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help with adding 2nd sub


ousig
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a little background - I have had my Sunfire HRS12 for a year now and it is more than enough (is there ever enough bass?) for pretty much everything I can throw at it in my current situation. that being not having dedicated HT room and our current room/downfloor really isnt ever happy with trying to set up proper HT spacing and have 2 kids running around...it is basically a 13x16x9 room that opens to the kitchen/dining area, then to the entry/formal area. so only 3 walls.

anyway I saw on craigslist a deal too crazy to pass up - a Sunfire D-10 (model before the HRS-10 but exact same specs so a solid $500-$800msrp sub) for $80 total! I had previously tried the HRS 10 in my room and was amazed with the bass it could put out. no matter if at low volumes or full blast very low bass. This thing simply sounds great and can put out amazing clean bass if asked. Honestly guys you all need to hear these Sunfire subs to understand. I say this because I know so many dont believe that great bass can be had from boxes this size. And the visual UNimpact is great if you cant dedicate the space for a proper SVS beast :)

so back to my delima. I got the other Sunfire of course but I want to get them both setup if at all possible/reasonable. I have been reading on many sites and it seems that adding the 2nd sub isnt very easy, especially if you cant simply stack them in the same corner. with my room I cant, so currently I have my HRS up in the front left corner then I can put the D-10 in the back left corner basically in between a chair and our couch. So it is on the back wall.

honestly the bass with only the HRS has been more than enough but there are certain spots in the area that have very little bass so I wanted to add the other to clean that up but try not to cancel out the bass in other areas. Could I simply measure the distance from the listening position to each sub/2 and put that into the Denon setup and then run some test tones to confirm the best gain level on each sub to make it the most even?

Basically is there anything random I need to account for that I am not thinking of? right now I plan on playing test tones and measuring from a couple spaces with just the HRS playing. Then the same with only the D-10 playing. then the same with both playing and note the times where the bass isnt improved.

Then should I adjust the gain or phase on the D-10 to "smooth" it out?

I can post some pics later if needed

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Two subs will even out the bass response in the room. Stacking subs is not necessary. I use a sub near each main. A sub in the front left corner and right rear is another good placement option. Subs on opposing side wall is also a consideration. The biggest thing is getting them to the same phase. Level match ea. sub from the sweet spot with an spl meter to 73 db. I would start out with the phase set to 0 on both subs. I don't think you need to measure distances since Audyssey should take that into consideration. Audyssey should give up better bass performance since the subwoofer filter have 8x the resolution of the speaker filters. Dose your avr have one or two sub connections? Are you using a Y connector to run the two subs? After level matching check with an spl meter to see if the combined output is greater than 76 db. This should give you an ideal on cancellation problems due to phase. If it is less than 73, then slight movement of one of the subs may be all that is needed. The thing with the phase control on the sub will only correct one major frequency. REW analyzer is a good tool to use for the most accurate setup.

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I saw on craigslist a deal too crazy to pass up - a Sunfire D-10 (model before the HRS-10 but exact same specs so a solid $500-$800msrp sub) for $80 total!

You are right, hard to pass up a deal like that if it is functioning properly.

Honestly guys you all need to hear these Sunfire subs to understand. I say this because I know so many dont believe that great bass can be had from boxes this size.

I had a Sunfire True Subwoofer Signature for a while and it was a stick of dynamite in a firecracker package. Easy to get carried away with the volume if you don't watch it. My smallish Klipsch RSW-10d puts out a ton of clean, tight, and musical bass and I still may consider adding another one if the price is right at the right time.

It may take a while but do yourself a favor and trial and error as much as you are able, adjusting volumes, phase, and placement. I think you will be rewarded in the end.

Bill

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right now I have the sub out split then a y connector at each sub

ok thanks for the tips, I will play around and see what I can come up with. the only way I can use both is have them placed like I do now - the 12 in the front left corner and the 10 in the back left corner and this one is kind of boxed in with a chair and end of couch.

will run some frequency tones and find the peaks and valleys then try to blend for best overall even output.

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Here is a short but good read on setting up two subs: http://forum.blu-ray.com/showthread.php?t=95817

He never addresses setting phase with one sub in relation to the other or in relation to your mains. He only addresses levels.

He also says the 2 subs are ALWAYS better than one, which is not true. 2 subs can give less output at the listening position than 1 sub if the phase is off.

EDIT, he has 2 different sections on multiple subs. I was referring to the first section (connecting and setting up), he addresses phase in the second section (adjustment). It would be better if all the info was in one area (connecting and setting up).

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He never addresses setting phase with one sub in relation to the other or in relation to your mains.

He talked about phase is relationship with Audyssey further up in the paper: The phase control on the back the subwoofers is a usually a
simplistic analog control that only changes the phase at one frequency. Proper
phase alignment requires that the phase change is different at every frequency.
Unfortunately, that is not possible with an analog control. As a result,
Audyssey recommends that you leave the phase control at zero.

Also minor changes in the distance of one sub in the setup can help with phase problems.

Your are correct, if the subs are not setup correctly it can make things worse. Thanks for pointing that out.

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in responce to the phase question - I always thought that with subs in the back of the room the phase should be turned to 180 or at least adjusted from 0. What frequency does the sub phase adjust?

so it sounds like with new receivers no matter where your sub(s) are leaving the phase at 0 and adjusting volume or letting the receiver do it is probably the easiest

unfortunately so far I have not had time to really crank the system up and use my SPL meter to tell the difference/improvement/lack of with running the 2nd sub. that is life with 2 little kids!

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The key point is try adjusting the phase and see if it makes a diiference. The spl meter will come in handy along with a 2nd person. The thing that makes sub integration hard is eveyone has different avr, MCACC, Audyssey, vintage amp and DSP which changes the way to setup. For me, getting the subs of the floor raised the spl. My subs are not super expensive, but they are monters in the output department due to exciting room modes and have a stronger lower end than what their data sheets report. Sub specs are fine, but most were done in an open field or anechic chamber.

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