Pure Audio Project upgrades and tweaks

Starting this thread to discuss Pure Audio Project open baffle speakers, upgrades and tweaks. @Kingrex - if you have had both the horns and Coax10, I would be interested in hearing how they compare. And I copied your earlier post below.

What cables upgrades did you use? And can you share a picture of where you located the crossover? Is it attached to something else, or sitting on the floor? I was wondering about the height of the midrange/tweeter and if I should rake the front up. My system will be the Trio15 Coax10, Playback Designs MPS-8 source and Pass Int-25 amp. I'm still waiting for my walnut baffles to ship from RJ Millworkers.

You have to get the updated speaker cables. Its critical.

And , you have to separate the crossover from the frame. Again critical.

If the crossover is touching the frame, the music is very smeared from the intense physical vibration.

If you use stock, instead of upgraded cables, you loose life, air and bass. Less coherent.

The speaker is very good with these tweeks. You don't need to futz with any caps or reaistors with the Coax crossover.

You need to be patient. They take 500 hours like any speaker to break in. 2000 or a year to really be there. I actually put my coax in the basement connected to a class D amp and laptop for week and let it rip sitting on the floor. I would go dowm 3 or 4 times a day to switxh the album and volume.

Also, mine sit on a 9 inch tall very heavy block of wood that sits on fiberglass insulation. A rug would also work. Massive improvement in bass. Just shocking. And, it raises the center of the coax much closer to ear height. Otherwise its too low and like sitting in a balcony.

The fabric over the top keeps the sun from striking the driver. That is all its for.

 

The coax compression is the tweeter????.
I also found putting the speakers on a dense 9" tall block helps the bass a lot. And it lifts the tweeter/coax more to ear level.

Did you get better cables from ceossover to drivers. Also, that crossover can't touch the frame. Its a disaster when it does. A horrible smear from the vibration.

 

Yes the compression driver in the Coax (Baymer).

I have 2 bass drivers below the coax, so the height is just right.

I am looking at copper ribbon cables. I have asked for a price from Verrastar.

I have the crossover on top of a thick granite sheet, on top of the speaker base. It is good, little vibration. I also glued many of the caps and resistors in place as you find in many subs. I can't have the crossovers outside the frames as no room left.

 

So I added a Jupiter Copper in oil 2.2uF cap on the comp driver / HF circuit. First 2 days, oh dear it's sound dull and flat. Next 2 days it is opening up and the magic is happening. Lots more burn in, but we got over the panic stage.

This as I suspected this is a very nice tweak. I am very sensitive to treble grain, especially in digital. The Jupiter cap has the same detail and resolution of the Mundorf gold/silver cap, but is much more organic and realistic. Female vocals for examples are way better. At 240 euros for 2 caps not cheap, but the whole speaker has got an upgrade.



The Jupiter cap is the red/brown cap mounted vertically. It is also bypassed with a silver Duelund 0.01uF mounted under the board. I also bypassed the other 3 Mundorf caps with tiny 0.01uF Mundorf Gold/Silvers.

So I think the crossover is done, maxed out and I am very happy with the sound. In December I will look at changing the speaker wiring. It is Van-den-Hull as supplied. I am looking at buying silver/copper bare wires, and making my own loom up. I considered Verrastar foils, but probably can't afford them.

Onward.....

 

I ordered the silver plated copper wires for the hook up cables. I will do the compression driver and mid driver first.

I am going to use 0.4mm, 0.6mm, 0.8mm and 1.0mm wires, probably 3 of each, then shrink wrap the twisted bundles, cotton rope and some cotton bands, then tinned braid over the 2 channels, then pvc braided jacket. I found a video on how to assemble then on YouTube.

I'll report back in a few weeks, once I get all the bits and build them.

 

Change the 6.8mh inductor to air core.

 

Hi Rex. It is a 12.8 inductor. I would but I can't fit an air core as no room left. TBH to bass speed and detail I am getting now with the 3 caps on the inductor, it is superb.

 

Odd. Why would yours be different than mine? Mine is hanging on a wooden peg below the crossover.

What caps go to the Coax. I like the Jupiter copper beeswax.

What do you sense getting from the bypass caps.

 

Odd. Why would yours be different than mine? Mine is hanging on a wooden peg below the crossover.

What caps go to the Coax. I like the Jupiter copper beeswax.

What do you sense getting from the bypass caps.

Legolas has the Quintet Rex… the Trio runs with a lower inductance because of the different setup with the impedance of the extra woofers running in the quintet.

I find the Trio and the Quintet display quite different characteristics and strengths that come out in the varying ways they respond to different music… I like both.

 

Owe. I missed that. Makes sense.

I'm still thinking of biamping. I would start by using an active crossover. I would have my preamp signal go into the active crossover. On the high side, I will pass full frequency through the active and into the high side of my stock crossover. The coax will continue to be shaped by this.
On the woofer side I will try and blend to the high side and run the bass amp from the active filters.

I am thinking of doing this to limit what my preamp sees as loads. It may all fail. Who knows till you try.