PB2+: Boomy-Bass with Underworld?

Discussion in 'Speakers' started by Khai, Feb 8, 2004.

  1. Khai

    Khai Extra

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    Hi everyone,

    I've been constantly trying to tweak my sub ever since I've had it. My room is small and is only measured at 12 x 15 x 8 feet and I have the PB2+ located in the front left-hand corner of the room - which is the only real place it can reside due to the my limited room space.

    After spending literally hours of moving the sub around within the small space that I have to work with, I have concluded that if the sub is right against the corner wall (with a West/East configuration and the ports facing East), then it sounds quite boommy and undefined but you will gain around 1-2dB extra.

    Moving the PB2+ away by about a foot from the corner-wall seems to yield the tightest bass I can get from that corner placement.

    I have the PB2+ tuned to default with 3 ports open and have it calibrated to 85dB with the cross-over set to 80hz (speakers set to small).

    With movies such as Titan AE DTS, Minority Report DTS, U-571 DTS, LOTR: FOTR/TTT (2-disc edition), Fight Club, Toy Story II, Finding Nemo, Monsters Inc, Blade II DTS, The Haunting DTS, Jurrasic Park III, and many other reference dvd's the PB2+ performs superbly, offering extremely tight clean bass which is not boomy at all.

    But then I recently put on Underworld (after hearing how much clear, low LFE the soundtrack had) and was really really disapointed by the bass I was hearing from the sub.

    First off, it sounded very boomy and undefined and overblown that I thought that there was something wrong with my PB2+ [​IMG]

    But I quickly took Underworld out of my dvd-player and put in U-571 to double check that there wasn't anything wrong and gone was the boomy, undefined and overblown bass.

    I know that the the boomy, undefined and overblown bass I'm hearing from Underworld is not down to my sub's performance and the problem is probably not down to the dvd's soundtrack either going by the very possitive reviews on the net regarding the soundtracks LFE.

    So why am I getting boomy, undefined and overblown bass with Underworld ?
     
  2. Edward J M

    Edward J M Cinematographer

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    When you say crossover set to 80 Hz, you mean the crossover in the AVR, right? The crossover switch on the PB2+ should be set to "Disable" if your speakers are set to small.

    If you are getting "extremely tight clean bass which is not boomy at all" on all of your reference DVDs, then naturally the finger points at Underworld and not the PB2+.

    I've watched Underworld a few times now. It has fairly strong and deep bass in few scenes, but it's certainly not at the top of my list as a reference DVD in terms of bass definition and character.

    Regards,

    Ed
     
  3. Mike Sloan

    Mike Sloan Second Unit

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    UnderWorld was the loudest/hottest cut DVD's I have ever played...louder than the 1st theatrical cut of LOTR. There was lots of 30-50hz stuff throughout...and it was loud...the grenade down the elevator shaft was interesting. I did not consider it "bloated". If music and other DVD's sound ok...I wouldn't sweat it. The Patriot has some pretty "tight" and controlled bass...take a listen to that...also...this "bloated" quality (if you suspect a problem) should be evident with music containing low bass.
     
  4. Ron Stimpson

    Ron Stimpson Stunt Coordinator

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    Kai,

    What Ed said about the crossover. It should be disabled on the sub.

    Also, what did you use to calibrate your sub? You mentioned 85dB. Is that with receiver test tones, Avia or some other disk? If your other speakers are also set to 85dB the source of the test tone is still key.

    It's always good to double check with your calibration setup when something sounds overwraught. I'd try Digital Video Essentials (use 75dB for that) or Avia (85dB for this) and your SPL meter to make something didn't change you were not aware of, or forgot about.

    Barring changes there, rest assured this wouldn't be the first movie DVD that had (intentionally or not) "over cooked" bass.

    Ron
     
  5. Michael__M

    Michael__M Stunt Coordinator

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    The Underworld DVD is definitly mastered a bit hot. There are some scenes that are good and then it just goes crazy. I wouldn't calibrate your system according to this disc. As you stated, all the rest of the DVD's sounded great. I would leave the sub where 99% of them sounded great and just deal with the poor 1%.
     
  6. MikeLi

    MikeLi Supporting Actor

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    If everything else sounds ok and youve checked your calibration to make sure your ears are not playing games with you then I would think it would be a hot DVD. There was one mentioned not too long ago... can't remember for sure but could have been Matrix2?????? Anyway just go over and turn down the gain a bit for your hot movie and things will be just fine. Unfortunantly we don't have alot of control over what the mixers do with their movies. BTW I have had to take back and return DVD's that simply were a bad burn so to speak. Got home with the new one and things were fine.
     
  7. Keith Hyde

    Keith Hyde Stunt Coordinator

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    Sounds like a goof on the mastering. Maybe done with lower end home subs in mind. If your other flicks are good, my guess is you just discovered some reality behind the hype.
     
  8. Lewis Besze

    Lewis Besze Producer

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    Underworld is definitelly compressed[read loud],and is a sound mix mass IMO.Yes if others sound good in your system then it's the DVD to blaime. I was certainly not impressed by it at all.
     
  9. steve nn

    steve nn Cinematographer

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    I thought the bass/LFE in UNDERWORLD was definitely lacking. Sure it was hot and thats ok with me but to make it sound close to right I had to cut the LFE trim back along with the gain. It still sounded a little off imo. It could be a number of things that bring this about but time has taught me in the rare situations it does come up> It is not my SVS's fault.
     
  10. Zack_R

    Zack_R Stunt Coordinator

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    I concur,

    IMO Underworld had so much bass presence throughout that bass impacts were less exciting.

    One of my favorites for a low bass surprise is the black rider in the marsh clip from LOTRTT. There is a mild build up of music and then Wham, the dragon flaps its wings.
     
  11. Seth_L

    Seth_L Screenwriter

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    I don't know what you all are talking about. The bass in Underworld is impressive. It sounds like your subs are not up to the task of reproducing it cleanly. The movie is several dB hot (probably 6-8dB). Your amps could be clipping (or the recievers outputs could be clipping). There are a lot of possible answers to your question, but I can assure you there is a pile of very low frequency content in it that never stops the whole movie.
     
  12. Khai

    Khai Extra

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    Ron Stimpson,

    I always calibrate my speakers and sub to 'exactly' 85dB using Avia as I find that this gives the best ballance on most dvd's. Plus I watch most of my movies near reference level anyway but in Underworld's case I had to lower it to -20dB otherwise it would sound too uncomfortable.

    Ron, can you or anyone name me other high-profile dvd movies that contain soundtracks with "over cooked" BUT with undefined/boomy bass?

    Btw, I think that LOTR: FOTR (2-disc version) has over-cooked bass BUT the bass is very tight, clean and defined as oppose to the exact opposite bass from Underworld.
     
  13. Khai

    Khai Extra

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    Zack_R,

    Thats exactly how I felt about Underworld.

    As for black rider in the marsh clip from LOTRTT, each time the dragon flaps its wings on the PB2+, it pressurizes the room with extremely tight and very low bass that is felt much more than heard. The PB2+ definitely played that scene with more impact than my Velodyne HGS-18.
     
  14. Chris A H

    Chris A H Stunt Coordinator

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    I had to do the same...
     
  15. Khai

    Khai Extra

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    Seth_L,

    Exactly, because I heard so many possitive comments regarding the LFE on Underworld, I was really expecting well defined bass like something along the lines of Daredevil DTS or
    Blade II DTS. That did not happen which prompted me to post this thread.

    As the whether the PB2+ is up to the task of reproducing the LFE to the Underworld soundtrack cleanly, given the fact that the PB2+ has absolutely no problems what-so-ever playing the above reference dvd's at reference level very very cleanly with no compression, watching Underworld at -25dB below reference level should not have been a problem for the PB2+. Also it certainly sounds just as clean on all my reference dvd's as it did on my HGS-18, and anyone who has heard the HGS-18 in action will know that the HGS-18 is one formidable performer and I would pitch the PB2+'s performance right along side it.

    I watched Underworld through my Rotel RSP-1066 surround processor and thought that it did an ok job of decoding the soundtrack. But I'm pretty sure that it will sound quite a bit better when my pick up my Lexicon MC-1 soon in which case the bass could possibly sound alot better than it does.
     
  16. Geoff L

    Geoff L Screenwriter

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    Have you plotted the freq response of the sub at your listening position??

    While the UW disc is recorded hot & rather compressed on top of it IMO, it dose have some nice deep bass... BUT, there also is a number of areas of over cooked bass ~{in the upper bass area 35-55Hz}~.
    Could you have a nasty peek, less likely a null, or possible both in your subs in room response (some where in upper bass region)???

    Seeing as you did not mention how flat your response is in room, (only that it dose sounds tight 99% of the time) utill you played the UW disc.

    Is their specific spot/s in the movie you might give us where your hearing this, or is it basicly every where threw the whole movie???

    Edit:
    On the whole, given your comment of 99% tight bass with everything else, I'd be pretty happy regardless!!

    Geoff
     
  17. Geoff L

    Geoff L Screenwriter

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    Post erased!

    EDIT:
    I have no idea how this got here! I posted to another totally different thread and some how it ended up here...:b

    Back to the SVS small room boom...

    Geoff
     
  18. Edward J M

    Edward J M Cinematographer

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    Khai:

    If you are calibrated to exactly 85 dB on the sub with Avia, using the RS meter on C-weighted Slow, the sub is actually running about 87 dB (or about 2 dB hot).

    The RS meter reads about 2 dB low on the typical subwoofer rumble test tone. FWIW, you are showing considerable restraint even running at 87 dB (85 indicated) - many members run Avia quite a bit hotter, maybe 88-89 indicated.

    Personally, I agree with your approach and also have my PB2+ running almost "flat" with Avia. Depending on the surround channel I select on Avia, my sub level varies from 83 dB to 86 dB (indicated).

    Engaging the low pass filter on the PB2+ at 80 Hz, and also setting the low pass filter to 80 Hz in your pre/pro, will simply cascade these two filters. The resulting combined slope of both filters will be sharper and it will roll-off quicker. This steeper combined filter rate will usually create a mild depression (a few dB) at 80 Hz. It won't be audible most of the time, but as a matter of good practice, it is best to disable the low pass filter on the PB2+ if your are doing your BM at the pre/pro.

    Regards,

    Ed
     
  19. Steve Morgan

    Steve Morgan Second Unit

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    I usually listen to movies at -6-10db's calibrated with internal tones on a Lex MC-8. I had to listen at -18db's with Underworld on a PB2 Ultra and VSA S/3. The bass did pressurize a 7500/3 room but it seems the mix was chaotic. I guess you could say over cooked.[​IMG]

    Steve
     
  20. Khai

    Khai Extra

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    Geoff,

    This is something I have yet to do and will hopefully try to carry out a freq response over the next couple of days.

    I did briefly play the LFE freq sweep on Avia and did notice a peak at around 40hz which must be due to my room because I had this peak on all my previous subs as well.

    In Underworld, I'd say that there were 'some' moments of relatively tight bass but on the whole, it was quite boomy and overblown - i.e the explosions sounded nowhere near as tight as say an explosion from U-571 or the tight 'thud' you get with a punch from Daredevil or Blade II.
     

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