Dual SB3000 in small room

[TankTop5]

Recently moved my subs to my bedroom and ran Audessey XT (Marants SR5014) but I’m not getting the output I was looking for or expected.

Setup with subs at -10db and everything else is correct (one 180° out of phase), should I rerun it at -20db or is there a different suggestion? There are two floor AC vents, should I cover these when listening for effect and would these be enough for the subs to “see” a bigger room? 13’x14’x9’ so I should be getting ridiculous room gain. I have a king size bed so absorption shouldn’t be an issue but I’m also planning on adding a couple corner bass traps.

Also planning on upgrading to a Denon X3800H, can be found for $1k so I should probably pull the trigger.

 

[lovinthehd]

Where did you position the subs? Not familiar with the gain settings on SVS subs, what was the resulting trim level in the avr when you run at -10 or -20 on the SVS? Did you experiment with setting phase to same? Ridiculous room gain means what particularly? Squarish rooms can have issues....but covering the vents I doubt would do much (altho might reduce noise elsewhere in the house perhaps).

 

[TankTop5]

Both subs are on the same wall about 9 feet apart. Pretty sure I should move one either to the side or to the rear wall. The side toward the rear of the room would be the best with how the room is setup.

I didn’t mess with trim levels in the AVR, just set speakers to small and crossover at 60hz. Using my Dynaudio Contour 20’s and without measuring in room response figured they would have enough bass extension in that small of a room with them also being about 10” from the rear wall, not much I can do about that.

Also the King mattress takes up almost 70% of the floor space with great absorption but I know Ineed some bass traps and address reflections.

Read a little about room gain with longest wall lengths being less than 16’ giving significant gains below 35hz with sealed subs. Assumed a pair of SVS SB3000’s would be ridiculous in that room. I have them in a very large open apartment with 16 foot vaulted ceilings and a huge living room, and they were way too much for the apartment. They should be ludicrous in this bedroom so there’s something not right.

 

[shadyJ]

Both subs are on the same wall about 9 feet apart. Pretty sure I should move one either to the side or to the rear wall. The side toward the rear of the room would be the best with how the room is setup.

I didn’t mess with trim levels in the AVR, just set speakers to small and crossover at 60hz. Using my Dynaudio Contour 20’s and without measuring in room response figured they would have enough bass extension in that small of a room with them also being about 10” from the rear wall, not much I can do about that.

Also the King mattress takes up almost 70% of the floor space with great absorption but I know Ineed some bass traps and address reflections.

Read a little about room gain with longest wall lengths being less than 16’ giving significant gains below 35hz with sealed subs. Assumed a pair of SVS SB3000’s would be ridiculous in that room. I have them in a very large open apartment with 16 foot vaulted ceilings and a huge living room, and they were way too much for the apartment. They should be ludicrous in this bedroom so there’s something not right.

You would be getting more room gain with a typical sealed sub. The SB-3000 is not a typical sealed sub, because it has a high-pass filter that makes it behave more like a ported sub in the lowest octave.

 

[j_garcia]

For low bass, small rooms are worse, not better. A single 80Hz sinewave is 14ft, 40Hz is 28ft. As Lovin pointed out, the squarer the room, the worse cancellation is. Multiple subs won't exactly fix that.

 

[lovinthehd]

Both subs are on the same wall about 9 feet apart. Pretty sure I should move one either to the side or to the rear wall. The side toward the rear of the room would be the best with how the room is setup.

I didn’t mess with trim levels in the AVR, just set speakers to small and crossover at 60hz. Using my Dynaudio Contour 20’s and without measuring in room response figured they would have enough bass extension in that small of a room with them also being about 10” from the rear wall, not much I can do about that.

Also the King mattress takes up almost 70% of the floor space with great absorption but I know Ineed some bass traps and address reflections.

Read a little about room gain with longest wall lengths being less than 16’ giving significant gains below 35hz with sealed subs. Assumed a pair of SVS SB3000’s would be ridiculous in that room. I have them in a very large open apartment with 16 foot vaulted ceilings and a huge living room, and they were way too much for the apartment. They should be ludicrous in this bedroom so there’s something not right.

So you just plugged the subs into the avr and did no setup of levels?

 

[Wardog555]

Start with the subwoofer levels to 0 on both the receiver and the svs app and start from there.

 

[TankTop5]

So you just plugged the subs into the avr and did no setup of levels?

No, I ran Audessey, set sub gain -10 per instructions and set phase 180 in one sub. Mains set small crossed over at 60hz.

 

[TankTop5]

You would be getting more room gain with a typical sealed sub. The SB-3000 is not a typical sealed sub, because it has a high-pass filter that makes it behave more like a ported sub in the lowest octave.

I didn’t know that, is there a way to bypass the filter or something I can change in the SVS app? When I get time I’ll run some rew sweeps and see what I’m working with.

Just when I think I know something I learn I have a lot to learn.

 

[3db]

Difficult to assess without pictures. Why did you set phase 180 out on one sub? That to me is the single biggest reason in why you are lacking output. Its called cancellation. You'd be better off measuring the in room response with REW and looking at the curves to see what you have.

 

[TankTop5]

Difficult to assess without pictures. Why did you set phase 180 out on one sub? That to me is the single biggest reason in why you are lacking output. Its called cancellation. You'd be better off measuring the in room response with REW and looking at the curves to see what you have.

I thought setting one dive 180 was to avoid cancellations. They are almost 10’ apart. Thought close together set phase the same and they act like a single sub.

 

[3db]

I thought setting one dive 180 was to avoid cancellations. They are almost 10’ apart. Thought close together set phase the same and they act like a single sub.

That's what you want. Make the pair act like a single sub

 

[TankTop5]

That's what you want. Make the pair act like a single sub

It’s such a small room would it be a bad idea to do a sub crawl and just stack em?

 

[shadyJ]

I didn’t know that, is there a way to bypass the filter or something I can change in the SVS app? When I get time I’ll run some rew sweeps and see what I’m working with.

Just when I think I know something I learn I have a lot to learn.

I don't think you can bypass the high-pass filter too much. There is a lot of shaping you can do to the response with SVS's app, but it has a pretty strict filter in deep frequencies in order to protect the driver from over-excursion.

 

[3db]

It’s such a small room would it be a bad idea to do a sub crawl and just stack em?

No. What you are trying to do is use multiple subs to even out the bass response in the room so its more consistent as you move around the room. Putting two subs at essentially the same location won't do that.

Take a look at the Utube below. Never mind the MiniDSP part of the video. The presenter talks about how to measure with REW and how placement affects their response.

 

[lovinthehd]

No, I ran Audessey, set sub gain -10 per instructions and set phase 180 in one sub. Mains set small crossed over at 60hz.

Whose instructions? You set the sub gain after running Audyssey? Did you try the phase set at 0 for both? Try a higher crossover?

 

[ski2xblack]

With one sub's phase setting at 180 deg, it's perfectly out of phase with the other sub, pulling when the other sub is pushing, so it's no wonder you're getting no bass.

Unless it is required to get a seamless blend with your mains, you should probably leave them both at zero. You're relying on Audyssey for calibration anyway, give it a level playing field to work with.

 

[ryanosaur]

Never change phase unless there is a reason for it. Start at zero for both. Adjust them only if there is a problem not addressed through other common solutions.
Then, assuming you can control the Phase through the App, do so while listening to something with a regular persistent bassline that will allow you to hear if there is a change for the better. Follow this up with measurements.

 

[TankTop5]

I don't think you can bypass the high-pass filter too much. There is a lot of shaping you can do to the response with SVS's app, but it has a pretty strict filter in deep frequencies in order to protect the driver from over-excursion.

SVS just emailed me and stated LFE input bypasses filters

 

[shadyJ]

SVS just emailed me and stated LFE input bypasses filters

I am sure they mean low-pass filters. We are talking about high-pass filters.