Small group and acoustic music sounds wonderful. Of course the bass doesn't blow you away, but 50 Hz is there and it fills my room with music. The TQWT enclosure gets good low end from this little driver. The Fostex FX120 speaker driver is well balanced, with a relaxed sound, detailed midrange and good highs (also very well assembled). Photograph 5: Fostex FX120 Transmission Line SpeakersĬonclusion - Fostex FX120 ML-TQWT Speaker Project The enclosures finish consisted of sanding 60, then 120 and then 180 grit sandpaper and four treatments "hard wax oil" that fires up the color of the wood and protects the surface. The two panels out of aluminum on the front and top are anodized in black and covered with a shiny clear coat. Photograph 4: Fostex FX120 ML-TQWT Speaker Box Internalįor the base-plate I found a granite plate at a stonecutter's store, he made them for a moderate price for me. The cavity in the cabinet was filled with gravel to add some mass to the enclosure and prevent resonance. Photograph 3: Fostex FX120 ML-TQWT Baffle Step Compensation Circuit I don’t know if it helps, I thought it couldn’t be bad doing this. Also, I placed some felt behind the driver and at the end of the line to avoid reflections. The wiring must be in place and the hole in the back for connecting the wire with the BSC has to be sealed. Another thing is to put in the damping between the inner and back plate as you cannot do this through the driver cut-out once the cabinet is closed. First I attached nylon strings between the sides to keep the damping material from falling to the bottom. Photograph 2: Fostex FX120 Baffle Chamferīefore I closed the box with front and top there were four things to do. Photograph 1: Fostex FX120 ML-TQWT Enclosure Construction Naturally you can use material of a different thickness, but be sure to adjust the dimensions in the plan. The enclosures were made using 15 mm birch-multiplex, the front baffle and the top is 19 mm beech, and the inner plates are 16 mm MDF. Fostex FX120 ML-TQWT Cutting Plan - (PNG 191kB)Įnclosure Construction - Fostex FX120 MLTL.Fostex FX120 ML-TQWT Enclosure Plan - (PNG 151kB).Fostex FX120 ML-TQWT Building Plan - (PDF 70kB).The BSC is necessary, otherwise the sound isn't balanced.įigure 3: Fostex FX120 ML-TQWT Baffle Step Compensation Circuit Fostex FX120 ML-TQWT Enclosure, Cutting and Building Plans I played with the length of the port and tested several values of inductors and resistors for the baffle step correction (BSC) circuit. I began to tune them by ear until I was satisfied with the music coming out of the speakers. Figure 1 shows the calculated frequency response for the FX120 for the enclosure shown in Figure 2.įigure 1: Calculated Frequency Response - Fostex FX120 ML-TQWT (T-Line)įigure 2: Enclosure Plan - Fostex FX120 ML-TQWT (Transmission Line)Īt first they were a little bit harsh but after about 100 hours they smoothed out. King for his kind help and advice) I made some test enclosures out of chipboard. With his feedback "I think you have a design" (I want to thank Mr. King and asked him to have a look at the simulation I had completed.
With the Mathcad worksheets I designed a Mass Loaded - Tapered Quarter Wavelength Tube (ML-TQWT). The goal was to let them go down to about 50 Hz. The FX120 will need a little help on the bottom end. On the Fostex data sheet they show a flat frequency response without great peaks and drops.Įnclosure Design - Fostex FX120 T-Line Project There is not much information available for this driver, but the feedback from people who have used was positive. Searching a smaller driver the Fostex FX120, a 12 cm fullrange unit caught my eye. My first try was a speaker using the Fostex FE167E, but I never made proper cabinets for them because my wife said "No way, they are too big". King and decided to try a speaker design of my own. Looking for more information about fullrange drivers, I found the Mathcad worksheets by M.J.
FULL RANGE DRIVER SINGLE TQWT DIY CHRISTMAS DRIVERS
However, there are compromises with fullrange drivers little drivers have disadvantages at the low end and bigger ones at the top end. Fullrange drivers seem to play music with more coherence, more life and they sound more direct. I decided to give them a try and was surprised with the sound quality! Of course they did not play as loud as the bigger two-way speakers that I built before, but something else was fascinating. My first introduction to fullrange speakers was about 4 years ago in a German diy audio magazine which featured a small transmission line speaker project using a Vifa 10 BGS 119/8 driver. Introduction - Fostex FX120 MLTL Speaker Project
0 kommentar(er)
