit side.
Furthermore, some models have the Bluetooth (BT) function and a DSP noise reduction on board. The Bluetooth function enables wireless connection with BT speakers or BT headsets. A digital noise reduction, which is also known from many other bhi products, reduces the noise on the transmission channel very effectively.
Microphones for Amateur Radio
The key with microphones for amateur radio is that they preferentially transmit the audio spectrum up to a maximum of 3000 Hz for optimum speech intelligibility. The frequencies above this do not contribute anything to further improving speech intelligibility. This frequency response, which is reduced to the speech spectrum, is the difference to microphones used to transmit music or vocals in hi-fi quality.
A dynamic (plunger coil)
microphone uses electromagnetic induction to convert sound pressure pulses into equivalent electrical voltage pulses. A coil permanently connected to the diaphragm moves in time with the sound pulses with an extremely small air gap across a permanent magnet. It is virtually the reverse of the function of a dynamic loudspeaker. Dynamic microphones emit a powerful sound image that favors the low and mid frequencies.
A condenser microphone utilizes capacitance changes between its moving diaphragm and a counter electrode. The condenser microphone is very sensitive and favors slightly more the higher frequencies of the audio spectrum. However, it requires integrated electronics and a power supply to operate and convert the capacitance changes into electrical pulses.
The electret microphone, or more accurately electret condenser microphone, is a special type of condenser microphone. Thanks to their compact design and good signal quality, electret microphones are offered in large numbers. These microphones do not require an operating voltage themselves; only the necessary impedance converter requires a voltage supply of about 1.5 V.
The crystal microphone transmits sound from the diaphragm to a piezoelectric element, a crystal, usually made of lead zirconate titanate. Quartz crystals emit a small voltage across the diaphragm under the influence of sound pressure - the so-called piezoelectric effect. As with the condenser microphone, the output voltage equivalent to the audio signal must be amplified by an amplifier integrated into the microphone, which means that an operating voltage is required.
Microphones are available as hand-held microphones, as desktop-microphones with a fixed orientation or with a flexible orientation using a gooseneck. The most widespread are dynamic microphones in the designs as stand microphones or larger handheld microphones, as well as electret microphones in small handheld microphones and headsets. A special form is the loudspeaker microphone, which is often used with an integrated small loudspeaker on handheld radios or in mobile operation.
The qualities of a good microphone often only come into their own with good accessories: professional shock absorber mounts in the form of microphone bellows or spiders allow perfect suspension of microphones and eliminate contact noise, table vibrations and impact sound. A windscreen prevents unwanted hissing noises when the speaking distance to the microphone is too short.
Adapter cables expand the connection options. Last but not least, there are also replacements for the foam pads of the earcups, which have become grubby or porous over the years.
A sufficient speaking distance and a sideways microphone pickup largely avoid the unwanted sibilance!
Tip
Audio equalizer
One thing has to be said up front: Improving the transmit audio with the use of an audio equalizer only works and makes sense together with a good microphone!
A audio equalizer on the transmit side (W2IHY, MetroPWR...) allows comprehensive control of the sound characteristics and influence on the frequency response of the microphone. Thus, an unfavorable voice pitch, with too much highs or lows, can be largely changed towards a better intelligibility. The noise gate function allows background and ambient noise to be suppressed. Other features of an equalizer that can be used on the transmitting side are "compressor", "limiter" and the "expander" that reduces background noise.
The world of audio in amateur radio is much bigger than you think. Experience a pleasant audio quality - also in amateur radio - and make your transmit signal the flagship of your station.
ACTIVE NOISE Cancelling
ANC is short for "Active Noise Cancelling", and is the system of noise-canceling headphones that electronically eliminates ambient noise. For this purpose, one or more integrated microphones pick up the ambient noise, this signal is phase-shifted by 180 degrees and fed back with the same high amplitude. The digital electronics are integrated into the headphones. Through this "trick", this signal and the associated external noise almost cancel each other out within the closed shells of the headphones.
A voice-controlled switch known as a voice operated exchange (VOX) is typically used on half-duplex radios. The physical push-to-talk (PTT) button on the radio is functionally replaced by VOX, which also offers a hands-free communication option. Starting and stopping audio recordings is another use for VOX.
