Previous Thread
Next Thread
Print Thread
Rate Thread
Page 2 of 6 1 2 3 4 5 6
Re: Multiple Subwoofer Set-Up & Calibration Guide
CV #305135 05/06/10 06:35 PM
Joined: Jul 2006
Posts: 12,057
Likes: 6
C
CV Offline
Founder, Axiom Upgrade Club
shareholder in the making
Offline
Founder, Axiom Upgrade Club
shareholder in the making
C
Joined: Jul 2006
Posts: 12,057
Likes: 6
I thought this way of calibrating the subs was interesting, in that I hadn't seen it before. I'm certainly not as well-read as a lot of you. I always assumed measuring at the listening position was the way to go. What do you guys think?

 Originally Posted By: gene
Good question. For years, I always measured at the listening area for each sub. It was a pain to match levels that way. Then it occurred to me when reading Dr. Floyd Toole's book that what matters is how the subs balance with respect to the room NOT the listening area. Remember in order to take full advantage of standing wave reduction, all subs must:
  • be level matched with respect to each other
  • be properly placed
  • play exact same mono signal (LFE + all speakers set small)
The easiest way to measure each sub is to place the mic on the floor nearfield to the sub (within a few inches). If all your subs are single driver, then you can measure the SPL at the cone for each. You don't need to turn off the other subs if you do a nearfield measurement b/c the sound from that sub will dominate all others.

After you level match each sub, then go to the listening area and level match the main channels to the combined sub output. Once you flatten the bass of the subs, you can even boost their combined output a few dB over the main channels if you like.

Alternatively you can pick an equadistant point from all subs to measure their SPL individually but that can be difficult if they aren't all symmetrically placed in the room.


Re: Multiple Subwoofer Set-Up & Calibration Guide
JohnK #305170 05/06/10 10:42 PM
Joined: Dec 2007
Posts: 7,786
axiomite
Offline
axiomite
Joined: Dec 2007
Posts: 7,786
 Originally Posted By: JohnK
If you read the book at pp.226-227,...

John, do you have a photographic memory?


Fred

-------
Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
Re: Multiple Subwoofer Set-Up & Calibration Guide
fredk #305181 05/07/10 01:24 AM
Joined: May 2002
Posts: 10,654
shareholder in the making
Offline
shareholder in the making
Joined: May 2002
Posts: 10,654
Fred, I've got the book; so even if I got one of them pornographic memories I didn't need it for this.


-----------------------------------

Enjoy the music, not the equipment.


Re: Multiple Subwoofer Set-Up & Calibration Guide
JohnK #305190 05/07/10 02:15 AM
Joined: Nov 2008
Posts: 1,789
connoisseur
Offline
connoisseur
Joined: Nov 2008
Posts: 1,789
Its wierd seeing the two 'K's talking directly to each other like this. I've always envisioned you two as siamese twins connected at the shoulders. Each with your own computer and keyboard, your own identity and all that good stuff...

But I guess I always figured if you ever wanted to say something to one another, you would just turn your head and say, "dang, you got some kinda photographic memory bro? I didn't get one of them darn it".


My Stuff :

M80's
QS8's
VP150
EP800
Denon 4802
Emotiva XPA-3
Samsung BD-P3600
Sharp 65 Inch Aquos LCD
Re: Multiple Subwoofer Set-Up & Calibration Guide
Micah #305355 05/07/10 11:53 PM
Joined: Dec 2007
Posts: 7,786
axiomite
Offline
axiomite
Joined: Dec 2007
Posts: 7,786
I did turn, but he had a book in his face.


Fred

-------
Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
Re: Multiple Subwoofer Set-Up & Calibration Guide
JohnK #305357 05/07/10 11:56 PM
Joined: Dec 2007
Posts: 7,786
axiomite
Offline
axiomite
Joined: Dec 2007
Posts: 7,786
John, you have a lot of enthusiasm for this hobby then. I'm happy to point people in the direction of reference material, but I am not motivated enough to look up specific page references to make a point.


Fred

-------
Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
Re: Multiple Subwoofer Set-Up & Calibration Guide
CV #305370 05/08/10 12:24 AM
Joined: Dec 2003
Posts: 10
G
GDS Offline
frequent flier
Offline
frequent flier
G
Joined: Dec 2003
Posts: 10
Guy's

I've been in constant contact with Dr. Toole, and the senior folks at Harman (Sean Olive, Tod Welti). I don't want to speak on anyones behalf but Floyd was pretty clear to me that he preferred 4 corner placement with SFM (sound field management) vs 4 midwall placement with SFM or proper EQing. 4 midwall is very inefficient and a waste of sub power in most cases. I've never heard a 4 midwall placement that I thought exceeded a 4 corner placement or 2 midwall placement. I have Harman running real world tests and Matlab sims of my recommendations in my article and will be posting a followup. I also have some updates coming to this article based on my convos with Harman. They also invited me out to their facility to do further testing.

I've been slammed the last few days doing our annual speaker shootout for $1k towers which happened to include Axiom M60v3s. Very interesting results to post.

Rest assured there will be many followup articles to this sub article referenced here. Please also realize these are general recommendations to start with. Experimentation is key of course and not every configuration will be suited for any particular room. The main purpose of my article was to provide a methodical way to setup and calibrate multi subs to achieve the best results and minimize the guest work.


Best Regards; Gene DellaSala (GDS) Audioholics.com
Re: Multiple Subwoofer Set-Up & Calibration Guide
GDS #305378 05/08/10 01:18 AM
Joined: Dec 2007
Posts: 7,786
axiomite
Offline
axiomite
Joined: Dec 2007
Posts: 7,786
Hey, look what the cat dragged in. ;\)

I look forward to the sub articles and the speaker shootout. I'm curious to know how the M60 ranks against some of the more recent contenders in the $1k range.


Fred

-------
Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
Re: Multiple Subwoofer Set-Up & Calibration Guide
GDS #305379 05/08/10 01:20 AM
Joined: May 2002
Posts: 10,654
shareholder in the making
Offline
shareholder in the making
Joined: May 2002
Posts: 10,654
Gene, good to have you stop by again and comment on this topic discussed in your excellent article. As I pointed out, Dr. Toole specifically endorsed the two mid-wall arrangement with two co-located subs at each position as being the best, by a narrow margin, of the options for four subs.


-----------------------------------

Enjoy the music, not the equipment.


Re: Multiple Subwoofer Set-Up & Calibration Guide
CV #305388 05/08/10 02:13 AM
Joined: Dec 2003
Posts: 10
G
GDS Offline
frequent flier
Offline
frequent flier
G
Joined: Dec 2003
Posts: 10
Guys;

I updated the article to remove the "uneven" comment of 4 midwall sub placement and also added a comment about the 4 corner placement as follows:

Used in conjunction with global equalization, this option provides nearly as good frequency response and seat to seat variation as the midwall placement with the huge advantage in efficiency.

There is much more coming trust me. This article is already over 8600 words so I didn't want to turn it into a novel. Its also been read by many of the key players in the industry and most of them have an interest in furthering this topic for industry education since its very confusing to people how to properly setup multi subs.

Regarding the Shootout
The Axioms did nicely in the shootout and more importantly we ate a lot of great food, consumed mass quantities of beer, and had fun doing it. But moving around the speakers on carpeted floors was quite a pain \:\(


Best Regards; Gene DellaSala (GDS) Audioholics.com
Page 2 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
Topics24,800
Posts440,637
Members15,534
Most Online2,082
Jan 22nd, 2020
Top Posters
Ken.C 18,044
pmbuko 16,440
SirQuack 13,794
CV 12,057
MarkSJohnson 11,458
Who's Online Now
0 members (), 85 guests, and 2 robots.
Key: Admin, Global Mod, Mod
Newsletter Signup
Powered by UBB.threads™ PHP Forum Software 7.7.4