LFE Question - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 1Likes
  • 1 Post By Alan P
 
Thread Tools
post #1 of 18 Old 02-15-2015, 10:09 PM - Thread Starter
Newbie
 
James Martin II's Avatar
 
Join Date: May 2014
Location: Chandler, AZ
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
LFE Question

Hello, Im new here to AVS and been trolling for awhile and have a question about LFE. I'll start with my planned set up. I'm looking at getting the Denon X7200w with an Emotiva UPA-7 amp, my speaker setup is Polk RTI A7's for fronts, CSI A6 Center Channel, RTI 4's for surrounds and surround backs and a PSW 110 sub woofer. OK so on with my question what I am looking at doing is on the A7's is bi amping them by passing the passive filter on the sub woofers and splitting off one of the LFE Channels on the receiver to the AMP and to the speakers. so i am wondering is the LFE channel only pass audio in the LFE frequency range? will this be too much for the speakers to handle?

Thank you
James
James Martin II is offline  
Sponsored Links
Advertisement
 
post #2 of 18 Old 02-16-2015, 01:59 AM
AVS Forum Addicted Member
 
sivadselim's Avatar
 
Join Date: Oct 2004
Location: Nashvegas
Posts: 16,638
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 489 Post(s)
Liked: 410
Although it's not absolutely clear to me exactly what you are trying to do, it IS clear enough for me to recommend you not do it.

If you REALLY want to spread the LFE channel into your speakers, consider setting your AVR up as having NO SUB connected and connecting your sub to the front channels, either via your AVR's front channel pre-outs (if so-equiped) or via a speaker level connection, with the sub's own low-pass filter adjusted to your A7's roll-off. This will reroute the LFE channel to the front channels where it will be spread across and reproduced by your front speakers and your subwoofer.

"All men are frauds. The only difference between them is that some admit it. I myself deny it."
sivadselim is online now  
post #3 of 18 Old 02-16-2015, 03:14 AM
FMW
AVS Forum Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 7,480
Mentioned: 13 Post(s)
Tagged: 1 Thread(s)
Quoted: 1654 Post(s)
Liked: 1710
The concept is to use a subwoofer for LFE. That is what you should do. Don't waste any money on passive biamplification. No point in it at all. Not even a little.
FMW is offline  
Sponsored Links
Advertisement
 
post #4 of 18 Old 02-16-2015, 03:35 AM
AVS Forum Special Member
 
NODES's Avatar
 
Join Date: Sep 2007
Posts: 1,904
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 653 Post(s)
Liked: 276
you have great gear... get a real sub to make it sound amazing.

Who needs 4K?... just go see your optometrist.
NODES is offline  
post #5 of 18 Old 02-16-2015, 03:37 AM - Thread Starter
Newbie
 
James Martin II's Avatar
 
Join Date: May 2014
Location: Chandler, AZ
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Ok thank you for your input.
James Martin II is offline  
post #6 of 18 Old 02-16-2015, 03:40 AM - Thread Starter
Newbie
 
James Martin II's Avatar
 
Join Date: May 2014
Location: Chandler, AZ
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Ya I'm saving up for a SvS pc12 sub. Been eyeing one for awhile now
James Martin II is offline  
post #7 of 18 Old 02-17-2015, 04:00 PM
AVS Forum Addicted Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 12,084
Mentioned: 116 Post(s)
Tagged: 0 Thread(s)
Quoted: 6608 Post(s)
Liked: 6023
Alan P is offline  
post #8 of 18 Old 02-18-2015, 11:42 AM
AVS Forum Special Member
 
fbov's Avatar
 
Join Date: Nov 2006
Location: Bushnell's Basin, NY
Posts: 1,644
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 332 Post(s)
Liked: 205
Quote:
Originally Posted by FMW View Post
The concept is to use a subwoofer for LFE. That is what you should do. Don't waste any money on passive biamplification. No point in it at all. Not even a little.
+1

Why use a subwoofer? The only unforgiving reason is sound quality.

I went into this in detail on another thread. The gist is that speaker locations are fixed by imaging requirements, while subwoofer locations can be optimized to reduce the room mode/standing wave pattern.

Everyone's familiar with the Dolby recommendations for 5.1/7.1/etc. speaker placement, which are based on the program fed to that speaker, L/R, center and surrounds. Placement matters because the frequencies produced are directional, and the program calls for direcitonal cues in specific locations.

Low frequencies are omnidirectional, so it's not possible for the program to require a specific location. Low frequencies interact very differently with the room than higher frequencies (discussed in the link), interacting directly with boundaries to set up standing wave patterns. Subwoofer locaiton in the room is one tool for optimizing (minimizing) the strength of the standing wave pattern, so it's a good thing the location can vary without impacting the program. That's no longer true if any of the other speakers are also producing the LFE program.

Have fun,
Frank
fbov is offline  
post #9 of 18 Old 02-18-2015, 09:42 PM
AVS Forum Addicted Member
 
sivadselim's Avatar
 
Join Date: Oct 2004
Location: Nashvegas
Posts: 16,638
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 489 Post(s)
Liked: 410
Quote:
Originally Posted by NODES View Post
.......................get a real sub to make it sound amazing.
Yep. With that sub and those towers it is certainly understandable why the OP is interested in having his main speakers reproduce some LFE. The two towers may well outperform the sub, particularly in the slam/punch department.

"All men are frauds. The only difference between them is that some admit it. I myself deny it."
sivadselim is online now  
post #10 of 18 Old 02-19-2015, 11:19 AM
AVS Forum Special Member
 
JHAz's Avatar
 
Join Date: Mar 2009
Posts: 4,587
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 307 Post(s)
Liked: 280
There are two technically unrelated things that get smooshed together for lfe. First, depending on the size of the baffle, below some frequency with typical box speakers sound starts emanating omnidirectionally. Second, our ear-brain systems do not identify directionality below some frequency. There are speakers (can't remember the name of the german speaker with the fire hydrant looking tweeter) that emit highs omnidirectionally. You can still identify direction. otoh, it is the third harmonics and above that identify where the lowest note of a bass is, and it simply does not matter, from a directional perspective where the lower frequencies cone from. If you are human your ears cannot identify the direction from which a 40-80 Hz tone emanates. But the 160 Hz and 320 Hz parts of the sound start to directionalize .. .
JHAz is offline  
post #11 of 18 Old 02-19-2015, 12:29 PM
AVS Forum Special Member
 
DreamWarrior's Avatar
 
Join Date: Nov 2005
Location: Dirty South Jersey
Posts: 2,279
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1062 Post(s)
Liked: 634
Quote:
Originally Posted by JHAz View Post
*snip* There are speakers (can't remember the name of the german speaker with the fire hydrant looking tweeter) that emit highs omnidirectionally. *snip*
MBL 101E? If I were rich, I'd put together a cigar/wine lounge in my home and these would be in it just because they look like sex, lol.
DreamWarrior is offline  
post #12 of 18 Old 02-19-2015, 12:37 PM
AVS Forum Addicted Member
 
Alan P's Avatar
 
Join Date: Jan 2003
Location: South Dakota
Posts: 12,084
Mentioned: 116 Post(s)
Tagged: 0 Thread(s)
Quoted: 6608 Post(s)
Liked: 6023
Alan P is offline  
post #13 of 18 Old 02-19-2015, 12:44 PM
AVS Forum Special Member
 
DreamWarrior's Avatar
 
Join Date: Nov 2005
Location: Dirty South Jersey
Posts: 2,279
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1062 Post(s)
Liked: 634
Lol, but what about this guy:



Audio sculpture! I suppose I'm just nuts, lol.
DreamWarrior is offline  
post #14 of 18 Old 02-19-2015, 04:04 PM
AVS Forum Special Member
 
JHAz's Avatar
 
Join Date: Mar 2009
Posts: 4,587
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 307 Post(s)
Liked: 280
The mbl is exactly what I was thinking about. The primitive part of my brain expects them to expand or morph into Star Trek mankillers. Probably the sex would be good til then, though
JHAz is offline  
post #15 of 18 Old 02-19-2015, 07:10 PM
AVS Forum Addicted Member
 
sivadselim's Avatar
 
Join Date: Oct 2004
Location: Nashvegas
Posts: 16,638
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 489 Post(s)
Liked: 410
Ohm Walsh


"All men are frauds. The only difference between them is that some admit it. I myself deny it."
sivadselim is online now  
post #16 of 18 Old 02-19-2015, 07:35 PM
AVS Forum Special Member
 
Soulburner's Avatar
 
Join Date: Oct 2007
Location: Lincoln
Posts: 5,346
Mentioned: 50 Post(s)
Tagged: 0 Thread(s)
Quoted: 194 Post(s)
Liked: 1873
If you don't already have the emotiva, skip it and add the money to your sub budget.
Soulburner is offline  
post #17 of 18 Old 02-23-2015, 06:42 AM - Thread Starter
Newbie
 
James Martin II's Avatar
 
Join Date: May 2014
Location: Chandler, AZ
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I got a good deal on the amp and am using 4 of the seve channels to power atmos speakers for 7.1.4 and was thinking of ways to uses some of the extra channels.

I am planning on picking up a better sub
James Martin II is offline  
post #18 of 18 Old 02-23-2015, 06:42 AM - Thread Starter
Newbie
 
James Martin II's Avatar
 
Join Date: May 2014
Location: Chandler, AZ
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Those speakers look wicked Kool.
James Martin II is offline  
Sponsored Links
Advertisement
 
Reply Audio Theory, Setup, and Chat

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