Sumiyama's DIY page
SUMIYAMA's DIY page
East Rock Park (New Haven,CT)
Last update: 6/21/2004
new mail address
testing MCM aluminum concave 6.5" woofer
MCM subwoofer & Partsexpress sub amp
RP tweeter & Vifa P17WJ
RP tweeter (may be made by Foster electric, some time around 1985) is mated with P17WJ by second firstname.lastname@example.orgHz
test model -- simple pipe TLS
An experimental design, using two 8ohm MCM 55-2205 in straight pipe. Awesome, mighty bass!!
floor standing 3way - freq. response
Using two 4ohm cone mids in series, to eliminate attenuation from tweeter circuit. It has a sidefiring subwoofer. Clean, smooth midrange and dynamic bass.
kevlar tls (freq. response)
This is an experimental transmission line design, using MCM 6.5" kevlar midbass (looks similar to Focal 7K2) and Audax DTI-01 with a bucking magnet (it really improves sound quality), crossed at 4kHz, 12dB/oct. TL length is just 1.5m and fully stuffed with poly-fil. Because of high Fs of midbass driver (110Hz), low extention is not great. It will be combined with active subwoofer. TL is just used to reduce unwanted resonance and pressure in back chamber. Actually this TL cabinet put better sound than 20L closed box. The midbass driver has a bit colored midrange, but not "harsh" at all. High efficiency (94dB/W/m).
===temporary=== plan for cabinet and network (simplified plan with parts list) in pdf file
Text for TLS design : effect of polarity of mid-high driver on frequency response
An example that cheap but great sounding drivers can make an affordable full-range system. Transmission line design can put 28Hz as same amplitude as midrange. A quasi-linesource design significantly contributes to good horizontal dispersion, soundstage, and scale. Two dome mids are connected in series, to surpress distortion caused by excess voice coil movement (a weakness of dome drivers), increase resistance in order to use parallel resistor to kill Fs impedance bump, and adjust mid level as same as that of tweeter to eliminate series resistor from tweeter circuit. Simply great sounding system for bucks (around $500/pair). My recommendation for DIY beginner.
A simple 2way design using great small vifa 5 inch midbass as full range driver. Tweeter is added with minimum crossover. Probably best small 2way I ever made.
My current main system. Double chambered ported design (now I am using them as damped vented box though...). No need to mention about the quality of those Scan-speak drivers.
Also an experimental design, to eliminate series inductor for woofers, by using them in slanted angle. Vifa P13 with smooth mid-high response makes it possible. No attenuation for tweeter.
An radical experimental design, using a stage monitor fullrange on extremely slanted baffle to divert beaming & screaming highs, and a protrusively located tweeter in "quasi-time-coherent" position.
Superb sound, other than screaming peak around 8KHz. Great bass response down to 50Hz. It was dampened by 40kg blocks and reinforced with steel bars and angles.
Please let me know your
impression or send your question to: b.j.@fish.co.jp