TOPIC:

Dear All,

It took us a bit of while to help one of customer to troubleshoot his system and we wanted to make sure we would share this info with everybody!
The symptoms were as follow from an Oppo player (can happen to any player actually).
- CD disc = > Audio OK
- DVD disc = > Audio not working
- Bluray disc => Audio OK..

Little to say that we were intrigued.. Thanks to our HDMI logging app (and the great patience of our customer), we were able to troubleshoot this issue which was related to video resolution. Here is a bit of an explanation so everybody understand.

NanoAVR is designed to output 8 channels of audio at 96kHz but what's important to remember is that there is a relationship between the resolution you choose (e.g. 480/720/1080) and the maximum amount of channels/sample rate allowed under HDMI standard. Here they are:
- A resolution of 1080p can carry 8 channels of audio at 192kHz
- A resolution of 480p can carry 8 ch at 48k (i.e. only 4 ch at 96k) , i,e. nanoAVR can only support 4 ch at 96k.

Based on our logs, this blueray player was configured to carry 480i so the issue was basically not enough throughput to carry 8ch @ 96kHz. Simply changing the Bluray player to be set to 1080 did the trick. Audio was playing for all media.

Quoting p.60 – 61 of the Oppo BDP-93 manua (similar setup can be read from your player).

“If you use HDMI to connect audio to an HDMI A/V receiver or audio processor, it is important that you choose 720p or higher HDMI output resolution when playing high resolution audio content (DVD-Audio, SACD, Dolby TrueHD and DTS-HD Master Audio). According to the HDMI specification, the bandwidth available for audio is proportional to the total bandwidth used by video. At 480p/576p resolution, the HDMI specification can only support 2 channels of audio with high sample rate (up to 192kHz), or 8 channels of audio with standard sample rate (up to 48kHz). If you play high resolution audio content at the 480p/576p resolution, you may get reduced audio resolution, incomplete audio channels, or even no audio/video output at all. Choosing a higher output resolution such as 720p or above allows enough bandwidth for all high sample rate audio channels.”

Hoping it helps you all and have fun with your setup!

DevTeam

Do I understand correctly that the nanoAVR DL, when running only two channels, could work at an internal sample rate above 48kHz, at 96 or 192 kHz?

tcsemp wrote:

Do I understand correctly that the nanoAVR DL, when running only two channels, could work at an internal sample rate above 48kHz, at 96 or 192 kHz?

I'm pretty sure nanoAVR DL is fixed at an internal rate of 48 KHz regardless of the number of channels in use. nanoAVR HD runs at 96 KHz internally.

-- Jim

Thank you very much, Jim. I wonder how useful the nanoAVR DL,is if the hi-rez inputs are squeezed through the 48 kHz bottleneck. My trusty old Behringer SRC/DEQ combo (SPDIF in, SPDIF out) permits room/speaker equalization @ 24/96 level. Can the nanoAVR DL, match the performance of a Behringer DEQ tuned to deliver a perfect sine wave?

[ Deleted by Jim: Incorrect info ]

Dirac Live is a completely different animal to IIR-based units. For 24/96 operation and SPDIF I/O, use the DDRC-22D.

Thank you again, Jim.

Here is some background on the old Behringer DEQ: With 32 bands of graphic EQ per channel plus a 10 band parametric EQ per channel it permits fine tuning the frequency response. As Behringer offers only a crude "automatic" measurement procedure, I am using a mic (calibrated with another Behringer DEQ only for compensating the mic's response). The mic's speaker/room response to test tones from pink noise to sinus is shown on a third Behringer DEQ. To achieve the desired linear frequency response on the third DEQ all I need to do is fiddle with the linear and parametric EQs of the first DEQ.

This, of course, yields only a rough approximation which has to be modified by ear. For this I use a Stax Lambda Pro headset calibrated with the mic inserted in ear cavity and response-corrected by a fourth Behringer DEQ. As test signals I use speech and selected music. The A-B comparison between headset sound and speaker sound in the given room is a time consuming approach (and a good training for the ear) but yields much better results than simple microphone-based measurements..

The DEQ's performance can be tweaked to improve its sinus wave reproduction by following closely the advice given in

www.icycolors.com/nu9n/deq2496.html -- " NU9N - Behringer DEQ-2496 Initial Setup for SSB eSSB Hi-fi Audio"

Cheers,
tcsemp