using V Cap Odam To Improve SQ In mid band of speaker XO

Erik,

Thank you for reply

Original stock value of removed electrolyte cap Is measured about 89 uF

Replacement film cap Is at 86 uF

I would like to add a high quality cap, but I am curious about value - does 0.1 uF Audyn True Cap would be enough

OP:

DIYaudio is a great place to ask about speaker design and crossover mods. In general, the % of difference is what you want to be aware of more than absolute values. If your original cap is +- 10% vs. marked, it’s still good but the original designer probably intened to use the marked, not measured cap. Especially true with older caps.

Next, if the cap is shunting to ground (parallel with the driver) , maintaining or compensating for the original ESR may matter. If there’s a large R (> 2 Ohms) in series it is less important than if there is no R or a very small R value (<2 Ohms) on it’s way to ground. In these cases the combined ESR + R are critical values which may be needed to prevent the impedance from collapsing.

Keep this in mind as using parallel caps may have unintended consequences, and the ESR of the entire assembly should be measured and taken into account.

Lastly, if this cap goes to ground the big improvements are going from electrolytic to film, and less so after that.  If you have already made that change getting fancier is a tiny difference if any.

Erik,

Big thanks.

Would you please give me your preference when you have to obtain higher value cap (for example 90 uF)

1) one cap only   2) two caps In parallel of 1/2 value   3) one cap of 85 uF standard quality and one high quality cap at 4.7 uF

Is there a 1 / 100 rule when you add caps of various values

OP:

Something else you should be aware of is that when parallel caps became fashionable (1980s) caps weren't nearly as good as they are today.  Electrolytics in particular had high ESR's and high inductances and were not easily available any better.

I strongly encourage you to experiment on your own here, and in order to experiment you need to have affordable parts.  Try out some affordable Mundorf MKP caps and splurge a little on small Audyn TruCopper as well. Axon makes affordable film caps which can be greatly enhanced with either of the other two.

I like Mundorf MKPs a lot for the price, and physical size, but they sound a little dark.

Best,

Erik