In this blog post I test the 18Sound ND1480BE Beryllium compression driver. This driver retails for €1,350.00 each ($1,485 USD).
- 3 inch premium Beryllium dome -
- polymer surround diaphragm
- Extended HF with minimal breakup
- 112 dB 1W / 1m average sensitivity
- 1.4 inch throat exit
- 3 inch edgewound aluminum voice coil
- HF copper sleeve for reduced distortion and increased output
Below is the published data from the manufacturer. The impedance sweep shows the FS centered around 460Hz with the first breakup showing up at 17kHz.
The published response shows the typical CD Horn falling response. The horn used in the published data was the XR1464C.
My Own Measurements
For this test I used the ES-600 Biradial which is shown below. The horn uses a standard 1.40" throat diameter with a 600Hz cutoff Frequency (Fc).
Below is the measured impedance and phase response for the ND1480BE. The mechanical resonance (FS) is centered at 460Hz which closely matches published. The first mechanical breakup occurs at 16.5kHz
The first mechanical breakup occurs at 16.5kHz as you can see below.(zoomed)
With the mic positioned at 30cm, I measured the burst decay using a 5.66ms gate. I also used the 3.9uF capacitor to flatten the response somewhat for this measurement.
Below is the CSD plot. We can see that
Below is the harmonic distortion result for the 85dB test signal level at 1m. The mic was placed 15cm from the horn mouth. H2 remains below 0.10% for most of the spectrum with H3 and H4 at 0.015% and 0.00613% respectively. Raising the test signal to 95dB we see a modest increase in H2 with H3 and H4 remaining very low at 0.037% and 0.00685% for the 600Hz region.
If looking at the same results but with the vertical scale changed to dB instead of percent, we get the following for the 85dB test signal level.
For the 95dB test signal level we get the following.
For comparison's sake I've shown the Eminence N314X below.
I then measured intermodulation distortion using a 12 band per octave test signal ranging from 600Hz to 20kHz set to 85dB SPL at 1m.
Raising the test SPL to 95dB is shown below.
I decided to limit the test signal to 1kHz and above. This should reduce the amount of modulation into the upper frequencies generated by the lower tones.
Again, at the 95dB test signal level.
Subjective Listening Impression Ranking
With the speakers setup as a stereo pair, I evaluated using a 2-way setup. Bass frequencies were handled by the Fostex 8" (FW208HS) in a 40L cabinet tuned to 35Hz. The high pass filter was a single capacitor (3.9uF) followed by a fixed resistor L-Pad comprised of a 6.8ohm (R1) and 1.5ohm (R2). This provided -16dB of attenuation to match the 90dB sensitivity of the Fostex 8".
Soundstage Depth --- 9/10
Soundstage Width --- 8/10
Smoothness --- 10/10
Coherence between midrange and treble --- 10/10
Vocal Clarity Male --- N/A mostly evaluated 600Hz and above
Vocal Clarity Female --- 10/10
Accurate Musical Instrument timbre --- 10/10
Sense of Dynamic Range: --- 10/10 Provided the same dynamics as titanium but without the metallic sound signature.
General Thoughts on Sound Character
The ND1480BE surprised me for its ability to reproduce upper frequencies with precision and accuracy. Cymbals and electric guitar was faithfully rendered in terms of texture and nuance, but also with proper dynamics. The driver does not sound soft, but exerts itself with confidence and grace. The midrange and treble offers excellent clarity, allowing the listener to hear new elements of the track that was hidden before. As I play track to track, each recording takes on a unique character that is colorful and engaging.
My listening impressions on the ND1480BE left me impressed. The driver provides impeccable measurements as well, especially in the 6kHz-12kHz region.