maxmercy

Lots of variables there.  If I were you, I would sim many options, including the room.  Use WinISD or a similar enclosure program and RoomEQ Wizard's Room Sim.

100dB capability at 20Hz (at the main listening position) means you will be playing movies at around -20dB on your receiver (if calibrated to cinema reference).  For many people, that is enough to satisfy them.  Clean 100dB at 20Hz is not easy on a budget.  With a low budget and limited power (100W), sealed enclosures will limit SPL and extend a bit further down low (using power), vented enclosures will limit extension by essentially 'boosting' SPL above tuning.  If you have woodworking experience, making a tapped horn/folded horn sub will get you a lot more SPL for a limited power/budget scenario.  There are plans out there for these enclosures.  Also multiple subwoofers can help tame room modes.  Nearly every small room low frequency setup benefits from EQ capability, but you have it with the Audyssey built into your receiver.  No need for lots of DSP if your receiver already has it.

I would also recommend buying a used/refurbished sealed/ported sub with an included plate amp which may let you know what will be 'enough' for you and you can then plan accordingly for upgrades.  One or two 10-15" subs should be enough to get you started, and if you are lucky, get a little room gain.  Look at ebay.

JSS

Transformers: Rise of the Beasts - Dolby ATMOS (7.1 DTHD bed graphed)

Level - 3 Stars (108.63dB composite)

Extension - 3 Stars (19Hz)

Dynamics - 5 Stars (27.53dB)

Execution - 3 Stars - OK track.  Not great, not terrible, incorporates several effects from prior films, but does not distinguish itself much.  

Overall - 3.5 Stars

JSS 

Oppenheimer:

Level - 4 Stars (111.3dB composite)

Extension - 5 Stars (8Hz)

Dynamics - 5 Stars (28.9dB)

Execution - 3 Stars by poll.  Very powerful sound, very reminiscent of the great rumbles in other Christopher Nolan films, but at the expense of clipping in every channel except the surrounds in both the 4k and 2k tracks, which appear identical.

Overall - 4.25 Stars

JSS

I see what you mean, I was only talking about ELC and how it relates to my experiences with both sinewaves and real content, in a "high fidelity" system.  I agree, linearity is a huge deal.  Listening/feeling experiences with an old system of mine with large peaks at 30 and 60Hz were significantly different from a later system that had much better control of the room via acoustic treatment, mode cancellation via multiple subs, proper headroom and proper seat placement with some EQ thrown in to tame the largest leftover resonances...that system was very good.

What is strange is that in some movie scenes, the tactile effect of the old, peaky system was far more present.    

Complex subject indeed.

JSS

The article listed on that page:

http://www.filmaker.com/papers/RM-WhtPpr_Subwoofer Camp.pdf

Brings up something that few do, except MonteKay:

http://www.mfk-projects.com/Home_Theatre/theatre_woofer.html

It is a very important point.

Due to the way our ears 'hear', a near infrasonic sound must be played back more cleanly than a midrange sound in order not to have upper harmonics 'color' it due to equal loudness curves.  I did several experiments with my first decently low distortion subwoofer system and it is enlightening seeing total harmonic distortions of just above 1% significantly coloring a pure sinewave tone upon playback at louder levels.  Of course, at loud enough levels, things rattling in the room 'color' the sound far more, until you start fearing for the structure.

Clean reproduction of bass is very difficult.  If you can play a 20Hz tone and with your eyes closed you can point to where the subwoofer is in the room, it is anything but a clean reproduction.  

JSS

I have this film, and this it how it graphs.  From about 1:33 to about 1:39, there is a strong 20Hz effect, you can see it in the average and peak graphs.  At one point it is encoded as hot as 108-109dB If played back at 'Reference Level'.  With a real low distortion playback system, it would lend an ambience to a scene that many would find disconcerting.  Low distortion 20Hz playback is rare to achieve.

JSS

Are the t.amp amplifiers readily available in the US?

JSS

Very nice!

My first sub was definitely not that well finished....

Glad you are enjoying it, but welcome to the rabbit-hole.  You may have just opened the Pandora's box we all have at one point or another...

JSS

Updated the first post links to the corrections.  More BEQ to come, starting with the Lord of the Rings trilogy.

JSS

Interesting question, but I do not know what will happen sim v reality for this.  Will you have shaped and non-shaped cabs built to compare?

JSS

Interesting....they are quite different, windows could account for it, but the level differences are what I see as most prominent.  I wonder if the DTS-HDMA and ATMOS tracks have different dialnorm settings, or something else.

JSS

On 12/24/2019 at 4:22 AM, timcat4843 said:

maxmercy-Please list your top 10 movies on Blu-ray for 2019 with the deepest and most powerful bass.

I have not seen that many films this year, lots of reasons why; I have not had the chance to measure that many either.  So far, the PvA for Ad Astra above looks pretty good, but I have to see it. 

This year I mainly did some BEQ for the films I did buy and see on BluRay, like Avengers:Endgame, Godzilla and Bumblebee, and really looked into the LOTR trilogy as we are nearing the 20th anniversary time on it.  It is one of the film trilogies that did not get a decrease in LF from DVD to BluRay, which was very nice.

JSS

Thanks minnjd!  How is the movie?  The PvA looks pretty good

Godzilla: King of the Monsters - Dolby ATMOS (7.1 channel bed)

Level - 5 Stars (112.7dB composite)

Extension - 3 Stars (19Hz)

Dynamics - 3 Stars (24dB)

Execution - TBD

Overall - TBD

Notes - Loud, but not deep.  Very much like Pacific Rim in the rolloff slope.  BEQ for this film in the BEQ thread.

JSS

I did a BEQ for Godzilla, let me look back and post up stats for it later this week.  I have not measured Overlord.

JSS

1) Yes

2) Some receivers let you know how much correction they are applying as the track first plays.  On my Denon, once the main movie fires up, it will display the bitstream (DolbyTrueHD/ATMOS), and then for a second or two, Dialnorm -4dB.  You can then turn up the film by that amount to have the equivalent presentation.  If you run at the high SPL end of things, turning up the MV by that much can make someone a little nervous if they run at the edge of their system's capabilities.

3) Dialnorm in theory has good uses, especially in TV production.  I have mainly found it annoying, but that is due to my personal experience (and frustration at times) with it.  I just see it for what it is, another bit of metadata DTS and Dolby provided so people could have an option to use it.  Few DTS mixes have dialnorm, but they are out there.

When I examine the audio in a film, I remove dialnorm so I can see clipping more easily when it happens.  Like I said above, I remember playing scenes from Transformers 2 over and over at the same MV level and getting pretty annoyed at the IMAX mix.  I had convinced myself it was a dynamics/compression change, when in fact, it was just a turn of the knob.  4-5dB can make a huge difference in perceived impact at the MLP.  If you have a clean system, play the Star Trek 2009 warp scenes at your cleanest high SPL level, then turn it down by 4-5dB and feel the difference....

I also remove dialnorm when I BEQ a film.  Maybe I need to specify if a mix has dialnorm or not in the BEQ correction so people can set the best MV level.

JSS

Here's how they compare with dialnorm accounted for:

Now that may account for some bad reviews from ppl listening from AVRs.

JSS

I have a possible answer.  I went back and looked at the track data for the ATMOS and DTS tracks.  The ATMOS track has a -26 setting for dialnorm, which means your AVR will reduce the overall volume by 5dB.  I experienced the same thing with Transformers: Revenge of the Fallen.  The regular edition was DTSHD with no dialnorm applied, the IMAX edition was Dolby TrueHD, with dialnorm applied at -27.  When you changed the level to account for dialnorm, the mixes were much more similar.  

If you listened at your normal level, the IMAX version seemed to lack dynamics.  But in truth, it was just being played back 4dB lower.

My experience with it:

https://www.avsforum.com/forum/113-subwoofers-bass-transducers/755493-master-list-dvd-hd-dvd-blu-ray-movies-bass-thread-waterfalls-123.html#post17394243

keep reading and you'll see echoed many similar sentiments about SM:FFH

Great article on dialnorm:

https://hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

JSS

16 minutes ago, AmerCa said:

I don't understand the concept of full LCRS if the bass is going to be redirected to the sub anyways. My rough understanding of the LFE channel was that it contains bass frequencies redirected from the other channels. If you play without a sub, then the speakers play (or attempt to)  its full content, but you wouldn't miss the bass from the LFE channel. That is what would be intuitive to me, anyways, but clearly I'm no expert.

Back to the graph, I'm surprised how close the average linea are in both mixes. They essentially only differ in level. Raising the MV or the sub trim could (or should) close the gaps between the tracks

The LFE channel is a separately encoded channel, that in cinema will ONLY go to the LFE system.  For us at home, BOTH the low freqs from LCRS AND the LFE (played back 10dB hotter) added up go to our subs.  So the LFE channel dominates any PvA graph, and the Avg graph is the average of the whole film, so between these two mixes, they will be close.  In this case, only around 1dB different.  But the Peak graph shows you more in the midbass and upper midbass, sometimes 4-5dB hotter in the DTS track.  That is very noticeable when listening.  That could be in the LFE, or the LFE summed with the LCRS. 

The increased midbass is possibly a reason the DTS track is more highly rated.  Looking at each individual channel between the two will tell us more.  To get down to brass tacks, we can graph specific effects and compare things, but that can get tedious.  If you know of specific effect timestamps that have been panned on the ATMOS track compared to DTS, I can compare them.

JSS

Bumblebee BEQ (ATMOS 7.1 channel bed)

The effects that matter get more weight.  Also got rid of ULF noise in LCRS that was prevalent in the mix.

Correction:

LFE:

1. Gain: -7dB

2. Low Shelf: 10Hz, Slope 1, Gain 6dB

3. Low Shelf: 16Hz, Slope 2, Gain 5dB (3 filters for 15dB total)

4. Low Shelf: 32Hz, Slope 0.5, Gain 2.7dB

LCRS:

1. Gain -7dB

2. Low Shelf 22Hz, Slope 1.2, Gain 5.25dB (3 filters for 15.75dB total)

3. low Shelf 44Hz, Slope 0.5, Gain 0.7dB

4. Highpass Filter, 2Hz, 6dB/oct

JSS

Godzilla: King of the Monsters: ATMOS 7.1 channel bed

Pre-Post:

I initially put too much midbass in the first iteration a page back on this thread, and it was awful.  It works better this way, with more 'heaviness' where needed.

Correction:

LFE Channel:

1. Gain -7dB

2. Low Shelf: 18Hz, Slope 2.5, Gain 6.5dB (3 filters for a total of 19.5dB)

3. Low Shelf: 36Hz, Slope 0.5, Gain 5dB

LCRS Channels:

1. Gain: -7dB

2. Low Shelf: 16Hz, Slope 2.0, Gain 5dB (3 filters for a total of 15dB)

3. Low Shelf: 32Hz, Slope 0.5, Gain 3dB

JSS

Spider-Man: Far From Home DTS vs ATMOS:

Cyan is ATMOS peak, Green is DTS Peak.  Red is DTS Avg, Green is ATMOS Avg.  More midbass overall on the DTS track.  That can make a difference that is definitely felt on a capable system.

If mixers use a cinema dub stage for one mix, and an 'HT' stage for a nearfield mix, it could account for these differences.  The monitoring equipment used can lead to different curves that we measure.  But one PvA for a film can be misleading.

Unfortunately, the LFE channel DOMINATES any Bass PvA, as it is encoded 10dB hotter than the rest of the channels.  This will require looking at the individual channels to see a difference in overall sound quality.  Some of the most sonically impressive films have what appear to be a rolled of PvA with full range LCRS and only a rolled off LFE.  They sound good.  Like the first Iron Man, and the Lord of the Rings FOTR and ROTK.

I saw the film in both DTS and ATMOS w/ BEQ.  I liked both presentations.  But I may BEQ the DTS to see which I like more.  

More on the individual channels later.  It may be telling.

JSS

The tracks graph nearly identically, with a slight edge to the DTS track in overall level with an increase in midbass level (>40Hz), only a slight difference in dynamics, but a definite increase in noise, especially ULF noise in the DTS track, all of which may be below the threshold of hearing.   If I were to BEQ one of the tracks, it would likely be the ATMOS with it's lower noise floor.

I can do a more detailed audio comparo looking at more things + clipping and such when I have time.  I thought the film overall was pretty good, with the lately-typical Marvel great visuals, with sound that is decent, but not outstanding.

I do not have overhead channels, so I cannot comment on the ATMOS experience, only the 7.1 lossless channel beds.

JSS

Avengers:Endgame BEQ (Dolby ATMOS 7.1 Channel Bed)

I finally got a chance to screen it with the BEQ, and it is a substantial improvement.

Correction:

LFE Channel

1. Gain -7dB

2. Low Shelf 17Hz, Slope=1, +6dB

3.  Low Shelf 18Hz, Slope=1, +6dB

4. Low Shelf 19Hz, Slope=1, +6dB

LCRS Channels

1. Gain -7dB

2. Low Shelf 25Hz, Slope=1.25, +5dB (3 filters for +15dB total)

3. Low Shelf 50Hz, Slope=0.5, +1dB

4. PEQ 30Hz, Q=2.87, +6dB

JSS

Spider-Man: Far From Home (Dolby ATMOS 7.1 channel bed)

Level: 4 Stars (111.9dB composite)

Extension: 2 Stars (21Hz)

Dynamics: 5 Stars (29.93dB)

Execution: TBD (3-4 IMO)

Overall: TBD

Notes: 4k disc definitely provided the better track, with 24 bit depth (16 bit for DTS on BD), and slightly higher dynamics.  More low level noise noted on the DTS track.  Some flat tops, but not as bad as other Marvel films.

This track appears to be VERY amenable to BEQ, with a single correction for all channels.  Will post up BEQ later.

JSS