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Exciting new line of fullrange drivers from Feastrex

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Feastrex

One down, one to go
 

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LS3/5a

Its a small box , the LS3/5a, So I guess if I were going to duplicate the build quality, I would need to add extra side panels and tops plus a bunch of internal bracing. The Rodgers are built like the proverbial brick sxxx house.

Then I could drill and countersink the screw holes and add a foam gasket all around.

But until we see the Feastrex numbers from Chris...this box is a good start

Darn I keep posting in the wrong place.
 
Re: One Box built one to go...

Greets!

I don't have a problem with screws per se, just the gasket material in-between the mating surfaces and why I only use at least NEMA 3R and preferably NEMA 4X rated industrial grade neoprene that should be available at your local electrical contractor's supply house and I assume on-line through McMaster-Carr or similar.

Anyway, JC broached this subject with me yesterday and there's no doubt that these driver's bulbous appendages needs some serious support/damping. Then there's the bane of all wide BW single drivers I've messed with and that's baffle and/or frame spurious resonances that normally can be delt with via one or more forms of mass loading such as massive front, rear mounting rings, HJ's adjustable screw blocks (wish I'd thought of that one!), etc..

Being a lazy sort, my choice would be to 'kill two birds with one stone' by rigidly mounting the driver only by its motor with a massive, contoured ring attached to its mounting plate to act as a harmonic balancer 'floating' above the surface of the baffle, yet lightly! compressed against a suitable gasket both around the baffle opening's perimeter and between the driver/damping ring. Now, any cab/whatever spurious resonances will be damped down at both ends.

I'd put the access panel in either the top or bottom depending on the driver's location figuring if on the bottom the structure's weight will ~guarantee a good seal and since I'm a firm believer in mass loading any cab that doesn't weigh at least as much as me, a massive top plate (slate, marble, or similar and high WAF to boot) will help with any potential sealing issues if at the top.

As always though, YMMV.

GM
 
mounting of the rear

Phil,

Agreed, don't like removable cabinet backs either. I have an idea for getting around it. However, I'm not necessarily looking to decouple from the front baffle and plan on maintaining the front mounting as well. I prefer to have a solid support mounting that does not allow any flex in the axis of cone movement. Distributing the support between the front, rear and sides makes more sense (to me at least) than providing a single support between the sides with a cross brace.

My plan is fairly simple. I'll be building a support that consists of a wooden tube that extends from the rear of the driver to the rear of the cabinet. The wooden tube is hollow and allows a longer cap bolt to be used from the rear of the enclosure and into the back of the driver. This alone gives you mounting of the driver to both front and rear. The tube itself is then braced to the sides and possibly the top and bottom (depending on the cabinet design). One could even make an "X" brace from the support tube to the corners of the enclosure internals.

Regards, KM
 
Joe, Chris,

Thanks for some good posts and information. Joe, I have to agree that as a distributor you have some fine lines which you need to adhere to and forum participation makes that a challenge. Still, thanks for joining... and as you've noted it's a smaller community of those who have these gems in-hand. Anything you can provide in information, recommendations, etc. are welcome.

Chris, as a noted close friend and champion of their products you have had some challenges on the forums. I've followed the threads on multiple forums for a long time. Thanks for hanging in there and truth be told, your passion for the drivers was a major factor in my decision to purchase a pair.

As one starter of threads around Feastrex on AudioCircles, I have tried to maintain a level playing field. I recently posted some comparison pics while unwrapping a D-5nf and a F120A (okay, the D-5nf really should come with a gasket). The images speak for themselves... granted, as noted you don't get anything beyond the driver itself but I've also noted that Kef was in a similar position back in the mid-70's offering their drivers to the DIY community, and I was part of that DIY community that used all of their DIY drivers in multiple designs. Despite limited available data the drivers achieved near-legendary status.

I'm no stranger to high-end products over the past 30+ years. The build-quality, materials, attention to detail are all first rate on the D-5nf drivers. It should also be noted that the materials chosen are very expensive compared to more common drivers. Anyone can do some minimal research and quickly find out that any driver which employs an Alnico magnet in the motor has a very high cost. An accurate comparison is the Fostex FX120 and F120A... almost the same driver sans the magnet assembly. The price difference? ~$103 for the FX120 and ~$229 for the F120A. Pretty wide gap to move to Alnico! Reason? Most Cobalt exists behind the old iron curtain... hence it's price is very high... and nickel is also pretty high cost these days. In short, I'm not put off by the pricing of the D-5nf driver. I do have some high expectations which will be found out soon.

I also look forward to any additional measurement data and would like more detail on how Feastrex match up their pairs at the factory. If someone has some published specifications on the enclosures the factory uses, that would be a nice baseline for the DIY group. I'm also tempted to get the Woofer Tester/2 to obtain some of my own measurements on the pair I have (and the Fostex units too).

Regards, KM
 
Re: One Box built one to go...

Phil Townsend said:


I know you have to get at the Feastrex to screw it to the internal brace....

A better way...please?
Ideas...anyone.

Hi Phil,

How about this idea... first using a wooden rod ( cut to the correct length) fasten to back of the D5nf,... then mount the driver into the cabinets, put a rubber like material so that the other end of the rod, so that it will press against the back panel of the spk box.

Not quite that rigid but simplifies the mounting problems..
 
kmaier said:
An accurate comparison is the Fostex FX120 and F120A... almost the same driver sans the magnet assembly. The price difference? ~$103 for the FX120 and ~$229 for the F120A. Pretty wide gap to move to Alnico! Reason? Most Cobalt exists behind the old iron curtain... hence it's price is very high... and nickel is also pretty high cost these days. In short, I'm not put off by the pricing of the D-5nf driver. I do have some high expectations which will be found out soon.

Regards, KM


If you like the F120A driver, the D5nf will surprised you with what it can do.. in terms of tone, bass, SPL.. It really doen't sound like a 5" driver at all... But do give the drivers 200 hrs for it to really run in ... The bass and ability to go loud will improve greatly. Look forward to your impressions.
 
New Maiko cabinet for the Feastrex D5nf

I wanted to let people in this thread know that I just started a new thread called "New Maiko cabinet for the Feastrex D5nf" to announce a new cabinet that Scott and Dave of Frugal Horn designed specifically for the Feastrex D5nf driver.

All the details are over there in the new thread, but I'll post the preliminary rendering of the cabinet below for your reference.

This is great news for people who have this wonderful driver!

Mike Luckow
 

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D5nf Height

I had the distinct feeling that the D5nf, at the very least, in the cabinet with the PB9 passive radiator was too low as it was displayed at RMAF. As shown in the photo below, it has been raised an additional 5" by the insertion of lead shot filled plastic boxes between the bass and the enclosure itself. The height to the center of the phase plug from the carpet prior to the insertion of the boxes was 33 1/4" (the same arrangement we had at RMAF). In the photo it is 38 1/4". If I measure to ear height approximately while seated in my couch it is in fact around 39" if I'm sitting upright. In the elevated position, everything is better: air, imaging, fine resolution, depth, height - even the bass is improved, though a case could be made for the lead filled boxes having something to do with that. I would caution those designing enclosures to experiment with height, and to try and achieve this height if at all possible. At the lower height everything feels more compressed and effort-ful.

An externally hosted image should be here but it was not working when we last tested it.


This is a remarkable speaker. The bass does extend lower than it has a right to, and though it doesn't provide full and deep bass, what is there is quite satisfying.

Joe Cohen
The Lotus Group
 
Phase plug change?

Joe,

Interesting to notice that the D5nf shown appears to have a brass phase plug instead of the plastic ones that seem to be standard (like mine). Is this something you did on your own or has the factory made a change? Also, does it make a noticeable difference?

Regards, KM
 
Re: D5nf Height

talawalla said:
The height to the center of the phase plug from the carpet prior to the insertion of the boxes was 33 1/4" (the same arrangement we had at RMAF). In the photo it is 38 1/4". If I measure to ear height approximately while seated in my couch it is in fact around 39" if I'm sitting upright. In the elevated position, everything is better: air, imaging, fine resolution, depth, height - even the bass is improved, though a case could be made for the lead filled boxes having something to do with that. I would caution those designing enclosures to experiment with height, and to try and achieve this height if at all possible. At the lower height everything feels more compressed and effort-ful.


Hi Joe,

Thanks for the feedback, I just collected my new cabinets for the D5nf and the PB9s.. The carpenter sure took a long time .. and yes I did basically follow Feastrex 's box design but I asked the carpenter to build in an enclosed spk stand so my boxes look like a tall floor stander. Interestingly, I too arrived at the phase plug 38" from floor level to be a good figure. Will post some photos when the drivers get mounted.. still have to attach the braces and drill holes for the binding post etc.. :)
 
D5nf -Gold

Hi Kevin,

The D5nf- Gold comes with a phosphor bronze phase plug. I've not had a chance to A-B too many phase plugs. At the show Mr. Teramoto brought some that were Urushi lacquered black and some that were clear lacquered Japanese Aomori Hiba - Cedar. They did have different properties. I think we liked the clear finished cedar ones that Mike Luckow has the best. I can find out about the cost of replacement phase plugs. I do know that Mr. Teramoto employed the services of a National Treasure Lacquer artist to finish the plugs so the price will be fairly dear.

Joe Cohen
The Lotus Group
 
Amen / Oy!

The Dollar is slipping against the Yen. Though I have no intention of raising Feastrex prices, if the dollar slides near or below parity with 100 yen to the dollar the ballgame shifts, and we are getting perilously close. Today the dollar will fetch 108.6 yen. That, of course is the official rate, one never gets this rate when purchasing yen. So the actual rate may be around 107 or lower.

Oy!

Joe Cohen
The Lotus Group
 
nice....

So...

Phil, tell me how you really feel! Are you using the Spawn enclosure like Rich? I'm putting together a pair in red oak shortly to get them up and running quick. My TL prototype will be a little while, just not enough free hours.

Chris, thanks again for the quick clarification and info... forgot about the Gold ones... still elated with the build quality and attention to detail on my cheap black ones! Also, which enclosure are you using?

Joe, Sounds like some customization capability... should be able to do interesting pieces with a CNC lathe. Is there a general "feel" for different materials used in phase plugs? Also, are the Feastrex enclosure designs available?

Well, I'm getting antsy to get mine running.... and about to test my 300B prototype amplifier which will ultimately drive them... Feastrex meets Westrex.

Regards, KM
 
Enclosures / Plugs

Kevin,

So far it seems we are all looking for an ideal enclosure. There is certainly promise here with the Maiko and Fat Freddie and Freddie Chang. I'm sure there will be others to come along that will also be most desirable. I think it is probably early days yet for Feastrex to decide which enclosures they think will yield the best results. When they do, I have every confidence that Mr. Teramoto will want to make plans available.

Regarding phase plug material. I think that each one has its own character. I liked the cedar plugs because they sounded very smooth.

Joe Cohen
The Lotus Group
 
frugal-phile™
Joined 2001
Paid Member
Re: D5nf Height

talawalla said:
The height to the center of the phase plug from the carpet prior to the insertion of the boxes was 33 1/4" (the same arrangement we had at RMAF). In the photo it is 38 1/4". If I measure to ear height approximately while seated in my couch it is in fact around 39" if I'm sitting upright.

Evry person needs to adjust height based on where their ears are when listening. My ear height when seated is ~33".

dave
 
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