Audio Accessory

complex audio waveform

The Importance of Good Audio Quality in Amateur Radio

Audio technology in amateur radio covers the processing, reproduction and quality of the audio signal at the receiving and transmitting end. A good modulation quality results in a good speech intelligibility and a pleasant listening impression, brings more success in DX and more QSOs in contest operation.

Newcomer to ham radio have this aspect understandably less in their focus. Other things are more important like the best possible antenna. And at the beginning one is content with the standard hand microphone and any headphone, which is compatible at least in impedance and connection with the transceiver. The only importance seems to be that the stations on the other end is well understood. And obviously one does not hear their own signal. So if the radio partner does not complain, everything seems to be alright. As long as the controls for mic gain and compression on the transceiver are set correctly, this is usually the case.

However, the quality of the voice transmission also depends to a large extent on the correct speaking distance and the frequency response of the microphone. In earlier times, amateur radio operators placed emphasis on modulation that was as sharp as possible with good speech intelligibility, especially for DX operation. External compressors did the rest.

The signals were loud and assertive. Only up to a certain degree was this an advantage with the right settings. Because the intelligibility quickly turned into the opposite. The modulation had little to no dynamics - which does not sound too pleasant!

The digitization of audio technology and the use of extensive DSP technology, as external equipment or integrated into the transceivers, allow numerous possibilities to influence the audio on the receive and transmit side and to adjust levels and frequency response individually. Since then, a "culture" of pleasant and natural sounding audio has taken hold. This can often be observed in some evening rounds in the 80-m-band, where the participants are almost exclusively concerned with setting their equalizers and modulation quality. Likewise, AM is not dead yet! In the 80- and in the 10-m-band there are AM sessions with stations in almost HiFi quality.

In the days of voice radio in amplitude modulation (AM), it was much easier to produce a natural sounding modulation due to the larger available bandwidth of the signal. Today's problem is to get the best possible speech quality out of the bandwidth limitation of 2.7 kHz or even 2.4 kHz in SSB mode.

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.

Icon representing all technologies used for reception of a signal
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.

Icon representing all technologies used for transmission of a signal
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.

Headphones with over ear speakers in a sleek design
ANC

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Info
Quality headset (headphones with boom microphone) with full size over ear protection
VOX

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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.

Desktop Speakers

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.

Mobile Loudspeaker

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.

Audio Filter (Noise Cancelling)

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

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.

Large loudspeaker for radio transmission for better intelligibility

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.

Dynamic Microphone

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.

Condenser Microphone

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.

Electret Microphone

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.

Piezo Microphone (crystal microphone)

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.

Designs of Amateur Radio Microphones

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.

Accessories for Microphones

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
A good microphone is crucial for best audio quality

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.

Equalizer display of signal levels per frequency range

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.

Items 1-10 of 282

  1. Anytone Microphone BT-01 for D578UV
    New
    Anytone Microphone BT-01 for D578UV

    For wireless operation of the AT-D578UV mobile device, with large 2.2" display, Bluetooth, USB

    Not in stock, back on: 15.12.2022

    €198.00
    incl. VAT plus shipping €166.39
    SKU BT-01
  2. 4O3A Noise Cancelling Headset NC-1 BT
    New
    4O3A Noise Cancelling Headset NC-1 BT

    High quality headset with active noise cancellation, usable via Bluetooth or with cable

    Not in stock, back on: 30.01.2023

    €309.00
    incl. VAT plus shipping €259.66
    SKU 4O-NC-1
  3. Icom HS-95LWP Headset Back Head
    New
    Icom HS-95LWP Headset Back Head

    Suitable for various Icom handheld radios with VOX function

    Not in stock, back in 20 days.

    €206.50
    incl. VAT plus shipping €173.53
    SKU HS-95LWP
  4. Icom Microphone HM-222HLWP
    New
    Icom Microphone HM-222HLWP

    With additional 3.5 mm jack socket, suitable for various Icom handheld radios

    Not in stock, back in 20 days.

    €129.50
    incl. VAT plus shipping €108.82
    SKU HM-222HLWP
  5. Microphone adapter/extension IC-705
    New
    Microphone adapter/extension IC-705

    Two adapter cables for IC-705 Mic/SP connections, approx. 20 cm.

    Not in stock, back on: 09.12.2022

    €14.90
    incl. VAT plus shipping €12.52
    SKU 40080.MAD705
  6. Phonema Miranda-S Station Speaker
    New
    Phonema Miranda-S Station Speaker

    High-quality processed loudspeaker, optimized for SSB, interior insulation.

    In stock, shipped in 3 to 4 days.

    €169.00
    incl. VAT plus shipping €142.02
    SKU MIRANDA-S
  7. Yaesu Microphone M-70
    Yaesu Microphone M-70

    Desktop microphone with electret (condenser) capsule, PTT/lock, filter, cable

    In stock, shipped in 3 to 4 days.

    €159.00
    incl. VAT plus shipping €133.61
    SKU M-70
  8. Heil Sound Pro7
    Heil Sound Pro7

    Headset with exchangeable microphone capsule and large Gel ear pads, detachable cable.

    Please select a product

    As low as: €299.00
    incl. VAT plus shipping €251.26

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