Advice requested for selecting a subwoofer

Boomzilla -- Sat, 01/09/2010 - 19:14

 I'd like to augment my current stereo speakers, which go down to about 40 Hz, with a subwoofer.  In the future, I'd like to add center & rear channel speakers for a full "home theater" rig.  To the best of my knowledge, the subwoofer will need to meet the following requirements:
1.  Flat, smooth, frequency response to well below 20 Hz.   (I listen to both classical organ & D.J. Magic Mike)
2.  Flat, smooth frequency response up to 150 Hz  (I plan to add those meager rear surrounds)
3.  Fast, accurate response for music - I don't want "one note boom boxes" that thud only for movie effects.  The subwoofer must transition seamlessly with my fast main speakers and be unobtrusive in its crossover (which will be done by an AVR, hopefully with individual turnover points for the main, center, and surround speakers)
4.  I would prefer to buy an undervalued, lesser-known, used subwoofer at a ferocious discount, but I'm willing to buy new if I must.
I've previously owned two subwoofers.  One was the shining example of what I want, the other the stinking example of what I don't.  The sub that impressed me was a M&K MX350THX.  Its two 12" drivers were low-distortion, high output-capacity, and played down into the true subsonic range.  I successfully mated it with a variety of speakers (for music & movies) and never noticed the sub as being distinct from the main speakers.  Unfortunately, they aren't made anymore & are exceedingly rare on the used market.
The sub that stunk to high heaven was a JBL 12" that never mated successfully with any speaker that I tried it with, announced its presence at its preferred note (and only at that note), and wouldn't smooth out even with massaging by the receiver's room correction.
The majority of subs that I've researched online don't go very low into the bass frequencies.  They're basically self-powered woofers - NOT true subwoofers.  Some that DO seem to go low, I've read bad things about if you try to run them up above 40 Hz (the Carver & Sunfire models come to mind).  
Subs that look good on paper, but that I haven't auditioned include the Definitive Tech models.  How are they with music?  As the title of this post says, I'm looking for advice.  My priority is music, with the home theater stuff a distant second.  What subs do you recommend?  Thanks!  Boomzilla

firedog -- Sun, 01/10/2010 - 06:10

Have you checked out the JL Audio models? They are very well regarded and they have at least a couple of models that might meet your needs. They've gotten rave reviews in some home theater and audio publications.

One caveat: I haven't heard them at the higher frequencies of 100-150hz you mention, as most 2 channel setups wouldn't use them this way. The truth is, I'm not sure why you want your subwoofer to do this either. Your other speakers would seem to be better suited for these frequencies.

What don't I understand? I'm always willing to learn something.

BTW, it's generally pretty easy to find most of the well known quality subwoofers on Audiogon (especially if you have a bit of patience) at prices for used equipment. But from what you're describing as your needs, I think you will have a hard time finding something at a "ferocious" discount, as you are basically looking for a high performance (read "high end") sub.

Boomzilla -- Sun, 01/10/2010 - 10:59

 Hi Firedog -
Thanks for the reply.  The reason I think that I need response from the sub to go so high is this:  The crossover slope isn't infinite.  Even at 12 dB / octave, the sub is still audible one and a half octaves above the crossover point.  Say I cross over at 80 Hz - at 160 Hz, the sub is still singing along with the main speakers at 12 decibels below the level of the main speakers.  This is enough to muddy the sound for sure.  Therefore, if the sub can play cleanly up to an octave (preferably an octave and a half) above the crossover point, then it is less likely to foul up the sound of the main speakers.
Of course, most AV receivers don't publish the slopes of their crossovers...  The better ones, I understand, use a very steep slope when cutting off the sub (18 to 24 dB per octave) and roll off the main speakers more slowly to prevent having a hole at the crossover point.  That's why (since the high and low pass slopes aren't symmetrical) the phase angle on the sub signal must be adjusted for the best match with the mains.
In my system, I hope to cross over to the sub from the main speakers at a relatively low frequency (50-60 Hz).  The much smaller center channel and surround speakers, however, will probably need to be crossed over significantly higher (probably 100-120 Hz).  that being the case, the sub should be as agile as possible as high into the frequency range as possible.  If I spend more money, I can get some center & surrounds that will allow a lower crossover point (80 Hz?).  I'd prefer to go that route since it taxes the subwoofer's "woofer-capabilities" less.
If I could find an AVR with exceptionally steep subwoofer cutoff slope, I'd be less likely to need the sub to extend into the normal woofer's range.  Since I can't be sure of that (and since I have previous experience with a sub that wouldn't integrate well), I'd like for the subwoofer that I buy to also function as a fast and articulate woofer.
I agree that Audiogon is probably my best hunting ground, and also agree that the "ferocious discount" that I desire is most likely only at garage sales & CraigsList.  Unfortunately, the likelihood of finding a high quality sub in those venues is slim (not impossible, but indeed, slim).  I'll do some research on the JL Audio line (I'd thought that they were primarily an auto-sound company, but I'm obviously mistaken).  Again - Thanks for the feedback!

 A good sense of humor makes it ALL sound better!

firedog -- Sun, 01/10/2010 - 13:29


Thanks for the explanation.

JL Audio was an auto-sound company, but branched out into high end subwoofers a few years ago with significant success..

sheepherder -- Sun, 01/10/2010 - 11:05

 For what you are looking for try REL.  They are great with music and as a LEF.   I currently have 4 Studios along with Maggies in my HT room. I have used REL subs for over ten years now. Where do you want you crossover point to the sub 80hz is a good starting point.
And I have heard M&K is back BTW.

Shenandoah Valley, VA

Boomzilla -- Sun, 01/10/2010 - 11:09

 Thank you, Sheepherder - I'll look at REL also.  If M&K are back, that would also be great!

 A good sense of humor makes it ALL sound better!

TomH -- Sun, 01/10/2010 - 13:29

Hello, you may also look at the Paradigm's   sub-15 and 25. I have the older Servo-15 series2 and its crossover arrangement works quite well. you can use the LFE output of your AVR and fine tune the subs rolloff frequency to your main speakers for a good match for music where you don't want the sub to go up into the mid bass . The x-30 crossover is variable from 35hz to 150hz. The Servo 15 has mated well with my Hales system two signature main speakers , Its not at all boomy, it is clear  and well defined , fast detailed etc. Its low frequency cutoff is 14hz  and can produce the lowest organ notes with great power AND definition. Movie effects?? Make sure things are well secured ! Plants , lamps etc can find there way to the floor.

Boomzilla -- Sun, 01/10/2010 - 15:01

 Hi TomH -
Thanks for the feedback.  I know that Paradigm has an excellent reputation for high quality and reasonable price.  Their pricing means that they should be relatively common on the used market.  I'd really prefer, however, NOT to have an outboard crossover.  For reasons of "family-friendliness," I'm trying to have a single box (the AV-receiver) that can do it all.  The better AVRs allow a selection of discreet sub crossover points.  Although this isn't as elegant as your continuously-variable X-30 crossover, it should suffice.
How agile is the sub-15 in the upper bass?  Thanks again - Boomzilla

 A good sense of humor makes it ALL sound better!

TomH -- Sun, 01/10/2010 - 18:10

  It will suffice, you don't have to use the x-30 ( x-35 now .. I think) but it comes with the sub and it is very small about 7 by 6 inches. The Servo 15 seems very flat in its operating range up to 150 hz. It took me months to really get it dialed in just right , but I always found the lower the x-over the better . For my system it worked out to about 55 hz, when you get  the x-over to high it colors and muddies the sound and makes the sub easy to locate. It should just blend in the same way your main speakers woofers blend in with the tweeters. It just takes time to get it right.

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