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THX2 Cert up'n the anti for subs?


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#1 of 7 OFFLINE   John S

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Posted December 03 2003 - 08:22 AM

I just got one of the subs a few of my friends have on their systems with good results.

AR 12" Powered sub..

Well the box looked like it was deilivered by Ace Ventura.

So I decided to make sure it worked, had Indiana Jones in from the new box set, the sub was flap'n in the breeze on the new THX trailer at reference levels with the sub running a little hot. (slightly louder than true calibration)

Of course the rest of the movie was fine, as was some hard core fusion music, and I even put in another disc to listen to the old Dolby trailer and it was fine.

Just wondering if any 12" powered subs meet THX2 Certification these days? If so which models?

Of course running a 15" Velodyne, I never had cause to give the new trailer any real thought before. But if a movie is going to run those types of frequencies hard, it does indeed seem the sub anti has been raised. Ihad nearly given up on 12" Subs anyways, but this may be the last straw for me with them.

Thanks in advance as always,
John S

#2 of 7 OFFLINE   Dustin B

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Posted December 03 2003 - 11:51 AM

Head here:

http://www.thx.com/m...roductFind.html

Search for subs. Then you'll get a list of those currently certified. For the majority two are required. There are very few if any 12" driver that could handle full reference with the new THX intros. There aren't even many 15 or 18 inch subs that can do it (well if the room was small enough).

You either have to go below reference or get multiple subs, or subs with multiple drivers if you want to reach reference level with ease.
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#3 of 7 OFFLINE   John S

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Posted December 03 2003 - 10:12 PM

dang that is one short list!!!! I think I am going to stop reccomending 12" Subs all together. Thanks for the link!!!

#4 of 7 OFFLINE   Dustin B

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Posted December 04 2003 - 12:53 AM

Keep in mind those are just the subs that have sought THX certification. It costs a lot of money to get your product THX certified.

Bottom line is just because a product isn't THX certified doesn't mean it isn't a great product, and just because a product is THX certified doesn't mean it's a good one (well if it's Ultra certified then you're pretty safe, but they have a bunch of other levels now that end up pretty much meaningless).

Not one of the subs on that THX certified list could keep up with the SVS B4+ (four 12" drivers).

What should interest you more is what Dolby's reference level asks for. It asks for 105dB at the listening position from each of the 5 full range channels (20-20,000hz). Then the LFE channel (20-121hz) should be capable of 115dB at the seats. However there are very few if any speakers that are truely full range so you're better off running all your speakers small, in which case the sub now needs to take over their bass duties upping it's required output to ~121dB to hit full reference. Very very few single subs can do this (infact I believe all the single subs that can have multiple drivers). And most of the subs on that THX list can't hit 121dB at 20hz in room.
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#5 of 7 OFFLINE   Chris Tabor

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Posted December 04 2003 - 02:52 AM

There are two catagories for subs, you have to check subwoofers and powered subwoofers.

#6 of 7 OFFLINE   John S

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Posted December 04 2003 - 03:12 AM

Thanks Chris, I will have another look at it....

My 15" Velodyne seems to hit the mark using a tone generator and an spl meter.

But I am still curious about it all, I would think there are quite a few dual 12" that could hit the mark.

But I just don't single 12" Subwoofers are going to cut it much longer at all. Inheriently (sp?) Movie audio engineers will be making more use of those frequencies, just to get more impact as HT becomes more and more mainstreem.

Yes, the certification is not the big deal to me, but any subs ability to actually pull that sort of demand upon itself off is.

Your PB4+ is sort of a "I called your anti and then up'd it some more" type product, I have no doubt. 4 - 12" drivers, man, 48" of thump!!!!

#7 of 7 OFFLINE   Jon_Krug

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Posted December 04 2003 - 05:12 AM

i would guess that the pb2+ would pass. anyone else have any thoughts on that?