15" vs 18" subwoofer - which to buy?


If price and room space/aesthetics were not a big issue, is there any reason to get a 15" subwoofer over an 18" one? My main issue is not disturbing the neighbors too much. I'm confused about the difference between a 15" and 18" subwoofer. I want to get the best sound quality possible for low-to-medium volume use.

I've heard that an 18" subwoofer can be played at low decibels and provide good bass resolution and fullness of sound, while to achieve the same volume with a 15" subwoofer, the power has to be much higher. So for any given sound volume, the main difference is in distortion- and higher distortion sound may be more obtrusive. Is this true? it seems counterintuitive that an 18" subwoofer could be better for neighbors than a 15" subwoofer.

However, I compared a B&W800 (12") vs B&W850 (15"). I listened from the other side of the store wall (not as thick as my apt), and at minimum levels which I found satisfying for HT, I found the 12" more obvious and 'boomy' sounding while the 18" produced a more subtle (though actually more powerful), lower frequency vibration, like a very low-level rumbling background earthquake. The 15" subwoofer did seem more of a disturbance because of it's 'obvious' sound. However, I worry that an 18" won't even start producing quality sound until a certain volume that was much higher than a 15", and consequently potentially more disruptive for neighbors. Is this true? What is the relationship between subwoofer size, low sound volume, and subjective listening experience?

Unfortunately, it will be difficult to get an opportunity to hear both the DD-15 and DD-18 which I am considering, so I hope someone can help out here.
no_slouch
El: I never said that i doubted your test results, so why would i bother trying to duplicate them? What i'm saying is that this is probably not the most appropriate manner to try and ascertain the type of information that we are looking for. Sean
>
Sean...What are we looking for? I thought it was a variation of sensitivity (dB/volt or dB/watt) as a function of SPL, particularly evidence of a reduction at low SPL. That's what I looked for.
Thanks everyone for your comments.

I put in an order for a black DD-18 subwoofer. Originally I thought I wanted the maple, but I really liked the gloss finish on the black.

In total, I listened to the DD-12, DD-18, BagEnd Infra18, Rel Stadium III, B&W800 and 850. My impression was that an 18" subwoofer could be played well at low volume. I had never heard a home subwoofer before, and was amazed at what it added to movies and HT, hence I decided to get the biggest one I could. Although the Velodyne retail salesperson and various other people on this forum and elsewhere have assured me that the smaller 12" and 15" subwoofers should work about as well in smaller rooms (they said that room size should be my only consideration), I didn't have the chance to test this. In the small to mid-sized showrooms (250-400 sq feet?), and sitting at a close distance to the subwoofers, I found it hard to believe any number of 12" subwoofers could ever match an 18" subwoofer. The 12" ones didn't seem to have authoritative impact, and in fact I didn't really like the 'punchy' bass they put out- I see why someone might call them a toy, no offense intended to anybody. Is it a non-contested fact that multiple 12" subwoofers could match or best a single 18" subwoofer in terms of quality of low bass? It seemed so hard to believe in the store.

Also, a reviewer for a hifi magazine was in the store that afternoon, and I got to listen in for his review of the 1812 subwoofer for about 45 minutes of home theater, and I decided I wanted to get as close to what i heard there as possible

The DD-18 will arrive in about 2-3 weeks at my apartment, I'll try and post a follow-up around then.
Is it a non-contested fact that multiple 12" subwoofers could match or best a single 18" subwoofer in terms of quality of low bass?
In theory you can do it. In practise it is VERY difficult to simulate a single point source (the 18") with many 12".
You'll be happy with yr DD-18; it's a very good product.
Gregm..."VERY difficult", perhaps, but to simulate a point source to the left or the right with a center speaker is downright impossible. I agree that the Velodyne 18 incher is a good product and will no doubt work well.
No slouch,

I too listened to a DD-12 at a local dealer over the weekend, and while it did a credible job in a moderately large home theater room, it didn't provide the tactile shudder of an 18" sub. Like you, I'm going to go with the DD-18. Still thinking about 2 of them? I suppose you won't know until yours arrives.
Gregm...I'll see your two SW, and raise you one center SW. I also have SW drivers for the rears, but haven't got around to putting them in enclosures.

I think that every speaker system should be flat to near 20 Hz, and that usually means you need to add another driver, called a SW.
El -- OK, I'm in for your centre SW. Driven left+right into one.

I would raise the added drivers called a SW -- to two, open baffle. What do you say?
I am interested in getting DD12. DO you guys use the speaker level or the line level input? And if using line input, is there benefit in using the line output back to the amp? ( increase dynamics vs lost in trnasparency)

Thanks
If you want to hear a musical sub, give a listen to the Bag End Infra-Sub 18. I've heard and owned many subs including NHT Sub Two[stereo pair] with four 10", and Vandersteen with three 8", B&K 15", A stereo pair of Onkyo THX from a $3000.00 speaker system[CRAP] and for 2 channel nothing comes close!!! Although its protection circuitry will shut it down if played loud for any length of time but I’m talking 115 db of dense bass
My gosh, I had to buy TWO gas masks for all the BS I smell in this thread. Talk of stereo bass, need for numerous 18" subs, small Velodynes as toys. The word NEWBIE is written all over this thread. For the umteenth time, it really boils down to just a VERY few things;

What size is your room?
How loud do you like to listen ON AVERAGE?
*if I asked most of you, you would have no clue (we're talking spl's here).
Is the sub capable of low distortion output?

That's all you need to know...period.

Will a larger DD-18 be able to play as well as a 15,12,10 etc. at lower levels? Duh: Of course. Will those other subs have the same low frequency extension as the 18"? Of course not.

As a general rule..according to Velodyne;

2 DD-10's will have slightly more output than a single DD-12, but also slightly less extension. (this extension thing can get a bit complex to explain)
2 DD-12's will have slightly more output than a single DD-15, but with less extension.
2 DD-15's will have slightly more output than a single DD-18, but with less extension.

As for the use of dual subs, there's really only one reason to do this, and that's usually because there's not enough output from a single. And actually, it almost always makes more sense to just get the next size up in subs. I had a DD-10 in my 3500 ft³ condo living room and it did just fine for both music AND movies. No, the low end did NOT have the impact that an 18" would, but damned well did just fine for living in a condo.
I recently moved up to a DD-12, and I couldn't wish nor ask for more. It produces MORE than enough ground shake and special effects for my needs...and I'm an experienced listener.

Like I said, it all depends on how loud you listen to your material. Most folks on these forums (and even folks from Velo) will convince you that you need massive amounts of subwoofing power, but once you get over the initial goofing around/testing it out/demos for your buddies, I guarantee you that you will very likely just "SET IT AND FORGET IT". Trust me, if you're making the most out of dual 18" subs in even a LARGE living room, you're probably doing damage to your hearing with your main speakers.

My buddy has had both a DD-15 and a DD-18 in his 4000 ft³ space and although he's kept the DD-18, he acknowledges that the DD-15 was MORE than enough for his room. He just happens to be the type of guy that needs to have the biggest, baddest, toy of ANY kind. Perhaps he's compensating for something else? :)

The smartest thing that any potential buyer can do is borrow any sub he's interested in and take it hope and play with it a little. Properly calibrate it to your mains and listen to all kinds of material, from music to HT. I'd be shocked if anybody in a 4000 ft³ space absolutely feels the need for 2 DD-18's, much less one. If I could tolerate the size, I know for a fact that a DD-15 would be the max I'd ever desire for MY room, but with my DD-12, I don't even feel the need for that. Then again, I don't listen to loud organ music.

Oh yeah, I forgot to mention the some folks use two subs in order to attempt to smooth out some of the peaks and nulls in the listening environment. Takes lots of time, practice, and measuring equipment to accomplish this effectively.
Truthseeker -

Funny comment:

"My gosh, I had to buy TWO gas masks for all the BS I smell in this thread. Talk of stereo bass, need for numerous 18" subs, small Velodynes as toys. The word NEWBIE is written all over this thread"

Kinda feel that is pointed directly at me since I am the one commenting on using a pair of DD-18s. You picked Velodyne why? You picked a DD-12 and then a DD-15, why?
You picked your main speakers, why? You picked you preamp, why? You picked you cables, why? You picked your transport, why? You picked your power conditioning, why?
I will give you the simple answer: Because you prefered it over another. This is no different than why I personally run a pair of DD-18s.

So many folks say bass is non-directional. Right. While this may be true below a certain point, 20hZ or whatever it is, a sub going from 60hZ (or whatever one has it crossed to) to 20hZ or less is directional and I personally can hear poiint out where it is coming from. Now, if I had a 30,000 sq ft auditorium, there is a much great chance of not being able to do so. Unfortunately, such a thing here in CA is about +$20M, albeit not much more than a home!

When properly set up and calibrated a pair will always sound better than a single.

Dan
Porschecab: I have to agree that two subs do sound better than one if you can afford it and can place them. Two subs smooth the room response, that is why big line array speakers also provide the same benifit.
Otherwise your suggestion about one properly calibarted (aka Velodyne or other mic/eq sub) makes the most sense. But for Home Theater I would love to have two DD18's but my 2 channel takes priority and buying another Wilson Watch Dog is out of my budget right now.

Chris
Good day folks; I also am running two Bag End Infrasubs using my Plinius M8 preamps dual rca outs at line level. My system goals were to augment a full range speaker with a seemless blending full range fast, tight response along with left to right drum kit recreation.I also use Plinius SA102s in xlr dual mono with Mirage OM6s with a claimed response of 18 htz +-3db, Im running lots of power across my front two channels and with a Plinius P8 on my center channel another 400 watts through the use of my transparent ultras and splitter.Now while some may claim overkill Ive found all this power is not corrupting anything in my listening,actually quite the opposite as my significant other listened for nearly four hours one evening when we played Fleetwood Macs "The Dance" among others and Mics use of the kickdrum was recreated through my Bagends wonderfully with my Mirages midrange reponse and lower dual eightinchers recreating the drum kit, the Bagends are so seemless that the only time you know there on is if you unplug them, then instantly ambient spatial cues just disapeer and the stage becomes noticably more less real, somehow they impart a realism to the recorded event that allow one to "see" into the recording.Also a great reproducer of pipe recordings as listening to Saint Saens Boston Symphony on Living Stereo SACDs the shudder of the organs albeit very subtle again imparts that reality to recordings that get lost with just about any single full range speaker. I also have a Mirage BPS400 for huge .1 effects and yes all subs working in 5.1 dolby and dialed in low prefering to use my ear although I have measuring devices that assist I prefer my own ears when dialing in system. So most of my need for my Bagends were simply to augment my Mirages full range response and help provide more subtle spatial cues; that surpisingly found when adding my second sub.Its my belief that theyre are many great and badly designed products out theyre and this is one of the best for musicality purposes, hence the BPS400 is likewise in the effects camp, choose wisely and enjoy. Regards Tim W.
Bagend is the only way to go, the bagend infra sub 18 is not a sub you look at and say that's a great looking sub. The velodyne is a looker, but in sound!! does not compare to bagend. When you put one or two in your system you will "here" why it is so special. Dave
Dgw7000

Did you hear the DD-15 or 18? What do mean when you say "does not compare"?

Tim
Yes, I have heard both the dd 15 and 18 at my local hifi house, I feel the Velodyne is great for HT. I like the dd-18 much better than the dd-15, but for 2 channel the bagend with it's time alignment just becomes part of the music. The infra sub 18 blends so well with anying speaker, your speakers just open up and the bass is just there, so tight so controlled. When you turn off the bagend you say to yourself holly shit!!! This is what really good bass is all about, the music becomes very real. I would say the bagend is the most musical sub I have ever heard. The Vel. to me is one notey!!! Not Musical, but I love the way the Vel. looks!!! The sound is what really matters though!!
I also like 2 REL strada's, which at one point I had in my system. In the end the 18 inch bagend is the only way to go, if you can get it past your wife as your lugging in the room!!!
Dgw7000

I would have to say the local hifi house did not have the Velodyne subs setup correctly. They should call tech. support and get them running the right way.

Tim
Greetings Dgw;

Your sure to stir up some heated debate in your assessment of the Bag Ends comparative performance, yet Ill consider your remarks valid based on your previous equipment, all high quality stuff, money not being the issue.

I must also confess not to care to be misleading in my comments about products to other posters looking in however, that being said, I concur that the Infra 18 is a sealed {not tuned} enclosure that is both time and phase coherent that delivers bass information that's very controlled, detailed with excellent timing and pitch, just does its job and gets out of the way of the important mid range while disappearing into the stage when no low bass information is there, totally integrated into my system yet never, ever, letting you know its position --geographically speaking.

This really is a reference product that should be on anyone's short list for those seeking a low bass frequency specialist sub that has seamless integration, effortless speed, extremely low frequency output, ie. thinking about how realistic the huge pipe organ music with sustained continuous low frequency shuddering/energy is utterly and effortlessly reproduced not to mention stand up acoustic bass like that from the Ray Brown trio or Michael Arnopold from Patricia Barbers catalogue etc.. that's done seemingly with nadda missing, not a note!

Just wanted to add in that last little comment about the sense of spaciousness this sub imparts to better recordings, its almost the same sort of dimensionality tube seekers enjoy in their playback, my thoughts as to whats causing this is perhaps this sub picks up reverberation trails or echoes in studios and venues that most other subs seem to miss, thus contributing one more subtle spatial cue that will greatly enhance the visual glimpse into recorded performances-- most surprising in addition to the terrific bass . " other writers have also commented on this effect in professional reviews"

In my unbiased opinion - YES - one of the very best.

Regards /// Tim W...
As a DD-15 owner with a 2ch system, I'm with Flemke that the Vel was probably not set up correctly in the showroom. Few systems ever are, and this is particularly important with a sub. The DD has great setup utilities, but it still takes time & experimentation and a careful choice of connections & cabling to get it right. At this high level of performance, I'd bet that setup variables account for more variations in listening sessions than the choice of sub manufacturer.

As an extreme example, I was at a Magnolia the other day watching a couple listen to a demo of DSOTM through a basic REL sub. The setup was so bad that the sub was bloated horribly and way out-of-time with the main speakers to the point of laughter. But the customer & the salesman both seemed impressed, and the salesman just kept repeating "REL makes the best sub." Of course we are more discerning...

It's interesting how much passion gets into the sub debate regarding which hi-end piece to buy. I suspect that with fewer options to choose from (relative to the dizzying array of manufacturers building main speakers) the mind comfortably polarizes (ergo the tiresome REL vs. Velodyne debate). Much like in our presidential election, where the country polarizes with all its passions around a simple choice between two candidates at the top of our political system-- either of which will in fact probably end up business as usual.

Dave
The dd18 at the hifi house may not be set up right!!! and I bet over 60% of all people that own the dd18 do not have them set up correcty. That's just another thing that makes the infra sub 18 so great, it's easy to get great sound in any room. The servo chip and eq circuit rob the dd18 from fine detail of music, to much money went into the development of this. Servo's on subs in my view hurt instead of helping the sound. The signal is split apart so many times befor it gets to part of the sub that makes sound "the woofer".
The bagend sub extends to 8hz, even though you can't here it, it allows the sub with it's 400 watt class a/b amp enough headroom a full octave up to handle 16 hz pipe organ. Bagend uses ELF "extended low frequency'. It just works better by getting out of it's own way!!!
The DD-15 has 1/2 of 1 percent of distortion.
The setup is very simple and anyone who owns one should press the auto button. It's that simple.
Flemke, the DD auto setup is a good starting point that can be refined considerably using manual utilities. I believe the auto setup also requires 2.0 software.

Dgw7000, the Bag End ELF sub is intriguing & I hope to hear one someday. From what I read in the reviews, the design entails the unusual choice of a resonant frequency above the operating range of the sub. As a negative result, there is significant roll-off at low frequencies, requiring compensation from the amp that may limit headroom and increase distortion. But in return one gains the advantage of negligible phase shift throughout the sub's operating range. Sorry you don't care for servo controlled subs. The DD servo is variable and user-controlled and the servo is essential-- particularly with large-diameter, hi-mass cones-- to achieve the very low distortion measurement referenced by Flemke. As one reduces servo control on the DD, the bass gets warmer, looser, and less delineated--perhaps delivering more charge to the room, but short on the articulation and speed that I prefer in a high-quality 2CH system. As has been observed, most listeners (particularly in the showroom) tend to favorably perceive high distortion in the bass region as warmth and musicality. Very few systems offer the alternative of clean, extended bass, and this quality can be a little underwhelming at first. But once you get used to it you won't go back.

Dave