Bass management question

[Vaughan Odendaa]

Hello,

I'm trying to understand something. Speakers set to small (subwoofer on), sends bandwidth limited signals to each main speaker and redirects the bass in those channels to a subwoofer.

I know that some mixing engineers mix deep bass in the main channels. But if I tell bass management to copy the bass from those channels and sum it up (in conjunction with the LFE), surely I should be hearing all the bass in that soundtrack ?

But here's the thing. I did a quick test this afternoon. I put on Pearl Harbour. In the menu, there is some music with loud drums playing. Setting the bass to small, the drums don't sound powerful at all so naturally, I assumed that there wasn't much bass present, or, perhaps the drums aren't supposed to sound big.

However, I tried setting the speakers to large (subwoofer on) and the drums sounded way more powerful. It sounded far more realistic.

Keep in mind that I used an 80 hz crossover before. The speakers I was using were Polk RTI 8 floor standing speakers with Polk subwoofer. I was under the assumption that high passing the main speakers would redirect all bass present to the subwoofer in addition to the LFE track.

So in theory I should be hearing all the bass present right ?

Perhaps I am hearing sound wave reinforcement (having both mains playing full range signals in unison with subwoofer) which might explain the far more powerful sound.

Thoughts ?

--Sincerely,

 

[Adam]

I have some thoughts, and questions.

When you set the main speakers to large, did you have the system set up to send bass below 80Hz to both the speakers and the sub, or did you have it set up to only output the LFE to the sub? If you had bass going to both the mains and the sub, then it makes sense that those frequencies would get louder because they are being played at full volume through both the mains and the sub. If, however, you only had bass going to the mains (with the exception of the LFE track), then I have a couple of thoughts.

First, the bass in the frequencies that mattered in that scenario (the ones that made you feel that it was more powerful and realistic) may be played better through your main speakers. It could be that the speakers are just better than the sub at it, or (more likely to me) it's a function of your room acoustics. Perhaps the sub is in a location that causes certain frequencies to be partially cancelled out, at least in your listening position. When playing my sub in my room, there's a big dip in volume around 100Hz in my listening position...but five feet away in another chair, that dip isn't there but rather occurs around 90Hz.

Just some thoughts.

 

[Warpdrv]

I have played with different X-Overs as well... depends on the content, but I have gone back and forth with 60hz and 80hz and then ran some Freq. response tests... in my particular room I get a null introduced right around 60 hz with the lower x-over point... at a x-over at 80hz, the null is gone...

My point is that what might be happening with your setup may be caused by the acoustical properties of your room.... You should do some room sweeps and see what is going on if you haven't already.

I agree with Adam... very good advice... try different locations with your sub, or room treatments, Phasing could also be a factor here.. Did you experiment with setting your phase and the SPL Meter... ?
More then likely as Adam said... its a product of your environment.

 

[Buckle-meister]

...if I tell bass management to copy the bass...

You're not copying bass, you're simply telling the receiver "my speakers aren't capable of playing frequencies below [insert number here]Hz so anything below that send to my sub would you?" The total amount of bass remains constant, all you've done is sent some here and the rest there.

When you set the main speakers to large, did you have the system set up to send bass below 80Hz to both the speakers and the sub, or did you have it set up to only output the LFE to the sub?

I think you may be confused re LFE? You set Bass Out either to Both (i.e. speakers with sub) or Sub (i.e. subwoofer alone); LFE is the discrete Low Frequency Effects channel on DVDs etc and is directed to Both or Sub just the same as all 'regular' bass in a soundtrack.

 

[Adam]

I think you may be confused re LFE? You set Bass Out either to Both (i.e. speakers with sub) or Sub (i.e. subwoofer alone); LFE is the discrete Low Frequency Effects channel on DVDs etc and is directed to Both or Sub just the same as all 'regular' bass in a soundtrack.

What kind of feature-limited receiver are you using? Probably some junky Yamaha like an RX-Z9.

Yeah, I think that you got me. A little tired this morning, I suppose...or at least that's what I'm going to claim. I have some recollection that my older Yamaha let me send bass to the sub (for all "small" speakers and the LFE track) and, if I wanted, have bass for the front mains (and only the front mains) be sent to both the mains and the sub. I think that I might have to go look at the owner's manual...

 

[Buckle-meister]

What kind of feature-limited receiver are you using? Probably some junky Yamaha...

W A R

Oh, outdated at the very least.

 

[Adam]

I have some recollection that my older Yamaha let me send bass to the sub (for all "small" speakers and the LFE track) and, if I wanted, have bass for the front mains (and only the front mains) be sent to both the mains and the sub. I think that I might have to go look at the owner's manual...

Aha! My memory has not yet failed me. I just read the owner's manual, and I was correct. When "LFE/BASS OUT" on my Yamaha RX-V992 is set to "BOTH" then LFE and other low bass signals from "small" speakers are sent to the subwoofer and low bass signals from the mains are sent to both the mains and the sub. The mains would only play the LFE track and bass from "small" speakers if no sub was connected and the "LFE/BASS OUT" was set to "MAIN."

 

[Vaughan Odendaa]

First of all, thank you for all the replies. Adam, I set up the bass management so that the sub will handle the LFE and set the speakers to small. I was using an Onkyo receiver and turned "double bass" off.

I used sound pressure meter and calibrated the speakers to reference level in addition to the subwoofer level. I tested phase and things seemed perfect at 0 degrees.

--Regards,

 

[Vaughan Odendaa]

The room is a shop which is massive. For the record, using the word "copy" instead of "sum" would have been more accurate.

Sloppy I know.

--Regards,

 

[Buckle-meister]

When "LFE/BASS OUT" on my Yamaha RX-V992 is set to "BOTH" then LFE and other low bass signals from "small" speakers are sent to the subwoofer and low bass signals from the mains are sent to both the mains and the sub. The mains would only play the LFE track and bass from "small" speakers if no sub was connected and the "LFE/BASS OUT" was set to "MAIN."

Well o b v i o u s l y A d a m.

 

[Shashi Kumar]

Wow!!!!!!!!!

Marantz only allows you this choice for stereo. for 5.1 the LFE and bass of all "smalls" are from the sub.