Wireless Microphone Test Methods

In Our Modern cultural life, The wireless microphone will been used in many place. However, people still don't know much about how to choose a best wireless microphone, such as the effective working distance, people always think that greater RF power make the working distance farer. But It be found in the actual work is often not the case. In addition, manufacturers release of technical indicators, sometimes puzzling.

We have Thousands wireless microphone manufacturer, but There is no essential difference between their products. Many of those products have a good technical indexes, but actual it's unsatisfactory when we use it. It is a big problem to testing the technical indexes of the wireless microphone, as many of us don't have the full set of measuring instruments as radio laboratory, Testing can't doing. That led to the error choice of wireless microphone: I saw you use it so I use it too. we don't care which place to use which kind of microphone. If conditions are not so harsh or critical, is generally not a major problem, especially in the channel selection was then. However, in actual use, particularly in the non-fixed installations, such as the shooting television programs mobility case of large, difficult to predict the ambient conditions, the receiver changes from often, and sometimes does not exceed the technology used in wireless microphone range of indicators, but the situation has deteriorated to receive the results crew was forced to shut down adjustment, or reconsider pickup program, or even replace equipment.

For these situations, some recent television journalists on the daily work of the sound of several commonly used wireless microphone for a detailed and practical tests. Wireless microphone pickup involves not only the distance problem, but the sound quality issues involved, including distortion, noise, interference, stability and so on.

Test

The entire test is conducted in a television production units, mainly concentrated in the TV sound actual work needs, such as equipment performance, mimicking the actual work environment, working distance, the sound waveform display, subjective assessment of sound quality and other projects. This article is only L and S groups selected wireless microphone distance tests are introduced.

Test Method roughly like this: For the above two sets of wireless microphone receiver placed on the same point, the two sound engineers were carrying two different types of emission units, namely transmitter lavalier microphone head, transmitter or external plug handheld microphone. The same route between the prescribed movement, continuously available in the mobile location description and other voice information. Receiving unit respectively will each received signal into the two inputs of the mixer, the mixer output to the sub-track digital audio workstation for real-time sub-track recording to record and field analysis.

The first set of tests

Are taking the line shown in Figure 1, the starting point for placing the receiver position, the end is the north doorway.

Products tested are: (1) S version xxxx (RF power 250mW), using S brand lavalier microphone head, the receiver is Sanken3xxx type, use the machine's microphone output port. (2) L Brand MM4xx (RF power 100mW, 400 Series Digital coupling platform), use CountrymanBx microphone head, the receiver for the same brand UCR4xx type, use the machine microphone output port.

Figure 1 Schematic wireless microphone measured route

During the synchronization process, S 170m or so in the case of unshielded deadening frequency loss phenomenon occurs, and then move around 5m absolutely no signal, see Figure 2 (lower): L a 212m or so into the North openings, as Shielding is very serious and appears to run frequent phenomenon, see Figure 2 (above). Figure 2 coordinates the same time, part of the waveform is interrupted as a result in favor of the non-running frequency received signal can be seen. L The reception is much better than S.

Figure 2 receiver microphone output waveform (for the L plates, under the S card)

The second set of tests

Are taking the line shown in Figure 1, the starting point for placing the receiver position, the end is the north doorway. Products tested are: (1) L Brand UM2xx (RF power 250mW, 200 Series Analog RF platform), use CountrymanBx microphone head, the receiver is an L license R4xx type, using 200 series compatible receiving mode and line output (4dBu) port . (2) L Brand MM4xx (RF power 100mW, 400 Series Digital coupling platform), use CountrymanBx microphone head, the receiver is L plates UCR4xx type, coupled with 400 series digital reception mode and line output (4dBu) port.

To note here is that the first set of tests using a mixer's microphone input, this is because in many cases, users are willing to replace the wired microphone wireless microphone. However, we found that, for high-sensitivity receiver, the gain must be lowered to match the back of the device input indicators. If the match properly, it may occur in the signal limiter large explosion caused by sound. Thus, the second set of tests were converted to two line output of the receiver output. From the displayed waveform audio workstation to see, even in large individual voices when the signal clipping phenomenon did not occur.

L plates UM2xx and L plates MMxx doorway into the North, due to the emergence of a serious run frequency shielding phenomenon. But still, after passing through the north doorway signal, during a distance of about 247m, just inside the doorway in the North before the run frequency. Tests show that: L Brand MM4xx run frequently appears before working distance far beyond the first set of test data.


The third set of tests

Are taking the line shown in Figure 1, the starting point for placing the receiver position, the end is the north doorway. Products tested are: (1) L Brand UH2xx (RF power 100mW, 200 Series Analog RF platform, external plug-in transmitter), the use of front-end microphone brand 4xx S dynamic microphone, receiver for the L plates R4xx type, the use of 200 series Compatible receive mode and line output (4dBu) port. (2) L Brand LMxx (RF power 50mW, 400 Series Digital coupling platform), use CountrymanBx microphone head, the receiver for the L plates UCR4xx type, coupled with 400 series digital reception mode and line output (4dBu) port.