[josh358]

As I understand it, a simple arrangement of CD's won't give you broadband diffusion. You need a more mathematical arrangement for that, or a simple curve.

I've never known whether vertical diffusion was a good idea with line sources or not. The floor and ceiling images of a line source basically approximate an infinite line source, rather than having the acoustic properties of room reflections. Of course, we do normally hear reflections from both, but the aural effects would very much depend on factors like predelay and interaural correlation. So I don't know if it would make things sound better or worse, and haven't heard from anybody who's compared them. A standard QRD diffuser does only lateral diffusion, while a skyline diffuser diffuses both laterally and vertically. It would be interesting to compare them, and perhaps absorption as well. QRD's can be made easily out of styrofoam, styrofoam skylines are a bit more work but are also cheap and pretty easy, so it would be easy to experiment. Maybe I'll do it myself at some point, when I get my IVa's set up (hopefully soon, I finally finished painting and just have to take up the dropcloths, then I can start putting stuff back together).

[SteveFord]

Josh,
You got them repaired, I take it?

[medium jim]

Steve:

Josh is like a professional student, he will never get them finished  

Jim

[josh358]

Josh,
You got them repaired, I take it?

Not yet. I've considered setting them up many times, but what with renovations going on both upstairs and down, painting and dust, workmen traipsing in and out, and everything shoved into odd rooms like the kitchen it's hard to find a safe space to power them up and desock them. Since I couldn't listen to them anyway it didn't much matter. This way, I'll be able to listen to and examine them and figure out what needs to be sent back to Magnepan, though it will probably be both sets of woofer panels -- the fellow I bought them from wasn't having any trouble with them, but at that age it's hard to believe that delamination hasn't occurred. (I'm planning to do the Neo 8 mod, so no sense in rebuilding the midrange panels, but if I did I'd do them with foil. But no foil on the bass, when I mentioned that possibility Wendell said "Why mess with the best woofers ever made?" and I had to admit he had a point.)

[josh358]

Steve:

Josh is like a professional student, he will never get them finished  

Jim

I wish! These have been the renovations from hell -- supposed to take six weeks, took two years instead . . .

[medium jim]

Josh:

I commend you for your stick to itness with the IV's and know they will be amazing once back into your system.

Jim

[josh358]

Josh:

I commend you for your stick to itness with the IV's and know they will be amazing once back into your system.

Jim

Thanks, Jim. Was just looking again at various midrange drivers and debating the merits of the RD-50's vs. the Neo 8's. But thinking about what you're going to do gets circular after a while. It's a lot more fun to actually do it. (Also, I keep realizing that nobody makes the driver that I actually want . . . )

[medium jim]

Thanks, Jim. Was just looking again at various midrange drivers and debating the merits of the RD-50's vs. the Neo 8's. But thinking about what you're going to do gets circular after a while. It's a lot more fun to actually do it. (Also, I keep realizing that nobody makes the driver that I actually want . . . )

Josh:

As you like to remind all of us, Hi-Fi is a game of compromises.  Personally, I think you should restore your IV's back to their original glory and then do what Andy did and make a pair of Frankenpans that you can modify to your hearts content. 

Back to my room set-up, so far so good with the 6" move forward.  Funny thing is that I didn't have to mess with the toe-in whatsoever.  Everything just seems sweeter and more defined, even those real early pressed CD's from 1979 thru the early 80's.  Sure, I know that they didn't get properly mastered, even so, after a few minutes I relax into the music and all is good.

Jim

[josh358]

I find that Maggies sound better and better the further they get away from the walls. Not necessarily in the bass, but everywhere else.

The IVa's really are Frankenpans already, since the midrange/tweeter panel can be separated from the woofer panels (basically a matter of an extra pair of feet so the separated panels don't fall over). Here's a picture of IVa's with the woofers behind the mid/tweeter panels:

http://www.integracoustics.com/images/magnepan/T4A.jpg

That's the way I'm going to use mine, since it's the only way I can fit them and a projection screen into my room!

It also makes them very easy to modify/combine with other speakers, I've seen the woofers combined with various stats, including Mmlrot1's Martin-Logans, and with 3.x's (Norman M.).

The IVa can also be easily modified with the Neo 8's, the midrange slot is the right size so all you have to do is take out the existing midrange drivers and stick the Neo's in their place. They're a bit easier to modify that way than the IV's since the slot in the IV's will only accommodate 6 Neos, but you need 8 Neo-8's for the best frequency response.

Now, if someone will only come out with a line source plasma tweeter that I can put in the ribbon slot . . .

[Robin Hood]

The IVa's really are Frankenpans already, since the midrange/tweeter panel can be separated from the woofer panels (basically a matter of an extra pair of feet so the separated panels don't fall over).

What are Frankenpans? Sounds like Frankenstein's monster.

Does that also mean the Mini Maggies are Frankenpans already, since the midrange/tweeter panel is separated from the woofer panel?

[medium jim]

Mini Maggie's are not "Frankenpan's", Frankenpan's are made from either several different Magnepan's as in the case of Andy's, or where the panels have been redone with non-original parts/speakers.

Jim

[josh358]

Here are some pics of Andy's:

http://www.audioasylum.com/cgi/vt.mpl?f=mug&m=156422&VT=T

[Robin Hood]

Mini Maggie's are not "Frankenpan's", Frankenpan's are made from either several different Magnepan's as in the case of Andy's, or where the panels have been redone with non-original parts/speakers.

Jim

Andy's Frankenpans look interesting. Andy posted the following on the Planar Asylum:

"However, a few inmates have used 2 Tymp bass panels each side to augment their 3.X series speakers - hemholtz is one. IE. you have:
BBBMR ... RMBBB
- now this must be a spectacular sound!! :_)) "

Does the above configuration of 2 Tympani bass panels with 3.x series speakers fit the definition of Frankenpans? If so, does a configuration of 2 DWM woofers with 3.x speakers fit the definition of Frankenpans? If not, suppose you modify the DWM crossover with 3.x series speakers does that fit the definition of Frankenpans?

Sorry to be late to the party but I am interested to learn.

[medium jim]

RH:

Let me see, you know hemholtz, me think you know more than you are letting on....

Jim

[josh358]

Andy's Frankenpans look interesting. Andy posted the following on the Planar Asylum:

"However, a few inmates have used 2 Tymp bass panels each side to augment their 3.X series speakers - hemholtz is one. IE. you have:
BBBMR ... RMBBB
- now this must be a spectacular sound!! :_)) "

Does the above configuration of 2 Tympani bass panels with 3.x series speakers fit the definition of Frankenpans? If so, does a configuration of 2 DWM woofers with 3.x speakers fit the definition of Frankenpans? If not, suppose you modify the DWM crossover with 3.x series speakers does that fit the definition of Frankenpans?

Sorry to be late to the party but I am interested to learn.

I don't think there's an official definition!

[medium jim]

Josh:

I think Robin Hood is pulling our legs.

Jim

[SteveFord]

Isn't hemholtz that thing you do to get people to hock up their dinner? 
It seems a bit off topic but maybe it will help save someone's life so why not.

[medium jim]

Steve:

You're thinking of the hymlick manouver. Hemholtz is the moniker of a guy on the asylum.

Jim

[kevin360]

Isn't hemholtz that thing you do to get people to hock up their dinner? 
It seems a bit off topic but maybe it will help save someone's life so why not.

Actually, I've always wondered if that moniker was intended to be 'helmholtz' instead - as in Helmholtz resonator. By the way, I like your present tagline. I'm sure you've heard Frank's poodle lecture (YCDTOSA6, disk1, track2) - funny stuff.

[oboaudio]

I find that Maggies sound better and better the further they get away from the walls. Not necessarily in the bass, but everywhere else.

The IVa's really are Frankenpans already, since the midrange/tweeter panel can be separated from the woofer panels (basically a matter of an extra pair of feet so the separated panels don't fall over). Here's a picture of IVa's with the woofers behind the mid/tweeter panels:

http://www.integracoustics.com/images/magnepan/T4A.jpg

That's the way I'm going to use mine, since it's the only way I can fit them and a projection screen into my room!

It also makes them very easy to modify/combine with other speakers, I've seen the woofers combined with various stats, including Mmlrot1's Martin-Logans, and with 3.x's (Norman M.).

The IVa can also be easily modified with the Neo 8's, the midrange slot is the right size so all you have to do is take out the existing midrange drivers and stick the Neo's in their place. They're a bit easier to modify that way than the IV's since the slot in the IV's will only accommodate 6 Neos, but you need 8 Neo-8's for the best frequency response.

Now, if someone will only come out with a line source plasma tweeter that I can put in the ribbon slot . . .



Line source plasma which goes down to 300 hz!