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Bass Management in Blu-ray Player

Scott Wilkinson  |  Jun 22, 2012

I am contemplating a 4.0 setup with two subs in the left and right front speakers using just the bass management of an Oppo BDP-95 Blu-ray player. If I set the left and right front speakers to Large, is the LFE channel redirected and divided between the left and right front channels? Can the center channel be totally re-directed and divided between left and right front? If the surround and back left and right speakers are set to Small, can the low frequencies from those channels be re-directed to the left and right front? Finally, can all these conditions be met simultaneously?

Michael Soderback

I double checked with Oppo and confirmed that if you set the subwoofer output to Off and the front left and right speakers to Large, the LFE is redirected equally to the front left and right outputs. Similarly, if you set the center-speaker output to Off, the center channel is divided equally between the front left and right speakers, a configuration known as a phantom center. And if you set the surround speakers to Small and the fronts to Large, the low frequencies in the surround channels is redirected to the front left and right.

As for whether or not you can do all these things simultaneously, the answer is a qualified yes. When the center channel is turned off, the back-surround channels are also disabled because of a limitation in the unit's DSP. The side-surround channels can still be active, so turning off the center channel will support a 4.0 or 4.1 speaker layout, but not 6.0 or 6.1. In this case, the back-surround channels are folded into the side-surround channels, so you won't miss anything in the soundtrack.

I'm curious about why you want a 4.0 system with no center speaker. I know several audiophiles who opt for a phantom center when listening to movie soundtracks, but I strongly prefer a real center speaker, which anchors the dialog to the screen much more than a phantom center. A real center speaker also provides better imaging with movies and multichannel music, though some would argue that a horizontal center speaker is inherently compromised and it is therefore better to use a phantom center for music.

If you have an A/V question, please send it to askhometheater@gmail.com.

COMMENTS
mailiang's picture
Submitted by mailiang on June 22, 2012 - 4:18pm

I have to agree with Scott. Why not use a designated center channel speaker? My other question would be is why are you using the bass management in the BD player and are you currently driving your system with a prepro set up or AVR?

Ian

Scott Wilkinson's picture
Submitted by Scott Wilkinson on June 22, 2012 - 6:09pm
Good question about why he's doing the bass management in the player.
skydogdoug's picture
Submitted by skydogdoug on June 27, 2012 - 5:57pm

I applaud Mike for experimenting with his sound management tool box. One of the aspects of audio I enjoy is the tinkering with tone and bass is a tough one to dial in. My sub-woofer bass was dull until I lifted it off floor with my wife's tea light candles. My MMG-W power pig Maggies didn't light the room until I used my Jolida 302A to power them. Use your tool box and when you achieve sound nirvana let us know how you got there.

techguy378's picture
Submitted by techguy378 on June 23, 2012 - 2:34am

Probably because they're using an older receiver that doesn't support newer Blu-Ray audio formats. As for the lack of a center channel speaker, no clue.

mailiang's picture
Submitted by mailiang on June 23, 2012 - 4:06pm

Just my 2 cents, but I don't believe there is any good reason to use the player's analog outputs unless your receiver is so ancient that it doesn't have a digital input. Most Blu-Ray players, even the high end ones like the Oppo's lack the bass management flexibility that is found in most prepro's and AVR's today. Also, the LFE channel which is calibrated to run 10db hot, is attenuated by 10db to prevent over load to your receiver's analog inputs. This can have a negative impact on over all bass output when watching movies. Converting digital to analog audio is far more critical then going from lossy to lossless audio formats when it comes down to over all sound quality.

Ian

techguy378's picture
Submitted by techguy378 on June 24, 2012 - 2:18am

In most cases you're correct, but you're completely wrong when it comes to super audio CD's. I once had one of Sony's first budget SACD players. It didn't have an HDMI output, only a six channel analog output. The player came with a demo SACD disc from Sony that had four songs that were originally done in DSD, not PCM. I now have a newer Sony BDP-S70 SACD player hooked up to my receiver via HDMI. I can tell you that the older Sony player's analog outputs sounded far better than using HDMI to convert DSD to 176.4KHz PCM to analog. My small bookshelf speakers and subwoofer aren't even at equal distances from my listening position.

mailiang's picture
Submitted by mailiang on June 25, 2012 - 8:55pm

I wasn't posting about Super Audio CD's. I was referring to Blu-Ray's bass management, which is more critical in terms of sound quality, in comparison to lossless verses lossy HT audio applications, since it is and should remain, strictly a digital format.

Regards,
Ian

yachtmandu's picture
Submitted by yachtmandu on June 22, 2012 - 4:46pm

LFE's are non-directional. What speakers do you have? Can they pull down below 30 hz with authority? A phantom center channel goes well with an LCD, as you move off axis, the sweet spot, the audio deteriorates along with the picture. Consider a center channel and a plasma. And always remember, sub-woofers are for Hondas and not for those that can afford real speakers.

Scott Wilkinson's picture
Submitted by Scott Wilkinson on June 22, 2012 - 6:08pm
Good point about the sound quality of a phantom center deteriorating as you move off-axis. However, I disagree that subs are for Hondas and not for "real" speakers. Even if your main speakers go down below 30Hz with authority, the best placement for the lowest-frqeuency drivers in a room is often not the same as the best placement for the higher-frequency drivers...not because of directionality, but because of room modes.
Santeini's picture
Submitted by Santeini on June 22, 2012 - 9:04pm

For home theater, a powered sub is a must.Most reciever will not be able to drive the main speakers,with full potential at 30Hz.Futher more if you let the sub to handle the bass, your reciever will have more headroom to drive the rest of the speaker.(all your speakers low frequency must be crossed over to the sub)

mailiang's picture
Submitted by mailiang on June 22, 2012 - 9:08pm

I have to agree with Scott. Most quality dedicated subwoofers will out perform even larger full range speaker systems when it comes to reproducing the lowest bass frequencies, especially if they are placed properly. Since they have their own power source, they also reduce the load on your Amp or AVR. Less load means more headroom, less distortion and better sound quality.

Ian

yachtmandu's picture
Submitted by yachtmandu on June 23, 2012 - 8:52pm

You all have good points. But, there are some of us who have mains that pull down below 20 hz - and even a quality sub just gets in the way and can't keep up. As for headroom and less load on the mains - I call crap. I run a trio of old school Luxmans as pre-amps. They have transformers the size of bowling balls and at 35 watts, real RMS, do just fine delivering enough power to launch a Saturn V. Mind you the mains are custom built JBL/Altec two way hybrids the size of a washer and dryer and weigh in at about 250 lbs each - they are pure evil. Matching these for timbre with a center channel was an expensive hellish task that ended with a pair of JBL's from the 80's. Anyhow, I'm off topic...bass management can be a long weird road especially if you don't have a reference point. Go with your ears and always remember...you can always use a pair of Hondas as mains and their subs to deliver bottom end. Good luck.

mailiang's picture
Submitted by mailiang on June 23, 2012 - 10:04pm

Most home theater systems today make use of separate subwoofers which as Scott mentioned can be strategically placed to optimize deep bass performance. Also, if you shop around, there are plenty of powered subwoofers these days like those from Velodyne, HSU , SVS, JBL and countless other manufactures that will reach well below 20hz with enough authority to impress even you! Lol.

yachtmandu's picture
Submitted by yachtmandu on June 24, 2012 - 1:38pm

as we say in the biz...below 30hz there is no law - below 20 there is no God. yes, there are plenty of subs that can pull down below 20...but they all have a flaw in that they sound separate rather than integrated with the overall sound wall. speaker builders created subs to sell you separate speakers: period. i wouldn't trade my washer and dryer size boxes: JBL wide dispertion horns, Altec 20 inch long throw drivers, 30 inch passive radiators, Neve tube pre-amp (thank you Mushroom Studios), luxman speaker amps, and a vintage WEM contoller for anything you can deliver under 100k. i'll take you below 20 hz in a way you can't imagine...lol.

Santeini's picture
Submitted by Santeini on June 25, 2012 - 8:58pm

Almost all theatres uses sub.Your statement may be true for stereo listening,but when comes to home theater it's a different ball game.

mailiang's picture
Submitted by mailiang on June 24, 2012 - 1:49pm

When are you inviting me over? Lol.

Ian

yachtmandu's picture
Submitted by yachtmandu on June 24, 2012 - 3:02pm

the wife says i should start an audiophile website and call it
e-harmonics...poor guy on the original post is wondering...should we tell him the truth or sign him up for the home theater cruise?

Stosh's picture
Submitted by Stosh on June 27, 2012 - 2:24pm

Back in the 1970's, long before anyone used the term "home theater", I set my TV between my stereo speakers and hooked them up to the TV. It worked fine; no one ever complained that the sound didn't seem like it was coming from the TV. In fact, it did, due to the "phantom" effect.

I currently do have a center speaker in my 5.1 setup, but I would have no problem eliminating it if it became necessary for some reason. My Vandersteen speakers do a great job of diffusing the sound so it doesn't obviously come at you directly from the speakers, so even people sitting off-axis would still hear the sound as if it were coming from the TV itself. In fact, that happens now with two-channel music.

I know it is sacrilege to say such things, but center speakers are the most expendable of any in a surround system.

mailiang's picture
Submitted by mailiang on June 27, 2012 - 8:04pm

I respectfully have to disagree with your analogy. The center channel is probably the most important speaker when it comes to a home theater system. With stereo sources, sound is mixed to the left and right channels equally, that way vocals can create the phantom imaging you speak of. However with films and multi channel programming, most of the the dialog/vocals and many of the effects which are often centered on the screen, are specifically panned to the center speaker. Even if the center channel is down mixed to the mains, pin point imaging and the over all surround effect is reduced quite significantly. If you find that your current 5.1 set up is not producing the results that you should expect, you may not have balanced out your system properly

Ian

StreamerFan's picture
Submitted by StreamerFan on October 18, 2012 - 2:08pm

I prefer a 4.1 system with no center. Phantom center works great for me. Dialog is clear and locked to where actors are on the screen, and stays locked even if I move around the room, the person who is talking sounds like it.
My speakers image well, (you can't look at them and tell sound is coming from them exactly) and are pulled out from the wall, as is the flat panel. This might not be doable for everyone.

I have found just the opposite to your findings, that is difficult to get a center speaker inline with the front surrounds tweeter and the flat panel. Either the TV is higher than I'd like or the center is lower and out of tonal alignment. It is easier to align 4 surrounds for height and depth and set the tv panel right into the soundstage where I want it. With this I get exceptional surround and save on the cost of the center.

I have the surrounds set 6db lower than the fronts which not only blends them well, but also hides their location from detection.

If the center channel is lacking, it may that that it needs to be bumped up in relation to the fronts, and then it should stay locked.

My own finding is that voices move around the screen and with stereo they float around better than being locked to a center.

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