A noise cancellation enabled audio system for tonal tinnitus treatment using ambient noise, comprising: - an audio processor (PROC), - at least one filter having an adjustable filter function, and - an ear mountable playback device further comprising a speaker and at least one feedforward microphone (FF_MIC), wherein the audio processor (PROC) is configured to: - receive an input signal (Z(s)) from the feedforward microphone (FF_MIC) indicative of ambient noise, - determine a filter transfer function (HF(s)) to realize a predetermined target transfer function (HT(s)), wherein the target transfer function (HT(s)) is configured to attenuate and/or amplify the input signal (Z(s)) in a predetermined frequency range, and - adjusting the filter function depending on the filter transfer function (HF(s)); and wherein the filter is configured to: - provide a system output signal (Y(s)) by filtering the input signal (Z(s)) depending on the filter function, and wherein: - the audio processor (PROC) is provided with acoustic transfer functions between an ambient sound source creating the ambient noise and an eardrum exposed to the speaker, and - the audio processor (PROC) is configured to determine the filter transfer function (HF(s)) by compensating for the acoustic transfer functions; - the noise cancellation enabled audio system further comprising an amplifier coupled between the audio processor (PROC) and the speaker, and wherein the acoustic transfer functions comprise: - a first acoustic transfer function (HM(s)) of the feedforward microphone (FF_MIC), denoted H M (s), - a second acoustic transfer function (HA(s)) of the amplifier, denoted H A (s), - a third acoustic transfer function (HS(s)) of the speaker, denoted H S (s), - a fourth acoustic transfer function (HH(s)) of the ear mountable playback device, denoted H H (s); and wherein: - the filter transfer function (HF(s)), denoted H F (s), is determined as H F s = H T s − H H s H M s ⋅ H A s ⋅ H S s wherein H T (s) denotes the target transfer function (HT(s)); the noise cancellation enabled audio system further comprising a feedback noise microphone (FB_MIC) located in proximity to the speaker, and wherein the fourth acoustic transfer function (HH(s)) comprises a passive damping component due to the ear mountable playback device and an active damping component due to active noise cancellation by means of the feedback noise microphone (FB_MIC). - an audio processor (PROC), - at least one filter having an adjustable filter function, and - an ear mountable playback device further comprising a speaker and at least one feedforward microphone (FF_MIC), - receive an input signal (Z(s)) from the feedforward microphone (FF_MIC) indicative of ambient noise, - determine a filter transfer function (HF(s)) to realize a predetermined target transfer function (HT(s)), wherein the target transfer function (HT(s)) is configured to attenuate and/or amplify the input signal (Z(s)) in a predetermined frequency range, and - adjusting the filter function depending on the filter transfer function (HF(s)); and - provide a system output signal (Y(s)) by filtering the input signal (Z(s)) depending on the filter function, and wherein: - the audio processor (PROC) is provided with acoustic transfer functions between an ambient sound source creating the ambient noise and an eardrum exposed to the speaker, and - the audio processor (PROC) is configured to determine the filter transfer function (HF(s)) by compensating for the acoustic transfer functions; - the noise cancellation enabled audio system further comprising an amplifier coupled between the audio processor (PROC) and the speaker, and wherein the acoustic transfer functions comprise: - a first acoustic transfer function (HM(s)) of the feedforward microphone (FF_MIC), denoted H M (s), - a second acoustic transfer function (HA(s)) of the amplifier, denoted H A (s), - a third acoustic transfer function (HS(s)) of the speaker, denoted H S (s), - a fourth acoustic transfer function (HH(s)) of the ear mountable playback device, denoted H H (s); and wherein: - the filter transfer function (HF(s)), denoted H F (s), is determined as H F s = H T s − H H s H M s ⋅ H A s ⋅ H S s - a first acoustic transfer function (HM(s)) of the feedforward microphone (FF_MIC), denoted H M (s), - a second acoustic transfer function (HA(s)) of the amplifier, denoted H A (s), - a third acoustic transfer function (HS(s)) of the speaker, denoted H S (s), - a fourth acoustic transfer function (HH(s)) of the ear mountable playback device, denoted H H (s); and - the filter transfer function (HF(s)), denoted H F (s), is determined as H F s = H T s − H H s H M s ⋅ H A s ⋅ H S s the noise cancellation enabled audio system further comprising a feedback noise microphone (FB_MIC) located in proximity to the speaker, and wherein the fourth acoustic transfer function (HH(s)) comprises a passive damping component due to the ear mountable playback device and an active damping component due to active noise cancellation by means of the feedback noise microphone (FB_MIC).