V8 Fonken design ?

[Bigun]

Well, those of you familiar with the great Fonken family of designs from planet10 will recognize this design - it's a 'nod' to Dave for sure

And if Dave has time to pass comment I'd be grateful - I've tried to produce a design with the minimum possible width and depth for a traditional Fonken cabinet as this better meets the constraints I face for in-room HT installation.

[planet10]

:^)

Turning the box sideways without moving the champhers might produce some weird results...

dave

[Bigun]

Hi Dave,

Can you say why the chamfers would be a problem ?

Even with my squashing the depth down from the regular Fonken I'm thinking it's probably unsuitable for horizontal mounting, there's simply too much weight to cantilever to put this on a wall and I'm not sure that the appearance of this design works so well horizontally. I'm going to play with this a bit more, but would love your thoughts on whether the ports would work if they were folded as in: http://www.diyaudio.com/forums/showt...55#post1722155 ? - after all the fancying around I'll probably do a simple box based on this if you think it's a go.

I have gone back to the Fonken-tuned floorstander as it is a shallower design. I'd really like to know a bit more about the port design. The cross section of the port is not nearly as 'thin' as the regular Fonken so it won't have the same level of 'resistance'. I assume this is because you were limited by the width of box. I would like to know if you think it's worth trying to accommodate a port that is thinner ? The attached drawing shows one way that I can see for doing this and at the same time I need to move the port to the front to allow wall mounting. Do you think this has a chance of working (no doubt you have built and tried many different configurations) ??

don't pay too much attention to the curved front, it was a thought experiment as you say and it could just as easily be flat. I do think it can be made curved but that's not the point - still trying to understand the consequences of tweaking your designs to suit my application.

[chrisb]

Gareth - I'll let Dave answer most of your "technical" questions, but in the meantime, I'll offer the opinion that any potential benefits of curved baffles would be offset by the complications of fabrication of enclosures of the aspect ratio of the Fonken series, and most specifically, the mounting of the driver .

It would certainly not be impossible, but I think would definitely add a degree of difficulty to the build, particularly as your drawing appears to imply a recessed, flush mounting.

[planet10]

Originally posted by Bigun
Can you say why the chamfers would be a problem ?

They are best all the way round the box, but if you are only doing 2 they should be on the sides....

As to whether tihe idea in the 1st post would work... in the Fonken167 we scored big time...

but would love your thoughts on whether the ports would work if they were folded as in: http://www.diyaudio.com/forums/showt...55#post1722155

I don't see any ports at all in that picture.

I have gone back to the Fonken-tuned floorstander as it is a shallower design. I'd really like to know a bit more about the port design.

The FS is probably the most compromised sonically (but it is no slouch -- we listened to a pair quite extensively yesterday (with FE127eN)). To keep a tall skinny box like that from becoming too much of a TL the vent needs to open up near the middle. To get the bass reinforcement of the port, it needs to exit at or near the floor (and or wall), to make it simple you want only one.

You could add a 2nd port and half the depth and end up with something interesting.

(no doubt you have built and tried many different configurations) ??

Thot of many, drew many of those (you variation included), released a fraction. You need to drop by and look over my shoulder while i flip thru the variations in my CAD SW.

dave

[chrisb]

a few more personal observations / musings re the dimensions/location of slots and bevels

The array of port slots flanking the driver is for me an aesthetic thing - on the FE127E design, the enclosure is small enough that there's not much choice as to location, but on the FE167, it just "felt right" to arrange as shown. In fact, I would have been inclined to centre the driver in the slot array, but to maintain the driver's distance from the floor, that would have necessitated an ungainly additional increase in overall height - and as you'll notice from the fittings in the photo, these will usually have grille covers installed.

Now for the "musing" - it's my intuition that the ports integrate more cohesively when surrounding the main driver as closely as the enclosure dimensions allow.

Regarding the bevels, and baffle width - in my listening experience with the Milevas, another FE127E design which have a very wide/ shallow aspect ratio ( my own pair have a minor, mostly decorative bevel to the vertical edges), the depth of soundstage and imaging specificity suffers somewhat in comparison to any of the horizontally narrow Fonkens - the Prime clearly being the best of the group in this regard.

While typing this post, I briefly repeated an experiment we did in fact conduct a while back - I rotated my stand mounted Fonkens to lie on their sides (i.e. ports horizontal). The change in centre of driver from the floor is only a couple of inches difference, but the overall vertical component of the soundstage was noticeably diminished.

Disclosure: the front baffles and bevel panels of my current pair of Fonkens have been EnABLed ( by Bud ) , and the Milevas are not (yet?)

[Bigun]

Dave, that Fonken 167 looks really nice ! - the two sets of 4 ports looks just right (those on the right look like they go all the way through the cabinet), the whole unit has the 'right' proportions - has the plan for this been posted yet, I'd love to see it ? I can see what Chris means too here about the position of the driver amongst the ports.

The more I look the more I see that I simply don't like centre speakers. Chris - your observations indicate further compromises in performance. Like the majority on this forum, I'm more of a stereo guy myself. And horizontal speakers don't look 'right'. Of course, who said it had to be horizontal, I don't see any reason why I can't use another vertical speaker so long as it doesn't obstruct the screen - and this should be within my control easy enough.

So, With three floor mounted speakers I can ignore the tradeoffs of going with wall mounting shallow boxes (except the rear surrounds where I don't care as much).

The folded ports question - I referenced the wrong post, let me try again: http://www.diyaudio.com/forums/showt...89#post1718789

Interesting thought about eNable, I'm wondering how much further benefit could be gotten from a Fonken baffle, given that it is heavily chamfered anyway ?

designing and learning has the danger of being more fun that building my speakers

[raypalmer]

where can I find plans/specs for the fonken167?

[planet10]

Originally posted by Bigun
that Fonken 167 looks really nice ! - the two sets of 4 ports looks just right (those on the right look like they go all the way through the cabinet), the whole unit has the 'right' proportions - has the plan for this been posted yet,

Originally posted by raypalmer
where can I find plans/specs for the fonken167?

Eventually fullly detailed plans will be available by donation, For now i'm looking for some people to be beta builder to help me get the plans to that point.

Email me.

dave

[planet10]

Originally posted by Bigun
The more I look the more I see that I simply don't like centre speakers. Chris - your observations indicate further compromises in performance. Like the majority on this forum, I'm more of a stereo guy myself. And horizontal speakers don't look 'right'. Of course, who said it had to be horizontal, I don't see any reason why I can't use another vertical speaker so long as it doesn't obstruct the screen - and this should be within my control easy enough.

As long as you don't have anyway sitting way out of the sweet spot, i figure the best centre channel is a virtual centre channel.

dave