Bipolar miniOnken and source of Canadian supplies

[binarywhisper]

I've searched the Bipolar miniOnken and come up with very little info, in fact it is only referenced in a couple of threads. I'm interested in opinions about its sound.

I have a pair of NOS Radio Shack Dipoles that I hope to use with them x-over'd at somewhere from 10 to 13K.

I also would like to know where you Canadian guys are buying supplies like caps, silver wire and stuff like that. Solens only seems to list their own house brand of caps and I didn't see silver wire listed at all.

Any suggestions of any type are welcome.

[Scottmoose]

Well the plans are here: http://homepage.mac.com/tlinespeaker...O-0v91-map.pdf Should basically sound like the regular Fonken, but with a more spacious sound and a complete erradication of baffle-step, so stronger LF.

[binarywhisper]

Well I saw the plans and one of the things that appeals to me is that the cavity at the bottom, the sand cavity, is plenty big enough for some small subs to work in. My intention is to build them with out the sub and see what I think.

So has no one built a set yet?

How about Canadian suppliers for x-over parts and silver wire?

[vinylkid58]

Originally posted by binarywhisper
Well I saw the plans and one of the things that appeals to me is that the cavity at the bottom, the sand cavity, is plenty big enough for some small subs to work in. My intention is to build them with out the sub and see what I think.

So has no one built a set yet?

How about Canadian suppliers for x-over parts and silver wire?

I have built single driver Mini Onkens based on the Planet_10 design, with a bit more volume and vent area. I have seen and heard only one pair of bipole Fonkens, they sounded nice but I prefer the single driver version.

Caps and wire here:

http://www.partsconnexion.com/

http://www.takefiveaudio.com/

Jeff

[binarywhisper]

thanks for the links, thats exactly what I needed.

I already have some 125FR's and like them quite a bit. I've had them in many configurations but currently have them in a small heavily damped ported box running full range with a dipole tweeter sitting on top and a 12" woofer in a sealed enclosure with a coil x-over @ 300hz out of phase.

I find the tweeter and woofer really fill out the sound significantly. Adds the sparkle and the grunt and prehaps as importantly I get enough spl out of them to make it more then a near field solution.

They are currently very listenable but I would like more spl and I still find the sound stage a little small and distant. The speakers do not completely disappear as they should.


With the extra 3db I'll get from the bipolar design I can remove the l-pad I have on the dipole tweeter simplifying the design in the process.

What is the sound stage like with the minionken? Do the speakers disappear?

[vinylkid58]

Originally posted by binarywhisper

What is the sound stage like with the minionken? Do the speakers disappear?

Soundstage with the Fonkens is very good, depending on source and program material. This is with modified Fostex Fe127's of course, and after a decent break-in period. It's been quite a while since I listened to the FR125 based Onkens, but I'd expect the soundstage to be pretty close (monopole versions).

They come pretty close to disappearing, considering that you are listening to a single driver in a box. The trick is to keep that quality when adding more speakers to cover bass and treble.

I think you're concept of having bipole FR125's, powered subs in the bottom, and a tweeter on top is a good one. It's just a matter of fine tuning with XO points etc.

Jeff

[chrisb]

Originally posted by vinylkid58


Soundstage with the Fonkens is very good, depending on source and program material. This is with modified Fostex Fe127's of course, and after a decent break-in period. It's been quite a while since I listened to the FR125 based Onkens, but I'd expect the soundstage to be pretty close (monopole versions).

They come pretty close to disappearing, considering that you are listening to a single driver in a box. The trick is to keep that quality when adding more speakers to cover bass and treble.

I think you're concept of having bipole FR125's, powered subs in the bottom, and a tweeter on top is a good one. It's just a matter of fine tuning with XO points etc.

Jeff

allow me a couple of comments:

Adding an additional rear firing (or in your case dipole) tweeter can certainly aid in the illusion of ambience, but be careful considering a full range bipole or open baffle for that matter, unless you've got at least 3 or 4 feet of clear space available behind the speaker location, and several to the sides as well. They'll certainly fail to elicit their potential "magic", and you could be disappointed for the wrong reasons.

The mono pole mini-onken / Fonken design accomplishes a reasonably good compromise between the box "disappearing" and clean although subterranean bass response. Midrange imaging and soundstage width is quite remarkable.

If you haven't already investigated cone treatments for the FR125's, you might want to contact Dave about some experiments he's made.

Even after at least 6 pairs, the Fonken is not the quickest build in the world. If you'd like to try a much easier proof of concept, the more conventional flat panel design that Dave refers to as the "GR Fonken" comes pretty darn close to the performance of the original. Unless you're determined to execute gallery quality woodworking, they should take less than a day to put together.

As to addition of woofer(s)/sub(s), that's very much a personal choice - I've yet to find an easy to implement and entirely seamless design that doesn't dramatically change flavor through the pass band. In addition, my main listening room is tiny enough (approx 240 sq ft), that it's more trouble than it's worth. By the time you add enough bass traps to deal with standing waves and compression, etc, the room is too small for more than one listener, and what's the point if you can't show it off?


However, I know that Dave has some designs for incorporating actively powered woofers into a pedestal base for the main speakers that would reduce some of the clutter. Since the monopole design is essentially a large bookshelf sized box, and requires a stand of some sort, why integrate the woofers? I'll have to try a pair of those myself some time.

[chrisb]

Originally posted by chrisb


The mono pole mini-onken / Fonken design accomplishes a reasonably good compromise between the box "disappearing" and clean although subterranean bass response.

oops, I didn't catch the above type in time to edit the post - obviously that should say "although NOT subterranean bass response"

No doubt an appropriately sized "onken" style woofer / sub enclosure could be designed to achieve that, but it wouldn't be both small and efficient.

[vinylkid58]

Originally posted by chrisb
No doubt an appropriately sized "onken" style woofer / sub enclosure could be designed to achieve that, but it wouldn't be both small and efficient.

How about 111 liters, 92dB efficient and tuned to 38Hz. Some might say that this is an appropriately sized Onken.

Jeff

[binarywhisper]

Originally posted by chrisb


full range bipole or open baffle for that matter, unless you've got at least 3 or 4 feet of clear space available behind the speaker location, and several to the sides as well.

my living room is pretty average size 17' x 17' (289 sq ft) and I've never minded pulling the speakers out into the room when I do more serious listening.

There are functionally no corners in the room and the wall opposite is floor to ceiling bookshelves that are surprisenly good at eating deflections. I'll be spraying the acoustic ceiling sometime this month. All in all its a very well damped room with very few problem spots and with a little tweaking it will get better.

on a side note, I live in a small, 1200 sq ft, house and the wall to ceiling bookshelves I built in the living room back onto floor to ceiling closets running the full length of the main hall way. Bottom line is that wall is now 42" deep. I can play music at very high levels and my light sleeper wife is out like a light 20 ft away. Very cool

Midrange imaging and soundstage width is quite remarkable.

well that is probably my primary concern.

If you haven't already investigated cone treatments for the FR125's, you might want to contact Dave about some experiments he's made.

I was not aware there were any treatments for the 125's. Thats interesting. Dave??? U there

However, I know that Dave has some designs for incorporating actively powered woofers into a pedestal base for the main speakers that would reduce some of the clutter. Since the monopole design is essentially a large bookshelf sized box, and requires a stand of some sort, why integrate the woofers? I'll have to try a pair of those myself some time. [/B]

Well that was more or less my original idea but I would really like the extra 3db I'd pull from a 2nd 125 as well as BStep elimination, removal of the Lpad on the tweeter and the push push config offers several benefits as well.

I guess this design claims to remove the BStep requirement due to the heavily chamfered front baffle though eh? mmmm .... what if I placed both 125's on the front baffle