My Current Project...(Teasers...)

[mattp]

I didn't post a complete x-over to try. (Yet) Here's something to look at. Here's your current xo, and my xo that uses a lot more parts. There's a voicing difference here that would be very significant. One is a bit laid back, (yours), the other is rather aggressive (mine). It's tough to know which is preferred, but once you listen, and see measurements of what you listen to, you get a pretty good idea where you want the response.

rpb,

There is a pretty significant difference there for sure. I like the added efficiency you show. I haven't used PCD in years, can you draw up a schematic and post? I may give something like this a try before I commit to anything. Weighing all options is never a bad thing.

[Wolf]

Bottomless trap (or a type of series notch) = LC across driver.
Infinite notch or tank (or parallel wired LC) = L||C in series with driver.

The tank has a way of allowing upper treble ripple through as the cap is also in series with the woofer. Usually, it's easy to suppress the ripple in the audible band. This does not mean there is no output above there ultrasonically. We just can't see the effects above 20kHz in most modelers. This can cause issues in some amplifiers as it might cause ultrasonic oscillation. Of all the amplifiers I've heard of others having over the years (solid state), I can count on one hand the amplifiers that have been reported as having problems. The normal fix is to have a 4-5 ohm resistor in series with the cap that is across the low-pass coil. It affects the tank's notch function minimally, and keeps the amplifiers in question happy. If you have a standard second order with the tank, and there is already a damping resistor in series with the shunt cap, usually the other resistor can be omitted. Just try to keep a circuit that does not trace; in - cap - cap - gnd. This will avoid the problems.

Glad this has been of assistance,
Wolf

[rpb]

rpb,

There is a pretty significant difference there for sure. I like the added efficiency you show. I haven't used PCD in years, can you draw up a schematic and post? I may give something like this a try before I commit to anything. Weighing all options is never a bad thing.

Here's a simple 6 part x-over that is voiced similar to what you are currently using.

[mattp]

Here's a simple 6 part x-over that is voiced similar to what you are currently using.

While I do lean toward simplistic crossovers I'm not against more components if it means getting better from these drivers. It's not every day you have this caliber of drivers to work with so I am all about getting the best I can. I know the woofer is a little tricky to work with and the facets added some dips in the tweeter response.

So many possibilities and so few crossover components to mock up.

[rpb]

This 6 part filter would be just a smidgen more laid back. Here's a comparison. Black line is my filter. Gray is jhollander filter. I'm not suggesting it's better. Just has a couple less parts. Although not intentional, it's virtually the same filter.

I'm working on another filter.

[rpb]

OK.. here's my best effort at performance with reasonable part count. Higher xo point. Slightly more forward voicing. Breakup is buried. Should sound good when the need to crank things up hits you. Oh, and just 11 parts!

[Wolf]

I count 12 due to a coil DCR being above 1 ohm. What I don't like is the 8dB droop in the top-end.

Later,
Wolf

[rpb]

I count 12 due to a coil DCR being above 1 ohm. What I don't like is the 8dB droop in the top-end.

Later,
Wolf

It's 11. Two fourth order filters is 8 parts. One padding resistor on the tweeter, one cap for the tank, and one resistor that I added in the woofer circuit. I didn't worry about the tweeter top end on this sim.

[rpb]

This is pretty much the same, but with a couple different parts.

[mattp]

Quick project update guys. I'm still voicing and still tweaking. I haven't had much listening time the last couple days but I should more this week. I appreciate all the help thus far.

I did manage to get a little more done on the stands. They are a bit generic but they should be solid and fit the aesthetic pretty well. As I said before the PVC will be painted an off-white and will be filled with sand. My estimate is roughly 30-35 lbs of sand per stand not including the weight of the other materials. I have yet to put the veneer on the edges but that will be the last step before poly and paint, then assembly. THEN SUBS...

[mattp]

Lots of tweaking to get the height right. These ended up being right at 23" high, plus an inch or so for the spikes. This should put the tweeters right at ear level in my LP.

[mattp]

These will be assembled with 1/4-20 all thread through each pipe so the 3/4" countersunk holes are for the lock nuts and washers.

It rained all day today so I am waiting for a dry day to sand and finish the bases and paint.

[andykriech]

Matt, no bevels across your top/base plates to mimic your bevels on the speakers?
they seem a little plain/blunt in comparison to my eye...
just my $.02
Andy

[mattp]

Matt, no bevels across your top/base plates to mimic your bevels on the speakers?
they seem a little plain/blunt in comparison to my eye...
just my $.02
Andy

Andy,

The angled corners will match the facets on the front but be straight down as opposed to angled inward. After playing with sketchup drawings and looking at both the straight angles looked a little better to me.

I feel like this will have a little better separation from the cabinets instead of looking like an extension of the cabinet making it look a little long and asymmetrical vertically. It should make more sense once you see them finished.

[andykriech]

Hi Matt, that makes sense. Can't wait to see them finished up.
Andy.