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Sealed Subwoofer Nearfield Low Bass

3545 Views 5 Replies 5 Participants Last post by  sdurani

I recently got two SVS SB3000 subwoofers to pair with my KEF LS50 Wireless system. I'm using the sub out from the LS50W using a Y-splitter to connect the two subs. They are crossed in at 80Hz directly form the KEF app and Low Pass is set to off in the SVS app.

Now I have an issue of uneven bass in the room due to cancellations (even when I went with dual subs) and I get that, but my problem is not there I think. With everything adjusted, the subs sound PHENOMENAL! No complaints there! The SVS Soundpath Isolation Systems are on their way to get rid of some rattling in my room. The main problem is the lack of bass (especially the lower notes) in my room when I'm sitting close to the subs. I have attached a diagram of my room so that it's easier for people to understand the situation. The PDF file shows the room layout and the Photo files show the perspective views at the direction as shown in the diagram (Labelled A, B, C, D, E). Also please excuse the hellish mess in my room :(

I have played with the Phase Adjustments in the SVS app, Parametric EQ, etc with no success. The bass is awesome on my bed and near the area near to the opposing wall to the subs, with great texture, slam and tactile response. As I move closer to the subs, the bass decreases significantly, especially the low bass. To compensate I increase the gain of the subs but then the subs just get louder and the low notes are still missing. But now the bass on my bed is overwhelming and muddies the sound greatly. I have marked these two spots in the PDF diagram with boxed outlines.

No matter what I cannot get the awesome bass I experience nearfield which I get at the other end of the room. The difference is always there (Bed=Awesome, Nearfield=Underwhelming/Nearfield=Good, Bed= Overwhelming). I have adjusted Room Gain Compensation in the SVS app and it makes an audible difference near the bed but no difference nearfield. It's as if nearfield there is a High Pass working for the subs at around 60 Hz.

Is there a solution to this or is it just the basic characteristics of these subs and I just have to live with it? Prior to the SB3000s I had a single JBL Stage 120P subwoofer with rear firing ports in the exact spot as the right SB3000 now and the bass was more even. Nearfield I was getting low bass as well maybe because of the ports firing towards the rear wall? The SB3000s are tighter and has all the perks of a sealed sub but is this the drawback of sealed subs?

Anyone please feel free to offer some advice because I'm desperate! I don't even want to believe that a $350 dollar sub would serve my purpose better than a $2000 setup.


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It can be challenging setting up bass to sound its best in different seating positions. You really need to decide where your going to listen to your sound system most (your primary listening position) and tune it accordingly to that position. I know aesthetically you like where your subs are located but more than likely they are not in the best location in your room. Not every location in a room will sound the same, just doesn't work that way as the room/MLP/sub(s) location will dictate that.

It is notorious to have boomy bass if listening position is against a back wall from the front sound stage,,, this is what your experiencing imo. If your not interested in REW and taking measurements then (based on your MLP) a sub crawl can help. At the very least i'd try and move your subs to the outside of your Kefs,,,, and not make you beds headboard the MLP.
I really may know the solution to this. Besides attempting the adjustment of phase in one of the 3000’s, and besides trying out the room gain compensation set to on and at 31hz with a -6db slope (instead of the default 12db), there is one thing that I personally have tried and I too sir near field and it was amazing the difference it made.

I’m lucky I seem have a lot of extra equipment because I make terrible choices and hate to take more than a 50% loss for them if trying to resell, so I have a second pair of Dynaudio stand 10 speaker stands and I have the special order Dynaudio contour top plates attached to the stands instead of the small default top plates. This equates to a top plate that is 14 inches deep versus the stand10’s top plate which is like 6 inches deep or something.

Anyways I took off the little pathetic rubber cone feet off my sb-3000 (I have two by the way but I tried this experiment with just one subwoofer). I placed four isoacoustics iso-pucks (the full size ones not the minis), made sure the logo was facing the forward position so the recoil axis would be aligned with the subwoofers front firing woofer, then placed the sb-3000 on top.

This was located just in between the receiver / power amp / equipment rack/ center channel and the front left speaker. It looked real ugly and out of place. Almost looked like a giant Star Wars tie fighter sitting in my living room. Anyhow, once playing music the bass was full and sounded great and I actually was able to turn down the subwoofer level from the usual 15-18 down to 20-22 and it sounded impactful and balanced still.

TLDR: raise your subwoofer off the floor by at least 18 inches. My stands/pucks raised it 25-26 inches and sounded amazing. Stands were filled with sand to almost 100% capacity which is not recommended but I found out too late and am too lazy to empty it to 50%.

Room dimensions 15ft long (speakers firing down this way) x 11.7 feet wide

Hope this helps.

Oh almost forgot. I’ve been getting better results when I angle my left subwoofer 45 degrees so it’s rear is facing the corner then keep the right sub facing straight and then I only adjust the phase on the left sub that’s angled, usually using 50-60 or 120-135 degrees of phase setting.

I haven’t tried raising the sub and angling it yet but i should. If you ever do let me know how it works out for you.
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Just saw your pictures and noticed your setup seems to be on the longer wall and firing down the short wall. I am not saying it’s impossible but I had it setup like this before in my living room and no matter what I did I could not get it to sound “right” or balanced. When I added a Larger sub, this exasperated the effect. Only thing that helped was facing the subwoofers to the left and right, but even so, my small 8” down firing subwoofer at the time trounced the larger subs when the larger subs individually cost over twice the 8” downfiring one.
Your only solution is to move one or both of the subs and keep moving them until you get what you want when on the bed. As previously stated. where they look good is usually not where they sound good. Here are some typical solutions to try out:


Also, please understand that the seating position is just as important as the sub positions. If the head of your bed is in a null (certainly sounds like that's the case), then moving the bed may help to solve the problem, if moving the subs does not.

Multiple sub placement is hard. Some rooms are a lot harder than others. Persistence AND flexibility is required. Keep at it!
The main problem is the lack of bass (especially the lower notes) in my room when I'm sitting close to the subs.
By "close to the subs" do you mean near the foot of your bed? If so, you're sitting in a large 38Hz null at the midpoint of room length. This same location has a 75Hz peak. Both problems together will give the impression of a lack of bass in the lower notes.
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