Film-Tech Forum ARCHIVE: Blu-ray volume

This is topic Blu-ray volume - DMA8plus/CP650 in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Andreas Borman (Member # 9014) on 09-29-2016, 09:28 AM:

Hi guys,

Anyone tried playing Blu-ray disks and found a way to get sufficient volume level? Compared to playing DCP the level is so low that setting the CP650 to level 10 is not nearly sufficient.
I'm using the digital coax AES3 input on the Dolby DMA8plus. I've tried connecting the analog stereo output signal from the blu-ray as a non-sync input on the CP650 too. Also low levels.

Any ideas? Thanks in advance.

Posted by Scott Norwood (Member # 30) on 09-29-2016, 01:24 PM:

Does the player have some sort of internal volume control? What type of player is it? I know lots of venues that use Oppo players connected to the external 6-channel inputs on CP650s that have no issues. The DMA8 works well, too, but some Blu-Rays have no Dolby track or default to a DTS track that the DMA8 cannot decode.

The Oppo has some settings for "speaker type" and such that can affect the sound output. Perhaps yours has something similar?

Posted by Jim Cassedy (Member # 4115) on 09-29-2016, 01:26 PM:

Just a few thoughts:

Perhaps you player has a low output, or there is an "output level" control
somewhere in the menus that can boost the output volume?

>Have you tried swapping with another blu-ray player to see if it's low too?<

That being said, I have been to a couple of screening rooms where they've
run the (analog) outputs of the blu-ray through a pre-amp before sending
them to the CP-650.

First thing I'd do is try another blu-ray deck & see if its' volume is low too.

Posted by Carsten Kurz (Member # 5396) on 09-29-2016, 05:04 PM:

If you use a digital output, there is usually no volume control on a DVD/BluRay player, as you normally pass digital encoded data in bitstream format.

However, some players actually do fiddle with the volumes, even AC3 etc., when certain advanced features are activated - like BD+ mixing, 'night mode' (actually a dynamic compressor), etc.
I would go through the BD player setup and check all suspect items. Usually the first thing I do when I setup a player.

I don't know wether DMA8+/CPU deal with incoming AC3 in any special way. You would think they need to establish an internal reference to '7'.

- Carsten

Posted by Sam King (Member # 4029) on 09-29-2016, 06:32 PM:

We used optical toslink into the DMA8+ and added an optical booster, I think from monoprice, to the optical run into the DMA8+, that allowed us to be at a comfortable 6ish on the CP650 fader. Worth a shot?

Posted by Marco Giustini (Member # 4544) on 09-30-2016, 09:39 AM:

optical booster!

Digital sound has a nice roof called 0dBFS. If you clip that you add buckets of distortion! I would stay away from those things.

I would check into the settings, see if there is any volume control. In the end, if a Blu Ray is recorded up to 0dBFS, it will be 0dBFS on a CP650 as well.

I would also try another BD player

Posted by Carsten Kurz (Member # 5396) on 09-30-2016, 05:34 PM:

Optical boosters are just Toslink-Extenders, they don't modify the audio signal level.

What type of player is this?

- Carsten

Posted by Mark Gulbrandsen (Member # 72) on 09-30-2016, 08:49 PM:

The only players that seem to have decent output level are the Oppo's. I have tried every dang BR player out there mostly to no better results.

USL Processors seem to work a little better because they will remember the gain setting for BR, or you can preset it to a fixed level... which is usually all the way up or pretty close to it.

Mark

Posted by John Thomas (Member # 6509) on 09-30-2016, 11:12 PM:

I have only used the original DMA8 but if you can connect to it with your computer you should be able to see all your channel levels live. Low levels on the DMA8 would tell you that the problem is between your bluray player and your DMA8. As was stated already however digital audio is only transmitted at full volume (to put it simply) so this SHOULD not be the problem.

Check your levels on the 650 during playback and make sure you are getting activity on more than just Left and Right. If your bluray player is downmixing to 2ch PCM then make sure your DMA8 has ProLogic enabled to put it "back" into 5.1. Otherwise you're trying to pump all your channels through Left and Right while leaving Center silent, which would make the volume weak.

Likewise if you end up using nonsync, again, make sure you're using NS with ProLogic and SW or else you're not making use of Center. Format 75 I think. You can also adjust your NS level in the 650 software if necessary.

If you are getting levels on all channels on the DMA8plus and they look good in the software you could try a different DB25 cable between the DMA8 and the 650 (under the assumption you're going in through the analog 6ch input). Try plugging into a different house if that is an available option and see if the problem follows.

Posted by Marco Giustini (Member # 4544) on 10-01-2016, 02:51 AM:

Mark,
You do not need to spend an arm and a leg on a blue ray player. Most of them will work just fine.
Blue ray disks are usually mastered at a lower level but that should not be a big deal in the auditorium. I suspect the player is bugged (software update?) Or poorly designed. I'd try another one.
Also, maybe that sound system is calibrated a little low? What's the average volume level films are being played during regular performances?

I suggest you create a pcm 5.1 file with 0dB pink noise and test the outputs. (Watch the volume!!)
Also check for any automatic gain controls (ADR?) And disable that.

Posted by Steve Guttag (Member # 268) on 10-01-2016, 03:50 AM:

The Oppo isn't an arm and a leg. More expensive, yes but also it is rather feature laiden.

Note, we too have found that Blu-ray levels tend to be low/challenging. If your typical DCP volume is 5.5-6.0, your Blu-ray is going to be 7 or higher.

Posted by Gavin Lewarne (Member # 5397) on 10-01-2016, 06:18 AM:

Steve - I haven't found that to be the case at my venue at all.

We typically play our DCPs at around 5 to 5.5 (small auditorium). Our BluRay player is some Sony Consumer grade one. Running SPDIF directly into our CP750 I get approximately the same volumes from it as I do our playback server.

I really like our Sony BR player - its a slightly older model and has every imaginable video and audio output connector, can completely disable any and all sleep / auto-off modes (nice to be able to queue up a disk for playback paused on black with an unlimited amount of time you can leave it there) and can also turn off any and all OSD icons, so when we hit play nothing at all - no icons - no messages - comes up on the screen - it just plays.

It also has a nice DTS downmix to PCM feature so even DTS encoded discs play back in 5.1 on our CP750

Ive messed around with the standard RCA L/R outputs from it into the non-sync input of our 750 as well and with some fine tuning on the CP750 non-sync input level slider, can also achieve almost identical volumes to DCP.