Need help. Can these drivers really exist? Their specs are simply too good to be true

Discussion in 'Archived Threads 2001-2004' started by Javier_Huerta, Dec 2, 2002.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    One look at the specs tell the story
    HED-10DVC
    SPL: 88 dB
    Fs (Hz) : 24 Hz
    Qts : 0.669
    Qms : 13.867
    Qes : 0.703
    Vas (l) : 75.41 l
    X-max : 12 mm

    HED-15DVC
    SPL: 90 dB
    Fs (Hz) : 20 Hz
    Qts : 0.607
    Qms : 11.473
    Qes : 0.641
    Vas (l) : 332.64 l
    X-max : 17 mm

    If you simulate these drivers under WinISD for a sealed box, be ready for a surprise. The things are ruler FLAT. Amazingly so. I can't believe their response. True, their boxes are a bit on the big side, but the 10"'s curve can be excellent on a 80 liter box, and the 15" needs a 250 liter box.

    What do you think? If I build a sealed box with these drivers, will I really get that kindof performance? Seems too good to be true to me... More so if you consideer the drivers cost around $85 (for the 15").

    Thanks!
     
  2. Shawn Solar

    Shawn Solar Supporting Actor

    Joined:
    May 12, 2001
    Messages:
    763
    Likes Received:
    0
    With a QTC=.607 I would think that I would go sealed. It's funny that the 10" has a slightly higher QTC. I would do the 15". the 10" is far better suited in the car.
     
  3. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Shawn, I actually think the 10" would be a terrific driver for a small minimonitor system. It seems to spec beautifully. But the 15" will be my driver of choice for my HT and music system. A pair of them with 275W will surely rock the house.

    Why do you think the 10" is better suited for the car? I get from WinISD huge boxes for flat frequency response.

    Thanks!
     
  4. Hank Frankenberg

    Hank Frankenberg Cinematographer

    Joined:
    Oct 13, 1998
    Messages:
    2,573
    Likes Received:
    0
    Javier, what brand are those drivers?
     
  5. Shawn Solar

    Shawn Solar Supporting Actor

    Joined:
    May 12, 2001
    Messages:
    763
    Likes Received:
    0
    Hank,
    I believe they are cerwin vega. I think that by porting the box it will pt the qts of the system too high. Mind you I haven't modelled them yet but looking at the 10" with he low vas and high Qtc and realitively higher fs value that it would be better suited for a sealed box. If thats the case the 12mm of x-max would not be enough to push decent spl. So it is better suited for the car.

    The 15" would be alright in a ported but would need a huge box. I will model them later tonight.
     
  6. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Shawn, they are indeed C-V's. Both drivers work beautifully in sealed boxes, but they need to be really big.
    As for venting the enclosure of the 15", it's out of the question. The box needs to be huge, although extension goes right to 15 Hz ruler flat. It works a lot better in a sealed enclosure, but again, in order to keep Q in control the box needs to be big.
    You really don't know how easy you have it living in the States, and having so many drivers to choose from. All we get here are tons of very bad drivers and a couple of semi-decent ones (CV falls in this category) I was about to buy a Vega 154, when the dealer told me they were out of stock. They offered me to exchange it for a pair of HED-15DVC and a refund, but after modeling the box, I see there's no way I can make a 1,500 liter box for one of them to get a Q of 0.707.
    I think I'll go with their 12" model, which seems to behave a lot better in ported enclosures, and will build the 10" for a small minisystem (I'm sure it being sealed will give a very nice, accurate sound).
    Oh, well. Back to the drawing board. [​IMG]
     
  7. Shawn Solar

    Shawn Solar Supporting Actor

    Joined:
    May 12, 2001
    Messages:
    763
    Likes Received:
    0
    I'm a Canadian. Sorta in the same boat as you. I gotta double the price for Canadian dollars[​IMG]
     
  8. Bill Leber

    Bill Leber Stunt Coordinator

    Joined:
    Aug 25, 2001
    Messages:
    133
    Likes Received:
    0
    Do you have space for an IB? Get 4 of the 15's and you might have something!
     
  9. RayJK

    RayJK Stunt Coordinator

    Joined:
    Nov 25, 2002
    Messages:
    131
    Likes Received:
    0
    An IB for these seems interesting, are there any guidelines for the column size? For a standard setup (Bass reflex, sealed, bandpass) there are a number of programs to use that will get you in the ballpark for box size, is there anything similar for IB computations or isn't this needed? Just new to DIY and looking for a clue.
     
  10. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Jack - Thank you very much for your kind answer! I must say I now undersand more what the Qms and the Qes represent in real life.

    I'll keep on looking for a good driver - meanwhile, I now have more information about what makes a driver "good".

    Thank you, again, very much.

    Javier.
     
  11. Dave Milne

    Dave Milne Supporting Actor

    Joined:
    Jul 2, 2001
    Messages:
    568
    Likes Received:
    0
     
  12. Javier_Huerta

    Javier_Huerta Supporting Actor

    Joined:
    Mar 9, 2002
    Messages:
    619
    Likes Received:
    0
    Oops... thanks for the tip, Dave!

    Bill, I was wondering, are there any articles I can read about building IB columns? Maybe I can try and do such a thing... I find the designs very interesting.

    Javier.
     

Share This Page