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Cheap Speaker Upgrade/Mods: Yamaha NS-A836

Here is the midrange driver. I made careful notes of the polarity on each driver. The connectors on each driver are different to avoid assembly mistakes. However, the polarity of the wires going to the tweeter and mid are reversed from the woofer in its original state due to the phase shift of the two 'crossover network' capacitors. I don't want to laugh too hard at the two capacitor crossover in these speakers, because I just got done fixing up a pair of JBL 3411B and made a big to-do about keeping the stock two-capacitor crossover, but that is a totally case with its weighted woofer cone and tuned port.
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Ok, lets start fixing it up. Or at least changing it in some way that may sound better to me.
Here is the new interconnect plate compared to the existing plastic one. The new one fits right in the hole. It also came with a gasket and some screw holes to make a tight seal. It needed to be pounded in, so its not coming out, but I put the screws in there too.
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I lined the joints from the inside with some extra caulk I had lying around. The easy to see joints were pretty tight from the start but the joint on the front panel had a 1mm gap. Of course Murphy's Law predicted that it is almost impossible to see that to get a good caulk seal. I used a little mirror to do it.
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Tapping the front panel revealed a high pitched resonance in the center of the three drivers. I cut this dowel to fit in there. I do some violin repair and I can't help but make the analogy to the violin sound post. However, in this case, I'm gluing the post in place.
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The 3M sound deadening material is kind of expensive. I ordered 3 sheets and it doubled the value of these speakers right there :)
This stuff has pretty good adhesive on one side, so that may be one reason it cost so much. Of course the idea here is the simulate a good 3/4" thick cabinet from the existing 1/2" wood.
Each sheet is perforated and I split them. I put 1/2 on each side and then split the third section for the back. I did not have any left over for the top panel of the cabinet, however. The bottom is already dampened assuming you have it sitting down WITHOUT any extra feet. If I wanted to put some pointy feet on it I'd want to dampen the bottom. Having mentioned that, I have the crossover on the bottom and that adds some mass there.
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If you really wanna go farther, get some more MDF and double up on the front, rear, sides, top and bottom of the enclosure. Basically enclosing the cabinet with another cabinet. Nah, ignore that. The extra bracing and 3M Sound Deadening material should take care of that.

But if it doesn't... :scratch2:
 
So here is the somewhat controversial 'plug-and-play,' 'one-size-fits-all' crossover network. By the time I can even boot my computer with software to even start to calculate Q, I'm going to be up and listening to these babies :) :)

Wire is 14G (as if it really matters, but this is a 'cost is no object' project, so I paid the extra 3 cents for the bigger wire :) ).
I did solder each connector rather than crimping, but I like soldering (really! otherwise I would not enjoy doing this stuff).

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In that previous post the "Caulk" looks funny. It is because I was using up old 'white' glue I had laying around and you can see it is partially dried. You know if you don't use that stuff it hardens in the bottle after ten years or so...:)
 
ic-racer said:
In that previous post the "Caulk" looks funny. It is because I was using up old 'white' glue I had laying around and you can see it is partially dried. You know if you don't use that stuff it hardens in the bottle after ten years or so...:)
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I was going to suggest glue instead of caulk because it makes the joints more solid, but man, buy some new glue every coupla' years of so :D
 
RickeyM said:
I was going to suggest glue instead of caulk because it makes the joints more solid, but man, buy some new glue every coupla' years of so :D
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I caulked the front panel because the glue would have run and made a real mess, including getting on my hair as I stuck my head in there :). Otherwise I agree that the glue can soak in the seam better.
 
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