HTP-1 Installation and User Guide Release 1.8.1
The input sensitivity of an amplifier is commonly reported in its user guide as a specification. The
maximum output voltage should ideally match the input sensitivity of your amplifier. If the input
sensitivity of your amplifier is unknown, begin by setting maximum output level of the HTP-1 to 1 volt.
Set the max listening volume to zero. Run the volume up and see if it gets as loud as you want it to be. If
you think it should be louder, increase the maximum output level. Doubling the maximum output
voltage will increase volume by 6dB. You can repeat this procedure, increasing the maximum output
voltage until the system is as loud as you want it and as loud as your amps and speakers can sustain. 4v
RMS is the maximum supported output level. The maximum output level is designed to match common
balanced amplifiers. If you are using an unbalanced amplifier connection then you should expect to use
a maximum output level twice that of an unbalanced amplifier because it is single ended.
Recommendations on setting the Maximum Output Level
1. A proper technical way to align the volume is to use the signal generator producing “THX-like”
pink noise at -30dBFS. Set the volume control to 0 dB and then adjust the maximum output
level until you register 75 dB on an SPL meter. Feel free to read about the THX calibration
method elsewhere. It’s OK if your system cannot reach this volume using your amplifiers and
speakers. This is quite loud. You will have an idea of how close you can get.
2. Setting the volume control to zero dB causes the output to drive the maximum output level
using a full scale sine wave as a reference signal and having minimal digital headroom. Setting
the volume control above zero dB makes it possible to clip (distort) high level input signals. This
should be appropriate only for very quiet source material.
3. Setting the maximum output level to a high value makes it possible for you to sometimes hear a
small tick when mute is engaged. If you notice this, you might try lowering the maximum output
level.
4. The minimum distortion is measured with the maximum output level near 2.2v. Higher settings
raise the analog gain with the resulting small rise in distortion.
5. If you continually listen at very low volumes (like -40 or -50) you are giving up dynamic range
and operating closer to the noise floor of the system. This may be OK, but it may be better to
lower the maximum output level.
6. If you find yourself turning the output volume up over zero dB you are making it possible for
loud material to distort (clip). It would be better to raise the maximum output level, or invest in
larger amps and/or more sensitive speakers.
Lipsync Delay
The lipsync delay setting applies to all channels. It can apply up to 200ms of additional delay to the
audio signal. The amount of lipsync delay required typically depends on the type of video system in use.
Systems designed for gaming try to have minimum delay. Advanced motion compensation systems
found in high end TV’s might add more delay to the video signal.
HTP-1 User Manual
Page 47
V1.8.1