Supravox T215 RTF 64
The abbreviation RTF in the name of this driver comes from la Radio Télévision Française. Supravox created this drive in mid sixties with revolutionary for its time membrane to fulfill the requirements of French studios like ORTF, RAI, RTL and EUROPE 1. Very soon T215 RTF 64 became one of the most popular fullrange drivers among the audiophiles.
The cone is made of long-fiber paper, with impregnated
center sector for more rigidity. The surround
is three-ribs "accordion" type without coating.
The whizzer cone is very thin and very stiff to a touch. From
the picture can be seen that it is attached at the inner surface
of the voice coil. The dust cap is common part of
the whizzer.
The gasket is made of 6 mm thick fine white felt.
The magnet system features AlNiCo
(Ticonal) magnet which is covered with
aluminum back cap.
On the die-casted aluminum alloy we can see a base for a matching transformer in case the loudspeaker is used in a 100 V line network. Because of this supplement the driver can be mounted at the back of the acoustic panels only.
This is the manufacturer's brochure
My Measurements
| Driver Properties | Thiele - Small Parameters | ||||
|---|---|---|---|---|---|
| Chassis material | Aluminum Die Cast | Parameter | Measured | Datasheet | |
| Membrane material | Paper | Fs | 55.5 Hz | 50 Hz | |
| Magnet System | AlNiCo | Re | 5.9 Ω | N/A | |
| Surround | Paper | Qms | 4.8 | N/A | |
| Voice Coil Diameter | 25 mm | Qes | 0.60 | N/A | |
| Nominal Impedance | 8 Ω | Qts | 0.53 | N/A | |
| Sensitivity | 95 dB/W/m | Vas | 76 ltr | N/A | |
| Rated Power | 30W | Le | 0.30 mH | N/A | |
On left - frequency response at 1m with 2.83 V input RED - on axis, BLUE - 15 º off axis, GREEN - 30 º off axis
On right - frequency response smoothed at 1/3 Oct at 0-90º of axis
wit a step of 10º
The second, third and fourth harmonic curves measured at 2.83V input RMS.
Burst decay response, measured at 1m on axis
The impedance curves BLACK - in a free air, BLUE - in 18 ltr sealed volume
Conclusion
The first commercial construction for T215 RTF 64 is Supravox Picola 2 - a double aperiodic vent bookshelf speaker system.
The audiophiles use this driver in various applications.
It is suitable for TQWT or open-baffle constructions, with or
without low frequency support.
My favorite application is Baffles Compensés RJ
which is a combination between a small front panel, with Helmholtz resonator box,
adjusted at 250Hz attached. I recommend it to everyone who doesn't
like the "box" sound. Here are the plans of this construction, as
they were given in the Supravox web page:
In all the application the T215 RTF 64 shows its full-blooded
sound signature. The performance of vocals is expressive and
persuasive. The sound stage is wide and slightly forwarded. This
speaker is very easy to drive and cooperates well with both
push-pull and single ended tube amplifiers.
To The Top