Speaker Buffs: more advice please

Discussion in 'Amps and Cabs [BG]' started by Rockin John, Mar 19, 2002.

  1. It's been suggested to me that I could brighten my sound by adding a couple of 8" drivers into the system. So, to go with my Eminence Delta 15 (currently in an undersized box!) I'm considering a pair of Eminence Alpha 8MRs built into a separate box.

    These units would be series connected then paralled with the 15" to present about 5 Ohms to the slave amp. That would then run 200ish Watts into the load.

    The questions are:-

    Will this scheme help brighten my sound?

    How would I choose the correct crossover (assuming I require one)?

    The 8MR is described as having a closed chassis thus not requiring another enclosure. Does that mean the box volume is unimportant for these drivers?

    Hope someone can advise.


  2. Without a crossover, the bass frequencies will destroy the small drivers.
  3. How do I decide on what type and frequency of Xover to use?

  4. Go out to the Eminence site and look up your 15" driver. Check the response curve and notice where it falls off. Typically 1500 ~ 2000 Hz. Cut this value in half (1 octave) and use this as the highest crossover point.

    If you want to use a canned Eminence crossover (www.partsexpress.com) look for 250 Hz or higher.

    250 Hz will keep all the fundamental in the 15" driver, and most of the harmonics in the smaller driver. It will help if the SPL value is close for both.
  5. Hello Bruce and thanks so far:D

    The Delta 15 is quoted as having a useful frequency range of 40 Hz to 4k Hz. The Alpha is 500 Hz to 5k Hz. Obviously both units have a response above and below the quoted useful range.

    Eminence make a number of Xovers but I've found 2 that seem to fit your advice:-

    1) 250 Hz, Low Pass
    2) 500 Hz, Low Pass

    Which of these is suitable, please?

  6. Here's another thought. Am I wasting my time (and ultimately money) looking into this possibility? Eminence's data sheet says the Delta 15 is good to 4k Hz, and that the Alpha is good to 5k Hz. So is there really any point in spending about £100 for that extra 1k?

    I know many rigs use various combinations of speaker size. But many just use one size; say 15".

    Having said that I could get a couple of piezo horns running from 2k Hz upwards, and at a fraction of that £100.

    Any more wisdom, please.....?

  7. Piezo ain't very hi-fi, but they are inexpensive and do not require a crossover. If the Eminence will go to 4 KHz (I think not) that would be great. First thing is to try the piezo without spending other money.