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
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?