Manipulate[
Grid[{
{ "Tone sequence (with 0 = middle C) = "},{ RealDigits[N[Trans,maxterms]][[1]][[termslo;;termslo+termstot-1]]//FromDigits},
{Sound[Table[SoundNote[ #+oct,((#+1)^speed)/speed2, inst]&/@ RealDigits[N[Trans,maxterms]][[1]][[termslo;;termslo+termstot-1]],{scale,1,repeat}]]},
{"Filename: "InputField[Dynamic[x],String]},
{"Path: " sPath},
{Button["Export to MIDI file: " Dynamic[x],Export[StringJoin[sPath,x],Sound[Table[SoundNote[ #+oct,((#+1)^speed)/speed2, "Harp" ]&/@ RealDigits[N[Trans,maxterms]][[1]][[termslo;;termslo+termstot-1]],{scale,1,repeat}]],Path->sPath]]}
(*,{InputForm[Sound[Table[SoundNote[ #+oct,((#+1)^speed)/speed2, "Harp" ]&/@ RealDigits[N[Trans,terms]][[1]],{scale,1,repeat}]]]}*)
}],
{{termslo,1,"first term"},1,1000,1,Appearance->"Labeled"},
{{termstot,10,"terms total"},1,maxterms-termslo,1,Appearance->"Labeled"},
{{speed,0,"length/note"},-2,2,Appearance->"Labeled"},
{{repeat,1,"repeat"},1,10,1,Appearance->"Labeled"},
{{oct,0,"octave"},-12,12,12,Appearance->"Labeled"},
{{speed2,1,"speed scaling"},1,20,1,Appearance->"Labeled"},
{Trans,{Pi,E,GoldenRatio,c,Sqrt[2],Exp[-Pi/2],Zeta[3]}},
{inst,instrum},

Initialization:> 
{
c=299792458;
sPath=NotebookDirectory[];
x="default.mid";
maxterms=2000;
instrum={{"Accordion","Agogo","AltoSax","Applause"},{"Atmosphere","Bagpipe","Bandoneon","Banjo"},{"BaritoneSax","Bass","BassAndLead","Bassoon"},{"Bird","BlownBottle","Bowed","BrassSection"},{"Breath","Brightness","BrightPiano","Calliope"},{"Celesta","Cello","Charang","Chiff"},{"Choir","Clarinet","Clavi","Contrabass"},{"Crystal","DrawbarOrgan","Dulcimer","Echoes"},{"ElectricBass","ElectricGrandPiano","ElectricGuitar","ElectricPiano"},{"ElectricPiano2","EnglishHorn","Fiddle","Fifths"},{"Flute","FrenchHorn","FretlessBass","FretNoise"},{"Glockenspiel","Goblins","Guitar","GuitarDistorted"},{"GuitarHarmonics","GuitarMuted","GuitarOverdriven","Gunshot"},{"Halo","Harmonica","Harp","Harpsichord"},{"Helicopter","HonkyTonkPiano","JazzGuitar","Kalimba"},{"Koto","Marimba","MelodicTom","Metallic"},{"MusicBox","MutedTrumpet","NewAge","Oboe"},{"Ocarina","OrchestraHit","Organ","PanFlute"},{"PercussiveOrgan","Piano","Piccolo","PickedBass"},{"PizzicatoStrings","Polysynth","Rain","Recorder"},{"ReedOrgan","ReverseCymbal","RockOrgan","Sawtooth"},{"SciFi","Seashore","Shakuhachi","Shamisen"},{"Shanai","Sitar","SlapBass","SlapBass2"},{"SopranoSax","Soundtrack","Square","Steeldrums"},{"SteelGuitar","Strings","Strings2","Sweep"},{"SynthBass","SynthBass2","SynthBrass","SynthBrass2"},{"SynthDrum","SynthStrings","SynthStrings2","SynthVoice"},{"Taiko","Telephone","TenorSax","Timpani"},{"Tinklebell","TremoloStrings","Trombone","Trumpet"},{"Tuba","TubularBells","Vibraphone","Viola"},{"Violin","Voice","VoiceAahs","VoiceOohs"},{"Warm","Whistle","Woodblock","Xylophone"}}//Flatten;
}


]