They're running!

[mzisserson]

Got the "New Horizons" running tonight. These were my first attempt with PCD.

I am going to be captain obvious here, but PCD is indeed much more powerful than x-over pro. Though I am still a huge fan of Bass Box.

Biggest lesson so far: When accounting for driver spacing and listening position, as well as diffraction step and constructive/destructive interference, trust what PCD tells you. I has the tweeter padded nearly 6dB too much, which is how I use to account for this stuff for this stuff in x-over pro. It was the main reason I used a series resistor before the x-over, to be able to play around.

They are far from perfect, however I think I am in the ball park, and in the seating section of where these need to be, I just need to get in the seat. I will (hopefully) be putting a mic to these sooner than later.

I have to tell you though, regardless of what the mic says, they are darn impressive! They are similar to my reds in tonality, but are much more open and a little more laid back. The ND16 is a wonderful tweeter ad everyone knows, still getting together an opinion on the ND105...

If anyone from the DIY NE area with measurement experience would like to assist me in measuring these, I could use the help and learning experience.

[joekraska]

Re: They're running!

Congratulations.

[Mark65]

Re: They're running!

That looks great! Glad to hear that they worked out for you! Post those measurements when you get 'em!

mark

[Taterworks]

Re: They're running!

Hey Mzisserson,

Are the ND105s the excursion monsters that they look like? How's the bass sounding so far? If it weren't for their highish Qts (sealed box), I'd be all over them like white on rice.

[mzisserson]

Re: They're running!

Hey Mzisserson,

Are the ND105s the excursion monsters that they look like? How's the bass sounding so far? If it weren't for their highish Qts (sealed box), I'd be all over them like white on rice.

Well,
A fellow audio guy round here Nat is going to be kind enough to let me use his external sound card to get some measurements done. They will likely be crude, in-room type at first until I practice up on better, more accurate measuring. I am in the middle of "testing loudspeakers" at the moment as well, so I am likely ready to get measuring!

The ND105's are nothing short of amazing. They are xmax monsters, they are smooth as I have them crossed 2BW at 2250, and I am using them in a .15ft3 box with a 1.125"x6.5" port and I am getting in room response to 40Hz (easily produces low E on all stringed bass instruments with room filling authority). For as inefficient as they are, they pack a punch and do not seem "power hungry" i.e., they sound great at a whisper.

I took a shot looking at the well damped Qms, and the xmax/xlim and thought they would be well behaved in a vented alignment. So far all seems well.

The only thing I am missing with these seems to be the deep inner detail and the sorting ability of better (more expensive) drivers. I keep having to remind myself that its a $5 tweeter and a $25 woofer with a total build cost of >$100. I will have other ears on them this weekend, and I do not plan on buttoning up the x-over for a while, so the work will go on.

Thanks for all of the support and interest in my build!

Here is a link to the design goals, graphs, charts, and pictures.

I will likely update this along the way as I am using my blog as one place for all the build infor going forward.

[MSaturn]

Re: They're running!

Looks like a good cheap project. I'm glad someone is documenting the use of those new ND drivers.

My one suggestion would be to use the ND20FB-4 instead, because of its remarkably linear response and slightly lower distortion. Then again, in the nearfield, the rolled-off top end might be preferable. You use the phrase "room-filling", and in that case, a more linear upper octave or two might be satisfying. Also, I'd put those drivers closer together cause of that high crossover point. Is acoustic response actually third order? It looks like a damped electrical 3rd resulting in LR2 response in your graphs.

[brianpowers27]

Re: They're running!

I noticed you showed vent velocity at 30 watts. How does cone excursion look at 30 watts?

[mzisserson]

Re: They're running!

I noticed you showed vent velocity at 30 watts. How does cone excursion look at 30 watts?

Not too bad. Assuming you jam a 30W sine at that frequency, I show x-max reached at 40Hz, while Xlim (given by PE as 20mm I am assuming that is P-P) does not get streched until 33Hz. After xlim is reached the excursion seems to plateu only rising slightly with decrease in frequency, it does not jump off the chart like some woofers do. It is something I look for when modeling woofes. It seems the lower the Qms, the worse the unloading is past Fb.

One of the obvious sacrifices I was willing to make was loudness. I am very happy hitting in the high 80's dB in room, about 8' away with these. They do it well with everything from electronica, to classical. At my normal listening level which is 80-85dB in room, they are very clean, even when pumping like a stroked out 350!