Karaoke. Want to sing songs loudly into the microphone to videos and "backing tracks" from karaoke apps or websites? Here, everything can be organized cheaply and soundly. Affordable portable BT speakers with wireless microphones included (like iconBIT K1000B) have now appeared – the main thing is to make sure that they have new chipsets with a digital (2.4G) radio signal transmission path, and not old analog VHF transmitters. The difference in stability and sound quality will be noticeable to any user. Connect a smartphone to the speaker, launch the desired composition – and sing "together," if necessary with the imposition of effects (echo, reverb, tonal/timbral modulations). Or launch a karaoke video on a TV, projector – just place our speaker nearby, as a "central" vocal channel, "manually" adjust the volume of the TV/speaker to a comfortable balance, and you can have fun. No complicated device pairing is required. Birthdays, parties – at home or outdoors – complete freedom!
A variety of cheap analog radio systems operating in the VHF band are now sold in a similar budget – but in large cities and "noisy" areas, where a lot of equipment and people are concentrated (for example, exhibition pavilions, hotels, offices, apartment buildings, etc.) you may encounter an abundance of interference. Do not forget about drone suppression systems, which operate in a wide range of frequencies. Therefore, digital 2.4G transmitters are preferable for these tasks, although they are usually limited in range to 10-15 meters (which is more than enough for most tasks).
Next, we logically move on to communication with the audience (within a radius of up to 10 meters): conducting excursions, working with volunteers and schoolchildren, speaking at small events. Here, a variety of loudspeakers are traditionally used, and in this "role" the already mentioned autonomous BT speakers with 2.4G microphones have proven themselves perfectly. In addition to "live" communication and broadcasting material from a smartphone, you can play prepared audio files from a USB flash drive or SD card. The batteries in the speaker and microphones are enough for several hours of continuous operation.
Most of the questions and doubts begin when preparing a speech in front of a large audience, in some hall or public place. Usually, the equipment for such events is entrusted to professionals, but if you suddenly have to do this, it makes sense to follow the simplest logic. Forget about VHF, you need professional radio microphones operating in the UHF band. If you suddenly decide to buy Chinese models, it makes sense to carefully study their specifications – so that you do not accidentally invade prohibited frequencies (see the memo at the end of this material). Now it is optimal to choose models that support the permitted UHF band of 710-726 MHz, there is the least "noise" there. Radio systems are supplied in several configurations: a station with 1 microphone (or a module with a lavalier microphone), with 2-4-8 microphones – how many you need for simultaneous operation. There are ordinary UHF systems, and True-Diversity (more expensive) – with the use of two modulators (and two antennas) for each channel, which allows you to duplicate signal processing, guaranteeing minimization of interference. Potentially, the more microphones – the more problems, the more difficult it is to find free frequencies for them and guarantee the absence of interference. Therefore, limit their number as much as possible. Can you imagine why professionals are required to set up microphones for 30-40 actors involved simultaneously in a musical on the stage of a theater in the middle of Moscow near the Kremlin?
In recent years, brands such as Shure and Sennheiser have left our market, and in the absence of their representative offices in Russia, gray models from all over the world have begun to be imported uncontrollably, unfortunately, often operating not in certified permitted ranges. So now it is safer to take the Russian "Octava" or Axelvox (I have been working with Axelvox DWS7000HT for a couple of years, everything is stable, and I like the vocal parameters of its microphones, they say that these are AKG clones).
Frequency memo.
VHF (Very High Frequency) - "very high frequency" - the so-called meter range (30-300 MHz), varies from the spectrum of low frequencies (49–108 MHz) to high frequencies (169–216 MHz). For the civil VHF sub-band, radio stations with frequencies of 136-174 MHz are allowed.
UHF (Ultra High Frequency) - "ultra-high frequency" - decimeter range, varies from the lower frequency spectrum (378–512 MHz) to high frequencies (764–870 MHz). For the civil UHF sub-band, frequencies of 403-520 MHz are allocated for portable radio stations. For radio microphones (with a power of up to 50 mW), 470 – 638 MHz are allowed (this is now the most "noisy" spectrum with Chinese products, it is better not to approach the lower borders, there is the Ministry of Internal Affairs of the Russian Federation), and 710 – 726 MHz (the most reliable range among devices certified in the Russian Federation).
Prohibited frequencies:
138-144 MHz – Air and space communication
149-171 MHz – Government communication
148-149 MHz, 171-173 MHz, 450-470 MHz – Ministry of Internal Affairs of the Russian Federation
173-174 MHz – Ministry of Defense of the Russian Federation
328.6-335.4 MHz – Air radio navigation
Alexander Kurilo