2 x small or 1 x large?

lackboost wrote: »

I recently got the garage clean enough to install my HT gear. Although I have not run Audyssey yet, I have noticed the sub is most impactful at the back of the room on the side that its currently located, and almost non-existent in the listening area (room node?). Unfortunately, room is limited in the garage and the 4.0 cu ft box is hard to locate in any other places (read as there is really no point to sub crawl). Seems like having two subs helps with these types of situations, so should I go from 1 x 18" in a massive box, to 2 x 10's or 12's that I can locate more effectively in smaller enclosures (say 2 x 1.25 cu ft)?

Dumb question but any room in the ceiling for a couple subs? Gets them off the floor and to where you can make a couple really large boxes. Also opens up more options for placement, and my favorite type of sub an Infinite baffle configuration..

Check phase adjustment on your amp if you have one. The null in your seating area could be due to phase issues.

lackboost wrote: »

I really wish I had room for another 18. I am noticing today too, in some casual litening:

BACK OF ROOM - HIGH AND LOW: Lots of clean bass
LISTENING AREA - STANDING UP: Little bass
LISTENING AREA - SITTING: No bass

It's literally like hitting a switch...just no bass in the sitting area at all. I have a 15" Titanic. May try putting that in a sealed box and playing with it in the garage to see if I can get some bass in the listening area at all...

If your listening position is in the middle of the room, it will always do this. That's the worst possible spot. Best way to get rid of this is four subs, one in the middle of each wall is the smoothest, or one in each corner is the loudest but slightly sloppier.

I wouldn't give up and go down to 10's or 12's, the only possible way you'd get any decent response out of them comparatively is a real beefy driver in a large ported enclosure, and at that point you're not really saving anything in terms of footprint over a 4 cubic foot sealed 18 box.

Dennis Gardner wrote: »

Check phase adjustment on your amp if you have one. The null in your seating area could be due to phase issues.

With one sub, the only phase issue he'd have is with blending with the mains. If he can mute the mains and there's still a null, well, it's not phase related.

ZLTFUL wrote: »

Output will be greater from a single 18...

The catch is, 2 10s wouldn't come close to giving you as satisfying output as a single 18.

Eh, depends. If he ports them, he could still probably spank a single sealed 18. Single sealed 18's kinda suck to be honest.

ZLTFUL wrote: »

2 12s are borderline but won't dig as deep unless you do some serious work into a folded horn or the like.

Two ported 12's designed properly will dig deeper than a single sealed 18. But yes, sealed 10's and sealed 12's just shouldn't even be on the radar.

ZLTFUL wrote: »

Ideally, 2 18s, sealed, will give you the deepest extension in a small(ish) footprint but you sacrifice some output. The nice part is though, you can throw gobs of power at a sealed sub without worrying about exceeding its mechanical limits.

You can easily bottom out common 18's in a sealed with common amps, all it takes is a low frequency and some volume. Pair up an ultimax 18 with an iNuke 3000 and you can easily make it go clacketty clack where it's smacking that top plate.

just a few questions:

What is the floor made of?

The Walls?

Distance from sitting area to sub?

From what I have read you may have more of a refection issue than anything else. An 18" sub that is being powered properly should cover any normal size garage easy. Now if you have some barn size room then you may need another, but from my experience 18" sub can cover 200-300 seat room.

http://www.svsound.com/collections/cylinder-subwoofers/products/pc12-plus

These

I use the mindset of live music, The sub is not to be over powering but be a blend with all other drivers being used. If you want to rattle the windows be my guess.

Blend with music in an audiophile manner all you want but home theater is a different beast and I'm pretty use that's what we are talking about here. Your LFE channel is by definition 10 db hot even if you have everything set flat, and the frequencies involved are much lower, and you're trying to reproduce them with an enclosure that rolls off pretty steep and high. A single sealed ht type 18 simply cannot hang, and even if you try, you will have lots of distortion. Sealed 18's need eq too be flat, even at 18-20 hz one will be hurting and distorting badly even at moderate levels, and forget about infrasonic stuff. Has nothing to do with being a bass head and boosting the bass to obnoxious levels like you are trying to claim. Has everything to do with setting things up to sound how they ought to for home theater. If you knew how to do that you wouldn't be claiming that a single sealed HT-18 would easily fit the bill. Just won't happen.

@lackboost

Let me throw an alternative your way.... Buttkickers....

I have a 15" D2 Stereo Integrity driver in a martycube box (4 cubic feet tuned to 21hz) and its get LOUD and sounds great...

But I have a HUGE ROOM thats open and I know what I really need is more subs that are sealed if I really want of the infrasonic stuff (which I do). For now the current sub has required me to add speaker gasket to all my picture frames in the area, as well as the kitchen cabinets and add silicone to the inserts in those cabinets so they dont rattle.

Instead of more subs for now I bought a buttkicker for my setup. Initially I installed it under the couch but my wife hated it so it had to go from there. So now it sits under my chair and I tell you it makes a HUGE DIFFERENCE. The ONLY thing I have to work through is potentially getting a MiniDSP as if it gets super low bass it starts to ping a bit, so I'm thinking I need a crossover somewhere in like the 10hz range or something. Its a known issue due to the fact the amp is flat to 3-5hz according to the manufacture.

But its giving me the feeling of infrasonic without requiring another big box.

I'm still going to try for dual sealed 18" ultimax's in 4 cubic foot boxes, but for now I'm happy.

And if I wanted my amp is capable of driving up to 4 buttkickers so I could add more of them without having to pay for another amp.

1 big and add a matching one later

This is a challenging room, you might end up having to chase down all kinds of rattles.

lackboost wrote: »

Agreed that LFE is hotter. When I play music (MP3/CD/FLAC) the sub level needs to go up...way up to provide adequate output. I have plenty of output with the single 18 in a sealed box that seems HT-worthy to me (low freq). Its just not in the right place. As I am limited on space and cannot to have 4 x 1500 watt amps and large boxes lying around to achieve my end goal, it is imperative to make this single 18 work in the space provided. I have a mic coming and have room treatment elements lying around. Will room treatment help in "moving" the bass to the listening position? Interesting, seems like listening position bass improved with garage door open. Maybe treat garage door to minimize reflections?

No, not at all, especially not with putting up panels to treat reflections. Large bass traps may help smooth the peaks a small amount but it won't fix what you are describing. Everybody talking about the reflections isn't reality because the bass frequency wavelengths from the subs is so long they're just going to rip right through any panels you put up.

Ideas that may help:

1. Change to a ported box. A single sealed 18 will always suck. Sorry but it just will. F3 on a sealed 18 is like 31 hz or something and it just keeps falling below that. F10 is like 18-20 hz. That's just awful. Switch to a ported box and bump up some of that low end. You should be able to get like 6 db more near the tuning frequency, which would be the equivalent of doubling your current setup.

2. Go with multiple subs, which is the best way to fix it. It's the only real way to smooth out all the peaks and nulls, especially in the middle of the room.

3. Move your seats to out from the middle of the room. Everybody has nulls there, especially with subs in one location. It is literally the worst possible place to sit. Typically near the opposite wall is loudest.

4. Draw out a diagram so everybody knows what you're talking about.

ZLTFUL wrote: »

Uh...ok...that's why sealed 18s are the go to for nearfields virtually every high output theater showing up on AVS...

Nobody's rocking a single sealed 18 for their entire system in a decent sized room like the OP's garage, calling it good since the performance is so good, and being justified in that decision. Not going to happen. It's just not. That is literally what we are talking about here.

ZLTFUL wrote: »

I think you are confused here...they will have higher output but even properly tuned, a UM18 will still dig far deeper than a pair of "off the shelf" ported 12 enclosures. Until you get into exotic long tuned port lengths, the depth those 12s can dig won't go nearly as low as a sealed 18. I agree that a properly ported pair of 12s can far exceed the *output* of a single 18 but they won't dig as deep.

Sorry but I'm not. Even among factory offerings, take some quality 12's and you can dig lower than a single sealed 18. Look at the Klipsch THX 12's. Play a pair of those at 20 hz and tell me they won't spank a typical sealed 18 doing the same. A pair of those can supposedly play 122 db at 20 hz.

Now, head over to data-bass.com where they measure several 18's in a sealed box. They got 105 db out of an ultimax. They got 108 db out of an HST. That's because the things started rolling off above 30 hz.

Let's go down a little lower. At 15 hz the THX claims to be at 112 db. Even on the HST, the max burst is about 100 db. Even if the claimed output is way off, that's still 12 db. That's huge.

The only way to get satisfactory deep bass with sealed subs, even 18's, is with multiples. Single sealed 18's just suck. If they didn't, you and I and most everybody else wouldn't be running four or more of the things. A sealed ultimax for example in a typical 4 cubic foot box has an F10 of 18 hz. That's 10 db down at that point. That's huge. Takes extra woofers and a lot of power to make up for that.

ZLTFUL wrote: »

I am not disagreeing simply for the sake of disagreeing but I've known guys like Steve Meade for years and their consensus is, if you want loud without having to use a ton of power, go ported. If you want accurate and to dig deeper with the ability to increase output simply by adding power and damning the eq, go sealed.

You seem to be forgetting that we are debating a single 18 here. One. Uno. A setup whose F10 is right where things get the most fun.

And digging deeper all depends on how low and loud we're talking. For example, if you take two subs, one is sealed, one is ported, and the sealed one is 10 db down at 20 hz while flopping around quite a bit and producing a bunch of distortion, and the ported one is still flat while sounding good due to little cone movement comparatively since we are at its tuning frequency... which one would you say digs deeper? Ported, no?

Now take the same setup and cut the frequency in half to 10 hz. At this point the ported box is unloaded. There is no backpressure from the port, so the driver flops around violently, and the front wave is being canceled out by what comes out of the port, so about all you hear is suspension noise and port huffing. Yet, the sealed is still chugging. Nevermind that it would be lucky to crank out 90 db without destroying itself due to xMech limitations at this point and distortion is off the charts, but hey, at least it's measurable right?. So which would you say digs deeper? The sealed, no?

The second situation is negated by the fact that you only have one sealed 18 which would sound horrendous when you try to do this. It would simply sound better if you ported the thing. You are shooting yourself in the foot by hoping for virtually nonexistent 10 hz performance while sacrificing output from 17-25 hz. Which makes absolutely zero sense.

Meaning, yes, when comparing apples to apples, sealed can produce lower frequencies due to a more shallow rolloff below the ported box's tuning frequency, but you need multiple subs to pull it off, otherwise you would be better off going with a ported sub that performs better at its tuning frequency and a little above, and in the case of 12's, can at least cover the frequencies that you can actually hear in a satisfactory manner, which a typical single sealed 18 simply cannot do, because its rolloff starts way higher than the ported one. Plus, you're still better off with two subs due to room mode issues.

ZLTFUL wrote: »

Me, I go with a mixture of the two...4 sealed 18s and 2 ported 12s. But then they also serve different purposes.

I'm doing the same thing, four sealed ultimax's as well as acoustic elegance 12's for midbass. I'm pretty sure I'm familiar with what sealed 18's can and cannot do. I'm just now happy with the output. If I could only run one of them I would not be happy whatsoever, I'd at least port the thing. Running only one of these in a larger room like a garage isn't exactly optimal for home theater to say the least.