Kairos

[richidoo]

Sho'nuff, Bill! Thanks 

[rollo]

   Rich could there be an inductance issue with the bass caused by the crossover as well ?


charles

[jimbones]

Rich, from my experience, or at least what my mentors have shared with me is that the ringing usually occurs with higher value coils. What XO frequency and coil value are you using?

[richidoo]

   Rich could there be an inductance issue with the bass caused by the crossover as well ?

Inductance is a necessary evil, it's the only way we know how to  make speaker level crossovers. Inductor coil in the woofer filter makes the low pass filter work, but there is a cost, although I chose the best coils I could find to minimize that issues. The resonance was probably a combination of 2 coils (filter and VC) plus the cap. The resistor seems to have really helped a lot by damping the filter coil. I'm pretty happy with how it sounds now, but you know how it goes a month from now start hearing another problem.     Compared to the active amp experiment, even the best coil has its issues.  The driver's voice coil has induction, which serves to roll off the high frequencies. This canbe used to advantage and some 70s era drivers were designed with higher inductance so they wouldn't need a low pass filter at all.  These days, VC inductance is naughty and they try to reduce it to let the crossover filter do all the work.  My woofer, the SB Acoustics Satori has very low inductance, it's impedance curve is dead flat out to 10kOhms. So it sounds like a full range driver with rising FR. A little contour network to flatten it out and it would sound pretty good! No resonance breakup to speak of. It is a papyrus fiber cone, or something weird like that. 

Rich, from my experience, or at least what my mentors have shared with me is that the ringing usually occurs with higher value coils. What XO frequency and coil value are you using?

Thanks Jim. You are right, it IS a relatively large value coil, which is used to create full 6dB of baffle step correction, necessary to make this little woofer sound bigger than it is. I can't disclose the actual part value in public because it is IP of Meniscus. The crossover frequency is 1900Hz.
Rich

[mresseguie]

Hello, all.

Rich,

Thank you for this thread. It's whetted my appetite to finish my Adelphos project sooner rather than later. I'm psyched to actually hear them. How many hours of break in can I look forward to--100 hours? More? I love how you used the Baltic Birch plywood over MDF or my choice of pre-finished plywood. Man, I wish I owned a table saw. I'm sure my wife would not notice if one suddenly appeared....

I suspect I was on my way to making a couple mistakes with how I'm constructing the cabinets. I definitely need to brace the sides. My largest coil is a tad smaller than yours, but I was planning on running a wood dowel from the bottom of the coil to the top of the cabinet as a vertical brace. Now I understand I can do it without creating a problem. Boy, have I got a lot to learn about speakers!

I think I need to read all the other DIY speaker threads now.

Michael

[richidoo]

Hi Michael,
100 hours should be enough. My break in was uneventful, didn't notice (or is it don't remember?) much change during break -in. But it will open up, sound more liquid and play lower after break in. The sound may change unpredictably during this time, so don't be surprised if it gets bad for a short while.

Check your crossover wiring before startup, and start with very low volume just to make sure it sounds right before cranking it up. You don't want tweeter trying to play woofer's part.

I do love my table saw. I have ridgid 10" contractor saw, about 12 years old. Dewalt makes a nice portable saw if you need to hide it when not in use. Very handy! But it leads to endless projects.