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Optoma HD91+ DLP LED Projector Review

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by Phil Hinton Oct 30, 2015 at 8:10 AM

  • Home AV review


    Optoma HD91+ DLP LED Projector Review
    SRP: £2,999.00

    What is the Optoma HD91+?

    The Optoma HD91+ LED DLP projector is an updated version of the HD91 that Steve Withers reviewed back in January 2014. The plus model is an interesting concept within both the automotive and home electronics markets and usually allows a product to enjoy an extended life cycle. This is normally achieved by slightly upping performance levels and perhaps adding a new feature here and there, without huge development costs or cosmetic changes. That is certainly the case here with the HD91+ as it looks identical to the older model with no obvious signs of improved performance; well apart from the red go faster stripe around the lens!

    The original HD91 caused quite a storm when it hit the market 18 months ago with the use of an LED light source. The single chip 1080p model also carried a price tag that was unheard of until then for an LED projector at only £2,999. The LED home cinema projector market up to that point had seen eye watering price tags starting at £12,000 and going all the way up to £19,000. So eye brows were certainly raised when the Optoma came along at such an affordable price point for enthusiasts and consumers. With the new ‘plus’ model now released to extend the life cycle of the technology – is it one last fling for LED DLP before Ultra HD and lasers become more of a must have? Lets find out.

    Design and Connections

    The HD91+ is identical in every respect to the normal HD91 model when it comes to the chassis and design. Build quality is good although the body does feel ‘plastic’ but the wavy design of the case is a step up on some of the more budget square box looks out there. The front of the projector is dominated by the large lens which is centrally mounted. This has manual zoom and focus rings which have a good feel and hold settings well. However being manual means that if you are using a scope screen there is no auto lens memory functionality, you have to do it by hand. There is also a basic lens shift function with the adjustment wheels under the lens housing at the front of the unit. At the bottom of the chassis are four adjustable feet to help with levelling the unit when table mounted. The HD91+ can also be ceiling mounted if desired. There are no menu controls on the projector at all, so make sure you don’t lose the remote control. The rest of the body is made up of vents and exhausts to both of the sides to allow airflow and as this is an LED unit, cooling and consistent temperature is important.

    The HD91+ is 3D capable, but as with all manufacturers these days, it doesn’t come with the emitter or glasses which need to be purchased separately. There is no emitter built into the projector.
    Optoma HD91+ Design and Connections
    Optoma HD91+ Design and Connections

    At the rear of the HD91+ we have a generous line-up of inputs and connections. We have two HDMI inputs, a VGA input along with composite and component inputs. There are two 12v triggers and an RS232 control port along with two USB inputs for software updates and powering other devices. There is a power socket to the bottom left when looking at the projector from the rear on a table. The last connector is for the optional 3D emitter which is not included as standard.

    Finally we have the remote control which is a small plastic affair that sits well in the hand and usefully has a backlight. The directional and OK keys are the most used and as such they take up the entire central position of the remote. Above these are direct access keys for picture adjustments such as gamma and to the bottom are the aspect ratio keys, 3D and Pure engine, and below these are the source input keys. The remote has a reasonable weight which allows easy access to the keys when held and the backlight is a must have in dedicated cinema room.

    Out-of-the-Box Settings

    The best measured out-of-the-box settings for the HD91+ were found in the Reference display mode, with Colour Temperature set to D65, Colour Gamut at HDTV, Gamma at 2.3 and LED brightness at 100%. There are ISF options in the menu under display mode, but these are locked for normal users. We switched off the dynamic black 1/2/3 features as they introduced visible brightness adjustment and they also messed about with the gamma on the fly, adding noticeable effects to the image that are not desirable if you want accuracy to any standards. We also switched off the Pure engine selections which add additional sharpening and ringing to images using UltraDetail, motion interpolation with the PureMotion setting and over saturated colours with PureColor. These options are switched off so we can achieve an image that gets as close as possible to what is intended to be seen by the TV and movie producers. You can of course experiment with these options to find something that might suit you personally, especially when it comes to certain content like live sports. Below are our measured results for the settings above.
    Optoma HD91+ Out-of-the-Box Settings
    Optoma HD91+ Out-of-the-Box Settings

    Starting with the greyscale and we get a reasonable result with errors mainly in the brighter areas of the image where blue and red are high and there is a lack of green. Gamma is also tracking around 2.2 but with a dip in the lower black area of the image, probably an attempt to make low level detail stand out; a weak point of DLP images. Actual viewing of normal film material doesn’t show up any major issues with just the hint of a reddish tint to the lighter areas of the image.

    The colour gamut result is also reasonable for an out-of-the-box preset with errors in luminance and hue for green and magenta, and other slight issues for the remaining primary and secondary points. However, once again with actual viewing material the vast majority of viewers wouldn’t pick up on any obvious issues. As an out-of-the-box setting both the greyscale and colour gamut would be quite adequate for the majority of viewers without causing any major issues, but there is scope to improve the image quality in terms of the greyscale and colour gamut, and we have the calibration controls available to allow that.

    Calibrated Settings

    Thankfully the HD91+ has a good line-up of calibration controls that work correctly and should help us dial-in a reference picture in terms of colour and greyscale.
    Optoma HD91+ Calibrated Settings
    Optoma HD91+ Calibrated Settings

    And that certainly is the case with both. Looking at the greyscale first we used the two point correction and within a couple of clicks we had a perfect track with DeltaE errors all under 2 which is below the threshold of being visible. The controls were not as fine as some we have used recently, so it was a little trickier to be more precise, but as errors are already so low, that is not an issue. Only gamma let the side down and nothing we tried could tame the dip at 10ire, but it doesn’t interfere too much with the final image on screen, so nothing to get worried about.

    The colour gamut was also easy to correct using the superb Colour Management System (CMS). We used a wider gamut than HDTV and then brought back each point and made sure luminance was correct – probably the most important element of using such a control. We also checked the tracking from 25, 50 and 75% saturation points for all three primary and secondary colours. Only red and blue had any real issues with slight undersaturation at all points to 100%. Overall we were very happy with the results here which given the colour wheel issues of lower priced single chip DLP machines, was as accurate as you can get at this price point for the technology.

    Picture Quality

    Optoma HD91+ Picture Quality

    Out-of-the-Box Performance

    Being an LED DLP projector and having seen what Steve made of the original model in his review from 2014, it was interesting to note that the two major upgrades for this ‘plus’ model is a higher brightness of 1300 lumens claimed and 600,000:1 on/off contrast figures. All the other specs are the same between the models, so how bright is the HD91+? Compared to our resident JVC DLA-X700 which has 100 hours on the clock and the HD91+ with 40 odd hours, the brightness from the same distance (15ft) onto a 110” scope 4K Enlighter screen was almost identical at 800 lumens with calibrated modes. Of course the beauty of the HD91+ against the JVC is that the LED brightness will remain consistent for far longer than the JVC’s bulb. The obvious downside to the LED based light engine is the fact it has to be kept at a constant temperature which requires good air circulation and ventilation and this introduces noise.

    In our review room the projectors are mounted on a large stand just above and behind the viewing position and here we measured 26db from the HD91+. Ceiling mounting might help in that regard but there are actually two distinct noises and different frequencies here. You have the low pitched noise of a fan as you normally expect to hear, but also a high pitched electrical sound of the LEDs which changes pitch as you adjust the LED brightness level in the menus. As 100% brightness is required for most installations that might mean the pitch is annoying if you pick it up. Again we come back to the fact that there are no perfect displays and there are trade-offs that have to be made to achieve something new like LED technology at this price point.

    We tested the HD91+ in our usual bat cave cinema room and for the most part it produced an impressive image taking into account the DLP technology being used. So let’s start with the not so good first and get it out of the way. DLP technology is not great at producing deep, rich black levels with just above black shadow detailing. It is the weakest point of the technology and that is the case here with the HD91+ and in a bat cave it is very noticeable. Even with DynamicBlack enhancer switched on, the blacks were meagre with no subtle shadow detailing. Even using an ND filter will not improve matters and it’s the way the DLP technology works that causes the issues. However, if you have light coloured ceilings and walls in your viewing room this will already lift the light floor of your viewing room and as such it will mitigate the black performance somewhat. You will still miss out on the lower shadow details, but using a JVC in such a room would likely be similar and certainly even up the score a little. But if we are being completely honest here, there is no difference in the black performance here to that of a sub £1000 single chip DLP, so that’s something to bear in mind.

    Motion handling, brightness, great looking colours and sharpness are the big 'plus' points.

    Now the positives and that is definitely the sharpness of the lens being used here along with good strong colours and excellent motion handling. While the HD91+ can’t handle 2:2 (Pal) cadence, this is a minor point in what is an excellent display of video processing and image motion. Brightness was also very good in our testing environment and helped produce a fairly even uniform image on screen. We did notice a slight green tint, and we mean very slight and only seen on dim black images that was still there after calibration. We mention this to be complete in our assessment and there is nothing to suggest this is a flaw with all HD91+ projectors, it was slight enough for most to miss it and we only noticed with very specific material and when looking for it. Colours out-of-the-box were subtle enough not to cause any issues with skin tones and for the most part they were bright, detailed and fairly natural. Only now and again would there be an obvious issue with slightly inaccurate hues, especially with green, on some very well know test film sequences. There was no need to use the PureMotion feature as the motion with 24p film material was superb with fluid film like movement on show. The out-of-the-box performance was very good and most users would be fairly happy with the image on offer, but we could improve things a little more with a calibration.

    Calibrated Performance

    Blacks aside, there is nothing we can do to improve them and retain image fidelity, the rest of the image really benefits from an accurate calibration. Correct hues and well saturated colours just add back realism to well-known sequences and help with providing excellent skin tones. The flowing red hair and red cheeks of Victoria in the control room in Oblivion really stand out, without looking unnatural. The cyan cast of the scene mixed with the red tones of the actress and the gold of the sun reflecting behind her really stands out. The sharpness of the scene is helped with the excellent lens and focus ability of the HD91+ and is another strong point of DLP.

    The other advantages of DLP and LED are the lack of rainbow effect in most cases. It can still be seen by those most susceptible to seeing it, so if that’s you, perhaps a thorough demo with challenging scenes is a good idea before buying. But I am happy to report that I didn’t see any at all with the HD91+ and I occasionally do with other single chip DLPs with colour wheels. The other neat feature of LED is instant power down and power on. If you have owned any projector in the past or present, this takes some getting used to. And finally with a calibration on the HD91+ you should only have to retouch any settings every 50 to 100 hours if the claims of minimal light dimming and shift are to be believed (still early days with the technology but it is promising).

    Optoma HD91+ Video Review


    OUT OF


    • Good calibrated greyscale and colour gamut
    • Great motion handling
    • Good quality lens
    • Almost a lack of rainbow effect
    • Good build quality
    • Respectable out-of-the-box presets
    • LED shows promise for the future


    • Mediocre blacks
    • Lack of low end shadow detail
    • Noisy in operation
    • Manual lens shift, focus and zoom
    You own this Total 3
    You want this Total 0
    You had this Total 0

    Optoma HD91+ DLP LED Projector Review

    With the home entertainment market marching towards 4K Ultra HD resolution, HDR and wider colour spaces and UHD Blu-ray players and discs, do you still buy a 1080p DLP projector? Of course the answer to that question is entirely personal and there will be many who quite rightly flag up the issue of a lack of content to fulfil the UHD promise at the moment, so why the rush to upgrade? Then you have the fact that only one manufacturer so far has released native 4K UHD projectors in the consumer market and the price tags are still high to enter the game. Plus not all the new UHD projectors will have HDR or wider colour gamuts, so again, is it too early to jump from HD only?

    There is no such thing as the perfect display and you need to make compromises to find one that will ultimately suit you. The HD91+ could be seen as a cynical last throw of the dice for a consumer LED DLP projector with no obvious 4K UHD future yet drawn out for DLP as a whole in the market yet. With the standards yet to be finalised, the future is not overly clear for the technology. But LED is a statement of intent when it comes to the issue of bulb life and brightness drift. It offers instant on/off capabilities, long life claims and a consistent light output that far out-shines bulb based machines. In the HD91+ it is also bright enough for most average sized UK cinema (living) rooms and decent sized screens. LED also helps with consistent colour tones and holds on to calibrated settings longer than traditional bulb machines. Being DLP-based the motion handling and picture processing is also first class whether its upscaled DVD or Blu-ray you are watching and with a superb quality of lens fitted, the images are also pin sharp.

    The only real downside is an issue that plagued the HD91 first time around (and most other single chip DLP projectors) and that’s the mediocre black levels and non-existent low end shadow detail. No matter what you try there is no getting around this issue within a light controlled room. However, in a typical living room with white ceilings and walls there is already a lifted black level that the room will have and in such environments, with more ambient light and light hitting the screen, the blacks will appear less of an issue (there will still be no shadow detail though). So again, it will come down to compromises and matching the product to the environment to get the best out of it.

    The out-of-the-box performance could have been more accurate and we will feed that back to Optoma. Given LED doesn’t drift as much as a bulb, something like an accurate THX or Cinema mode on such a machine would be beneficial. Saying that, most users would be happy with the best settings out-of-the-box and if you decide to get it calibrated, you shouldn’t need to worry about it drifting as fast as a bulb-based projector. In calibrated settings the HD91+ gave an excellent performance, which made the lack of decent blacks more frustrating as it could really have been something special. As it is the HD91+ is a decent upgrade on the original and still at a reasonable price for the LED technology. If it had used a normal bulb at this price point we doubt it would have performed any better than the majority of well-priced single chip DLP models under £1000. But with the use of LED and the better colour reproduction because of that, we think it just about accounts for the price point and in a normal viewing environment it will produce its best. With the caveat of the black levels we still think it justifies a recommended badge. And there is nothing similar at this price point.

    The Rundown

    Contrast/Dynamic Range/Black levels


    Colour Accuracy


    Greyscale Accuracy


    Video Processing


    Image Uniformity


    2D Picture Quality


    Picture Quality Out-of-the-Box


    Picture Quality Calibrated




    Ease Of Use


    Build Quality


    Value For Money




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