Rule of thumb for screen size per distance from TV? (1 Viewer)

[Jeff Pounds]

I'm getting ready to start researching the upgrade I've been waiting for... a 16:9 HDTV!!! Finally!
Quick question before I start, though... it seems I remember reading somewhere that there is some kind of general rule of thumb about screen size you should get based on the size of your room and/or your disance from the display device.
My couch is approximatly 10' (maybe a little bit less) from the screen in my living room.
I've been casually browsing in electronic stores and it appears that I will need something in the 51-57" range, but it's really hard to tell if the device isn't in my living room.
Is this about right? What is the rule of thumb?
Thanks in advance...

 

[Michael TLV]

Greetings

3X the diagonal ...

or 4 to 6 times the height (analog interlaced)

or 1 to 3 times the height (HDTV)

I am 9' from a 61" 4:3 HDTV ... works just fine.

Regards

 

[Drew Eckhardt]

1.5 - 2 screen widths for DVDs yields an immersive experience not too revealing of flaws, and under 3.2 screen heights is required in order to visually resolve 1080i HD. A 72 x 40.5" (81" diagonal) 16:9 screen would work nice and will give you a smaller, more watchable picture on poor sources than the same width 4:3 screen.

For consumer one-piece sets that translates into "as big as possible"

Farther was required when we were stuck with 480i; although with affordable consumer sets and DVD players incorporating line doublers this is no longer the case.

 

[Christian C]

Here is a viewing distance calculator that may be helpful. Also lists SMPTE and THX recommendations for viewing distances. At 10', following SMPTE or THX you cannot go "too big" with a standard RPTV.

 

[Matt Stone]

At 8 feet...will a 50" 4x3 TV look alright. I'll mainly be watching standard cable and DVDs.

 

[Drew Eckhardt]

It's all a function of subtended field of vision. You can multiply any set measurement (diagonal, width, or height) by the ratio between viewing distances and end up with mostly (projectors may be dimmer on larger screens) equivalent numbers. For example, a hypothetical 60" diagonal set at 10' will look the same as a 48" set at 8' (60 * 8/10).

Beyond that, how sensitive are you to noise and softness, how bad is your cable provider, etc.

Personally, at 10' on a 72 x 40.5" display making for an 81" 16:9 diagonal and 67" NTSC I find all Echostar channels watchable (it's good for HBO, OK for many cable channels, and not bad for the rest), VHS not yet offensive, nearly all DVDs excellent, and good DVDs a bit small. Conversely a 90" NTSC diagonal (72 x 54") is right out for VHS, OK for the HBOs, and worse to unwatchable compared to a 67" diagonal on the rest (16:9 size is unaffected).

The 8' equal of my 72 x 40.5 display equates to a 65" 16:9 diagonal or 54" 4:3, suggesting that with my tastes 50" at 8' will be good for most 4:3 sources but small (at 45" diagonally) for 16:9.

Enter the real benefit of 16:9 - it makes your good sources bigger and better, without blowing your worst material up until bad things happen.

Also note that this implies a 480p _progressive_ source. I find interlaced video objectionable any closer than 8' from a 32" NTSC set. If they still sell analog 480i projection sets I wouldn't want one (although you might - it really is a matter of personal preference).

Visit your favorite shop, pace off distance from their RPTVs, and see how it works for you with the specific set you're interested in.