Jan Meier
King Corda
Member of the Trade: Meier Audio
- Joined
- Jun 21, 2001
- Posts
- 854
- Likes
- 182
Dear Headfellows,
To gain or not to gain, that's the question.
There's no such thing as an optimal gain for headphone amplifiers. A lot depends on the specific setup used and on the listening habits of the user.
The main factors are:
- The sensitivity of the headphone used. This one can vary a lot. For instance the HD600 produces 107 dB at 1 Volts where as the HD25-1 produces 143 dB at the same output signal! And a K601 is even less sensitive then the HD600. Therefore a range of 40dB between the various headphone models is not unrealistic.
- The output signal of the source. Regular CD-players have a maximum output signal of around 2 Volts but certain DACs go up to 4V values! On the other hand portable MPEG-3 players, limited by their powersupply of just 1.5 Volts, have a typical output signal that can be as low as just 400 mV. This is a 20 dB difference!
- The music listened to. Popular music has generally low dynamics. The sound level varies relatively little and the signal is recorded near maximum level continously. However, with modern symphonic music the soft passages are often recorded at a low level in order to record the very loud passages without any distortion. Therefore classical music often needs more amplification then popular music. The difference can be easily 10..20 dB.
- Listening habits. Some people like to listen at very high sound levels (headbangers), other people prefer to save their hearings. Again differences of 10..20 db with the same kind of music are not uncommon.
The difference between the two most extreme situations thus can be upto 100 dB! The amplification factor of any headphoneamp therefore has to be a compromise. At a very low gain factor not enough sound pressure will be produced at certain situations. At a very high gain factor the volume control will work at a region of non-optimal performance (channel-imbalances) and noise and distortion will be unnecessarily increased.
The ARIA was designed to work optimal with a 2 Volts input (regular CD-player) even if a high impedance headphone like the DT880 or HD650 is used. Unfortunately the internal USB-DAC chip provides a signal that is 6 dB lower than that of a CD-player. Therefore the maximum output signal using the USB-DAC is limited to 2.8 Volts (2 Volts RMS). But even with a DT880 this results in a rather unhealthy maximum sound level of around 113 dB!
A word of care!
While listening to headphones we lack several feedback mechanisms on volume level that are present when we listen to loudspeakers. Much less distortion, no feeling of the lower frequencies by our body and no psychological restraints not to annoy our fellow-men easily seduces us to listen at volume levels that are detrimental to our hearing.
Hearing damage from regular exposure to high sound levels progresses slowly but is irreversible and can result in permanent hearing loss.
!!!! Please choose your volume setting with caution !!!!
Personally I would recommend against an increased amplification factor. Increased noise/distortion and poor volume control when low impedance headphones are used. Moreover, a lower amplification factor will force you to listen at saver sound levels. The primary idea behind a headphoneamplifier is to improve on sound quality, not on its quantity!
But that's my opinion. If people like a higher gain setting then that's what they will get. However, be aware that there's no 30 day return policy on amplifiers that have been modified custom-specific.
Cheers
Jan
To gain or not to gain, that's the question.
There's no such thing as an optimal gain for headphone amplifiers. A lot depends on the specific setup used and on the listening habits of the user.
The main factors are:
- The sensitivity of the headphone used. This one can vary a lot. For instance the HD600 produces 107 dB at 1 Volts where as the HD25-1 produces 143 dB at the same output signal! And a K601 is even less sensitive then the HD600. Therefore a range of 40dB between the various headphone models is not unrealistic.
- The output signal of the source. Regular CD-players have a maximum output signal of around 2 Volts but certain DACs go up to 4V values! On the other hand portable MPEG-3 players, limited by their powersupply of just 1.5 Volts, have a typical output signal that can be as low as just 400 mV. This is a 20 dB difference!
- The music listened to. Popular music has generally low dynamics. The sound level varies relatively little and the signal is recorded near maximum level continously. However, with modern symphonic music the soft passages are often recorded at a low level in order to record the very loud passages without any distortion. Therefore classical music often needs more amplification then popular music. The difference can be easily 10..20 dB.
- Listening habits. Some people like to listen at very high sound levels (headbangers), other people prefer to save their hearings. Again differences of 10..20 db with the same kind of music are not uncommon.
The difference between the two most extreme situations thus can be upto 100 dB! The amplification factor of any headphoneamp therefore has to be a compromise. At a very low gain factor not enough sound pressure will be produced at certain situations. At a very high gain factor the volume control will work at a region of non-optimal performance (channel-imbalances) and noise and distortion will be unnecessarily increased.
The ARIA was designed to work optimal with a 2 Volts input (regular CD-player) even if a high impedance headphone like the DT880 or HD650 is used. Unfortunately the internal USB-DAC chip provides a signal that is 6 dB lower than that of a CD-player. Therefore the maximum output signal using the USB-DAC is limited to 2.8 Volts (2 Volts RMS). But even with a DT880 this results in a rather unhealthy maximum sound level of around 113 dB!
A word of care!
While listening to headphones we lack several feedback mechanisms on volume level that are present when we listen to loudspeakers. Much less distortion, no feeling of the lower frequencies by our body and no psychological restraints not to annoy our fellow-men easily seduces us to listen at volume levels that are detrimental to our hearing.
Hearing damage from regular exposure to high sound levels progresses slowly but is irreversible and can result in permanent hearing loss.
!!!! Please choose your volume setting with caution !!!!
Personally I would recommend against an increased amplification factor. Increased noise/distortion and poor volume control when low impedance headphones are used. Moreover, a lower amplification factor will force you to listen at saver sound levels. The primary idea behind a headphoneamplifier is to improve on sound quality, not on its quantity!
But that's my opinion. If people like a higher gain setting then that's what they will get. However, be aware that there's no 30 day return policy on amplifiers that have been modified custom-specific.
Cheers
Jan
