Questions from an SVS user.

Discussion in 'Archived Threads 2001-2004' started by Ryan Cruz, Oct 2, 2002.

  1. Ryan Cruz

    Ryan Cruz Stunt Coordinator

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    When I watch movies, I like to run my sub a little hot (I'm sure a couple of you do), but when I turn up the sub to enjoy loud low frequencies, sounds such as footsteps get overly heavy.

    Am I setting my crossover too high? It's set right now at 60hz and turned on since I can't change it in my Denon AVC-A10SE.

    My speakers are all set to small btw.
     
  2. Charles J P

    Charles J P Cinematographer

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    Well, there are a couple things going on here with the volume and the crossover. Since you are crossing over at 60Hz using the receiver, I assume that with your speakers set to small you arent losing any information (as opposed to setting your speaker to small on a reciever with a 90Hz crossover and then setting the subs crossover lower so that you would actually be throwing out part of the frequency range). So, that being said, you are most likely not crossed over too high, since my sub (an SVS 16-46CS) is crossed over at 90Hz (yamaha receiver) and I do not have the problems you are talking about. So either you are setting the volume WAY too high when you bump it up a bit, or you have placment issues.

    Where is the sub in relation to the room boundries? In relation to the other speakers? Have you calibrated with an SPL meter? I ask becuase if you are setting it by ear, then what you think might be equal to your other speakers might in fact be hot, so when you bump the volume of the sub up more, you might be REALLY hot (like 10-15 dB or more). One other thing is, if your SVS is new, you may be experiencing break-in. Not of the sub, but of your ears. I was actually a little disapointed when I got my SVS because it didnt SLAM like I expected it to. However, there are a few things I discovered. Many movies dont have as much bass in them as you might expect, but due to listening to them with bloaty, non-flat subs that have electronics to bump the upper bass to make them sound better, you are expecting to be rocked by scenes where there might not be that much bass. Also, SVS subs dont generally boom and distort. This means that if there is a 30 Hz rumble on and SVS you get a 30 Hz rumble at the recorded volume while on a lesser sub, you might get a 30 Hz rumble, but you might actually have distortion or harmonics that are louder and boomier than the original tone. Once you get used to your SVS, you may find that other subs (even many considered to be good subs) will sound boomy and unnatural.

    So, in summary, check your settings with an SPL meter so you know where your baseline is, then see if you want to bump it a few dBs, but if you are "ear-balling" your callibration, you may discover that when you increase the volume you may be running the sub way hot and you are going to get unnatural sounds like footsteps sounding like bombs going off.
     
  3. steve nn

    steve nn Cinematographer

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    Hi Ryan-- I am sure you know that there are DVDs out there that do pump up some of the foot steps. Blade is the first that comes to mind. I just picked up the Scorpion King yesterday and on my way home decided I needed to re-calibrate. After doing so and finding I had bumped up the center over time +3db to compensate or should I say appease my wife, I found it really put things back right again after re calibrating. What I would do is bump up my sub to compensate for the +setting on my center, so I would still here "Turn that thing down Steve". If you have not calibrated? I"ll bet you a dollar you will be amazed at what this will do and find a 4-6 db bump on your sub is more than plenty and might even want to cut it back. SVS being SVS--I can't imagine after calibration you will be disappointed. Your other settings sound right. Also just know that many DVDs nowadays "over"? emphasize the .1 and that imo is just fine with me but you might not like it or want that effect in your listening. It will be there though regardless. You then could cut it back[​IMG]
     
  4. SVS-Ron

    SVS-Ron Screenwriter

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    Ryan,

    You are already getting lots of good advice but I'll add a couple things.

    First, if you you have set your speakers to small (typically the best way to go with a high quality sub) you should NOT enable the crossover on the sub (if I understand that's what you did?). Even if your crossover is not variable on the receiver (most Denon's default to 80Hz which is just about perfect and is the defacto THX standard FWIW), let the receiver do the work here.

    It could be that if you calibrated with this arrangement (ideally with a test disk like Video Essensials or Avia, I do NOT trust Denon test tones, and neither should you. SPL meters and a test DVD is THE way, trust me) you might have been shaving off significant levels of signal and consequently are calibrate much higher than you think.

    Get a test disk (if you aren't using one now), disable the crossover on the sub and re-calibrate.

    Second, it's location, location, location (location! ;^). Experiment with it a bit. It could be your current placement is emphasizing a particular frequency band more than is ideal. Without lots of time to measure output at various frequencies it's difficult to know for sure, but make no mistake, the room acoustics are absolutely THE critical factor in how any given subwoofer will perform. Moving the sub a foot or two, sometimes even inches, can make a radical difference in those room bass wave interactions and what reaches your ears.

    Third. If you are dead certain (and only the aforementioned test disks and SPL meter will tell you) your calibration is right, finally consider just what "a little hot" is. If you are watching movies at relatively low levels (I'll spot that at anything from -25 to -15dBs below Dolby Reference level, as measured by a sound meter) then running 3, 4, even 9dB "hot" (over the level set/measured for your mains) is no big deal, and it should sound very good, natural and not bloated in the least. (The ear is increasingly less sensitive to bass at both low frequencies and low SPLs). If you are watching movies at more "spirited" levels, at or a bit below reference level (remember this is no more than most movie theaters, when properly set up) then running "hot" is generally not a good idea. Not unless you have a very small room, or are sporting twin SVS's anyway. Add to the mix some of the simply insane LFE now coming on DVD's (we're talking above reference level bass well below 20Hz, sometimes below 10Hz at only slightly lower SPLs) then you can see why hot calibration on some movies can simply be excessive.

    Last. Some movies are basically mixed poorly. They overcook sound effects, or record the entire soundtrack with little regard to Dolby specifications. Lord of the Rings anyone?? (I'm not saying LOTR is mixed poorly, but it's the most blatant example of recording at excessive SPLs that we've seen in a while). I'd say the vast majority of movies today are done very well though. Just keep an eye/ear out for the outlyers.

    Just a bit more food for though. Remember, if you change ANYTHING, be it location, a crossover setting, anything, it's time to whip out the Video Essentials (or whatever) and the SPL meter and check all channels. I've probably listened to at least 200 different subwoofers in 50 different rooms over the last few years and I have rarely had problems getting calibration levels to sound natural (yet with impact) on even today's block buster DVDs. Starting with a good sub is key, but the rest is just a matter of accounting for the variables above.

    Ron
     
  5. steve nn

    steve nn Cinematographer

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    Darn well said Ron-- I even went so far as to tape of the back location of my sub this time around for its location does change daily. How my wife can move 160 lbs is beyond me. I know--! I will glue it to the carpet with industrial adhesive and that will be that.
     
  6. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Even after I've done the above I still wasn't happy with the way my tempest sounded. My guess is that the noticeable heavy footsteps you're noticing are at a frequency that's amplified by the room.
    The best thing I've ever done to my bass was to start adding some acoustic treatments which only costed me about $15 a panel. It transformed the upper bass like I was outdoors and the imagaging and ambient noise improved as well. When the panels were in, the once boomy sound track of "The Shire" chapter in LOTR became extremely pleasant/musical and gave me goosebumps. [​IMG]
    What people should realize is that the room plays a significant factor in the way bass sounds. You can plug in your room dimensions in my excel file and calculate your room resonances.
    Click Here and also visit "acoustic panels".
    (Soon I'll be doing some testing with bass traps)
     
  7. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    If it turns out that the problem is certain frequency ranges being reinforced by the room itself, I can't advocate the use of a good EQ enough. Whether you go with something basic like the ART-351 that SVS offers (which I have and get a solid +/-3dB flat response with after taming room peaks) or a good parametric EQ, the difference will amaze you.
     
  8. Doug BW

    Doug BW Stunt Coordinator

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    I fully agree with Jeremy. Unless you've ensured that your frequency response is reasonably flat, the exercise of calibration is somewhat meaningless....it gets your bass levels in the right ballpark, but that's it.

    When you calibrate to pink noise, you're setting your sub to a level where, on average the level is correct. If you have a big peak or two in your frequency response, then the "average" level will be the wrong level for most frequencies. The peak frequency will be way too loud and other frequencies will be too soft. If you play a soundtrack where the footsteps happen to be at the peak frequency, then they'll be way too loud. If you turn your sub level down to make the footsteps sounds right, then the rest of your bass won't be loud enough.

    EQing is one way to flatten your frequency response, along with experimenting with sub (and listening position) placement and room treatments.
     

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