idk, delay reverb?
$$=2**2,$d=24576/$$,del=code=>(this.$T??=0,$T++||($b=[],$B=[]),$=0,lp=(i,f)=>($q=0,$r=$q++,$B[$r]??=0,$B[$r]+=((i)-$B[$r])*f),lp2=(i,f)=>lp(lp(i,f),f),echo=(dly,code,_)=>($++,($b[$]??=($b=Array(dly).fill(0)),ech=(code%256)+$b[t%(dly/2)],$b[t%(dly++/2)]=ech/(_+1),ech/2)),$x=y=>{let $a = 2; let $o=[0,0]; for (let $i=0; $i<$a; $i++){$o[0] += echo(($d)+($i*2**12),lp2(code,.4),$i),$o[1] += echo(($d)+($i*2**1),lp2(code,.7),.5)} return [$o[0],$o[1]]},$x().map(t=>t-1)),$D=code=>del(((code)&255)/256).map(t=>t/2),T=t>>5,m=n=>(2**(1/12))**n,x=t=>[[0,7,10,15],[-2,1,5,8],[-4,0,3,5],[-5,0,3,5]][t>>16&3].map(x=>t*m(x)%256).reduce((a,b)=>a+b)/4,kick=(.999**(t%8192)*1E3&64)*(289>>(T>>8&7)&1),snare=128*sin((t>>(T%128>30?3:4))**7)/max(2,T%128/9)*((T>>7)%8==4)+64,hat=random()*64*(1-t%8192/8192)**3,chords=64*(x(t)/x(t-(8-(t>>13&7)))&1)*(1-t%8192/16384),bass=t*m(-'0245'[t>>16&3]-12*(2-(t>>13&1)))%256/3,$D((kick+snare+hat+chords+bass)/1.5)