Dave's 8" woofer + 104mm tweeter speaker build

[DaveFred]

This weekends update,

Put some Osmo Oil finish on the Seawaves, installed the binding posts and the drivers, made measurements in 10º increments 0º to 180º horizontally and -180º to +180º vertically, designed a crossover and did some validation measurements to ensure the design and reality matched.

Today's post will have lots of boring graphs, if anyone wants more detail about a specific slide, please ask.

 

[DaveFred]

And some polars...

 

[hifijim]

Pretty slick... Performance looks good, and the translam cabinet looks very nice.

 

[DcibeL]

And some polars...

Very nice data set, but please uncheck normalization for polar map.

 

[DaveFred]

@DcibeL

Better?

 

[motokok]

Hi, how/what is the laser done (for) when measuring?

 

[DaveFred]

@motokok

Because each driver is measured directly on axis, I use the laser to make sure the mic and driver are aligned

 

[ernperkins]

Wish I was going to InDIYana to hear these.

 

[motokok]

I didn't know that tools exist to project the beam over such a wide area. Can you link the one you use?

 

[DaveFred]

@motokok

It is an older Dewalt DW087, but honestly, any of the contruction/cross line lasers from Dewalt or Bosch will work for this. I am normally using it for hanging kitchen cabinets.

 

[DaveFred]

Small update for today, playing around with PR weight options.

Low end measurements with 0, 20 and 40 grams added to the Dayton DSA270-PR 10" passive radiator.

As my previous graphs show, I was having a little problem merging the passive radiator with the woofer and ended up with a peak at the low end.

Scott Hinson reminded me about the REW option to use "In the Box" microphone measurements and that is how these measurements were done, no merge required to see where the roll off is.

In the end I oped for no added weight and went with the green response.

 

[DcibeL]

Scott gets all the credit eh Dave? No big deal, I don't do it for the fame 😉

 

[DaveFred]

With the PR weights all decided on, it was time to build the XO's, install them, wire up the drivers, button everything up and hope they met my expectations!

I am very pleased with how they turned out and sound!

 

[tktran303]

What was the problem or challenge? Measurement or Merging tool in VituixCAD2 or passive radiator simulation?
I’ve found that the BR and sealed simulations are close to perfect in VituixCAD2 but the PR needs empirical testing; significant mismatch between the model and the result.

 

[johnny5jz]

Great job!! Those look absolutely fantastic!!

 

[DcibeL]

What was the problem or challenge? Measurement or Merging tool in VituixCAD2 or passive radiator simulation?
I’ve found that the BR and sealed simulations are close to perfect in VituixCAD2 but the PR needs empirical testing; significant mismatch between the model and the result.

I suppose the inconsistency is likely PR spec vs reality, where a port is just a tube.

 

[hifijim]

I liked the way your speaker sounded Dave. The low bass, mid bass and upper bass was excellent. The treble balance was just a bit brighter than I prefer, but I liked the sound a lot. The build quality was impressive, it looked great. Thanks for sharing your work. !

 

[wolf_teeth]

I liked them as well, but they were not as bright as some other theme entries.

 

[tktran303]

Interesting comment about the brightness.

@Wolf are you saying that you didn’t feel ot was bright at all; or just a tiny bit on the bright side, but that others were far brighter?

Any ideas where this is coming from? Listener preference, room or recordings?

CTA2034A looks very good.
I wonder whether it’s the the LW slope- speaks to be completely flat or even ever so slight rising
What’s the target PIR or PR slope?

A simple resister on the tweeter (or a DSP shelf filter) to allow for a 1dB drop in the LW will probably suit many listeners/rooms.

 

[hifijim]

I liked them as well, but they were not as bright as some other theme entries.

True. I was a bit disappointed that Dave's project did not make it into the final round... They really sounded good.