Skip to main content

Active vs. passive 3D TV technology: What’s the difference?

TV makers are introducing 3D HDTVs at a fast and furious clip. For example, Panasonic has 14 new ones, Vizio five, LG seven…the numbers keep piling up. Screen sizes range from 32- to 70-inches, and there are enough features and price variations to make your head spin. We’ll leave those specifics for another day. What we want to address is the issue of the 3D technologies you’ll encounter as you don your glasses and gaze at the infamous wall of flat panel TVs at the local store.

The practical difference

Active and passive 3D technology are two rival systems for accomplishing 3D effects, both competing for your money. We’ll get into the mechanics shortly, but the key differences are the 3D glasses supplied with each type of set. Passive glasses are similar to ones handed out at the movies: They’re light, cheap and do not require any power. LG, for example, includes four pair with its new models, such as the recently reviewed the 47LW5600. We reported the 3D experience was quite good, and the price for the 3D eyewear is definitely right.

LG passive 3d glassesLG passive 3D glasses

Active 3D glasses are bulkier, heavier, require battery power and cost a lot more than their passive counterparts. Typically, one or two pairs are supplied with a new 3D TV, while additional glasses cost anywhere from $50 to $179 per pair. Want to invite a bunch of friends over to watch Tron in 3D? Get ready to spend. That said, the quality is better, with much finer detail and the extensive sense of depth one expects from 3D HDTV.

Sony active 3D glassesSony active 3D glasses

How they work

Active 3D HDTV, which uses active shutter glasses, is a sequential system. All 1080 lines of resolution are beamed from the TV display panel to your eyes. An infrared signal paired to the supplied eyewear opens and closes the left and right lenses of the glasses at a very rapid rate, hence the term active shutter. Your brain perceives these fast-moving alternating frames as 3D. The important fact to note is the amount of resolution – 1080 lines. Active models are often labeled Full HD 3D.

The vast majority of passive 3D HDTVs use panels are supplied by LG Display, which operate on Film Patterned Retarder (FPR) technology. The 3D effect is created when the set’s left and right images are viewed with polarized glasses. Instead of active’s sequential frames, it’s an odd/even system and resolution drops to 540 lines to each eye, but you perceive high-def 3D. The glasses do not have to turn on and off; they just rest there “passively.” That’s why they’re so cheap, light and in our view, more comfortable. The system works well, and besides the fact quality isn’t as good as a top-tier active shutter HDTV, they are less forgiving in terms of placement; you really have to be at eye level for the best 3D effect.

What do they look like?

We recently sat through a side-by-side comparison of a new Panasonic plasma using the active system versus a passive 6500 series LG 3D LED LCD HDTV. The difference was dramatic as the detail and effects of the Panasonic looked far crisper and more realistic. A still image was shown of a guitar on both screens. The strings on the LG had jagged edges, and turned into double lines as you stood up and moved off center. The Panasonic held rock steady. We know this is not a true apples-to-apples comparison as plasmas use a faster self-illuminating technology that’s far more responsive than any LCD on the market. This speed is the reason plasma 3D effects have less blur and crosstalk, which you see as double images on the screen. Competitors readily admit plasma has an inherent advantage over LCD because of this faster response time. So if you’re looking for the absolute best quality in 3D as well as 2D, plasma is the way to go. They also admit plasma doesn’t lend itself to passive technology—it’s too difficult and expensive to implement.

panasonic 3d tv family
Image used with permission by copyright holder

The price of perfection

Now the price-versus-quality debate begins. Take a look at that wall of 3D HDTVs and check out new passive models from LG and Vizio. We gave the passive LG 47LW5600 an Editor’s Choice award because the 3D quality is very good, the price is right while the glasses are inexpensive and light. We have absolutely no problem recommending them. And yet active shutter 3D is better, especially on a plasma display. Those in the active shutter camp well know the sticker shock consumers face dealing with the cost of eyewear. That’s why Samsung recently dropped the price of its basic glasses to around $50, plus many of its sets come with two pair of active shutter glasses. You can expect similar price drops from other makers as the year progresses. Competition is a wonderful thing!

See for yourself

It’s hard to make sweeping pronouncements once you start comparing one specific model to another, as features and prices vary greatly. And unless you’re a total video geek you won’t have active and passive 3D HDTVs sitting side-by-side in your house. We’ll get on our soapbox now — it’s absolutely imperative you do a glasses-on comparison of the two technologies, compare features and then find your best price. You might opt for Vizio’s Theater 3D, LG’s Cinema 3D (both passive with lighter eyewear), a Sharp Quattron LCD or Panasonic Viera plasma with active shutter glasses as your final choice. Join an online debate if you feel strongly one way or the other. As for us, it’s all good. We just wish there was more 3D content to watch…

Editors' Recommendations

David Elrich
David has covered the consumer electronics industry since the "ancient" days of the Walkman. He is a "consumer’s"…
This CD/Walkman-inspired MP3 player aims to be the next mixtape
The Ninm Lab Playdisc.

Ninm Lab is obsessed with retro gadgets, from cameras to cassette decks, and its latest project -- the Playdisc -- reimagines the humble MP3 player as a digital version of the mixtape (or mixed tape for those old enough to remember the 1980s). The Playdisc will initially debut on Kickstarter on April 25 with a backer price of about $50. Once deliveries begin, which Ninm says will be in August, the devices should be available on the Ninm Lab site for around $71.

The Playdisc looks like CD case, complete with a transparent, hinged plastic cover, but its overall dimensions are smaller and thicker. You can use it with any Bluetooth headphones, and there's a 3.5mm jack for wired headphones too. It even ships with a set of wired earphones that take their inspiration directly from Sony's original Walkman and feature interchangeable foam earpads to complete the mashed-up retro look.

Read more
Best Paramount Plus deals: Get your first month free
Paramount Plus logo on an Apple TV.

Paramount Plus isn’t as big as some of the best live TV streaming services, but it has a lot of content people constantly want to binge or check in on. It’s home to the Yellowstone universe of shows, and every month what’s new on Paramount Plus includes a large variety of movies. Paramount Plus is a great standalone streaming service to turn to if you’re looking for something to watch. It comes in at a more affordable monthly price than most streaming services, costing just $6 per month or $12 per month when bundled with Showtime. But there are still ways to save on a Paramount Plus subscription, with several Paramount Plus deals to consider. Below you’ll find everything you need to know.
How to sign up to Paramount Plus for free for a week
The best way to go about watching Paramount Plus for free is by utilizing the Paramount Plus free trial. This is a pretty easy free week of access to claim, as all you have to do is sign up for a Paramount Plus account. The free trial is good for seven days, and it will give you full access to either the Paramount Plus Essential plan, which is regularly $6 per month, or the Paramount Plus with Showtime plan, which regularly costs $12 per month. Utilizing the Paramount Plus free trial is a great way to watch a particular sports event without having to commit to a monthly subscription, or to simply explore the Paramount Plus library to ensure there’s enough you’d like to watch before subscribing.

How to get a discount on a Paramount Plus subscription
If you're a student you can enjoy 25% off a Paramount Plus Essential monthly subscription. To do so, you simply need to verify your student credentials. You'll need to be a college or university student currently enrolled at an accredited, Title IV higher education institution to qualify.
How to save on your Paramount Plus annual subscription
An annual Paramount Plus subscription is a valid option if you're in it for the long term, as extended subscription will grant you some savings. Anyone who signs up for the Paramount Plus Essential plan for a year pays just $50 while the Premium plan costs $100. It works out as cheaper than subscribing on a monthly basis.

Read more
HD to 4K: these home theater projectors are up to $2,000 off
The Optoma UHD55 projector.

While TVs are great, if you want to have a large screen TV that goes over 80 inches, you're liable to spend thousands of dollars, and if you want to go over 100 inches, you may not even find any options at all, especially at the consumer level. Luckily, there are a lot of great projectors that can not only hit those targets but exceed them and do it at a much cheaper cost than a regular TV. Even better, there is quite a big sale right now at Crutchfield on home theater projectors, with everything from budget-friendly options to top-of-the-range stuff.

What you should buy in Crutchfield's projector sale
Not all projectors have to be incredibly expensive, and you can grab a great project for a good price with the Optoma HZ40HDR, which is , saving you a solid $450 in the process. It's an FHD projector, although it can handle 4k and HDR sources,  and the bulb has a 30,000-hour life span, which is pretty great for a budget-oriented projector. On the other hand, if you want 4k, Optomo has a good budget option for that too, the Optoma UHD35STx, which is a 4k short-throw projector with HDR10 and HLG HDR going , which isn't a massive discount on the usual $1,549, but it's still pretty good.

Read more