Tempest box too big?

Discussion in 'Archived Threads 2001-2004' started by PaulDF, Oct 21, 2002.

  1. PaulDF

    PaulDF Second Unit

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    Okay, I've had my Tempest sub running now for about a week. It is a huge 360L modified EBS design tuned to 16 hz. It is currently powered by an older 100w/ch receiver. 1 channel to each voice coil. Crossover is at 100 hz(the lowest my receiver will go). For movies, the LFE is amazing... I am quite satisfied there. But for music, it seems a little bit boomy and doesn't pound quite as fast and hard as I might like. Now I assume that this is all to be expected with such a large box, perhaps I've gone bigger than "bigger is better"? What are all your opinions? Would a proper amp help my situation? Or is a smaller box my only solution if I wanted bass better suited for music. Maybe I should have stuck with the Adire Alignment. Thanks.
     
  2. Joe Tilley

    Joe Tilley Supporting Actor

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    My god that thing has got to be huge!!! I have a 270 liter sono & I thought it was damn big. What are the dimensions on that beast.

    BTW for what its worth I am using a Dayton 15" DVC with the PE 250watt plate amp, it is tuned around 17hz with a 6"by 25" port & filled with about 48oz of poly fill. I listen to just about any kind of music form Heavy Metal, & I mean the old fast & crazy stuff to Classic Rock & Rap, & it doesn't matter what I throw at this thing it sounds great. And movies are something of another world I still cant get over some of the bass thing will put out.
    Have you ever thought about cutting it down in size a little?
     
  3. PaulDF

    PaulDF Second Unit

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    It is 24" * 24" and 55" tall, including the 4.5 inch feet. It is rather large but I have the room so what the heck? Looks kinda threatening in a cool way. I figured as long as it performs well enough, I don't care how tall it is. Yes, even though it has only been completed for a week, I had tried to think of a way to lower the volume... How would I do that without massacreing the nice job I did? Wouldn't your stuffed 270L sono be almost equal to my 360L unstuffed? Doesn't that much stuffing fool the driver into thinking its in a box roughly 1/4 to 1/3 times larger?
     
  4. PaulDF

    PaulDF Second Unit

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    I'm hoping for response from sub specialists out there... Okay, what if I left the volume alone, and tuned it to 18 hz. That should increase the response between 17 to 50 hz by 1.5 decibels at the most. It would flatten things out better. At least according to WinISD beta. Tuning higher seems to work better than a lower volume would. I was just worried about unloading the driver if I tuned it higher than 16 hz since I have nil for protection so far. So my question is, how will tuning 2 hz higher affect my sound? Please help!
     
  5. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Tuning it higher and leaving everything else the same will probably add more mid bass punch. It won't clean up the bass but may actually make it boomier. However, since you're only increasing it by a small amount of 2hz the change might not be noticeable.

    I have reason to believe the boomy/inaccurate bass is a result of room modes and resonances that acoustic treatment or equalization can fix. If you notice that some bass notes sound boomy and some notes sound dampened then this may be the cause.

    If what you are looking for is tight punchy bass (HT and rock music like kick drums) then you should have chosen a smaller box/higher tuning. The typical end results with that type of box may be a response hump and loss of bass extension.

    The box you chose gives deep extension, smooth response, and musical bass (Like cellos and pipe organs).
     
  6. PaulDF

    PaulDF Second Unit

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    Thanks Chris, I was definitely going for deep extension, obviously. I wasn't expecting extremely punchy bass, but had hoped for a significant improvement over my little 10 inch sub. I didn't want any particular humps in the freq curve, just smooth overall bass. Perhaps being crossed over at 100 hz might account for some boominess? Until I buy a different amp, I have no more control than that, other than an EQ starting at approximately 80hz in the receiver powering the sub. Should it be set near 0? I can't decide whether its worth shortening the ports, or just leaving well enough alone for now...
    BTW Chris, those tones you linked me to were exactly what I wanted, Thanks! [​IMG]
     
  7. PaulDF

    PaulDF Second Unit

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    Okay, seems I'm talking to myself but oh well. Chris you were right, I'm going to try moving the sub to different locations since I seem to measure large (20 db) differences within the same room. Tonight while playing a CD I disconnected my main speakers just for kicks. The whole house was literally shaking. Funny how its not so noticable when the mains are running. Guess it all blends together.
     
  8. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Paul, It may be your amp too. Have you tried a dedicated subwoofer amp? It made a big difference in my subs sound. The PE amp is a great bargain (usu 99.00 for 270 watt amp)
     
  9. PaulDF

    PaulDF Second Unit

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    Unfortunately I don't have a dedicated sub amp, besides the 150 watter in my previous pioneer sub. I seriously doubt it will be even close to compatible with my Tempest. I have had my eye on a PE amp, but right now my money is being spent elsewhere, as usual.
    I don't know if "boomy" is the right description... Its a pretty vague term actually. Maybe I need to listen to a few other quality subs for a good comparison to my own. And as I said earlier, I hope to move my sub around the room or place it in my listening position and measure SPLs around the room, when I get time that is...
     
  10. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Paul,

    I tried a Sony receiver to power a sub, and then when I got the PE amp, it was night and day. Really. PE sometimes runs them for 99.00, I paid 135 and was happy. I also bought one from Adire, fine amp too...
     
  11. Peter Jessee

    Peter Jessee Stunt Coordinator

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    Paul,

    What are your room dimensions, and where is the woofer located? Do you have it in the corner?

    The first place to try is EXACTLY in the middle of the longest wall. Get out a tape measure and make sure you're dead center. If that's a doorway or other inconvenient spot (are there any convenient spots for a 24 x 24 x 55" box?), try the middle of the other wall. This will eliminate one of the biggest room nodes, and will probably clean up the sound a lot.

    Corners will give you the most room gain, but will also almost guarantee two (or more) big peak/suckout combinations. With your sub, you have gain to burn, so give this a try.

    Peter
     
  12. Allen Ross

    Allen Ross Supporting Actor

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    Let me understand this
    so if I want a tempest to have more of a punchy bass for rock music, NIN, Tool, with great percusion I would want to tune the sub higher say 20-25 HZ, or am i speaking out of my arse?
     
  13. PaulDF

    PaulDF Second Unit

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    My room is about 18 * 24. I will try and explain where everything is situated... My listening position is about center of the room. In front (of course) is the wall of black as my wife calls it. Main speakers about 8' apart. To the right of the right main is the sub. Stuffed in the corner. To the left of the left speaker is a hallway, no door. Direct left of listening position is a woodstove with rock wall. To the right of L.P. is just some chairs and a wall. Behind is a couch and bookshelves and a wall. At back left is another doorway, with door. Ceiling is suspended fiberglass panels. Floor is concrete with berber. Now, I've found that the most bass is heard right beside the sub or left down the hallway, even into the hallway. The least bass is to the right of L.P. along the longest openest wall. Hope this makes sense...
    BTW Peter, does this mean you figure my sub should perform well if properly set up? I really don't want to tear into the box.... Thanks!
     
  14. Peter Jessee

    Peter Jessee Stunt Coordinator

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  15. PaulDF

    PaulDF Second Unit

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    Thanks Peter, I will try it. And where can I find that article again?
     
  16. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    "Let me understand this
    so if I want a tempest to have more of a punchy bass for rock music, NIN, Tool, with great percusion I would want to tune the sub higher say 20-25 HZ, or am i speaking out of my arse"
    Yes a higher tuning will add some punch to the subwoofer and an increase in SPL in the mid bass area. (Adds some mid bass punch to it). When taken to extreme levels the sub becomes a one tone car boomer due to the immense spike in the response. I'd have to play with a box program to tell you how much gain you'll get.
    I know a lot of HT enthusiasts who would disagree with Russ Herschelman because of the free bass gain when placed in the corner. (It's almost like doubling the amplifier power)
    BOOM! baby [​IMG]
    Of course there's standing room modes which is a side effect to corner placement which can be reduced with equalization or room treatments.
    So your room is 18 x 24?
    This calculates to 24hz and 31hz being the frequencies least audible in the listening position, while 47hz & 63hz being the loudest. Put these together and you have one roller coaster of a response.
    What happens if you place the sub in the middle of the 24 foot length is an elimination of the 24hz null. This is because the sub is being placed in the null of that 24hz standing wave therefore canceling it out or simply not energizing the resonance.
    Actually, middle placement might get rid of all odd order resonances.
    This still doesn't do jack for the width modes so You'll still have a dip at 31 and peak at 63 which may actually be more noticeable due to the elimination of the other modes.
    I've been doing lots of playing around at my site. You can also DL a bass tuning worksheet I made.
     

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