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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.
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.
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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/showthread.php?postid=1722155#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.
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/showthread.php?postid=1722155#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.
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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.
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.
Bigun said:
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...
I don't see any ports at all in that picture.
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.
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
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?)
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?)
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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/showthread.php?postid=1718789#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
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/showthread.php?postid=1718789#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
re Fonken 167
Gareth, there's a bit of an artifact in the angle of the photo and the camera flash - as with the "Prime" and "steens" the ports do indeed extend almost to the rear panel of the cabinets.
This pair was the initial prototypes, and the inside of port slots and back were not painted out before assembly - as a result, under certain lighting and viewing conditions, you can see through the slots to the back panel.
I just spent another afternoon at my sister's place for a family get together, and the speakers were playing throughout the conversation and dinner. A couple of the CDs playing were a reissue or compilation of Beatles and I think including the soundtrack from "Luv". I'm of the generation raised on original issues of this stuff, and these discs sounded almost completely unlistenable - thank goodness for the Australian Shiraz.
Gareth, there's a bit of an artifact in the angle of the photo and the camera flash - as with the "Prime" and "steens" the ports do indeed extend almost to the rear panel of the cabinets.
This pair was the initial prototypes, and the inside of port slots and back were not painted out before assembly - as a result, under certain lighting and viewing conditions, you can see through the slots to the back panel.
I just spent another afternoon at my sister's place for a family get together, and the speakers were playing throughout the conversation and dinner. A couple of the CDs playing were a reissue or compilation of Beatles and I think including the soundtrack from "Luv". I'm of the generation raised on original issues of this stuff, and these discs sounded almost completely unlistenable - thank goodness for the Australian Shiraz.
planet10 said:
Of course, the ideal might well be a high definition projector and acoustically transparent screen, with all 3 front speakers located behind.
I had an interesting discussion with an interior designer this morning regarding why, if construction budget allowed, a "client" wouldn't want a custom sound system with all speakers built into the walls / ceilings, and all components hidden, etc. It became quite clear that as far as she was concerned, once her design is complete, why would you possibly want to change anything, such as placement of furniture, etc. Further, what do you mean by "sound quality and imaging" etc., and how could placement possibly make a difference?
oh yes, and as far as colour is concerned - well if you have to see the speakers, then why not black? - it goes with everything - and is slimming too?
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Chris, are you sure that photo isn't showing a mock up of an open baffle design, disguised to look like a Fonken (the game is given away by the 'see through' ports) ?!
Anyhow, seems like we're heading away from horizontal speakers for my HT system to a purely vertical arrangement. For the rear surrounds that is a bit tricky because I have to accommodate them on brackets supported from the ceiling with the vertical edge of a bulkhead (hiding a steel lintel) directly behind them; this gives me about 12" of height to play with. Hmmm, that mFonken is looking like a better fit...
In boxes with volumes much smaller than the regular Fonken the tuning requires a shorter port length and I would have thought to keep overall port 'resistance' the same the port requires a higher aspect ratio ? If so, what should it be ?
LOL on the interior design tips
Anyhow, seems like we're heading away from horizontal speakers for my HT system to a purely vertical arrangement. For the rear surrounds that is a bit tricky because I have to accommodate them on brackets supported from the ceiling with the vertical edge of a bulkhead (hiding a steel lintel) directly behind them; this gives me about 12" of height to play with. Hmmm, that mFonken is looking like a better fit...
In boxes with volumes much smaller than the regular Fonken the tuning requires a shorter port length and I would have thought to keep overall port 'resistance' the same the port requires a higher aspect ratio ? If so, what should it be ?
LOL on the interior design tips
Bigun said:
I have very limited experience with anything higher than the front 3.1 of surround, and that was several years ago. When I was contemplating it for my own system, the room in question and seating position would have only permitted in wall or ceiling mounted rear speakers, an idea that was quickly nixed by the lady writing the cheques.
That was just as well, because an upgrade to the room a couple of years ago resulted in not only all new colors and furniture pieces, but of course an entirely new layout. Which, BTW was completely different from what the interior design consultant had in mind.
see rant below
Unless numbers of surround / fill channels and standards regarding their individual dispersion patterns have changed, I'd be inclined to think that rotating and soffit mounting something like the floorstanding design would work just fine.
questions for Dave
LOL on the interior design tips
It's been my experience that no matter how open they profess to be to your aesthetic sensibilities and tastes, they always want to impress their "signature" on the project. That's fine, but when the reconfiguration is so drastic as to change how you can use the room, or even the shape / placement of TV screen & speakers, I tend to get a bit tight under the collar.
And then there's architects ...... "I don't care if you can't build it and get it to the room at the top of the stairs, this is the drawing the client approved, and if the subtrades built the walls/plumbing/electrical in the wrong place, you'll have to deal with it!"
Sorry, Rant Off
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As I said, I'm now looking at the mFonken for the rear surrounds. A question (in addition to that about the port aspect ratio above) is your advice on box size:
What is a good target XO freq. between the rear speaker and the sub ? I have read that popular opinion is to put it at around 80Hz. In this case, the mFonken (4.5L) goes down to 91Hz (3dB). To achieve 80Hz I need to aim for Vb=6L.
The front speakers can and will be larger so I can use them to enjoy stereo - will a big mismatch in box size between front and rear be a problem for HT ?
Lastly, how do you like the idea of a square Fonken from an easthetic standpoint (attached) ? - with the internal port structures it isn't actually square inside so no worry about resonance issues. It just happens to be a good form factor for my rear surrounds. I wonder what the interior design police would say about this !
What is a good target XO freq. between the rear speaker and the sub ? I have read that popular opinion is to put it at around 80Hz. In this case, the mFonken (4.5L) goes down to 91Hz (3dB). To achieve 80Hz I need to aim for Vb=6L.
The front speakers can and will be larger so I can use them to enjoy stereo - will a big mismatch in box size between front and rear be a problem for HT ?
Lastly, how do you like the idea of a square Fonken from an easthetic standpoint (attached) ? - with the internal port structures it isn't actually square inside so no worry about resonance issues. It just happens to be a good form factor for my rear surrounds. I wonder what the interior design police would say about this !
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Thanks Dave - I'd forgotten about the problem of those nasty square baffles!
I know the AV can provide a cut-off which helps avoid driving the little things too hard below the resonant frequency but how does this help with the concern about the box not getting me down to 80Hz unless I scale it up to 6L ???
Will be starting the work with some fresh wood at the end of the week...
I know the AV can provide a cut-off which helps avoid driving the little things too hard below the resonant frequency but how does this help with the concern about the box not getting me down to 80Hz unless I scale it up to 6L ???
Will be starting the work with some fresh wood at the end of the week...
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