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Tobler-ONE: Jordan JX92S T-Line Speaker

Francesco Campedelli    Italian Flag     To email Francesco, type out the email address.

Page 1: Introduction, Enclosure, Design
Page 2: Construction, Photographs, Costs, Impressions


CONSTRUCTION

The enclosure has been constructed using 15mm thick beech plywood. Why beech? No mysterious special sonic quality here, just that the hardwood floor is beech. The wood has been cut at a lumber yard, since I could not cut the 60 degree angles with my humble tools. The pieces have been glued together using only vinilic glue. After gluing, the enclosures have been finished with synthetic nitro primer. I've used two medium-quality gold plated connectors for the speaker connection and internal wiring is simple CAT5 LAN cable. PVC pipe (60 mm diameter) is used for the port. After completing the speakers, their shape suggested the name: Tobler-ONE (I'm sure you are fammiliar with the famous Swiss chocolate ;-) ).


TOBLER-ONE PHOTOGRAPHS

Unfortunately, photos are only available after construction was completed.

Jordan JX92S Transmission Line Speaker
Photograph 01: Tobler-ONE Speaker - Front, Side and Rear View

Jordan JX92S DIY T-Line Speaker
Photograph 02: Tobler-ONE Speaker - JX92S Driver and inspiration for the name

Tobler-One Speaker in the room
Photograph 03: Tobler-ONE Speaker in the room


PROJECTS COSTS

  • Jordan JX92S: 360 Euro VAT included (but I got a good rebate)
  • Beech wood, complete with cuts: 220 Euro (VAT included)
  • Dacron Polyester Fiber: 5 Euro
  • Terminal Connectors: 13 Euro
  • Synthetic varnish (0.5 L): 7 Euro

Total Costs: slightly above the budget


LISTENING IMPRESSIONS

The listening test was performed in the living room (dimensions 4.5 x 7 m), using two different DIY amplifiers: a 20W gainclone and a 10W Class-T (web pages are in Italian). The loudspeakers are placed in the corners of the short wall, with the driver centers at 4 m (listening position is on axis about 3.5 to 5m away).

These Speakers have only two critical points:

  • The Jordan drivers are at their best (but what a best!) when played at medium to high SPL. At low to very low SPL, the HF response seems slightly "veiled".
  • Similar to other full-range speakers, the Jordan JX92S drivers are quite directional. The optimal listening area is on axis or not more than 15 to 20 degrees off-axis. Outside that range, the HF response drops off.

The good points:

When corner-placed, listening is optimal at medium SPL. Increasing SPL may lead to an excessive level of LF. Depending on your prefered listening level Dacron filling in the port can be used to adjust the sound to your tastes.

When the loudspeakers are moved at least 70 to 80 cm from the side walls (but still near the back wall), the frequency response is "flatter" and more equilibrated, with a very pleasant and realistic sound reproduction.

In detail, the reproduced sound is timbrically very correct, much more than the sound from the Fostex 206 Bass Reflex (which sometimes seems a little "harsh", especially with classical music). The capacity to recreate the soundstage to identify single instruments is very good, especially with live rock and jazz.

In closing, this is the best loudspeaker I've built (at least up until now), both sonically and aesthetically. The Jordan JX92S driver costs are not low, but they are well worth their price considering the amazing sound quality. With no colorations, these drivers let you to listen to music and to forget their presence ...


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