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Making a crossover. Help!

Discussion in 'Amps and Cabs [BG]' started by jock, May 2, 2005.


  1. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    I have a really nice Glockenklang UNO 1x15" cab. Id like to ad some highs to this cab by adding a Beyma 605Nd mid/high driver in a separate box. I think I will go with a second order filter but how do I choose the crossover frequency? Do I need to have a lowpass filter for the 15" or is it enough to use a high pass filter for the 6" ?
    Please help. Im quite new to this but I have read as much as I have found about this. Here is a link to the mid driver:
    http://profesional.beyma.com/ENGLISH/detalle.php?id=110

    A similar cab by Hevos with a 15 and 6 crosses over at 2500Hz but I thought that sounds like too high on paper and I dont know wich order they use. :confused:
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    It's difficult to say for sure without T/S specs, but the implied f3 of 150Hz would indicate that a crossover at 150 or higher is OK. I'd cross over at the point where the 15 can be expected to start beaming, and that would be about 800 Hz. Stay away from second order, as that is prone to phase difficulties. I'd run 3rd order HP on the six. I would use a 1st order LP on the woofer as well for a proper impedance load and to divert high frequencies that the 15 can't properly reproduce into the 6. You can get your component values here: http://www.lalena.com/audio/calculator/xover/
     
  3. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Thanks!
    The 6´s TS parameters are in the links PDF file.
    Anything special I should consider when choosing components? I see big difference in prices between caps and caps etc.

    Also should I use third order Bessel or Butterworth filters?
     
  4. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Either would do, but the 2nd order filters may require that one driver be wired out of phase, and if you don't have RTA gear to check the response you won't know. I don't think the filter type is all that important in MI usage.
     
  5. With each order of crossover you get 90 degrees of phase shift don't you? 2nd order would be 180 out and wiring one driver out of phase would compensate, but 3rd order would be 270 out of phase and just reversing one driver wouldn't correct it. Am I understanding this correctly?
     

  6. Check Parts Express
    I like the "Perfect Layer TM" coils and if you want really low internal noise caps the Kimber Kaps are awesome but significantly higher in price than the Dayton Audio.
    Not a lot of difference in sound between Kimber Kaps and Dayton Audio except they are as previously stated, lower noise and lend sort of a more spacial sound. You would have to A/B them together one after the other really. Are they good? Yes, Very good, are they worth the difference? That is subjective. I prefer them and they are better but cost difference worth it??? In the case of the crossover I built the Daytons would be around $6 for the two while the Kimber Kaps $25 for two.
     
  7. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Not quite. 2nd order is 90 degrees out, and the combination of two filters (HP & LP) results in 180 degrees of shift, which sometimes requires reverse phasing of one driver, but not always, as the time-aligning of the drivers can also affect phase at the crossover frequency. Using all 4th order L/R filters gets around this while using even order filters, but most woofers don't require 4th order LP, so you're wasting money on the parts count. I like using odd order filters, either 1st LP/3rd HP or 3rd LP/5th HP for maximum protection with minimum parts count and no phase worries.
     
  8. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I've had my eye on that driver. It's actually 6.5 inches instead of the 6 inches suggested by the name. I only mention it so you can make sure it will fit.

    Can you post a review of the speaker once you get it running?
     
  9. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Hi Petebass. I downloaded the PDF for the driver so I have the exact dieameter of the driver. I might go for the Beyma 6MI90 in the end as it costs less and the 605nd is actually based on that driver.
    Im currently working on the cab and how to make it practical and visually pleasing. It´s gonna be areally small cab. Can I put the 15 on the floor, my amp on that and than the 6,5" on top of that or do the drivers have to be as close as possible to each other?
     
  10. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    They are actually quite different in the specs.

    The 605nd has an FS of 150Hz, likes a cab of a bit over 1 litre, and doesn't do much below 250Hz. I'd cross it over at 500Hz or higher. That cab is so small, I even wonder how to fit a 6.5 inch speaker into it. You could probably even incorporate it into the Glock. Robbing the 15 of a mere 1 litre will barely affect it at all.

    The 6MI90 has an Fs of 120Hz, prefers a bigger cab at 6 litres (still very small) and has an F3 of 120Hz. Of course this lower response is at the expense of sensitivity. The 605Nd will be louder, so it depends on the sensitivity of the Glock 15 as to which one would blend better.

    Also, the 6MI90 tries to go a bit lower but both have the same X-max(1mm). Realistically I don't think you could ever really use any of that extra lowness, so you'd still be crossing over somewhere near 500z, but at a reduced output. I'd lean towards the 605Nd if it were me.

    If you're trying to save money you should also look at the Eminence Alpha 6 or even the Alpha 8.
     
  11. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    Yes, the Alpha 6 would definately be cheaper but would it sound as good as the 605nd?

    Right now I consider cutting a hole in the Glockenklang to ad the 6,5" in that cab. How much would this degrade the second hand value of this cab? I got it used at a great price and Glocks are not as expensive here as in the US.
     
  12. jock

    jock

    Jun 7, 2000
    Stockholm, Sweden
    I´ve changed my mind again. :D
    I was tryinng to see where to put a 6" speaker into my Glockenklang 1x15 but it will not fit. A 4" or 5" speaker is maximum what will fit on the baffel.
    Most speakers in that size are HiFi speakers that are really inefficient so now I think a good tweeter would work best. Where do other 1x15 + tweeter cabs cross over? Seems there would be quite a dip in the 1000-4000Hz range. It might be fine that way but is there a tweeter that you can reckomend that goes as low as possible. Maybe a 2" tweeter as in this cab: [​IMG]
     
  13. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    The danger her is that using horns to go low can sometimes result in a sound that's a bit nasal. The question is how high that 15 goes? The website says 36Hz to 3.5K, which means that 15 defies the laws of physics..... I suppose everyone else bends the truth on frequency range specs, so Glock would be at a disadvantage if they suddenly started being too honest.

    Most 15's with any sort of low end capability will give up at 1.5K or thereabouts. Most bass cab horns will kick in at 3K or therabouts, so a hole in the frequency range is going to be virtually unavoidable.

    I like the Peerless 811647 Silk Dome Tweeter. They're not expensive and being silk they sound smoother than conventional horns. I made 2 crossovers for mine. One is 2.5K and the other is 3.5K and as mentionied earlier, the 2.5k crossover exhibits a small amount of nasal-ness that doesn't appear to be there at 3.5K, but it's but not enough to worry about. Plus at 3.5K, it feels like the tweet is a little too disjointed from the rest of the speaker, so I ended up using 2.5K. And at 2.5k the hole in your freq range will be pretty small, certainly smaller then most 15+horn cabs. But for this to work without blowing up the tweeter, you'll need a 4th order crossover. I wouldn't recomend any less, especially at 2.5k. Don't worry they're not expensive or difficult to make.

    I once used a Motorola (I think they call themselves CTS nowadays) KSN1188 piezo horn which goes down to 800Hz. It was surprisingly good for a piezo, but it's not as cheap as you'd expect a piezo to be. I also found that it worked best with a crossover, even though piezo's don't technically need one.

    There are also a miriad of P.A type horns that will get you down to 1k or 1.5K. They all seem to be too big and heavy for a bass cab, but I must admit I haven't investigated this avenue too deeply. The one I really like for PA is the RCF N252N. There were a few occasions where I heard a PA in action and thought, "hey I like that horn" and it turned out to be the RCF N252N. I don't know much else about them but it might be worth checking out.

    What about Glock? Wouldn't they be able to sell you one of their horns?