I'm getting there!

[Lex]

I just wondered if you realized the sonic impact of all those beer cans on the coffee table? :LOL:

Nice work Pete!

Lex




Cable Guy DVD Collection

[Hank]

Pete: Lookin' good! The beer can sonic diffusers probably attenuate the back wave just enough, right?

[JonMarsh]

Pete,

Just out of curiousity, did you do any measurements comparing the dipole and monopole versions? I'd expect the monopole to have a bit of a fatter low midrange, due to lack of dipole cancellation, without some correction in the crossover. This might make it sound a little less accurately balanced. Did you have a chance to compare the two with the response equalized on axis for the same response balance? Inquiring minds are curious... but let's face it, what counts is getting the end results you want.

Best regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[PMazz]

Well, you guys beat me to it. I wasn't ready to release my findings, but what the hell.

The beer can tweak:

1st beer: No appreciable difference, regardless of the 1/2 full 1/2 empty debate.

2nd beer: Midrange starts to tighten up a hair, no big whoop.

3rd beer: Now we start to see some bloated midbass. Nothing we haven't dealt with before.

4th beer: OK, now we're into some serious differences. Everything starts to sound better....even the wife!

5th beer: Still sounds great, but who really cares, anyway. Sing-a-long tunes are my personal favorite from here on out.

6th beer: Now the soundfield has totally collapsed. My singing has gotten so loud that I didn't realize the song ended 5 minutes ago.

7-12th beer: Now we're into the Double Blind portion of the testing. I have no recollection of the conclusion of the test so I can't comment. But, from what I do remember, my gear never looked so good!


Jon, I haven't done any testing yet of this combination, but I will post the various FR curves when I do. Hell, I didn't even set up the mic to set the xover levels....just winged it.

On a brighter note, 2 feet of snow piling up has me thinking about a back operation!

Pete

[Jack Gilvey]

:LOL: Great post! :LOL:

[Hank]

Guys, I'm sorry I got Pete started... :roll:
We'll try again next week.

[Lex]

LOL Pete, your welcome for the assist.

Really well said. :LOL:

Lex

[JonMarsh]

By next week (or tomorrow) having finished the 12th can of beer to avoid the two feet of snow, he probably won't even acknowledge (or remember) that he made the post! :B


-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Jack Gilvey]

I just finished shoveling that same two feet of snow. Now onto the first beer.

[PMazz]

My snow now has now turned a lovely shade of yellow.....

Pete

[PMazz]

Finally set the test gear up and balanced the levels. I actually got pretty close by ear, only a couple Db here and there.

Jon, here's the comparison of the sealed RD50 vs dipole, both using sealed CSX10. Green is sealed and blue is dipole.



This is a very informal set of tests. The mic location was a little off, I'm sure, and they were done months apart. Not exactly a controlled test....

Pete

[JonMarsh]

Interesting data, Pete; thanks for the update. Were these measurements done on axis, or slightly off, and at what distance?

Both seen to show a consistent rise in the presence region- I wonder if some further tuning on the notch filter design would be useful? I plan to meaure my RD-50's in the final cabinet and refine the notch design using LSPCAD.

Went out looking at saws today at the Woodcrafter's in Dublin- unfortunately, they didnt' have a DeWalt DW746 on the floor- but I talked with some of their people and took a look at some of the other nice stuff they have. It's good having one of these stores in the area. Still, it will be a few more weeks before the doctor will give me a full physical release and I can consider getting started...


-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[PMazz]

Jon, as far as I remember, the sealed was taken from the listening position, at ~10'. The latest test with the dipole was done at ~6'. The speakers are toed in quite a bit, so from the listening position maybe only a few degrees off axis. The dipole was taken directly on axis.

Glad to hear you'll soon be "back in the saddle". Even if you're just in the talking about and shopping for tools mode, it won't be too long before the dust starts flyin'.

Regarding the notch filter, I'll be all ears. (eyes?)

Pete

[JonMarsh]

I'll keep you posted as to what develops.

I'll possibly build one "crude" test enclosure so I can start doing acoustical work on this system first.

But I've also got a two way 8" floor stander to build by the end of May when the Northern CA DIY speaker meet will be held at MarkK's, so I'll probably have to get going on that first. It's going to be a very busy three to four months coming up, what with some travel already in planning, and a couple of conference papers for at work!

Actually, other than a few muscle spasms yesterday (the first day I tried going without my brace), I've been pretty frisky feeling, actually have to remind myself a bit that I've still got a while to take it easy... haven't even taken motrin in weeks! That and getting a bit more sleep certainly helps!

Maybe if I find it's possible to come up with a more optimized notch filter, you could drop it in, too, and see if it helps smooth things out.


Best regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[PMazz]

Another 8" 2-way? What's this one going to be called, the MK XXIII?

Pete

[JonMarsh]

Yeah, Pete, I can just imagine what they're going to put on my headstone once I eventually pass away,

"Here lies the King of Eight Inch Two Ways"

And I'll be buried with whatever were my most recent ones. :LOL:

There's a little about what I'm considering/planning to do in the Avalon Klone thread, but I'll probably start a separate thread regarding them shortly. The tower enclsoure will allow optimizing low end extension to the low mid 20's, and of course, eliminate the need for stands! Plus, I hope they'll be purty.... 8)



These will probably be called something truely original, like "M8ta" for M8 design in Tower with Aluminum tweeter (I've got a couple of pairs of Hales Transcendence tweeters, and I'm angling for another set. These tweeters have an Fs at the same frequency as the Vifa XT, and overall similar impedance, plus they've got a beautiful long throw underhung motor (sounds more like a woofer, huh?) and the response extends below 1 kHz). Or, they'll just be called the "M8 MkV Limited Signature Edition" if I'm in the mood for a long and pretentious title. :W

When I finally get a new saw (expected sometime in April) this will be my "learning" project for it, (before I tackle the line arrays), and give me something interesting to take to the Northern CA DIY Speaker meet in CA the end of May.

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[PMazz]

The tower enclsoure will allow optimizing low end extension to the low mid 20's

A 2-way 8" with that kind of extension?

Are you hiding something in the bottom of that tower that you're not tellin' us?

Pete

[JonMarsh]

You Betcha- a big old long 3" flared port!

See my M8ta post for more details. 100 dB at 1 meter at 24 Hz with 25 watts...

Best regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Dennis H]

What happens when Pete's speaker and Jon's speaker fall in love and have babies? :LOL: :LOL:

http://www.harmonicdiscord.com/forums/viewtopic.php?t=10252&start=0

[ThomasW]

I think it's best not to comment on variations of Brian Cheney's designs, especially those with a single pivoting super tweeter......




theAudioWorx
Klone-Audio

[JonMarsh]

Now that's a woodwoorker's dream challenge, ...or nightmare!

Interesting look, I picked up on the Cheny angle right away due to the angled planar super tweeter, before reading Thomas's comment.

Now, this is an interesting shape and design- but where do I put my 8 6-1/2" drivers that I plan to use in MY line array? :?:

Can't just point 'em backwards or anything... and I really don't believe in running RD's down to 250 or 150 as some folks say...

This is a real hybrid- a partial line array for some frequency ranges (very upper mids through low treble), but it's gonna have a significant change in balance depending on the listening distance, matching that with point source midwoofers. So what distance do you tune it for?

These make my towers look like a walk in the park in comparison, regarding wood working difficulty. Fits right in with my previous comments that there's lots of things you can design in a CAD program and may have one heck of a time building in the real world. Have to find some balance on that.

I don't think even a ShopBot would help with these!

-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[Hank]

This is a real hybrid- a partial line array for some frequency ranges (very upper mids through low treble), but it's gonna have a significant change in balance depending on the listening distance, matching that with point source midwoofers. So what distance do you tune it for?

Just what I was thinking, after you Grand Poobahs having educated me on this forum about the line source/point source SPL/distance curve differences. This speaker would perhaps be too exacting in sweet spot location. A nice conversation piece though.