At $900 used in a manageable sized room like yours, for HT only use, I would definitely buy a more current single, large sub.
IMHO, a pair of M&K (or any other brand of) subs might make sense for a dual use system where twin subs can be used to smooth bass response without adding EQ, which some people find objectionable for a music system. For HT only, I'd use a single large unit and also make sure that I had Digital Room Correction capability (e.g. Audyssey) somewhere in the chain to achieve smooth bass response via EQ.
Just MHO.
Good Luck
Marty |
The trade of between 1 large sub and 2 smaller subs (all other things - including overall price tag - being equal) is that 2 smaller subs will allow placement that smooths bass response while the single sub (again properly chosen at the same price point) will allow greater clean output. Effects tracks WILL challenge your subs output capability, music usuallly does not.
Therefore, while there's a benefit to maximizing BOTH output capablity and smooth response, at any given price point (shy of zillions) you must choose one (to at least some extent) or the other. My rule of thumb is smooth (2 subs) for music and loud and clean (1 big sub) for movies.
Hope that clarifies MY thought process. As always, YMMV>
Good Luck
Marty |
Perrew,
No.
(Provided that the subs are crossed below app. 90hz.)
IME. YMMV.
Marty |
Perrew,
I've done a/b comparisons with my old Velodyne subs wired for stereo then re-wired for mono. At 100hz, I wasn't sure that I could tell the difference between mono and stereo. At 80hz, I was sure that I could not tell the difference. At 125hz, I thought that I could and at 150hz, I was sure that I could hear a difference.
FWIW and, as always, YMMV.
Marty |
Perrew,
These comments are for HT only, as per your description of your system.
Does your HTR have DRC (Audyssey or similar)?
If so, the DRC will both optimize the x-over function and provide smooth FR over the entire audible range (which obviously includes all the room induced nastiness in the bass). Therefore, the "smoothing effect" of properly positioned mulitple subwoofers is much less important.
Once you're at this point, forget about smooth FR.
What's (mainly) left is clean output capability. Since I use Rythmik subs, I'll use them as an example. A pair of 12" Rythmik subs provide roughly similar clean output capability as a single 15" Rythmik sub. The 12 inchers are $749 per unit and the 15 inchers are $899 per. If your main focus is clean SPL capability (as, IMHO, it should be in your circumstance), the single 15" unit is a better value. As Bob noted, you could always add a second unit later - for any reason.
This isn't the most sophisticated analysis, but IMHO, it doesn't need to be.
BTW, from my previous post, you should note that, at 150hz, it was easy to localize the source of the signal. If you want to x-over somewhere near this high in frequency (and there are several reasons that you might, given specific equipment in a specific room), then 2 subs wired in stereo is important.
Also, please note my caveat. Under reasonably controlled conditions, I could not hear signal localization once I got a bit under 100hz. Other people may be more sensitive to this. It's easy to extrapolate from our own experience and assume that it's universal, but this may not be so. Hence my ever present YMMV.
Good Luck.
Marty |
Perrew,
I'd advise you to sift through the subwoofer threads on this forum. There's a boatload of info that might (or might not) change your mind about a lot of things (including the relative speed of smaller subwoofer drivers). In particular, Bob Reynolds, Shadorne, Drew Eckhard and KR4 (Kal) have offered good insights.
As to Audyssey style DRC for 2 channel music reproduction, that's a bit controversial. Some love it - some hate it - and some (me, for instance) love it with certain reservations. In your shoes, I'd try it both ways to see which sounds better. I'm pretty certain the bass will sound better with Audyssey, but only you can decide whether the price you pay higher up in frequency is acceptable - or even if there's any price at all. See if it's really audible to you, then decide.
Marty |
Bob is correct. My previous posts were my attempt to explain why there may be a common idea that a large driver mean larges inertia, means "slow" bass and why that idea may not hold water. I covered the momentum side. Bob closed the loop by explaining that the extra mass of a larger driver may be accellerated just as quickly as the lower mass of a smaller driver, provided that the force applied to it (the motor assembly) is also proportionately larger.
Bottom line: IMHO driver size and "speed" are not related. I am 100% sure that others will disagree.
Marty |
Off my memmory of comparing these two at audition the sound quality was virtually indistinguishable to my ear. Both sounded very, very good (set up 2 channel with Maggies at a local hi-fi shop). I'm pretty confident that most listeners would find (provided that both are operated within their respective limits and without HT style effects info to distinguish performance below 20hz.) that they sound very much alike. The bigger sub will (presumably) play louder without distortion.
Marty |
It's hard to speculate as to what will work in any given space, although Bob's point is a good one:
Smaller rooms are generally tougher all around.
You tried the full range EQ and determined that it was "clearly worse", so we now know that this approach doesn't work for you. You could try my approach ("bass-only" DRC), but I'm not sure about the best way to implement it for you. I don't think that you can use the internal Audyssey circuit in this fashion - you'd need to go with external hardware, like an SMS-1 between the sub out on your HTR and the subwoofer's input. This approach seems kind of duplicative, but it might work.
OTOH, you could simply go with dual subs and experiment with placement until you find the best locations and leave it at that.
As to driver size vs speed. There's some disagreement, but a lot of the knowledgeable writers point out that large drivers in subs are usually operating WELL below the frequency at which they'd exhibit any problems. IOW a small driver producing 60hz, isn't "faster" producing 60hz than a large driver producing 60hz.
I've speculated that some people might be using "fast" to describe a highly damped sub, since damping is related to the system's momentum/inertia (which, it appears to me, is the issue behind the objection to large "slow" drivers in subwoofers). I'm speculating here about people's issues, so please be aware - this is nothing more than speculation.
OTOH, highly damped systems actually do produce "tighter" bass (no speculation here). Just note that this characteristic is more a function of cabinet size and type relative to its given driver, rather than the size of the driver used. A well designed, giant driver can be highly damped in the right box.
Bottom line: IMHO, if you want a "fast" sub, buy a highly damped sub and driver size isn't particularly relevant. Again IMHO. A highly damped 15" sub will sound "faster" than an underdamped 8" sub. Once more, IMHO. Please understand that many folks here will disagree with these statements.
As to mixing driver sizes, I have no personal experience, nor has anyone shared such with me, so I can't really offer advice.
Good Luck.
Marty |
Perrew,
Just to be clear, box size isn't the key here nor is driver size. The type of box and its size relative to certain mechanical characteristics of the driver determine how highly damped the subwoofer system will be. For instance, a 10" woofer cone mounted in a 13" sealed box is quite probably (but not with absolutely certainty) more highly damped than the exact same driver in an 11" ported box. Choosing a smaller box or smaller cone isn't a reliable solution. OTOH, choosing a sealed box is probably (again, not definitely) a good idea if you want a highly damped subwoofer.
I believe that all the JL subs are sealed designs and those I've heard certainly sounded like highly damped designs to me at audition. Therefore all of them, including the 13" model sounded "fast" by my definition.
You might hear it differently.
Marty |
Sorry, Perrew.
To clarify:
The conceptual design goal of a highly damped subwoofer system is that, once the musical signal is stopped, the system will restrict the tendency of the driver to keep moving. The idea is that momentum is defeated and bass will be tighter (maybe "faster" to some) as the woofer quickly settles.
Hence my suspicion that some people equate big drivers (with lots of momentum) with slow bass. Some subwoofer tests include a measure ("group delay") of a sub's ability to accellerate, reproduce an input signal, and "settle" after the signal stops, but there is disagreement on the usefulness (and threshold audibility) of this spec. Highly damped systems typically show very low group delay relative to less highly damped systems.
Both the driver's inherent "springiness" and the box's ability to inhibit driver travel (this alone is a complex function of the box's size, shape, loading scheme, stiffness, etc.) contribute to the overall system damping. Therefore, there is no universal correlation between driver size, box size, and system damping. I don't want to overstate my technical expertise on the subject, so I'd suggest that you search a bit for technical info on "loudspeaker damping".
A little more bad news. IMHO, a subwoofer can be "overdamped" (too fast in my parlance) depending on the main speaker to which it's being mated. Again IMHO. Again, YMMV.
Good Luck
Marty |
Bob,
I prefer to treat the use of the word "faster" as merely a semantic issue, albeit a widespread one. An underdamped woofer settles less quickly ("slower")and produces a bass character that people (I think) call "slow". I suspect that people intuitively use the word because they correctly relate the quality in question - whatever you choose to call it - with inertia/momentum problems. The false, though understandable, leap is to the causal connection between increased mass and increased momentum/inertia. So, I accept the idea of "fast" bass, I just don't equate it to small drivers.
I might personally choose a different word in describing the phenomenon, but it seems that "fast" bass is usually (although I'm sure not always) understood to mean tight bass. So why fight it?
Marty |
Lambeau,
Not just in theory, but - all other things being equal - in fact. There is one caveat: That group delay is a good measure of "sluggish" (I concede that this is a reasonably big "if").
For an interesting test of this question, find the subwoofer test results for the big triple ported SVS subs on Avtalk.com. This model is sold with removable plugs to fill the ports and allow user "tuning" of the subwoofer. The identical sub is tested with all ports open, then with one port plugged, then with 2 ports plugged, and finally with all 3 ports plugged (effectively sealed). Look at the "distortion @ SPL" results to check the higher SPL part of your question and the "group delay" results for the "sluggish" part.
Marty |
