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.

 

Yes I got the biggest Aircore I could find just to get the DCR down to 0.467 ohms. The stock ferrite inductor is 0.39 Ohms. I don't hear a drop I bass volume. It is only 0.08 Ohms difference, so not a problem.

The caps change the mids and table, the inductor the bass, probably to a similar level of improvement TBH.

That’s good to hear, in the quintet horn xover there’s a 10 mH inductor so with the 10 awg and the 8 awg for the Solen air core there’s a similar small gain on dcr over the stock inductor… so looking at an additional .06 ohm over the stock 15 awg Mundorf BS140 feron core.

I’ve hesitated on changing out the inductors earlier because I was considering some other changes first and I was more comfortable when I was changing out the caps and resistors as these were all directly matching spec.

Was thinking/hoping 60 milliohms wasn’t likely going to create any issue… but it’s nice when someone else goes first tho. Really happy it’s working out for you.

I found really nice gains overall with the Mundorf Supreme Evo oil cap upgrade that I did earlier and almost as much with Path resistors so if the inductors are a similar level of return that’d be great.

 

That’s good to hear, in the quintet horn xover there’s a 10 mH inductor so with the 10 awg and the 8 awg for the Solen air core there’s a similar small gain on dcr over the stock inductor… so looking at an additional .06 ohm over the stock 15 awg Mundorf BS140 feron core.

I’ve hesitated on changing out the inductors earlier because I was considering some other changes first and I was more comfortable when I was changing out the caps and resistors as these were all directly matching spec.

Was thinking/hoping 60 milliohms wasn’t likely going to create any issue… but it’s nice when someone else goes first tho. Really happy it’s working out for you.

I found really nice gains overall with the Mundorf Supreme Evo oil cap upgrade that I did earlier and almost as much with Path resistors so if the inductors are a similar level of return that’d be great.

IMO the 0.06 Ohms you will not notice it. I would go for the solid core 10 AWG 10mH version.

Don't forget to change the 82uF cap attached to the bass at the same time, that also affects things as much as the inductor.

I am not an engineer, but I imagine the reason you have 10mH v my 12mH is my Coax has a 10 inch driver open to the bass end, so augments the bass a bit more than your Horn1, which tails off rapidly around 1.5Khz I would suggest.

If I had the horn I would look at the next CD up in the Bayz range, I think there is one with a bigger coil but the same 1inch throat. I upscaled my Zingali horns with the next size up B&C CD and it had more dynamic range and more relaxed / smooth treble.

 

IMO the 0.06 Ohms you will not notice it. I would go for the solid core 10 AWG 10mH version.

Don't forget to change the 82uF cap attached to the bass at the same time, that also affects things as much as the inductor.

I am not an engineer, but I imagine the reason you have 10mH v my 12mH is my Coax has a 10 inch driver open to the bass end, so augments the bass a bit more than your Horn1, which tails off rapidly around 1.5Khz I would suggest.

If I had the horn I would look at the next CD up in the Bayz range, I think there is one with a bigger coil but the same 1inch throat. I upscaled my Zingali horns with the next size up B&C CD and it had more dynamic range and more relaxed / smooth treble.

Figure a 8 awg air core would be a monster! I am leaning towards the 10 awg as you have gone… it will be interesting to see if the bass characteristics develop further during burn in.

In the quintet horn there’s a two way first order with just one cap, one inductor and two resistors. With the 10 mH Mundorf inductor (and also working on it running with a 33 uF cap) I’d figured it’s crossing the woofers to the horn somewhere around 600hz. In typical audiophile overthink I also had been considering swapping out to a 450hz horn that Troy Crowe developed. I figure I need to pin that choice down first as well.

 

Figure a 8 awg air core would be a monster! I am leaning towards the 10 awg as you have gone… it will be interesting to see if the bass characteristics develop further during burn in.

In the quintet horn there’s a two way first order with just one cap, one inductor and two resistors. With the 10 mH Mundorf inductor (and also working on it running with a 33 uF cap) I’d figured it’s crossing the woofers to the horn somewhere around 600hz. In typical audiophile overthink I also had been considering swapping out to a 450hz horn that Troy Crowe developed. I figure I need to pin that choice down first as well.

Interesting. I would definitely upgrade the 33 uF cap. On the horn, you could go full round flair and bigger in size. In this case it would mean a new centre frame section (taller).



I did a rough visual way back when I was considering the horn1.