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i currently have 2 sawm40 12" sony subs


and my local bb has the sawm20 subs on sale clearance, im wondeirng whether i should buy the sawm 20 8" subs since theyre so cheap


my room is strange, there are a lot of dead spots in my room, even with the 12 inch subs you dont hear it in my room unless youre within a few feet of direct fire.


my room is about 15'x15'


its small yet bass dissipates very quickly in it. its pretty empty in my room.


im wondering if i should get two more 8" subs to help increase the size of the sweet spot?


since i dont know anything about cancelation and all that technical mumbo jumbo, what should i do?


will getting 2 more 8" subs help strengthen the bass? or am i being too greedy?
 

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Have you heard real bass before? It is subtle 99.9% of the time. It is that 0.01% that knocks your socks off (or more precicely, knocks crap off walls and shelves and cabinets).


You've probably got phase cancellation issues if you don't hear the bass from 2 SA-WM40 subs. Especially since you say it isn't like that directly in front of the sub. How do you have everything currently wired up?

Those SA-WM40's are pretty stout for a low price... 2 of them in a small room should be shaking the floor and walls quite a lot. Avia on DVD and a radio shack analog SPL meter are just about required to do a basic multi-sub setup. Test tone CD's and an SPL meter is better though.


Did you do any kind of proper testing for subwoofer placement? Where I'd start is this:

Start with only 1 sa-wm40 hooked up. Place sub in the corner, pop in a source with some low frequency tones and measure the SPL at the listening position. Now, hook up the 2nd sub in the same corner and check the SPL. It should read much higher, if not, start playing with the phase switches on the subs.

Alternate method:

Put 1 sub in listening sweet spot. Play low frequency tones, and crawl around on the floor and find where the bass is loudest (SPL meter is handy for this). Now, put 1 sub there. That is the spot which causes a "peak" at your listening spot. Now play around with the position of the other sub and play with the phase until you get max output from both at the listening position.


There have been a million-zillion posts about how to set up multiple subwoofers here at AVS. I suggest you use the search function, as I'm sure I left out some important steps somewhere... :D


Sorny
 

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I have a single SAWM40 in a room only a bit smaller than yours. I was able to flatten the response with an spl meter by using a old graphic equalizer in line with the sub. Without equalization I had dips and peaks of up to 10dB. Most people now cringe at the bass levels if I crank it. Getting rid of those dead spots also helps to eliminate having to 'ride' the remote volume during movies.
 
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