High pass filter capacitors

Why are you doing this?
 

I have GR Research NX Studios. (Bookshelf)

They can’t handle below 70 hz. 

gdaddy1

Thanks for the video. I haven’t seen that one. 
I’m hoping this is not the case here. 
Danny Richie designed these speakers and suggests to do this if playing at louder levels. 
I have them with an AV processor with its internal crossover cutting the lows to the bookshelf speakers. They sound amazing to me. Very deep and wide sound stage. 
My plans are to upgrade to a BHK pre used in bypass for the AV system. 
This will require a filter on the pre output. 
Any suggestions welcome. 
I will check out the Miflex caps   Thank you. 

I’ve look at the vcaps. I’d need 4 on XLR lines. 😫$$

In this range of capacitors, there are a number of excellent brands of caps for far less than $300.

Audyn TruCopper, and even some excellent Duelund models like this one.

I strongly recommend you practice however using like $2 poly caps first, just to make sure you have the right values and wiring.

Also, I think Parts Express has some modular XLR adapters.  They are like M to F adapters but you can shove little parts inside. Perfect for this type of prototyping.

     It's been decades, but- when I needed high quality, small value caps, for doing exactly what you are (using a Placette and/or Dahlquist DQ-LP1): Michael Percy was my go-to, for the best parts available.

                    He also offered a wealth of valuable information.

                            Can't even swear if he's still in business.

                                                     BUT:

                            https://www.percyaudio.com/Catalog.pdf

                                              Happy listening!