BRT VRT ZRT KRT is the first trumpet solo album by Mazen Kerbaj. It was recorded in 2004 and 2005.
It is also the first album released by Al Maslakh, the label that Kerbaj co-founded with guitarist Sharif Sehnaoui in 2005 to "publish the unpublishable on the Lebanese artistic scene".

Mazen Kerbaj is widely considered as one of the initiators and key players of the Lebanese free improvisation and experimental music scene. He is co-founder and active member of MILL, the cultural music association behind Irtijal, an annual improvisation music festival held in Beirut since 2001 (www.irtijal.org), and co-founder of Al Maslakh, the first label for experimental music in the region operating since 2005 (www.almaslakh.org). 
As a trumpet player, whether in solo performances or with long-lasting groups like “A” Trio, Kerbaj pushes the boundaries of the instrument and continues to develop a personal sound and an innovative language, following in the footsteps of pioneers like Bill Dixon, Axel Dörner and Franz Hautzinger.

Playing in solo has always been an important part of Mazen Kerbaj’s musical journey; it is in this bare-bones setup that he can experiments the most with his instrument, pushing it beyond any recognition. His use of various every-day objects (tubes, plastic bowls, balloons, aluminum foil…) to “prepare” the trumpet, and his unique playing techniques allow him to create raw soundscapes that sound sometimes like electronics (he describes himself his trumpet playing as “playing electronic music, acoustically”), especially when he plays several continuous layers of sound at the same time on an instrument that is not designed for that.
Be it in his various recordings or in live concerts, in acoustic or in amplified setups, Kerbaj’s trumpet solos never fail to surprise.

On the back cover it says 'no cuts, no overdubbing, no use of electronics', and especially the latter is hard to believe.
[Vital Weekly - Frans de Waar]

At the end of the recording, you're left asking yourself - were any of these sounds processed? Then you stare at the CD sleeve, where it clearly states "no use of electronics". If that's the case, a big round of applause goes out to Mazen, as I had no idea the trumpet had such a heavy split personality disorder.
[Tom Sekowski – Gaz-Eta]

Mazen Kerbaj is an astounding improviser, as clearly demonstrated by this adventure for solo trumpet. On the CD cover, he writes "No cuts, no overdubbing, no use of electronics"; he's right in advising us, because the sounds emitted by his instrument are beyond the limits of believable. Each track is aptly titled with a tentative onomatopoeic transcription of the noises he generates - there is some fabulous poetry here, just listen to "Tagadagadaga" or "Flooka Brooka Clooka" to realize that they truly sound that way.
Music made with few means, exquisitely mature in its conscious suggestive force, "Brt Vrt Zrt Krt" is a necessary addition in every serious collection of contemporary creativity.
[Massimo Ricci – touching extreme]

Over the course of an hour, Kerbaj delivers 15 incisive performances which focus on the instruments basic sonic and idiomatic properties – breath in the bell, the sharp click of the valves, and so forth. Kerbaj specializes in the low and the flatulent, but even in these registers his improvising isn’t declamatory (like, say, the great Bill Dixon) as much as it is furtive. Rather than splashing paint on a canvas, he traces invisible shapes in the air.
[Jason Bivins – Dusted Magazine]

If these records are any indication, Kerbaj is not likely to be remembered solely as a rainmaker; he’s one hell of a trumpeter too. He works in roughly the same trumpet-as-sound generator vein as Hautzinger, Axel Dörner, and Greg Kelley, but he developed his style in relative isolation and it’s all his own. Brt Vrt Zrt Krt is an aptly onomatopoeic title; using metal plates as mutes and rubber tubes to connect his horn to a saxophone mouthpiece, Kerbaj coaxes all manner of unearthly squeals, whistles, whooshes, and clatters from his instrument.
But Kerbaj’s radical sounds are means, not ends; he uses them to the listener on a trip in which one’s sense of the expected is undermined and one’s hackles can’t help but rise.
[Bill Meyer – Signal To Noise]

His trumpet playing is certainly unorthodox: he sits down, holds it between his knees and even manages to play it simultaneously with assorted percussion instruments. Circular breathing, it goes without saying, comes naturally. Kerbaj extends the trumpet to the point of almost abandoning it completely, going way beyond Axel Dörner's steam engine huff and puff and the quarter-tone exhalations of Franz Hautzinger. Every piece on this disc explores a different technique, and it sounds like Kerbaj has been developing them for a long time. 
For all its experimental rigour, this music really swings!
[Vid Jerast - Paris Transatlantic]