My sub sounds better after EQ'ing it using the BFD, but...

Discussion in 'Archived Threads 2001-2004' started by DanSt, May 11, 2002.

  1. DanSt

    DanSt Stunt Coordinator

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    New House Curve and graph below
     
  2. Lewis Besze

    Lewis Besze Producer

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    "Chest pounding bass" to me is a "sign" of elevated 40hz bass and more ofthen then not, nothing much below that.
    Commercial cinema is a good example of that.
    Very few cinema has any bass below 30hz[especialy THX ones],so your experience is in line with that.
    Your set up is superrior to any cinema out there as far as bass response goes,trust me on that.
    Good job on the EQ[​IMG]
     
  3. Mike Kao

    Mike Kao Second Unit

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    If you want chest pounding bass than I suggest you go for a dual sub setup [​IMG]
     
  4. rodneyH

    rodneyH Supporting Actor

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    Lewis is right, the chest pounding bass is usually something occurs with peaks around 40-50Hz, all cheap Subs can do that, it is nothing to brag about. You have it set up how it is supposed to sound.
     
  5. Chris PC

    Chris PC Producer

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    It won't shatter the laws of hi-fi to boost the 40hz with your BFD and give it a listen, if you like it better, then so be it. Start with a moderate boost and go up from there. heck, try others frequencies too if you like but remember how to get back to flat [​IMG]
     
  6. DanSt

    DanSt Stunt Coordinator

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    I may try that just for the fun of it. I have 10 different presets. I will just use a different one so I don't mess with these settings.

    So my house curve is ok? Did I make it too steep of a drop off or am I close enough. Just want to make sure before I call it quits and put everything away.
     
  7. brucek

    brucek Second Unit

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    Dan,
    Your graph could be used as a texbook example of how the response should end up. That said, there is no right and wrong with a house curve - each one is different because of the "house". Your curve seems fine though.
    Have you now adjusted the wholesale level of your sub integrated to the mains etc to a level you're pleased with. If you created the curve by attenuating from 30Hz and above, then your overall level may be low with respect to your mains now. Recheck this....
    I totally agree with the others who say that the chest pounding stuff is for cheap subs with one tuned note at 40Hz - yuk........... listen to your system for a while and get used to it properly set up - you've done a good job. [​IMG]
    bruce
     
  8. Warren_Sc

    Warren_Sc Second Unit

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    Sweet looking curve! I might have to get a BFD,too!

    I noticed that the sub is basically tuned to 75db. When I listen at about 80db my sub has peaks around 100db. Before you change that EQ you might want to re-calibrate your system. For all you know the sub is 10db too quiet now.

    Do you have an example of what you consider "chest-pounding"? I just hear the Monsters Inc. preview on the Toy Story 2 disc and I was startled... this is good. It definitely thudded my chest.

    I always thought driving, club-music bass hit around 80hz, and maybe even some at 100hz. Depending on what frequency your sub was calibrated at, you could be as much as -10db in that 80-100hz range.
     
  9. John F. Palacio

    John F. Palacio Supporting Actor

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    DanSt.
    Have you tried just boosting the level of you sub and leaving the curve alone?
    Many people would kill to get a curve as good as that, seriously! NICE JOB YOU DID! [​IMG]
    You might try plotting the response beyond 100 Hz(with your mains on), just to see if something weird is happening adjacent to the crossover frequency.
    Would like to know what the curve looks like once you are happy with the sound.
     
  10. DanSt

    DanSt Stunt Coordinator

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    Hey everyone!
    Lots of responses from everyone...thanks!
    Thanks for the compliment on the curve. I received the BFD on thursday and finally got that curve on saturday. For a while I was getting real frustrated because I would adjust one thing and stuff on either side would go with it. I finally started to figure out just how much bandwidth I needed to program into the BFD. By the time I was done I needed my own personal EQ'ing to drop the peak in my frustration.
    I recalibrated the sub level after I finished EQ'ing. It's currently running a little hot (about 85db with RS SPL correction factored in. All other speakers at 80db). Don't get me wrong. It sounds light years ahead of what it did. Before I was barely feeling anything. Now my whole @ss gets a nice massage while watching the Phantom Menace. And I understand that it will take me a little time to actually get used to not having a 15db peak around 50hz. I keep thinking there should be bass in certain places in the movie, but I think that is just because those places were around my elevated 40-60 hz mark.
    I did try elevating the 40hz area just for fun and all it did was add a whole bunch of boom to the house. Still no "in-the-chest" bass. Is my sub just too far away? Am I just not able to feel the air pressure from that far away? Or am I just underpowered and do I need a pair of CS+ or an Ultra to move some serious SPL.
    Again, I sincerly thank everyone for all the help they have provided. Without this forum I wouldn't have a good sounding home theater at all. I might even be using the accursed BOSE speakers...just kidding [​IMG]
    I love this forum!!!!
     
  11. Ned

    Ned Supporting Actor

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    I think someone said one that the average "chest" resonates at around 80-100hz. I get great floor rumbling bass from my SVS but I wouldn't say it ever pounded my chest. The new THX intro did make one of my pant legs flutter though.
     
  12. Lewis Besze

    Lewis Besze Producer

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    The real beauty to have a good sub is to be accousticaly "invisible" till it really need it to be felt and heard.I think that's what experiencing right now.

    So when you say is that you think that "there should be some bass" is more like you were used to of less "accurate" bass,but in time you'll appreciate what your system can do for you.

    Enjoy!
     
  13. Dave Herkert

    Dave Herkert Agent

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    It looks like you've done a great job with your BFD! I just got one in the last month, and find it to be an incredible unit for the price. I was able to get excellent results with my JBL pro bass cabinets with my BFD - I was amazed that I was so successful.

    Truly good subbage will sometimes make you think that the subs aren't working at times. Seamless integration with your mains, plus a good, flat response from your subs will do this to your head. That's a good thing!! The subs that you hear all of the time - that boom away constantly - are not the subs you are looking for. You want good, extended bass when the material calls for it - but many lesser quality subs linger/boom when they shouldn't. When that boom is missing, some users perceive this as a problem, when in fact you are on the right track.

    If you need more bass, first make sure that the sub is properly calibrated (using Avia or other such disc). Adding a sub is certainly worthwhile - you can add another sub like your current SVS and gain up to 6db of additional output. That doesn't sound like much - but at max output, it will make a significant difference. I've heard the SVS folks say that one SVS will put your lower jaw on the floor, but two SVS will keep it there. That's the difference in the extra 6db.

    BTW - Thanks to all of the BFD mavens here on the board who left all of the great advice. The search feature told me everything I needed to know from the archives, but I wanted to thank all of them while I had a chance. This is quite a resource here!!
     
  14. Steve_Ma

    Steve_Ma Second Unit

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    My room is small, so it was always clear, that more woofage was never my problem. I simply had to learn that more bass does not necessarilly equal good bass and what a properly calibrated system sounds like. Whether I run the sub hot, cold, or neutral (preferred). I have never had this..."Chest Thumping" bass people speak of. I mean I can certainly feel my couch and floors resonating during "bassy" scenes and it gets peoples attention. But I have never fealt this "earth shattering" bass where I could feel the air moving, see clothes flapping, and I was worried about structural damage to my house, and etc.

    After being in some theaters and homes where the bass was implimented poorly...I'm pretty confident that it's not my goal either...Nice curve, BTW.

    --Steve
     
  15. Richard Greene

    Richard Greene Stunt Coordinator

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    For those who want chest thumping bass:

    In 1971 I "worked" with several other freshman

    engineers at the Rochester Institute of Technology,

    using a borrowed signal generator, a pair of DIY speakers with 15" woofers and a case of beer ... to determine the resonance frequency of the human chest cavity.

    It is between 100 and 150Hz. depending on the size

    of the rib cage, lungs, diaphragm, etc. Placing the speakers closer to your chest cavity makes the effect stronger. When a sine wave is played at a high SPL at the right frequency (varies by individual) the diaphragm will resonate and it will be difficult to breathe. Although we were planning to publish a peer-reviewed paper in a prominent audio journal, someone spilled beer on our test notes so that never happened.
     
  16. erikk

    erikk Stunt Coordinator

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    Richard: ROFLMAO!!!!

    I don't know if you are serious or joking but that just made me bust a gut laughing.
     
  17. Frank_S

    Frank_S Supporting Actor

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  18. DanSt

    DanSt Stunt Coordinator

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    Hey, as long as the show was good [​IMG]
     
  19. Wayne A. Pflughaupt

    Moderator

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    Dan,
    Great job EQing your sub. Sorry to hear you’re not completely happy with it, but I think I may know why: Inadequate house curve.
    The thing about a house curve is that how much is needed is room dependent. Primarily, small rooms need more than large rooms.
    Your chart shows a slope of 11dB between 100Hz and 32Hz, which would be a nice curve for a room with a total volume of about 6000 cubic ft. Your room is only about 4000 ft. so you will probably get the bass you’re looking for by increasing the slope from 100Hz to 32Hz by 3-6dB. You’ll have to use your ears to determine how much increase sounds good to you.
    I’ve found that bass sounds more natural if the curve levels off at 32Hz instead of continuing to rise beyond that point; others here have found the same to be true in their systems. A few prefer the curve to continue upward as far as the sub’s response will take it. I suggest you try both methods and see which you prefer.
    You can’t “fake” a house curve by simply boosting at 40Hz, as you’ve figured out. However, you can set a filter on the BFD to easily dial in a house curve. Our fellow member brucek gives the “how to” details at this link.
    Regards,
    Wayne A. Pflughaupt
     
  20. Mark Seaton

    Mark Seaton Supporting Actor

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    Hi guys,
    This elusive "bass drive" which many talk of is an interesting thing to chase. There are a few issues which make its achievement rather elusive. First off, the frequency ranges involved are usually at the top end of the subwoofer's range, and SHOULD include the main speakers upper bass response.
    A common problem is that a distorting subwoofer will normally add to the percieved "drive" as the upper harmonics help to add percieved power to the system. The lower the distortion from your subwoofer, the more critical the upper bass from your mains becomes. I regularly run into this even in our live sound systems with our BassTech 7 which has very little distortion relative to other subs in that market. Careful level matching, integration, and adequate power and headroom in the mains are required to achieve the "bass drive" which most usually can get by just pushing the subs into distortion. The point here is to consider the response of more than JUST the subwoofer.
    Looking at your response curve, and considering your comments, I would first suggest you investigate the crossover region and look for any dips or depressions in the response, along with paying attention to match the levels of the mains and the sub near where they crossover. Realize if you just set your levels using the test noise, you probably have the upper range of your subwoofer below the level of your mains, as the rising response of the subwoofer would cause the "matched levels" to probably be matched in the middle of your curve, leaving the upper bass range depressed.
    I would also like to make a few comments on the suggestions of "house curves." This practice will always be somewhat difficult to get just right, as percieved balance will vary with listening levels. My own suggestion is to aim for a rising response of maybe 3dB/oct. below 50-60Hz(i.e. 50-60Hz equal in level with the upper range). I do enjoy listening at higher levels, but I also have a bit of clean headroom to play with. [​IMG] Now, there are two factors which I believe you should pay attention to in developing your own personal curve.
    First is the extension of your subwoofer in your room. With response that rolls off much above 20Hz, you will probably want a slight elevation somewhere in the 60-150Hz range. Playing with crossover settings and EQ can usually achieve this with a little diligence. Secondly you need to consider at what levels you listen. The lower the normal listening levels, the more you can get away with an elevated low end. As the levels get higher, a flatter response sounds more and more natural. Of course many subwoofers start to distort as the level increases, and distortion products will certainly mess with the percieved balance.
    My take on the curve above would be that it is a bit steep. I would try to maintain the great low end response you have, but shelf up the response above 45-55Hz such that the response doesn't fall below 75-77dB and maintain that level into the response of the mains. Do be attentive to any high-Q peaks in the upper range though, as it is usually percieved to be preferrable to have a slight dip as opposed to a significant peak in this range.
    The multiple settings on the BFD should help with experimentation, so let us know what you find.
    Regards,
     

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