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.

 

True! (But my personal subjective preference is that I would not sacrifice non-fatiguing enjoyment and emotional connection for hyper-detail and forensic resolution.)

Is the emotional connection more related to a relax and non-fatiguing sound or to a vivid, lively and high resolution rendering? The jury is still out!

 

This is an interesting subject. Personally I have found chasing the detail has it's downsides. And the level of 'treble emphasis' is very personal and subjective. This IMO has clashed head on with digital sources. I may get shouted at here, but turntables going back 30 years along with probably fairly basic (affordable) phono stages in a combo amp had to my ears less high end extension, which in effect acted as a high filter. So we were served up a coloured and extension limited sound (huge simplification but as an example).

Back to present day, in a great high end system, IMO it is possible to get that upper end detail without fatigue, but many don't get there. I would say 30% at a typical hifi show have me heading for the door on that exact subject.

 

So I am finally very close to my ideal balance of sound. What I have struggled with is the in-room response between the 4 x bass drivers and the Coax that handles the mids and treble range. I have completed all the crossover parts upgrades and adjustments so this last stage is the icing on the cake.

I was really wanting to get a bit more mid and treble gain. The bass is a bit too good. After adding the big Solen Air-Core, the bass has increased in both detail, speed and gain, odd as the Solen has slightly more resistance, but must have zero saturation and more energy transfer? It is not much gain, but is there and affecting the overall FR.

Then I remembered, way back when I configured the room layout, I played a lot with distance from the back wall and TOE IN. I found tiny adjustments of toe in affected the bass energy a LOT. So last night I tried some different angles, very subtle, until I found my ideal in room response. BINGO, I think I have got it. No toe in = less bass, more toe in = more bass, to the point you can cut the bass gain by around 30%!!

The fact the PAPs are open backed means the amount of rear firing energy and how much of that comes back to the front is directly affected by toe in.

With my latest adjustments, I have got the Coax driver come come through more, but not lost any bass extension or drive, rather attenuated the volume of the bass. Manically playing many test tracks I found it is now superbly balanced and detailed right across the full FR. I am at about 10° toe in.

No doubt I will try tiny adjustments to toe in going forward, but right now it is a superb result, and has resolved my in room issue.

Damb, these speakers are so good, I would HIGHLY recommend anyone to take the PAP route, open backed is where it's at IMO. And on a budget. Remarkable product.






Note I am using 2 x JL-Audio 10 inch subs. They are configured at a 45hz slope. I find setting them to almost dissappear works really well. They keep up nicely with the 15 inch Eminence drivers, which I calculate tail off from around 40hz. Care with phase and delay settings gets them dailed in nicely.

The Pass 60.8s go really well with the PAPs. I note PAP use them a lot at shows which says something. They need an hour to come on song, but don't get very hot. I love them. I am running the DAVE DAC direct at the moment, and don't feel I'm loosing much if anything. The interconnects are only 1M to the amps.