pzaur

pzaur

Audioholic Samurai
I found this graph comparison of the SD DVD and Blu-Ray of Master and Commander. Definitely looks like a 25hz filter being used.

I searched using this keywords: bluray 25 hz

-pat
 
J

jostenmeat

Audioholic Spartan
dem beats, I'm sorry about this tangent. This will be final response here about this, if I can help it, or unless it's you that asks.

Forgive my ignorance, but what is an EQ shelf?
It is simply EQ (boost/cut), but over a wider range. You select the point or center of the shelf for a LF shelf which affects everything below that point. (HF shelf would affect everything above). So, when I chose 30hz as my shelf point with 4db boost, everything below is getting 4db, but above that it attenuates back to flat by 67hz, as far as I could tell.

I didn't notice anything in my EQ that could alter how fast it could attenuate back to flat, which I guess would be called Q. (It looks like Paul Apollonio was just ranting about how too many things are called Q.)

I remember there was discussion a while back (it might have been in one of mike c's build threads), but the idea of using a shelf filter with stereo sub/bookshelf combos, where you can help out the midbass with a HF shelf on the woofer. IIRC.

So on top of my shelf, I was also applying MORE boosts for fun (I get to choose 6 freq's with my Harman Band Manager), and I choose a bunch in the 20-30ish range.

So, what I was saying was that, for whatever subjective reason, the shelf at 45hz was much more impressive to me than the shelf at 30hz, with same 4db boost. Yes, the overall output of the sub is higher, if only in a very specific bandpass, but everything below 30hz (at either setting) was identical. Still, I preferred the 45hz shelf, for whatever reason. I'm probably imagining the greater tactile response, but I liked it, whatever the reason. So, I would not be surprised if all of the "fun" bass was not necessarily down low like 8-10hz. Maybe it is; I still have not been able to get my pants to flap, but I haven't tried too hard to do that either. ;)

I wanted to add (edit), that I preferred the shelf to simply using the receiver gain, where it seemed to be a much greater compromise in SQ. Probably that last bit from 60ish-80ish being left flat probably has to do with that . . . .

Also, if that's true about BD's cutting off at 25hz that sucks. :mad:
Oh well. You know, I can still get things to shake well enough with some scenes in the aforementioned movies. Maybe not WOTW crazy (never bought that one), but . . .

Where did you read this, because Master and Commander's cannon shots sound just fine on my system and I am fairly certain that there is sound well below 25Hz on some of those shots.

I was at a friend's place this weekend and he fired up the THX thingy at the end of Avatar and his subs are geared for 25Hz. There wasn't much there, but mine easily rattles stuff throughout the house.
25 Hz filter on BD DTS tracks?
 
D

dem beats

Senior Audioholic
dem beats, do you know what 8-10 feels like? I don't necessarily know myself, but I've been learning some interesting things while playing with my Crown's EQ on my Danley. I might have read somewhere that B Fitzmaurice, or was it someone else, doesn't even think sub-20 is worth going for.

Anyhoo, I built a big EQ shelf at 30hz, and it didn't have the impact I was looking for. It was like a subtle pressure. Shelf at 45hz, daddy-o! Riser-a-shakin'. And btw, my sub is capable of going pretty low, perhaps not quite as low as the one you're building (though owners have measured usable in-room response down to 7-10hz), but I just wanted to bring up a point/query. IOW, are you sure 8-10 is really the goal to be going for here . . . If your sub is not extremely efficient to begin with, and you're chasing down the lowest subsonics, how much will you be giving up on the usable HT stuff? Remember, a lot of BDs are using 25hz filters anyways . . . . (I've read that Avatar, Master and Commander and LOTR all stop dead in their tracks at 25hz).
I actually have the good fortune of knowing what really loud sub 10 hz feels like. A friend of mine works for a filtration company doing things in which they blast lots and lots of sound at objects untill they break. I got to go into a room with something that reproduces low hz really really loud. Amazing stuff. Had the inner plugs and over muffs. Really cool stuff.

To be clear I can get MORE than enough SPL from my velodyne in the middle of the LFE range. It just sounds like garbage doing it. It definately doesn't like really low LFE. With 2 maelstroms having 10 times the power and more than 4 times the displacement (I'm estimating... I do not know the velo xmax :) ) I will have more SPL than needed for my little theater.

This project is more of an expariment at what it would be like at home to have that extreme low end. With processing I can change where I want emphasis if I need to and where to cut off when I want. Ultimately I think I would like an IB set up, but it's just not an option where I am currently in life so I did this instead.

As for the filter on BD.... Meh. I'm not worried or concerned really. It is more of an exception than a rule. I could also just turn it up "hot" at the sub 25 if I feel the need.
 
Warpdrv

Warpdrv

Audioholic Ninja
Its certainly not all BR's but there are a couple out there that are showing these results, which is a damn shame IMO, but the entire industry certainly can't be bass heads so maybe its been overlooked, but IMO they are def crippling these movies in terms of sheer bass output....
 
j_garcia

j_garcia

Audioholic Jedi
I checked out M&C last night and there is still quite a bit of rumble in there, but I do notice on some of the cannon shots that it feels like some of the infrasonics are missing or lacking. The ones that still sound good are likely higher up, in the mid 20s range, such as the last volley before they head into the fog.
 
D

dem beats

Senior Audioholic
I don't think it's all bad if they reduced the bass a bit, that is if it's a filter applied. If it's them literally removing content... then that's a different thing.

If they scale it back, we can scale it up and run it hot. All the while those that don't have the capacity won't be subject to that horrible pfft pfft noise from their blose system.

Ideally everything would be direct and perfectly matched from an original lossless data format in analog. I personally think it's silly to scale anything back in general, but just like with cars they will neuter the engine to provide a more "middle of the road" expereince. It would be better for everyone if the general consumer was forced to learn how to properly calibrate and make informed decisions, but that ain't ever gonna happen. I think of having bass management like having a chip tuner for a car/truck, to get everything I can out of the original.

I could have a full range true -3db 5hz-22khz speaker at each chanel of my system. Just not realistic for most.

Edit: Also IMO untill someone extracts the actuall audio data and not a waterfall taken from a mic that's in the room playing the audio we can't possibly know if the original track is edited to remove content, or just make certain hz hot and others not.
 
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j_garcia

j_garcia

Audioholic Jedi
I was sort of thinking the same thing. It may be that what we are seeing on those blu-rays is accurate while what we saw on DVD was actually artifacting from the innaccurate lossy tracks before, though the result very well could have been more bass, even if it was artificial.

If they are filtering it, that could be because if they send out discs with clean content down to 20Hz, the vast majority of people out there don't have systems capable of handling that.
 
gmichael

gmichael

Audioholic Spartan
But wouldn't somebody with a BR player be more likely to have a good system than someone with just a DVD player?
 
D

dem beats

Senior Audioholic
But wouldn't somebody with a BR player be more likely to have a good system than someone with just a DVD player?
I would go out on a limb to say that most people who are BD capable neither have 1080p nor more than 3 chan capability.

Even someone who went into best buy and got the best thing they sell couldn't expect to get much bass under 20 hz.

Edit: I know of at least 2 people who have ps3's and actually have them connected to....... CRT. Many think their 720 plasma with built in speaks is the bees knees.
 
j_garcia

j_garcia

Audioholic Jedi
But wouldn't somebody with a BR player be more likely to have a good system than someone with just a DVD player?
Yes, but 20Hz and below capable subs still aren't the norm. I think BD players have become much more common than before just judging by the fact that I can no longer get new release movies on BD from Netflix for a while.

720p is fine for the PS3...for games :) When I bought my first PS3 I had a CRT and it looked good. I upgraded because I wanted it to look better.
 
gmichael

gmichael

Audioholic Spartan
I would go out on a limb to say that most people who are BD capable neither have 1080p nor more than 3 chan capability.

Even someone who went into best buy and got the best thing they sell couldn't expect to get much bass under 20 hz.

Edit: I know of at least 2 people who have ps3's and actually have them connected to....... CRT. Many think their 720 plasma with built in speaks is the bees knees.
I agree with what you are saying and even had those thoughts as I was posting. But I do think that if anyone between the two options (DVD or BR owners) would have a better system, it would be those with the BR. So why do the DVD's have more bass than the BR's?
 
J

jostenmeat

Audioholic Spartan
I agree with what you are saying and even had those thoughts as I was posting. But I do think that if anyone between the two options (DVD or BR owners) would have a better system, it would be those with the BR. So why do the DVD's have more bass than the BR's?
What do you think of what j garcia offered a few posts back regarding the artifacting? That is interesting to me, and I wonder to what extent (both output and extension) that may occur, if at all.

The only other thing I can think of is that it's with after making the DVDs that they figured out people were blowing up their systems, and have no reconciled that with newer BDs? :eek:
 
j_garcia

j_garcia

Audioholic Jedi
It is just like that waterfall of Batman Begins that shows 2Hz! Is that really there or is it a product of when they mastered? It isn't a recorded sound; it was completely artificial, so during the mastering process when they added that sound, I doubt they went in and said "Let's add a 2hz infrasonic tone here for those guys who do waterfall charts." So either they DID add it, or it is a product of the process.

I forget the term, but there is a term for a secondary tone that is a product of the primary one. Something like that?
 
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D

dem beats

Senior Audioholic
Complete narritive

I would guess...... Guess only..... that most of the super sub sonic stuff is on a master audio file is acidental and a result of some form of filtering applied to raw digitily inlaid sounds that then make the synthetic sounds more life like.

All that blending of digital data must create a wicked pile of garbage in the sub 20 hz that is probably unwanted data.

It's kind of like the magins around the camera.... if some wires or rigging are in that it doesn't matter... no one will see it. If it's outside what anyone can replay audio wise... it don't matter.
 
J

jostenmeat

Audioholic Spartan
I forget the term, but there is a term for a secondary tone that is a product of the primary one. Something like that?
Harmonic. I mean, that's what my answer would be if all I read was the quoted portion here.

Harmonics are what makes up the tone of your voice, anything. It's what separates the sound of a clarinet and a violin. Even among the same group of instruments, say a piano, some will be clearer (much more fundamental, with less harmonics), and some will sound warmer with more harmonics, but at the expense of clarity.
 
gmichael

gmichael

Audioholic Spartan
Harmonics was what I was thinking too. When you have two sounds at different frequencies, another sound is created that is the difference between the two original sounds. Could that be the cause? And that's why a filter was added?
 
j_garcia

j_garcia

Audioholic Jedi
Harmonics was what I was thinking too. When you have two sounds at different frequencies, another sound is created that is the difference between the two original sounds. Could that be the cause? And that's why a filter was added?
That is exactly what I was getting at; possibly in the processing, that stuff is actually junk and on the BD they are filtering it out.

Harmonic. I mean, that's what my answer would be if all I read was the quoted portion here.

Harmonics are what makes up the tone of your voice, anything. It's what separates the sound of a clarinet and a violin. Even among the same group of instruments, say a piano, some will be clearer (much more fundamental, with less harmonics), and some will sound warmer with more harmonics, but at the expense of clarity.
YES! That was it.
 
pzaur

pzaur

Audioholic Samurai
I think the term you're looking for is a resultant. Different intervals played together create different resultant pitches. They can be higher or lower.
Here's a better, more technical definition.
It's a very cool effect that is easily heard in duets and can make it sound like a third individual has joined in.

-pat
 
gmichael

gmichael

Audioholic Spartan
Back when I still played, we used to use it to tune a guitar. Strike two strings in such a way that they should be making the same note. If they do not match, you can hear the harmonic (or resultant?). A little adjustment one way or another until it is gone will tune those two strings to each other. As you get closer to the right tension, you can hear it slow down and then stop.
 

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