SVS pb12-ultra unfulfilled

[Hostility]

So ive had this sub for about a year, But i dont get to use it to often due to living in an apartment. Last night i watched x-men first class (awesome by the way), and i just didnt seem happy with the bass. I felt it a lot in the couch, but the bass didnt fill the room. It almost seemed like it was playing 30-20hz range and that was it. Crossover is set at 60hz. Now is this due to placement? i have all 3 ports open and lpf set at 20hz, sub is 10" away from the back wall. So im just wondering if its placement or the subwoofer itself?

If i was looking to sell this subwoofer, my thoughts were, PB12-plus (very similar to the one i own now but front firing ports what i like better), or SB-13 ultra, dual sb12-nsd, or paradigm sub 12 (used).

if anyone doesn't remember this sub, here is a link http://www.hometheatershack.com/forums/subwoofer-tests-archived/6008-svs-pb12-ultra-20-hz-tune.html#axzz2GY4iauue

 

[ImcLoud]

lpf set at 20hz, [/url]

???????????

Can you disable this and let your avr handle the crossing?

Also is the phase correct?

sub placement IMO is good for tweeking' but if you are unsatisified completly Im thinking it is a setting problem... Did you try running it HOT, turn up the gains and bias to the sub, or does it get boomy?

 

[Adam]

???????????

Can you disable this and let your avr handle the crossing?

I'm guessing that he meant the subsonic filter. In addition to plugging ports, the Ultras let you select the tuning of the sub.

 

[Hostility]

sorry yes adam is right i didnt mean LPF lol. I have let ARC on my anthem set the sub, and i actually ran it a bit hotter. phase ive tried 0 and 90, not 180 yet. I could try to play with that, but i thought that it wouldn't make that much of a difference as to what im wondering but i could be wrong.

Later today i will play with it a bit, i am also going to watch another movie tonight and ill see how it performs then.

 

[fuzz092888]

I'm guessing that he meant the subsonic filter. In addition to plugging ports, the Ultras let you select the tuning of the sub.

If he didn't mean subsonic filter then that could be the problem right there. If he had a low pass on 20 Hz, then that would perfectly explain why he felt he was only getting output in the 20-30 Hz range.

 

[fuzz092888]

sorry yes adam is right i didnt mean LPF lol. I have let ARC on my anthem set the sub, and i actually ran it a bit hotter. phase ive tried 0 and 90, not 180 yet. I could try to play with that, but i thought that it wouldn't make that much of a difference as to what im wondering but i could be wrong.

Later today i will play with it a bit, i am also going to watch another movie tonight and ill see how it performs then.

What floor apartment are you in? I remember living in an apartment in college on the second floor and always remember having most of my bass travel right through the floor into the apartment below. This was a huge contributing factor to why I always felt the bass was a bit lacking, perhaps something similar could be going on with you?

 

[Adam]

You might have said this already, but I forget - do you have an SPL meter? If so, I recommend running some test tones to check out the response at your listening position(s). Run the tones with your speakers off, and then run them with them on - that will let you know if there's interference between them and the sub causing a dip at certain frequencies. You'll also see if there's a dip period. I get those due to the room.

Does your sub amp have the parametric equalizer?

 

[Hostility]

I'm in a basement apartment, my subwoofer does have parametric eq. I did a quick test with some bass heavy music and I found that in the corners it obv was boomier. But almost felt when standing in the front stage it sounded good, so now I'm thinking the sub should have been placed there then beside my couch. Almost is like it gets that fuller bass every were by my seating position lol. So I convinced my gf to help me move the coffee table and couch when we get home later today and ill do a bass crawl. Unfortunately I don't have an spl meter but the Jl audio one on my iPhone lol

 

[fuzz092888]

Perhaps a room mode where you have the subwoofer placed? If you have one there, do a bass crawl, but look for the room mode again as well as the best location.

 

[KEW]

The crawl should be very helpful. I'm not familiar with the iphone microphone regarding lower frequencies, but it is better than nothing and the problem you describe shouldn't require exceptional accuracy to detect.

 

[ImcLoud]

When I first set up my basement theater the phase was oof on the dual subs and kept going back to 0 when I restarted them {that turned out being a problem I caused by shutting the down completely instead of just using the auto feature}, and I instantly noticed the subs were not firing how they should have been... I pick phase by playing a good bass-y song and toggling through the directions and one will always sound heavier, thats the one I pick....

Subs take the longest to setup, what I do after I have the sub where I want it {because here that is most important, I don't care if it sounds 150% better in the middle of the room tipped upside down, if I want it out of sight behind the couch that is where its going, plus I'm married and entertain very often so sadly aesthetics before performance.} is turn it all directions and test it in the limits of that location, so all the way to the left and away from the wall with the ports firing out, then play the song {Don't laugh but I use Adele "rolling in the deep", the bass in that song is perfect for sub testing}... Takes time but I always end up happy...

 

[Hostility]

Perhaps a room mode where you have the subwoofer placed? If you have one there, do a bass crawl, but look for the room mode again as well as the best location.

That's what I'm thinking also. Now will the couch sitting in the middle of the room affect anything or should I try to get it right out if there? Also how far Should the ports be from the wall? I rea some were at least 10"?

 

[Hostility]

When I first set up my basement theater the phase was oof on the dual subs and kept going back to 0 when I restarted them {that turned out being a problem I caused by shutting the down completely instead of just using the auto feature}, and I instantly noticed the subs were not firing how they should have been... I pick phase by playing a good bass-y song and toggling through the directions and one will always sound heavier, thats the one I pick....

Subs take the longest to setup, what I do after I have the sub where I want it {because here that is most important, I don't care if it sounds 150% better in the middle of the room tipped upside down, if I want it out of sight behind the couch that is where its going, plus I'm married and entertain very often so sadly aesthetics before performance.} is turn it all directions and test it in the limits of that location, so all the way to the left and away from the wall with the ports firing out, then play the song {Don't laugh but I use Adele "rolling in the deep", the bass in that song is perfect for sub testing}... Takes time but I always end up happy...

I'm in the same situation I only have 2 ideal choices which is either side of the couch or 1 spot out front that I would like to avoid. I can't really spin it left or right, 180 and you would see the rear of the sub all the time. I did try pushing it closer and away from the wall but didn't hear a massive difference. But hopefully with this sub crawl a little later today ill be able to find out what's going on. Thanks

 

[ImcLoud]

I'm in the same situation I only have 2 ideal choices which is either side of the couch or 1 spot out front that I would like to avoid. I can't really spin it left or right, 180 and you would see the rear of the sub all the time. I did try pushing it closer and away from the wall but didn't hear a massive difference. But hopefully with this sub crawl a little later today ill be able to find out what's going on. Thanks

While your down there I think I dropped a fifty dollar bill, but it could have been a different denomination, but just send it back if you find it... Also gold, if you find any gold, that is mine too... Good luck...

 

[Adam]

Hostility, have you run the ARC setup on your Anthem?

 

[Hostility]

Haha I am a bit curious as to what's under the couch lol. Adam yes I have I need to re run it but just waiting on the serial to USB cable

 

[Hostility]

Well i tried a few things. First bass crawl, but that didnt seem to help me, i listened to the places the sub could go (was playing music) and each corner had tons of boom, the front stage where i could place it sounded decent, so i put my couch back and put the sub beside the 1 main, and it sounded better on music. So i thought i would try with a movie. But i found that i lost all my low end that i could really feel and even the higher end wasn't that great. So i tried beside the other main and it was about the same. So then i tried the other side of the couch, and found it wasn't much better then my first spot. So im just curious if a sealed is better for my application being in a basement apartment. I could give up more low end for a bit more punch in the upper range and would help shake less stuff around the place (hoping not much moves upstairs :S)

 

[agarwalro]

I'm bringing this post over from a different discussion to help folks get a view of Hostility's room. The PB12U sub is hiding in the lower picture, behind the computer chair, on the right of the couch.

This is looking from 1 corner of the room (taken with iphone). the solid door goes into bedroom, the door to the left of it goes into the rest of the appartment/common room that leads into shared laundry. And as you can see far left is the bathroom and on the other side of that wall is laundry room.

This is looking from the opposite corner, the other door closed is just a closet.

Now when i watch movies loud, landlord is not home (when they are we watch at a reasonable level) and i close all doors.

I'm copying over my response from a couple of PMs we exchanged.

hey, thanks for the link to the article.

You're welcome! The complete article is a great resource for using REW and achieving good quality bass.

I noticed in your sig you have/had the svs pb-12ultra. I picked up the same one in piano black last year!

Mine used to be Rosenut to match the Axiom speaker set, but later I switched over to piano black too .

Now i dont get to use it to often as i live in an basement apartment. But i really got to use it last night and was a bit disappointed. It didnt really seem to put out much boom, but just more low end 30-20hz. I could feel it through the couch but didnt seem to fill the room with much boom?

In the second picture above, the space is huge (looks small in pic), the painting is 25ft away. To the right of the table (behind the TV wall) this is an open kitchen. The right side opens into a lobby and passage to the bedrooms. You can see the sub's placement is far from optimal, but, the PB12U was able to comfortably pressurize the whole space and I never bottomed it out, even when pounding electronic music or loud bass heavy tracks.

How big is your basement? I assume your sub is optimally placed as is your listening position?

It could be that your listening position overlaps with a room mode null in the 60-80Hz region. This is very common for average sized rooms. Alternately, there could be a room mode peak in the 20-30Hz region, at your listening position. This will degrade the qualily of bass due to modal ringing. To rectify the former, move the sub around and for the latter, use the PEQ at the back of the sub to put in a notch filter.

After connecting the pictures to your PMs (big duh! moment), I am guaranteeing that you have room placement issues and possibly the time alignment is incorrectly set, thereby compounding the bass issues.

Kill the PEQ gain till you have the placement and time alignment issues sorted out. It will exacerbate the problems till then. Also, leave Phase knob at 0. Adjusting the distance setting on the Anthem has the same effect as playing with the Phase Setting.

It is critical that you get a visual on the frequency response. Without this, it is impossible to accurately gauge what is going on. The Real Traps website has downloadable test tones and instructions on how to elicit the FR. Please go through this exercise and report back. Until then we are fumbling in the dark.

 

[Hostility]

thank you i was going to bring the pics into this thread. here is the graph from my arc run (this is in the position it is now)
(Bottom right corner)

 

[agarwalro]

Can you also show the Front L, R plots? Also, can you confirm the phase of the sub is at 0 and the distances are accurate in ARC settings? Last but not the least, what are the exact dimensions of the room?

Looking at the subwoofer plot: The dips at approximately 22Hz, 43Hz and 85Hz, I suspect are room mode nulls and most likely the reason you are not getting good bass at your location. (The 7' ceiling is prime suspect.) This is bitter sweet news. You cannot fix them nulls by getting a bigger sub or sealed sub, but, you may be able to address the issue with a second subs.

I would recommend placing the PB12U in the left corner (under the surround) and rerunning ARC just to get measurements. If the dips are at different locations than the plot above, you are golden.