Zombie Apocalypse Movie Theater, Part II

 A guest post from the Realist.

Post apocalyptic movie theater set up inside an
abandoned warehouse. (Midjourney AI Image Creator)

Disclaimer: All products mentioned in this article were purchased by myself. I did not receive free samples, evaluation models, or other compensation from any manufacturer or retailer. I have no formal relationship with any manufacturer or retailer mentioned in this article - I have only been an arms-length customer. All brand names and product names used in this review are the trade names, service marks, trademarks, or registered trademarks of their respective owners. Further, this article reflects my unique circumstances and subjective opinions with regard to performance and other characteristics of the products discussed. Your mileage may vary.

    As I said at the close of the first Zombie Apocalypse Movie Theater (ZAMT) article: "The equipment described above is just a snapshot of my current equipment configuration. I expect that equipment mix to continue to evolve." That equipment mix has evolved, and I have shifted my focus to trying to simplify the setup of a portable theater for austere environments.

    My research has continued, including looking at several more projectors, and looking at utilizing Bluetooth speaker systems with built-in amplifiers to achieve a wireless or nearly wireless movie theater setup.

Cheap Projectors

    I continued to look at cheap projectors just to see what the minimum capabilities might be. Besides the ultra cheap (YG300, 360x240 resolution) twenty dollar projectors (sometimes over $50 on Amazon), I looked at other projectors that were around thirty-five dollars each.

    Only one of the cheap projectors, the Besus "J19 Mini Projector" with 480x360 resolution did not disappoint me. The slightly higher native resolution made a big difference in perceived picture quality. With a vertical resolution of 360 pixels (360P), the picture didn't seem pixelated like it does on lower resolution projectors. The 360P specification will become important later in this article.

    Overall, my opinion about cheap projectors remains unchanged: avoid the cheap projectors. Their quality seems spotty, and even when they work properly, they have very limited performance.

Anker Nebula Mars 3 (left), ETOE D2 EVO (center), and
Kodak LUMA 75 (right) projectors. 12 ounce soft drink can for scale.

Anker Nebula Mars 3 Projector

    The Anker Nebula Mars 3 projector is my current best projector. It is a 1000 ANSI lumen DLP portable HD (1920x1080 native resolution) projector. It has a fairly large 185 Wh built-in battery, allowing it to run for several hours on battery power. It has built-in speakers driven by a claimed 40 watt amplifier.

    The Mars 3 runs Android and has WiFi and limited Bluetooth connectivity. It can operate as a Bluetooth speaker (e.g. paired with your smart phone to play music), but it cannot use Bluetooth to transmit audio to a separate Bluetooth speaker.

    In my very brief light measurement session, I did not obtained an ANSI lumen number I trusted. The projector was so bright, there was significant light reflection off various room surfaces that biased up the light measurements I was taking. But, I have no doubt it outputs 1000 ANSI lumens in its brightest operating mode.

    The Mars 3 is fairly large (6.3 x 10.2 x 9.8 inches), with its smallest dimension being 6.3 inches. I wanted a hard case to protect it, but it is too thick to fit in any of the inexpensive Chinese hard cases, so I ended up spending a fair amount of money on a genuine Pelican case. (For a lot less money, I probably could have purchased a large surplus ammo can and lined it with foam rubber to protect the Mars 3.)

    I am annoyed that the Mars 3 cannot use Bluetooth to connect to external speakers.

Kodak LUMA 75 DLP Projector

    I purchased this projector as more of a novelty - an almost shirt-pocket sized projector. It is a 57 ANSI Lumen (my measurement) portable projector with a native resolution of 640x360 (360P). It measures 3.5 x 3.5 x 0.9 inches in size. It has a built-in battery that is claimed to operate the projector for two hours. It has one small speaker, driven by a claimed 1.5 Watt amplifier. The projector is charged using a 5 VDC USB-C cable, and can operate from an external USB power source. It did not come with a remote control.

    Due to its size, the LUMA 75, is a very basic projector. Navigation of its simple user interface and volume adjustment is accomplished via five touch buttons on the top surface of the projector. Focus is adjusted using a thumb wheel on the side of the projector. There is no keystone adjustment. It can play video via an HDMI cable, or play movies stored on a USB flash drive.

    The LUMA 75 does handle various aspect ratios I have tested (4:3, 16:9, 2.35:1) properly.

    With only 57 lumens of light output, maximum usable screen size will be limited. An online calculator that calculates screen brightness based on screen size and projector light output recommends a screen size no larger than 36 inches diagonal for acceptable brightness (15 foot-Lamberts) in a completely dark room. I was personally testing the projector with a diagonal screen size of 48 inches (8.3 foot-Lamberts), and thought it was acceptably bright.

    For its diminutive size, I really like this projector.

ETOE D2 EVO Projector

    I have been interested in a "sealed light engine" LCD projector, which is claimed to be dust proof, since learning such a thing existed. But, their prices typically start at around $150. I found the ETOE D2 EVO projector on TEMU for $84 - apparently, a clearance price. (The updated ETOE D2 EVO Pro is available on Amazon for more than I think it is worth)

    It is fairly compact with dimensions of 4.45 x 5.31 x 5.83 inches, and weighs a modest 3.6 pounds. The D2 EVO runs Android and has WiFi and Bluetooth connectivity.

    It has a claimed 400 ANSI lumen output, but I measured more like 157 ANSI lumens. Even with the light output being less than half what the manufacturer claims, it seemed fairly bright for such a compact transmissive LCD projector.

    Especially for the price, I really like this little projector. It has a bright sharp (after focusing) image, with the corners being less soft than I've seen before in transmissive LCD projectors. I like the dust proof "sealed light engine", which could be a very important feature in a post-apocalyptic scenario were filtered clean indoor air may no longer be common.

    One downside of this projector, which I am seeing on a lot of other projectors, is that the projector itself only has a power button. It is unusable without its remote control.

Monster X6 (left), ECOXGEAR Boulder Max Pro (right), and
Zealot S49 (bottom center) Bluetooth speakers. 12 ounce soft drink can for scale.

Bluetooth Speakers

    Sometime after I finished the first ZAMT article, I started looking at portable amplified speakers to reduce setup complexity. Again, like everything else, manufacturer specifications are exaggerated.

    The Bluetooth amplified speakers I have looked at are monophonic - they take the stereo signal, combine it into a single audio channel, and amplify that signal. Of course, you can always directly plug an audio cable into the speaker to use it as a standard amplified speaker, but that kind of defeats the purpose of having Bluetooth speakers. There are Bluetooth speakers that can be set up to be left or right channel for stereo sound, but I have not experimented with any of those speakers.

    I first experimented with some inexpensive Bluetooth speakers (Zealot S49) that were only a little bigger than a soft drink can. The manufacturer claimed these speakers had 20 watts output, but I seriously doubt it - a half watt is probably closer to the truth. They sounded muddy and were not as loud as I hoped.

Monster X6 Speakers

    I was first exposed to the Monster X6 speakers at my employer's "all hands" meeting held in a large warehouse-like building. But for the horrible acoustics (echo, combined with the speakers sitting on the floor), they would have been adequate for the room that was seating several hundred people.

    A couple weeks later, I saw the Monster X6 speakers on sale at Sam's Club. They are a PA and Bluetooth "Party Speaker". I bought a pair and brought them home. They claimed to output up to 600 watts. They have Bluetooth in addition to an amazing number of wired connectivity options. They require 120 VAC. Each speaker came with a tripod stand and an inexpensive microphone. These speakers also have a pair of wheels and an extendable handle so they can be pulled like a rolling suit case.

    What makes them a "Party Speaker" is that they have a bunch of LEDs on the sides of the front grill and around the woofer that will light and change color to the music being played - cute for a party, but annoying in a theater environment.

    In testing, I overheated them - but fortunately didn't kill them. Just before I shut them down because I was smelling something overheating, the pair were drawing 150 watts - 75 watts for each speaker. No, they were not 600 watt speakers, although they were really loud (I was wearing the hearing protection I would wear when shooting at an indoor range).

    The Monster X6 speakers are really big (27.5 x 20.5 x 12.0 inches, 38.8 lbs. not including the stand), so I started looking for smaller Bluetooth speakers, but not too small.

ECOXGEAR Boulder Max Pro Speakers

    Again at Sam's Club, I came across ECOXGEAR Boulder Max Pro speakers on sale. While they are still large-ish, they are much smaller (15.5 x 11.4 x 19.8 inches, 30.8 lbs.) than the Monster speakers. The ECOXGEAR speakers are Bluetooth "party" speakers, they are IP67 waterproof (their marketing videos show the speakers floating down a stream), and they are battery powered (7 AH 13.8 volt lead-acid rechargeable). All external jacks (120 VAC, audio-in, microphone, USB) are behind fairly substantial waterproof covers. 120 VAC is required to recharge the built-in battery, and of course, the speakers can run off 120 VAC. The manufacturer claims they output up to 100 watts - I doubt it. These speakers also have a pair of wheels and an extendable handle.

Wireless Speaker Latency

    Audio latency between the projector and wireless Bluetooth connected speakers turned out to be a much bigger problem than anticipated. Audio latency is observed as audio and visual events (e.g. speaking lip movement, sharp noises) in the movie not being synchronized.

    I expected to observe some Bluetooth speaker latency, but it was more noticeable than expected. I observed an estimated latency of around 200 milliseconds (one-fifth of a second). This 200 ms latency observation is consistent with what I expected from my reading on the subject.

    Then I had a bright idea to try using a small analog FM transmitter. These FM transmitters used to be very common in the era where most vehicles only had an AM/FM radio, and there was no other way to connect an audio source (e.g. MP3 player) to the vehicle's audio system. The FM transmitter plugs into the earphone jack of the audio source and transmits a weak short range signal that can be picked up by a nearby FM radio.

    The FM transmitter worked beautifully (no audio latency) when I was picking up its signal using an analog FM radio. However, when I used the built-in FM receiver of the party speakers, I observed a latency of 480 milliseconds (almost one-half of a second) - this was completely unexpected and completely unacceptable.

    Some projectors have audio latency adjustments, but I have not seen that capability on the low cost projectors. The Mars 3 projector, which lacks Bluetooth transmit capability, has a latency adjustment - up to 250 milliseconds.

Dealing With Audio Latency

    There are several ways of dealing with the audio latency:

    (1) Ignore it. Much of the time, the 200 ms Bluetooth latency shouldn't be a serious distraction.

    (2) Try to adjust it out or minimize it if the projector has a latency adjustment.

    (3) Run an audio cable from the audio output (headphone jack) of the projector to the amplified speaker or speakers. (This still reduces complexity over using a separate audio amplifier as I did in the first ZAMT article.)

    (4) Use analog FM radios to receive the audio from the FM transmitter, then connect those radios, via their headphone jack, to the amplified speakers. But, this increases setup complexity.

    The analog FM transmitter I experimented with was the Scosche FMT7-SP1 FM transmitter, which was around ten dollars. It is fairly small, powered by two AAA cells, with an attached six-inch cable with a 3.5 mm stereo plug to be plugged into a headphone jack. To get acceptable performance, this analog FM transmitter must be coupled with an analog FM receiver to eliminate latency.

    (5) Use a special purpose low-latency Bluetooth wireless audio transmitter/receiver set. These require a short cable for the required 5 VDC power, and a short cable for audio. This option has simpler setup than using analog FM radios, since no tuning of radios is required.

    I purchased a special purpose low-latency Bluetooth wireless audio transmitter/receiver set that had a claimed 20 millisecond latency. In practice, the latency was imperceptible. The receivers can be powered from the USB port built into the speakers. The transmitter can similarly be powered by the projector if you have a spare USB port.

Media Player

    The media player discussion of my first ZAMT article still applies. DVD and Blu-ray disc players, USB flash drives loaded with movies, along with any other video source you might have available are all valid options.

    I've noticed that with the NEBULA Mars 3, Kodak LUMA 75, and ETOE D2 EVO, a composite video input has been omitted. However, inexpensive composite-to-HDMI video converters are available if needed, and they work fairly well. These converters need 5 VDC, and the projector's USB plug can provide the necessary power for the converter. These converters tend to run a bit warm, which may reduce operational life - they are cheap, get two.

Almost Completely Wireless Theater

    With a battery powered projector (with a short patch cord to a Bluetooth transmitter), battery powered Bluetooth speakers, and movies loaded on a USB flash drive, it is possible to have an almost completely wireless improvised movie theater.

    Of course, I could always rely on the built-in speakers of the battery powered Mars 3 or battery powered Kodak LUMA 75 with movies stored on a USB flash drive to be completely wireless.

    In most scenarios, electrical power, even if provided by a power station, will still be needed to run the major components. Battery powered Blu-ray players are rare and expensive, so a Blu-ray player will most likely be powered by 120 VAC. Further, having a battery powered projector and speakers does not obviate the need for a reliable power source - those battery powered components will need to be recharged after use.

Conclusion

    Even before a zombie apocalypse, there are many circumstances where a semi-portable movie theater that can operate "off grid" would be desirable.

    I set out to assemble an entirely wireless movie theater, but quickly discovered that being entirely wireless was impractical. Bluetooth audio latency turned out to be a worse problem than expected, so I explored several alternatives to minimize audio latency while also minimizing setup complexity.

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Resources:

• This YouTuber provides good reviews of video projectors. He uses uses test equipment to objectively measure performance characteristics of the projectors being reviewed. His focus is the home theater, but he also reviews portable video projectors.
• This article explains why projector lumen output matters, and provides recommended lumen output ranges for various environments. I personally think their recommendations, based on my own observations with my equipment being used in a dark room, are a little high. But, their recommendations provide a starting point in analyzing needs.