[qazwsx16]

So just finished upgrading our living room theater to a 4.2.4 set-up and absolutely love the outcome. It took about 3 months (due to work and vacation) to finally finish up, but the feeling of getting back to woodworking, drilling, drywall repair, etc. was so enjoyable especially when it all came together. But now I have the feeling to want to do more! I have a few projects I need to take care of in the house for my spouse, but I wanted to start working on some ideas to improve our movie watching experience.

Currently we use our living room for 100% home theater experience and 0% music. This is our current set-up:

• Subwoofer: SVS PB-2000 and SVS PB12-NSD.
• L and R: Two NHT C4s
• Center: Phantom
• Surrounds: Two RSL W25e
• Atmos: Four RSL C34e

I was originally worried that the phantom center wouldn't sound great after I upgraded to a Denon x4400h, but after tinkering with the MultiEQ app, we're pretty content with it now. So the next place that my mind went to were my subwoofers. I was thinking of looking into creating a coffee table subwoofer. The dual benefit of it is: (1) better WAF, (2) I hate our current coffee table, (3) gives me something to work on.

The max dimensions I'm working with: 4 feet wide, 2-3 feet in length, and 18 inches height (including height for feet). The floor below it is laminate with concrete below that (no rugs).

The closest thing I found on the forums was this build here: Coffee table mini marty with RE Audio 18 XX subwoofer

It is a little sparse on details, but the main things I am curious about before I begin doing a deeper dive into this are:

• Are there any issues with a subwoofer being this close to the listening positions? I'm usually at the MLP and my spouse is to my left. We rarely have others over to watch movies.
• From a cost perspective, would this be a worth while upgrade from my current subwoofers?
• From another cost perspective, from others who went through something similar, how much did it cost you for the full project? It looks like in the link above they had used an 18 inch driver.
• If I did this project, would you recommend using this to complement by current subwoofers, or could it replace them altogether? If it could replace them, then I can justify potentially a higher cost!

Please let me know if I can clarify anything!

 

[Kothoga]

The VBSS thread has multiple end tables, not sure about a coffee table. Another option is a sofa table, this Devastator would have more output than 10 of your PB2000s: Devastator BMD Alpha II Narrow 16hz Build

 

[asarose247]

talk to @squiers007
He did a classic build

 

[qazwsx16]

The VBSS thread has multiple end tables, not sure about a coffee table. Another option is a sofa table, this Devastator would have more output than 10 of your PB2000s: Devastator BMD Alpha II Narrow 16hz Build

Oh wow, I wish I had space behind my couch, but unfortunately the gap between the back of the couch and our kitchen island is tight already (image doesn't show it well). But I'll definitely look for the VBSS thread!

@asarose247 I'll reach out to them, thank you!

 

[MalVeauX]

Hi,

No there's not an issue with the sub being this close, it's near field, it can be very handy to have near field depending on what your room is already doing.

The cost perspective is relative. You would need an average to good driver, an amplifier with lots of output, and a DSP. You need building materials, but that's obvious. DIY isn't about saving money, it's about getting more for your money. You will end up spending more on this than a little SVS 2000 sub. But will it be better? Probably will have more extension and output because it will be a larger driver with more power; but how you design it matters, ported vs sealed, vs other.

One sub will not replace your other subs, completely. You need several subs if you want smooth response at all listening positions. One sub will always have a few nulls due to the room dimensions relative to the listening position. You overcome it with multiple subs.

You really should back peddle and ask... what is missing from your current sub-woofer experience? What extension frequency do you feel you need within your working range and at what SPL? What's your room doing, have you measured response at your listening position (REW + calibrated microphone)? What SPL do you listen to (not the -value on your AVR, the actual SPL at your listening position)?

Very best,

 

[18Hurts]

On a side note,

If you are worried about vibration, use either opposed drivers, push-pull drivers or push-pull slot loaded drivers to eliminate vibration. Some people are bothered if their furniture vibrates so if you throw glass on the thing and loose change--using two drivers and a way to keep them in balance would be a good idea.

Enjoy the build.

 

[cnjvh]

Or just put the current subs in the middle of the room and build a table "shell" around it?

 

[clint357]

These are a couple of down-firing subs I built with the Dayton 385 15" drivers. The end table in the top picture is one of two that book-ended my couch. They both sounded pretty amazing for cheap drivers powered by a single iNuke-1000. There were no issues with rattling at normal listening levels but I did have to put some kind of pads on anything that was sitting on them.

 

[jgsabato]

One thing you you should do since you have 2 capable subs, is to move one or both of them to the coffee table position and both listen to them and measure them, and then also do an Audyssey calibration and check again.

Nearfield does not necessarily mean you will get an even response. I tried that with my second sub and the end table position gave good response at 2 of the 3 seats on the couch and a pretty significant null for the third.

Directly behind the center of the couch, with the cone side almost jammed up against it gave the most balanced response at all seats; cone out or pointing to the sides was not that great.

With your 2 subs, you could try cones firing to the sides, cones facing front and back, and with a couple of 2x4's to raise them, face down to simulate a down firing setup. The results of those trials could guide the design and build of your coffee table.

Unlike a lot of people that write in and ask, you are in a position to conceptually test what you want to do before you put a lot of $$ and energy into a DIY project that could end up being a disappointment.

Measure 20 times, Cut once......

One other thing I just thought of for a sub in that position, is depending on where you crossover your mains, they may be some low male voices being reproduced by the sub. Even with a 80Hz 2nd order crossover, you will get voices from the sub drivers at a lower level that could be distracting depending on the orientation of the driver relative to the listener, so include that kind of material while testing. Download "The Summit" by Avi Kaplan for a good test of that possible issue.

 

[MagicTK]

Back in 1999, I had mounted a 18" M&M Godfather car sub that I had, downward facing in the slider door portion of an old coffee table I had (kinda shaped like this). I didn't take time to seal everything, but then I opened up one end as the port, like shown in this quick picture. It faced it away and toward the front corner. It was just experimenting, but it actually sounded pretty good for what it was. I knew if I ever wanted to build one into a table that it would actually work. I never did any box calculation to even know what tuning frequency it was, but it did have a nice low note feel and the carpet was the damping.
HA!

 

[jroadie]

Pretty large open room. I’m surprised you are happy with your current subs. If you’re looking for more bass upgrade subs. If you’re looking for more tactile response then either a near-field sub or some type of BOSS system. I would look at future upgrades, after subs are worked out, of a different LR and add a good center. After you have great bass you’ll probably notice the front sound stage is lacking.

 

[(The Other) Colin Miller]

Subwoofer?

I SAY YES!

 

[(The Other) Colin Miller]

I was originally worried that the phantom center wouldn't sound great after I upgraded to a Denon x4400h, but after tinkering with the MultiEQ app, we're pretty content with it now.

Kind of spinning off on a tangent.

If I have 2 channel content, and I'm sitting all 'centered' up, I don't know that the center (or the surrounds) aren't doing anything.