3.1 HDTV Theater Setup: Check my logic? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 8 Old 05-09-2013, 09:52 AM - Thread Starter
Member
 
CubicleCrusher's Avatar
 
Join Date: Apr 2013
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
I am a hobbyist at best with no training nor professional experience. I simply enjoy detailed music and feel that without proper sound, watching movies at home is a lackluster experience. I'm also a bit of a gadget-junkie and (as a computer programmer) I like technology. So I attempt to learn through reading - mostly on-line sources, and experimenting - often with used or refurbished equipment. My goal is to understand - at a hobbyist level - the science behind speaker placement and A/V technologies so that I can make appropriate choices for my own home theater and expand my appreciation for the audiophile systems which are out of my reach. So if there is anyone out there who will indulge me in confirming my logic/understandings at this point in time as it relates to 3.1 HDTV home theater setup, I'd appreciate it.

I also would like to know how people measure the "angles" involved in the setups. I just recently discovered the world of Digital Angle Locators and wondered if this was part of an audiophiles tool kit or of you all just approximated angles with your eyes. Not trusting my eyes when it comes to anything other than 45 or 90 degree angles, I'm looking for a way to double-check my eye-ball measurements.

How do you measure the angles in a home theater set up?

And, if you've read this far - then it's onto my statements regarding a 3.1 HDTV Theater Setup:

3.1 Speaker Placement is the same as 5.1 - minus the two surrounds.

Speaker placement should be such that the tweeters are at the same height across the front sound stage. This height should also match the ear-height of the average listener when seated. This is due to the directional sensitivity of the higher frequencies. If the height cannot be matched, then the speakers should be angled and "aimed" at the ear-height of the sweet-spot. Placing 2 front speakers on appropriate height stands and then angling the center channel up-or-down according to it's placement is a common work-around for placement issues across the front sound stage. The three points consisting of the Front Left Speaker placement, Sweet Spot, and Front Right Speaker placement should form an equilateral triangle.

Despite the technological limitations of many center channels, a 3.1 system is still superior to a 2.1 system for home theater use. There are some limits here. The center channel should be at least 3 (or 4) feet away from the mains to avoid disruption and a possible reduction of sound quality. Also, a 3.1 system of "lesser speakers" could perform worse than a 2.1 system with "quality" speakers so the addition of a center channel shouldn't be chosen at the "expense" of good main speakers. But with all things otherwise equal, the addition of a center channel improves dialogue and is a worthy investment.

Sub woofers are more efficient (louder?) as you position them closer to side walls and corners. However Dolby recommends avoiding corner placement, and many sub-woofer recommendations admit you need to move the sub around a bit to get the best spot. One technique I've seen for this is to place the sub in (or as near as possible) the sweet-spot of the listener. And then shuffle around on your knees to various placement options. The place where the bass sounds the best is where you should put the sub. Many THX and Dolby diagrams show the sub-woofer placed between a front speaker and the display screen. Horizontal placement of the sub-woofer seems more important than vertical considerations since the lower frequencies tend to be omni-directional.

THX recommends that the top of the HDTV screen not be above a 15 degree angle from eye-level. It also recommends a 40 degree (or less) horizontal viewing angle, which often results in very large screen size recommendations. They are trying to simulate a cinematic experience after-all; so the horizontal viewing angle can vary. One thing seems certain, in home theater HDTV setups - don't put the screen too high. Not much science here, it's a comfort thing. Raising the screen up to achieve a "flat" horizontal line between the tweeters in the front sound stage is purely personal preference.

So - that's it! How'd I do? Am I on pretty solid ground with those statements/understandings or did I mess something up? smile.gif
CubicleCrusher is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 05-09-2013, 10:09 AM
AVS Special Member
 
Ethan Winer's Avatar
 
Join Date: Apr 2003
Location: New Milford, CT, USA
Posts: 5,748
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 133
Quote:
Originally Posted by CubicleCrusher View Post

How'd I do? Am I on pretty solid ground with those statements/understandings or did I mess something up?

You did very well! There are a few things I'd correct, such as how best to place a subwoofer, and you overlooked bass traps and other acoustic treatment entirely. But overall you certainly understand the basics.

--Ethan

RealTraps - The acoustic treatment experts
Ethan's Audio Expert book

Ethan Winer is offline  
post #3 of 8 Old 05-09-2013, 11:33 AM - Thread Starter
Member
 
CubicleCrusher's Avatar
 
Join Date: Apr 2013
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Thanks Ethan, some links you provided in other threads ended up being some of my main reading material. Though I can't remember exactly what sources they were - I remember a fairly detailed guide on setup and placement. I've read so much, and bookmarked so little, I often get my sources mixed up and can't remember "where" I saw what advice.

Admittedly, acoustic treatments seem excessive to me in relation to a mostly-casual listening environment. I'm unsure if the audio improvement is an adequate return on investment. However, I fully admit I need to learn more about these - even if I don't employ them I'm curious about the science and anticipated, audible, effects. I understand there are some DIY options regarding treatments, but I can't say I've seen any "refurbed" or "used" treatments for sale.

Clear guides on sub placement have been difficult to find. Lifting subs seems to be a debatable subject. My subwoofer owners manual encourages corner placement but Dolby guidelines expressly warn against it. I know I'm not satisfied with my current placement in that I feel it's too muddy in certain situations (perhaps source media related, but I still want to try and improve it).

Also, with the lack of any digital tool to evaluate the sound - I'm left with my aging ears to tell me what is optimal or not. Loving gadgets as I do, I can see me slowly getting into whatever digital techniques there are to evaluate sound (REW - whatever - I'm way behind on that topic!). Meters, Digital Angle Locators and various other gadgets will undoubtedly find their way into my toolkit.

If you have any favored links/reading material that I can use, feel free to share. I'll try to bookmark them this time. smile.gif
CubicleCrusher is offline  
post #4 of 8 Old 05-09-2013, 11:46 AM
AVS Addicted Member
 
sdurani's Avatar
 
Join Date: Oct 2001
Location: Monterey Park, CA
Posts: 19,147
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 835 Post(s)
Liked: 780
What are the room dimensions? Is it a closed room (doors) or open (archways or open floor plan)? This will help when making suggestions for subwoofer and speaker placement.

Do you already own any of the gear (speakers, subs, TV) that you plan on using in your 3.1 set-up or are they still up for purchase?

Sanjay
sdurani is online now  
post #5 of 8 Old 05-09-2013, 08:57 PM - Thread Starter
Member
 
CubicleCrusher's Avatar
 
Join Date: Apr 2013
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Quote:
Originally Posted by sdurani View Post

What are the room dimensions? Is it a closed room (doors) or open (archways or open floor plan)? This will help when making suggestions for subwoofer and speaker placement.

Do you already own any of the gear (speakers, subs, TV) that you plan on using in your 3.1 set-up or are they still up for purchase?

Hi sdurani - I was speaking in generalities because I'm still building (or re-building as it were). I'm currently working on the "Family Room" - an open-concept area that also incorporates the kitchen. The total open area of this space is approximately 13' wide and 35' long with 8' ceiling. The listening space is appx 13' square with a 5' opening/arch on one side wall and no "back wall" - the floor is laminate wood with area rug - a mix of hard-and-soft surfaces. Behind the listening couch is the open kitchen - tile floor - raised bar - harder surfaces. So as you sit on the center cushion of the listening couch, the 5' opening is to the left, the kitchen space is behind - another couch is on the right and the AV center is on a solid wall with no windows. This "sweet spot" is 9' from the existing HDTV.

This is the first of 3 rooms I'll eventually need to set up. I'm not 100% sure how much of this equipment will stay in this room.

I have a 50" Panasonic Plasma - a few years old - 2010-ish. It's the TC-P50S2. I know I can go bigger, and I will some day - but for now it stays. It is on a TV stand - centered against a solid 13' wide wall.

I'm using a refurbed Marantz NR1602 AVR. 50w/ch - 8ohm. I'm running a single HDMI connection to the HDTV with a 2.1 speaker configuration.

I have new Wharfedale 10.2's as my main speakers (6ohm, 40-24kHz) - currently sitting at 28.5 inches high, but I'll be putting them on 30" stands soon. I have the Klipsch RW-12D as a sub. The speakers are currently 8' apart but I'll widen them out (most likely) when I get my stands. My sub is against the left-side wall (as you look at the TV) - approximately 2 feet into the room/away from the back-wall corner; right before that 5' wide opening. The sub is further away from the TV than the mains - just on the "outside" of the left front main.

Not sure if you follow that rambling description or not, but it's an attempt to describe what I'm working with. Basically I have a 13X13 listening area in a larger 13X35 open space.

Given my statements in the original post about 3.1 theory - I feel that I'm on the "edge" of needing a center channel or not. Final speaker placement will probably settle it; if I can keep the main speakers 9 feet apart (or more), then I'll definitely incorporate the center channel. However, if I have to stay around 8 feet between L/R mains - I'm not sure if I'll opt for a center or not. I'll have to raise my TV, or mount the center below the TV and angle it upwards towards ear-height - or lower my mains and slouch in my seating position. wink.gif But Wharfedale has a pretty beefy center in the 10.CM and a lighter one in the 10.CS. I "want" it, but not sure if I "need" it. ~heh~

I plan on experimenting with my sub placement by putting it "inside" the equilateral triangle - positioning it between the left front main and the TV. This could also help me spread my mains further apart. But if I end up losing low end punch, I may need to keep that sub against a side wall and/or near(er) to a corner - or do something else as enlightenment comes.
CubicleCrusher is offline  
post #6 of 8 Old 05-09-2013, 11:51 PM
AVS Addicted Member
 
sdurani's Avatar
 
Join Date: Oct 2001
Location: Monterey Park, CA
Posts: 19,147
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 835 Post(s)
Liked: 780
Quote:
Originally Posted by CubicleCrusher View Post

Wharfedale has a pretty beefy center in the 10.CM and a lighter one in the 10.CS.
Neither one looks anything like your Diamond 10.2 speakers. If you can get another pair of those bookshelf speakers (new or used), I would use one of them as the centre speaker.

Since you already have a 2.1 set-up and a good receiver, you're most of the way there. Shouldn't be too difficult to add just one more speaker to your current system.

Sanjay
sdurani is online now  
post #7 of 8 Old 05-10-2013, 04:08 AM - Thread Starter
Member
 
CubicleCrusher's Avatar
 
Join Date: Apr 2013
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Quote:
Originally Posted by sdurani View Post

Neither one looks anything like your Diamond 10.2 speakers. If you can get another pair of those bookshelf speakers (new or used), I would use one of them as the centre speaker.

I wish they sold bookshelf speakers individually. And aesthetically, the center would look better than a single bookshelf sitting on the TV Stand. I've heard it said quite often that the best choice is to have 3 of the same front speakers. And the theory makes sense. I will like to experiment with a set-up like that, but I'm not sure the Family Room is the place to do it. When I get around to my Man-Cave it could be a different story. smile.gif

Some days I wonder if a 2nd Sub would be more value-added than a center channel in this Family Room area.

But on the whole I like sitting on the couch - sipping a drink - contemplating my set-up, fine-tuning, and equipment upgrades. And now, finally, I have a reason to stop at lawn sales with the wife or comb the depths of internet for those "irresistible deals"! I'm happy with my 2.1, don't get me wrong - but a guy can dream sometimes.
CubicleCrusher is offline  
post #8 of 8 Old 05-10-2013, 12:44 PM
AVS Special Member
 
Ethan Winer's Avatar
 
Join Date: Apr 2003
Location: New Milford, CT, USA
Posts: 5,748
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 133
Quote:
Originally Posted by CubicleCrusher View Post

I'm unsure if the audio improvement is an adequate return on investment.

The acoustics of your room arguably affect the sound you hear more than anything else, even including the loudspeakers. The room in this video is heavily treated, but it shows the enormous improvement possible:

Hearing is Believing

Even 1/8th that much treatment would make a very real difference.
Quote:
My subwoofer owners manual encourages corner placement but Dolby guidelines expressly warn against it.

I'm a big fan of corner placement, though that works best when the room has bass traps. If you live anywhere near me in western Connecticut, you're welcome to visit and hear for yourself how well corner sub placement (and acoustic treatment generally) can work.
Quote:
I can see me slowly getting into whatever digital techniques there are to evaluate sound (REW - whatever - I'm way behind on that topic!).

A tool like REW is indeed the only way to know for sure where your sub is best placed. This might help:

Room Measuring Primer

--Ethan

RealTraps - The acoustic treatment experts
Ethan's Audio Expert book

Ethan Winer is offline  
Reply Audio theory, Setup and Chat

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off