• From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Topic: HDSPe MADI analog out

The analog out from this card may occasionally be required to provide a mix to a monitoring or recording device with balanced input.  (Even maybe the analog input to the co-located AIO card).

I note that the spec says output impedance (unbalanced) is 75 ohms.  I am inclined to make up a cable TRS to 2xXLR for balanced connection using 'electronic balancing' resistors pin 3 to ground.  For best effect these should be identical to the single ended output impedance.

Could you please confirm that the output impedance is an 'exact' 75 ohms (defined by a resistor ?5%) or a 'nominal' impedance (if so what is it)?  I expect a 75 ohm balancing resistor is close enough for practical purposes but I just thought I'd check.



ps.  Next time, how about making the monitoring output digital - AES or SPDIF?  Or allow TotalMix to access both devices in the one screen?  Having to go down to analog and back up again to have a MADI TotalMix output available for live use is not elegant, IMHO.

De gustibus - et sonus - non est disputandum

2 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
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Re: HDSPe MADI analog out

75 Ohms is correct. The last part (ps.) I do not understand.

Regards
Matthias Carstens
RME

MC's Website

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Re: HDSPe MADI analog out

Thanks for the confirmation.

As for the ps, it is probably rather specific to my configuration (MADI and AIO working together for live broadcast), and perhaps best discussed in PM.  (Or if you visit SMPTE in Sydney in July?  Can't make BroadcastAsia this year - in St Petersburg at the time.)

De gustibus - et sonus - non est disputandum
  • Registered: 2009-03-02
  • Posts: 80

Re: HDSPe MADI analog out

I think he means that he has a madi card and an aio card and he wishes that he could route signal between them because he needs to send a mix from the madi card to the aio card, so he is looping out the spare analog out.  He wishes that you could simply route some outs of the madi card to the aio.

MC, correct me if I am wrong, but the architecture of the cards limits this because the mixing is actually preformed on the card, which means that each card is unaware of any other card.

5 Reply by MC

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Re: HDSPe MADI analog out

You are correct.

Regards
Matthias Carstens
RME

MC's Website

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Re: HDSPe MADI analog out

Excellently summarised, and yes I understand there is currently no mechanism for communication between the DSPs on each card.  (Always possible but complicated.)

Apart from circulating the mix through an application such as REAPER (a reasonable but not preferred compromise) the other purely digital solution could be a digital monitoring out (AES or SPDIF) from the MADI card which can be looped into the AIO.   (Is an AES line driver chip cheaper than a DAC and analog line driver?)

The fall-back is to loop the MADI headphone out to the AIO.  This is a bit of a pity because otherwise we can have one only analog-digital conversion (from the mic preamps in the DigiCo stage box) through the studio to the transmitter.   Last week we had such a connection when we used the DigiCo desk to mix a live broadcast - absolutely pristine sound.

De gustibus - et sonus - non est disputandum
  • From: Italy
  • Registered: 2007-05-06
  • Posts: 137

Re: HDSPe MADI analog out

I also want make a cable for connect monitor to HDSPe MADI analog OUT.

I need a 75 ohms cable, really ? Make a very good  Y cable in not easy. I've see Peacock Sommer Cable but is 110 ohms. Waht cable I need for make a very good balanced Y cable, 75 ohms ?

8 Reply by MC

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Re: HDSPe MADI analog out

An analog output has no 'impedance' to match, and this one is not balanced either...

Regards
Matthias Carstens
RME

MC's Website