TM design with FR125S + ND16FA

[Matthew P.]

Hi there,

I'm sure there's tons of designs out there with the FR125S with a tweeter helping the top end, but I wanted to share a design that I just finished that is really inexpensive and easy, but to my ears sounds fantastic. I used a Dayton ND16FA based on Zaph's tests and comments and considering I only really wanted something from around 5Khz up. I tried a couple of different arrangements with it, modeling in Speaker Workshop using others measurements based on similar cabinet size. I just don't have the test equipment yet to do my own measurements. I ended up using a 2nd order crossover on the tweeter and a 1st order on the FR125S the XO ended up being 5K. My intention was to help the raggedy top end while improving the beaming and soundstage. I think this implementation really opened up the FR and made me rediscover some music. It has a similar tonal balance to the FR, but is much more detailed, dynamic, and quite smooth. To be honest, I'm really quite stunned at how enjoyable these are now.

here's the XO:

ND16FA hi pass:

R1 - 2 Ohms
C1 - 1.5 uF
L1 - 250 uH

FR125S low pass:

L2 - 350 uH

Lets see if the attach file works for the modeled frequency response.

So if anybody has the time or ability to throw this together in order to do real measurements, that would be excellent. Otherwise, I've received so much help reading through these forums, that this is one small way of giving something back.

Thanks again and I hope someone can get some use out of this!
Best Regards,
Matt

[Matthew P.]

Just an update in terms of how the speakers are mounted and cabinet size.

I have it mounted in a small approximately 10L ported cabinet: 7.5 x 10.5 x 11.5 (w x d x h). The FR is center mounted an inch from the top and the tweeter is mounted directly in the corner, 1/8" from the FR. I think the tweeter mounted like this eliminates much baffle diffraction and helps create a very impressive image actually. I feel it adds a strong level of realism to the presentation. This arrangement keeps the benefits of the FR in terms of tonality and smoothness, but helps with dispersion, detail and soundstage. Quite enjoyable.

Thanks!
Matt