"Limes" : A Voight Pipe using FE 83


  

"Limes" started like a joke, just to spend the time during one of those misty and grey weekend.
The need was to have a nice-lookin' and enoughly small cabinet  for  the living room, to listen to television  with your family without renouncing to a good overall quality.
Of  course low cost was a must.

We started the serach of a project  last october in our collection of speaker-buildn' rewiews  and in the web.
After a few day a lot of projects were eligible but.... none passed the ultimate test: our viwes. ;)

We've to wait till december when finally in the italian rewiew "SUONO" was published what we were looking for:
a very cool looking cabinet with a thin profile to save space, using the very cheap Fostex FE83 speaker.

For the complete article plese refer to the original issue:

Article Title: "Limes"
Author: Giuliano Nicoletti ( gnicoletti@tiscalinet.it )
Published in november 1999 issue of the Italian HI-FI review "SUONO".
In the review there is also a facility for people who are far from big hi-fi shops: for 384.000 lire (about 190USD). are available: the detailed plan of costruction, the two FE83 all the material for costruction (helmothz resonators etc.) wood not included.
 
Abstract of the article are available in a couple of place in the web: you can click here while holding the shift key pressed to retreive the diagram of the cabinet, with the main dimensions.

 

Photo Gallery & Tips of Costruction :
 
From our experience costruction is not so easy, but still at hand of a medium skilled DIYer.
The main problems we found was in  the triangular shape and in the uncommon tallness that obliged us:

We all  used 20mm plywood. Is better not to use  less expensive MDF.
 
 

Great care must be taken with :

I've obtained good result using that loose fluff that is used in kitchens for adsorbing smoke in the fans above the fire place.  You need only a little sheet to cover the rear wall behind the FE83.

Here is a photo of the internal helmothz resonators. The tubes can be found in every supplier of parts for building houses (bricks, tubes etc..). They were supplied me for free by a bricklayer who lives in my neighbourhood. The tubes must be filled with loose fluff accordin to best bass response.

 

Note that to strenghten the joint with the openable wall of the cabinet a special slot with eliptichal wood joints  is used. This slot permits correct positioning of the removable wall.
To avoid air loss, the removable wall is sealed using silicon rubber for motor gasket. the silicon rubber is the thin black line.
 

A close shot of Fostex's FE83.
 
 
 

 
 
 Placed near our "reference speaker" "Side Vivace".   
 
 

Note the spacers below the pipe. The thickness of the spacers have been choosen after several attempt for best bass response according  to the positioning of the speaker in the room.

We've choosen 2cm thickness, after experimenting with different wooden blocks heights starting from 1cm to 4cm step of 1cm.
Lower distances give more basses but also cause the sound to be a little "slow" and compressed, with more evidence of "holes"  in the spectrum.
Higher distances reduces the bass reinforncements. 

In Place  and ready to fire!!!!
 

 

In the backgroundour reference amplifiers:  "Il triodino III" using 2a3 & 6sn7GT tubes, built in one separate chassis for each channel.

In the foreground, on the white table the Triodino III first version, using 300B instead of 2a3 build on a single chassis.
 
 
 

Listening Impressions 
 
What we asked to  this speaker was good reproduction of voices and -if possibly- a good overall sound.
We thought of course that using the FE83 meant clearly to renounce to almost completely to Bass and to high power level.

We were wrong, at least in the first guess.
When we first connected the Limes  to our reference amplifier (our modified version of "il Triodino III") we were all surprised: we heard one of the best highs and - surprise - also a nice bass extension was present.
All this only with 3W power!!! and 89db efficiency.
Of course there wasn't the impact and dinamics of bigger cabinets, but the voice was very  trustful and present, bass was a little "behind" but with surprising extension.  Infact reading the article we discoverd that this little monster can reach 48Hz (-3db).
In a few world a very good result for the FE83: a 6cm speaker (!).

We suffered  the appreciation of our viwes: the  "limes" in the living-room has become "a must" so we all had to own  a couple (8 spekers in total!).  :))))))

 We've Just  enjoyed  "SANREMO" with this nice speaker.
 

Back to my  homepage