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My Frequency Response

Discussion in 'Subwoofers' started by Adrenochrome, Apr 13, 2005.

  1. Adrenochrome

    Adrenochrome
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    I am just about to bamboozle myself with my BFD that i bought a couple of months ago so any help would be greatly appreciated :lease:

    The dark blue line is before equalisation the pink line is nowt to do with me as i have still to fiddle about with the BFD :eek:

    How good or bad does it look prior to equalisation?

    Adrenochrome.
     

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  2. eviljohn2

    eviljohn2
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    Looks like a good start to me mate. :thumbsup:

    Just a couple of starting points: Are you using the RatShack SPL meter? If you're not then the correction values incorporated into that spreadsheet are unfortunately useless. Also make sure that you took the readings with your main speakers running too.

    Assuming all of that's OK then I would consider a fairly wide filter centred around 50Hz. Start with a narrow one then gradually make it cut more until you have cut a wedge out of the middle, then you can increase the bandwidth to encompass as much as necessary. Unfortunately it takes ages (actually, I'll PM you tonight with some other advice). Once you've done that satisfactorily then really it's up to you how far you go with it - the peak around 89Hz could also use a bit of work. Do you crossover your amp/speakers at 100Hz? :)
     
  3. Ian J

    Ian J
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    Could you keep your advice on the forum please so that it is of use to everyone - thanks :)
     
  4. bob1

    bob1
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    Whats the sub? is it a velo vx10, mine did nothing below 25hz and started the down hill climb below 36hz the claimed bottom end of the velo,of cause i'm only guessing so please correct me if i'm wrong.
     
  5. bob1

    bob1
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    Just a point i would do it with speakers off as well as on, i messed around with a peak for ages only to find out it was a peak from the speakers that was causing it and not the sub.
     
  6. eviljohn2

    eviljohn2
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    It's certainly worth trying both (if you can be bothered plotting all of the results again :eek: ) as long as people remember that we're trying to treat the low-end response of the system as a whole rather than the sub in isolation. :)
     
  7. Adrenochrome

    Adrenochrome
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    Hi Bob1 yes it is the VX-10
     
  8. Adrenochrome

    Adrenochrome
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    I Am using a Radio shack spl :smashin:

    Can you please tell me how wide a filter at 50hz you would try (i have tried2) and i still have a large peak.

    Adrenochrome.
     
  9. bob1

    bob1
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    How big is the peak now, you should see it come down as you make the cuts with the bfd.

    Here's your graph,as it was.

    [​IMG]
     
  10. recruit

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    I would try approx 12db cut and Bandwidth 4 for the 50hz peak and see how that comes down.
    Thats quite a nice response you have there. :)
     
  11. shodan

    shodan
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    Looks fine to me as it is! Doesn't a lot of music and movies have the "slam" factor ot 40hz to 50hz? If so then your freq. response is boosting it where it needs it most!
     
  12. Adrenochrome

    Adrenochrome
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    Here is my before and after the blue being the before.

    I Have applied a 15db cut with bandwidth of 10
     

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  13. eviljohn2

    eviljohn2
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    Looking very very good mate - that loft is making life very easy for you! Maybe add a smaller and narrower cut around 40Hz and another around 89Hz. There's no point going overboard as you simply won't notice small changes - a good test is to play a slow frequency sweep through your system so you can hear that the volume stays reasonably flat throughout. :)
     
  14. bob1

    bob1
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    This is the new graph.


    [​IMG]
     
  15. micb3rd

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    That looks like it has lost loads in the 16-22hz region.
     
  16. bob1

    bob1
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    I doubt it had any in that region in the fist place.

    Take a look at my old graph, i couldn't get a real reading below 25hz,don't forget the bottom end of the sub is 36hz you can't expect it to get down that low with real levels.

    [​IMG]
     
  17. Ian J

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    Ignoring the freudian slip in the typing department I would guess that having seen some photographs of Adrenochrome the SPL meter was probably picking up the sounds of his stomach rumbling as he hadn't been fed for 15 minutes.
     
  18. Adrenochrome

    Adrenochrome
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    Cheeky :censored: :laugh: I hadn't been fed for 25 minutes actually :eek:
     
  19. rags

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    Adrenochrome - your original response looked pretty solid as it was !! No significant troughs and a potentially desirable peak at around 50Hz.

    I originally made the mistake of applying too many filters and tbh you cant really hear significant differences in the middle of a movie unless the filter is more than 5db. The most I would do with a graph like that is apply only filter at the 50Hz mark (maybe 5db) plot the graph again and if everything materially remains the same as before leave the rest as is. At the moment you seem to have way too many filters and I am not sure what they are achieving (assuming they are all yours!)
     
  20. micb3rd

    micb3rd
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  21. JBL 4645

    JBL 4645
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    The rumble in the tummy is the infersSonics? 7Hz; :oops: Mate that’s where you home cinema should go to, but be careful as infersSonics can be dangerous if played at very high SPL?

    So it’s not to, difficult to EQ it and always use cuts don’t boost the frequencies… :lesson:

    I am a Former cinema projectionist. :)

    Ashley…
     
  22. Adrenochrome

    Adrenochrome
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    I wonder why ;)
     
  23. Mroizouk

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    :D
     
  24. bob1

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    How is it going with the bfd ,have you settled on a setting and does it sound better.
     
  25. Adrenochrome

    Adrenochrome
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    Hi Bob,

    I haven't had the time to do anything else with the bfd yet :( but to answer the question "does it sound better" in a word absolutely definitely yes :D

    Adrenochrome.
     
  26. bob1

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    It took me ages to do mine ,trying to fit it into normal living is quite a task,after 5mins the wife was saying "are you still messing with that thing".
     

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