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

Not enough experience with V Cap Odam In XO ?

How about using Jupiter Copper Instead of V Cap Odam In same condition

OP:

If you mean ADDING it so the total uF = 2.7 + 3 = 5.7uF, then absolutely not.

If you meant replace, then 2.7 is right on the edge of what I'd recommend trying without compensation.  I'd add a .27uF to get close to the original 3. 

An easier and cheaper alternative all around though is adding an Audyn TrueCopper cap in the range of 0.1uF to the existing. 

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

Erik,

Thank you for support.

Would you please explain why there Is a big advantage If we change with quality film cap electrolytic cap that shunts to ground. Doesn't It go all the signal through shunt cap to ground.

OP: Not sure what you are asking, but let me clarify.

Generally speaking, the basic filter components are either in series with a driver, or parallel to it. It’s the later I refer to as shunting to ground because a cap becomes a short at high frequencies. Likewise a coil becomes a short at low frequencies.

A difference of 0.2-0.5 Ohms in series with an 8 Ohm driver is not a big deal, but if the part is parallel with the driver, a difference of this much can be major.

The special case of a Zobel, with a cap going to ground with a larger resistor (>4 Ohms often) is again a situation where the ESR/DCR is less critical.

In post https://forum.audiogon.com/discussions/using-v-cap-odam-to-improve-sq-in-mid-band-of-speaker-xo/post?postid=2763745#2763745 you are saying

" 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. "

I would like to know why there Is big Improvement when you change cap that pass signal to ground.

OP: 

Ahh, well the conventional wisdom is that the caps in series with the drivers matter more than the  caps in parallel, but a couple of users have reported that even with some positive effects from stepping from electroclytic caps to at least a film. 

I strongly encourage you to experiment for yourself with affordable parts. :)

Best,

Erik