[cujobob]

It seems that the implementation is the key, as opposed to the type. The best bass (to my ears and many others) at the RMAF was the servo controlled bass in the GR-Research Super V.  Normally I like the quickness of sealed subs, but the servos make them sound slow.  Also, usually ported speakers are not as clean, but the LS6 and LS9 are both ported line sources that have cleaner bass than any sealed speaker that I've ever heard.

But a sealed ls9 could sound even better although it wouldn't go as low. It's a tradeoff and can't really be compared in such broad terms Imo.

[Rclark]

I plan on trying them all anyway. Since I have these 15's I can try them in various alignments. Speakers will be set for a while but subwoofers can become a fun hobby. Want the most accurate bass possible. I like that ob's will interact with the environment less, like my maggies. Hopefully I can get what I want out of them. I don't even care if the baffle for these has to be huge for low output, Ijust hope it works.

[JohnR]

I plan on trying them all anyway.

Good idea and you're right that it can be fun although sometimes challenging. Placement assisted by measurement will yield the best results.

[S Clark]

But a sealed ls9 could sound even better although it wouldn't go as low. It's a tradeoff and can't really be compared in such broad terms Imo.

You state your premise as an absolute.  One of the key advantages of a large line array is the very low degree of excursion.  I doubt if making it sealed would have significant effect on sound quality.

[johnnycopy]

OB bass when done well is the best at reproducing real bass instruments.  It also excels at seamess integration with any type of midrange.  If you want an awful lot of low bass, buy a more conventional sub. 

If you want OBdone well get a driver purpose built for it.  Hawthorne audio fifteen inch augies on a twenty two inch wide baffle with a big ss amp sound awesome.

I have four of these augies with two rythmik plate amps and i like them better (for the reasons mentioned above) than my velodynes, paradigm or talen rocs that i used to own.

That doesnt mean these more conventional subs cant knock your socks off insome music.

[DS-21]

There's no "better," really. Just the set of tradeoffs that matter to an individual.

Monopole Bass
Sealed:
generally smallest, more tolerant of driver production variance, air spring protects driver to some degree, can pressurize a room below cutoff (stays a monopole), attenuates mechanical noise from driver best (important for extremely long-throw drivers; the only ones I've played with that are dead quiet at long throws are Aurasound's, and they're expensive when they're available) 2d order low-end rolloff makes them easier to integrate with subs (for mains)
BUT
less efficient than anything else listed except for OB, and requires the most excursion for a given output within its passband.

I-B:
same as sealed generally, except invisible in the room and no airspring, BUT sound leakage is a serious (to me disqualifying) issue. Also, one should generally own the structure; renters need not apply.

4th order BP/"front-loaded horn":
more efficient than sealed in the passband, airspring protects driver to some extent, lower distortion because the coupling chamber filters distortion products acoustically, like a closed box stay monopole below cutoff so can pressurize a room down low
BUT
bigger than sealed, larger, upper bandwidth limitations may be an issue with many drivers in many systems (they're generally only good over about 2 octaves), often severe port resonance issues if one uses vents instead of a passive radiator, and they're a lot more sensitive to unit-unit variance in driver parameters.

Hybrid Monopole/Dipole Bass
Vented/"transmission line":
generally larger than sealed (given same woofer), considerably higher efficiency at the bottom of their passband (nearly equivalent to quadrupling amp power), requires lower excursion for a given LF level.
BUT
typical dipole problems down low (don't pressurize a room below cutoff, excursion goes way up below cutoff, leading to overall higher distortion if one doesn't employ a suitable highpass filter), more sensitive to parameter variations than sealed, excursion rises quite a bit just above tuning, pipe resonances from the vents are audible and deleterious (especially with very low tunings)

PR:
vented without the port resonance issues BUT add cost and if they the PR's don't have enough displacement can result in nasty sounds and/or parts destruction

6th order bandpass/"tapped horn"
more efficient than vented systems
BUT
typical dipole issues and larger, severely reduced bandwidth, often massive out-of-band resonances

Dipole bass
often reach similar levels of smoothness in the upper bass with fewer units required than systems that are monopole in that region
BUT
least efficient, placement requirements make them impracticable in many rooms, LF cutoff often quite high.

All that said, the best bass is any one of the above (assuming sufficient bandwidth on the bottom and on the top), with enough of them used (and properly set up, with control each unit's individual level, delay/phase, and arguably though less important than the above, EQ.) Any single bass unit is going to lead to (to me) unacceptable variance in the room's modal region, unless the room is arena-sized.

For me, in a given system the choice will be between multiple sealed, 4th order BP, or PR subs, with the choice between sealed/PR and BP down to size constraints and the choice between sealed/PR based on available driver displacement and amplifier power.
I strongly prefer sealed mains speakers, because they are easiest to integrate with subwoofers.

[johnnycopy]

Post below         

[johnnycopy]

Thats a thorough explanation of the theory behind each type of bass radiating method. 

My shared OB comments are based on real life in-home purchases and experience and as I said, with purpose designed drivers for an OB job. If you haven't used these drivers, expect the limitations mentioned above with OB cause typical drivers are not purpose built to run in free air.  Most people who comment on OB say yeah but they are fully rolled off at 60 hz unless you put them on a baffle the size of a house.  From personal experience, these folks haven't heard Augies (on a 22 inch baffle).

[DS-21]

Thats a thorough explanation of the theory behind each type of bass radiating method.

I hope you didn't think there was any theory in my post! There was simply application thereof to illuminate the actual issues at play. (Most of the "issues" people talk about in the bass are just misinformed nonsense, frankly. And people often seem to think that bass sounds are 1-2 octaves lower than they actually are.)

If you haven't used these drivers, expect the limitations mentioned above with OB cause typical drivers are not purpose built to run in free air.

Funny, Siegfried Linkwitz never felt the need to go with bespoke drivers for the dipoles he designed for Audio Artistry, or for his statement Orion design. Ditto John Kreskovsky, who's designed several open baffle and cardoid bass systems. Of course, what people who have written JAES papers do and what "audiophiles" do... 

From personal experience, these folks haven't heard Augies (on a 22 inch baffle).

There's this great misconception in audiophiledom that some magic part can wish away the inherent physics. It's just not true. I'm sure the Augies more-or-less follow the Bob Carver playbook for OB bass - high Q, low Fs, moderate stroke - and are probably well-optimized for the job. But what actually causes the perceived improvement in the "bass" is actually not low-end extension at all, but big cone area (= less dynamic compression) in the midbass and the upper mids.

That said, for people limited to only having two sound-producing "boxes" in a room, but with relatively few constraints as to placement of those two "boxes," OB probably is the best compromise. The tradeoff - less deep bass but smoother response in the modal region - strikes me as a total no-brainer for someone who loves music more than specs. But a well-executed multisub setup is a great advancement over two OB subs in both the modal region and in the deep bass. And a well-executed multisub system will be visually much less imposing in a room, too. (For instance, I have three subwoofers with a total cabinet volume of 90L in my living room. None are the least bit visible.)

The bottom line is, there's a lot more music in the modal region than in the deep bass. And in the modal region, the room dominates the sound of the system. An OB setup works to limit the room's impact on the sound to some degree, but a multisub system does it better. It doesn't matter if the subs are closed/vented/bandpass, as long as they're sufficient in terms of volume displacement and amp power for the music one enjoys. And not spectacularly misdesigned (either because of variance in driver tolerances or simple incompetence), of course.

[Rclark]

That was the most informative post I've read here on subs. You cleared up quite a lot with that. Thanks!

[BrianAbington]

I really like passive radiators. Great output like a vented enclosure with out the port noise, yet tight and deep like a sealed.

[Æ]

I really like passive radiators. Great output like a vented enclosure with out the port noise, yet tight and deep like a sealed.

A passive radiator is a BASS REFLEX, just a slight variant. Port noise is only a problem when you use the wrong port, wrong size port.

A passive has no tighter or deeper bass than any other reflex design, both are nominally fourth order. However, a passive radiator doesn't leak out nearly as much midrange from inside the enclosure as a port can. Then again a passive radiator has a definite mechanical/acoustical limit, which is just as far as the passive can move (excursion limitations).

Picture of a 6" diameter port.

[BrianAbington]

I understand all that, it's just a personal preference.

[johnnycopy]

There's no "better," really. Just the set of tradeoffs that matter to an individual.

Monopole Bass
Sealed:
generally smallest, more tolerant of driver production variance, air spring protects driver to some degree, can pressurize a room below cutoff (stays a monopole), attenuates mechanical noise from driver best (important for extremely long-throw drivers; the only ones I've played with that are dead quiet at long throws are Aurasound's, and they're expensive when they're available) 2d order low-end rolloff makes them easier to integrate with subs (for mains)
BUT
less efficient than anything else listed except for OB, and requires the most excursion for a given output within its passband.

I-B:
same as sealed generally, except invisible in the room and no airspring, BUT sound leakage is a serious (to me disqualifying) issue. Also, one should generally own the structure; renters need not apply.

4th order BP/"front-loaded horn":
more efficient than sealed in the passband, airspring protects driver to some extent, lower distortion because the coupling chamber filters distortion products acoustically, like a closed box stay monopole below cutoff so can pressurize a room down low
BUT
bigger than sealed, larger, upper bandwidth limitations may be an issue with many drivers in many systems (they're generally only good over about 2 octaves), often severe port resonance issues if one uses vents instead of a passive radiator, and they're a lot more sensitive to unit-unit variance in driver parameters.

Hybrid Monopole/Dipole Bass
Vented/"transmission line":
generally larger than sealed (given same woofer), considerably higher efficiency at the bottom of their passband (nearly equivalent to quadrupling amp power), requires lower excursion for a given LF level.
BUT
typical dipole problems down low (don't pressurize a room below cutoff, excursion goes way up below cutoff, leading to overall higher distortion if one doesn't employ a suitable highpass filter), more sensitive to parameter variations than sealed, excursion rises quite a bit just above tuning, pipe resonances from the vents are audible and deleterious (especially with very low tunings)

PR:
vented without the port resonance issues BUT add cost and if they the PR's don't have enough displacement can result in nasty sounds and/or parts destruction

6th order bandpass/"tapped horn"
more efficient than vented systems
BUT
typical dipole issues and larger, severely reduced bandwidth, often massive out-of-band resonances

Dipole bass
often reach similar levels of smoothness in the upper bass with fewer units required than systems that are monopole in that region
BUT
least efficient, placement requirements make them impracticable in many rooms, LF cutoff often quite high.

All that said, the best bass is any one of the above (assuming sufficient bandwidth on the bottom and on the top), with enough of them used (and properly set up, with control each unit's individual level, delay/phase, and arguably though less important than the above, EQ.) Any single bass unit is going to lead to (to me) unacceptable variance in the room's modal region, unless the room is arena-sized.

For me, in a given system the choice will be between multiple sealed, 4th order BP, or PR subs, with the choice between sealed/PR and BP down to size constraints and the choice between sealed/PR based on available driver displacement and amplifier power.
I strongly prefer sealed mains speakers, because they are easiest to integrate with subwoofers.

My reply relates to your last sentence.

My starting point is the mains, and there i have liked quads, dayton wrights, magnepans, scintillas, accoustat, martin logan, newform research, etc.  And  now hawthorne audio. Many of these manufacturers tried to integrate their excellent mid and upper range drivers with conventional sealed woofers. i have never felt satisfied with the bass integration on these setups.  OB bass, however i have found, does integrate more successfully, and to me is more musical.

I'm sure there are alot of competent OB drivers out there, I've only heard the Hawthorne. But I've read from alot of folks online that OB doesn't do decent bass, and then I see pictures of drivers stuck to 5 foot wide baffles, and it tells me other's are experiencing a whole bunch of limitations as they attempt to try OB that I've not had to deal with.   

Many individual tastes and many types of music to satisfy those tastes. For me it's OB at this point in my audio journey, not saying I don't like the rest, just my personal preference.

[JohnR]

But a well-executed multisub setup is a great advancement over two OB subs in both the modal region and in the deep bass.

Do you have measurements of your setup?

[Æ]

Do you have measurements of your setup?

I agree with him too.

[JLM]

I've heard a few O.B. variants and somehow all of the Hawthorne's have bass with almost no baffle (the Augie adds more "feel" than sound and is barely needed for music).  At the 2009 AKFest the Augies were there but not running (while I was there).  There were only 3 rooms that had decent/good bass in those small rooms, GINI and Fried (both transmission line designs) and the Hawthorne Sterling Silver 15 inchers. 

With their prices, DIY/manufactured options, efficiency, professional build quality, and small baffle requirements Hawthornes should be everyone's first thought for O.B.

Note that other transmission line and O.B. designs were there, but they like all the other fullrangers exhibited "room boom".

[DS-21]

Do you have measurements of your setup?

Here's the final tweaked version of my old (~last May) modest (1x DIY sub based on the Peerless Application Note with a Dayton SA240 pushing a Peerless XLS12 and PR, and two KEF HTB2's) multisub setup, with level, delay/phase, and parametric EQ all from an unbalanced miniDSP-in-a-Box. (The HTB2 is a good-looking and a surprisingly good-performer within its design limits, but lacks any controls on the unit, not even level. So using them required an external box.) Measurement is a five-point spatial average, taken from a Velodyne SMS-1/MIC-5 combo.

 

I plan to get better measurements for the new, totally concealed setup - all DIY and all closed boxes, with the main sub being an Aurasound NS12-794-4A in 65L, the second sub an Aurasound NS10-794-4A in 15L, and the third a Peerless XLS10 in 10L, but my old MacBook's screen died, and turns out the new one doesn't have a FireWire Port, so I can't use my M-Audio FireWire Solo/FuzzMeasure rig. I do have an Art Dual Pre on order so I can measure things with the new MacBook. Also, I've been having amp trouble, or more specifically miniDSP-amp interface troubles, because of the miniDSP's low output. It couldn't drive the NHT A1's I wanted to use for the Aurasound subs - the Peerless sub has a plate amp - satisfactorily, and I had some noise issues with a Peavey IPR-3000 as well. I'm thinking about getting a second Dayton SA-1000 (even though it's total overkill) because I know they work well on the weak outputs of the miniDSP.

Here's one of my first multisub setups, ca. 2005, with no EQ at all!. Just individual levels/phase. I don't quite remember the subs used. I think they were a Tannoy B475 in the corner, and two DIY sub with a JBL 2235H each. The secondary subs may have been Peerless XLS12's with PR's, but looking at the low-end extension of the system I don't think so.

[johnnycopy]

I've heard a few O.B. variants and somehow all of the Hawthorne's have bass with almost no baffle (the Augie adds more "feel" than sound and is barely needed for music).  At the 2009 AKFest the Augies were there but not running (while I was there).  There were only 3 rooms that had decent/good bass in those small rooms, GINI and Fried (both transmission line designs) and the Hawthorne Sterling Silver 15 inchers. 

With their prices, DIY/manufactured options, efficiency, professional build quality, and small baffle requirements Hawthornes should be everyone's first thought for O.B.
 
Note that other transmission line and O.B. designs were there, but they like all the other fullrangers exhibited "room boom"

Certainly agree, glad to hear others who have actually heard hawthorne products confirm my personal experience with  the unique  characteristics of these OB drivers.

[Rclark]

You guys should look up pics of BobinStLouis's system. He's running those exact drivers and his system looks awesome.