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3015 DIY questions

Discussion in 'Amps and Cabs [BG]' started by Johnny Mack, Mar 11, 2009.


  1. hello peoples.

    i currently have an eminence 3015 in a 2.67cu.ft. box tuned somewhere in the vicinity of 50-60hz. using winISD i call it 55hz.

    i have been curious about building a new box for the driver. i am calculating 3.32cu.ft. into a box tuned to 45hz.

    modeling the two against each other, i gain maximum power in the 40-50hz range (compared to only 150 watts at 40hz in the old cab) and hit xmax at 35hz rather than 40hz using the new cab.

    again, modeling the two, the response in the new cab is about 1-1.5dB less in the 80-100hz range, but about 4dB more at 40hz and about 2dB at 50hz.

    thinking the extra cu.ft. will help cone excursion and prevent frying the speaker at 40hz, is this the right path to take?

    is the gain in 40-50hz bass better than the loss in the 80-100hz?

    other than what i have posted, what else can i look at?

    is someone kind enough to model these two together to double check what i have listed?

    btw, i am giving the speaker 170 watts.

    thanks for any response.
     
  2. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I've used this driver. There's nothing to gain by trying to extend the LF -3dB point by using much over 3.0 cf since the driver will just run out of excursion that much quicker. If you desire both bass extension and power handling consider a two-way design with 3015LF and a mid cone. Check sig.

    EDIT: I know you are only using 170 watts right now, but once you start boosting bass EQ to compensate for a larger box/lower tuning as an attempt to fill the low end you will likely think a 52-55 Hz tuning works better for you.
     
  3. i do like the sound in the box it is in, but at times worry about over excursion in the low low range. i know it's xmax is pretty good, but i tend to cut bass EQ a tad, moreso because it sounds better.

    i'm kinda confused, are you saying that with a bigger box it will run out of excursion quicker? or because it is possible i will be boosting bass EQ? this doesnt really make sense to me.

    i guess the purpose of my idea was not necessarily to extend LF, but to protect the speaker better, the extra LF just seems to come along with it. that doesnt seem to sound right either, but im just going by what winISD is showing. thanks for the help!
     
  4. fast slapper

    fast slapper

    Dec 11, 2001
    Fresno, CA
    Have you experienced any actual problems?

    If you like the sound just keep the way it is. I don't think you have enough power to do any real damage while keeping the amp in its clean operating range. I've pushed mine pretty far with no consequences. Great driver.
     
  5. DukeLeJeune

    DukeLeJeune rational romantic mystic cynical idealist Supporting Member Commercial User

    Nov 24, 2008
    Princeton, Texas
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    Johnn Mack, I think you're better off with the smaller box and higher tuning, as it's giving you more output where you need it most. Given that the fundamental is going to be at least 6 dB down relative to the first harmonic, 150 watts excursion-limited power handling at 40 Hz is plenty (for a four-string, anyway).

    All else being equal, a larger box will have lower excursion-limited power handling. But changing the tuning frequency means that all else is not equal.
     
  6. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Yeah. When you model this stuff you need to look at the other graphs too. Max power, max spl, cone excursion.

    But to keep this simple tuning the 3015 to like 45 Hz is just throwing output away. Putting it in a box much more than 3.2 and a 52-55 Hz tuning is wasting what it does well. If you are looking at bigger boxes and lower tunings you have the wrong driver.

    If you were actually using high power and playing a low-tuned bass and wanted protecting from "unloading" you'd simply roll off low EQ or use a highpass filter.
     
  7. okay, i get the general consensus here, thanks everybody. i have not experienced problems, just more of a curiousity. as said before, i was just a little concerned about overloading the driver at low low frequencies, i typically cut them a little anyway, so i guess it's no big deal.

    i use two of these speakers in an old peavey 215 and throw 300 watts at them, but if put in single boxes, using only one, it would see about 170 watts. i do like the sound of these speakers, very excellent. i guess i wont change a thing!

    thanks again!
     

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