Home Theater Dynamic Range Considerations

I've been thinking how to write a thread to best discuss this topic for a long time now.

After considering it at length, I decided to start with the general topic rather than as a problem of my specific equipment, and how to set it up. We may eventually degenerate into an equipment specific discussion, but I am electing not to begin that way. If it's absolutely necessary, I'll post new thread topics specific to my equipment in other forums, and provide links to them here.

Generally speaking, you should know that I am addressing myself to those with Surround Sound processors such as DSP based Digital Receivers with DTS, Dolby Digital [aka DD5.1, AC3 and Dolby HD] with TOSlink [optical], Coax, or HDMI capability and combinations of same.

* Owners of THX certified systems will find this thread of particular interest as these are in my stable, and may be discussed.

Overview:

With the advent of the Blu-Ray format and it's winning out over HD-DVD - the issue of Dynamic Range in home theater has come to the foreground. In the past couple years, particularly in the U.S. region, fewer and fewer titles have been issued with Dolby Digital compatible sound tracks as the primary [English in my case] track and indeed - DTS HD Master Audio tracks appear to have become the defacto standard.

Moreover - while alternate language sound tracks are often included in Dolby Digital 5.1 [previously known as AC3] the Gods of Blu-Ray never seem to include one in English. Indeed - if they offer one at all it's usually Dolby Surround, a Matrix 2.0 variation.


I have found that DTS has far too much Dynamic range for my liking. I've grown to really despise it for the vast majority of my listening. In my situation, I cannot count the number of evenings it was necessary to "ride the volume control", compensating by 10db or more from scene to scene to be able to hear spoken dialogue one minute and prevent others in the home from being "rattled from their beds" the next - by gunfire, fog horns and other effects sounds.

I am being quite literal here.

This is a constant annoyance and spoils the mood taking me from enjoyment of many a Blu-Ray title to the point where I have abandoned the visual treat of my HD title in favor of the DVD edition, just to be able to listen to the Dolby Digital 5.1 track and make use of the Dynamic Range reduction features it enables in my Surround Receiver.

In pursuing this goal of HD Video and Dynamic Range Reduction, I have played extensively with various methods of attaining less with DTS sources. These include:

• Purchase of a Blu-Ray player with Bitstream DTS->Dolby Digital Re-encode capability
• Use of PCM rather than Bitstream settings
• Enabling / Disabling In-Player "Dynamic Range Control" feature
• HDMI vs Optical Sound conveyance
• Selection of a Receiver with Multiple Dolby Digital listening modes [Low and High "Midnight Theater"]
• THX modes and "Loudness" settings

Recently I've been looking into Dynamic Volume functions of Audyssey but been unable to gain access to these in my equipment, even though I see they are supported. [Apparently they're only enabled after a suitable automatic setup sequence]



So, that's the topic.

• Am I alone in this frustration?
• Can you tell a story of similar problems?
• Have you found a way around these issues in your system / equipment?
• Has this effected your Disk buying habits? (I always elect the DVD/BluRay combo when available)
• Are there Receivers that offer good Compression with DTS sources?
• Is it my imagination that HDMI and PCM conveyance of DTS is better [less Dynamic Range] than Optical?
• Are there instances where enabling Dynamic Range Control in a disk player in combination with Bitstream re-encode seems to make the problem worse, not better?
• Can you comment on Audyssey in this regard?

Thank you in advance for your thoughts and opinions.

Thank you for being the first to respond.

In researching these forums for answers previously, I have seen this comment from you elsewhere. I guess you're right - I do not agree.

If for no other reason than the one that you yourself suggest - today's receivers often have format specific features that are enabled only in specific codecs. To the point - this very issue was considered in the design of Dolby Digital and most receivers implement the Compression features. Apparently not so with DTS.

Like it or not, my equipment seems to result in the widest dynamic range when sending DTS [Audiophile Bitstream] over optical to my receiver. Sent as PCM to the same receiver over the same optical cable and channel yields at least a 6db reduction in range for some material. I do not know the reason why.

Channeling the same PCM over an HDMI is also treated differently by the receiver, and again yields different results.

DTS Bitstream re-encoded as Dolby Digital enables the same Compression features, but does not always seem to result in a noticeable reduction in range when those are selected.



Should I take it then that you are satisfied with the Dynamic Range results your systems provide and you applaud the transition to DTS as the pre-eminent and preferred format?

Thank you. You're helping me quite a bit.

Note: in the following I'll use "DRC" to mean Dynamic Range Compression.

I just spent a few minutes trying various sources on my receiver via HDMI and Optical in both Bitstream [unprocessed] and PCM modes. In each instance I noted the Receiver's detected audio mode

Summary:

Lawrence of Arabia BD DTS MA
T2 Skynet BD DTS MA
Star Trek BD Dolby HD

When the Blu-Ray player is set to output in PCM, my receiver displays emblems for DTS and Neo6 for any 2-channel content. When I set to PCM over Optical, this was triggered. When over HDMI, another setting for Multichannel PCM was triggered, and recognized as 5.1.

In none of those cases were the DRC features present, but as you might imagine, being processed by the receiver as 2 ch effected the Dynamic Range.

Content played with the player in Bitstream mode - yeilded completely different results.
Apparently, DTS-MA content is being sent as ordnary DTS over optical. Being DTS, the DRC features aren't active - but it was still perceptibly different.

Dolby HD Audio on the other hand always enabled the DRC features, whether via HDMI or Optical, as one would expect.

So the reduction in dynamic range I experienced in Optical PCM was due to being in a 2-channel mode I didn't realize. The surround processor applying Neo6 to this apparently gave enough channel differentiation to not be interpreted by me as just stereo.


What I'm realizing is that if I change to PCM optical modes, I may be able to get something I can listen to at low levels and still be better than Analog inputs. It's nowhere near as satisfying as Dolby content, but it may be an alternative if DTS is just too harsh. This is effectively what my Playstation 3 did as a BD player via Optical - All DTS was sent as Pro-Logic. [ Prior to switching to my Re-encode capable unit]


Yes, I agree - apparently Bitstream Re-encoding isn't able to do this as I'd hoped. Sometimes it is effective, sometimes not. To elaborate - there are a few occasions when full dynamic range is ok. During the day, when I'm focused on watching a video it's ok. [I'm alone in the home then] In the evenings it's a completely different matter. This is most of my "quality time" - when someone else is trying to sleep. [11pm to 4am] Sub sonic rumbling of furniture on the floor above and gunfire are not appreciated during these hours. The upstairs HD plasma flat panel has AGC. This evens out all the audio issues, but it's only 50 inches. The home Theater setup [downstairs] is a 100" HD projector with the THX surround processor so not only is it more remote to the sleepers, but it is the preferred display.
I resist this as the explanation. If this were true, why would Dolby sound so spectacular in my setting, and DTS so consistently out of control? Why would reducing the Dynamic Range work? The room is the room, and the THX speakers, the speakers. [Powered Sub-woofer and all] DTS may be truest to life, but that's not suitable to all situations.

I'm spoiled by DRC which is only an option for Dolby content on my equipment and need to get it back. Maybe it's as simple as investing in another brand of receiver. Tearing apart my HT room to sound isolate it from the rest of the house seems an absurd extreme to accomplish something a DSP should easily be capable of.
So I gather, but I've not gotten them to show up as yet. Must be one of the Onkyo quirks. I'll persist.


Thank you for putting up with me - at least I have one explanation of the PCM anomaly.

I think we're finally on the same page.

I take it from the lack of other participants that this is not an issue for many other people. Well, one never knows if they don't ask.


As for Audyssey Dynamic Volume - it's in my HDMI receiver according to the manual. However I didn't complete the microphone based Audyssey setup, so I'm thinking this feature set won't be present till I do. I'm hoping to hear from someone who uses it too.

It's also possible that I've some other setting that's keeping it hidden. My original THX receiver was 5.1, so I have no rear speakers to fill out the 7.1 modes on the newer HDMI unit. [same manufacturer] I tried lieing to it that they're present, to see if Audyssey shows up, and that didn't work either, although the Dolby Surround EX modes did appear.

Are you aware of any Receivers that offer DRC in DTS modes? [all modes actually]

I'm willing to look at others, despite my satisfaction with Onkyo [up till now that is] Will I need to give up THX features to do so?

To be clear - I don't see this as DTS's fault per-se. However, for the industry to adopt a surround format which eliminates any possibility of or consideration that anything other than full theater listening level might be desired, seems very short sighted. Especially when one considers that the standard it superseded Had This Capacity. Foolishly, when BD came out I figured with the huge capacity of the new media, the studios would retain a Dolby Digital track in addition to DTS. Sadly, this only happened in a few titles. It is infuriating, that additional language [non-english] tracks are almost always in Dolby Digital!

I have seriously considered buying all my BDs for another region, just to get a DRC enabled format, and give up the improved quality of DTS at other times. The prospect of constantly needing to disable subtitles and select alternate audio pretty much talked me out of it.

Clearly, I'm doing something wrong to be the only one who cares about this.

Another alternative I've considered is 7.1 headphones.

Hey - there's a new product idea... Wireless active 3D helmet with 7.1 sound!

You added this in an edit while I was responding.

My PS3 is of the earlier generation and doesn't have the hardware to support that feature.

I considered another one, but decided to try a Samsung BD player which had the feature instead. (I explained that above, right? - yes I see I did) Indeed, it does make the DRC settings appear, but they don't always do anything. Some titles they work fine, others they do nothing. (Another anomaly?) Perhaps the PS3 would do better, but I wasn't even certain the new ones had that until recent rumors and the extra $220 seemed a bad gamble.

Maybe someone will post with that experience too.

Just re-checked - the "slim" PS3 is needed to do this. Mine's an older "Fat" one. A firmware update may have been required since the feature was enabled long after the first slim units shipped?

Samsung BD-D6500 3D WiFi - does DTS->DD and DD->DTS re-encode - see manual page 29

... already tried center channel compensations... it just doesn't help that Fog horn in Lawrence when he gets to the Suez Canal.

...LOL - Audyssey - right... Need to get the the microphone from the previous owner. (he won't appreciate me waking him at 2:00am... I'll see him Superbowl Sunday)

Recommend one?

Well, I see what you're thinking JHAz, but I'm not interested in going analog for 8 channels.

As far as dynamic range in the media content, my preference would be that they remain faithful to the original artist's work. (I am an archivist at heart) My disappointment is that the industry is choosing only DTS, a format which effectively deprives me of the way I had of using it in a manner suitable to my needs. I just came back from the Superbowl party, and now have the Audyssey setup mic. I spent some time with his system and can confirm that Audyssey settings and modes are active in Onkyo's menus only after an Auto-setup has been performed with the mic.

Later today, I'll be doing this on my system.

LOL - I see you guys have been having fun without me. Thank you all, for participating.

Rather than quote everyone, I'll just try to answer the points you've all raised.

1) It's not that I "didn't want to", or overlooked the Audyssey setup... I simply didn't have the unit's Microphone to do it until yesterday at 02:00am.

2) "DTS Has way too much Dynamic range..." yep, that's what I said, out of context. What I said was that in choosing DTS, the industry abandoned the Dynamic Range controls inherent to all the implimentations of Dolby Digital. The lack of consideration of this feature leaves me with too much dynamic range for the vast majority of my listening situations. Had Dolby HD been chosen, I would not have any issue - but the industry putting out Blu-Ray media has apparently gone DTS. Hence my frustration.

3) Some have taken my meaning to be that I'm "Dising the DTS format". I suppose I am, because it did not include this consideration from the git-go.

4) You might rightfully criticize me for not taking issue with equipment manufacturers for failing to provide us with compression in their products to deal with the wonderful technology that is DTS. Ok, I plead guilty to that one.

5) I was hoping someone would pick up on the apparent contradiction in my preference for preservation of the "Original Artist's" concept. (Thank you arnyk) By that I mean, for film at least, the director. My hope for most Blu-Rays is that the media preserve to the maximum possible extent (within the capacity of the media) the original theatrical experience.

6) Unfortunately, I can't use the full (range) theatrical audio all the time. The home situation demands something extra - something that used to be there, but no longer is because of the exclusive selection of DTS. It's there if I want French, or Spanish, but not the original language I paid for - english. (in my case)

7) ...Idiots? Sorry, there are no idiots in this thread... yet. Everyone is expressing an opinion, owning their POV and doing so in good faith and with passion. That is what I invited, and that's what I'm getting. I need to take responsibility for my delivery of the message if it doesn't measure up to what I mean.


So why did I start a thread about the issue of "HT Dynamic Range Considerations" and not an "I hate DTS" thread? Because I was hoping to learn how others are handling the issue of Dynamic Range, and to see if there were others out there like myself. What I hear some of you saying is that Audyssey is sufficient for those of you who use it. Still, I'm a little surprised no one has yet responded with some level of agreement. Oh well.

As of this writing, you'll be pleased to know that I've performed several Audyssey setups on the system, and played with the results.

Indeed, there is a noticeable difference - as many of you knew there would be. However, it seems this unit does not in fact have Dynamic Volume, only Dynamic EQ. My friend's new unit has both, so I'll be able to experiment with his to see if the combination is sufficient. Apparently Onkyo thinks the Dynamic Volume feature was worth adding to their product. I wonder why?...

In the meantime, I've arrived at a compromise which seems to get pretty close. The combination of Dynamic EQ and Dolby Digital Bitstream Re-encode (in the BD player) seems to work, provided I adjust receiver levels so that an indicated volume of -10db provides a good sound level in the room and I don't use THX listening modes. I still have a number of subjective evaluations to do, but the "Fog Horn on the Suez" described in a previous post, no longer "wakes the dead".
Edited by 50BMG - 2/4/13 at 11:24pm

Hey Jim... Is that new avatar form the original Star Trek series "Mirror Mirror"?
Nice.


Perhaps this is so. But it may also be an evolution of awareness.

My first THX Surround Receiver was vintage 1997-1998 (Onkyo TX-DS939). Although DTS was introduced ~1993 (with Jurassic Park ?) it wasn't mainstream in homes by the 939, which didn't have any provision for it at all. The new model (989) with DTS was months away (~2000), and DTS wasn't even on my radar. I understand there was an upgrade to the 939 for DTS, but in retrospect that wouldn't have had DV or DEQ and would only have driven me nuts earlier.

The first reference to Audyssey Dynamic Volume is ~2008.

This latest Receiver I've recently acquired was introduced in ~2008. It's by no means top, or bottom of their line as it is a THX unit. It's my first with HDMI, which is the primary reason I spoke up for it when we upgraded my friend. DTS kind of came along for the ride.

I guess now that I'm aware of how important Audyssey Dynamic Volume and it's THX counterpart is to me, it will be indispensable in my next unit. Very good to know.

Thanks for weighing in mtbdudex. I don't feel quite so alone now.

Having evaluated Audyssey Dynamic Volume on the Onkyo TX-NR616 earlier today, I conclude it's possibly even more effective at the most aggressive setting than the Dolby Digital "Late Night" modes. The caveat is that for DV to be selectable, DEQ must also be enabled. This is a little counterproductive given that DEQ boosts low frequency content, but it's manageable with a reduction in the subwoofer or by a higher DV setting.

It's worth noting: On the newest Onkyo receivers, the setting of Audyssey functions is saved and remembered from one powerup session to the next. Not always so with the Dolby Late Night mode setting. Some models have the optional ability make the setting persist, others forget and powerup with it "off".


Now that I'm aware of Audyssey, I've been able to re-search forum threads here at AVS. I find that this issue has been raised and discussed previously, although not correlated as directly to DTS in most cases. (but a few did)

In those and other selected readings, I am very impressed with the breadth of knowledge displayed there, by those of you who took time to post here. I was particularly interested in a thread which got onto surround speaker reflection effects, and their identification / management. ([jim19611961 - you posted quite a bit in that one)

Again I thank you all.


So far, I see that other manufacturers have implemented Audyssey or have invented their own technologies to deal with this issue.

The one's most discussed seem to be Denon, Yamaha and Marantz.

Please, if you have one of those, or another I am not aware of - consider posting a few words about how you feel about them? Negative or positive, standalone or compared... whatever. Despite being primarily an Onkyo devote, I am not so thoroughly ensconced that I wouldn't consider changing. I really would prefer to stay with a THX certified unit however. (If you've been reading, you already realize that)

I actually plan to seek out some Denon receivers at local showrooms, to play with and give them a listen. There aren't as many equipped showrooms around as there used to be and I'd really value your experiences.

Here's a technical question...

What is the effect on Dynamic Range of local noise?

The HT setup I've been using is in the corner of a fairly large, below grade space. Walls and floor are concrete. Previously, the area was carpeted and had insulated studded walls with various surface treatments, which have now all been removed.

This allows local sounds of A/C circulating fan, PC power supply fans, and HE water heater noises to infiltrate the space at varying levels.

All that has the effect of raising the noise floor in the area of the HT. It's not much, but at lower listening levels, it couldn't help but obscure the lowest parts of the content.

How would you view these interferers in terms of impact on Dynamic Range?


Just curious.

Well, I need to get used to some new scales then...

I think my THX systems calibrate 0db = 85dbSPL, doesn't it? If I recall, this happens to be the maximum allowable long term (recurrent) level before hearing damage is a concern.

Coming from a telecom / broadcast electronics background, I'm not used to thinking about things that could be much over 70db in range, without needing hearing protection. An auditory noise floor lower than -65db is very quiet indeed. (one's breathing sound, heart sounds and swallowing are actually about that) Normal conversation on that reference would be around -15db, with hearing damage expected at around 35db and pain at 45db.

The notion that a sound system could have a useful 90db range is new to me, to say the least, as it already exceeds the limit of safety even if it begins at the threshold of hearing.

I guess that subjectively, a director might try to provide a film with sounds meant to compete with one's sense of self. (Heartbeat, breathing etc...) This would require the sound environment to be quiet enough that those are above the audience's abient noise. That's a lot to expect, given today's multi-venue theaters.

Is there typically any way to access the absolute levels obtained during the Audyssey calibration?

That might be fun. Probably too much to expect also.


Am I looking at this about right, or am I missing something... "OUCH" is right!
Edited by 50BMG - 2/9/13 at 5:16pm