In Crossing the Bridge, German-born director Fatih Akin returns to his native Turkey to film a documentary exploration of Istanbul's contemporary music. He travels with German musician Alexander Hacke – whom he first met while recording the soundtrack to his successful and controversial 2004 film Head On – as he searches for the sound of the streets: the native rhythm coursing through the veins of Istanbul's diverse cultures and traditions.

At the heart of the film is a contemplation of an east/west cultural divide, a topic which holds particular currency these days, as controversial events repeatedly raise the spectre of an intrinsic clash between the two civilisations. Almost immediately, Akin presents his bold counter-argument through the words of Richard Hammer, the saxophonist from Orient Expressions: "The idea that the East is East and the West is West and never the twain shall meet – that's bullshit. That is a historical lie."

"When you live here," explains Murat Uncouglu, one of the group's DJs, "your ears are open to everything". He makes a contrast with US hip-hop. While hip-hop is microscopically local, with every neighbourhood producing its own genre and sub-genre, its own vocabulary and voice, Istanbul's musicians revel in their internationalism and take pride in the wide range of influences from which they draw. For them, there is nothing unusual about mixing American, Turkish and European styles.

The reason is obvious: Turkey itself has long been a bridge between "east and west", not only literally (3% of her landmass is officially in Europe) but culturally. Musicians here are therefore able to achieve an organic melding of eastern and western styles, influences and traditions without the tedium and pastiche of other so-called fusion genres. While it may not always be highly original, it is nonetheless honest and instinctive, reflecting a process of absorbing a foreign style and ultimately making it Turkish through language, context and philosophy.

Crossing the Bridge is at its most interesting when it shifts focus from Turkey's musical relationship with the rest of to world to its musical relationship with itself. We are introduced to Erkin Koray, Turkey's answer to Jimi Hendrix, as he describes how, when he first appeared, the establishment was shocked: "I had to deal with resistance from the very beginning. Even today I can't do what I want." In the 1960s, his experiments – performing Turkish music with amplified instruments and covering the Beatles and the Rolling Stones on Turkish instruments – were seen as evidence of the west's decadent influence creeping into Turkish culture. It was rather an odd objection for a country that, less than forty years earlier, was aggressively suppressing its own traditional culture in favour of European influences under Kemal Atatürk's republican reforms.

Akin's documentary reveals Turkey's swinging pendulum of reform and revival: a generation after Atatürk the country's musicians are scrambling to preserve those very same traditions that were once abandoned for the sake of progress. Though the film doesn't directly address the policies of Atatürk – it is not, after all, a historical documentary – his legacy clearly reverberates throughout the music. And Turkey's 1980 military coup represented a more recent threat to the country's traditional character, putting further strain on the country's cultural survival when it banned the Kurdish language (among other things) and made the performance of Kurdish music illegal.

As a result, until Kurdish music was finally legalised in 1991, performers like Aynur – one of the country's modern Kurdish voices – were labelled criminals, separatists and even traitors. That atmosphere of paranoia and suppression lent a new poignancy to the already heartbreaking dirges of Kurdish music, infusing the traditional cries and lamentations with a contemporary urgency. In one of the film's most striking scenes, a homeless street musician speaks of seeing Kurdish houses burned down by Turkish vigilantes while the voice of Aynur creeps, ethereally, into the soundtrack, her lyrics evoking a homeland that has never been. Akin's technique gels beautifully, flirting with nostalgia, but never crossing into tackiness.

With segments like these, Akin manages to reference the political without overtly addressing it. He maintains the musical atmosphere of Istanbul, like the jazz of New Orleans, as an integral part of the city, a living reflection of Istanbul's soul. Through cinematic "dialogues" with musicians, rather than traditional, formal interviews, he gives us the feeling that we are privy to fragments of a personal conversation. They cleverly balance between exposition and intimacy, always relevant yet never rushed or forced, giving the impression that the film is as much an exploration for the director as it is for the viewer.

There is, at times, a sublime overlap between what Akin is doing with his film and what many of the performers are doing with their music: preserving the precious, ephemeral moments of unique musical experiences. Brenna MacCrimmon, for example, has made it her own personal mission to revive a rare folk style originally performed by Turkish musicians from Bulgaria. Selim Sesler has a similar compulsion: a master of Turkey's gypsy musical style, once resented by mainstream Turkish culture, he is now the country's best-known gypsy musician and plays a central role in developing appreciation of the more obscure and diverse elements of the Turkish character.

It is in this opposition, between innovation and preservation, that the film is at its most intriguing, but it is sadly also the point at which Hacke's role as presenter/explorer fails most obviously. His goal – "I decided to capture the sounds of this city in order to figure them out" – is painfully naïve, and reveals a distinctly narrow approach, verging on Orientalism, that seems inadequate at best, and insulting at worst. He appears, for most of the film, to be little more than a cultural tourist, not so much interacting with the musicians as collecting them with an anthropological zeal for empirical data. He seems to believe that somehow, by listening to his recordings and talking with the musicians, he can objectively define a single entity and call it "Turkish music". When he joins musicians to perform, the sessions lack the organic synthesis that Hacke is clearly aiming for, and he comes across as an awkward gatecrasher rather than an artistic collaborator.

It is ironic that, while the film's musicians so adamantly stress their pan-European and Asian identities, Hacke still approaches the task as a European investigating a foreign culture. Herve Dieu's camerawork so skilfully expresses the relationship between art and the urban character of Istanbul that the film is at its most fluid when the camera alone tells the story: Hacke's segments appear forced and hackneyed by comparison.

As a European-born Turk himself, Akin is in a perfect position to look at Turkish culture from within an east/west context without overplaying either perspective. Like the dichotomy between pain and joy that permeates much of the music, he weaves the dark and light sides of Istanbul's music scene with the political and the cultural, as they rub up against pure energy, innovation and pop sensibilities, to produce a portrait of the city's music as one among many facets of Istanbul's complex character.