Maximum noise shaping order

[fonograph]

There is music format introduced in the 90s by Sony called DSD,its 1 bit pulse density modulation with 7th order noise shaping,it runs at 2.8MS/s.There is also DAC from company called Mola Mola that uses 7th order noise shaping to convert the incoming 16bit 44100KS/s pulse code modulation into 100 MS/s 1bit pulse width modulation.

Why 7th order? I understand that in sigma delta ADC its hard to design high order noise shaping becose it must be analog,that means IIR filters only,that means feedback and stability problems as the order increase so they are mostly around 4th order,atleast thats what I saw I am no expert on sigma delta converters.

But this is all digital domain,FIR filters.... instability,not even once,engineering challenges,not even once.With modern computers its not any harder to make 8th order or 9th order that it is to make 7th order.Why its 7th order? Why not more?
For each increase of the noise shaping order,the more dynamic range we get at low audio frequencies.

What is the reason to choose 7th order? Since this is digital noise shaping and filtering,isnt higher order noise shaping simply better? Are there some  negatives that I dont know about?

I get that at 16bit 44100 KHz noise shaping,you cant go crazy on the noise shaping filter order becose there is like 1/6th of octave above 20KHz to push the noise into inaudible region,but the dsd is running at almost 3 MHz,thats many octaves to push that noise into,and the Mola dac is running st 100 MHz,I just dont see the reason why 7 is such magical number when it comes to noise shaping.It sort of triggers me becose I am obsessive even order binary perfectionist,I would if anything expect it to be 8th order.

[tszaboo]

7x20dB is 140dB. You never hear that big dinamic range.

[fonograph]

7x20dB is 140dB. You never hear that big dinamic range.

I dont care if its audible or not,I dont even care about that music format or dac.I only want to know if its possible to make higher order noise shaping,and what are negatives of higher order noise shaping.

And even the argument that why put higher order when 7th order is already good enough for 140db,I ask then,why they didnt make the sample rate half and increase the order to get the same dynamic range? If there are no negatives or limits to digital noise shaping filter order,it doesnt make sense to use anything less than maximum filter order in order to use as low sample rate as possible to minimize the audio file size.