My 'Moon-Onken'

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#81
vinylkid58 said:


Those big boxes look quite lovely Chris. It's plainly obvious you've got the veneering down to a fine art. Too bad you couldn't do the inside of the vents, but I'm guessing that may not work with the type of veneer you're using.

Jeff
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Thanks, Jeff - I definitely got the inspiration from your own build. Yes,
"post" veneering the slots would be tricky indeed - this pair of boxes was a reclaim of original pair of plywood prototypes built about 3 yrs ago.

It would certainly be possible to veneer inside the slots during assembly, but I generally paint them out if they're not going to be natural finish. In any case, I think the veneering detail would mostly get lost since the slots tend to get cast with shadows except if under direct lighting (such as camera flash).
 
#82
HareBrained said:
[You could always "butterfly" the ports of the fonken putting them on the back, yielding a wide and shallow version suitable for hanging.
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Sort of like this?

WallFonken-take3-sketch.gif


The thing we worry about with these are the effects of the proximity of the back wall of the box and early reflections back thru the cone.

dave
 
#83
You know, Dave, et all. You guys need to cease and desist from posting speakers looking like that. Its bad enough you make me feel like I am not even trying but the worst part is next thing you know my wife comes into my study while I am looking at one of your speaker pics and begins to question as to why the speakers I seem to be always building never come out half as good looking:bawling:
 
#84
HareBrained said:


You could always "butterfly" the ports of the fonken putting them on the back, yielding a wide and shallow version suitable for hanging. You could orient the ports vertically for better aesthetics. The ports could also be interlaced for narrower and taller configuration if you believe you have to have them exiting out the sides.
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Be aware that in some of our playing around, we found not so subtle affects on imaging and midrange/upper midbass clarity with either wider baffles / shallower cabinets, or changes in orientation of vent slots.

Dave and others have conceived/drawn more variants than I think have actually been built, so who knows?

edit - I see he beat to the go button again


It's been my experience, that wallmount/inwall installation can create more problems with imaging and "sweet spot" than they're worth.
 
#85
planet10 said:

Sort of like this?
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Close to my fave style wall and wall/floor 'pancake' design except the baffle curves, or at least flat angles, away beginning at the driver flange with vent depth = side depth. Of course unusable if drivers require much toe-in, but I always used a super-tweeter, so never felt the need. Note too that such speakers were for FM, vinyl, cassette tape casual listening, never intended to be for the kind of critical listening some folks do with minimalist systems.

For drivers requiring toe-in, offsetting the driver to create the desired angle should work.

WRT mid-range/upper mid-bass clarity with vented alignments, the pioneers of audio found that placing the driver inside a tube that was in turn the inside of the vent tube or 'ringing' the driver with many small vents as an acceptable variation was the most acoustically efficient which in turn minimized driver/vent crosstalk (comb filtering) due to the vent's high Q decay, so has anyone tried either yet?

GM
 
#86
dublin78 said:
These Moon Onkens look just like what I am after for my FX120eN drivers. Congratulations.
I will be using a pair of subs, so low end issues are not too important. My main criteria are small size and wall mountable ability. Oh, and getting the best midrange available.
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Hi Dublin78,

Here's my take on the situation. First off, looking at the driver specs, the Moon Onkens would work perfectly. The driver specs are pretty close, the main difference being the Vas which influences box size a bit. But I would say that bass extension is not the issue here because you will be using subs.

I spent some time refining the size of the Moon Onkens as they are for an HT application and at least one pair will be wall mounted. I looked carefully at shallow boxes but in the end I decided against them. There are several reasons for this, a) I don't like the aesthetics, b) they restrict the internal port design options for this type of Onken, c) I was concerned about sound reflections of the back of the box if too close to the driver, d) you can get other effects with long thin boxes, they start to look like transmission lines. e) for a shallow box you have to make up the volume in the width and height which I didn't want to do.

I also wanted to move away from the typical 3-slot Onken design, this was very much an aesthetic decision as it's just as easy to make it with 3 slots as 2. Lastly, in the future I may want them on a desk top or a stand. The shape and size were a major driver for aesthetics and this shape/size looks just right by my judgment.

The size of the box will work very nicely for wall mounting if you use a suitable bracket of course.

Yes, you do want the 'holey brace'.

Also, the design is close to some of Planet10 designs, so it's a safe bet that it works !

Feel free to email if you want some of the original design files.

And I have found that the sound depends on the amplifier. I have built my own, it has a tube-type sound from solid state that works wonders with the Fostex drivers !
http://www.diyaudio.com/forums/showthread.php?postid=1848651#post1848651


p.s. Dave and Chris have been building Onkens for a long time, have built more of them than I've had hot dinners; an off the shelf design from them (Planet10) is also a good option if you don't want to strike out on your own. Good luck !
 
#98
Nirvana,

that's a going to be a nice pair of speakers !

Dublin78,

the size of the box, in my humble opinion, is not too critical since the Onken ports, which are not too dissimilar from a Base Reflex, can be adjusted to suit. In fact, if you haven't done so already you should load up your driver spec into a BR calculator as it provides a close match to the type of Onken I built :http://micka.de/org/en/index.php#ideal

the main issue with box size will be how low a frequency you can get to.
 
#99
Bigun: I would like to have a stab at building some cabinets to the same scale as yours on post no.2 with the same Net Vb: 6.2 litres. I will keep all interior dimensions the same.

Dave: You are probably correct about 10litres being the minimum, but I would like to try some smaller ones. Afterall, I will be using subs. I could happily build a pair to your specs and compare them. I have plenty of plywood lying around.


I have tried to use the software off the previous post, but for some reason, I failed to get a result.

If I kept the port length the same 16.5cm, what changes to the ports (4 of them) cross sections would be needed for the FX120?

http://www.fostexinternational.com/docs/speaker_comp/pdf/fx120.pdf
 
#100
chrisb said:
Gareth - I haven't seen new posts from you for a while, if you're still interested, the new Mark Audio drivers (particularly the CHR70) are a helluva bargain; they sound quite decent dead stock from the box, and abso-bloody-lutely respond well to the EnABL process.

Based on experience with 3 models of Mark Audio drivers to date, (Alpair 6 & 10, CHR70) the only caveats I'd declare would be that the sensitivity and impedance could create an issue for flea power amps of any stripe.

We're only starting to play with enclosure configurations on these, and it's perhaps premature to speculate on "best" 😉
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Hi Chris,

I've been busy learning how to design and build an amplifier for my Moon Onkens. Turned out to be a lot of work. You can find it here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=145652

and: http://www.diyaudio.com/forums/showthread.php?s=&threadid=146015

I like the look of the Mark Audio drivers. I expect to start another speaker project at some point this year. I'm thinking though, of a 2-way because I've never designed and built one before. Not yet sure if it will be a full-range + woofer with cross over down at 300Hz, or a more traditional mid-woofer + tweeter with a cross over at 2.5kHz. It will be new territory for me which makes in interesting. Another option that is on my list is a full range with a much larger xmax than the Fostex, in a sealed box, and then eq'd at the low end for extended response.

Dublin78,

I'll take a look at that link and see if it works with that driver of yours when I get a chance sometime in the next 48 hours...
 
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