Passive radiator tumult for music applications

Discussion in 'Home Theater Projects' started by KaronnyF, Jul 5, 2004.

  1. KaronnyF

    KaronnyF Auditioning

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    Can a passive radiator design on the tumult be used effectively for music apps? Considering PR designs has even more group delay than ported designs, is that a concern?

    maybe someone may like to offer their experiences if they heard one [​IMG]
     
  2. John E Janowitz

    John E Janowitz Second Unit

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    Group delay peaks at the tuning frequency. If you're tuning below 20hz, then it will not create any issues. PR's are typically used only when an adequate port cannot be used anyway. Take a Tumult, put it in a 5cf enclosure and try to tune to 18hz with a port and it just can't happen. You'd need a minimum of a 6" diameter port, and that would be around 43" long. Just no way to fit it in the box.

    For some reading on PR's: http://www.stryke.com/prfaq.htm

    John
     
  3. Rory Buszka

    Rory Buszka Supporting Actor

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    With the AV12 and 500 watts in the Thunder 12.3 cabinet (dual 15" Stryke PRs) I still run out of passive radiator excursion at 20 Hz when I use a test tone. I wonder how the Tumult+PR enclosures fare at their tuning frequency.
     
  4. David_P

    David_P Stunt Coordinator

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    I heard Craig Woodhall's tumult/dual 18" PR, 24" cube, 1600gr PR's probably tuned to 19-20 hz or so.

    I would characterize it as almost analytical, if a sub could be called such. I brought along quite a bit of classical music, which Craig doesn't listen to normally. Very tight and controlled sounding. I thought it was possibly somewhat "light in the bass", until he cranked on some movies and stirred up my innards doing it [​IMG]

    It was the best of both worlds, tight and unobtrusive and very deep and potent at the same time.

    David
     
  5. KaronnyF

    KaronnyF Auditioning

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  6. Dan Hine

    Dan Hine Screenwriter

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    Karonny,

    You are aware that Craig Woodhall who was mentioned above is NOT the same as Craig Chase who has a PB2+, HSU VTF-3, etc. Yes? Or did the two of them somehow get together?

    Oh, and you can't really undermine anyones opinion since they are, afterall, opinions. [​IMG]
     
  7. KaronnyF

    KaronnyF Auditioning

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    ooops didnt know that
     
  8. Michael R Price

    Michael R Price Screenwriter

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    It wasn't because the Tumult has more low bass? Or were the subwoofers individually equalized?
     
  9. KaronnyF

    KaronnyF Auditioning

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    The impression I get is that the denali has more impact in the freq region below hearing.
     
  10. James W. Johnson

    James W. Johnson Screenwriter

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    Yes it was answered to his desire as far as I can tell. [​IMG]
     
  11. Jack Gilvey

    Jack Gilvey Producer

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    My point exactly. And it's incorrect to say that only by comparing a sub to other subs can one evaluate it...one can use actual live music (imagine that!). Comparing two completely different subs and assuming any perceived difference is due to the presense or absense of PR's is folly. PR's have slightly more GD than ports, but both have much more GD than sealed...yet somehow ported subs manage to be supremely "musical"? Seems there's more at work here than GD.
     
  12. David_P

    David_P Stunt Coordinator

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    Craig Woodhall and Craig Chase are not the same person [​IMG]

    my take:

    most of the music we listened to did not go below the tuning frequency of the PR's... ergo, I think the tautness of the bass I heard I would chalk up to the inherently low distortion of the Tumult, and the fact that the sub was operating above the frequency range where group delay might be an issue.

    This combination still did incredibly well in very low bass in HT... we listened to the Haunting (DTS), Private Ryan (DTS), Finding Nemo, LOTR:FOTR (opening battle scene, DTS).

    The haunting was probably the lowest bass and literally pressurized the whole room.

    I "think" that a low distortion (low BL) designed sub like the Tumult coupled with a very low tuned box with PR's is perhaps the best of all worlds... you get low group delay well above the tuning frequency, where most of the music bass you'd listen to is, and staggering output down low in HT where group delay is perhaps not such an issue. You get an overall well-rounded sub.

    I only wish Craig had installed the extra 900g weights so I could hear what a 14.5hz tuned Tumult sounded like [​IMG]

    He has them, showed them to me, just never installed them cause he like how it sounded as is.



    David
     
  13. KaronnyF

    KaronnyF Auditioning

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    Thats what I thought as well, but then theory and practical doesnt always come together.

    David, Did you have any reference in which to compare the PR sub to at the time? I.e. Headphones, another sub,etc
     
  14. David_P

    David_P Stunt Coordinator

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    on the back of those PR's (Stryke 18") there's a tube. The extra weight is a cylinder of metal about 2" long that would slide into the tube from behind. The weight kit came with gorilla glue (I think) with which to glue it in.

    You can order the PR's at the correct weight (2500gr vs. 1600gr) as well.

    Reference...

    I've heard a number of subs. Velodynes and SVS for commercial, Ev-30 in fridge-size slot/corner loaded sealed cabinet (lowest SAF sub I ever saw... imagine a 23 cu ft fridge with a top freezer and saw the freezer off... that what the cabinet was), tempest in 21"^3 cabinet tuned to 20 hz with PE 250 w plate amp...

    The Velodyne (12") and SVs (forget model number) were ok, although the SVS was was more impressive.

    The EV-30 was freakishly efficient and very very tight. It also obvious rolled off somewhat below 30 hz but still had reasonable output down low due to room gain i guess. First sub I ever heard that made my vision blur.

    The Tempest was built by Al Wooley (RAW) and sounds very good... the owner is very pleased and uses it mostly for jazz. It doesn't do the extreme sub-20hz stuff real well. Sounds good on music to me, but somewhat boomier and muddier than the Tumult or EV-30. Not so it's not great sounding, it's just more HT-oriented I think.

    The Tumult sounds very very close to the Ev-30 to me... the kicker is the 24' cube vs the fridge-sized cabinet [​IMG]

    The tumult seemed more potent down very low (Haunting DTS for example) and just as tight sounding up where most musical bass is. It also requires loads of power whereas the EV-30 was driven by a 130w amp, which was only lightly used.

    I would strongly suggest you check out an DIY audio clubs in your area and see if you can find someone who built one of these... I was lucky enough to find Craig who lived on 10 miles away or so, and he was kind enough to be willing to show his sub off. The EV-30 belonged to a work-mate who sold it a few years back.

    David
     
  15. KaronnyF

    KaronnyF Auditioning

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    thanks for your report DavidP.

    JGilvey I beleive you have a PR system as well. How does that sound musical wise?
     
  16. Richard_M

    Richard_M Second Unit

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    KaronnyF

    Although I have no experience with PR subs, I have a ported Tumult tuned to 15Hz, although it only has about 70+ hours up it is sounding very very good.

    My listening habits are 30% HT /70% Music

    I have been told by a couple of sources now that it will require at least 200hours to properly bed down. I am going to leave it for a few more weeks before doing any in room freq sweeps and EQ, as it stands now it is performing exceptionally well on both HT & music. BTW most of my music listening is DVD-A and music DVD's, I rarely listen to 2ch much these days as I now prefer the multichannel concerts.

    I am sure you will be happy with the Tumult driver whether you go PR/Ported/or sealed.

    Dick
     
  17. KaronnyF

    KaronnyF Auditioning

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    Are you the same guy who posted up pics and plans of his ported tumult in the OCAU forums?

    If so, man thats some crazy shit I can never do soemthing that complex.
     
  18. Richard_M

    Richard_M Second Unit

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    No I am not guilty of any such thing [​IMG]

    I am just a simple bloke with simple tastes...

    [​IMG]
     
  19. KaronnyF

    KaronnyF Auditioning

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    wow how big was your enclosure?
     

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