Localized Bass?

[herbu]

A couple threads started me thinking about this lately. Thought I understood, but further reflection generated some questions.

Say you have a 2.0 system. All bass goes to either the Left or Right channel. If the tone is above ~120Hz, you can determine if it's coming from the L or R. If it's below ~120Hz, you can't.

Now you go 2.1. Once again, if the tone is above ~120Hz, you can determine where it originates. Below ~120Hz you can't.

So all the cautions about localized bass w/ a high crossover really mean the high bass sounds like it's coming from the sub rather than the Left or Right. Either way, it's localized... just from a different location, depending where you put your sub(s). Right?

For ADTG, with a sub under each speaker, it wouldn't matter. For the guy who puts his sub(s) near his L or R, it wouldn't matter. Right? So localized bass with a high crossover may only be a consideration for the guy who has his sub(s) far separated from his speakers... like in back of the room. Right?

 

[TLS Guy]

A couple threads started me thinking about this lately. Thought I understood, but further reflection generated some questions.

Say you have a 2.0 system. All bass goes to either the Left or Right channel. If the tone is above ~120Hz, you can determine if it's coming from the L or R. If it's below ~120Hz, you can't.

Now you go 2.1. Once again, if the tone is above ~120Hz, you can determine where it originates. Below ~120Hz you can't.

So all the cautions about localized bass w/ a high crossover really mean the high bass sounds like it's coming from the sub rather than the Left or Right. Either way, it's localized... just from a different location, depending where you put your sub(s). Right?

For ADTG, with a sub under each speaker, it wouldn't matter. For the guy who puts his sub(s) near his L or R, it wouldn't matter. Right? So localized bass with a high crossover may only be a consideration for the guy who has his sub(s) far separated from his speakers... like in back of the room. Right?

Well, yes and no. The output from the LFE channel is mono even if there are two sub outs.

It is best to have the lowest frequencies mono as that excites less room problems.

However if you have a high crossover, even with the speakers adjacent you will upset imaging.

I have to say when I hear demo systems I seem to know darn well were the bass is coming from.

I'm far from certain that subs locations are that obscure, unless you have a lot of them.

I honestly have to say that I find my integrated system much more realistic. The frequencies below 60 Hz are mono, not the rest.

The other issue is that even with a fourth order crossover at 60 Hz the output only gets to total insignificance at 120 Hz.

 

[lsiberian]

Your results are going to vary for each room and system, but I think the ideal bass system is either 4 corner loaded subs or TL mains capable of 20hz extension. That said a well placed single sub does a very good job. Multiple subs and deep extending TLs are the dreams of audio systems, but aren't always practical for a space or budget. If you want to see how good a placement is simply pick up a measurement mic and try your subs in each available spot.

 

[herbu]

Thanks, guys. But I'm still not sure...

First, let's forget LFE and consider just the bass in your L/R channels. It's difficult for me to localize the bass in music, even bass heavy music.

I have one sub in front and one in back. Playing w/ sub volume and crossovers, it's hard for me to localize Left to Right, or front to back.

Maybe it's just me. But I wonder how much of an issue "localized bass" really is in determining your best crossover. Maybe your determination should have more to do with your speaker and sub capabilities... then if you notice a localized bass issue, you can back off. Is it something to be aware of, but not to really worry about under normal circumstances?

 

[sterling shoote]

Of course you can experiment with crossover, as well as bass volume. My experiments suggest over all that movie sound effects are more to my liking with sub integration. However, with most music in my collection, including a lot of dance/house stuff, things just sound better with the sub turned off. I do have some pretty good 3 way main speakers which I'm certain reproduce most bass present in my music collection so the sub really adds nothing but exaggeration.

 

[herbu]

I do have some pretty good 3 way main speakers which I'm certain reproduce most bass present in my music collection so the sub really adds nothing but exaggeration.

I have "pretty good" mains too. Not talking about preference for music listening w/ or w/o subs. Can you tell if the bass guitar is coming from your Left or Right speaker in most music?

 

[sterling shoote]

I have "pretty good" mains too. Not talking about preference for music listening w/ or w/o subs. Can you tell if the bass guitar is coming from your Left or Right speaker in most music?

What a great question. Interestingly, I just listened to Fleetwood Mac's Rumors SACD. One song, I can't remember which at this moment had a bass guitar riff that was quite notable. Thing is, I was listening to the piece while relaxing on a couch at the right side of my listening room, so I do not know if the bass was at all directional. When I get home tonight I'll listen from center stage and get back to you.

 

[TheWarrior]

A couple threads started me thinking about this lately. Thought I understood, but further reflection generated some questions.

Say you have a 2.0 system. All bass goes to either the Left or Right channel. If the tone is above ~120Hz, you can determine if it's coming from the L or R. If it's below ~120Hz, you can't.

Now you go 2.1. Once again, if the tone is above ~120Hz, you can determine where it originates. Below ~120Hz you can't.

So all the cautions about localized bass w/ a high crossover really mean the high bass sounds like it's coming from the sub rather than the Left or Right. Either way, it's localized... just from a different location, depending where you put your sub(s). Right?

For ADTG, with a sub under each speaker, it wouldn't matter. For the guy who puts his sub(s) near his L or R, it wouldn't matter. Right? So localized bass with a high crossover may only be a consideration for the guy who has his sub(s) far separated from his speakers... like in back of the room. Right?

If you can localize a subwoofer, you need to turn the gain down. If you can localize a pair of stereo speakers, you have lost the precedence effect that creates a single image to the listener, from a pair of speakers. If this occurs, you need to adjust the arrangement of speakers to the listening position(s).

Is this what you are getting at?

 

[herbu]

If you can localize a subwoofer, you need to turn the gain down. If you can localize a pair of stereo speakers, you have lost the precedence effect that creates a single image to the listener, from a pair of speakers. If this occurs, you need to adjust the arrangement of speakers to the listening position(s).

Is this what you are getting at?

Kinda. In threads about crossover settings, the point of "localized bass" with a high crossover is made. I'm thinking the higher bass frequencies that can become localized to your sub(s), are already localized to your front Left or Right... unless they're mastered equally to each. Your precedence effect.

And in the case of most music, in stereo w/o a sub, I can rarely detect that the bass is coming from my Left or Right. Voices, guitars and pianos, yes. Bass, no.

So I'm thinking either the bass is mastered to both channels, or normal bass (guitar) frequencies are too low to localize.

 

[AcuDefTechGuy]

Like already mentioned, the correct answer is always "it varies".

It's not black and white.

I have a total of 5 subs under my 5 speakers. My XO was 120Hz. I couldn't tell any ADVERSE "localization" or image effects even when I'm actively listening for it.

 

[TheWarrior]

So I'm thinking either the bass is mastered to both channels, or normal bass (guitar) frequencies are too low to localize.

When you say 'localize' above, are you just saying that you feel that you are lacking bass and are unable to hear it?

As always, a post on this forum, to me, means someone is seeking advice for the best possible sound quality. So it sounds like you know that there should be bass, where there isn't, correct?

 

[sterling shoote]

I have "pretty good" mains too. Not talking about preference for music listening w/ or w/o subs. Can you tell if the bass guitar is coming from your Left or Right speaker in most music?

O.K. I just listened to Fleetwood Mac's The Chain from the Rumors SACD. The bass guitar is well centered on the sound stage with or without my subwoofer. My subwoofer added nothing more than a sense of it being present, which is what I expected. It's set at about a 85Hz crossover.

 

[TheWarrior]

O.K. I just listened to Fleetwood Mac's The Chain from the Rumors SACD. The bass guitar is well centered on the sound stage with or without my subwoofer. My subwoofer added nothing more than a sense of it being present, which is what I expected. It's set at about a 85Hz crossover.

That is very good, but your room is different from Herbu's. And when it comes to frequencies below the transition frequency of the room (which is different from the Schroeder frequency as this does not pertain to recording studios) means that room modes, and standing waves, will greatly influence what Herbu is hearing at the Listening Position.

But without measurements, Herbu is flying blind. We cannot know what is really going on at that LP!

As to the comment of 'pretty good mains': that is irrelevant because of the influence the room has on those speakers. The best speakers, in the worst room, will sound mediocre, at best!

My Phil 3 review did not include measurements due to the fact that the shape of my room left much to be desired at the LP, despite my ears not indicating anything was missing. After implementing quad subs, thats a different story!

 

[herbu]

When you say 'localize' above, are you just saying that you feel that you are lacking bass and are unable to hear it?

Nope, not at all. "Localized" means you can tell where the sound is coming from. Is it coming from your Left speaker? Right? Sub?

In many stereo recordings you can clearly hear maybe the singer coming from the Left speaker. The recording was mastered this way, and you can clearly "localize" the specific sounds.

In some threads about crossovers, it is mentioned if you set your crossovers too high, you can "localize" bass frequencies... meaning you can begin to tell that the bass is coming from your sub rather than your L/R. This is what I'm wondering about.

I don't recall ever detecting that the bass guitar is coming from the Left or Right. Bass guitar frequencies are ~40-200Hz, (not counting harmonics). It is only at the 4th fret of its highest string that a bass guitar exceeds 120Hz, (commonly referred to as the point where people can begin to "localize" sounds). This tells me that most bass guitar note are not capable of being "localized".

I'm just wondering how much of an issue it would really be with a high crossover, assuming your sub(s) can recreate the notes as accurately as your speakers. I'm playing around with it. What, if any, issues have y'all detected with a high or very high crossover? (Again, doesn't matter how good your L/R are. Not asking if it's "better". Just wondering what you actually hear relative to localization.)

 

[markw]

the male voice is reputed to go down to 85 hz or so. Paul Robeson may be an outlier but with a high crossover, it's possible that it will be coming mostly from the sub. Now, if the sub is in a funky location, and/or the male voice is abnormally low, it could become disjointed from his upper range if the crossover is set too high..

http://www.axiomaudio.com/blog/audio-oddities-frequency-ranges-of-male-female-and-children’s-voices/

 

[TheWarrior]

In some threads about crossovers, it is mentioned if you set your crossovers too high, you can "localize" bass frequencies... meaning you can begin to tell that the bass is coming from your sub rather than your L/R. This is what I'm wondering about.

I don't recall ever detecting that the bass guitar is coming from the Left or Right. Bass guitar frequencies are ~40-200Hz, (not counting harmonics). It is only at the 4th fret of its highest string that a bass guitar exceeds 120Hz, (commonly referred to as the point where people can begin to "localize" sounds). This tells me that most bass guitar note are not capable of being "localized".

Below the room transition frequency (where resonant bass becomes directional) you shouldn't be able to localize it. Of course this still happens! Much of that has to do with the recording/mastering of whatever the program is, the rest is the room, the equipment, and its placement.

When it comes to selecting an LFE crossover, it just depends on the listener and where the listening is occurring.

Because there is a complete lack of standardization in the recording industry, there can never be a one-size-fits-all solution. So it becomes the responsibility of the listener to constantly adjust subwoofer levels etc. for each different type of program. Music and movies are always played back at very different volumes, and the subwoofer levels in particular really change! One tip I picked up because I listen/watch from one disc player is to use the receiver's inputs to select between music and movies. HDMI for movies, optical for music. Bam! I felt like an idiot for not thinking of that!

 

[herbu]

it becomes the responsibility of the listener to constantly adjust subwoofer levels etc. for each different type of program

That's easy on my Denon receiver. In "stereo" mode, subs are set at +0. In "Dolby D + PLII Cinema" mode, it's +6. But changing the crossover is more involved. Not sure I'd do that back and forth for movies vs music. But I am having fun playing with it.

Mark made a good point, and that was a good link. I realized there are a lot of sounds, voices and instruments, below 120Hz. More than I thought.

 

[TheWarrior]

That's easy on my Denon receiver. In "stereo" mode, subs are set at +0. In "Dolby D + PLII Cinema" mode, it's +6. But changing the crossover is more involved. Not sure I'd do that back and forth for movies vs music. But I am having fun playing with it.

Mark made a good point, and that was a good link. I realized there are a lot of sounds, voices and instruments, below 120Hz. More than I thought.

Did you see my comment about using different receiver inputs for music vs movies? That'll help! Good luck!

 

[BlwnAway]

@herbu, first off, localized bass is a term mostly for HT & multi channel music, and as said earlier, if it comes into play with 2.0 (or 2.2 with your Subs under your mains) listening, your speakers aren't setup for the proper imaging.
In x.1 systems is where it comes into play, and also as stated earlier, it can not only be room and setup dependant, it can vary from person to person, this is why there's no cookie cutter answer.
For "most people" in "most rooms" bass "starts" to become less localizable at around 120hz but the standard for crossover settings is 80hz simply because it covers "most" situations.
But....
One thing to remember about all of this, no matter how many speakers your crossing into your x.1 LFE channel, not having localized bass, isn't only about the crossovers, it's the same as in a 2.0 setup, "placement", just like you need your 2.0 speakers placed properly, so do you need your Sub(s).

 

[sterling shoote]

Seems to me some folks think they'll get "better" results from their surround sound when the low frequency driver is set to reproduce higher frequencies in addition to the designed low frequency reproduction function. Sure, if you can adjust crossover, why not experiment with it. Maybe the bass will become directional maybe not. One thing for sure, there is no singular crossover point or low frequency volume level which will give the listener a satisfying experience with all music and movie media. My system uses a sub, JBL B380, which is ideally controlled with crossover set at 65Hz for use with specific mains, JBL L100t3's. I had this system in use for music before surround sound was on the market. When I play music which has low frequencies, the mains and sub deliver a very satisfying listening experience. When I'm playing music with no low frequencies present, I can't discern the sub being a distraction, it just idles. I can also play movies with my sub as set for music; but, sometimes the effect is more subtle than desired. The remedy is just adjusting the low frequency volume. At any rate, there are no rules here, unless you live in a condo or apartment where any appropriate sub adjustment might anger neighbors.

One sidebar, although I can listen to music and movies at a volume which I perceive as being "right" from my 100 watt per channel amp powering mains and surround speakers, my sub demands a lot more power. I originally hooked it up to an amp producing 300 watts in bridged mode and still experienced clipping. Do you know what clipping sounds like from a 15 inch low frequency driver, it sounds like a sledge hammer banging on a steel pipe. Now, I have a 560 watt amp which so far allows for the highest volume level that I can stand without my ears bleeding.