Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 6 1 2 3 4 5 6
Active LFRs and room treatment question
#445102 04/27/22 02:14 PM
Joined: Sep 2009
Posts: 1,893
Likes: 101
rrlev Offline OP
connoisseur
OP Offline
connoisseur
Joined: Sep 2009
Posts: 1,893
Likes: 101
This post is aimed at Ian and Andrew but others are welcome.

I’m building a combo HT and 2ch listening room. My thinking on the ALFRs is that they need a untreated front wall from behind the speaker to the side wall and untreated side wall from a few feet in front of the speaker to the front wall but I’d like to verify that.

What I like to know is if putting diffusion between them (behind the screen) is Ok.
Same goes for the absorption at the first reflection.

Guess the discussion I want to start is about treating rooms with active LFRs …

Re: Active LFRs and room treatment question
rrlev #445104 04/27/22 04:14 PM
Joined: Jun 2004
Posts: 287
Likes: 23
local
Offline
local
Joined: Jun 2004
Posts: 287
Likes: 23
I did find this article, particularly pages 22-24:

https://www.harman.com/documents/LoudspeakersandRoomsPt2_0.pdf

My interpretation is don't mess up an average room by buying acoustic treatments for an imaginary problem. haha

I think wall-to-wall carpeting and drapery will probably do more for a room than any acoustic paneling or diffuser ever will.


Author of "Status 101: How To Keep Up In A World That Keeps Score While Buying Into Buying Less"
Re: Active LFRs and room treatment question
rrlev #445111 04/27/22 10:51 PM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
Floor carpet and maybe a 5 foot thick mattress along the back wall and you're golden. The more homogenous all room boundary acoustic properties are the better.


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Active LFRs and room treatment question
rrlev #445113 04/28/22 12:45 AM
Joined: Sep 2009
Posts: 1,893
Likes: 101
rrlev Offline OP
connoisseur
OP Offline
connoisseur
Joined: Sep 2009
Posts: 1,893
Likes: 101
Hi Hambrabi,

I'm not one to over treat but I do experiment listen and measure ...
Trevor mentioned adding diffusion behind the screen (it's acoustically transparent ... well almost ... ~3db loss)
So I thought I'd try it but then got to thinking about how LFRs work and had this question and thought I'd see what people had to say.

Re: Active LFRs and room treatment question
Mojo #445114 04/28/22 01:16 AM
Joined: Sep 2009
Posts: 1,893
Likes: 101
rrlev Offline OP
connoisseur
OP Offline
connoisseur
Joined: Sep 2009
Posts: 1,893
Likes: 101
Originally Posted by Mojo
Floor carpet and maybe a 5 foot thick mattress along the back wall and you're golden. The more homogenous all room boundary acoustic properties are the better.
Guess you replaced your back wall treatment with a 5' thick mattress since your suggesting it ... I'm sure that must of been a upgrade from the furnace filters and fabric stuffing you had there previously ... anyway most of the stuff I read on back wall treatment suggest that diffusion works well in most cases ... an experiment for sure ...

Actually Mojo, I'm looking for carpet ... any suggestions on what type I should look at ...

Re: Active LFRs and room treatment question
rrlev #445115 04/28/22 01:54 AM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
I have 3/8" thick, 10 lbs density underpad with high quality berber. It's 15 yrs old and still looks brand new even though I've dragged speakers and subs all over it. Back in 2007, I paid 5 grand Can for stairs and 680 sq ft for removal and disposal of the old carpet and underpad, and installation and material of the new. It's warm and sounds fruity compared to the nutty sound of the old carpet.

Don't knock the furnace filters and stuffing until you try it. You may want to include a couple of in-line, galvanized aluminum humidifier evaporator pads halfway in between the furnace filters and the wall. I found improved separation of details with the M100s. With the actives, I don't need the pads.


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Active LFRs and room treatment question
rrlev #445119 04/28/22 03:57 AM
Joined: Sep 2009
Posts: 1,893
Likes: 101
rrlev Offline OP
connoisseur
OP Offline
connoisseur
Joined: Sep 2009
Posts: 1,893
Likes: 101
Ahhh, you still have the filters … and your giving away your valuable hard earned secrets telling people about the evaporator pads smile

Was thinking about berber … but also was wondering if what they use in theaters would be better. In the past I’ve had issues with rugs and carpets especially at high traffic points like doorways

Re: Active LFRs and room treatment question
rrlev #445120 04/28/22 04:19 AM
Joined: Jan 2007
Posts: 10,490
Likes: 116
M
shareholder in the making
Offline
shareholder in the making
M
Joined: Jan 2007
Posts: 10,490
Likes: 116
My doorways don't drag on the carpet. I also forbid shoes indoors. Such a filthy habit!


House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated
Re: Active LFRs and room treatment question
rrlev #445125 04/28/22 08:43 AM
Joined: Sep 2012
Posts: 1,037
Likes: 69
A
connoisseur
Offline
connoisseur
A
Joined: Sep 2012
Posts: 1,037
Likes: 69
How much room will you have behind your screen? I cant remember what CC you went with in the end. Vert OW180?

I would leave wall behind and beside LFRs open a few feet all around. The LCRs in my room have open back “Mid tunnels”. I had to remove absorbent SBIR traps. They sounded lifeless and dull. Smaller.

The neat thing about front wall diffusers is they work with lower frequencies and late reflections. Huge clarity benefit. I always say it deletes your impression of a fixed boundry, great for a huge screen with a diorama effect. A QRD is a great choice in this spot as you can make it deep with no penalty to room footprint if behind screen.

Pair that with the pop of a calibrated LX-NZ3….. just stupid good.

Re: Active LFRs and room treatment question
rrlev #445127 04/28/22 09:27 AM
Joined: Sep 2009
Posts: 1,893
Likes: 101
rrlev Offline OP
connoisseur
OP Offline
connoisseur
Joined: Sep 2009
Posts: 1,893
Likes: 101
Haven’t bought one yet. Still have my VP180HP which I’ll sell or trade … planning on getting a VP180ow … was going to hang it as intended to keep the tweeters in line. If I wasn’t planning for masking I would have gone with a M180ow and made the area below screen also AT.
Have you heard the VP!80 vertically?

how deep do I need for a QRD? Currently I have 6” …

The projector should arrive sometime in June … it a LS12000

Page 1 of 6 1 2 3 4 5 6

Moderated by  alan, Amie, Andrew, axiomadmin, Brent, Debbie, Ian, Jc 

Link Copied to Clipboard

Need Help Graphic

Forum Statistics
Forums16
Topics24,940
Posts442,457
Members15,616
Most Online2,082
Jan 22nd, 2020
Top Posters
Ken.C 18,044
pmbuko 16,441
SirQuack 13,840
CV 12,077
MarkSJohnson 11,458
Who's Online Now
0 members (), 563 guests, and 1 robot.
Key: Admin, Global Mod, Mod
Newsletter Signup
Powered by UBB.threads™ PHP Forum Software 7.7.4