Originally Posted by DarkEnigma
I made a post earlier in this thread about my pb12 plus potentially bottoming out during movies and making a sort of knocking noise. I was told to contact SVS, which i did, although they told me it was difficult to tell what was happening based on the videos i sent. I was told the issue would be escalated and i should expect a response by email, which I never received. I didn't feel like bothering SVS over what seemed to be an issue in only one movie so i let it be. But i watched WarCraft yesterday, since the ultimate list of bass movies thread here recommended it and again while most
of the movie sounded great, I could hear some distracting "flapping" coming from the driver cone area occasionally. I replayed the scene to confirm that it wasn't chuffing that i was hearing. I ran a pb2000 along side it, which was actually
chuffing a bit, but not enough to be audible over everything else playing in that scene, where as the flapping from the pb12 plus was (-10.0 MV on the AVR, -5.0db on subwoofer channel in the avr and -5.0db on the pb12plus itself).
I've also noticed this at high music playback (i play in the -5.0db to 0.0db range, since i like it loud sometimes and i only use 2 channels for music). The pb12 plus will (depending on the song of course) make a flapping noise that is audible over the music. It sounds kind of like a "poof" sound where you'd expect a lot of air to be coming out of the ports but their isn't. From the research I've done, it seems like the 12 plus is hitting it's excursion limits. But why is the pb2000, which seems to have a lot more driver movement than the 12 plus, not making these noises loud enough to be distracting and the 12 plus is?
I'm still within the 45 day trial period so i was honestly considering just returning it, but before i bothered SVS again i figured i'd try here one more time to see if i could get any advice. Faulty sub, or is this something expected when high powered subs are driven hard? I'm a bit of a newbie so i don't know if these are acceptable high drive artifacts from a sub or not (considering the fact that the pb2000, a lesser sub, doesn't do this audibly at my MLP).
The quality of the bass doesn't seem to suffer too much, there just seems to be an annoying "flapping" artifact.
**I should add that turning down the gain on the amp to -8.0db gets rid of the flapping in both the music and WarCraft but does not get rid of the knocking in the old post i made.
Perhaps Ed will read your post and offer some insight into this, but I'm not too sure about the Plus. In theory, it's a more powerful sub than the PB (or PC2000). It's certainly more expensive. But, the 2000 series is a newer design, and it has the advantage of just having the single port tune. The Plus is an older model and is also the lowest model in the SVS food chain to offer variable tuning. And, it seems as if I hear more complaints about that model making bad noises than I do about lower or higher models.
At one time, I had three Pluses in my 6000^3 room, on a concrete slab. (The floor material makes a difference in the amount of tactile response we feel from our subs. Sealed subs are often able to provide perfectly adequate TR on suspended wood floors. Ported subs may be much more helpful for concrete floors.) I had two PC12 Pluses and one PB12 Plus. When I pushed them hard, I could hear them making bad noises. I upgraded to three 13 Ultras, in the same cabinet models, and had no more bad sounds.
I think that you can have ported subs, and enjoy the much more significant low bass and TR they can provide in a large room. But, the ported subs have to be powerful enough to handle what you are asking them to do. My Pluses weren't. My 13 Ultras were.
I would consider one of several options. First, you could return the Plus and get another PB2000. That seems counterintuitive since the Plus should be a better sub. But, as noted above, I'm not entirely sure it is. Second, you could return the Plus and get two PB2000's. Third, you could return the Plus and upgrade the 2000, for dual PB (or PC) 13 Ultra's. I actually like this last solution best, if you are also getting some occasional port chuffing from the 2000. Dual 13 Ultras would take your bass to a different level.
All but the first option involves some additional expense, but that sort of brings us back to the original proposition that ported subs are great as long as you have sufficiently powerful subs for what you are asking them to do. Sealed subs don't generally make any bad noises when they run out of gas, they just stop playing any louder. However, they run out of gas much sooner, below about 50Hz, than ported subs do. And, that is particularly the case if we have large rooms and if we want to hear and feel significant low bass.
Typically, it takes at least two sealed subs, of an equivalent model, to produce as much SPL below about 35Hz as a single ported sub. And, the <35Hz content in movies is what we pay extra for with our subs. So, if you want a lot of low bass, you can have more sealed subs, or fewer ported subs. But, in either case, your subs will have to be powerful enough to satisfy your specific listening objectives without prematurely running out of gas, or making any unpleasant noises.
I hope this helps!