Dayton CX150-8 Coaxial Project

[jhollander]

Bill skip the NF on the port (for me) it just means more math.

[JavadS]

Constrained layer damping experiment:

Bill great progress, It’s been a while since I checked in here! FWIW i’d call this mass loading not CLD, still should be effective at lowering the resonant freq and amplitude of those panels *tup* Javad

[Chris Roemer]

If the Z-dip bothers you, I've noticed more than once (on a bandpass) that running the series components 1st (closest to amp) followed by the shunts, (for some reason - unknown to me as yet) the Z-min holds up higher. Not sure all softwares can handle that topo., but some of them can.

[ernperkins]

Bill skip the NF on the port (for me) it just means more math.

John, I hereby strip you of your title "engineer".

[4thtry]

Bill skip the NF on the port (for me) it just means more math.

John, here is your math assignment. I made the NF woofer cone and port measurements 3 days ago, so both are attached. I made the NF midrange measurement last night. Even though these measurements were made at different times, all of them use the same amplifier volume control setting of 32dB.

Note: My KLH KL-2400 Stereo Receiver Amplifier has a digital volume control with detents that adjust the volume in 1 dB increments from 00 to 63dB. This works nice when making measurements because if I note the "on screen" dB level, I can always come back later and set this exact level to make additional measurements.

Bill

NF woofer cone.frd
NF woofer port.frd
NF midrange cone.frd

[wogg]

This is excellent detail, thanks for keeping up on the documentation of this project!

[4thtry]

Bill great progress, It’s been a while since I checked in here! FWIW i’d call this mass loading not CLD, still should be effective at lowering the resonant freq and amplitude of those panels *tup* Javad

Thanks, Javad. I set the speakers side by side. One is fully damped with my steel bar mass loading technique while the other has no damping at all (see pic). I can do a very quick back & forth A/B knuckle rap comparison. Just as you said, it is very effective at lowering both the resonant freq and amplitude of the rap. Bill

[4thtry]

This is excellent detail, thanks for keeping up on the documentation of this project!

You are welcome! I had not posted for a while, so I had quite a backlog of detail to report. I have until 11/15 to get my crossover parts order in to PE, as this is the deadline on my "Pile-on-the-gear" coupon. Will post a few detailed pics of the finished xover and the charge coupling circuit wiring for the tweeter series capacitors. Bill

[4thtry]

If the Z-dip bothers you, I've noticed more than once (on a bandpass) that running the series components 1st (closest to amp) followed by the shunts, (for some reason - unknown to me as yet) the Z-min holds up higher. Not sure all softwares can handle that topo., but some of them can.

Thanks for the tip, Chris. I think XSim can handle almost any topology. Will try this out and report back my results.

Bill

[jhollander]

John, I hereby strip you of your title "engineer".

I guess this means I'm just a manager with poor spelling.

John, here is your math assignment. I made the NF woofer cone and port measurements 3 days ago, so both are attached. I made the NF midrange measurement last night. Even though these measurements were made at different times, all of them use the same amplifier volume control setting of 32dB.

There's no worries on the nearfield levels as the Blender will help get the match right after adding the baffle to the nearfield. Let me know if you want the manipulated FRDs back.

[4thtry]

... Let me know if you want the manipulated FRDs back.

Yes, that would be great. I would very much like to see what you come up with.

[jhollander]

Bill did you gate any of the 1 meter readings?

[4thtry]

Bill did you gate any of the 1 meter readings?

They were all sine sweep, blended, 5ms gate, 1/48th octave smoothing.

[jhollander]

They were all sine sweep, blended, 5ms gate, 1/48th octave smoothing.

Interesting, as I'm not getting a good, T + M and T+ W match in pcd and xsim.

[4thtry]

Interesting, as I'm not getting a good, T + M and T+ W match in pcd and xsim.

Here are my "get file" matches. In XSim, I used a -0.88 (in) mod delay on the tweeter and a +10.18 (in) mod delay on the woofer for all simulations. The matches look about as good as I have gotten on other projects. Maybe my 5ms gate was a little too long, given that my mic was only 37.6 inches off the floor. Reflective surfaces in other directions were about 5 to 6 feet away. What do your matches look like?