(2 x ) 20" T60: Hits the spot!

[ALAZDAK]

Background
After turning from bass player to "sound guy for the band" and then "sound guy for parties" when I headed off to college, I slowly fell out of love with my T48s. That's not to say drunk college kids don't love what they have to offer, but, as I "stored" my system in my large dorm room and spent countless hours listening to music for my own pleasure, the super-hot top end of the T48s, coupled with their ~35Hz cutoff (when corner-loaded) grew tiresome.

This summer, with a decent job and time to kill, I constructed an entirely new system, one to which I planned to listen in my dorm room and one with which I could still provide sound for parties:
(4 x) Jack 12 (3012HO)
(2 x) T60 (20", LAB 12)

I plan to build a couple more T60s this winter or next summer.

Review
I couldn't be happier. These subs do everything the T48s could not.
Don't get me wrong - the T48s are phenomenal subs for bass guitar and general live sound, but the T60s are a dream for recorded music. They handle the lows of rap music with ease; I no longer worry about the awkward "dead space" that arose whenever a huge sine-wave bass note would fall beneath the steep 37Hz hi-pass I used to spare the T48s. And who couldn't love the look on people's faces the first time they hear sub-40 (and sub-30) bass boosted nearly enough to keep pace with the falling LF sensitivity of their ears?

Where I've really come to love the T60s, though, is in my mid-fi dorm room setup. I placed each of the subs (standing on-end) in different corners of the 11'x14' (SMALL!!) room to provide a bit of modal smoothing. After applying the PEQ of a Behringer UltraCurve (one of my favorite toys) to zap room resonances and deal with the obscene (over 20dB) sub-40Hz response mountain resulting from intense cabin gain, they sound fantastic. Unlike the T48s, they don't sound 'horny,' even despite a higher lo-pass.

It's really quite an experience to listen to a system which, from 24-30Hz (think: Daft Punk's Solar Sailor), will drive your ears to distortion long before breaking a sweat itself.

I'd be happy to post pictures & in-room response curves if anybody's interested.

Summary
Picky DJ? Nutty Audiophile?
This sub's a crowd-pleaser and listener's dream alike!

[Bas Gooiker]

Great review... now show us the pictures of your potentially eardrum ripping dorm room setup.

[Ryan A]

Thanks for the informative post. It has me seriously considering my next build. 40hz just doesn't quite do it for me sometimes.

Any T60's I build won't be for a dorm room though...that's insanity

[ALAZDAK]

what did you mean by 'horny' did you mean the Titans had a little more 'bonky' or 'boxy' knock on wood sound to them compared to the pure and lacking harmonics Tuba 60 tones?

I do not intend to seriously condemn the T48 on such a thin subjective observation.
I have no sort of measurement on hand to show what I perceived, nor did I used pursue 'best practices' for bass in small rooms as I do now.

That said, regardless of the space in which I used them or the frequency at which I crossed them over (though I never crossed them lower than ~80Hz, 24dB/oct), they became unpleasantly easy to localize at very high volumes.

I cooked up a few possible explanations:

-Cabinet vibrations. The very large mouth of the T48 is not well braced in comparison to the rest of the monstrous horn. The "knock test" is relatively useless, but the mouth of the T48 rings like a drum.
Then again, so does that of the T60, from which I've never heard such a 'boxy' sound.

-New crossover. I now use 48dB/oct slopes (best thing since sliced bread). The 24dB/oct slopes may not have sufficed to suppress to overwhelming rise the T48's frequency response above ~100Hz or so.
However, I now cross my subs higher than I usually crossed my T48s. So much for that idea.

-Room vibrations. I'm talking about sheetrock, floorboards, garage doors, and literally anything near the horns not as well-braced as the horns themselves rippling like flags in the breeze when the Titans were sipping more than a watt or two of power. Not to be confused with room resonances, though those are a likely culprit as well, given I've only recently obtained an equalizer suited to attenuating them out of existence.
I feel these are the most probable causes. No fault of the T48.

As I've never my Titans outside or in the same room which now houses my T60s, I can neither make a direct comparison between the two or conclude the T48s' design was the cause of what I perceived to be a 'horny' sound.

[Radian]

Don't get me wrong - the T48s are phenomenal subs for bass guitar and general live sound, but the T60s are a dream for recorded music.

I suspect if you had built a quad of T30's in the first place, you wouldn't have been switching subs.

That said, regardless of the space in which I used them or the frequency at which I crossed them over (though I never crossed them lower than ~80Hz, 24dB/oct), they became unpleasantly easy to localize at very high volumes.

That's because 80 is too high for all but a full-width stack of four. I'm surprised you had any satisfactory 35-50 Hz response at all. The only reason you find the T60 more pleasing now is because it has a flatter native response to begin with, which happens to work relatively better with your particular choice of low-pass filter frequency.

As I've never my Titans outside or in the same room which now houses my T60s, I can neither make a direct comparison between the two or conclude the T48s' design was the cause of what I perceived to be a 'horny' sound.

[Ryan A]

The only reason you find the T60 more pleasing now is because it has a flatter native response to begin with

It can't be the extra extension, it just can't be (sarcasm). The content down there is more than a person thinks especially with newer music. T48 starts dropping off significantly below 50-60 hz...whereas T60 doesn't drop off significantly till 28 hz or so. That's an entire octave's worth.

[Radian]

PM sent.

[Bill Fitzmaurice]

-New crossover. I now use 48dB/oct slopes (best thing since sliced bread). The 24dB/oct slopes may not have sufficed to suppress to overwhelming rise the T48's frequency response above ~100Hz or so.

That one factor would make a world of difference. If you can directionally locate a sub you're hearing content above 80Hz, if not above 100Hz.

[Ryan A]

I'd be happy to post pictures & in-room response curves if anybody's interested.

It's always nice to see build pictures or even pictures of the finished cab. Everyone seems to have their own finishing touches which make it interesting. Post if you have 'em.

[ALAZDAK]

Dear Radian,

I suspect if you had built a quad of T30's in the first place, you wouldn't have been switching subs.

I suspect you're right.
However, I built the T48s for bass guitar and rock band PA. I did not anticipate I would make the switch to party playback in college.

I'm surprised you had any satisfactory 35-50 Hz response at all. The only reason you find the T60 more pleasing now is because it has a flatter native response to begin with

I've only ever used my T48s indoors, primarily in basements and small rooms. Their 35-50 Hz response in such small spaces is more than "satisfactory." Between corner or wall loading and, often enough, cabin gain, the two 30" KappaLite3015LF T48s w/ full-size rear chambers produced LF response curves that, before eq, looked far more like the equal loudness contour than their 2pi Fr. I often had to (significantly) attenuate my T48s' low bass response.

I'm surprised you insinuate that the T60s' considerably greater LF extension has no actual effect on my satisfaction with their performance. I can only suppose you missed the section of my review which directly addresses my annoyance with the sub-40 and sub-30 sine-wave synth bass notes that the Titans necessarily dropped. Again, due to the type of recorded music I play, and, more importantly, due to the tininess of the 'venues' which employ me and that of my own dorm room, 25Hz-40Hz is an important and impressive reality, not a placebo.


Finally, I'd like to know what compelled you to repost the conclusion of my own review as if it were a possibility that had not occurred to me.
I realize the forum reads "Posts: 2" beneath my username, so you may be interested to learn that, actually, I do not appreciate your condescension.

[ALAZDAK]

I will post pictures and response charts this weekend.

Word of warning: I have not finished sanding/routing/bondoing/duratexing the cabs yet. That's a project for winter break.

[subharmonic]

I have never heard a T48 yet but I have done a side by side with a T39 stack, and the ease of lows the T60 and the downright authority it has with them makes me want one T60 vs a T39 stack. If a T60 or pile of T60s gets you the SPL you want and the SQ you were missing. Go for it. After I am done loading and unloading I have no regrets. Even though most of my music doesn't "need" sub 40Hz it sounds better when it is there, possibly since it is not pushing the horn to its fc?

[osse]

Did you try to use a less steep slope at the LPF frequency and lower the freq of the filter to, say 45-50 hz, with the T48's? That way the filter would smoothen out the natural rise in frequency in the cabs, which might be the reason that you experience them to be 'directional' and the localization problem in the room...

I've got quad T30's so I don't know about the T48's but I use this method on mine and they smooth out considerably.

[doncolga]

Did you try to use a less steep slope at the LPF frequency and lower the freq of the filter to, say 45-50 hz, with the T48's? That way the filter would smoothen out the natural rise in frequency in the cabs, which might be the reason that you experience them to be 'directional' and the localization problem in the room...

I've got quad T30's so I don't know about the T48's but I use this method on mine and they smooth out considerably.

Curious...what slope and cutoff do you use for your T30 quads?

[osse]

I've been using 12 dB/oct @ 60 hz, but I've only tried it outdoors with some real benifits over steep filters @ higher freq's... you can't locate the subs and the bass is just everywhere in a very pleasing way. I've been trying indoors but in very stressful situations and in the actual rooms didn't get as good results as with steep filters in that single case, so I need more experience indoors before I can say what I like the most, it tend to let more lowmid freq's in the subs but also cut out the real smack @ 100 hz which can be a bit over emphazised if not dealt with, which I guess is the case with all BFM cabs(except maybe the T60...)