Originally Posted by Sergey Feingold
I've had a PB-4000 for about a month. For the most part it's incredible although I'm seriously considering trading it for a JTR 2400 if I can get a hold of Jeff...
If I do stick with SVS I'm probably going to upsize to the PB-16. I had an interesting experience tonight that I'd like some thoughts on. I often read that SVS is nigh-on indestructible due to the built in protection. Is this protection exclusive to damage from over-driving (i.e. excursion) or is there thermal overload protection for the driver as well?
I ask because I was watching Logan tonight. Sub is in extended mode, 0dB (-3 in Audyssey) with MV around -10. There's a scene (Xavier in the hotel...) that has some insane bass, and a sustained low rumble for probably over a minute (edit: 3 minutes). If you've seen it you know the scene. It knocked a painting off my neighbor's wall...
Towards the end I noticed an odd smell - the smell of very hot electronics. I'm an electrical engineer and that smell is unmistakable. I didn't see smoke and the sub didn't skip a beat, but pretty clearly either the voice coil or the amp was getting HOT. Despite running the bass at a pretty high volume it was making no weird noises; no odd mechanical sounds, no chuffing. So that brings me to my question: should I be concerned that the sub will self destruct if I run the bass hot in scenes like this? If that scene had gone on another 30 seconds... I have no doubt SVS will take care of it if something dies but I'd like to know the limits all the same.
Anyone had their sub die from sustained bass in movies/music? I was pretty happy with the level of bass that thing was putting out but if this is on the edge and likely to damage something that's all the more reason to upgrade to a more powerful sub.
According to what I have read, there is sometimes a residue of glue on the amplifier, or elsewhere, which can scorch if the subwoofer becomes very hot. That could have been what you smelled if the voice coil appears to be undamaged. In theory, I believe that the limiter and high-pass filter built-into the subwoofer should also provide thermal protection, but I don't think there is anything beyond those to provide specific thermal protection. And, as far as I know, that would be the case with any subwoofer.
Although sustained low-frequency sounds, especially involving sine waves, can damage a voice coil, my guess is that you didn't damage your sub. And, if you did, the warranty would cover it. With that said, I think that with a subwoofer setting of 0, and -3 in Audyssey (potentially also with DEQ engaged which would add another ~4.5db) and a volume of -10 MV, I think you are pushing your single subwoofer right to its limits. The fact that the PB4000 didn't make any bad sounds under those circumstances is a testament to its build quality.
But, my take on this is that if you want to continue to listen at those total bass volumes, you either need another PB4000 or you need to move-up in power. Frankly, I'm not sure that moving-up to a single PB16 would do it. The difference between the two models only averages about 3db below ~ 35Hz. I think you would get more total headroom, across the operating bandwidth, with dual PB4000's.
The subwoofers have approximately the same port tune, so you wouldn't gain any lower extension with the PB16, just more SPL from <35Hz, down to about 14 or 15Hz. (Your room gain would augment the lowest frequencies the subwoofers could play, regardless of the model involved.) And, dual subwoofers of the same model could add 6db, averaged across the full operating bandwidth of the subs.
Long-term, I think that you may be a good candidate for dual subs of whatever model you choose. The JTR Cap 2400ULF would be a good choice, given your affection for loud, low bass. The PSA TV36 iPal would be another excellent choice. That sub has a port tune of about 13.5Hz, rather than the 10Hz port tune of the Cap 2400. But, somewhere around 13 to 15Hz seems to be the sweet spot, for low-tuned ported subs, from every sub maker except Jeff. (Jeff admits that he is more of a niche designer.)
I like the capabilities of the Cap 2400ULF a lot, but I think the new TV36 iPal (which is a slightly larger, more expensive sub) is a better all-around performer. And, the customer service between the two is not comparable. If you do decide to move away from SVS subs, I would also take a hard look at the TV36 iPal. That's an outstanding subwoofer.
It's always tempting to encourage people to stay with the subs you own. I have three PB16's and a nearfield (22") PB4000, in my large room, on concrete. I am very happy with my subwoofers, in every respect, and there is literally no way that I can push them into any kind of distress at all. But, I am also aware of the reality that there are even more powerful subwoofers available, and that I could get equivalent headroom with fewer subwoofers, and less total expense.
When I try to help someone else with subwoofer selections, I think it is important to set aside my own circumstances and preferences and try to address his. Even though this is an SVS thread, that is what I have tried to do here.