Having some fun on a lazy sunday afternoon

JoshK · « **on:** 2 Apr 2006, 09:13 pm »

I thought I'd take a couple snap shots of some of the wares I've been collecting for my speaker project (Arvo Pärt) and the balanced power project (Felix).

To give a perspective of size I took some photos of the Equitech Q in a Box 1.5kva balanced power tx next to one of my Plitron 500va power tx (w/ IS shield).

The Q tx is slated for a balanced Felix project. The Plitrons are for one of my many amp projects.

Next up, so fun comparing relative sizes of drivers...

This is a SEAS Excel W22 (8"), a TC2+ 12" and an Ascendent Audio Avalanche 15" (w/ XBL2 motor). The picture doesn't quite capture the difference in scale quite right as I am not a good photographer yet. I guess having a nice camera does not a good photographer make.

More aerial perspective for cone size comparison....

note: Paul correctly pointed out that I forgot the decimal place when I called the Q in a box a 15kva tx....what's a decimal place!

Now that would be a HUGE tx!

Gordy · « **Reply #1 on:** 2 Apr 2006, 09:44 pm »

Most excellent Josh! When will the Arvo be ready for a Ravo???

I've been busy as well! I'm about to post some pics to the UcD builders thread... looking for any layout / build improvements you can think of, thanks!!!

mcrespo71 · « **Reply #2 on:** 2 Apr 2006, 10:15 pm »

Don't forget to test out all your DIY projects with your treasured Diana Krall CD's, Josh!

Bemopti123 · « **Reply #3 on:** 3 Apr 2006, 12:16 am »

Josh, did you get rid of the VMPS? or are you waiting until the Parts will take their place? Man, you are rocketeering towards DIYer asylum. I call it almost like "molting" the regular consumer stage towards full maturity in the audio world. Once I should just continue aspiring to.

PS: I still remember that story about you attempting to fix up your place and when you went and sawed off something from the ceiling, to smell gas!

I am sure your house came along much since that rave we had at your place, almost more than 1 or 1.5 years ago.

Paul K.

JoshK · « **Reply #4 on:** 3 Apr 2006, 01:09 am »

I still have the VMPS's, but they are up for sale (one person is interested and arranging a time to come listen). I am mostly selling them to move on into further insanity of diy.

Yes, DIY is an adventure, both in audio and in home renovation. My house is coming along at a snail's pace. Basically we haven't been very motivated...

But little by little things are changing. The downstair's bathroom project has seen some decent headway, though, in the last couple weeks. It is getting pretty close to useable.

Right now I am on pause mode for all DIY projects because I am studying for another CFA exam. So no headway will be made till after June 3.

My wife is a little resentful of my diy audio projects, rightfully so because they steal time away from home renovations, but she is little better. What can you do?

Right now I have the RM40s and a pair of Modula MTM's for speakers and I don't plan to start working on the Arvo Pärts till after the exam. It will start with making prototype baffles and making lots of measurments so I can construct the xo's in the DEQX. From there I imagine it will be a while before they are "pretty".

JoshK · « **Reply #5 on:** 3 Apr 2006, 01:13 am »

By the way....the 15"s are for a sub project (I have two of them) not part of the Arvo Part speakers. The W22s (4) and the TC2+s (4) together with a yet to be decided tweeter (either RS28a or the Accuton C24-6) in an MCM waveguide will make up the Arvo Parts.

I do plan to have a rave once I get it all running, which is who knows when.

Bemopti123 · « **Reply #6 on:** 3 Apr 2006, 01:44 am »

Can't wait to see how your project will come along! I understand your wife with these things stealing your time from other more significant things, but how I should say "significant or insignificant" is in the eyes of the beholder. My comp and audio passions are "insignificant or irrelevant" for my wife, but what she does not get is that at least, I am not doing something more destructive to myself. I call it, my little sanity in an insane world.

PS: Not everything needs to be results or outcome driven, especially at home.[/code]

Bemopti123 · « **Reply #7 on:** 3 Apr 2006, 01:46 am »

Why did you name the speaker project Arvo Part? Does it have to do with his music or compositions or simply just because?

JoshK · « **Reply #8 on:** 3 Apr 2006, 02:55 am »

this will explain it some more....

http://www.htguide.com/forum/showthread.php4?t=7644

Its an ever evolving project that was a variation on Linkwitz's Pheonix. Basically the MTM portion of my variation will be different then that listed on that thread in terms of drivers but the format will be the same.

Bemopti123 · « **Reply #9 on:** 3 Apr 2006, 03:28 am »

Wow, Josh, that system looks like a beast. More like a Linkwitz design but on steroids. If it sounds as bad as it looks, it will be a killer.

brj · « **Reply #10 on:** 3 Apr 2006, 06:26 am »

Great looking project, Josh!

Everything I've read about the Orion and all of the derivative designs has been fantastic. Every so often I go back and read some more of Linkwitz's site, but I never seem to hit bottom! The only sticking point I've ever seen mentioned regarding the Orion, and other designs using un-enclosed drivers, is the need for a room that allows some real space behind the speaker positions. Ahhh.... more inspiration to feed the dream of a large, dedicated listen room!

Aside from the other benefits of a waveguide, I take it you are using it to lower the crossover point between the tweeter and the midrange? I would have thought the W22s too large otherwise...

How are you planning on forming the waveguide?

Please keep us posted on your project!

(Wow! I just followed your link - to the 15 page thread! I'll have to leave that reading for later...)

JoshK · « **Reply #11 on:** 3 Apr 2006, 02:41 pm »

Paul, when I get-r-dun I'll have you over to hear them.

Brian,

Like you said, there are issues with using such a large mid (8"), but Linkwitz also uses the W22 in the Orion. Jon Marsh, the man behind the Arvo Project is a crazy designer that leaves nothing left on the table. Take for example my Modula MTM's whose xo's cost about 50% more than the drivers! His Cauer-Elliptic filters would never survive a commercial product because of the cost involved, but the proof is in the pudding, and I simple think they sound great.

The Arvo in its passive form (actually as it stands now is all passive) uses the CE type 8th order filter. This allows the break up modes to be 50db down instead of what they would be with a 4th order. This means you can push the tweeter lower (but still need an uber robust tweeter) and the mid a little higher.

The WG allows the distortion to stay low (or so we hope) in the lower range when pushed to well over 100dbs. It also helps match the narrowing directivity of hte W22 in its upper end (keep power response smooth). The goal is to try to lower the tweeter xo to 1100 instead of the 1250hz now. This also allows the c-t-c spacing between the two W22s to be close enough to avoid the typical MTM lobing.

Most of the members of that board (mostly hard core diy'ers) are of the opinion that dipoles aren't any more restricted then any other speaker in terms of how close you can place them to the walls. They feel the downside is just as bad with close box speakers. That said, I know what SL has to say and iirc, the rule is about 3 to 1 b/w the listening distance from the speakers to the space behind the speaker and the wall. So they can be used relatively nearfield too.

The advantage of the dipole is that they load your room a lot less which is why I am venturing down that path, since I have such a crappy room.

brj · « **Reply #12 on:** 3 Apr 2006, 05:42 pm »

Sounds like a fun project, Josh!

I have to admit the purchase of a tool like the DEQ/X would be the tipping point for me to get significantly involved with DIY speakers. My curiousity about the design tradeoffs in speaker design have prompted a great deal of reading on the manipulation of filter networks, but so far my interests (and time limits) haven't yet led me to study the implemention of those filters using capacitors, resistors and inductors. Basically, the design methods, optimization, and results interest me more than the traditional means of implementing a given design. The DEQ/X, however, makes such filter implementations practically instantaneous, and provides quite a few additional options besides. I'll give such units a few years to come down in price, however, before I jump in. In the meantime, I'll play with computer software tools of similar purpose, such as BruteFIR, etc..

(I'm having visions of DEQ/X based final network testing following the pattern of an eyedoctor visit: Do you prefer network A...... or B? Network B.... or C?

)

By the way, how do you intend to fabricate the actual waveguide?

Do you have a feeling for how low the speaker will play? With dual 12" TC Sounds woofers, even in a dipole arrangement designed not to overload the room, I'm actually rather surprised that you'd need a sub.

JoshK · « **Reply #13 on:** 3 Apr 2006, 05:55 pm »

Well I don't remember the actual spec for low bass excursion limits. I think though that xmax is the limiting factor for low bass. I plan to use the subs for under 40hz only. They will get built into a very large ottoman, with push-push sealed configuration, or I'll obtain a couple more and go the IB route.

My wife was actually OK with the IB idea when I showed her a picture of someone's implementation that would be similar to ours.

In regards to the WG: First off, I have about 6 of the MCM wageguides. I basically will machine it down, like John Krutke did and attach a tweeter. Then I'll measure the results to see if I like it. A gentlemen I met on a diy forum has offered to make some WG's for use out of nice hardwoods when we finalize the profile we want. He is an ace wood spinner, it is just a matter of us working out the details.

_scotty_ · « **Reply #14 on:** 3 Apr 2006, 07:30 pm »

JoshK,Parts Express has wave guides of different diameters that are larger than the MCM wave guide. The angle may be shallower and a better impedance match may be possible between the dome and the horn.
See link: http://www.partsexpress.com/webpage.cfm?DID=7&WebPage_ID=3&Start=2&ObjectGroup_ID=564&sm=1&so=2
Scotty

JoshK · « **Reply #15 on:** 3 Apr 2006, 07:38 pm »

Scotty...I am familiar with those WG's as they are the same as the Steel Sound WG's. I have a pair of hte SS 7"ers. But they are 70º horns rather than 90º. They are also deeper then I'd prefer.

mgalusha · « **Reply #16 on:** 3 Apr 2006, 08:40 pm »

Nice Josh. I've heard some of Jon's work as ThomasW lives in town and I've been able to hear a couple of the things he's concocted. I'm betting these will sound very nice once you get them done.

JoshK · « **Reply #17 on:** 3 Apr 2006, 08:45 pm »

Mike,

Have you heard Thomas' Arvo Parts? He has a pair that are biamped. This was based on a different mid, but they are similar.