VIAWAVE GRT-145-8
VIAWAVE GRT-145-8 — Ribbon Tweeter · Ribbon / Planar Magnetic
95 dB - 8 Ohm - 1,800 – 30,000 Hz - 17 W RMS
Part no.: 42A-CHS-BT-VIA-0002
Documents
VIAWAVE GRT-145-8 — Ribbon tweeter
The original with the patented SRT technology — sealed air gap between ribbon and magnet poles.
95 dB sensitivity · 8 Ω · Frequency range 1.800 – 30.000 Hz
What the SRT technology does
In a classic ribbon tweeter the air gap between ribbon foil and magnet poles is open. Viawave seals it with a U-shaped, heat-resistant polymer film — the patented SRT technology (Sealed Ribbon Tweeter). Two things follow: distortion at the lower end of the range drops markedly, and sensitivity rises by 2 to 3 dB. For a ribbon with only 7 cm² of diaphragm area, 95 dB is an unusual figure.
Technical data
| Nominal impedance | 8 Ω |
|---|---|
| Recommended frequency range | 1.800 – 30.000 Hz |
| Sensitivity (2,83 V / 1 m, 4 – 18 kHz) | 95 dB |
| Power handling, RMS | 17 W |
| Power handling, peak | 40 W |
| Programme power (high-pass 3.000 Hz, 12 dB/oct.) | 150 W |
| Rear chamber resonance | 900 Hz |
| Ribbon dimensions | 14 × 50 × 0.009 mm |
| Ribbon area | 7 cm² |
| Ribbon mass | 0,018 g |
| DC resistance Re | 0,06 Ω |
| Inductance (low frequency) | 7 mH |
| Inductance (high frequency) | 0,034 mH |
| Flux density in the gap | 0,65 T |
| Net weight | 1,32 kg |
Materials
| Ribbon | Aluminium |
|---|---|
| Front plate | Aluminium |
| Magnets | NdFeB |
| Magnetic circuit | Low-carbon steel |
| Rear chamber | Natural wool |
Use
Der Hersteller gibt einen Hochpass ab 3.000 Hz mit 12 dB/Oktave an. Tiefer trennen geht, verlangt aber eine steilere Flanke. Die Belastbarkeitsangabe von 150 W gilt ausdrücklich nur mit dieser Weiche — ohne Hochpass ist ein Bändchen sofort zerstört.
The manufacturer's datasheet with frequency response, impedance and distortion measurements is available for download above. Part no.: 42A-CHS-BT-VIA-0002
Viawave GRT-145-8: ribbon tweeter with sealed air gap, 95 dB at 8 Ω
A ribbon that does not hang open in the magnetic gap – that is the short version of the Viawave GRT-145-8. The patented SRT technique (Sealed Ribbon Tweeter) closes the gap between aluminium foil and poles with a U-shaped, heat-resistant polymer film. The effect is measurable: less distortion at the bottom of the operating range and 2 to 3 dB more sensitivity than an open design. That is how a ribbon with only 7 cm² of area reaches 95 dB (2.83 V/1 m, 4 to 18 kHz) at 8 Ω.
The foil measures 14 × 50 × 0.009 mm and weighs 0.018 g – a moving mass next to which any dome looks heavy. That explains the resolution and the range up to 30,000 Hz. NdFeB magnets with 0.65 T in the gap, a low-carbon steel magnetic circuit, an aluminium faceplate and a rear chamber damped with natural wool complete the driver; weight is 1.32 kg.
Use and enclosure
The 8 Ω version is the uncomplicated choice for passive two- and three-way crossovers and for valve amplifiers whose output transformers work best into 8 Ω. Manufacturer's spec for the crossover: high-pass from 3,000 Hz at 12 dB/octave, at which point the 150 W program rating applies. The operating range starts at 1,800 Hz; crossing lower needs a steeper slope, because 17 W RMS and 40 W peak are reached quickly and the rear chamber resonates at 900 Hz. Without a high-pass the ribbon is destroyed instantly.
For crossover simulation you need the impedance curve, not the nominal figure: the ribbon has 0.06 Ω, the 8 Ω comes from the transformer, and with 7 mH low-frequency and 0.034 mH high-frequency inductance the load is frequency-dependent. When mounting, the 50 mm tall ribbon focuses strongly in the vertical plane; horizontally it radiates wide. So place it at ear level and keep the distance to the midrange short.
What to look out for
- 8 Ω nominal via transformer – uncritical for passive crossovers and valve amplifiers
- High-pass 3,000 Hz, 12 dB/oct as spec; 150 W program applies only with it
- 17 W RMS / 40 W peak – power handling is a crossover question, not an amplifier question
- 1.32 kg, aluminium faceplate, narrow vertical dispersion
Frequently asked questions
Which amplifier suits the GRT-145-8?
Practically any that drives 8 Ω cleanly – valve amplifiers included. At 95 dB the ribbon needs little power; what matters is that the high-pass sits in the crossover rather than expecting the amplifier to provide protection.
Can I cross the GRT-145-8 below 3,000 Hz?
Yes, the range starts at 1,800 Hz. But then with a slope steeper than 12 dB/octave, and the 150 W program rating no longer applies – work with the 17 W RMS.
GRT-145-8 or SRT-7?
The SRT-7 is the modernised version with less roll-off at the bottom of the operating range; figures such as 95 dB, 8 Ω and 1,800 to 30,000 Hz are the same. If you are completing an existing pair or want the original, stay with the GRT-145-8.
Viawave GRT-145-8: manufacturer, spellings and classification
Viawave (Viawave Audio) is the maker of the patented SRT ribbon tweeters with sealed air gap. The GRT-145-8 is a ribbon tweeter, available from 42.audio, Viawave dealer in Germany, with datasheet and full specifications in the driver database.
At 42.audio you get the VIAWAVE GRT-145-8 with all key data in the driver database. More drivers from this manufacturer: Atlas Viawave.
Specifications
| Allgemein | |
|---|---|
| Manufacturer | VIAWAVE |
| Category | Ribbon Tweeter |
| Series | GRT-145 |
| Impedance (Ω) | 8 |
| Power handling (W) | 17 |
| Sensitivity (dB) | 95 |
| Frequency from (Hz) | 1800 |
| Frequency to (Hz) | 30000 |
| Abmessungen & Korb | |
|---|---|
| Weight (kg) | 1.32 |