subwoofer question


hi everyone, i have a chance to buy 2 m&k mx-150thx(mark I) subs for $900 shipped.
first off is this a good deal or am i over paying.
next, because these subs are old (10-15 years), can they compete with the new subs which use better technology.
i only use my system for home theater.
my room is 14x12.
will these subs be great for my room or should i get one really great "USED" sub like a jl fathom, or velodyne dd series, svs, etc.

thanks so much
nineballg
I'd go with one better sub rather than 2 lesser ones. You can always add a second one later.

The other issue is that the amplifier in the sub is also 15 years old, and you never know when it will need the capacitors changed, etc.
Check the NHT subwoofer close-outs.I bought the A1/X1/W1 system for my HT set-up.It is a very good subwoofer system.My friend bought the same set-up with the single woofer sub enclosures for his bass augmentation ,under the Merlin mxe.He complained a little about the transparency,but this shouldn't be an issue in a HT set-up (.1).He changed the crossover out to an LP-1 and is extremely happy.
The benefit of the X-1/2 crossover in a HT set-up is that there are a myriad of controls at your disposal:X-over freq,phase and boundary control.It also allows for use of two subs and additional routing for a summed/single unit.
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Get a newer one, those subwoofer amps don't last forever. I got two (HSU & A/D/S)subs that both amps just stop working after a few years.
Hsu gives you a decent sound for the money.M&K subs are the easiest subs that I've been able to pinpoint their location in a room.
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
thanks for all your input guys.
i see everyone is against the m&k purchase.
i am strictly home theater not 2 channel.
i do have a audio control bijou equalizer(manual up/down sliders) which smoothes out the frequencies, but doesnt do anything for phase or whatever else the microphone eq's do(audessy, ARC, etc.)

do you really only benefit in 2 channel with 2 subwoofers(left and right)?

for home theater will 1 great high end sub do just as well as 2 subs would... or atleast close to it?
I forgot besides HSU and SVS,someone just posted this the other day if it helps.LINK>>[http://www.hometheatershack.com/forums/subwoofer-tests-archived/6015-index-subwoofer-tests-manufacturer-model.html]
In your size room(14X12),one may get buy.Some have a home trial I believe.It depends on how much thunder you want.
They seem to like it.>>>[http://svsound.com/Reviews/2006-12_S&V_Review_SBS-01-PB12.pdf]
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
Also if you buy used,listen to real deep sounds only while checking it out.This may reveal a damaged voice coil from over driving.It will sound like something rattling or jingling inside it.You may have to put your ear close to it.It should take only a few minutes to hear this.
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Not a lot of stereo information below 40Hz but wont two subs in stereo be preferable to two in mono?
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Perrew,

No.
(Provided that the subs are crossed below app. 90hz.)

IME. YMMV.

Marty
Bob, Marty so if i hear you correctly youre saying there is no stereo info or localization info below 80-90Hz. So the superiority with two subs would be cancellations of node and downside if you take money into account would be you could buy a better single sub?
I've extensive experience with that subwoofer. On it's own, they are fast, accurate, musical, and dynamic. They are good subs overall, yes. You can, however, bottom them out/distort them with strong movie material. That is the downside to any of those MX series, accept the MX5000! That's the truth. That said, two of them, will likely ameliorate that potential issue, help cancel out any distortion between them in mono operation, provide more efficiency into your system(regardless of how you configure them), and more output for sure. However, as far as volume of your room goes, really, one should be enough for that small space. Infact, I wouldn't even mess with two of thoose in that room, I think it's a space killer - unless you can get real creative. It's doable, but usually cramping your space.
For the money, at $900 for the pair, that is a a good deal, as things go. You won't get hurt, and can sell em later, and get the money back.
I would be looking for a simplified solution, myself. Even though you can do more with multiple subs, I'd simplify and EQ in that room. I would NOT be looking for subs placed around the room, in that limited space. Balance is important here, as always.
I would probably say, buy the deal, and see if you can get by with one of them. You may find that one sub is all you need. Place it up front next to your center channel/mains, and be done with it! It will integrate well, have proper phase for all seats, and perform well in that room, with a good EQ integrated into the system/processor.
I guess I'm saying that, if I was in your shoes, yes, I'd go try the M&K's, and see what you think. You'll only ,likely get less accurate bass potential from other choices, and they're easily sold if if you change options later.
This way you'll know what the M&K's are capable of in your room, in your system. Then you can try others later if you want.
Yeah, I'd try em. M&K makes a good overall product, that's very durable too.
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
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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
Marty,

I have a Onkyo 905 for HT duty so it has Audyssey.
For HT I have the sub connected from the sub out on the Reciever, but for 2ch I have it from the speaker so the reciever is not involved.

I guess for HT the Audyssey will be used but I still think the Room corrector in the JL sub might be superior to the Onkyo?

I use a 10" sub because I want the speed in the base to match the speakers however Im still contemplating adding a second sub....
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
Marty,

I should add that I cross the sub very low for two channel, below 40Hz, to best blend with the speakers, so going by your 100Hz limit I could go with the mono setup. I would still use the JL room corrector.
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Marty,

I read through some of the HT/Sub posts but dont find any info on bigger driver being faster, maybe I didnt looke close enough, can you point me in the right direction?
I have tried using the reciever with its EQ in the 2ch chain and the sound is clearly worse for me.

Bob,

when you say the room is too small for bass management from the subs and priferable to go with the full range EQ, what size would you think is approriate before that problem dissapears?

Also what do you guys think about mixing same brand subs but with different driver sizes, a 10" with a 12 or 13"?
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
Marty,

thanks for your answer! I must add that the "clearly worse" was for 2 channel listening. I think the more electronics in the chain is not beneficial.
My system is 95% about 2ch and 5% movies. So its 95% musicality and 5% big effects for me. I run the full Audessey for movies though. but for 2ch the reciever is out of the system.

If your highly damped theory would be applied to two subs from the same brand, in my case the JL Audio Fathoms, it would probably come down to size of box as the decider for if the sub is "fast" or not, but my guess would still be the 10" is faster than the 12". I havent heard both in my system but I found the 10" faster than the 13" in the F113. But still if both the F110 and F112 are equally damped your theory might extend to the possibility of integrating different sized drivers successfully.
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
Marty sorry im not following when you say Box size is not key then say 13" Box will be more damped than 11" for a 10" driver, i.e bigger Box more damped. So if i read you correctly you say a f113 can be faster than a f110 due to having a larger volume relative to its driver? I guess the other parameters will be pretty similar between these two subs so pretty well controlled experiment here. The other hypothesis might be that the smaller element is lighter and therefore moves faster. Do you see any drawbacks with a highly damped sub versus a ledset damped?
I also prefer a highly damped, or "tight" subwoofer, which also applies to woofers in main speakers.

IMO, I think the tradeoff is that ported subs/woofers may have a real or perceived lower depth and/or higher loudness than non-ported models (all other things being equal), but to me they sound looser.
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
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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
Bob, Marty,

thanks for your answers!

We may be down to hair splitting now but if we take two similar subs like a JL Audio Fathom F113 and F112, these are very similar, do you guys still think the F113 ar faster?
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

In the price range that you are looking at, I would go with a small driver sub that doesn't necessarily go really low. I think you will end up rolling it off at 30 hz anyway to take the room out of the equation. I would much much rather have a to little bass than to much bass.
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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
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So in theory

A ported sub will give higher spl levels and lower frequency response but may appear sluggish.

A sealed sub may appear quicker but have lower spl levels and not as low frequency response.
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