Loudspeaker Test Oscillator
Models LTO1, LTO2 and LTO4
The LTO Series are Power Sweep Oscillators designed specifically for testing loudspeaker drive units or finished loudspeakers. Front panel controls are kept to the minimum required by the test operator, with other parameters preset internally for stability and security. These oscillators are rugged professional instruments designed to operate day in day out in a production line environment.
All model offer these Key Features:
- High quality Sine wave with <0.3% distortion at 1kHz
- 15 Hz to 20 kHz in a single sweep
- Smooth continuous logarithmic sweep without steps or glitches
- High power output
- Auto and manual sweep
- Output short circuit proof
- In addition to the above, the LTO4 features:
- 60 Watts into 2 Ω
- Special dual-rate/dual-level sweep
- Polarity test signal
- Automatic test start when loudspeaker load connected
- Various options are available and custom modifications can be incorporated.
The LTO Range are Power Sweep Oscillators that produce a high quality, low distortion sine wave for testing loudspeaker drive units or finished loudspeakers. The frequency may be swept either manually or automatically in a continuous logarithmic scale from 15Hz to 20kHz. The built-in power amplifier will drive up to 11 volts into speakers down to 2Ω (LTO4 only), ideal for "rub and buzz" testing.
The LTO4 features a special multi-sweep test with an automatic start-up. The test sequence starts immediately a loudspeaker load is connected. A short unipolar DC pulse is first applied to the speaker to check polarity. After the DC pulse the first part of the sweep starts at 20kHz, sweeping down to 200Hz with the output level set from the front panel and sweep rate preset internally. The sweep then changes to a second preset rate and level (adjustable from the front panel) which sweeps from 200Hz down to 20Hz, then reverses direction and sweeps back up to 200Hz. The output continues to sweep back and forth between 200Hz and 20Hz for "rub and buzz" testing until the loudspeaker load is disconnected when the LTO4 automatically resets itself in preparation for the next test.
| Specifications | LTO1 | LTO2 | LTO4 | LTO4X | |
| Frequency range | 15Hz to 20,000Hz | YES | YES | YES | YES |
| Auto Sweep | 15Hz-20kHz Single Logarithmic Sweep | YES | YES | NO | NO |
| 20kHz to 15Hz (slope changes at 200Hz – see Fig. 1) | NO | NO | YES | YES | |
| Sweep Start | Using START button | YES | YES | NO | NO |
| Auto on Connecting Speaker (1) | NO | NO | YES | YES | |
| Automatic sweep time | 1 – 15 s, set by Front Panel Control | YES | YES | NO | NO |
| Dual sweep times set internally (see Figure 1). | NO | NO | YES | YES | |
| Manual sweep mode | Frequency, by single turn control (rated for 50,000 rotations) (2) | YES | YES | YES | YES |
| Crossover Testing | Facility for test Crossover wired speakers 1µF to 47µF | NO | NO | NO | YES |
| Output waveform | Sine wave with THD <0.3% at 1kHz | YES | YES | YES | YES |
| Output voltage | 8 Vrms max into ≥ 4 Ω (adjustable) | YES | YES | NO | NO |
| 11 Vrms max into ≥ 2 Ω Dual levels (adjustable) (see Fig. 2) | NO | NO | YES | YES | |
| Amplitude flatness | <±0.5dB, 20Hz-20kHz | YES | YES | YES | YES |
| Polarity test | 1A d.c. pulse for approx. 0.3 s (see Figure 3) | NO | NO | YES | YES |
| Output protection | The output is short circuit proof and with a front panel fuse for additional protection. | 5A Fuse | 5A Fuse | 6.3A Fuse | 6.3A Fuse |
| Output overload indicator | NO | NO | YES | YES | |
| Frequency display | 5 digit. Accuracy ±1Hz | NO | YES | YES | YES |
| Voltage display | 3½ digit. Accuracy ±1% of maximum output | NO | YES | NO | NO |
| 4½ digit. Accuracy ±1% of maximum output | NO | NO | YES | YES | |
| Power supply | 230V/115V AC ±10% | 50VA. | 50VA. | 200VA. | 200VA. |
| Voltage selection | Internal wiring | Internal wiring | Rear panel switch | Rear panel switch | |
| Dimensions | (WxDxH) | 291x191x108 | 231x191x108 | 231x291x169 | 231x291x169 |
| Weight | 2.5kg | 2.5kg | 6kg | 6kg | |
Custom Variations:
Due to the modular construction of these products, we are able to quote prices for variations to suit your particular requirements. Please contact David Evans to discuss your application.
Notes:
- (1) A continuous logarithmic sweep starts automatically when a load is connected.
- (2) For Extended Manual operation, an alternative control rated at 1,000,000 rotations can be fitted
Common features:
| Power cord | 2m detachable cable with moulded IEC connector and mains plug |
| Cabinet | Rugged high quality ABS case with tilt foot |
| Warranty | 12 months |
For information regarding Myryad’s professional products, including the LTO range, please contact David Evans at:
Myryad Systems Ltd., 2 Pipers Wood, Waterberry Drive, Waterloovile
Hampshire, PO7 7XU
Tel: +44 (0) 23 9226 5508, Fax: +44 (0) 23 9223 1407
Email: lto@myryad.co.uk
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