FE127 project

[edjosh23]

I finally got one of my friends into this whole DIY thing. He was on a very tight budget so I recommended the FE127. He recieved them last night from Madisound, and today he brought them over, we listened to them for a little bit and he is leaving them here to break in. Tomorrow we are going to build some cheap boxes to go next to his computer monitor. They aren't going to be very great for bass and due to such a tight squeeze in his computer desk, they are going to be a little small and slender. What we have decided is to build a .5ft^3 box ported and tuned to 66hz. For the next couple months he will live with that until we build a back horn or TQWT. I've done quite a bit of searching, but I'm still looking for more designs. A horn would be great, I've never built one and am very interested in them.

I've heard lots of things about how long these things need to break in and right now it is really obvious they need to be broken in, they are really really harsh. The packaging was great and the build quality of the drivers are really nice. These are so different from the drivers I'm used to seeing.

I'm really looking forward to listening to these and building boxes for them, I only wish I could speed up break in.

Any enclosure suggestions?

Thanks,

Josh

 

[Dumbass]

A vented transmission line, designed specifically for the FE127E by GM:

>>>L = 22.38"
>>>W = 7.43"
>>>D = 4.58"
>>>driver down 8.85" from top
>>>1.5" dia vent x 1.125" long near/at the bottom
>>>Just a couple of oz of stuffing behind the driver

You can even use a 2" port, and get a little 2dB hump in the bass.

If you want to be really cool, put the thing on legs (at least 2" long) and have the port down-firing.

But don't take my (or GM's) word for it; build it cheap & dirty from some particle board (just ensure air-tightness) and see how you like it.

 

[edjosh23]

Thanks,
My friend is still trying to figure out the space, and it might not end up being good to try and squeeze the speakers on the two sides of the monitor because space seems to be very limited.
We decided that we are going to build some boxes to matter what, so that could be possible for this weekend.

How would I calculate that port size into a rectangular vent?

Do you happen do know any BLH for the fe127?

Thanks,

Josh

 

[MPM]

http://www.diyaudio.com/forums/attachment.php?postid=526880&stamp=1102221644&

OR

http://www.diyaudio.com/forums/attachment.php?s=&postid=528487&stamp=1102449671&


Most the the thread below pertains to the fe127.

http://www.diyaudio.com/forums/showthread.php?threadid=46934&perpage=10&highlight=&pagenumber=1

 

[moray james]

Look at this

http://www.yildiz.edu.tr/~ilkorur/speaker/fostex_fe127e.htm
I don't imagine that you will find the equal much less better this design. Regards Moray James.

 

[edjosh23]

Well I convinced my friend to go with GM's plans.

I put everything into winISD and the port size is the same as Gm's box. I've decided to go with a a rectangulr vent out the bottom of the front baffle. I've calculated the vent to be 7.43"w x .5" and 2.22"long

Does that sound about right?

Well I'm waiting for him to get wood and some stiff from radioshack, it looks like we might not get much work done since it is already almost 5pm, but hopefully we can build everything pretty quickly.

and thanks for the links

Josh

 

[GM]

Greets!

The vent needs to be acoustically ~2.82" long to tune it the same, so if you're using the side walls/bottom to form three of its sides, then in theory ~2.22" is close enough, but the aspect ratio is considerably >9:1 so it may be resistive enough to tune it lower than predicted.

GM

 

[jim_vt]

I'm thinking about building one of these as well...however I'm confused on a few things.

How much stuffing is required, and how do I go about securing it inside the cabinet?

Are those internal dimensions, or external ones? And if external, what size stock was used...

Thanks for the help

 

[GM]

Greets!

All dims are inside. Stuffing is a personal thing. Lon swears that any kills off too much of its dynamics, but I feel a small amount behind the driver is sufficient, while some others prefer to line the walls/top down to below the driver or suspend an acoustic 'drape' of 1" thick acoustic fiberglass insulation from the top.

Loose stuffing can be held in place by stapling or gluing webbing across the cab at the point where you want it to stop. Another is to make a bag out of cheesecloth or expanded mesh that can be attached to a wall or suspended from the top.

GM

 

[jim_vt]

Could you maybe draw a picture of what you mean? I'm having a brain fart...usually happens around this time of night.

Thanks for the assistance so far though

 

[Dumbass]

Could you maybe draw a picture of what you mean? I'm having a brain fart...usually happens around this time of night.

Thanks for the assistance so far though

Well, the idea is that in a TL you want the stuffing to be on the driver end of the pipe, down to about half the length of it. Since stuffing drops with gravity, you need to figure out a way to suspend it so it doesn't settle at the bottom.

 

[jim_vt]

It just seems so....inexact

I guess I'll buy a bag or two of polyfill and some netting and play around.

 

[youyoung21147]

IMHO if you use a bag it means you need much stuffing. Maybe it isn't necessary.

Personally I use some polyester fiber that is presented like a thick and lite "carpet". You cut it to the dimensions you need to fit your cabinet, and just fix it on the walls with tape, it works very well and there is no risk to see the stuffing whistle or fall in the enclosure.

it looks like this : http://www.conrad.fr/webapp/wcs/sto...rent_category_rn=19639&ItemHighLightId=209868


You can also look at my projects on my website, there are photos of what I mean


Just my 0.02$

 

[GM]

IMHO if you use a bag it means you need much stuffing. Maybe it isn't necessary.

Personally I use some polyester fiber that is presented like a thick and lite "carpet".

Greets!

Right, if someone feels the need for this much stuffing in such a small cab for it to sound good, then the cab is either way too small for the driver or tuned wrong, which we know isn't the case with this design.

Yes, this material works fine at 0.5 - 0.75" thickness in a typical size cab and 1.0 - 2.0" in large cabs (> ~3 ft^3)

GM

 

[edjosh23]

Well yesterday we got a suprizing amount of work done. He and I discussed finishes and he decided he wanted to buy some inexpensive yet pretty plywood. So he got here at about 6pm and we started working, cutting all the wood and gluing many pieces. We decided to build it similar to the way Vikash built his w3 871s. If you don't remember the way they look the pannels are all glues together (with ofcourse butt joints) so that the front baffle fits into the sides and the top. This way you can see the layers in the plywood. We have done everything but the sides.

Unfortunately We already made the vent 2.22". I guess we will add quite a bit of stuffing. I also think that we are going to add a small brace a couple inches bellow the driver. I'm listening to them right now with no sides, not the best way to listen, but I've got a lot of work to do right now so I can't finish them right now.

The speakers still need to brake in more, they have become a little less harsh and the detail has come out some. The bass is not bad, but not as good as the wr125s.

Any recommendations for making the port longer without having to take off pieces?

I tried to take some pictures buy my camera is not working properly, wants new batterys when I put new batteries in there.

I'll post more info later when more work is done and when I can get some pictures.

Thanks,

Josh

 

[youyoung21147]

if it is a circular port, use a tube made out of cardboard, or thick paper. Insert it in the port and make its length vary by moving the cardboard tube inside it. It will be at least sufficient to find the best tuning.

 

[planet10]

The bass is not bad, but not as good as the wr125s.

It never will be... it should edge out the WR in the mids thou & requires a 1/4 the ampifier power (speaker design is all about trade-offs)

dave

 

[youyoung21147]

I'd be very interested to compare th FR125 to the Fe127 and FX120.

I bet the FR125 has more bass than Fe127, but I also think it cannot have the detail level of the Fostex drivers. It's a matter of taste then !

 

[edjosh23]

Well I've finished the construction of the speakers. I'm very jealous! In the boxes the bass is very good, still not as good as the WR125s, but I think the detail is here. I haven't listened to many cds yet, right now I'm listening to "Take Five" by Dave Brubeck. I've listened to some John Mayer, some Dave Matthews band. I'm gonna slip in some Phil Collins, Joshua Redman, John Legend and others. I have not done a comparison with the wr125s, I really don't have to time right now, I am suprized I got this much work done today. I'll try and take pictures again after some more listening.

Thanks,

Josh

 

[edjosh23]

Well Ive listened to quite a few more cd and I really like these speakers a lot. I moved them up on my computer desk, how my friend is going to have them and they are pretty big. Well I was able to squeeze one picture out of my camera before it died on me.

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

Josh