BenQ TH685i 4 1 1080P DLP Projector
  • Performance
  • 4
  • Features
  • Ease of Use
  • Value
  • Excellent 16.4ms input lag at 60Hz and 8.3ms at 120Hz
  • Uses the Android TV OS for streaming
  • Good color accuracy for the price
  • Average contrast ratio
  • Netflix not available from the Google Play Store
Our Take

The BenQ TH685i is a solid gaming projector that, thanks to the included BenQ QS01 streaming stick, works well as a living room display for TV and movies, too.

BenQ TH685i rightfacing

There's been a big to-do over the past few months about the release of new consoles from Microsoft and Sony—the Xbox Series X/S and PS5, respectively—and next generation gaming at 4K with 120Hz refresh rate. And while that is all very exciting (if you're into it), the reality is many gamers are perfectly content to continue at 1080p on those consoles, or with their Xbox Ones and PS4s considering how difficult it is to snag one of the new ones.

That isn't to say that any projector will do. One of the biggest gaming hurdles projectors still deal with is input lag—the amount of time it takes a button press on a controller to cause a reaction on screen. If that length of time is too high, it could lead to frustration completing jumping puzzles or getting consistently defeated by enemies and other players. To compete with a TV, that number needs to be below 20ms at least. The $899 BenQ TH685i meets and exceeds that with ease, especially with games played at 120Hz. And while being mated with a gaming console is the TH685i's bread and butter, BenQ includes an Android TV streaming stick for TV and movie streaming when the gaming sessions are over.


As noted, low input lag is of utmost importance for gaming on a projector. Projectors in general are notorious for having lag that can top 100ms, which would cause a game's response to feel sluggish or that your reflexes are slow. For most gaming, I recommend finding something that is at least below 35ms, and if possible below 20ms (especially if you'll be playing against another player). The game picture mode on the BenQ TH685i turns on the projector's Fast Mode, which disables image correction and enhancements like keystone correction and shortens the time it takes to display the image by using an algorithm, therefore leading to a lower input lag. Fast Mode can be enabled in the other picture modes as well—although the Fast Mode option is off and grayed out with HDR. In Game mode, the TH685i has an input lag of only 16.4ms. Even outside of Game mode the projector's input lag measured only 33.1ms, still an impressive number for a projector and something many casual gamers wouldn't even feel. BenQ's literature states the TH685i can achieve 8.3ms of lag at 120Hz—a completely believable statement considering it's already measuring 16.4ms at 60Hz. The projector changes its refresh rate when a 120Hz signal is detected from a console or PC. (120Hz support wasn't turned on with early firmware versions, so be sure your projector's firmware is fully up to date.)

The TH685i is a single-chip DLP projector that has a 6-segment (RGBWYC) color wheel. It has a native resolution of 1080p (1920x1080), although it accepts 4K (3840x2160) and downconverts the signal. And in the sub-$1,000 projector world that's becoming increasingly overtaken by LED and laser projection technologies, the TH685i uses a conventional lamp as a light source with a claimed light output of 3,500 ANSI lumens (although we measured lower on our sample). The lamp will last up to 15,000 hours in LampSave mode, which adjusts the power automatically based on the brightness of the content to elongate the lamp's life. Lamp life in Eco mode (which lowers the brightness overall) is up to 10,000 hours, in SmartEco mode (adjusting light based on content's brightness with a focus on image quality) it's 8,000 hours, and in Normal lamp life expectancy is 4,000 hours.

BenQ TH685i front

While on the subject of light output, BenQ includes a feature called LumiExpert. It adjusts gamma based on the ambient light and when on, there's a five-position slider to adjust it. I generally eschew features that sense and adjust image quality based on ambient light like LumiExpert, but in the case of the TH685i it was able to help the contrast and allow for better shadow detail. Projectors at this price are not known for their contrast, so a feature that works to improve that performance is a welcome touch.

Cosmetically, the TH685i almost identical to the TH685 released March 2020. Its white case is 4 x 12 x 9 inches (HWD) and weighs only 6.2 pounds. On top there are rings to manually adjust the 1.3x zoom and focus. They can both be a bit fiddly to get right—the focus more so than the zoom, which has a tab on it that can be guided more easily with a finger. With a throw ratio of 1.13-1.46, the TH685i needs 8 feet 3 inches to projector a 100-inch image (check out the ProjectorCentral BenQ TH685i Projection Calculator to see if it would fit in your space and screen size). Also on the top are menu navigation buttons and LED indicator lights.

The only cosmetic difference between the TH685 and TH685i is the collection and orientation of inputs on the back of the projector. Instead of both of the HDMI 2.0 (with HDCP 2.2) ports situated next to one another and directed straight out of the back as is found on almost every projector, one has been moved behind a plastic cover (along with a mini USB power connector) and dedicated as the media streaming port for the included QS01 HDMI dongle. Once plugged in, the dongle lays flat against the back of the projector and can be protected and hidden by the plastic cover. This media streaming bay is meant specifically for the QS01 dongle and not for a different streaming stick (although you could feasibly put one in the other HDMI port and power it from the USB Type A on the back).

Other minor changes from the TH685 to the TH685i include the removing of the monitor-out D-sub connector—a PC VGA D-sub input is still there—and the moving of the 3.5mm audio in/out ports from the back left to the back right. Speaking of audio, the HDMI port not dedicated to the streaming dongle is equipped with Audio Return Channel, which should feed audio from the dongle back to an AV receiver to which your other sources (game console, cable box) can be connected. But if you need that HDMI port for a source component that can't feed audio separately to an outboard system, you'll need to use the analog audio out. There's no optical digital output to use as an alternative.

The QS01 streaming stick provides the Android OS for the BenQ TH685i, and it is a welcome change from the Aptoide OS many projectors of this price range have used till now for their streaming OS. Guided setup goes through connecting to a wireless network, signing into a Google account, and installing from a list of popular apps. If you've used Android TV elsewhere, previously used settings and search preferences can be accessed by linking a Google account, but it isn't necessary for projector operation. Navigation through the OS home page is pretty intuitive, although I find the Google Play Store to be confusing in its movie and TV show layout. The home page is organized with rows for each app and a selection of shows for each. At times it can be a little sluggish, but overall it's a decent interface. Chromecast is also supported if you want to stream something from a mobile device. What isn't available through the Android TV OS is Netflix. Instead it would need to be cast from a computer or mobile device (BenQ is in discussions with Netflix for compatibility, so we might see it added down the line).

The non-backlit white remote has a microphone for using Google Assistant, menu navigation and settings adjustment buttons (such as keystone), two dedicated app buttons—one for Amazon Prime Video and one for FamiLand, a BenQ app with curated content for kids age 6 and under. There are two buttons to access the Android TV settings or the projector settings, and even though the one for the projector settings is clearly marked "Projector Menu," I habitually pressed the button with the gear on it that opened up the Android TV settings.

Key Features

  • 1920x1080 (1080p) native resolution
  • Accepts 4K
  • 3,500 ANSI lumens brightness
  • 120Hz refresh rate
  • 8.3ms input lag at 1080p/120Hz
  • Up to 15,000 hours lamp life in LampSave mode
  • HDR10 and HLG support
  • BenQ LumiExpert for contrast enhancement
  • Included QS01 streaming stick for Android TV OS with Google Assistant
  • 1.3x manual zoom
  • 3D capable
  • 95% of Rec.709 color gamut


BenQ TH685i front top

Display Modes. The BenQ TH685i has seven different SDR picture modes—Bright, Living Room (which is its default), Cinema, Sports, Game, User 1, and User 2. There are modes for HDR10, HLG, and 3D that are automatically switched to when the appropriate signal is detected. Bright is the brightest of the picture modes. It put out the same 2,705 ANSI lumens in our measurements after multiple readings, or 77% of the published spec, which BenQ says falls below any expected tolerance and might suggest an issue with our sample or lamp. That mode also exhibits the green tint we've come to expect from most projector's brightest picture mode. It isn't as egregious as others I've seen and would be acceptable to many viewers for non-critical viewing in ambient light. Cinema, the most color accurate of the picture modes, has 59% of the light output of Bright. It's more than enough for most situations, but still benefits from turning off extra lights if possible. The other modes all lean a bit blue in color temperature, but were also still acceptable for use.

Using Calman calibration software from Portrait Displays, an X-rite i1 Pro 3 spectrophotometer, and a Murideo Six-G pattern generator, Cinema mode out-of-the-box measured the best color temperature (Normal) just above the 6500K target, at 6697K. Red and green were both a little undersaturated, cyan was too blue, and the dark to midtone grays were a bit too bright (this affected the overall contrast of the picture). The TH685i measured 94.4% coverage of the Rec.709, just off the published 95% spec but well within a margin of error. BenQ's LumiExpert, by sensing ambient light and adjusting the gamma, helps to add a bit of depth to the image. I only used it during the day and tended to use the 1 setting on the five-point slider (-2 to 2). The out-of-the-box measurements were done with Brilliant Color set to 10 (its default), which boosts white brightness but decreases color accuracy. Turning down Brilliant Color improves color accuracy, but affects the color temperature a little (making it warmer in this case), and decreasing brightness. I found a good compromise to be a setting of around 6, which improved colors to my eye and decreased brightness by about 25% (still enough for my room).

There are full CMS calibration controls for RGBCMY, and gain and bias (offset) for white balance. Gain and bias calibration allowed me to improve the overall grayscale, but there were still some inaccuracies in the midtones due to elevated luminance. Color too was able to be improved through calibration, although green and red were always still slightly undersaturated. But these measurements and observations are not meant to suggest either excessive or noticeable color inaccuracy that most viewers would detect, and are not necessarily unexpected in a budget projector that's designed to be used for gaming and binge-watching in moderate ambient light.

SDR Viewing. I've finally begun to catch up on one of my favorite shows of the past decade, The Expanse. Season 5 was released on Amazon Prime Video at the end of 2020 and is based on my favorite book of the series. And it doesn't disappoint. The TH685i does a good job downconverting the 4K version, showing off the detail of the floating ship displays and skin texture of the actors well. All skin tones looked natural and the explosions as Tycho station is infiltrated are brilliant. The one place the BenQ falters a bit is in the darkness. LumiExpert can help add some dimension to shadow detail when there's ambient light, but in a darkened room the heightened black level robs some depth to the shots of deep space.

Expanse S5
Even though it's downcoverted, the BenQ TH685i retains great detail in 4K material such as season 5 of The Expanse. (Photo Credit: Amazon Studios)

When Jack Skellington sings of the color everywhere in the song "What's This?" from A Nightmare Before Christmas the TH685i obliged. The undersaturated red and green that came out in the measurements were of no concern. They looked nice and vibrant in the candy cane red and Christmas tree greens in Christmas Town.

As with any single-chip DLP with a color wheel, there's the chance of rainbows. I am not very susceptible to the phenomenon, although I have seen them in the past, and didn't experience any issues with them on the TH685i. If they are something you've dealt with in the past, it's always best to try and look at one before buying or find a retailer with a good return policy.

HDR Viewing. The new UHD release of The Lord of the Rings trilogy is absolutely brilliant and rekindled my love of the series (although to be honest, it hadn't diminished much since its initial theatrical release). The detail on the discs is stunning and the TH685i is able to show off the ripples in the Bruinen river outside Riverdell as Arwen flees the Nazgûl with Frodo. The wooden architecture of Rivendell has nice depth thanks to the variety of whites and browns.

There's a five-position HDR Brightness slider (ranging from -2 to 2) that adjusts overall highlights. I found the extremes both adversely affected the image—a setting of 2 pushed whites too much and caused colors to look unnatural, while -2 caused dark details to disappear. I settled on 1 for almost all of my viewing. It gave some nice pop to the outdoors and the rocky walls in the depths of Moria kept their texture.

Gaming. The input lag is practically nonexistent on the BenQ TH685i and makes flying an X-wing in Star Wars Squadrons on my Xbox Series X feel very smooth. Laser fire was immediate and there was never any evidence of screen tearing. The game is a fantastic homage to the X-wing games of the '90s while still being its own experience. There are some beautiful and colorful nebulas in the background of space that pop out, especially when a sun shines from the center of them.

SW Squadrons X wingstill
The low input lag of the BenQ TH685i means there's no perceptible delay from pressing the controller's button to firing at an incoming TIE Fighter. (Photo Credit: EA Games)

Even when playing a game at 60Hz, such as Spider-Man: Miles Morales, the TH685i's response feels quick. Webs shot out from my wrists with no delay and swinging through the air is smooth. Any night time exploration means the curtains need to close, though. As with movies and TV, it can be hard to see into the shadows with ambient light around.

3D Viewing. The BenQ TH685i had no issue picking up a 3D signal from my LG BD player. I wasn't able to set it to Auto, but the projector correctly set it to frame packing 3D mode when watching Ant-Man. During the fight scene between Ant-Man and Yellowjacket in the briefcase, there was good depth to the image with only a slight bit of blur on fast motion. It didn't take away from the action at all. The light output of the TH685i was more than enough, even with a little bit of ambient daylight—although too much ambient light caused shadow detail to be lost as the scene continued through the evening suburbs.


The BenQ TH685i offers a lot of what gamers look for, and it delivers. The input lag in game mode is some of the lowest you'll find on a projector, especially with 120Hz refresh rate. Color accuracy is very good for a projector under $1,000. And the addition of the Android TV interface instead of something like Aptoide makes it a viable option for TV and movies—even if it's currently missing direct support for Netflix. The contrast—while okay for the projector's price range—is still average at best, which could leave enthusiasts wanting for more. But for a gaming projector that can serve well for movie nights and holds up to ambient light during the day, the BenQ TH685i is solid.


Brightness. The brightest mode available on the BenQ TH685i is Bright with the lamp in its Normal setting and the zoom lens set to its widest position. It measured 2,705 ANSI lumens on our sample, which is just over 77% of the published spec of 3,500 ANSI lumens. BenQ says this is below the expected range of tolerance and may suggest an issue with our sample. In Cinema picture mode, the brightness on our sample drops by 59% to 1,585 lumens. There are three additional lamp modes—Economic, SmartEco, and LampSave. In Bright mode, Economic lowered the overall brightness by 32.3% to 1,830 lumens. SmartEco adjusts the light output based on the content's brightness with a focus on image quality and with the measurement of a full white screen didn't affect overall brightness at all. LampSave mode, which adjusts the power automatically based on the brightness of the content to elongate the lamp's life, lowered brightness by 25.9% to 2,003 lumens.

Color brightness was measured in Bright picture mode with Brilliant Color set to 10. This resulted in a color brightness measurement of 28% of white. As Brilliant Color is lowered, and therefore the white brightness comes down, the color brightness percentage improves. For example, at Brilliant Color 7 the color brightness is 33%, 46% at Brilliant Color 4, and 92% at Brilliant Color 0.

The measured brightness of display modes is as follows:

BenQ TH685i ANSI Lumens

Mode Normal Economic SmartEco LampSave
Bright 2,705 1,830 2,705 2,003
Living Room 1,471 996 1,471 1,090
Cinema 1,585 1,073 1,585 1,174
Sports 1,589 1,076 1,589 1,177
Game 1,467 993 1,467 1,087
User 1 1,467 993 1,467 1,087
User 2 1,471 996 1,471 1,090
HDR10 1,560 1,056 1,560 1,156

Zoom Lens Light Loss. Changing the zoom from its widest position to its maximum telephoto position resulted in a 13.2% loss of light.

Brightness Uniformity. Brightness uniformity measured at 87.1% at its widest zoom and 83.2% at its longest zoom. In both positions there was no visible hotspotting with any content.

Fan Noise. Under lab testing in a soundproof room using the industry-standard multi-point averaged methodology, BenQ measured and rated the fan noise at 35 dBA in Normal lamp mode and 29 dBA in Economic. In a single-point measurement at a distance of around three feet directly below the ceiling-mounted projector in my living room (which has a noise floor of 31.7 dBA), I measured 40 dBA in Normal lamp mode. There is also a high altitude setting and when turned on, the fan noise and an accompanying whine steadily increased up to 51 dBA over about one minute. When turned off, the noise slowly ramped back down. Note that ProjectorCentral's casual real-world noise measurements always come out higher than the factory spec.

Input Lag. With a Leo Bodnar lag tester outside of game mode I measured a 1080p/60Hz lag of 33.1ms. Fast mode lowers that to 16.4ms when turned on. Both values are excellent, but with fast mode the input lag rivals that of TVs. With a 120Hz signal, BenQ lists the input lag as 8.3ms.


BenQ TH685i connections
  • HDMI 2.0 with HDCP 2.2 (x2, one for the QS01 media player)
  • USB Type A
  • PC D-sub in
  • 3.5mm audio in
  • 3.5mm audio out
  • RS-232

For more detailed specifications and connections, check out our BenQ TH685i projector page.

To buy this projector, use Where to Buy online, or get a price quote by email direct from Projector Central authorized dealers using our E-Z Quote tool.

Comments (1) Post a Comment
John Posted Apr 23, 2021 9:36 PM PST
Since this is a gaming projector review, you really need to quote input lag figures for HDR. Anyone using a PS5 or XBox Series X will almost always these days be gaming in HDR. Additionally, given the large screen size projectors afford; I don't know anyone who'd want to play Destiny 2 say in 1080p. I tried that and it looked so weak compared to 4K resolution. Except for a few stragglers, 1080p really is dead now for mainstream gamers, projectors just don't seem to be keeping up with TVs in this regard.

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