Originally Posted by Ed Mullen
Great post and exactly why we offer both types of subwoofers. It's no secret that within a given family, the ported variant can have 2X, 3X even 4X more output (per CEA-2010) in the 18-36 Hz octave.
No amount of room gain can completely offset this advantage in that octave, and in situations where the room is large/open and lossy - and the customer only wants a single subwoofer - ported is often the best solution simply because of its outstanding output linearity over both octaves (18-36 and 40-80).
With that said, ultimately there is nothing ported can do which sealed can't do better - if the user adds enough sealed subwoofers to overcome the inherent output disparity in the 18-36 Hz octave.
Looking at the worst case data point of 20 Hz, it would take about four (4) SB-2000 Pro to achieve the same output at one (1) PB-2000 Pro at 20 Hz. But four (4) SB-2000 Pro stomp a single PB-2000 Pro everywhere else, and offer a denser standing wave pattern and a smoother FR at more locations in the room and also have the potential (in the right type of room) to extend to 10 Hz or deeper.
Four (4) subs for many customers/users is a total non-starter in most systems - so this is just an example for the sake of this particular discussion.
Thanks, Ed! I hope you already know, that although I was quoting you and Craig, I honestly don't expect to be telling you anything about subwoofers that you don't already know. The reverse, however, would definitely be true. You could certainly tell me things that I don't know. But, I often write posts for the folks who may be reading along silently, many of whom are usually guests, and who couldn't comment even if they wanted to. For that reason, I want to clarify something that I was saying.
I think that the needle has moved significantly in just the last few years with respect to ported subs. When I speak of low-tuned ported subs, I'm not really referring to the octave from 18Hz to 36Hz. Even the PB16, with its 16Hz tune, which I would characterize as a semi-low-tuned ported subwoofer, has a quasi-anechoic max output of 109dB at 16Hz. Most people who buy the larger subs (especially on AVS, which is the group I am really talking about) would buy duals, for a max quasi-anechoic output of 115dB at 16Hz. And, the subwoofers would still remain quite strong down to at least 14Hz, or so, in-room.
But, there are now a number of genuinely low-tuned ID ported subwoofers on the market, and hundreds of them are being sold every quarter. The needle has definitely moved now! Those subs have port tunes varying from 10Hz to about 13-14Hz. Examples are the Rythmik FV18 and the FV25HP. Soon they will be joined by the dual 18" FV28HP's.
Then, there are the PSA TV3612, TV36 iPal, and the TV42 iPal (dual 21" NEO drivers in a very large cabinet, with a 3800 RMS amp). Those subs were just introduced in 2019. Nathan Funk has recently introduced a 24" driver with a 4800 watt amp, in a very large cabinet, along with potential 18" and 21" variants. All of the subs in the last two paragraphs have port tunes in the 11Hz to 14Hz range.
All of them can deliver really serious
SPL down to 12Hz or lower. Several of them can go much lower than that, with room gain augmenting their performance. (As we all know, room gain affects both sealed and ported subs in the same way, as long as there is sufficient SPL at those frequencies to be amplified by room gain.)
And, then there are the JTR ported subs, with their 10Hz port tunes. A single Cap 4000ULF can produce 108dB quasi-anechoically, at 10Hz, and those subs are also most often sold in pairs. Dual Cap 2400ULF's can also produce 108dB quasi-anechoically, and of course, much more than that in-room. And again, they are nearly always sold in pairs. I have a number of AVS friends and acquaintances who have bought those subs.
So, where low-tuned ported subs are concerned, we are no longer talking about the octave between 18Hz and 36Hz. We are seriously talking about the two octaves between 9Hz and 36Hz. Depending on the subs in question, and to some extent on the room volume, dual low-tuned ported subs can legitimately take listeners into good Reference level house curves (rising low-bass) at 10Hz and below. Some listeners can achieve that with just a single large low-tuned ported sub, although for reasons which you understand very well, most of us want dual subs.
In my opinion, this is not just a hypothetical conversation, because on this forum at least, many people are now pursuing very low-frequencies in a way that really wasn't very easy to do at all, even 5 years ago. And, most of the low-tuned ported subwoofer models I listed above have been developed just within the last 3 years.
The curve accelerated exponentially in 2019. PSA alone sold hundreds of the new low-tuned ported subs as soon as they were introduced, with repeated shipments selling-out as soon as they arrived. As I recall, the same thing happened when SVS introduced the new 16 Ultra models in late 2016. As you know, that's when I bought mine. And, Rythmik and Funk both introduced new models, although the Rythmik FV28HP is actually coming in 2020.
There is more demand than ever before for powerful subwoofers, at least on AVS, where people who are really interested in HT may eventually be found. In my experience, most people who upgrade do so in pursuit of lower frequencies, once some basic level of mid-bass performance is achieved.
And, for many people, low-tuned ported subs may be increasingly supplanting sealed subs in the race for very low-frequency performance. The good current crop of low-tuned ported subs can offer at least 115-120dB, quasi-anechoically, for mid-bass frequencies, while beating equivalent sealed subs by very large margins, all the way down to 10-12Hz or even lower. Add in the stronger ULF TR that ported subs can produce within an octave or so of their port tunes, and the combined ULF SPL/TR advantage may become even more pronounced.
Its a very interesting phenomenon, and I have been a little fascinated to watch it unfold over the last few years.