If you have a sub that can hit reference level in a given room does adding “more” sub change or enhance the sound. The director intended a certain SPL to be hit in a given scene. Assume the goal (reference level) is to hit that level. If the system is set up properly with the channels even, sub included. Then will adding more sub improve or enhance the sound.

I understand this theoretical question is flawed because of the effects of the room on FR but given a decent FR what is the point of diminishing returns and how would you measure it? Lets limit it to one sub or at least co-located subs.

If you have a sub that can hit reference level in a given room does adding “more” sub change or enhance the sound. The director intended a certain SPL to be hit in a given scene. Assume the goal (reference level) is to hit that level. If the system is set up properly with the channels even, sub included. Then will adding more sub improve or enhance the sound.



Yes. Typically when a sub is able to "hit" reference levels, (usually considered to be 115db), it is often doing it at it's limits. A sub never sounds best at it's limits. It sounds best when it's still got a bunch of headroom. So even if the sub can hit reference, if there was a second sub in the room sharing the load, or an even more capable sub, the sound will be much cleaner, accurate, and more powerful.

It's all about THD and IM distortion. If both of those are low when hitting reference, then adding more subs won't really do much.

Getting there with 1 sub is isn't easy. Off-hand these are the *single* commercial subs that can probably do it-

Servodrive contrabass
Danley DTS-20
ED A7-900
Epik Conquest?

From there you start needing duals for reference level at reasonable distortion levels.

It's all about THD and IM distortion. If both of those are low when hitting reference, then adding more subs won't really do much.

Getting there with 1 sub is isn't easy. Off-hand these are the *single* commercial subs that can probably do it-

Servodrive contrabass
Danley DTS-20
ED A7-900
Epik Conquest?

From there you start needing duals for reference level at reasonable distortion levels.

What is IM distortion?

http://en.wikipedia.org/wiki/Intermodulation

you can NEVER have too many subs my friend.... :-)

Mr. Evil, I realize you are kidding. But there is definitely diminishing returns. I am wondering how to identify if you have reached that point.

I don't care what the "director" had in mind as far as sound level. Reference level is way too loud for me 98% of the time. And Reference Level may be 105 db, not 115 db.

But if you want to visit Reference Level, don't stop with the subwoofers. You need main and surround speakers that can reach reference level as well. This may require some serious main speakers.

The problem with Reference Level is that dialogue is presented much lower than special effects. So, dialogue presented at Reference Level may not be too loud. But, when the special effects come along and jump up 30 db, you are going to jump out of your seat. This is more uncomfortable than fun.

Please be aware that prolonged listening at 85 db and louder will lead to hearing damage. This applies to mid range frequencies much more so than low frequencies. Still, you don't want to expose your ears to 105 db bass for long periods either.

I understand reference level is way too loud. It says assume the goal is reference level. You need a point everyone can understand.

The question is how do you know when you have enough? When you have reached the point of diminishing returns.

There are many people on this forum who have gone through several upgrades. I'll wager some "upgrades" were really not. The second sub or the better sub my have had been a marginal improvement, the juice may not have been worth the squeeze if you know what I mean.

How do you make an informed decision?

The answer is certainly not post a question on this forum. No matter what you some will suggest, get 2 of what you have or something better. ;)

I understand reference level is way too loud. It says assume the goal is reference level. You need a point everyone can understand.

The question is how do you know when you have enough? When you have reached the point of diminishing returns.

There are many people on this forum who have gone through several upgrades. I'll wager some "upgrades" were really not. The second sub or the better sub my have had been a marginal improvement, the juice may not have been worth the squeeze if you know what I mean.

How do you make an informed decision?


The answer is certainly not post a question on this forum. No matter what you some will suggest, get 2 of what you have or something better. ;)

There is a way you can tell if you have enough or not. You listen to some challenging movie scenes and gradually increase the volume up to the level where it is as loud as you would ever really want to listen. If there is a point at which the character and quality of the sound begins to change for the worse, that is the approximate useful upper limit of your system. Is that level enough for you?

There is a way you can tell if you have enough or not. You listen to some challenging movie scenes and gradually increase the volume up to the level where it is as loud as you would ever really want to listen. If there is a point at which the character and quality of the sound begins to change for the worse, that is the approximate useful upper limit of your system. Is that level enough for you?

I would say as far a overall volume and sound quality yes.
Can there be more bass or is there more bass that I am not getting due to the system limits? I don't know. How could I. Should that last explosion have moved my chair across the room?

I would say as far a overall volume and sound quality yes.
Can there be more bass or is there more bass that I am not getting due to the system limits? I don't know. How could I. Should that last explosion have moved my chair across the room?

For an explosion to have the kind of impact you're talking about, you need more volume than anyone should be messing with. Playback of recorded explosions should be convincing, perhaps even frightening, but don't ever believe that 115db is anything like the real thing. If done well, a movie explosion can certainly be felt throughout your body.

One way to learn about the limtations of your own system is to listen to a system that you know to be better than yours. If you come away thinking your own system sounds like crap, that tells you something right there.

Another way to learn more about your system is to learn to measure and graph the bass response. The free REW software available for download on Home Theater Shack + an SPL meter + a laptop can give you the tools to do so. You may be shocked to see certain irregularities in your bass response that may be correctable by repositioning, acoustic treatments, or eq.

Refererence level is 105dB per speaker channel, and 115db for the LFE channel.

With your amp power and speakers, can you hit 105dB per speaker at the listening position without clipping?

I would say as far a overall volume and sound quality yes.
Can there be more bass or is there more bass that I am not getting due to the system limits? I don't know. How could I. Should that last explosion have moved my chair across the room?

There are various kinds of improvements. For some, EQ and/or room treatments would be an improvement.

For others the quality of the sound may leave room for improvement. Recently there have been an increasing number of people who are finding that the sound quality of sealed subs is more to their liking than the sound of ported subs. That's why there is more mention of the Rythmik and HSU sealed subs, (not to mention the J L Audio F113, F112 and G213), Ed A7S-450, etc.

Still others are more about output and extension than they are about the ultimate in sound quality. These tend to be the hobbiests who are always wondering what 130 db would sound like.

There is at least one more group. Those who believe in the "new definition" of a subwoofer. These are typified by someone like Tom Nousaine, who has tested hundreds of subwoofers. When he got a well done presentation of the Thigpen Rotary sub that is virtually flat to 4 Hz at 110 db he had a new point of reference. Too bad the TRW-17 costs $13,000 plus installation.

Having said all that there are some who after reading this section of the Forum, decide that they must be missing something even though they were satisfied before they started reading about subs that can do 115 db or more, or have better sound quality.

Then there are a few people who don't mind spending a considerable amount of money to try new subs when the spirit moves them.

Compared to someone who has one or two Thigpen Rotaries, you are certainly missing the octave from 1Hz-15 Hz at 110db.

Based on another of your posts, it's not likely that you can achieve Reference Level, 115 db, from 20-80Hz. 4 of what you have would probably get you Reference Level. Is it worth another $3,000?

Only you can decide if its worth another $3,000 to achieve a good bit more impact.

I am not looking for reference level really. I listen fairly loud by myself. -10 MV, -15 with the wife and kids. My use of the word reference was probably a poor choice. The question might be better stated, is the bass as good within reason as deep bass effects can sound? You can increase the sub level relative to the rest of the speakers to a point. Placement is a compromise, the best mid bass impact may take away from the low bass.

My room is treated very well for high frequencies, It has minor bass treatment but there really is not room for more. I think there is some room for improvement in placement and “tuning”. I don't want to get into serious room measurements and or EQ's. That will prolong and deepen the psychosis.

Truth is I should finish tweaking and sit back and enjoy. The problem is that if you buy a second identical sub within 30 days you get a discount….. you see the dilemma.

. That will prolong and deepen the psychosis.



You make it sound like psychosis is a bad thing!:p:D:p

Bad, maybe. Time consuming and expensive definitely.

I am not looking for reference level really. I listen fairly loud by myself. -10 MV, -15 with the wife and kids. My use of the word reference was probably a poor choice. The question might be better stated, is the bass as good within reason as deep bass effects can sound? You can increase the sub level relative to the rest of the speakers to a point. Placement is a compromise, the best mid bass impact may take away from the low bass.

My room is treated very well for high frequencies, It has minor bass treatment but there really is not room for more. I think there is some room for improvement in placement and “tuning”. I don't want to get into serious room measurements and or EQ's. That will prolong and deepen the psychosis.

Truth is I should finish tweaking and sit back and enjoy. The problem is that if you buy a second identical sub within 30 days you get a discount….. you see the dilemma.

Dude

I don't know your financial position. I would ask you this. Do you have a display that is as good as your subwoofer in size and picture quality?

I see a lot of pictures of people who have $4,000 worth of subs but are watching a 42 inch display.

I would tell them that their display is not in balance with their bass. If you don't have at least a 50 inch 1080P display, don't add any more subs now.

What display do you have?

There are various kinds of improvements. For some, EQ and/or room treatments would be an improvement.
the Thigpen Rotary sub that is virtually flat to 4 Hz at 110 db he had a new point of reference. Too bad the TRW-17 costs $13,000 plus installation.

Only you can decide if its worth another $3,000 to achieve a good bit more impact.

The cost of installation could be massive as the unit requires a room roughly equal in volume to the HT to properly load. If you have the room, great but if you don't the construction costs could be staggering.

As an aside, the latest THX clip that has the plants with the subwoofer mushrooms is simply amazing. My first experience was with my stereo SH50/TH50's in my 18'x20'x10' HT and I actually got blurred vision on the mushrooms,(For those of you from the '60's, I'm not talking about those kind of mushrooms)! Of course, we played the track repeatedly enjoying our optical massage!

Mike Hedden
Danley Sound Labs, Inc.

Yeah, I now use that THX intro for a demo. Awesome bass in spl and quality

I have a 100" Stewart Firehawk Screen in a dedicated HT room with a new 1080P projector. A second sub would be the finishing touch on an amazing experience. I am blessed with a bit of financial freedom, it is not money.

I recently got the recliners for the theater which came in a month late. They were the final thing. Until then I was on lawn chairs. When I did the Audyssey readings with lawn chairs I pushed them out of the way and set the tripod. When I did the readings with the recliners I had to set the tripod half on the recliner. In doing so I set the microphone too close to the back wall. It was picking up the corner effect and Audyssey was dumbing down the bass as it should. My bad. I re-did the readings correctly. I turned Dynamic EQ on the receiver on which adjusts EQ up for less then reference volume and listened to the sound canon scene in The Hulk BD at -10 MV. It was over the top. My problem was a loose nut 12" behind the remote.

I have a new HSU ULS-15. I have been dialing in location and settings for a week. Because of all the changes I have made I was getting mixed results and doubts. I had done a lot of measurements with my RS SPL meter and thought I had found the right spot for the sub. It is flat to 16 Hz (that's not in the graph I also don't have a 200 HZ tone hence the 0) and maybe lower but I don't have a lower tone I figured I have the right room this is perfect. Then after I re did the Audyssey I was bumming. Hence the post.

I can now say the ULS is over the top. The Hulk sound canon scene was near uncomfortable bass wise, about perfect. The bass is tight and loud.
With music it is perfect, it blends in and doesn't stand out but it is strong.

Again, it was a loose nut 12" behind the remote, that reads the forums a little too much. At this point I give the big thumbs up to the HSU ULS-15.. I definitely don't need 2.


http://bill-stan.smugmug.com/photos/421315521_Lpj57-L.jpg
Thanks

Bill

I think the idea is to get a subwoofer that is capable for your room, and get that sounding good. Then adding more subs it should sound should sound the same at your soundstage, and in more locations. The nice thing is not worrying if one movies bass is more than the next because the quality sounds the same. There is the potential for movies with less than stellar bass to shine through, but that usually is not an issue unless you watch lots of movies, and most none of heard of.

As an aside, the latest THX clip that has the plants with the subwoofer mushrooms is simply amazing.

Mike Hedden
Danley Sound Labs, Inc.

Where can I get this?

THX trailers (http://thx.com/cinema/trailers.html) and the new Indiana Jones Blu-rayWhere can I get this?

beginning of the indiana jones 4 bluray and clone wars as well.

What it comes down to with the ability to hit Reference on the sub at the seats is having a system with enough headroom to not distort or compress on high level transient peaks and medium high level sustained notes.

Subs like the Danley DTS-20, TH-SPUD and TH-50, the JTR Captivator, Seaton Terraform XL all have a very very effortless sound to them. People keep making the comment that they sound very very clean and musical and that is directly related to the fact most folks won't be pushing them hard. Most consumer grade subs are pushed to the limits, going into compression and rising distortion on more and more of the big film releases. When people say the LFE sounds "uncomfortable" at high levels, it is that distortion which is giving you the problem. A true reference sub system that CAN hit reference at the seats won't give you that uncomfortable feeling...it simply impacts your body in a way many people find addicting (MUST...HAVE...MORE........BASS)

In addition, people want deep extension. You see subs spec'd out to have deep frequency extension. But it is not just about how deep a sub goes, it is also about whether the sub is capable of substantial amounts of output at those frequencies. This is where the old adage if there ain't no SUBstitute for cubic inches comes into play. Take an sub like the Epik Conquest...one of the better consumer grade subs out there. It will do 104 db at 16 hz measured in room. Pretty darned good to say the least...most consumer subs are well below 100 db at that frequency. The JTR Captivator will do 114 db at 16 hz... a good solid 10 db more headroom. This means when a seriously deep frequency comes along...which happens a lot in big films these days, the subs like the Captivator, SH-50, etc. will reproduce it without creating distortion. The drawback...those subs are physically large...though all of them will easily fit behind a screen wall and subs like the Danley TH-SPUD can work in most any room. Once you've had that experience of a sub with truly deep, capable output in your room, you won't go back.

What it comes down to with the ability to hit Reference on the sub at the seats is having a system with enough headroom to not distort or compress on high level transient peaks and medium high level sustained notes.

Subs like the Danley DTS-20, TH-SPUD and TH-50, the JTR Captivator, Seaton Terraform XL all have a very very effortless sound to them. People keep making the comment that they sound very very clean and musical and that is directly related to the fact most folks won't be pushing them hard. Most consumer grade subs are pushed to the limits, going into compression and rising distortion on more and more of the big film releases. When people say the LFE sounds "uncomfortable" at high levels, it is that distortion which is giving you the problem. A true reference sub system that CAN hit reference at the seats won't give you that uncomfortable feeling...it simply impacts your body in a way many

In addition, people want deep extension. You see subs spec'd out to have deep frequency extension. But it is not just about how deep a sub goes, it is also about whether the sub is capable of substantial amounts of output at those frequencies. This is where the old adage if there ain't no SUBstitute for cubic inches comes into play. Take an sub like the Epik Conquest...one of the better consumer grade subs out there. It will do 104 db at 16 hz measured in room. Pretty darned good to say the least...most consumer subs are well below 100 db at that frequency. The JTR Captivator will do 114 db at 16 hz... a good solid 10 db more headroom. This means when a seriously deep frequency comes along...which happens a lot in big films these days, the subs like the Captivator, SH-50, etc. will reproduce it without creating distortion. The drawback...those subs are physically large...though all of them will easily fit behind a screen wall and subs like the Danley TH-SPUD can work in most any room. Once you've had that experience of a sub with truly deep, capable output in your room, you won't go back.

"Once you've had that experience of a sub with truly deep, capable output in your room, you won't go back."

Yes, if you let yourself get cautht up sufficiently to bring a Danley or the like INTO YOUR ROOM, you won't go back. Most of us are not going in that direction though.

However, lots of Epic Conquests have been sold as well as PB-13 Ultras, and J L Audio F113's. I would guess that anyone with one of the three subs I just mentioned is in the top 5% in terms of subwoofer capability.

The OP is not exactly interested in Reference Level, he is just teetering on the edge of adding a second sub of the same kind he just bought because he can save some money if he buys a second within 30 days. He has the money, but wants to know how big a difference a second sub will make if he spends another >$1,000 for the second sub.

I've seen enough of his posts to say that he ought to go ahead and spend the money and he will be in very good shape except compared to those in the top 5% who are willing to go with pro style subs like the ones you mentioned.

The problem with Danley subs (and pro audio stuff in general) is the whole PA system look. It may be capable of humongous output, but it sho ain't good lookin'...:) There needs to be a balance of good looks and loudness. I don't want my baby to have a bag over her head.

The problem with Danley subs (and pro audio stuff in general) is the whole PA system look. It may be capable of humongous output, but it sho ain't good lookin'...:) There needs to be a balance of good looks and loudness. I don't want my baby to have a bag over her head.

Beauty is in the eye of the beholder :p

A lot of folks use these behind screen walls. I have one client who built a DTS-20 into a cabinet in the room, another who built one into the wall. There have been a few guys using the DTS-20 under the screen and putting the center channel on top with a fabric covering over the sub. Looks really good. Another thread with the new Danley TH-SPUD painted and against the front wall to look like an acoustic panel...plus at 11" deep, that sub is ideal flipped on its' back for use as a riser platform (or built into one). The Captivator is best behind a screen wall or finished in automotive lacquer and proudly displayed as the beast it is (only $400 for the lacquer finish option).

Also, any of them are available in the fancy schmancy wood finishes...heck I have the only Zebrawood SH-100B's on the planet.

Point is, if you really want one, there are solutions to make them domestically acceptable and even completely hidden. There really are no excuses for not owning one and no consumer subs will do what these beasts of bass will do.

Beauty is in the eye of the beholder :p

A lot of folks use these behind screen walls. I have one client who built a DTS-20 into a cabinet in the room, another who built one into the wall. There have been a few guys using the DTS-20 under the screen and putting the center channel on top with a fabric covering over the sub. Looks really good. Another thread with the new Danley TH-SPUD painted and against the front wall to look like an acoustic panel...plus at 11" deep, that sub is ideal flipped on its' back for use as a riser platform (or built into one). The Captivator is best behind a screen wall or finished in automotive lacquer and proudly displayed as the beast it is (only $400 for the lacquer finish option).

Also, any of them are available in the fancy schmancy wood finishes...heck I have the only Zebrawood SH-100B's on the planet.

Point is, if you really want one, there are solutions to make them domestically acceptable and even completely hidden. There really are no excuses for not owning one and no consumer subs will do what these beasts of bass will do.

hey Soundood, the Captivator has a 15" active driver on the front of the box and a 18" PR on the rear of the box? and it's a passive sub correct ?

hey Soundood, the Captivator has a 15" active driver on the front of the box and a 18" PR on the rear of the box? and it's a passive sub correct ?

No, No and Yes. The Captivator has an active 15", but it is internal. The 18" passive is on the front, and it is a passive sub, so you do need an amp.
Having a driver on the back...that thing would take up WAY too much depth.

The active driver is slot loaded. Mark Seaton, who designed it, explained the design in another thread but put it this way...it bloody well WORKS! :D

Great topic. I love listening at 0db MV (Master Volume). That is calibrated at 75db not 85db, so I may be a tad low at 0db MV.

I use four 15" sealed subs with about 6,000watts of power. Not to mention a black box to extend their response down into single digits. Once that was built I discovered my mains (LCR) could not keep up. So, I built new ones and new surrounds to match them.

As many have mentioned it's about headroom. Defined as ability above and beyond demand. Your room is unique and what works for me in my room may not perform in your room.

As always I suggest the DIY forum and see what the guys are building to reach the goals you are looking for. It's cheaper and the bigger you build the greater the return with out the diminished funds.

Kg

It would be nice to hook up with a member in your area to get a listen to reference level in person. It's kinda difficult to put down in words.

"It would be nice to hook up with a member in your area to get a listen to reference level in person. It's kinda difficult to put down in words"
That's the problem. There is only one other person in my area that I am friends with who has a system. My audio is way above what he has. I am pretty happy with what I get from a single SubMersive in a 1000cf room. With my amps and subs I have about 2050 watts. Give or take depending on if you believe the test reports for my amps. I mean, I have heard systems that had fantastic dymanics. The Cinepro system is my frame of reference for that.

I was watching VanHelsing last week, and the scene where they are transporting Frankinstein through the forrest is so damn intense. The musical score goes right through you......at reference level. I love it !!!

It really is the benchmark. Problem is your system has to be able to handle well above that to be able to sustain the peaks. It's no red herring, and no easy task. My system has gone through many upgrades to reach this point and it has been an education all the way. I've learned so much from you guys!!

Kg

PS Now that the audio is where I want it, the pj could use some upgrading.It's a 720p CIH.Would be nice to see BR in all its glory.....

Keep in mind Dolby Reference Level was intended for movie threaters, not necessarily average joe living rooms. For 99% of us it would simply be way too loud. Sometimes I actually find theaters to be too loud.

Smaller rooms won't need to be calibrated to 85 dB.

Keep in mind Dolby Reference Level was intended for movie threaters, not necessarily average joe living rooms. For 99% of us it would simply be way too loud. Sometimes I actually find theaters to be too loud.

Smaller rooms won't need to be calibrated to 85 dB.

I agree. I use to calibrate to 85db by hand and 0db MV was way too loud. Now that I auto calibrate with Audyssey @ 75db, 0dbMV sound great with 95% of the movies I watch.

It's a great point to get your system to. Then back it off to -10 or -15db and you'll have the headroom you need to enjoy a whole movie without reaching for the volume every ten minutes.

Kg

It's a great point to get your system to. Then back it off to -10 or -15db and you'll have the headroom you need to enjoy a whole movie without reaching for the volume every ten minutes.

Kg


Yep. That's where I'm at. I generally listen at -15 dB from reference and occasionally push it to -10. For example, I was listening to Iran Man (Blu-ray True HD) at -10dB from reference today breifly listening to the sonic boom and then the jericho missle explosion. Both of those hit 108 dB (uncorrected)! It was awesome.:D The system handled it well and the Ultras sounded phenominal. It put a smile on my face.

Yep. That's where I'm at. I generally listen at -15 dB from reference and occasionally push it to -10. For example, I was listening to Iran Man (Blu-ray True HD) at -10dB from reference today breifly listening to the sonic boom and then the jericho missle explosion. Both of those hit 108 dB (uncorrected)! It was awesome.:D The system handled it well and the Ultras sounded phenominal. It put a smile on my face.

I've yet to experience BR-True HD. Maybe someday soon.

The recommended level for *mixing* in a smaller studio (similar to most home theaters) is 79-82db. So playback at that level will give you a very close approximation of what the mixer heard.

What it comes down to with the ability to hit Reference on the sub at the seats is having a system with enough headroom to not distort or compress on high level transient peaks and medium high level sustained notes.

Subs like the Danley DTS-20, TH-SPUD and TH-50, the JTR Captivator, Seaton Terraform XL all have a very very effortless sound to them. People keep making the comment that they sound very very clean and musical and that is directly related to the fact most folks won't be pushing them hard. Most consumer grade subs are pushed to the limits, going into compression and rising distortion on more and more of the big film releases. When people say the LFE sounds "uncomfortable" at high levels, it is that distortion which is giving you the problem. A true reference sub system that CAN hit reference at the seats won't give you that uncomfortable feeling...it simply impacts your body in a way many people find addicting (MUST...HAVE...MORE........BASS)

In addition, people want deep extension. You see subs spec'd out to have deep frequency extension. But it is not just about how deep a sub goes, it is also about whether the sub is capable of substantial amounts of output at those frequencies. This is where the old adage if there ain't no SUBstitute for cubic inches comes into play. Take an sub like the Epik Conquest...one of the better consumer grade subs out there. It will do 104 db at 16 hz measured in room. Pretty darned good to say the least...most consumer subs are well below 100 db at that frequency. The JTR Captivator will do 114 db at 16 hz... a good solid 10 db more headroom. This means when a seriously deep frequency comes along...which happens a lot in big films these days, the subs like the Captivator, SH-50, etc. will reproduce it without creating distortion. The drawback...those subs are physically large...though all of them will easily fit behind a screen wall and subs like the Danley TH-SPUD can work in most any room. Once you've had that experience of a sub with truly deep, capable output in your room, you won't go back.

While I don't disagree that the subs you mention are in a different class I believe you are making a leap assuming what I meant by uncomfortable. When the pod emerges in WOTW and people begin to be vaporized there are many reasons to be uncomfortable. Hopefully you are not analyzing the subwoofer and you have become engrossed in the movie. Then the shear intensity of the output of the sub is disorienting. When in life do you hear sound that loud and intense. The purest sound in the world too loud is just too loud. I also become uncomfortable as I image the look on my wife's face as her cup of coffee starts moving across the kitchen table. ;)

While I don't disagree that the subs you mention are in a different class I believe you are making a leap assuming what I meant by uncomfortable. When the pod emerges in WOTW and people begin to be vaporized there are many reasons to be uncomfortable. Hopefully you are not analyzing the subwoofer and you have become engrossed in the movie. Then the shear intensity of the output of the sub is disorienting. When in life do you hear sound that loud and intense. The purest sound in the world too loud is just too loud. I also become uncomfortable as I image the look on my wife's face as her cup of coffee starts moving across the kitchen table. ;)

The bass sounds right when it's intensity matches what's happening on the screen. It shouldn't distract you from the screen action. It should make what's going on seem more real. In WOTW, the intense bass is logical. When the pods emerge from the grouind, it sounds like an earthquake. When folks are bing vaporized, it sounds like an enormously powerful ray hitting someone. In some other movies, the sound is just stupid. Pulse, for example.

The bass sounds right when it's intensity matches what's happening on the screen. It shouldn't distract you from the screen action. It should make what's going on seem more real. In WOTW, the intense bass is logical. When the pods emerge from the grouind, it sounds like an earthquake. When folks are bing vaporized, it sounds like an enormously powerful ray hitting someone. In some other movies, the sound is just stupid. Pulse, for example.

I agree

Synergy is key. Capable subwoofers, mains that can keep up. Surrounds that are positioned correctly and matched in timbe and level to envelope. Dark room, big, wide, picture (2.35:1)(with a good lens). For me an AT screen, so voices are centered not below or above. Acoustic treatments to absorb all that output and diffuse all that output. Enough power on hand at the wall outlet to power all the amps needed to drive all the channels.A world class receiver (Denon 3808ci) acting as a processor... and the only thing left is playing the movie.

It's about the pieces coming together. Reference level is a wonderful goal.It's loud and its scary and no one could talk me out of it for the world. I'm a firm believer that once you have heard it done right, you will be hooked.Sit in someones theater that is missing that synergy and you, your wife and everyone else will be put off.

Kg

If you have a sub that can hit reference level in a given room does adding “more” sub change or enhance the sound.


It can. More and/or bigger+better sub-woofers will reduce the distortion level at a given frequency, SPL combination. For example in a sealed sub-woofer distortion might reach 10% at half the mechanical limits at 30Hz but only a quarter the limits at 20Hz. Enough distortion causes doubling where you hear the intended signal an octave higher.

A larger size driver will let you get more bass extension at the same SPL, either directly (because excursion requirements quadruple for each octave lower you play) or indirectly (because the extra displacement lets you push the port tune lower).

It can. More and/or bigger+better sub-woofers will reduce the distortion level at a given frequency, SPL combination. In a sealed sub-woofer distortion might reach 10% at half the mechanical limits at 30Hz but only a quarter the limits at 20Hz. Ported speakers are more complicated.

Enough distortion causes doubling where you hear the intended signal an octave higher.
But if you don't have audible distortion at reference or your normal listening levels, then adding more or bigger subs will not enhance the sound.

Keep in mind Dolby Reference Level was intended for movie threaters, not necessarily average joe living rooms.

That depends on frequency response, distortion, and acoustics. With no accentuated high frequencies, low distortion, and an average 13x19' living room that's not to live it's fine.

With speakers that are distorting it's at least 10dB too loud.

But if you don't have audible distortion at reference or your normal listening levels, then adding more or bigger subs will not enhance the sound.

At sub-woofer frequencies you don't know whether you have audible distortion until you switch to lower distortion sub-woofers or measure the spectrum.

A distorted 20Hz sounds like low-E while a clean 20Hz may just be felt.

At sub-woofer frequencies you don't know whether you have audible distortion until you switch to lower distortion sub-woofers or measure the spectrum.

A distorted 20Hz sounds like low-E while a clean 20Hz may just be felt.
Completely understood.