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Neumann Kh120ii + H750 to AES DB25 connectivity advice needed please!

Joined
Aug 24, 2024
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Hi guys,

I am about to purchase these + KH750 and MA1 mic and thanks to Amir for the original review and tests! Was great to read through.
I have searched for all relevant terms but had no luck so thought I’d ask as I’m really struggling to establish how I will connect my interface (Metric Halo ULN-8 which uses digital out on AES DB25/DSub) to this system of 2x120ii’s + KH750 for use with a full range MA1 calibration.

I want to make all connections digitally, to avoid unnecessary AD/DA conversion, and so analog connectivity isn’t suitable for me.

As pictured in the attachment to this post from the KH750 manual, when wanting to make all connections digital; it seems to suggest (but tbh I find this diagram a little unclear) that you go digitally from interface (AES on DB25/D-Sub, into SPDIF on the first KH120ii and then from the first KH120ii to the second KH120ii I would use a standard SPDIF RCA cable, and then finally I would go from SPDIF out of the KH120ii into the AES on BNC on the KH750

Firstly to do this way, I would need some way of level and impedance matching from AES on DB25 (110ohm) to the 75ohm SPDIF input on the KH120ii

And then I would also need a way of making sure the final connection is also correct:

KH120ii SPDIF out to the KH750’s AES BNC input (but my understanding this shouldn’t be difficult as both have 75ohm impedance and no level matching issues).

( This has taken a long time to research as you can probably tell!)

Now I am aware that it is possible to go into the subwoofer first, which in someways is a lot easier as my interface has AES on DB25 - from there Neutrik level and impedance matching adaptor (Neutrik NADIT BNC-F - which coverts the DB25 AES
  • Input: 3-Pin XLR jack 110 Ohm
To:
  • Output: Female BNC 75 Ohm
From there you take a 75 Ohm BNC cable from the adaptor into the KH750 subwoofers’s AES IN (on BNC) and then from there I would take a BNC to RCA cable from the KH750 AES OUT to KH120ii SPDIF IN and then finally a RCA cable from the first 120ii to the second - by connecting SPDIF out to SPDIF in on the other speaker.

This method I’ve been assured will work by my dealer. However the reason I’m wanting to explore how I can go *into the KH120ii’s first* from my interface and the subwoofer last; is because firstly this is what the KH750 manual *seems* to suggest in the attached diagram. And secondly Neumann told me the following when enquiring as to which is the best way for a fully digital signal path of connections

the order of the digital cabling is variable. We recommend the sequence as in the manual, as it works most reliably from a latency point of view.’

And finally I had asked which guaranteed the lowest latency (my studio is for tracking the majority of the time and is heavily complex - so reducing 1ms or even less, just by changing the way this system is connected is absolutely a question I want to make sure I answer correctly to ensure I have the lowest possible latency (which I know has to be fully digital to avoid additional latency from unnecessary AD/DA in the speakers themselves)

So the language of ‘most reliably from a latency point of view’ whilst I find somewhat confusing and have extrapolated that it means that the manual diagram is the lowest latency (mentioned here as ‘most reliable’ by Neumann).

So with this in mind - I’m back querying how best to ensure I have the exact cabling needed to go:

INTERFACE AES DB25 OUT to KH120ii SPDIF IN
Then
KH120ii SPDIF out to SPDIF in of other KH120ii
Then
KH120ii SPDIF out to KH750 AES BNC IN

To further complicate things - the KH120ii manual seems to contradict the written advice and pictured advice from manual for fully digital connectivity by saying the following:

If the signal source is based on internal digital signal processing, it is recommended that you choose a digital connection between the signal source and the loudspeaker . This eliminates the need for additional signal conversion from digital to analog in the source and from analog to digital in the loudspeaker . This also applies if you are connecting to an upstream DSP subwoofer (e .g . KH 750 DSP) . This should be connected to the loudspeakers via its digital output

So hopefully it’s clear why I’m not finding this exactly crystal clear as to which approach to take to ensure the lowest possible latency, and correct cabling/impedance+level matching.

Thanks so much for reading this, and thank you very much in advance for any suggestions or help here in making me finally be able to purchase knowing I’ll have everything needed and planned correctly.
 

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Hi guys,

I am about to purchase these + KH750 and MA1 mic and thanks to Amir for the original review and tests! Was great to read through.
I have searched for all relevant terms but had no luck so thought I’d ask as I’m really struggling to establish how I will connect my interface (Metric Halo ULN-8 which uses digital out on AES DB25/DSub) to this system of 2x120ii’s + KH750 for use with a full range MA1 calibration.

I want to make all connections digitally, to avoid unnecessary AD/DA conversion, and so analog connectivity isn’t suitable for me.

As pictured in the attachment to this post from the KH750 manual, when wanting to make all connections digital; it seems to suggest (but tbh I find this diagram a little unclear) that you go digitally from interface (AES on DB25/D-Sub, into SPDIF on the first KH120ii and then from the first KH120ii to the second KH120ii I would use a standard SPDIF RCA cable, and then finally I would go from SPDIF out of the KH120ii into the AES on BNC on the KH750

Firstly to do this way, I would need some way of level and impedance matching from AES on DB25 (110ohm) to the 75ohm SPDIF input on the KH120ii

And then I would also need a way of making sure the final connection is also correct:

KH120ii SPDIF out to the KH750’s AES BNC input (but my understanding this shouldn’t be difficult as both have 75ohm impedance and no level matching issues).

( This has taken a long time to research as you can probably tell!)

Now I am aware that it is possible to go into the subwoofer first, which in someways is a lot easier as my interface has AES on DB25 - from there Neutrik level and impedance matching adaptor (Neutrik NADIT BNC-F - which coverts the DB25 AES
  • Input: 3-Pin XLR jack 110 Ohm
To:
  • Output: Female BNC 75 Ohm
From there you take a 75 Ohm BNC cable from the adaptor into the KH750 subwoofers’s AES IN (on BNC) and then from there I would take a BNC to RCA cable from the KH750 AES OUT to KH120ii SPDIF IN and then finally a RCA cable from the first 120ii to the second - by connecting SPDIF out to SPDIF in on the other speaker.

This method I’ve been assured will work by my dealer. However the reason I’m wanting to explore how I can go *into the KH120ii’s first* from my interface and the subwoofer last; is because firstly this is what the KH750 manual *seems* to suggest in the attached diagram. And secondly Neumann told me the following when enquiring as to which is the best way for a fully digital signal path of connections

the order of the digital cabling is variable. We recommend the sequence as in the manual, as it works most reliably from a latency point of view.’

And finally I had asked which guaranteed the lowest latency (my studio is for tracking the majority of the time and is heavily complex - so reducing 1ms or even less, just by changing the way this system is connected is absolutely a question I want to make sure I answer correctly to ensure I have the lowest possible latency (which I know has to be fully digital to avoid additional latency from unnecessary AD/DA in the speakers themselves)

So the language of ‘most reliably from a latency point of view’ whilst I find somewhat confusing and have extrapolated that it means that the manual diagram is the lowest latency (mentioned here as ‘most reliable’ by Neumann).

So with this in mind - I’m back querying how best to ensure I have the exact cabling needed to go:

INTERFACE AES DB25 OUT to KH120ii SPDIF IN
Then
KH120ii SPDIF out to SPDIF in of other KH120ii
Then
KH120ii SPDIF out to KH750 AES BNC IN

To further complicate things - the KH120ii manual seems to contradict the written advice and pictured advice from manual for fully digital connectivity by saying the following:

If the signal source is based on internal digital signal processing, it is recommended that you choose a digital connection between the signal source and the loudspeaker . This eliminates the need for additional signal conversion from digital to analog in the source and from analog to digital in the loudspeaker . This also applies if you are connecting to an upstream DSP subwoofer (e .g . KH 750 DSP) . This should be connected to the loudspeakers via its digital output

So hopefully it’s clear why I’m not finding this exactly crystal clear as to which approach to take to ensure the lowest possible latency, and correct cabling/impedance+level matching.

Thanks so much for reading this, and thank you very much in advance for any suggestions or help here in making me finally be able to purchase knowing I’ll have everything needed and planned correctly.
Your connection seems pretty solid, but at the time of kh750 dsp sub release there was no dsp based kh120 speakers , the kh120 II's manual are updated ones considering this I would follow their guide to achieve lowest possible latency on digital signal path. ( also I would ditch the db25 and go aes67 version and a interface that supports it like Neumann MT48 to lower latency even further )
 
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