Bullet Audio HLCD Specifications
General Specifications
| Frequency Response | 70-20,000 +/- 4 dB | Hz. |
| Sensitivity at 2.83 Volts | 96.12 | dB |
| Power Handling RMS Continuous | 200 | Watts |
| Power Handling Peak | 400 | Watts |
| Nominal Impedance | 4 | Ohms |
Woofer Parameters
| Re | 3.48 | Ohm | electrical voice coil resistance at DC |
| Krm | 0.0004 | WRIGHT inductance model | |
| Erm | 0.93 | WRIGHT inductance model | |
| Kxm | 0.0028 | WRIGHT inductance model | |
| Exm | 0.82 | WRIGHT inductance model | |
| Cmes | 189.77 | µF | electrical capacitance representing moving mass |
| fs | 93.1 | Hz | driver resonance frequency |
| Mms | 18.543 | g | mechanical mass of driver diaphragm assembly including air load and voice coil |
| Mmd (Sd) | 17.342 | g | mechanical mass of voice coil and diaphragm without air load |
| Rms | 1.296 | kg/s | mechanical resistance of total-driver losses |
| Cms | 0.157 | mm/N | mechanical compliance of driver suspension |
| Kms | 6.35 | N/mm | mechanical stiffness of driver suspension |
| Bl | 9.885 | N/A | force factor (Bl product) |
| Qms | 8.371 | mechanical Q-factor of driver in free air considering Rms only | |
| Qes | 0.386 | electrical Q-factor of driver in free air considering Re only | |
| Qts | 0.369 | total Q-factor considering Re and Rms only | |
| Vas | 6.0776 | l | equivalent air volume of suspension |
| n0 | 1.223 | % | reference efficiency (2 pi-radiation using Re) |
| Lm | 93.07 | dB | characteristic sound pressure level (SPL at 1m for 1W @ Re) |
| Lnom | 96.69 | dB | nominal sensitivity (SPL at 1m for 1W @ Zn) |
| Sd | 165.13 | cm² | diaphragm area |
System Responses
Polar Response
Woofer Large Signal Data
| Displacement Limits | Displacement Limits | ||
| X Bl @ Bl min=70% | 5.1 | mm | BL Limited Xmax |
| X C @ C min=50% | 6.2 | mm | Cms Limited Xmax |
| X L @ Z max=10 % | 4.0 | mm | L Limited Xmax |
| Delta Tv = Tv-Ta | 118 | 0 | 0 | K | increase of voice coil temperature during the measurement |
| Re (Tv) | 5.09 | 3.51 | 3.51 | Ohm | voice coil resistance considering increase of voice coil temperature Tv |
| Le (X=0) | 0.58 | 0.58 | 0.49 | mH | voice coil inductance at the rest position of the voice coil |
| L2 (X=0) | 0.83 | 0.83 | 0.46 | mH | para-inductance at the rest position due to the effect of eddy current |
| R2 (X=0) | 2.67 | 2.67 | 2.33 | Ohm | resistance at the rest position due to eddy currents |
| Cmes (X=0) | 281 | 281 | 211 | µF | electrical capacitance representing moving mass |
| Lces (X=0) | 20.42 | 20.42 | 17.21 | mH | electrical inductance at the rest position representing driver compliance |
| Qms (X=0, Tv) | 4.67 | 4.67 | 2.05 | mechanical Q-factor considering Rms only | |
| Qes (Tv) | 0.39 | 0.27 | 0.34 | electrical Q-factor considering Re (Tv) only | |
| Qts (X=0, Tv) | 0.36 | 0.26 | 0.29 | total Q-factor considering Re (Tv) and Rms only | |
| fs | 66.4 | 66.4 | 83.5 | Hz | driver resonance frequency |
| Mms | 21.210 | 21.210 | 21.210 | g | mechanical mass including air load |
| Rms (X=0) | 1.893 | 1.893 | 5.438 | kg/s | mechanical resistance of total-driver losses |
| Cms (X=0) | 0.27 | 0.27 | 0.17 | mm/N | mechanical compliance of driver suspension at the rest position |
| Bl (X=0) | 10.68 | 10.68 | 10.68 | N/A | (imported) force factor at the rest position (Bl product) |
| Vas | 10.4199 | 10.4199 | 6.5875 | l | equivalent air volume of suspension |
| N0 | 0.740 | 1.073 | 1.073 | % | reference efficiency (2Pi-sr radiation using Re) |
| Lm | 90.8 | 92.5 | 92.5 | dB | characteristic sound pressure level |
| Sd | 165.13 | 165.13 | 165.13 | cm² | diaphragm area |
Non-Linear Curves
Summary of improvements on new Bullet Audio 7.7 driver
Bullet Audio has made substantial changes to the 7.7 speaker. This includes changes in woofer, tweeter and crossover. This memo highlights the changes and documents the improvements in performance.
Woofer
The cone and motor geometry were modified to improve linearity and frequency response. This can be seen by a comparison of the frequency response graphs on the raw woofers:
The new woofer has solved the issue of the substantial dip at 3 kHz. which will make the system response far smoother in this range and improve the clarity of the overall product (improved sibilance).
Non-Linear performance
The new woofer also has higher maximum SPL due to improved motor symmetry. This can be seen by the Klippel Non-linear limits. These are taken as a set to define Xmax:
| Displacement Limits | Original | New | ||
| X Bl @ Bl min=70% | 4.4 | 5.1 | mm | BL Limit |
| X C @ C min=50% | 7.0 | 6.2 | mm | Cms Limit |
| X L @ Z max=10 % | 3.6 | 4.0 | mm | L Limit |
These improvements can also be seen in the distortion curves (much lower from 1 kHz. to 6 kHz.) The lower 3rd harmonic distortion should be audible and a clearer vocal range –especially female vocals.
Original Woofer
New Woofer
Tweeter and crossover
The tweeter motor was changed to Neodymium material for to improve response, sensitivity and distortion. The crossover was also modified to take advantage of the improved woofer response. This combination gives flatter response in the high frequencies and lower distortion.
