Neo8/Neo3/RS225 Progress...Suggestions?

[LouC]

I did another set of measurements on my 3way. Got some nasty peak & trough phenomena that I couldn't clean up. They may be baffle related or something else. If any of you open baffle guru's have suggestions (other than mine on the page) I'd welcome them.

Neo3/8/225 Progress Page 2

[Jed K.]

Lou, are the drivers offset at all? I'm assuming you first modeled the driver layout though.

Jed

[cjb]

Just for fun I might try inverting the bass bin to see what that does to the response.

[biff]

Have you tried modeling the neos on a circular or oval baffle to diffuse the baffle diffraction signature? I would imagine a rectilinear source with parallel edges would have the same effect as a round baffle with a centered regular driver, i.e. worst case.

[jonasz]

What about placing the Neo8 horizontally? Should be less front/back cancellations and maybe result in a smoother response?

I'm watching this project with great interest!

[dlneubec]

Hi Lou,

Your trapezoid idea seems like a good one to try. I would also look at the baffle width on the open baffle section. IIRC, John K. recommends about 2x the driver width for an open baffle flat panel (no wings) and you are certainly much wider than that. I'm not sure how this rule of thumb applies to a ribbon, however. You might PM John for his thoughts.

Just plugging some numbers into John's ABCDipole, assuming you would want the width of the driver in the model to be about the same as the Neo8 width, (I assumed about 8cm or so), it suggests a maximum baffle width of only 6.25". If I plug 6.25" into the baffle width, as compared to your 10.5", I get a considerably flatter simulated FR (see below). However, ABCDipole is based upon circular drivers. It calculates the driver diameter figure from the SD you enter. I don't know if it is valid to enter a smaller SD in order to get the driver width to simulate the 3" width of the Neo8, which is what I did for this comparison.

If you don't own ABCDipole, you might mess with the open baffle option in the EDGE, to see if a narrower baffle might help.

Here is what I get with these assumptions and a 10.5" width baffle:


Here is what I get with a 6.25" baffle width:

[LouC]

I'm going to try a couple more baffle shapes & a deeper chamber and remeasure.
Right now I'm involved with a consignment 3 way, so I'll have to try to work both...

I'll keep you all posted.

[tomdaugherty]

Lou, any progress on this set up? Curious minds want to know.

[jonasz]

http://www.lonesaguaro.com/speakers/...eo8Neo3P3.html

[tomdaugherty]

If using two 225's wouldi it change the xo quit a bit?

[cjd]

If using two 225's wouldi it change the xo quit a bit?

Yes.

[LouC]

These will sit for a bit. I will redesign the top of the box with a closed chamber in mind. Meanwhile, I have a couple of consignments & "real" work to do. Page 3 sums up the progress.

I probably need another Neo8 -- not another RS225! Plenty of bass.
I actually got to a palatable OB design --I just didn't like it as well as the chambered setup.

[jonasz]

Lou, did you ever try the Neo8 horisontally? (in dipole that is)

[LouC]

Lou, did you ever try the Neo8 horisontally? (in dipole that is)

No, I have not. When the Neo8 is vertical, there is very limited vertical dispersion, so it had not occurred to me to do that. Maybe someone will that a try.

[jonasz]

Well, my gut feeling say it would generate less dipolecancellation due to the directivity and therefore result in a more even response? I believe Martin Logan used it like this in their Mosaic speaker.