Why would anyone want to tune a sub so high???

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

  1. Sebastian

    Sebastian Second Unit

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    I have the HTD LII sub and I ran the volume of the box and the port sizes through LspCad and the box tuning frequency came out to be 48Hz (50Hz in WinISD)with stuffing at 0% and the driver and amp were not taken consideration, just inputted the 44L as the volume.

    Actual specs:
    10" driver
    Internal volume: 44L without amp, driver and ports
    Ports: 2 ports 6"(15.24cm)length 2.75"(6.985cm)diameter, flared on both ends.
    There is some stuffing in the box.

    The sub is rated down to 30Hz +/-3dB, is this even possible with a sub tuned at 48/50 Hz?

    Doesn't a sub freq response drastically fall off after the enclosure tuning frequency?

    Can someone explain why would HTD or anyone else would tune a sub so high?
     
  2. Jeff Meininger

    Jeff Meininger Second Unit

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    My HTD level 1 sub is also rated to 30 Hz. I'm no expert, but I _seriously_ doubt I get down to 30 hz. I don't think the HTD subs are rated 100% correctly. Don't get me wrong, I think HTD is a great company. Excellent customer service, and the price/performance of their main speakers is GREAT. I'm extremely pleased with the performance of my level one mains considering the price I paid. Heck yeah I'll upgrade one day, but for a budget setup they really sound nice.

    There's also the idea of the sub using EQ to get lower. Below tuning, you're fighting a losing battle against cone excursion, though. Perhaps under a certain SPL level you can get to 30 Hz -3db, but above that SPL level there might be an excursion limiter? I don't know what kind of circuitry that would involve, but it might be possible.

    C'mon UPS man... bring me my Shiva!
     
  3. Sebastian

    Sebastian Second Unit

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    Actually when talking with one of the HTD reps he indicated to me that all their speakers are rated at +/-3dB.

    If anyone is wondering I do not have the actual specs on the driver itself.
     
  4. VinhT

    VinhT Second Unit

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    It's not that they want to tune it that high, it's merely a compromise to fit the port tubes in the small enclosure. You can definitely use smaller diameter ports to tune the sub correctly, but there will be quite a bit of port noise at high volumes. So, just bump up the diameter of the ports. But then that requires a much longer tube to get the same tuning, which won't fit in the box.

    Solution: Cut it short, resulting in a high tuning point, but at the same time giving it a huge peak in the 45Hz region.

    Result: The small box is very appealing to potential customers, and the boost in the response of the sub sounds great to the untrained ear ("Woah, this sub slams!").

    As for the response of the sub being rated +/- 3dB... nope. I don't think there is any subwoofer maker that actually divulges the real designed F3 of the sub. I'm pretty sure "typical room gain" is factored into that to make it look more impressive. Sure, the sub will actually respond at 30Hz, but it'll be more like it's F9 or F12 point rather that only being 3dB down. Unless of course, equalization is being used. But with only a 150W plate amp, that would really limit the overall output of the sub.
     
  5. Sebastian

    Sebastian Second Unit

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    If that is the case about port length, why didn't they just use one port and have tuning freq in the lower 30Hz?
    Or would that most likely cause port noise in the process?


    Looks like they failed at their objective then, because those words never cross my lips when I hear it play.
     

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