Dayton RS 7"/ Vifa XT25 tweeter Crossover


2008-02-01 2:43 pm
Hey all,

I am just wondering if anyone has by chance implemented this driver configuration in a DIY project, and if so what crossover was used? Considering i am currently using an apple laptop, the majority of crossover/speaker design programs are not compatible, so my ability to effectively design the ideal crossover has been nearly impossible. I am currently using a basic 2nd order LR 2k crossover with mixed results.
Loudspeaker details:
Dayton RS 4ohm 7" woofer
Vifa XT25 4ohm duel concentric dome tweeter
The woofer is enclosed in a ~16,000cm^3 vented enclosure with a 6" long 2" wide port.
I realize that my 2nd order 2k crossover is far from idea for the tweeter, so shifting the crossover point up is not an issue.
If anyone has any insight as to possible beneficial modifications i can make to my current crossover or a completely new improved crossover design, any suggestions are more than welcome. Thank you for your time and input, cheers, LukeDuke
Not related to your design question - (and I'm not an apple person) but depending on your version of the apple OS and h/w spec - can you run parallels or something similar and run up WinXP. Then you could run something like Speaker Workshop.

The other option is download at SourceForge and port/compile - depending on your 'puter capabilities.


Can you post your crossover schematic so we can take a look?

The RS series (infact all metal drivers I've seen) have a breakup mode higher up. This results in higher odd order distortion products down in the frequency spectrum. This means most designers I've seen using metal cone drivers, tend to put the crossover point low - ie. before where 1st, 3rd or 5th order products are within -40dB from the reference level of the fundamental. Check out Zaph's website for hsi published designs and any driver measurements he's posted with harmonic distortion and you'll get the picture.

This means crossing over the 7" dayton as low as you can before tweeter distortion becomes worse than the woofer distortion you are trying to attenuate.

The XT25 is a nice tweeter to get an LR2 target acoustic slope from due to its shallow and controlled low end rolloff. However, you can't cross it too low if you are going 2nd order acoustic as too much power will be fed to it.

You should be able to make these drivers work - but you might be looking at 4th order on the RS 7" with 4th (or asymetric) order on the XT25 as Dag suggested.

I think 3KHz however is too high for the Dayton 7" RS. Harmonic distortion aside, you might find directivity a problem and some uneveness in the power (off-axis) response due to beaming.