Zebra_PD

96 in/out routing in a 19" rack?
« on: July 24, 2019, 10:59:07 AM »
I have been playing with the idea of building a 32×32×32 analog router/switch to be able to easily make use of all our outboard EQ, pre and comps both during tracking and mixing without having to change a million patch cables in our current three patch bays every time.

Have it in a 2U 19" rack with 12 DSUB connectors would be ideally.

Also thinking about adding some digital control to it, either with raspberry pi or hacking some old broadcast switch cards. Making it more SSL like (like the routing in the Matrix and AWS consoles) a sort of 32×32x32 version of the discontinued SSL X-patch.

Anyone done something similar or have any tips or ideas on how to approach this?

« Last Edit: July 24, 2019, 12:45:50 PM by Zebra_PD »
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se


Re: 32 in/out routing in a 19" rack?
« Reply #1 on: July 24, 2019, 11:25:30 AM »
Why not use two Motu 16A?

Zebra_PD

Re: 32 in/out routing in a 19" rack?
« Reply #2 on: July 24, 2019, 12:12:28 PM »
Why not use two Motu 16A?

Only 16 analog IO on the motu so buying another Orio 32 would be more practical if going the full digital route.

The reason for going for a analog routing solution is to keep DA/AD converting to a minimum.
« Last Edit: July 24, 2019, 12:46:26 PM by Zebra_PD »
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se

Zebra_PD

Re: 96 in/out routing in a 19" rack?
« Reply #3 on: July 24, 2019, 12:17:16 PM »
But looking up the specs on the motu made me think since it had AVD support.

There most have been a time in say late 90s when broadcast was still analog but usually digital controlled when the sort of thing I'm looking to build perhaps existed in the broadcast world?

"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se

Zebra_PD

Re: 96 in/out routing in a 19" rack?
« Reply #4 on: July 24, 2019, 12:32:34 PM »
Well it seems that Flock Audio have built a analog patchbay with digital control. But buying one or perhaps two of those for about 3k €  each is at the moment to much... so the search for a more DIY approach continues.

https://www.flockaudio.com/

« Last Edit: July 24, 2019, 12:47:27 PM by Zebra_PD »
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se

moamps

Re: 96 in/out routing in a 19" rack?
« Reply #5 on: July 24, 2019, 03:17:32 PM »
There most have been a time in say late 90s when broadcast was still analog but usually digital controlled when the sort of thing I'm looking to build perhaps existed in the broadcast world?

Leitch Panacea may be a good choice.
for example, 32stereo to 16 stereo for 200€
https://www.ebay.de/itm/LEITCH-PANACEA-P-32-x-16-A2/173887514078?hash=item287c80e5de:g:09AAAOSwGwFcnnQy

ruffrecords

Re: 96 in/out routing in a 19" rack?
« Reply #6 on: July 24, 2019, 03:19:53 PM »
There most have been a time in say late 90s when broadcast was still analog but usually digital controlled when the sort of thing I'm looking to build perhaps existed in the broadcast world?
I am sure they did. Fernseh used to make huge switches for radio and TV. Back in the 70s at Neve we did a large talkback system for RTE in Dublin. They had a huge Fernseh  video switcher and we used spare contacts on these realys to tell use where to route the talkback.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Zebra_PD

Re: 96 in/out routing in a 19" rack?
« Reply #7 on: July 24, 2019, 04:07:33 PM »
Leitch Panacea may be a good choice.
for example, 32stereo to 16 stereo for 200€
https://www.ebay.de/itm/LEITCH-PANACEA-P-32-x-16-A2/173887514078?hash=item287c80e5de:g:09AAAOSwGwFcnnQy

Not a bad suggestion, would work for line level switching and prob possible to find or program a software that still support it. Might be half the solution for the mixing part of things if I'm able to integrate one of these in the overall solution.

Would still need to build a separate passive switch that support phantom power for tracking. Or keep one patchbay.

Guess there is a reason that separate phantom power boxes are used in broadcasting...
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se

Zebra_PD

Re: 96 in/out routing in a 19" rack?
« Reply #8 on: July 24, 2019, 04:43:53 PM »
I am sure they did. Fernseh used to make huge switches for radio and TV. Back in the 70s at Neve we did a large talkback system for RTE in Dublin. They had a huge Fernseh  video switcher and we used spare contacts on these realys to tell use where to route the talkback.

Cheers

Ian

Thx Ian! Perhaps there is some Fernsehr or similar gear in a broadcast warehouse out there that have survived the 90s race to digital that would be a good starting point and cheap source for parts.
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se

john12ax7

Re: 96 in/out routing in a 19" rack?
« Reply #9 on: July 24, 2019, 05:29:14 PM »
You can look into various crosspoint switches like AD75019. What is lacking,  even from commercial units,  is what is the real world audio performance of these vs a traditional patchbay.


Brian Roth

Re: 96 in/out routing in a 19" rack?
« Reply #10 on: July 24, 2019, 06:34:33 PM »
I remember "back in the day" companies making video/audio crosspoint systems for TV stations and video production studios.  Brands included Grass Valley, Sierra, and Sigma.  As John alluded (above), the audio quality was OK for the applications, but not what I'd call SOTA.

Bri
Brian Roth Technical Services
Salina Kansas, home of the best vinyl on the planet!

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iampoor1

Re: 96 in/out routing in a 19" rack?
« Reply #11 on: July 24, 2019, 06:37:23 PM »
It could be done with ~32768 relays.   ;D

squarewave

Re: 96 in/out routing in a 19" rack?
« Reply #12 on: July 24, 2019, 07:11:17 PM »
It could be done with ~32768 relays.   ;D
I assume you're kidding of course. Even a crosspoint swich would use 96x96 = 9216 switches. But in practice you would not be connecting multiple inputs to the same output because that would be mixing which would require mix resistors and amps which is another project entirely (AD75019 has an Ron of 200+ ohms so mix resistors are problematic). So if you just want an output to select one source it only takes N-1 relays to select one of N sources because you can just cascade 1 into 2 into 4 and so on. So, for example, an 8 input and 8 output switch where each output selects one of the 8 sources, that would take (8-1)*8 = 56 relays. Or 56 analog switches but I think I would just use 56 relays w/ 7 L9823 relay drivers and then you don't need IO buffering and dual pole makes it balanced whereas with an analog switch you probably would need to de-balance, switch and then re-balance. Just thinkin' out loud though.
« Last Edit: July 24, 2019, 07:47:25 PM by squarewave »

Zebra_PD

Re: 96 in/out routing in a 19" rack?
« Reply #13 on: July 26, 2019, 10:07:55 AM »
I assume you're kidding of course. Even a crosspoint swich would use 96x96 = 9216 switches. But in practice you would not be connecting multiple inputs to the same output because that would be mixing which would require mix resistors and amps which is another project entirely (AD75019 has an Ron of 200+ ohms so mix resistors are problematic). So if you just want an output to select one source it only takes N-1 relays to select one of N sources because you can just cascade 1 into 2 into 4 and so on. So, for example, an 8 input and 8 output switch where each output selects one of the 8 sources, that would take (8-1)*8 = 56 relays. Or 56 analog switches but I think I would just use 56 relays w/ 7 L9823 relay drivers and then you don't need IO buffering and dual pole makes it balanced whereas with an analog switch you probably would need to de-balance, switch and then re-balance. Just thinkin' out loud though.

Good info and points!!

I'll try to read up on relays and switches.

Also try to figure out how Flock Audio have solved it all...
"The looks is half the sound"
----------------------------------------------------------
My company:
www.zebrastudios.se


 

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