On-Wall HT speakers - Home Theater Forum and Systems - HomeTheaterShack.com

 
Thread Tools
post #1 of 7 Old 05-01-12, 11:19 PM Thread Starter
New Member
 
Join Date: Sep 2011
Posts: 4
On-Wall HT speakers

I have some Dayton RS180S-8 and RS28f-4 drivers that I want to use for some HT speakers. My room does not accommodate floor-standing speakers positioned away from walls. I built a test enclosure that I have tested. The drivers have very nice response when located more than two or three feet away from a wall. In this configuration, I could make a really nice 2.5 way design with very flat frequency response. When positioned against the wall, however, I get some pretty severe cancelation between 150Hz and 250Hz. The enclosure depth is six inches. I'm not sure I see a good way to prevent this behavior. I considered a 2.5 way design using the second woofer to reinforce the attenuated frequency range. I am concerned that this will not help much because the same cancellation mode will apply to both woofers. I could se some ideas from anyone who has Experience with this issue.
mpickard is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 05-02-12, 09:12 PM
Shackster
John
 
Join Date: Apr 2008
Location: Lubbock, TX
Posts: 76
Best guess is that it is not a 1/4 wave cancellation from the front wall, unless the drivers are over 10" from the wall. Likely not enclosure resonance unless the enclosure has no bracing, but possibly room interaction? Is the dip in response in many locations?

JSS
maxmercy is offline  
post #3 of 7 Old 05-02-12, 09:54 PM Thread Starter
New Member
 
Join Date: Sep 2011
Posts: 4
Re: On-Wall HT speakers

Thanks for the response. The enclosure has internal bracing and is very solid. Other measurements suggest that my issue is with the placement and not the enclosure itself. I have attached some pictures. The first one is with the speaker on the floor in my measurement room. The second is in my living room where I removed the furniture and repeated measurements to see if the issue is a room mode associated with my measurement room. I suspected not because the issue remains with gating conditions that should remove reflections from the walls (not the floor because it is too close). The speaker is 6 inched deep and sets almost against the floor in the measurement room. I get exactly the same response nulls measuring in both rooms of significantly different dimensions. One picture shows the speaker on top of a stool and a bucket. While these items do influence the results, they do not change the behavior I was trying to confirm. The first measurement was collected with the speaker in the center of the room and shows pretty nice response (excluding the baffle step response). There are two pictures of this measurement with and without smoothing. The second measurement was collected with the speaker against the wall. This measurement is also shown with and without smoothing. Against the wall, I get some pretty substantial disturbance between about 150Hz and 400Hz. The response null gets more narrow and lower in frequency as I move the speaker away from the wall. My original intent was to use the on-wall configuration with little or no baffle step compensation. Now, I am not so sure, unless I can figure out how correct the low-frequency response. Any suggestions are greatly appreciated.
Attached Thumbnails
On-Wall HT speakers-speak-meas-open.jpg  

On-Wall HT speakers-speak-meas-open-no-smooth.jpg  

On-Wall HT speakers-speak-meas-wall.jpg  

On-Wall HT speakers-speak-meas-wall-no-smooth.jpg  

On-Wall HT speakers-speak2_2.jpg  

On-Wall HT speakers-speak1_1.jpg  

mpickard is offline  
post #4 of 7 Old 05-04-12, 12:58 PM
Senior Shackster
 
fbov's Avatar
fbov
 
Join Date: Aug 2008
Location: Pittsford, NY
Posts: 302
Re: On-Wall HT speakers

I thought this thread sounded familiar... it looks very familiar. Always good to ask a lot of quesitons!

HAve fun,
Frank, who uses the same alias on all forums
fbov is offline  
post #5 of 7 Old 05-05-12, 05:37 AM
Shackster
Mike
 
Join Date: Sep 2008
Location: Perth West.Australia
Posts: 48
Re: On-Wall HT speakers

I can only guess that these speakers will not sound of their best hard against a wall. Either put them in the room, or go back to the drawing board. Cheers, Mike.
Seaxe is offline  
post #6 of 7 Old 05-08-12, 12:22 AM
Elite Shackster
 
RTS100x5's Avatar
RTS100x5
 
Join Date: Sep 2009
Location: Arlington, Tx.
Posts: 1,019
Re: On-Wall HT speakers

wouldnt a crossover redesign give you a flatter response ??

AVR - PIONEER SC 35 w PANGEA AC9 CORD
AC FILT - PANAMAX M5400
DISPLAY - PANASONIC TC-P54G10 54in 1080p PLASMA
MAINS + SURROUND - DIY w DAYTON PT2C-8 PLANAR MID/HIGHS + DAYTON 6.5 MIDBASS -
SUBS - (2) DAYTON 15" ULTIMAX
SUB AMP - ACURUS A250
HTPC - WIN7 ULT,INTEL I7 860,CORSAIR 800D,CORSAIR HX1000, 16 GIG CORSAIR,EVGA P55 MB, ATI 5970 VIDEO, ASUS HDAV DELUXE 1.3 w BURSON DISCREET OPAMPS,PIONEER BDRW, 3WARE 9650 w 4x CRUCIAL 64gb SSD's in RAID 0
RTS100x5 is offline  
post #7 of 7 Old 05-08-12, 06:53 AM
Shackster
John
 
Join Date: Apr 2008
Location: Lubbock, TX
Posts: 76
Re: On-Wall HT speakers

The main differences I see from the floor to the wall measurement is all the fiberglass surrounding the speaker on the floor position, absorbing any reflection that could cause a null. It does look like a placement issue. Absorptive treatments only 2" thick should solve problems, and wall rigidity (or lack of) can cause some problems as well, when compared to a concrete floor.

JSS
maxmercy is offline  
Reply

Bookmarks

Tags
ht , onwall , speakers

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



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



Posting Rules  
You may post new threads
You may 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 is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome