Dolby Atmos and REW

SeanP

New Member
Thread Starter
Joined
Jul 31, 2017
Messages
7
My AV System  
Preamp, Processor or Receiver
AVM60
Main Amp
Odyssey Stratos Stereo
Additional Amp
MM9000 MM7055
Universal / Blu-ray / CD Player
203 oppo
Front Speakers
Revel F52
Center Channel Speaker
Revel F32
Surround Speakers
Revel M106
Surround Back Speakers
Revel M106
Front Height Speakers
Revel C763L
Rear Height Speakers
Revel C763L
Subwoofers
LMF-1 EX, VTF-3 MK5
Video Display Device
LG OLED65G6P
Remote Control
Logitech Elite
Other Equipment
mede8er med1000x3d
ok I got the hdmi working but is there away of testing the 0.0.4 over head channels in REW short of switching the overheads output on the preamp to the surround inputs on the amp?
 

Matthew J Poes

Staff Writer
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Joined
Oct 18, 2017
Messages
1,830
I don't believe so. REW is sending a signal to each discrete via PCM, but there is no way to send a signal to the effect channels through PCM. You would have to encode the test tones into ATMOS and then send the signals via HDMI to an ATMOS decoder. You will have to switch inputs I'm afraid. This shouldn't be an overly important thing to measure so I wouldn't worry too much about it. Maybe go through the effort once and then don't worry so much.
 

SeanP

New Member
Thread Starter
Joined
Jul 31, 2017
Messages
7
My AV System  
Preamp, Processor or Receiver
AVM60
Main Amp
Odyssey Stratos Stereo
Additional Amp
MM9000 MM7055
Universal / Blu-ray / CD Player
203 oppo
Front Speakers
Revel F52
Center Channel Speaker
Revel F32
Surround Speakers
Revel M106
Surround Back Speakers
Revel M106
Front Height Speakers
Revel C763L
Rear Height Speakers
Revel C763L
Subwoofers
LMF-1 EX, VTF-3 MK5
Video Display Device
LG OLED65G6P
Remote Control
Logitech Elite
Other Equipment
mede8er med1000x3d

TheSound

New Member
Joined
Apr 24, 2018
Messages
3
I don't believe so. REW is sending a signal to each discrete via PCM, but there is no way to send a signal to the effect channels through PCM. You would have to encode the test tones into ATMOS and then send the signals via HDMI to an ATMOS decoder. You will have to switch inputs I'm afraid. This shouldn't be an overly important thing to measure so I wouldn't worry too much about it. Maybe go through the effort once and then don't worry so much.
Hi Matthew,

i am struggling a bit on the the same item... If i switch inputs, the measurement in REW will show a frequency curve, that is influenced by the audyssey or dirac AVR measurement set filters (in case its the case, that this will be used in normal operation).

E.G., if i cannot reach with a 5.1 soundcard the surround back right and plug this on the surround right, i will measure the SBR with the audyssey filter for the SR. And i do not know, how big the influence is. With a 7.1 soundcard it should be solved, but for all ceiling speakers it cant be solved. Are there any studies that show, that the effect from the audyssey (e.g.) filters is neglectable?

rgds, Holger
 

Matthew J Poes

Staff Writer
Staff member
Joined
Oct 18, 2017
Messages
1,830
Hi Matthew,

i am struggling a bit on the the same item... If i switch inputs, the measurement in REW will show a frequency curve, that is influenced by the audyssey or dirac AVR measurement set filters (in case its the case, that this will be used in normal operation).

E.G., if i cannot reach with a 5.1 soundcard the surround back right and plug this on the surround right, i will measure the SBR with the audyssey filter for the SR. And i do not know, how big the influence is. With a 7.1 soundcard it should be solved, but for all ceiling speakers it cant be solved. Are there any studies that show, that the effect from the audyssey (e.g.) filters is neglectable?

rgds, Holger
Are you referring to Audyssey’s upmixer or eq. If the upmixer, then I agree this is not a good way to attempt to measure. It is highly unlikely you will get a discrete measurement of those speakers. If you are referring to the eq, that is on all channels. It’s always impacting your measurements if you do not turn it off.

I am able to measure 8 channels using REW, so I can measure all surround channels.

As for ATMOS, I do not believe it is currently possible to measure the atmos speakers through the atmos channels of the processor without a special test disc, which does not exist. I have looked into authoring it and it’s very expensive. The only atmos mixing software in existence costs quite a bit.

For closed loop systems this is a problem, but for discrete component systems, you can simply temporarily rewire the atmos speakers to another channel and measure in that way. It’s perfectly accurate.
 

TheSound

New Member
Joined
Apr 24, 2018
Messages
3
Hi Matt,

thanks for your response... I am talking about the audyssey room measurement.

I use it on my Marantz SR7010 because i take a lot benefit of the dynamic eq and on some sources also of the dynamic volume (e.g. aTV or youtube) and using it optimises by a filter after room measurement the frequency curve of the different speakers (not beeing transparent at all). But if you use audyssey it is as it is. So without enableing audyssey rewiring on the rew measurings is of course fine.

But after enabling audyssey you would get something different. And measuring with enabled audyssey you get "foreign" filters on the frequency curve and a different situation as measured after wiring back.

The question is just: how big is the failure, especially on ceiling speakers
 

Matthew J Poes

Staff Writer
Staff member
Joined
Oct 18, 2017
Messages
1,830
Hi Matt,

thanks for your response... I am talking about the audyssey room measurement.

I use it on my Marantz SR7010 because i take a lot benefit of the dynamic eq and on some sources also of the dynamic volume (e.g. aTV or youtube) and using it optimises by a filter after room measurement the frequency curve of the different speakers (not beeing transparent at all). But if you use audyssey it is as it is. So without enableing audyssey rewiring on the rew measurings is of course fine.

But after enabling audyssey you would get something different. And measuring with enabled audyssey you get "foreign" filters on the frequency curve and a different situation as measured after wiring back.

The question is just: how big is the failure, especially on ceiling speakers
No easy way of knowing. You really don’t want to measure through dynamic eq modes. They change the eq based on the level of the content. The test is very artificial. That should be judged based on sound alone. Do you like it?

As for measuring the eq filters of the atmos channels with Audyssey enabled, unless I’ve missed something big, you can’t measure that right now. There is not a way to send a test tone to those signals through something like REW.

@John Mulcahy can confirm, but it is my understanding that no software can send a signal with the meta-data to go to an atmos channel without purchasing a license through Dolby. In addition, my understanding of how ATMOS works would make it hard to do. For a contract I have with a manufacturer I actually looked into this. I looked at having a custom test disc authored with specific test tones and sweeps. The company I talked to specializes in ATMOS and DYS:X authoring and has the software needed. They told me it is not possible to send discrete test tones to specific atmos speakers. You send it to a geometric position in hemispherical space. The processor then decides which set of speakers get the sound with what level and eq. That makes measuring through ATMOS nearly impossible.

A better solution might be to see if the receiver has built in pink noise that can be sent to discrete atmos channels and using the RTA mode. This may or may not work depending on the kind of pink noise built in and how it’s piped through the processing chain. They might bypass the Audyssey eq filters for example. They may also use a weighted pink noise that gives an artificial response shape. I wouldn’t know without measuring myself.
 
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