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Sealed bass
In your opinions, how low must a sealed alignment extend to "compete" with ported alignments? In the past, I have found sealed bass at or below 60hz to be very satisfying but somehow I generally end up enjoying ported bass even more.
I have a quad of Eclipse 6.5" 8 ohm that have a Q of ~0.55 so perfect for either a large vented enclosure (4 cubic feet/pr lol, but 28Hz F3 is nothing to sneeze at) or in 1.5 cubes/pr sealed they model to the very low 50s.
Just pondering on a new design that will be similar to the Taiga build I did a decade ago. That design used a pair of the 4 ohm Eclipse wired in series per side, a CSS VWR (I think, a 4.5" with a copper dustcap) and an OG Viawave tweeter. It is not my intention to replace them, as they are the wifes favorite speakers - but I think mating these 8 ohm Eclipse with one of those SB/Aerial buyout 4" mids and a GRS ribbon tweeter would be a pretty nice midsize tower. It would help me consume inventory, thats for sure.
Anyways, thoughts on sealed vs ported? Age old question, I know.
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In my limited experience, the room modes and location of the woofer make the biggest difference, JR.
I've been just modeling for the smoothest roll-off and lowest Group Delay in my cabinet sizes of late and still find the [ported] bass overpowering in-room [basement studio] compared to my shop building [larger space].
See that sock stuffed in there? . . .
Speaker is up against the front wall:
Acoustas DSP Amp settings for sealed bass concerning the above response [hope it is germane]:
For me I've been leaning towards preferring sealed over ported for its smoother and controlled rolloff, could be my room and/or my less than perfect ported woofer builds (and many I've listened to) have that 1 note cliff sense. I did find the partial sock port method with my single Eclipse worked wonders (high tech tuning method- ha).
I have 4 of the GRS 12" subs in my room. I started out ported with an f3 of 20hz, and they never sounded that great in my room. I switched them over to sealed and got an f3 just under 40 hz. I added 10db of boost at 20hz, and they sound incredible now. Granted I only run subs in my system up to 35hz, and let me mains run full steam, but that is the only integration I have found that I can live with. If I design my mains to play down to the low 40s, I get enough room gain where my subs meet up nicely. I know this is nowhere near your scenario, but I was surprised at the outcome. As for my mains, my room needs a bit of a boost in the bass for me to be satisfied. I would like to try a sealed set of mains at some point to see if I like it or not.
You can easily have too large of a subwoofer(s) for the space and vice versa . . . hard to tame that - even with DSP . . .
If I find a woofer can go down to the 50 sealed, it can usually do 30's ported. But the box is usually much smaller. If there's generous Xmax, getting selaed to 30's form 50's with DSP sacrifices only a few Db's from the max SPL (usually over 100 db's), but saves a bunch of headaches such as loooong ports, chuffing or added cost of PRs. So somehting goes to 50's I prefer sealed, but sometimes a tiny driver will extend to below 30's then ported on a desktop at normal volume has it's own charm (but not at 4 cu ft! - I would go sealed with a 15" Sub)
Problem is, most woofers available today are not designed for sealed acoustic suspension with significant, deep bass output. Except, maybe, for some of the Human Speakers brand, but I have not ordered any of these yet. Correct me if I am wrong, but back in the 70's & 80's Advent and Acoustic Research developed several sealed type acoustic suspension designs that targeted an in box Fc in the lower 40's using long throw woofers with T/S parameters specifically designed for deep bass extension in a relative small box (1.5 cu.ft.) These speakers could dig deep and were very competitive with the low frequency extension currently available with most of today's bass reflex designs. And they sounded much cleaner than bass reflex designs with open ports. I much prefer the sound of a good sealed design. But speakers with T/S parameters for deep, sealed bass extension are not available today.
Here is a link to the Human Speakers 10" woofer that is said to be a replacement for the original Large Advent Loudspeaker woofer. Problem is, the xmax is listed as only 0.25 inches (6.5mm).
https://www.humanspeakers.com/diy/parts/031.htm
RSS210HF 8in 4ohm, stated 41Hz in sealed 0.9cu ft
A couple of years ago I was planning to build a monkey coffin 3 way with a 10 or 12 inch woofer, possibly with a capacitor boost.
Bought a pair of the PE UM12-22 woofers, and they modeled very nicely in a 1.5ft^3 sealed box - F3 at 33Hz, F6 at 27Hz , even without the capacitor boost. Modeled with 300W power, never got close to exceeding Xmax. I may still build those.....
Having built many ported designs, I am leaning towards sealed these days. It may have something to due with ported woofers unloading below Fb, or it may be interaction with room boost.
Yeah, but in 1ft^3 ported to 30Hz, stuffed with 1.5 pounds of fill, they yield an F3/10 of 26/19Hz. It indeed sounds awesome too!
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I have some Peerless 830668 paper cone 10" drivers that I want to try in sealed enclosures for a 3 way. Maybe with aperiodic vents. Modeled F3 is only 44 Hz, but with that 12 dB/octave roll off and room gain maybe pretty sweet! I have the perfect (buyout) 4" mids to go with them! Maybe even break my new rule and buy some of those GRS ribbon tweeters.
I have found that the difference is about 1/2 octave subjectively. So 40hz sealed sounds as extended as 30hz ported as an example. Just my opinion.
In my room (19L x 13W x 8H) using one of the early version RSS315HF - sealed for sure. I believe that driver had an F3 in the high 30's. I have boost available, but I don't use it. It seems to go down forever . . . I've always preferred sealed in a car as well, FWIW.
Never overlook the effects of baffle step loss when compairing box models, sometimes that slow roll off looks a little better after BSC. I also find it much easier to use room correction on sealed systems.
Here’s two 12” woofers designed for sealed boxes:
Peerless 12” XXLS 8 ohm pulp cone
(830845) ; works well in 2 cu ft sealed
Measurement here:
https://www.diyaudio.com/community/threads/a-clean-12-woofer-peerless-by-tymphany-xxls-p830845.426061/post-7977637
Peerless 12” XXLS 4 ohm alu cone
(835017); works well in 1 cu ft sealed:
Measurements here:
https://www.diyaudio.com/community/threads/a-clean-12-woofer-peerless-by-tymphany-xxls-p830845.426061/post-7982311
In-room bass response matters a lot; I’ve also had very pleasant experiences with ported bass alignments. One day I want to try 6th order series tuned bandpass, or tapped horn alignments, for more bass per $ of woofer.
Are we assuming no EQ with the question? Personally I haven’t built a ported speaker since the OG miniDSP 2x4 came out. I’ve also found that room modes dictate extension at least as much as the alignment. So simple closed box with in situ EQ is IMO the path of least resistance.
I think ported and sealed can be satisfying in different ways, but for most "regular" speakers, the difference ends up being a lot of energy in the 30-50Hz range, which I find I really miss on a lot of tracks if its not there. If I go sealed, lately I've been finding Qtc has to be 0.9 minimum or it just lacks too much punch. My latest sealed build has F3 = 45Hz and Qtc = 0.9 and it sounds great, but on some tracks I miss the 33Hz F3 ported bass on the pair next to them.
I like to hear just a light hint of super low stuff. Gives a whiff of something lurking deeper. Most subs I've had just kindof overdo it so I often rather go without. One of my favorite little subs was on an old Logitech 2.1 pc speaker system. I thought it was an 8" sealed sub. But found out it actually is something like a 4" woofer, 4th order bandpass with an 8" PR. Something about it seemed so musical.
Gotta love those PR-bandpasses!
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I had that system for awhile back in the day.
I did too. It was really impressive.
I think you’d find what you’re looking for on the car audio side of the hobby. Due to the space constraints there were/are some manufacturers with low Q/low Fs drivers and decent throw
Do you have a link to any of these drivers? The original Advent masonite woofers had an Fs of about 18Hz or so. Qts was about .35 as I recall. Vas was fairly high, however, because the cone was about 9 inches in diameter and the magnet was fairly small.
https://community.classicspeakerpages.net/topic/5162-large-advent-specs/
What physical attributes would make low Fs and low Q like that?
Heavy cone, loose suspension, and powerful motor.
Efficiency, what's that?
I should add VC gap also contributes heavily to driver Q.
Ah, I imagine that is a direct factor in motor force. Closer proximity concentrates more flux. I bet that gets real dicy when designing with a loose suspension.