MADI Transmitter

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
illusionxx said:

Last year I had my head inside a few of the Euphonix 24 ch AD / DA
racks which all had MADI. Unfortunately we were not interested in
that aspect of the converters and didn't pay any attention to what
was driving the OP's or receiving the IP's.

My -guess- is there are no chips specifically for this application
as there are AES/SPDIF... that's just a guess.

There -may- be some info in this paper.

http://www.aes.org/e-lib/browse.cfm?elib=5340

Why do I get the feeling John Westlake might know something
about this.

Sorry can't be of any more help. I'd be interested if you do turn
something up.

Cheers,

Terry
 
illusionxx said:
Thx for your answers. Looks like i will have to use a FPGA, too. Flexibility is an good argument although i`m not eager to lern VHDL.
I will report should i come across any interesting chip.

Terry you don`t have the mentioned paper to share?

illusionxx

Sorry, no, I would have offered it if I did.

Just out of interest, what is your application?

Cheers,

Terry
 
With SonyOxford's SuperMAC, which has recently been standardised by the AES as AES50, there's already a successor of MADI, so it doesn't really make sense to develop a multicore system based on this rather outdated standard.

The future of digital multicore systems will be Ethernet, but with thousands of vendor-specific protocols. :mad:

@illusionxx, you have PM
Holger
 
Terry,

thx for the links but i can`t wait until the cirrus chips are available.


Holger,

the AES50 standard sounds promising, but i haven`t red their paper regarding this toppic yet. Maybe i`ll have the time to read it this evening.

If it makes sense to develop a multicore on MADI basis depends on the functionality expected from the device. AES50 features 32 channels in both direction while AES10 offers 64 channels in one direction. If the extended network capabilities of AES50 are not required MADI will suffice. On the other hand why bother about MADI transmission hardwear if 64 channels are not needed and AES50 uses ethernet`s physical layer.
The third possibility would be to develop my own transmission protocol adapted to the needs of my specific multicore system.

illusionxx
 
AES50 supports more channels, up to 48 in each direction, depending on the sample rate, plus 5MBit of auxiliary data.

As I have to deal with several multichannel audio interfaces I'm a little bit allergic to another proprietary standard. AES50 is an open one and seems to be good enough for a simple digital multicore where extended routing capabilities are not needed. Additionally it makes sense if you could plug your multicore directly into a digital mixing desk, so it would be better to use a supported standard.

Do you also have to develop A/D also or is it "just" the transmission of digital audio signals from stage? If you have A/D converters on stage you need a way to control them, which is not possible with MADI, as transmission here is unidirectional.

I'd stick to a already established standard. If you want to avoid FPGA you could use the SuperMAC chip or one of Cirrus' Cobranet chips. If you need some additional logic in your design, take a FPGA, get a license from EtherSound or SuperMAC and do everything in the FPGA. But licenses are quite expensive, especially for EtherSound.
 
illusionxx said:

On the other hand why bother about MADI transmission hardwear if 64 channels are not needed and AES50 uses ethernet`s physical layer.
The third possibility would be to develop my own transmission protocol adapted to the needs of my specific multicore system.

illusionxx


You could consider AES47 as a compromise position. It is ATM based and offers 8 duplex 24/192 channels over a single CAT5 cable.
 
Klark Teknik, and therewith the whole Bosch/Telex group is the new owner of SuperMAC. See the corresponding press release

It is just comprehensible that they want to have the control over a core component of the Midas XL8, but I personally think that this is not a good basis for the further spread of AES50. If you're in the pro-audio business you can license technology from Sony, but you will have reservations towards signing such an agreement with one of the big players and potential competitor.

I hope AES50 will develop further towards a common audio networking standard, but IMHO the premises for that are not the best.
 
Thanks,

I just read the press release and I confess I am more than a little confused. What exactly did Klark-technic buy? The underlying protocol is in the public domain??? They bought rights to the extensions?? Whoopee ...

I've got to believe that the Midas people are confused (annoyed??) as well.

Are there other protocols out there? I've been off doing other things and haven't stayed current. I am currently interested in exploring low latency audio on ethernet. Thank you for your time and thoughts.
 
Carl,

I don't think that Midas is confused, they belong to the same group since Bosch has bought Telex (=ElectroVoice, Dynacord, Midas, Klark Teknik and RTS) in June 2006. ;)

Klark has bought Sony's implementation of AES50, called SuperMAC. Sony has invented this protocol which has then been standardized by the AES. Of course you can theoretically design your own implementation based on this standard, but this will be a quite complex task. Additionally there might be patents from Sony used in the implementation you would then violate.

There are quite a few protocols, but most of them are proprietary and therefore out of reach for the DIYer. The only protocol without licensing issues I know of is Cirrus Logic's CobraNet. You can simply buy their chips and use them. Everything else becomes difficult.

What are you planning to do exactly?
 
Geez ...

I've been away too long. I hadn't realized that Midas was a Telex company. That explains alot then.

I was toying with the idea of doing a whole house, multi zone audio implementation over ethernet. My intent would be to craft simple receivers (preferably using a PIC) with good DACs at active loudspeakers. Each loudspeaker group (zone??) would be managed from a desktop computer acting as controller sitting on the network.

It sounded like a fun project to bring my skills current. I've seen recent examples from Meridian and then there is the whole house NetStream thing. I'd like to do something interesting and just put it out there for others to use and grow.

As I remember (it has been a while) but doesn't Cobranet have latency issues? I confess, I don't remember much ...
 
Cobranet has a higher latency compared to other solutions like EtherSound or AES50 which is the price you have to pay for full ethernet compatibility. Only the brand new Dante from Audinate claims to combine full Ethernet compatibility and low latency, but I didn't see it working so far.

But for your application the minimum latency of 1,3ms of CN would be no problem at all, AD/DA conversion alone will probably take longer.

You can even think of using a software based solution (e.g. Linux on a cheap ethernet enabled evaluation board like the Atmel NGW100). I don't know whether a PIC can handle this task.
 
The PIC24 series run at 40 MIPS and cost as little as $1.99 (volume pricing). It should be capable.

However that Atmel NGW100 eval board does look especially interesting. Mouser (US distributor) has them in stock for only $73.15. I see that the development tools are free as well. Thanks for the tip! I think that I will order up an eval board.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.