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Chang box plan for Feastrex D5nf

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Hey Richidoo any more plans or details for TLs or BLHs for the Feastrex drivers? The picture you posted has a note that says mounting details to follow. I've started collecting wood for this project. It's still a ways away but I hope to use FEASTREX D5nf drivers. It will be beautiful with exotic wood (different wood from my Fostex project if you read that post) and textured black.
 
Thanks Clark,

It's my plan to sell off a lot of speakers I've built and am building to afford the Feastrex. My problem with the FR community as whole is that everyone seems to be a proponent of thin walled resonant boxes. I'm the opposite. I build boxes with 3/4 to 1 inch sides and 1 1/2 inch front baffles. Some times thicker. I don' like cabinet resonance as a rule. And the thicker pieces are easier for me rabbet join. Some of the cabinets I've seen for the Feastrex LOOK like they could be heavy. But I can't really tell by the appearance of the final product. Now when I build cabinets for the Feastrex I plan to use some solid wood (some really nice stuff!) that I've purchsed for the outside on the sides and top of the cabinet. I will try to keep the side thickness to a minimum but it will probably still be an inch or a little more. If the Feastrex drivers don't perform well in a heavy cabinet, I might have to rethink this project. Maybe FR isn't for me. I've bought the Fostex FE163En-S drivers and will be building cabinets for them. Probably the Fostex recommended BLH.

BTW-Love your website and looking forward to your Feastrex projects!
 
Thanks Gary, and I couldn't agree more with you about wall resonances. When you get to an enclosure as large as a 50-60 liter Feastrex 5" enclosure, 3/4 inch or 3/4 inch braced is a good idea. A doubled front baffle doesn't hurt either.

A big factor here is that the smaller the size of your cabinet walls, the thinner they can be and still be very stiff, non resonant, and strong.

My rule of thumb is to let the walls resonate "just enough" - neither totally dead, nor (definitely) not boomy and ringey. The amount of box life is directly related to the amount of "life" to the paper cone/inherent distortion of the driver itself. So really, its somewhat of an aesthetic balancing act to get good sound out of an enclosure. Trial and error helps tons towards this - building enclosures out of different thicknesses and weighing the benefits/compromises of the "body" given to the sound as a result. Truly, this can't be computer modeled with any reliability, and only scantly measured.

The FE163EN-S is a nice driver. Lots of bass and a pretty even upper band considering the size. It still does not compare to the Feastrexes though, especially in terms of high frequency dispersion. My pair of FE166ES-R's were so similar sounding to my 163EN-S that I sold the EN-S's

Your project sounds like it is going to be REALLY awesome! Can we get some wood porn?

-Clark
 
Feastrex spks really do sound very good in thick and rigid cabinets... The latest cabinet we made is a bamboo and plywood hybrid cabinet of 33mm thick wall thickness... see the video clip below :

Feastrex NF5-EX PIP + Full Kondo Setup - YouTube


Thanks Clark,

It's my plan to sell off a lot of speakers I've built and am building to afford the Feastrex. My problem with the FR community as whole is that everyone seems to be a proponent of thin walled resonant boxes. I'm the opposite.
 
My problem with the FR community as whole is that everyone seems to be a proponent of thin walled resonant boxes. I'm the opposite.

Completely untrue. The vast majority (probably more than 99%) of people who design or use wideband drive units are not enamoured of, let alone proponents of, 'thin walled resonant boxes'. You may be mistaking boxes designed with high stiffness - weight panels, heavily braced to shunt panel resonance up, above the operating BW of the box, for enclosures intended to produce audible panel resonances, i.e. the exact opposite.
 
Sorry

Completely untrue. The vast majority (probably more than 99%) of people who design or use wideband drive units are not enamoured of, let alone proponents of, 'thin walled resonant boxes'. You may be mistaking boxes designed with high stiffness - weight panels, heavily braced to shunt panel resonance up, above the operating BW of the box, for enclosures intended to produce audible panel resonances, i.e. the exact opposite.

Hi Scottmoose,

I'm glad to hear that my perception is untrue. However, it is not untrue that it was my perception. Admittedly I haven't visted very many of the threads or joined in many discussions here yet. But it did seem that a lot of people preferred 12mm (1/2 inch?) sidewalls to their cabinets and that people were critical of some of the Fostex recommended designs because they were "heavy built". Sorry if I ruffled anyones feathers. Also I may be guilty of always building heavier when in doubt. I've been building speakers for about 10 years but all of my experience is outside the FR, BLH and Tl areas. Most of the drivers I've used have been Vifa, Scan Speak, Seas or Peerless. And every time it seemed that the lower resonant cabinet sounded better. I am going to try to build these FR designs closer to the original design than I might have done previously, especially in cases where it was what was best for the driver and not because of economy.;)
 
Feastrex spks really do sound very good in thick and rigid cabinets... The latest cabinet we made is a bamboo and plywood hybrid cabinet of 33mm thick wall thickness... see the video clip below :

Feastrex NF5-EX PIP + Full Kondo Setup - YouTube

William, this is a gorgeous system! And what camera work too! I know myself from many nights listening to my NF5ex that they really do visually start "falling away" ever so slightly like at 4:04 in teh video.

I'd love to hear a set of your cabinets, and the thoroughness with which you've built them gives much inspiration to me in my future builds.

Cheers!

-Clark
 
I'm glad to hear that my perception is untrue. However, it is not untrue that it was my perception. Admittedly I haven't visted very many of the threads or joined in many discussions here yet. But it did seem that a lot of people preferred 12mm (1/2 inch?) sidewalls to their cabinets and that people were critical of some of the Fostex recommended designs because they were "heavy built".

Really? 1/2in panels are moderately common for small standmounts or desktop speakers, since, when well braced, with small wideband units they do the job fine. Larger speakers? Not many quality examples of those with 1/2in construction. For small floorstanders, 15mm is about the lowest I've seen most people here go, and 18mm - 3/4in is the typical minimum. There has in recent weeks been another upsurge in interest for (relatively) thin-wall construction with heavy bracing & extensive bitumen damping popularised by the BBC for small boxes -what once was old is again new. If you examine the BBC's research paper though, you'll quickly appreciate that this is merely an alternative method to killing panel resonance.

Fostex's designs do often get some criticism, but this is rarely because they're thought to be 'heavily built' and rather more because some of them are simply not very good. Not all, but some. Their horn designs are sometimes also disliked for the high parts count, although since most only have 90 degree angles, they're quite straightforward builds.

Also I may be guilty of always building heavier when in doubt. I've been building speakers for about 10 years but all of my experience is outside the FR, BLH and Tl areas. Most of the drivers I've used have been Vifa, Scan Speak, Seas or Peerless. And every time it seemed that the lower resonant cabinet sounded better. I am going to try to build these FR designs closer to the original design than I might have done previously, especially in cases where it was what was best for the driver and not because of economy.;)

I don't think you quite understood what I said. A cabinet designed with high stiffness - weight / MOE panels should not have audible panel resonances. The object behind using very stiff (often relatively low-mass), highly braced panels is to raise the Fs of the panel well above the operating BW of the enclosure, to a region where there is very little energy available to excite it. Any minor resonances left can then be easily handled with very small amounts of damping (since amplitude and the resonant BW of the panel has also decreased). For small boxes, as Clark mentioned, this can be achieved with fairly modest panel thicknesses -larger enclosures need stiffer panels of course, and that usually means thickness has to go up -how much depending on the build material and bracing. A box with audible panel resonances is either insufficiently stiff and / or insufficiently damped.

Much of this goes hand in hand with the popular dislike of MDF, which is relatively high-mass, and not very stiff: for e.g., based on average MOE values, you'd need ~ 1 1/8in of MDF to equal the stiffness of 3/4in of BB ply, and that of course comes as mentioned at the price of considerably higher mass. In truth, you can get good results from it, but it usually takes some work.
 
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dust, dust and more dust!

Yes Scott. I constantly wear a respirator and I am cleaning almost every day. Including days when I do no work on my speakers. I'm hoping this year to get all my projects finished. I then plan to disassemble my shop and completely clean everything. then set up a new shop with a very good vacuum sytem and separate cutting/sanding and finishing areas.:D
 
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