[thebland]

DAY AFTER TOMORROW: D-Theater version.


Sound: 10/10....I have never experienced a more pressurized, powerful, afraid my room was going to explode soundtrack..........Ever! This is of course the DTS, full bit rate track. Amazing surround fill as well. Excellent dialog integration This one has it all in spades. This is my new reference soundtrack as it has multiple scenes where sub 20 hz effects are recorded. Rare and completely astounding!!! I will have to get my meter out but I can tell you there were peaks well over 120 db. Probably 125 db or so.


The wave that builds and then descends and crashes on New York city was the most potent of scenes I have ever experienced...I really feared for my subs and room! It was similar in power to the USS Arizona explosion in Pearl Harbor DTS except that Day after Tomorrow's bass was sustained for many, many seconds and had more subsonic power and detail. I can't even describe it...my shirt seemed to be lifting off my body as this scene progressed!!!


The scenes with the wolves also produced violent, low bass as well.


Yes, I played it at full reference level. It did seem that the recorded level was a bit low. I could have up upped it a few db over reference without a problem but typically turn the processor to the -0 db level and let things go.


Story: 2/10. Typical, predictable and boring.


This is the soundtrack that will expose any weakness in your subwoofers. Truly amazing...I cannot say enough!


I have read that the DTS DVD is very excellent as well and should provide bass heads with some new material to help damage their own systems!


__________________

 

[DMF]

"D-Theater version"?

 

[.jss designs]

Quote:

Originally posted by DMF "D-Theater version"?

http://www.dvhsmovieguide.com/index3.html

 

[RaceTripper]

I agree the soundtrack is pretty amazing, even on the DVD.


I happened to be doing a home audition of a Dynaudio Sub300 subwoofer when I played it. By the time I put this movie in I had the sub very nicely setup. Very impressive sountrack. The movie itself is just OK, but the DVD is worth it for a mindless popcorn evening.


Dean

 

[John Kotches]

Jeff (Thebland) says:

Quote:

I will have to get my meter out but I can tell you there were peaks well over 120 db. Probably 125 db or so.

How high above reference do you have your subwoofers calibrated?


It's your choice, but for me I want to hear all of the soundtrack and as loud as the subwoofers are, you've just obliterated everything else. Might as well go with the Bose cubes at this point for your main speakers, you wouldn't be able to hear a difference


Seriously, recalibrate your subwoofers down to flat in comparison to your mains and hear how much detail you're missing.


Cheers,

 

[Kipp Jones]

Jeff,

care to rent out the tape???

 

[mysphyt]

Quote:

Originally posted by John Kotches How high above reference do you have your subwoofers calibrated? It's your choice, but for me I want to hear all of the soundtrack and as loud as the subwoofers are, you've just obliterated everything else. Might as well go with the Bose cubes at this point for your main speakers, you wouldn't be able to hear a difference Seriously, recalibrate your subwoofers down to flat in comparison to your mains and hear how much detail you're missing.

I set up Jeff's subs and they are calibrated correctly for a flat response, with the possible exception of the 3-4dB kick below 30Hz down to about 16 Hz for that tactile, moves your clothes and hair effect.


Jeff is using pro-grade, unity horn loaded mains that can keep up with the subs to produce THX reference levels at the seats.


With that said, I expect the peak levels were closer to the 120dB (115dB THX reference plus low bass kick) rather than the 126dB mark at reference (although the volume control doesn't actually stop at reference and Jeff has been known to go past it )

 

[John Kotches]

Chris,


I know what speakers Jeff is running, I knew Mark Seaton when he was a college student and part time Hi Fi salesman


Assuming we're talking strictly reference level plus the tweak you are now running 15dB above the mains and you will walk on details that are meant to be heard as part of the overall soundtrack. While I'm sure it's fun, personally I'd grow tired of it after about a week or two.


Still, to each their own.


Cheers,

 

[hometheaterguy]

Why imply listener fatigue when there is near zero clipping and distortion in Jeff's system? With the Runts playing at that output this would not suggest bass heavy as the system is balanced. DAY AFTER TOMORROW: D-Theater version has been our reference disc as well. Non-stop SPL, aspirin not included (I mean that in a good way).

 

[Jesse S]

I measured 122db+ (more like 125db due to RS meter inaccuracy down low) on Andrew's dual contra's. Sounded fine


Is the DVD of DAT not the same audio as the D-theater?

 

[Chronosphere]

What about the "not D" version?

 

[John Robert]

Quote:

Assuming we're talking strictly reference level plus the tweak you are now running 15dB above the mains and you will walk on details that are meant to be heard as part of the overall soundtrack. While I'm sure it's fun, personally I'd grow tired of it after about a week or two.

More like an hour or two for me...


I understand it is clean, "clipless" and distortion free, but why such a huge disparity (15dB) in channel levels?


John

 

[thebland]

John and John,


I understand all the thougts here and I can tell you I am very aware of the sound when all is flat versus the slight augmentation at the vey low end.


Chris and I have gone through great pains to get the audio as perfect ans close to a reference as possible. However, this are a was one area that I had to go with my gut. When I had things flat to 12 or 14 hz, there seemed to be a lack of impact...bordering on a thin sound .


Upping the area fleshed things out and added the impact and realism I longed for.


Things are very tight and I can't see I am losing too much information.


Mind you the subsonic areas of a soundtrack are typically transient and not typically sustained for more than a few seconds at most. My feelings and those I have had over to listen are in agreeance. The bass is unobtrusive.


I can't really explain...you'd all havve to come over and hear for yourself.


I have been to many theaters and haave yet to ever hear what Chris has provided for me. It is clean and authoratative and doesn't get in the way of things.


Remeber, THX specs that the LFE should have a 10 db pop to it. I found 15 db and a augmentation at the lower end to be better. They may have thought this as well but found few subs could deliver so backed things down to 10 db.

 

[Mark Seaton]

I guess this is my que to weigh in...


First, as big a proponent as I am of careful measurement, it is important to correlate what we measure to what we hear. One problem lies in how we measure vs. how we percieve. We basically need to know what is worth worrying about and what may be varying shades of gray.


I would first point out that the response of Jeff's system is not like someone just setting the response of the subwoofer 2-6dB higher than the mains with test tones. What I consider quite critical is the transition region between the subwoofer and the mains, where even if there is an elevation to the response, we want this to be smooth and well integrated. With real rooms there are maybe three major factors to consider in the "shape" of the low frequency response.


The first consideration is based on low frequency reverberation time. I know that during testing for the Synthesis systems Harman found very "dry" rooms to require as much as a 10dB elevation of the bass range to subjectively sound the same as a more reverberant room. Size, construction and how much "soft stuff" is inside dictates this low frequency character of the room. Jeff's room is rather sizable, with a good deal of damping and 12 soft chairs.


The next consideration should be the capability of the main speakers and the subwoofer itself. I have to say it was a remarkable comparison when I demo'd a bDeap in a small dedicated home theater where they had some small, powered Meridians with dual 6.5" woofers which I was able to get a reasonable match with. During this demo I was wondering why it sounded like the bass seemed to be so overpowering of the mains. We then swapped out for three Radicals and I re-calibrated. The point of integration and relative levels were rather similar, yet when we fired up the system, things sounded quite different. All of the sudden the bass was just an extension of the mains, and while still loud and powerful, the integration was maintained at all levels. Had I had to integrate the bDeap with the Meridians I would have had to spend more time working on the integration and probably used a bit of contouring to get something more subjectively correct. I also suspect some higher level measurements would have hinted strongly at what we were hearing. The capability of the mains and specifically center channel largely dictate the useful range of playback levels. The higher in level you can comfortably listen, the less elevation I find justified or desireable in the response, not to mention that you start chancing overdriving the subwoofer prematurely when the mains should be allowed to run a bit louder giving more dynamic impact while effectively yeilding the same low frequency levels as if the sub was set hotter and the system turned down a few dB.


This leads into and somewhat overlaps the third factor, being the capability and characteristics of your subwoofer. The subjective experience is quite different when your subwoofer is running right at its hairy edge vs. your sub running cool and collected. Compression typically comes with other distortions of some form, and it does somewhat audibly identify the limits of the system. The roll-off of the low end also appears to have an effect on the subjective quantity of low frequency energy. An infinite baffle sub or an ultimately sealed system like Jeff's can have very gradual roll-off down to nearly single digits in room. Subjectively, a response curve that overlaps to say 20-25Hz with the reflex design dropping off much faster than the other will sound quite different, and I would probably contour the response of the reflex design a bit differently.


Of course almost all of this predicates having some form of DSP based EQ on at minimum the subwoofer, as well as the means to measure the changes you are making. The in-room response of any un-eq'd subwoofer will likely vary twice this much, and do so much more randomly than many would like to know. In the case of Jeff's system, the real elevation to the response only comes in down quite low with it ramping up somewhere below 40-50Hz. When first setting up the system I didn't and wouldn't have initially put in quite that much of a shelf, but we did find more lift to sound better, yet still appropriate. Had I had the time Chris did to adjust and listen, I likely would have ended up in a similar range. Indeed, it might be a couple dB towards the "fun factor" down low, yet in the few days I was able to listen, there was no sense of the low frequencies rolling over or masking the rest of the range While the bass effects were quite "moving," they were still in scale with the rest of the system (spare maybe the surrounds), as well as the 10' wide image at the front of the room.


Cheers,

 

[John Kotches]

hometheaterguy says:

Quote:

Why imply listener fatigue when there is near zero clipping and distortion in Jeff's system?

I didn't say anything about listener fatigue. I said I would grow tired of the exaggerated first octave response in a week or two. Do you appreciate the difference between the two?.


Quote:

With the Runts playing at that output this would not suggest bass heavy as the system is balanced. DAY AFTER TOMORROW: D-Theater version has been our reference disc as well. Non-stop SPL, aspirin not included (I mean that in a good way).

It's an exaggerated first octave response. It's a user preference, which is fine, but if there is content

John Robert asks:

Quote:

... but why such a huge disparity (15dB) in channel levels?

The LFE channel has a 10dB pad which accounts for the first part. The second part would be the exaggerated response below 30Hz. Here, I am assuming that we're talking about playback at reference levels.


The only time > 10dB difference comes into play is when there is content below 30Hz, otherwise, it's irrelevant.



Jeff (thebland) says:

Quote:

Mind you the subsonic areas of a soundtrack are typically transient and not typically sustained for more than a few seconds at most. My feelings and those I have had over to listen are in agreeance. The bass is unobtrusive.

And my point is that there are other things going on in the soundtrack when the transient occurs that will be obiliterated by the exaggerated response in the bottom octave. It's what you like, that's fine. It's not what I like, that's fine too.


Cheers,

 

[thebland]

John,


I see your point. and it is a fair point!! However, this is where I depart from the ideal (but only a little bit).


John,


If you are ever in the area...I would dig for you to come by and listen first hand. Not that I expect to change your minds but just to chat!

 

[John Kotches]

Jeff,


I will, but I can tell you right now that I don't have anything in the works in your area.


Of course the reverse is true, but I have that crappy Meridian gear and an el cheapo LCD projector to deal with, so you'd have to slum

 

[nirvana_av]

Jeff,


Great thread. Will have to pickup that title.


I'd like to hear some more discussion on sub tuning. Chris, would you have a response curve of Jeff's setup that you could post? I know that Mark mentioned that you should look beyond the measurement but it would be very helpful to see how Jeff's subs are integrated and EQ'd.

 

[pbblair]

I couldn't not chime in...


The +10 on the LFE is almost always handled by the decoder... not by the sub itself. Surround mixes are done with the LFE 10db hot so that it's actually 10db soft in the recoded mix itself. If the decoder boosts it back up 10db, you're back to flat. If you boost the sub 10db, you're 10db hotter than it was mixed.


-Paul

 

[mysphyt]

Quote:

Originally posted by pbblair I couldn't not chime in... The +10 on the LFE is almost always handled by the decoder... not by the sub itself. Surround mixes are done with the LFE 10db hot so that it's actually 10db soft in the recoded mix itself. If the decoder boosts it back up 10db, you're back to flat. If you boost the sub 10db, you're 10db hotter than it was mixed. -Paul

I think the +10dB here is from the THX reference level specifications which call for 105dB SPL at the seat from each satellite and 115dB SPL peak capability from the sub. The -10dBFS that the LFE is recorded at allows for this higher peak capability. Although on second read I think we are talking about the same thing from two different points.