[AudioI] Isolated Audioinjector Question

[David Klann]

Hi Matt,

Thanks for your reply!

On 12/30/20 6:58 PM, Matt via People wrote:
> Hi,
> 
> Great to hear that it sounds good.
> 
> Below are my output and input alsamixer screendshots for the Isolated 
> and Pro. soundcards. The Master output gain controls the level on the 
> output. The input has no gain in the audio codec.
> 

My views with alsamixer look just like your screenshots.

> The XLR preamplifier has 13 dB gain on the output (boosting the full 
> scale level to around +-10V). The input gain is -12.8 dB which takes a 
> high voltage XLR level and drops it around 4.4 times.
> 
> Is it possible that the signal being sent to the sound card is not loud 
> enough, so that when the XLR preamplifier drops the level, it reduces it 
> too much ?
> 

Thinking about it, this is most likely the case. The ARC-8 Program 
outputs are +4dBu balanced (with XLR connectors). I probably need a 
"distribution amp" between the board and the Isolated Soundcard. I was 
hoping that the preamps on the XLR board would bring the levels up 
enough for a direct connection from the board.

> I'm not familiar with the Arrakis ARC-8 radio mixing console. Can you 
> please explain a little about its output connections and signal levels ?
> 

The ARC-8 manual claims that the maximum output is +23dBu balanced. I'm 
not sure how that spec relates to the statement that the Program output 
is +4dBu balanced...

Thanks for confirming that there is no gain control on the input side.

Best regards,

   ~David Klann


> 
> On 31/12/20 10:24 am, David Klann via People wrote:
>> I recently bought an Isolated Soundcard with the XLR Preamplifier. It's
>> working great (worked fine right out of the box), and it sounds great!
>>
>> Using alsamixer(1), I see a gain control for the inputs, but not for the
>> Capture port(s). Is there an on-board way to control the output gain?
>>
>> My current audio source is the Program output on an Arrakis ARC-8 radio
>> mixing console. I'm using the Audioinjector to receive the analog audio
>> and Liquidsoap on the Pi to encode the audio and send it to a stream
>> server. Listening to the stream, the levels seem kind of low to me.
>>
>> Thanks for your thoughts.
>>
>>     ~David Klann
>>
> --
> Checkout the community email list :
> https://lists.audioinjector.net/mailman/listinfo/people
> 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_0x745A93D6286EC7BC.asc
Type: application/pgp-keys
Size: 49289 bytes
Desc: not available
URL: <https://lists.audioinjector.net/pipermail/people/attachments/20201231/8507eda9/attachment-0001.key>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 243 bytes
Desc: not available
URL: <https://lists.audioinjector.net/pipermail/people/attachments/20201231/8507eda9/attachment-0001.sig>