Face-Swap! Tweeters will get transplant...

[Wolf]

Re: Face-Swap! Tweeters will get transplant...

Indeed, nice look. Though are you sure you want to offset the tweeter? What about all that beautiful symmetry you have going on?

The focus is to have them face forward, and have automatic toe-in.
Otherwise, I see your point.
Later,
Wolf

[Wolf]

Destinations Update...

I got the panels all cut out today. I ended up using 3x 3/4" MDF 2' x 4' boards and a single 1/2" 2' x 4' board. All of this gave me 3 internal braces, and everything else. I have to make the rear panel in 2 pieces, as the material did not allow me to have 2 more full-length boards. No matter, one brace will protrude flush with the rear boards and make it less likely to ring/flex.

I laid out the xover with what I have on hand at the moment, entailing a 10mH SL core, a 2.0mH coil for the shunt, and a 7uF cap for the tweeter zobel; the 3.3 ohm and 4 ohm resistors are en-route currently. they fit on a 7" x 8.5" board, mainly because of the C-coil, but I hope I can use a lesser value and save some space and maybe some cost in the xover. We'll have to see...

I used the broken rear panel from an old console radio that my aunt gave me (not the radio, just the panel) as some reusable peg-board. Bigger holes, and offset as well, may allow me to try out the push-to-expand automotive pins I posted about awhile back for mounting. I'll layout what I have on the boards tonight for a pre-run.

Later,
Wolf

[Wolf]

Re: Destinations Update...

I will be taking the xover and drivers and running a sweep tonight to verify the most recent sim. The C-coils apparently are off-spec, and actually work more to my advantage than the larger value would. I gained about 1.5dB sensitivity, and the plot is a lot smoother. I dropped a 30 ohm across the tweeter to further damp its Fs, and added a resistor on the 25uF (formerly 20uF) cap to damp the woofer's knee a bit more and align the phase again. Reduced resonance peak in woofer a smidge more with reduction to 10 ohms in the LCR.

So- here's the sim...

Later,
Wolf

[Wolf]

Re: Destinations Update...

And here is the measured plot of the most recent impedance out of box. I did not switch the tweeter to the 2.2 ohm value, so that is why the tweeter impedance is a little higher in net value.

The 2-3 ohm change in the impedance at 500 Hz makes me wonder a bit, but it could be the variance in driver-to-driver. Otherwise- it looks quite close to the simulation.

Later,
Wolf

[Wolf]

"Destinations" Progress...

I have the second baffle gluing, and the first is glued with it's rear-spine attached. I had to reinforce the joint, so this happened. The first one came out good and tight, but I'm not sure the second one will be the same. I'll have to wait until tomorrow to know for sure.

Oh- and if you're wanting pictures, you'll have to wait a few weeks...\

Once the baffles are ready, I can cut the rebates and recesses (with a jig), and then start assembling the rest of the cabinets.

This is going to be a bit tedious cutting the holes...:eek:

Wish me luck!
Wolf

[isaeagle4031]

Re: Face-Swap! Tweeters will get transplant...

Can hardly wait for pics Ben. Are you pushing to have these done for MWAF?

[Wolf]

Re: Face-Swap! Tweeters will get transplant...

Can hardly wait for pics Ben. Are you pushing to have these done for MWAF?

Yep! I'm doing a little work everyday on them right now. I hope to route holes Saturday, and then cut dados, rabbets, and biscuits- I have plenty to do yet!

I'm hoping I don't have to voice them much....
We'll see,
Wolf

[isaeagle4031]

Re: Face-Swap! Tweeters will get transplant...

Well I hope to see them there. I'm sure we won't be disappointed. I like the look and built in toe-in thought.

[Wolf]

Re: Face-Swap! Tweeters will get transplant...

Well I hope to see them there. I'm sure we won't be disappointed. I like the look and built in toe-in thought.

Even if I don't get them finished completely, or have the xover refined, I should be able to take them to the event.

Later,
Wolf

[czag]

Re: Face-Swap! Tweeters will get transplant...

Any thoughts on the 9700 tweeter, how is the sound quality?

Chris

[Wolf]

Re: Face-Swap! Tweeters will get transplant...

Any thoughts on the 9700 tweeter, how is the sound quality?

Chris

I'll update the thread when I get the pair up and running. As for now- I can say that the impedance sweeps are super clean without anything standing out, but that's all I have for you currently.

Later,
Wolf

[Wolf]

Re: "Destinations" Progress...

Baffles are virtually complete. I had a couple snags in process, and still have a gap to fill on a tweeter rebate. The trim-router slid down the angled board while it was trimming that edge, and it's a little large currently on one side. Hopefully some epoxy may do the trick.

Once I fix that, and sand the baffles smooth, I'm ready to cut the rabbets and dados and glue them up!

I'm really liking the aesthetics of this project as it goes along...

Later,
Wolf

[Wolf]

Listening currently!!! Nightwish on the fly...

Well- I have them running and have already adjusted a couple things:

-The 20+5.6uF caps on the woofer; I removed the 5.6uF. Being the woofer was off-axis and the tweeter was not, I needed a bit mre midrange fill-in.

-The tweeter was hot to start off with. The initial sim said 3.3 ohms, which I left in even after the revision said 2.2 ohms in simulation. I was gambling on a bit hot tweeter as things normally result. Even then- I bumped it up to 4 ohms cuz it still wasn't enough.

....and to come:

-I think I have to further tilt down the 97000's response, as it's awfully hissy right now at louder volumes. I have a couple things I'll try and simulate to see the net effect, but I feel one of the 3-4 items or a combination will tame it completely.

...a synopsis:

These things can take the juice!!! :D:D I mean, they stomp all over every 8" and other 2-ways I've done as a full-range 20-20k comparison.

The 97000 is a VERY revealing and resolving tweeter. Everything is super-clean and articulate, with delicacies underneath still being clearly portrayed behind the more aggressive instruments and passages. I like it, and it's worth its $175 current price. It jus takes a bit of care to get the balance right on it.

The Airborne FR213B8-10M in this PR alignment is amazing. It digs deep, punchy and solid, and It never has any overhang. I attribute that to the large motor and very low Qts. I killed a lot of its sensitivity using the alignment I gave it in combination with the xover, but it was worth it!! Bass-guitar articulation is really nice too.

More later,
Wolf

[Wolf]

ARGH!! Screws/surround issues.... Ideas??

I know this was discussed prior a couple weeks back, but this has a frame lip, and a surround that protrudes into the mounting holes.

I installed them both with and without nylon washers to try and NOT pull the surround when solidly mounted- To no avail.

I went into the LR after getting up and around today, and the small peaks where it tugged yesterday had further opened up to make an air-leak. I didn't even run them today. I immediately lightened the screw tension, and the adhesive seems to have accepted the surround back to its original position.

Now- what to do about it?

I've tried with and without washers on the screws, and I've tried flush-heads. I even tried a little adhesive to keep the surround position, but that didn't work.

My only other thought is to somehow make a 'face-gasket' for it out of 1/4" hardboard, and use speaker glue to secure it tightly. This way, the screws will clamp the surround in place, and no tugs will happen.

Any other thoughts?

Later,
Wolf

[Paul Carmody]

Re: Face-Swap! Tweeters will get transplant...

Can you get away with "minimum tension" on the screws, or is the driver loose?"