USB 2.0
The number of USB 2.0 ports provided by the projector.
Do not confuse these connectors with USB slave (see "Management ports") — in this case we are talking about
USB ports for various peripherals. Most often, these ports are used for direct playback of content from flash drives and other storages (for example, external HDDs). At the same time, we note that video viewing is not available in some projectors (only photos), in others a very limited set of formats may be supported. However, a direct connection is often more convenient than viewing through a computer or other device. The USB ports can also be used for other purposes, such as updating firmware, transferring files between a flash drive and the projector's built-in storage, or even for keyboards/mouses (in Android devices, see above).
The USB 2.0 standard itself is considered obsolete, but it is quite enough for projectors, and newer peripherals are fully compatible with such connectors. At the same time, you rarely have to connect more than one external device to the projector at a time, so there are few models with more than one USB 2.0.
Number of speakers
The number of built-in speakers provided in the projector.
The
presence of speakers in itself allows user to play sound (for example, accompaniment to the displayed video) without speakers and other additional equipment. However the quality of such sound usually turns out to be low; for a clear sound, you still need external sound system. However, in some cases this is quite enough; in addition, there are projectors with advanced built-in speakers.
The number of speakers can be one or two. In the first case, we are talking only about the playback of monophonic sound, without any surround effect. And two speakers already represent a stereo system. The subwoofer is considered a separate function and does not affect the number of speakers in this paragraph.
Sound power
The nominal power of the sound system installed in the projector.
The higher this power, the louder the sound the device can produce, the better it will be heard in a large room and/or noisy environment. At the same time, it is worth noting two nuances. First, built-in speakers are usually made relatively low-power — otherwise they would take up too much space. Secondly, most modern projectors allow the connection of external sound system (see "Audio connectors"), more powerful than the built-in one. So it makes sense to pay attention to this indicator if you initially plan to use the "native" sound of the projector. Detailed recommendations on the required power for certain conditions can be found in special sources.
HDMI inputs
The number of HDMI inputs provided by the projector.
HDMI is a comprehensive digital interface originally designed for high-definition video and multi-channel audio. Today, it is actually a generally accepted standard, outputs of this type are available in the vast majority of HD-enabled video devices — media centers, Blu-ray players, computer graphics cards, etc. The presence of several HDMI inputs allows you to simultaneously connect several signal sources to the projector and switch between them in the projector settings without having to connect and disconnect cables.
Power consumption
The power consumed by the projector during normal operation. Both the high consumption of the device and the requirements for power supply providing depend on this indicator: for example, heavy professional projectors of 3500 W and above cannot be plugged into standard sockets, they require a special connection format.
Keep in mind that when using traditional mercury or gas discharge lamps, high brightness inevitably requires high power. Energy efficient LED projectors do not have this disadvantage, but they are still relatively uncommon, and LED is not always a suitable type of lamp.
