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.

 

I was looking at going aircore inductor too, since I made a plinth for the xover and it is external now I was thinking of making a wood platform above the xover and mounting it there and running the wires down to the xover, does anyone have a reason why putting the inductor above the xover may not be a good idea? Seems like if I keep it horizontal it will just radiate out and should not effect anything, but I could not find anyone doing this online so just wanted to make sure before I take the plunge.

 

@Bör B I don't know about the placement and the effect it might have. I do recommend the upgrade. I found it to be a great value for increased performance.

Has anyone tried flipping the polarity of the center driver? I have the Voxativ and I find it sounds much better more detailed with the polarity of the Voxativ flipped. I'm guesing it blends better or I messed up when building the XO from scratch.

I agree with Legolas, upgrading the caps can bring some nice results. Worth trying different resistors too.

 

@Bör B I don't know about the placement and the effect it might have. I do recommend the upgrade. I found it to be a great value for increased performance.

Has anyone tried flipping the polarity of the center driver? I have the Voxativ and I find it sounds much better more detailed with the polarity of the Voxativ flipped. I'm guesing it blends better or I messed up when building the XO from scratch.

I agree with Legolas, upgrading the caps can bring some nice results. Worth trying different resistors too.

I did change out the Mcap with a huge Clarity cap and it was a very positive improvement in articulation in bottom end. I second that, if nothing else would change that cap.

 

I've been trying to trace the capacitors for the mids and highs. I put together this diagram and thought it might be helpful for those of you with the Coax 10 Trio. The green/yellow lines are the resistors, grey are the caps, and brown is the inductor.

 

I've been trying to trace the capacitors for the mids and highs. I put together this diagram and thought it might be helpful for those of you with the Coax 10 Trio. The green/yellow lines are the resistors, grey are the caps, and brown is the inductor. View attachment 144747

First post on What's Best........

I've had my Quintets with Horn1 and Voxativ 1.6 for nearly seven years now. During the summer of 2018 Ze'ev offered the deal of a life time--Quintets with Horn1 and Voxativ 1.6, along with all crossover components for both mid-range drivers. The same package today would cost an extra six grand! I have experimented with various upgrades including caps, resistors, inductors, wiring, multiple amps, and even a third mid-driver, the Decware FRX2, and here's where I have landed.

Mid-Driver: Voxativ 1.6
Wiring: Completely wired with Duelund DCA 16.
DCA 12 from First Watt J2 to Vox 1.6.
DCA 16 from LFD NCSE to woofers.
Crossover: None on the Voxativ 1.6--they are being driven wide open by the First Watt J2
Only 10 mH inductors fronting the woofers
Frame: 3/8" thick ISODAMP washers between baffles and frames

For me, the most significant improvement was realized when the crossovers were completely removed. I knew the Vox 1.6 was a very good mid-range driver, but I didn't have a clue that the Voxativ would prove to be an incredible full range open baffle driver. As excellent as Ze'ev's stock crossovers are, and made even better with upgraded parts, the Voxativ drivers, IMO of course, are very much limited by a crossover. They are so good on their own that I will never handicap them again with a crossover. Regarding the woofers, having only a single coil fronting them has significantly elevated their performance.

I never could get the Horn1 to come to life; they always sounded lifeless and boring, no matter what amp and crossover parts I used. The past three years they have been sitting on my spare parts shelf. The Decware FRX2 driver is very good, but it is limited in output; it was not designed for a system like the Quintet.

Duelund speaker wire, to my ears, is as good as it gets at reasonable cost. Total re-wiring with Duelund runs into hundreds of dollars, which is not much money, relatively speaking, but that wire simply makes music sound real, right, natural, and live.

Frame ringing was almost entirely eliminated with the big ISODAMP washers, and frame vibration was reduced, though not entirely eliminated.

Quintets are amazing speakers when it comes to customizing and modifying. Mine are now in a place where I find the sound quality to be phenomenal.

 

First post on What's Best........

I've had my Quintets with Horn1 and Voxativ 1.6 for nearly seven years now. During the summer of 2018 Ze'ev offered the deal of a life time--Quintets with Horn1 and Voxativ 1.6, along with all crossover components for both mid-range drivers. The same package today would cost an extra six grand! I have experimented with various upgrades including caps, resistors, inductors, wiring, multiple amps, and even a third mid-driver, the Decware FRX2, and here's where I have landed.

Mid-Driver: Voxativ 1.6
Wiring: Completely wired with Duelund DCA 16.
DCA 12 from First Watt J2 to Vox 1.6.
DCA 16 from LFD NCSE to woofers.
Crossover: None on the Voxativ 1.6--they are being driven wide open by the First Watt J2
Only 10 mH inductors fronting the woofers
Frame: 3/8" thick ISODAMP washers between baffles and frames

For me, the most significant improvement was realized when the crossovers were completely removed. I knew the Vox 1.6 was a very good mid-range driver, but I didn't have a clue that the Voxativ would prove to be an incredible full range open baffle driver. As excellent as Ze'ev's stock crossovers are, and made even better with upgraded parts, the Voxativ drivers, IMO of course, are very much limited by a crossover. They are so good on their own that I will never handicap them again with a crossover. Regarding the woofers, having only a single coil fronting them has significantly elevated their performance.

I never could get the Horn1 to come to life; they always sounded lifeless and boring, no matter what amp and crossover parts I used. The past three years they have been sitting on my spare parts shelf. The Decware FRX2 driver is very good, but it is limited in output; it was not designed for a system like the Quintet.

Duelund speaker wire, to my ears, is as good as it gets at reasonable cost. Total re-wiring with Duelund runs into hundreds of dollars, which is not much money, relatively speaking, but that wire simply makes music sound real, right, natural, and live.

Frame ringing was almost entirely eliminated with the big ISODAMP washers, and frame vibration was reduced, though not entirely eliminated.

Quintets are amazing speakers when it comes to customizing and modifying. Mine are now in a place where I find the sound quality to be phenomenal.

Hi,

Can you run this a little bit slower please. So you connected the Voxative directly to your amp and the bi-amp (i guess) the woofer driver with just a "reduced" crossover?

 

A buddy of mine recently installed the Stack Audio AUVA 100 footers on his Duets. He was thrilled with the result.

I had already had my eye on the AUVA 100s, after his report I went ahead and placed an order.

WOW! the difference from the Wave Kinetics footers was staggering. Three days later and I'm still gobsmacked!

The soundstage expanded in all metrics. The real standout to me is the holographic and envelopingness.

 

Hi,

Can you run this a little bit slower please. So you connected the Voxative directly to your amp and the bi-amp (i guess) the woofer driver with just a "reduced" crossover?

Sure. My Decware CSP3 preamp has two stereo outputs. One output feeds a First Watt J2 (or sometimes a Cary 300SEI) which drives the Voxativs wide open--no crossover at all. The other output goes to my LFD NCSE which drives the eight woofers. The four woofers on either side are being cut off by a single 10 mH inductor for a 6 db per octave roll off at 120 hz.