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X-Over Design Help

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  • Wolf
    replied
    That's where all those Wilson Watts went....
    Wolf

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  • AEIOU
    replied
    Originally posted by Wolf View Post
    A zobel is not enough for breakup suppression. For the RS125, you really need the LC trap to kill it, and possibly the tank too. The ND25 favors a 2.5k minimum xover, and sounds better above 4k.
    Later,
    Wolf
    Yes, definitely use Tank Traps!
    Click image for larger version  Name:	Tank Trap.jpg Views:	0 Size:	119.8 KB ID:	1447343

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  • Wolf
    replied
    That's a tank, Chris, not the trap LC-shunt I'm referring to.
    Wolf

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  • Chris Roemer
    replied
    You could always have the "trap" components on-hand if needed.
    A pair of 4ohm resistors and a pair of TINY caps: 0.10 or 0.22uF (a 0.15uF would be best, but PE doesn't carry those). You COULD get 0.16uF by using a series string of THREE 0.47uF caps (on each tank).

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  • Wolf
    replied
    A zobel is not enough for breakup suppression. For the RS125, you really need the LC trap to kill it, and possibly the tank too. The ND25 favors a 2.5k minimum xover, and sounds better above 4k.
    Later,
    Wolf

    Leave a comment:


  • Cash51
    replied
    I certainly am not discouraged in any way, simply a very busy weekend.

    I much prefer the fun of testing your own skills at building than buying something - one can easily overpay for what (in times past on this board) often has been shown to be a low quality commercial product, built with inferior materials, but guised with a "famous" name.

    I will post the pics as this begins. I may begin with the crossovers as opposed to the boxes and I've learned the hard way that, in this hobby, patience is as valuable as a Dremel.

    One question to Chris - am I correct that that design would not change if I decided not to port these speakers? (I recognize that this would drastically change the low frequency response - sealed box likely will put the F3 on them around 100Hz). I have not calculated the sealed box size as of yet.

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  • Kornbread
    replied
    Originally posted by Cash51 View Post
    Asking if anyone can provide an x-over design using the Dayton RS125-4 and ND25FA-4...this will be a little 2-way for a small bedroom. Thank you in advance!
    So many times someone joins the forum and posts the question of which 'off the shelf' crossover to purchase thinking building a speaker is as simple as matching crossover freq., nom. ohm, and efficiency of the drivers. Simply build a box and throw em' in. It's way more complicated than that and as the thread-count increases in posts and complexity, going down the rabbit hole to speak, the op gets discouraged and gives up. You came here with the knowledge that this was not the case so you have started on the right foot. IMO, it's much more rewarding to home brew than buying a manufactured product, and if it performs at or above your expectations, or even above that which you would have purchased; bonus points = bigger grin.
    Don't forget to post your adventure or be afraid to ask more questions.

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  • tvrgeek
    replied
    Originally posted by Chris Roemer View Post
    0.15cf box w/a 1.5"id by 8"long port will do 60Hz. Will take 20w to 50Hz, which is 100dB.

    3rd order HP w/"L-pad" attenuation: 8uF series cap, 0.15mH shunt coil (to grnd - #20 good here), 25uF series cap (npe), "L" = 2n(ohms) for SR(series resistor) / and 4n for PR. (normal polarity is "indicated"). Fc near 3k (tweeter Fs is 1.5)

    2nd order LP (no Zobel on this one - craig will like that, 13k breakup is still down -40dB):
    1.0mH low DCR series coil (iron-core), 16uF shunt cap. That's it. Runs near 84dB w/almost full BSC (+5dB).
    I think you may find the real break up harder to deal with. Joys of testing real drivers vs the published advertising. Great driver especially for the price, but does need care.

    Leave a comment:


  • Cash51
    replied
    Originally posted by Chris Roemer View Post
    0.15cf box w/a 1.5"id by 8"long port will do 60Hz. Will take 20w to 50Hz, which is 100dB.

    3rd order HP w/"L-pad" attenuation: 8uF series cap, 0.15mH shunt coil (to grnd - #20 good here), 25uF series cap (npe), "L" = 2n(ohms) for SR(series resistor) / and 4n for PR. (normal polarity is "indicated"). Fc near 3k (tweeter Fs is 1.5)

    2nd order LP (no Zobel on this one - craig will like that, 13k breakup is still down -40dB):
    1.0mH low DCR series coil (iron-core), 16uF shunt cap. That's it. Runs near 84dB w/almost full BSC (+5dB).
    Thank you sir! Much appreciated!

    Leave a comment:


  • Kornbread
    replied
    Cash51 I am nowhere as advanced in simulation/design as many of the peeps on here, so I really need the .zma and .frd files post all processing, or as measured in box, for crossover work. I use raw driver files, like that which PE generally supplies with their products, to get a feel for compatibility of drivers. If they feel like they will play well together, sim things up knowing some adjustment will eventually be required, then proceed to building the box(or no box) /measuring/constructing/voicing a final crossover.
    They are several on this board that can sim the project, and from concept to finished product, remain spot on target. Not I.
    Yes, as evidenced, Chris Roemer. Although I may not agree with everything he says , he's generally quick to offer sound advice/design assistance which often requires time/effort/knowledge many of us lack.

    Leave a comment:


  • Chris Roemer
    replied
    0.15cf box w/a 1.5"id by 8"long port will do 60Hz. Will take 20w to 50Hz, which is 100dB.

    3rd order HP w/"L-pad" attenuation: 8uF series cap, 0.15mH shunt coil (to grnd - #20 good here), 25uF series cap (npe), "L" = 2n(ohms) for SR(series resistor) / and 4n for PR. (normal polarity is "indicated"). Fc near 3k (tweeter Fs is 1.5)

    2nd order LP (no Zobel on this one - craig will like that, 13k breakup is still down -40dB):
    1.0mH low DCR series coil (iron-core), 16uF shunt cap. That's it. Runs near 84dB w/almost full BSC (+5dB).

    Leave a comment:


  • Cash51
    replied
    I use a 4 ohm amp thus the 4 ohm driver.

    RS125-4 & ND25FA FRD files are attached below. I apologize if this is now the protocol on these boards. In the very distant past, most members had the FRD and ZMA files already, so I likely proceeded under a false assumption. Like the speaker box design concepts you reference, x-over design is also more complex than it may appear. Thanks for your thoughts.

    Kornbread - I recall you and, perhaps, the person you reference is Chris Roemer? Thanks for any help you would be willing to provide.

    Attached Files

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  • tvrgeek
    replied
    Dayton publishes their files. Why 4 Ohm woofer? For small speakers it implies small amps and many do not like 4 Ohm loads.
    You will want to use a Zobel on the RS to help with the cone breakup. Combine that with a LR4 @ 2000 or so. Tweeter looks like it may be able to get away down to 1800 which helps even more with the RS breakup. Nice combination.

    Download their files, download PSD Lite, WinISD Pro and get to work. To do it correctly, you need to decide on the box and baffle as BSC and room gain is part of the crossover design. Designing a speaker is not slapping a driver in a box and expecting some universal crossover will work. A C4 box might work but you should use a HP filter in the amp as there will be a lot of music below the tuning freq. If on an AVR, it will do that for you. I prefer sealed boxes with LR transform circuits to extend the bass for that reason.

    I have used their 125's and 150's. Very clean little jobs, but the measured electrical on my newest set is way off.

    Leave a comment:


  • Kornbread
    replied
    Wish I could help but w/out .frd and .zma files, I'm petty much useless. Chris will probably chime in later, and with a bit more information, get you headed in the right direction.

    Leave a comment:


  • Cash51
    started a topic X-Over Design Help

    X-Over Design Help

    Asking if anyone can provide an x-over design using the Dayton RS125-4 and ND25FA-4...this will be a little 2-way for a small bedroom. Thank you in advance!
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