I have two words for you...Bass Management UPDATED! (1 Viewer)

[David Tallen]

I have tried to keep up with this thread, so I apologize if this has already been answered, but can someone explain the advantage of setting full range speakers to "large" in a system that also has a capable subwoofer? (I am talking about speakers that really are full range. I realize that not many are.) I understand, technically, what happens, but what is the advantage to the listener? Is it simply that such a setup adds some intended directionality to the bass that would be lost if it came from the sub? If so, is this really noticeable? Is there another reason?
I would like to thank all of the contributors to this thread, and Obi, particulaly, for starting it. As one who freely admits to knowing very little about bass management, this thread has been a gold mine.

 

[Jim A. Banville]

>>>I have tried to keep up with this thread, so I apologize if this has already been answered, but can someone explain the advantage of setting full range speakers to "large" in a system that also has a capable subwoofer? (I am talking about speakers that really are full range. I realize that not many are.)

 

[Ned Vogler]

Should I preface by saying that I'm really glad to have JP on DVD? And that I enjoy both DD and dts in my HT? A resounding YES to both. My reply to (as well as my reason for reading this thread) is based purely on curiosity...well OK, and the fact that I enjoy a good debate.

Vince said -


Quote:



As it was, with JP on the 3 formats (we dropped the idea of making it 4 formats by including the the PCM laserdisc version before even starting) we demoed 5 scenes, and then spent time doing some back and forth scenes between just the DVDs and it took over an hour to complete!






and William D. Cavender said:


Quote:



I will be brief. My gear is primarily Meridian and I measured the first three drum beats and the first dinosaur stomp from three diffrent sources of Jurassic Park with my Radio Shack sound pressure meter, each source was measured three seperate times.





I would be interested to see the results of test using ALL 5 formats of JP on LD/DVD: the DPL PCM LD, the DD LD, the dts LD, the DD DVD and the dts DVD. I endeavored to do this over the weekend, but I realized I had sold my DPL PCM LD of JP!

I did do some layman comparisons between the DD LD, the dts LD, and the dts DVD (I haven't received my DD copy of JP on DVD yet). The reason I say these are layman comparisons is that I'm not sure where to set my receiver volume for the different media and/or sound format in order to make the sound levels "equal". I also wasn't sure which weighting and response to set my SPL meter to, not to mention which number setting. I initially started by setting my receiver (Pioneer VSX-27TX) to -31db for the dts sources and -27db for the DD sources to compensate for the dialog normalization of DD. I was setting my SPL meter to 80 which was allowing me to read settings from 70 to 90 SPL and using C weighting and fast response. BTW, I have the DIGITAL RS SPL meter, and I know that is another whole discussion entirely.

Anyone care to offer any suggestions on specific settings/levels for both receiver and meter needed to compare all these discs fairly?? Anyone else with a bit more know-how willing to volunteer?? I am certainly willing to compare further, I would just like to make sure I am doing so in the correct manner.

I am also curious to find out how the new DD mix on the DVD compares to its LD counterpart since most of the discussion in this thread has been comparing the DD DVD vs. the dts DVD or the dts DVD vs. the dts LD. TerryC are you listing?

 

[Vince Maskeeper]

Anyone care to offer any suggestions on specific settings/levels for both receiver and meter needed to compare all these discs fairly?? Anyone else with a bit more know-how willing to volunteer?? I am certainly willing to compare further, I would just like to make sure I am doing so in the correct manner.

To be honest, if it is the same for all formats the metere Weighting shouldn't matter. One setting ignores bass freq and the other doesn't: but if you're testing each disc in relation to each other, as long as you use the same setting you should be OK.
I would recommend using more mellow passages from the film. I didn't want the possibility of a slightly juiced LFE channel to cause the DTS LD to be reduced in volume to the point where it was quieter. As a result, I tried to use dialog driven or music cues to test the relative levels.
The speed setting on the meter should probably be set to slow, just for your own ease. But once again, as long as it is the same for each it shouldn't matter to much: the slow setting allows you to get more of an RMS average without the meter jumping around on peaks. this should be especially helpful since you have a digital meter which is notoriuosly difficult to read.
As far as receiver settings go, make sure the LFE pad settings are correct. You may need to consult your manual to know where the settings are and where they should be. I would say make sure that the DD LFE pad is set to 0 if your system lets you choose between 0 and -10 or +10 if your options are 0 and +10.
After making sure your LFE pad for DD is correct, double check your relative levels with a test disc like VE or Avia. Get calibrated to ref level.
Then check to make sure your DTS LFE pad is correct. Again, this may require consulting the manual, as I'm not sure this is as standard as the DD lfe pad issue (Does anyone know of the LFE on DTS is encoded -10db like DD? I assume it is, but have never confirmed...)
Now, as long as your meter weights remain the same, you should be able to test a short section from the film (say, 5 seconds). I started with the DD DVD, since I had calibrated to DD ref level using a DD DVD (Video essentials).
Adjust you meter's level dial until your readings are near 0 (this is for the analog meter, I think it operates the same for the digital meter). It will probably end up at 80db setting for most dialog passages at ref level.
Determine the level of the 5 second passage. After looping a few times, you should be able to pretty much memorize the behavior of the meter with each word or music cue. Switch to another format (say the DTS DVD) and play the same 5 second loop and measure from the same position (placing the meter on a tripod will help free you up to switch discs and still measure from the same spot). You should be able to determine if it is louder or softer than your previous readings. Adjust the volume until you achieve the same meter readings as previously.
By doing so with several 5 second sections, you should be able to get very close to level matching (within 1db average I would say). It's tought to get it perfect, especially when desling with different mixes: I've found that you may find one scene is 1-2db louder while the next is 3-4db louder.
-Vince
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[Wayne Bundrick]

Vince, the LFE on DTS is supposed to be encoded for 10 dB of extra headroom just like Dolby Digital. It isn't a Dolby standard, it's a SMPTE standard. No doubt Dolby had a lot to do with it becoming a SMPTE standard, as Dolby was involved in the creation of the subwoofer channel on 70mm film back in the '70s, but that doesn't mean DTS should refuse to adhere to it.
However, it seems that DTS does not use 10 dB of extra headroom on the subwoofer channel of DTS music CDs and possibly DTS music DVDs. For these the decoder is not supposed to provide the 10 dB boost. I don't own enough DTS CDs or DTS music DVDs along with their corresponding PCM versions to say for certain that this is always true, but the manual for my Denon receiver recommends the LFE setting be set to 0 dB for DTS movies and -10 dB for DTS music.

 

[Timmy]

Jim A. Banville
I've tried to say that exact same thing before... and with an entire page didn't acheive what you wrote in just a few sentences.
An excellent (and accurate) answer!

 

[Robert Holloway]

Reality check guys
I went round to a friend's house on Saturday night
He had bought a very nice HT
Toshiba 56" monitor
Velodyne sub
B&W all round
So good so far
he chose to demo it with a DTS disc from The Eagles
Put in the disc
Pressed play
Then
Went to preamp and turned up the LFE/bass to maximum
Sounded awful!!!!
Desperado, boom, .......
Robert

 

[EricK]

Last night I did a comparison of 4 different versions of Jurassic Park. We compared the opening scene of the raptor in the box being loaded into the cage.
DTS DVD: we both agreed that it was very harsh, and bright. We both agreed that the bass was not as good as it could have been.
Dolby Digital DVD: we both agreed that the bass here was an improvement on the DTS DVD but could have been better still. The track itself was even harsher and brighter then the DTS DVD.
Dolby Digital LaserDisc: we both agreed that the harshnees and brightness had gone away! The bass was deep, and shook you when the Raptor attacked after the gate opening.
DTS LaserDisc: we both agreed that this disc was sweet. However the rears were definitely a good +3db over any of the other versions. But even with that, the DTS soundtrack was absolutely sweet. Bass was punchy and it hit hard. There were no signs of harshness or brightness. I felt that even with the rears being a bit higher, the DTS LaserDisc blew all other versions away.
Therefore, I will continue to hold fast by my original conclusions. The JP DVD's are HORRIBLE! They could have been done so much better, but I guess we will have to live with them. All I know is I may try to find a copy of JP DTS LaserDisc.
Eric.

 

[WilliamC]

Jim and TerryC:
I was unaware that even though a speaker is rated as being able to go to a certain frequency that they volume may vary so much. Thanks for the information. I will try mines out later on to see what results i get. the volume should remain the same at all frequencies correct? If not what volume would be the optimum for the lows?
thanks,
William C.

 

[Scott O'Keeffe]

Actually, Jim gave the answer to David's question as if the question was asked "What is the advantage of setting the speakers to small..."
David wanted to know why some people set their speakers to large when they have a capable sub.
But, I agreee, Jim did give a nice explanation to why you set your speakers to small. Or at least why I do.

So, I have the same question...why do some ppl like to run their mains large when they have a more than capable sub? A sub, in most cases, will be much more proficient in producing low bass. Sure, some mains CAN do it, but I think running speakers small has more advantageous qualities.
So, large crowd, can you fill me in here?

 

[TerryC]

William C,
You are right about how each frequency "should" be all the same loudness. Trouble is that its hard for any speaker to do, but it IS the ultimate goal. Some of the problems are room modes and nulls which can really effect the results as well as speaker inefficiencies. I suggest you test your speaker at about 1 meter distance and hold the mic about 12-16" off the floor at a slight upward angle. Set your volume to reference level(you might try -10db or -15db if reference level is way to loud and causing stress to the speaker) and run a frequency sweep and record the results. You can use Avia but it goes really fast so its hard to keep track of what each frequency measured. You can down load a MP3 I set up if you have a CD burner. Burn it as a wave file so you can use it in your CD player and it will make this process much easier as each frequncy lasts for 5 seconds
.
Here is the MP3 sweep: Its 15 to 80hz one hertz increments that are each 5 seconds long. http://terryctheater.tripod.com/15to80sweep.mp3
Also be aware that the Rat Shack meter isn't too effective measuring low frequencies. Add these numbers to the measurements you recorded at each frequency to compensate for it.
16Hz add 11.5
20Hz add 7.5
25Hz add 5
31.5Hz add 3
40Hz add 2.5
50Hz add 1.5
63Hz add 1.5
80Hz add 1.5
100Hz add 2
Let us know the results.
Terry

 

[Philip Hamm]

I just want to thank everyone who has responded on this behemoth thread, particularly Vince. Lots of great information here. I am planning on hosting another Northern VA HTF meet at my house sometime in the next few months, and then we can A/B the DD LD andeither DVD through my system and see what happens. I look forward to doing this experiemnt.
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Philip Hamm

Rock over London, Rock On Chicago, Mitsubishi, the word is getting around.

 

[Timmy]

why do some ppl like to run their mains large when they have a more than capable sub? A sub, in most cases, will be much more proficient in producing low bass.

If you re-route the LFE to the mains (with no sub) you risk over taxing the mains to take on this extra duty.
Same thing with a "small" configuration and a powered sub. You are now sending more bass info to the LFE connected sub than originally intended. Can it handle it? Well, only your ears can detect possible boomy or distorted bass from an over-burdened sub.
Even though I set my sub to reference level (a very capable Velo 15" LFE sub with 300w-rms amp) I noticed more boominess and distortion (on a few "taxing" movie scenes) and had to turn it down below reference to clean things up. I recently replaced my mains where the new ones extended down further, reconfigured them as LARGE, re-cal'd the sub, and it gave much more cleaner and tighter bass..... and I am now able to leave the subs level at reference.
This was best for my specific setup.... yours may be different.

 

[Scott O'Keeffe]

Timmy:
Certainly not trying to start a major debate here, but I don't know if I'd be too concerned with "reference." If I had to turn my sub up or down to compensate for any difference, I'd rather do this than possibly overtaxing the midrange performance of my mains. I'm sure this is not a major concern for people with higher end speakers (which could be you), but this could be a problem for those with average speakers. I'm definitely no expert, but it seems to be a cleaner, fuller sound when I'm set to small. You are right though, sometimes you will suffer from boominess, but if I play that type of movie, I adjust the level of the sub (or LFE setting) and go from there.
But, like you said, its what sounds best in your set up.
I think we're running into that a lot here.

Denon 3300
BW 602S2 mains (wonder why I'm set to small??)

BW LCR Center
JBL 610 rear
BW Sub

 

[David Tallen]

Timmy, can you explain exactly what you do to set your sub to reference? I am not challenging you; I really am not certain that I understand the process. When I adjusted my speakers using Video Essentials, I set the receiver's volume control so that the VE reference tone registered 75 dB on the fronts, center and surrounds. Then I set the sub's volume control so the reference tone registered 75 dB on the sub. I understand that sometimes 85 dB is used as the reference volume level, however, in my small room, 75 dB was plenty loud enough. Actually, I rarely crank up the volume to that same level when I am actually watching a movie; it's too loud for me.
Unless I've got the whole process wrong, I assume that you do something similar to adjust the volume on your system. Once you have adjusted the volume using reference tones, do you leave the volume control at that level (75 or 85 dB) when you watch movies? If I did that, I'm not sure what would go first, my ear drums, my speakers or my windows.
I hate to display my ignorance, but I am trying to learn how to properly adjust my system, and I appreciate the input from those of you who have so much more experience.

 

[Timmy]

Somewhat off topic
David, I use Avia for my audio calibration. IMO it does a better job with the LFE calibration. I did match my subs level to within my entire speaker system. And like you, with my receivers volume control set to "reference" volume, it's just overall too-loud on certain passages for my tastes. To correct, I activated my receivers "dynamic range compression" feature to "level-off" these loud passages, and it works well EXCEPT when playing music. Dynamic Range compression ruins music. And then I've tried to not use DRC and just lower the volume a little; and with some movies this seems to be the better method (than DRC).
Don't feel weird just because you have decided to stray away from a reference calibration..... I certainly don't hesitate to "tweak" just after an alignment (to suit my particular tastes); even though some would think doing this is blasphemy

 

[EricK]

Philip,
I'd love to be involved in that HTF meeting! I may be down in Bethesda, MD. at the same time you are planning your meet! Please let me know....would love to meet you and some other fellow members!
And I'll even bring some software if you'd like!
Eric.

 

[AnthonyL]

Question: I have a Yamaha 2095. I can set my LFE anywhere between -10 to +10. I originally left it at -10. But ever since I got my DTS JPk DVD I bumped it to 0. Anyone(especially Yammy 2095 owners) know where I should set it at?

 

[Vince Maskeeper]

I am planning on hosting another Northern VA HTF meet at my house sometime in the next few months

Philip,
Looks like I'll be in Ashburn, VA (near Reston) for the Thanksgiving Holiday (Tues-Sunday) and then again in early January...
If you plan to have some happenings in that ballpark, let me know!
-vince

 

[Clinton McClure]

TerryC,
Sorry it's taken so long to respond. Out of town all weekend...just got back today.
The room is 17' deep, 27' wide, and 9'tall at peak. The ceiling is 7' at the outer walls and gradually works up to a 9' peak.
The HT is set up so that the viewers are facing one of the 27' walls. (The room is wider than deep.)
There is a doorway between the monitor and the left main. ALso there is a doorway behind the listening position on the left side and another doorway behind the listening position on the right.
I found the 75dB setting with the receiver-generated pink noise. (I think I've been calling it white...I've heard it both ways and sometimes call it both ways.) The dial is a little above 11 O'clock. This in itself is not as interresting as the surround levels.
When I calibrated with VE, I had to do some adjustments on the surrounds to make them match the mains and center. Using the internal pink noise on the receiver, the left surround was 78dB and the right surround was 76dB.
I think something which might help explain the 116 a little more, is that it isn't all LFE. The Radio Shack SLM (Sound Level Meter) I have is used to measure LFE or other sound, yes? I'm more familiar with SPL (Sound Pressure Level) meters used specifically to measure bass in car stereo events. (I've done a couple myself over 140dB on the dash.) The dB peaks I was hitting in my HT were not all LFE. A lot of it was action sequences, not necessarily very bassy. Mostly what was being measured were mids and highs. Very crisp, very clean, very loud.
It looks like we might have been measuring slightly different things if you were just measuring LFE.
By the way, the graphs do explain a lot in relation to the differences in monitored LFE on soundtracks. Very interesting. Thanks for sharing and I'm looking forward to your findings on DTS JP.
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No, that's just what they'd be expecting us to do!