Can you have too much?

[shadyJ]

Those look nice but ULS15 and VTF15 are pretty close in price esp since his budget is much higher. Seems like ported would be a good choice in his den where WAF should not be part of the equation. What are your thoughts on sealed subs? Do you prefer sealed? I have a sealed sub in my bedroom system, a Rythmik L12 and it isn’t prefect but it performs well in 1400 cu ft. My current thinking is I don’t really see an advantage to a sealed design when a ported sub can produce higher output.

There is one advantage that sealed can have in performance. Typical sealed low-end rolloffs are gradual, and this enables them to better take advantage of room gain when it can be had. In a small, sealed room, a sealed subwoofer can still manage some low-frequency output that isn't overly boosted in the low end. Ported subs have a sudden rolloff that won't benefit from gain as much, and where it does benefit, it can get too much of a boost since they can be made to have a flat response down to low frequencies. Some ported subs have ways of tempering their low end though, where there can be too much room gain that produces unnaturally boosted deep bass. SVS has their Room Gain Compensation setting, as well as a parametric equalizer. On top of that, you can run their variable tuned subs in a sealed mode. Hsu has their Q control, and also the ability to run in sealed mode. Other subs have similar features.

 

[Steve81]

Seems like ported would be a good choice in his den where WAF should not be part of the equation. What are your thoughts on sealed subs? Do you prefer sealed? I have a sealed sub in my bedroom system, a Rythmik L12 and it isn’t prefect but it performs well in 1400 cu ft. My current thinking is I don’t really see an advantage to a sealed design when a ported sub can produce higher output.

To be clear, I've got nothing against ported subs. I think the FV18, Monoprice, VTF15, et al. would do just fine in Ryan's new 2000cf space.

OTOH, as James noted above, given their relatively flat response outdoors, in a real room (and particularly in smaller spaces) those subs can get bottom heavy due to cabin gain. While EQ can solve that problem easily enough, I prefer aiming to get a sub whose low end response matches up reasonably well with the room its going in. Seems more elegant to me vs getting a big ported box with the foreknowledge that you're probably going to have to pad down output in the bandwidth where the port is doing its business.

Of course, there are other advantages to consider as well. Extension into the single digits has been mentioned, and is viable contingent upon cabin gain and enough subwoofage to make it meaningful. Beyond that, there are no ports to chuff or compress. The latter is something that tends to get overlooked in comparisons that focus solely on max output. Consider the case of the JTR Cap 1400 vs the S2. At 16Hz, the CEA charts rate the ported Cap 1400 as the champ. Looking at the long term sweeps and the compression figures tell another story:



Looking at the Cap 1400 first, it's clear that the port is progressively compressing from the 95dB sweep on up, even as it continues on to deliver over 108dB @ 16Hz. Conversely, the S2 exhibits negligible compression on the low end until the system finally runs out of gas. That's an important difference, and one area where CEA burst testing doesn't reflect the reality of how we use our systems. We aren't running bursts at progressively increasing levels till our subs beg for mercy. We're calibrating them to deliver a particular response, setting a master volume level on our AVR or pre/pro, and letting our choice of content do the rest. Compression is a problem there because it means we aren't getting the output we expect from calibrating our equipment, and it's not something we can readily resolve with EQ.

 

[snakeeyes]

To be clear, I've got nothing against ported subs. I think the FV18, Monoprice, VTF15, et al. would do just fine in Ryan's new 2000cf space.

OTOH, as James noted above, given their relatively flat response outdoors, in a real room (and particularly in smaller spaces) those subs can get bottom heavy due to cabin gain. While EQ can solve that problem easily enough, I prefer aiming to get a sub whose low end response matches up reasonably well with the room its going in. Seems more elegant to me vs getting a big ported box with the foreknowledge that you're probably going to have to pad down output in the bandwidth where the port is doing its business.

Of course, there are other advantages to consider as well. Extension into the single digits has been mentioned, and is viable contingent upon cabin gain and enough subwoofage to make it meaningful. Beyond that, there are no ports to chuff or compress. The latter is something that tends to get overlooked in comparisons that focus solely on max output. Consider the case of the JTR Cap 1400 vs the S2. At 16Hz, the CEA charts rate the ported Cap 1400 as the champ. Looking at the long term sweeps and the compression figures tell another story:

View attachment 26489View attachment 26490

Looking at the Cap 1400 first, it's clear that the port is progressively compressing from the 95dB sweep on up, even as it continues on to deliver over 108dB @ 16Hz. Conversely, the S2 exhibits negligible compression on the low end until the system finally runs out of gas. That's an important difference, and one area where CEA burst testing doesn't reflect the reality of how we use our systems. We aren't running bursts at progressively increasing levels till our subs beg for mercy. We're calibrating them to deliver a particular response, setting a master volume level on our AVR or pre/pro, and letting our choice of content do the rest. Compression is a problem there because it means we aren't getting the output we expect from calibrating our equipment, and it's not something we can readily resolve with EQ.

Ok a lot to digest there. What size sealed room is a “smaller space” appropriate for sealed subs? Less than 3000 cu ft?

 

[lovinthehd]

Widening the flares of the port may reduce chuffing and make for a bit smoother port behavior at low frequencies. However, I remember reading a JBL white paper that said it was the shape of the port, not the flaring, which is what is effective in reducing chuffing. I am seeing more port designs that uses the port shape described in the JBL paper.

Seems BIC also made a bit of a deal about a flared port. In thinking about the math can't think a flared port at one end makes much difference...

 

[Steve81]

What size sealed room is a “smaller space” appropriate for sealed subs? Less than 3000 cu ft?

It’s hard to qualify given that not all rooms are created equally, nor are sealed subs for that matter. And of course budgets and goals matter too.

 

[Danzilla31]

Not to mention (again ) the price. The way I see it, try two. If they do the trick, great, and he's got a couple of subs that look decent, take up minimal space, and came in well under budget. If he yearns for more, get another pair. If that's not enough in 2000 cubic feet, he needs Bassaholics Anonymous.

There's no such thing as Bassaholics Anonymous I'm not in denial. AT ALL. I don't need to much Bass. I don't need multiples of subs. Matter of fact I could sell one of my extra subs off no problem. I am in complete control here.

 

[Danzilla31]

To be clear, I've got nothing against ported subs. I think the FV18, Monoprice, VTF15, et al. would do just fine in Ryan's new 2000cf space.

OTOH, as James noted above, given their relatively flat response outdoors, in a real room (and particularly in smaller spaces) those subs can get bottom heavy due to cabin gain. While EQ can solve that problem easily enough, I prefer aiming to get a sub whose low end response matches up reasonably well with the room its going in. Seems more elegant to me vs getting a big ported box with the foreknowledge that you're probably going to have to pad down output in the bandwidth where the port is doing its business.

Of course, there are other advantages to consider as well. Extension into the single digits has been mentioned, and is viable contingent upon cabin gain and enough subwoofage to make it meaningful. Beyond that, there are no ports to chuff or compress. The latter is something that tends to get overlooked in comparisons that focus solely on max output. Consider the case of the JTR Cap 1400 vs the S2. At 16Hz, the CEA charts rate the ported Cap 1400 as the champ. Looking at the long term sweeps and the compression figures tell another story:

View attachment 26489View attachment 26490

Looking at the Cap 1400 first, it's clear that the port is progressively compressing from the 95dB sweep on up, even as it continues on to deliver over 108dB @ 16Hz. Conversely, the S2 exhibits negligible compression on the low end until the system finally runs out of gas. That's an important difference, and one area where CEA burst testing doesn't reflect the reality of how we use our systems. We aren't running bursts at progressively increasing levels till our subs beg for mercy. We're calibrating them to deliver a particular response, setting a master volume level on our AVR or pre/pro, and letting our choice of content do the rest. Compression is a problem there because it means we aren't getting the output we expect from calibrating our equipment, and it's not something we can readily resolve with EQ.

I totally agree with everything your saying it's just man it seems like to get any decent low end sealed sub it gets crazy crazy expensive. Or you gotta get so many that it's just unfeasible for fellas like me that got to set up in there living room. I don't even want to think what Id have to buy or get to do any damage down low in my big big living area that would be a sealed sub. That part of it just feels frustrating

 

[snakeeyes]

There's no such thing as Bassaholics Anonymous I'm not in denial. AT ALL. I don't need to much Bass. I don't need multiples of subs. Matter of fact I could sell one of my extra subs off no problem. I am in complete control here.

Ya like Golem and his precious. LOL

 

[snakeeyes]

It’s hard to qualify given that not all rooms are created equally, nor are sealed subs for that matter. And of course budgets and goals matter too.

I’m a couple years away from sub upgrades in my 2600 cu ft sealed room but sealed vs ported will be interesting. Of course with HSU you can change between ported and sealed on the VTF series so that’s a likely option.

 

[ryanosaur]

Not to mention (again ) the price. The way I see it, try two. If they do the trick, great, and he's got a couple of subs that look decent, take up minimal space, and came in well under budget. If he yearns for more, get another pair. If that's not enough in 2000 cubic feet, he needs Bassaholics Anonymous.

No... I need 4 Funk subs!

 

[ryanosaur]

Ok... been trying to learn more about sub performance, and I guess where i'm getting stumped is understanding and interpreting the potential output from a sub. Might you guys help me with that, please?

 

[shadyJ]

Ok... been trying to learn more about sub performance, and I guess where i'm getting stumped is understanding and interpreting the potential output from a sub. Might you guys help me with that, please?

What do you want to know specifically?

 

[ryanosaur]

I feel like i'm missing something obvious in knowing what SPL a sub can create/output. I'm certain some of this is my inexperience (all), It's not about how loud I can push it, but like I said at the beginning, I want the option of hitting that refernce level on occasion.
Is it in the specs? and if so, how is it reported?
If not there, than test charts? I recall a max output graph on Data Bass, but I don't see those anywhere else that I recall.
And then there are the CEA test charts. (spl you want high; thd, low... what is the harmonic limit representing?) (Just using the X-13 review from here... you, Shady?... cos' I had it open in another tab.)
Is this where I need to be looking?

 

[Steve81]

I feel like i'm missing something obvious in knowing what SPL a sub can create/output. I'm certain some of this is my inexperience (all), It's not about how loud I can push it, but like I said at the beginning, I want the option of hitting that refernce level on occasion.

It's complicated, but I'll keep things as simple as possible.

1. There isn't anything on a spec sheet that will tell you how loud a subwoofer will get at the seats in your specific room. It's not possible with any degree of accuracy.

2. Reference level is a bitch. With the LFE channel plus redirected bass, a subwoofer(s) can be asked to reproduce over 120dB at the seats in a worst case scenario, with significant content potentially well below 20 or 16Hz.

3. In spite of 1 and 2, there are some guidelines out there. You know about the AH room rating protocol, so I won't rehash that. There are also the THX certifications, with the Ultra in particular being geared towards 3000 cubic foot theaters. Will a THX Ultra subwoofer deliver 120+dB at 20Hz at your seats? Heck no. Instead, THX has analyzed a wide range of movies to come up with a halfway realistic specification for what it would take to do a competent job with reference level reproduction. Looking at something like the Monolith 12 measurements would give you a fair idea of what they expect is required, and you can compare those measurements with various other subs.

 

[TechHDS]

The cone composition isn't necessarily going to help. If they switched to aluminum for the LVX12, that would make the driver heavier which would reduce its mid bass headroom. You would need to have real changes made to the motor and suspension as well. The LVX12 is banking on its larger cabinet for extra efficiency. I believe its using the same driver as the other budget 12"s. My guess is that enclosure is optimized for that driver. You could put a more powerful driver in that cabinet, but I doubt that would be optimal. For example, how would the vent flow handle that extra displacement?

So long as you have the same amount of displacement in room, the headroom will remain the same. You are dumping the same amount of energy in the room whether you bunch the subwoofers all in one spot or spread them out. The idea that placing them all in one spot makes them louder is a misunderstanding. It only makes everything louder for the specific response which that location engenders.

Well Shady J So far I’ve found out that My Impression Elite Speakers have the wrong size Connectors - Black on all of the drivers. One was Completely off on the mid driver below the Tweeter on my left front main. So stay tuned. When I’m done with the right front main speaker cause Daren over at RBH. ask me to Crimp down on the negative terminal Connectors on both Towers and I haven’t even checked out the center speaker yet, so I may need your Skills, so loose I didn’t need to even use my tool set, now the + red has the right size Connector it is very tight I’m just about done with the right Tower soo stay tuned Guys! I may be needing some of that Expertise you guys have

Mike

 

[TechHDS]

I just found out that loose speaker Connectors at the speaker driver can and will change ohms at the XO. So Steve’s review on the ohms of the Elite Towers Actually was closer the 4.86 something if I remember right? What the Possibility of the ohms Changing day drop below 4 ohms Or got above the that. RBH has them rated @ 6 Ohms.

 

[Danzilla31]

Widening the flares of the port may reduce chuffing and make for a bit smoother port behavior at low frequencies. However, I remember reading a JBL white paper that said it was the shape of the port, not the flaring, which is what is effective in reducing chuffing. I am seeing more port designs that uses the port shape described in the JBL paper.

Hey what shape did they say helps reduce chuffing the most? I wonder if it's those slotted ports like the Captivators have

 

[ryanosaur]

It's complicated, but I'll keep things as simple as possible.

1. There isn't anything on a spec sheet that will tell you how loud a subwoofer will get at the seats in your specific room. It's not possible with any degree of accuracy.

2. Reference level is a bitch. With the LFE channel plus redirected bass, a subwoofer(s) can be asked to reproduce over 120dB at the seats in a worst case scenario, with significant content potentially well below 20 or 16Hz.

3. In spite of 1 and 2, there are some guidelines out there. You know about the AH room rating protocol, so I won't rehash that. There are also the THX certifications, with the Ultra in particular being geared towards 3000 cubic foot theaters. Will a THX Ultra subwoofer deliver 120+dB at 20Hz at your seats? Heck no. Instead, THX has analyzed a wide range of movies to come up with a halfway realistic specification for what it would take to do a competent job with reference level reproduction. Looking at something like the Monolith 12 measurements would give you a fair idea of what they expect is required, and you can compare those measurements with various other subs.

Thank you, Steve. Very clear and without overburdened details. I can, and have to, accept point 1.

Point 2: indeed! I think as I learned more about the definition, I went from brazenly saying "I want reference level" to saying "at or near." A small distinction, to be certain. When I saw Force Awakens at the local cinema, they were clearly feeling their oats with the sound system. I think it was the loudest experience I've had, bordering on complete discomfort. And so again, for the short term, experiencing the sound and feeling of an orchestra as if I were there is an important thing in my experience. Much like Beethoven "hearing" the vibrations of the piano as he worked by resting his head on the piano (one story, another more detailed is that he held a pencil in his teeth and put the other end against the soundboard of his piano). Likewise, I had the bell and bow of my main sax soldered so the full instrument would be more resonant as a whole. Alas, I digress.

Point 3: OK, I can see a little bit better why the Mono 15" is edging out the Outlaw X13, for example. Gonna look for good examples of sealed vs. ported to help me out there as well. I kinda wish I could find a little more info on Rythmik for comparisons sake. Data Bass has F18 and FV18 to compare, but that's not realistic for me, (though likely educational as I can see how their ported vs sealed may compare).

Very Cool. Again my thanks, Steve!

 

[shadyJ]

If not there, than test charts? I recall a max output graph on Data Bass, but I don't see those anywhere else that I recall.
And then there are the CEA test charts. (spl you want high; thd, low... what is the harmonic limit representing?) (Just using the X-13 review from here... you, Shady?... cos' I had it open in another tab.)
Is this where I need to be looking?

Steve had good answers to your other questions. Regarding max output, there is the maximum long term output graphs from data-bass.com. They look like this:

and are basically made from the highest level sweep in the compression graph, so it comes from this graph:

In my reviews, that measurement is depicted in this graph:

I use the same measurement technique that Josh does, do those graphs contain the same information, they just look different. What matters is that they show how loud the sub can get with a continuous tone. That is different than how loud they get in the CEA-2010 measurements, which tell us how loud the sub gets in a burst, a brief moment. CEA-2010 testing also puts a cap on the distortion that is allowed, where the long term output sweeps are not limited by distortion quantities.

The 'Harmonic Limit' cell in my CEA-2010 tables are what kind of distortion that is occurring which is limiting the test from achieving higher SPL readings. To get a better sense of what that means and why that matters, read the section from this page that is subtitled 'A More Sensible Metric of Distortion' which discusses how and why the CEA committee established those distortion thresholds for the CEA-2010 testing standard (what is written there is not the whole story, btw, but it is a good primer).

 

[shadyJ]

By the way, one thing I want to add is that a lot of people just go by the CEA-2010 measurements to determine the output potential of a subwoofer and seem to ignore the long term output tests. Their argument for that is that "real world is more like transient peaks than sustained tones." This is a mistake. Most content is a combination of both. If you only listen to drum kit recordings, than yes, CEA-2010 is primarily what you should be looking at, but if you listen to pipe organ recordings, the long term continuous tones matter more. Most people who are trying to understand what a subwoofer's maximum output potential is like should be looking at both. I think what draws a lot of people to the CEA-2010 measurements is that it sums up the subwoofer's performance in one neat little number, and that is easier to deal with. But that is like judging a car from its 0-60 time alone, it does not at all convey the car's overall performance.