Anarchists Build Log

[4thtry]

Nice fix. The problem area appears to be completely gone.

[tomzarbo]

Looking good! This makes me wonder why I hardly ever use oak, it looks pretty nice.

[PWR RYD]

They look great!

[wogg]

Actually not a huge deal. After sanding down with 220 grit the look is even and quite cool in a kind of vintage weathered way.



Not enough red left though, so another hit of RIT.



After drying and rubbing down these may be ready to seal. I'll check them out tomorrow and see how I feel about the color.

[PWR RYD]

Sorry wogg for continuing the off topic. And sorry for your finishing woes. I'm sure they'll sound and look great when you're done.

[PWR RYD]

I've never considered any measurement further than 60 degs off axis worth taking or worrying about. Thanks Bill for confirming that.

[wogg]

Interesting analysis Bill! I hadn't really considered how the lack of 360 degree data would effect the power response target. I have a stack of parts with some adjacent values to play with when I get to the real life prototyping phase. For now I've pivoted to finish.

Here's the right side baffle, at this point I was ready to do one more layer of red dye to get it deeper before doing the poly seal.



Pro tip: glue residue on boards is invisible until you start staining, use a solvent on the bare boards first! I hear lacquer thinner will show you where the glue is, as will a black light for some types of glue.

I think there may have been a piece of tape on this board at some point, the lack of penetration is in a slightly rectangular area. This was not visible at all until the ebony stain was applied.



There's not a lot of good methods to fix this after the fact, blending will be difficult. On some cabinet maker forums someone mentioned using sandpaper dipped in the stain to work it out, adding stain while sanding through the glue residue. So in an effort to avoid sanding the whole baffle down for a complete re-do, I gave it a shot.



I gave it a couple applications, let it soak a good while...



Well crap, that made it worse.

Now I'm back to sanding this baffle down to clear that area and re-apply an even finish. I figure I'll do both baffles so the end result is consistent. Taking a lot more time than planned, but on the upside the last time I did this add finish / remove finish / refinish and repeat business it resulted in a depth that was pretty cool.

[4thtry]

I tried to edit my post to correct a typo, but then the spreadsheet disappeared. Here it is again:

[4thtry]

I put together a spreadsheet showing how much the VituixCAD curve slopes change when I flip from partial to full spin data. When setting up your target curves for Listening Window and In-Room Response, this should give you a good idea as to how much you need to compensate. No compensation for the Listening Window target curve and about 0.14dB/oct compensation for the In-Room Response target curve.



Regarding your other questions, I'll give these a try as best I can. Not sure about 9ms gate in ARTA before export, will have to skip that question. Regarding the merger tool in VituixCAD, I do everything without minimum phase. I adjust the delay value manually to align NF phase with the FF phase curve. "With 2 channel data, Z offset is not needed and should be cleared to zero?" In VituixCAD, Z offset is generally zero'd out, but only for flat, non-stepped baffles. The X & Y values are still used for simulation in VituixCAD. The x,y,z values that you have entered above appear correct.

[4thtry]

I noticed that you did a partial (0/30/60/90) instead of the full spinorama due to space limitations. This got me thinking as to how big a difference this would make in the various modeling curves. Which curves would be affected the most and why? So I loaded my Diffractorama speaker model into VituixCAD to generate a comparison. The first graph below shows several VituixCAD curves with my full 0/15/30/45/60/75/90/105/120/135/150/165/180 data set loaded for all drivers. The 2nd graph below shows the same curves, but this time with only the 0/15/30/45/60/75/90 partial spin data set loaded for all drivers.

As you can see, the biggest change is with the slope of the dark blue power response curve. The In-Room Response (orange) slope drops a little bit too, but no where near as much as the power response curve. The Listening Window (green) curves seem to show little change. This makes sense, because there is much less high frequency energy in the 105 to 180 degree data curves. Also, the Directivity Index (red) shifts down significantly while the ERDI total curve (Salmon/orange) seems to show little change.

[a4eaudio]

Double post

[a4eaudio]

I have to admit I wasn't really grasping the RIT dye, stain process. But that looks nice!

[Billet]

Looks great.

[wogg]

I think I have a decent process now. Here's the test board with just about the final look. You can see other stain test patches all over.



It'll be dye, stain, dye, stain... repeat until happy. Then satin poly multiple coats. This does take extensive dry time between cycles, but the results are pretty cool. Bench reset to start the first stain soak on the actual baffles today.

[wogg]

I've been abusing the extra oak board I have from the baffle with a variety of Minwax colors, conditioner, and now RIT dye. I think this one is looking the best, a good soak with RIT followed by a pair of 10 minutes soaks of Minwax ebony, then another RIT soak. This is the powder version of the dye, one full box mixed with about 8 ounces of water. I think I'll try the poly on it after it's fully dry this week and see what it looks like with a satin seal on it.