Bass Management Experiment - MOVED

[ronnie 1.8]

EDIT: I just ran across Clint's article Bass Management Basics – Settings Made Simple. It should answer my one speaker size question.

Just read the article, some portions several times. GREAT SUMMARY - thanks, Clint. I'm now going to set all speakers to SMALL and my crossover is already at 60Hz, which I like. I love tweaking!!

 

[AVRat]

ronnie, in your case, with the PSBs and nice Velo sub, the standard 80Hz or maybe 60Hz crossover would be appropriate.

 

[ronnie 1.8]

The review was talking about using the 'source direct' function of the player, if this is selected then the player will not do any bass management so if any BM is required then you'll need a receiver that performs BM on EXT IN(5805 i believe). In your case the 3805 does not do any BM on EXT IN so its advisable not to select the 'source direct' function so the player can perform BM. Or use the Denon Link and let your receiver do the BMcheers

That's very helpful. I didn't realize some AVRs have BM on EXT IN. And you writing my 3805 does not have BM on EXT IN is exactly what I found. Thanks.

 

[ronnie 1.8]

The large and small setting is what tells the receiver/player what speakers get signal below your selected crossover frequency. If you set your mains to large they will get full range signals all the way down to and below 10Hz, if they're set to small then they will only receive bass down to the crossover fq and the rest will be diverted to those set to large and the sub(depending on your sub settings).
So the question is what reproduces the lowest bass the best in your system? In most cases its the sub, so set all your speakers to small otherwise they will be called to reproduce below 10Hz.

My opinion on the matter is, the only time you set your speakers to large is if you don't have a sub.

cheers

So my mains and surrounds extend to 42 Hz and my center to 50 Hz (per PSB), so setting all speakers to SMALL and a crossover of 60 Hz seems like the ticket. And as Clint suggested, I'll re-level my channels. I wonder how much info I was losing on my mains and surrounds by having them set to LARGE. On typical DVDs, is there a lot of info below 42 Hz on the main and surround channels? Or even below 50 Hz on centers? Lots of fun learning new stuff about your system!!! Based on what I've learned, macca350, I agree with your opinion on when to set speakers to large.

 

[MACCA350]

So my mains and surrounds extend to 42 Hz and my center to 50 Hz (per PSB), so setting all speakers to SMALL and a crossover of 60 Hz seems like the ticket. And as Clint suggested, I'll re-level my channels. I wonder how much info I was losing on my mains and surrounds by having them set to LARGE. On typical DVDs, is there a lot of info below 42 Hz on the main and surround channels? Or even below 50 Hz on centers? Lots of fun learning new stuff about your system!!! Based on what I've learned, macca350, I agree with your opinion on when to set speakers to large.

Most movies have actually more bass in the main and surround channels then in the LFE channel, its quite surprising what little bass information is actually in the LFE channel compared to the others.

cheers

 

[ronnie 1.8]

My installer had ALL speakers set to LARGE and crossover at 60 Hz. So that means my sub was receiving (at least from my video DVDs) only info recorded on the LFE channel. Interesting. I'm sure I was losing a lot of info. Now I'll have to watch some of my favorite movies all over again!!

 

[MACCA350]

My installer had ALL speakers set to LARGE and crossover at 60 Hz. So that means my sub was receiving (at least from my video DVDs) only info recorded on the LFE channel. Interesting. I'm sure I was losing a lot of info. Now I'll have to watch some of my favorite movies all over again!!

I did some playing around and made this sonogram of the ID4 scene at the start where the ship passes over the moon. This shows information below 60Hz for all six channels separately and covers about 2min time.

Next I'll do one for WOTW.

cheers

 

[MACCA350]

Now for WOTW lightning scene.

This shows information below 60Hz for all six channels separately and covers all of WOTW chapter 4.

As you can see there is a lot of sub 60Hz information thats not in the LFE channel, especially in the mains, this is why proper bass management is critical.

Next I'll do the famous WOTW chapter 5 emerging scene.

cheers

 

[MACCA350]

Now for WOTW emerging scene.

This shows information below 60Hz for all six channels separately and covers all of WOTW chapter 5.

cheers

 

[ronnie 1.8]

I did some playing around and made this sonogram of the ID4 scene at the start where the ship passes over the moon. This shows information below 60Hz for all six channels separately and covers about 2min time.

Next I'll do one for WOTW.

cheers

This is an amazing graph. I've never seen a graph like this, or anything that depicts this kind of information. Amazing. Macca, what tools did you use to create this graph?

I had no idea so much info below 60 Hz was being sent to ALL non-LFE channels!! Wow, what an eye opener. As all my speakers were set to LARGE, that is information I never heard, that was lost.

Now that my speakers are all set to SMALL, how does the subwoofer respond to the information received as a result of all other 5 channels receiving info below 60 Hz at the same points in time, vs only the LFE channel receiving info below 60 Hz? In other words if the sub is producing a 30 Hz tone at a given point in time, and now that same 30 Hz signal from all other 5 channels is getting rerouted to the sub, the sub is now receiving a 30 Hz signal from 6 different channels. Does it now reproduce a sound that is different vs only the LFE channel receiving that 30 Hz signal?

 

[ronnie 1.8]

Now for WOTW lightning scene.

This shows information below 60Hz for all six channels separately and covers all of WOTW chapter 4.

As you can see there is a lot of sub 60Hz information thats not in the LFE channel, especially in the mains, this is why proper bass management is critical.

Next I'll do the famous WOTW chapter 5 emerging scene.

cheers

Right, and what I find most amazing is that the mains are getting the lowest frequences, not the LFE!! I'd like to better understand why the folks respondible for sound (assuming this is from a DVD) of DVD's make these decisions? Do they assume it doesn't matter, as folks have access to bass management? I had no idea this was the case.

 

[ronnie 1.8]

Now for WOTW emerging scene.

This shows information below 60Hz for all six channels separately and covers all of WOTW chapter 5.

cheers

As is the case with another graph, the center is getting frequences below the LFE. I have WOTW, and am looking forward to watching chapter 5 w/ a critical ear to see if I can hear a difference. Of course, now that I know my speakers are set to SMALL, I'll hear a difference, whether I do or not!

 

[MACCA350]

This is an amazing graph. I've never seen a graph like this, or anything that depicts this kind of information. Amazing. Macca, what tools did you use to create this graph?

I used DVD Audio Extractor (because it allows you to extract the separate channels) and Sound Forge 8.0

I had no idea so much info below 60 Hz was being sent to ALL non-LFE channels!! Wow, what an eye opener. As all my speakers were set to LARGE, that is information I never heard, that was lost.

Now that my speakers are all set to SMALL, how does the subwoofer respond to the information received as a result of all other 5 channels receiving info below 60 Hz at the same points in time, vs only the LFE channel receiving info below 60 Hz? In other words if the sub is producing a 30 Hz tone at a given point in time, and now that same 30 Hz signal from all other 5 channels is getting rerouted to the sub, the sub is now receiving a 30 Hz signal from 6 different channels. Does it now reproduce a sound that is different vs only the LFE channel receiving that 30 Hz signal?

I'm not sure exactly how the information is processed(someone else can jump in on this), but I think it's summed together. Eg, if the 30Hz signal of all channels is identical in every aspect then when they are summed to the LFE channel, there will be no change in the actual signal output except maybe an increase in SPL(only up to the max allowable for that channel(something similar to using the L and R inputs on the back of a sub). At least I think that's what happens

MDS could probably answer this one.

cheers

 

[MDS]

IF they are absolutely identical then summing them will result in an increase in SPL. If you take any old waveform in Sound Forge and copy it to a new window (Ctrl-C, Ctrl-E) then paste-mix it into the original waveform, it will sound the same but the level will increase ~6 dB.

I've never been able to absolutely verify it, but I've read that the mastering engineers duplicate the contents of the LFE into the front channels so that nothing is lost if you have your front speakers set to Large and have no subwoofer. The LFE channel is boosted +10 dB so having a subwoofer play that channel adds to the 'boom' of the soundtrack.

In the case of bass management though where a portion of the signal is redirected to the subwoofer, all of the other channels are combined, low passed according to the xover you've set, and then sent to the subwoofer.

 

[dave1490]

This is an amazing graph. I've never seen a graph like this, or anything that depicts this kind of information. Amazing. Macca, what tools did you use to create this graph?

I had no idea so much info below 60 Hz was being sent to ALL non-LFE channels!! Wow, what an eye opener. As all my speakers were set to LARGE, that is information I never heard, that was lost.

Now that my speakers are all set to SMALL, how does the subwoofer respond to the information received as a result of all other 5 channels receiving info below 60 Hz at the same points in time, vs only the LFE channel receiving info below 60 Hz? In other words if the sub is producing a 30 Hz tone at a given point in time, and now that same 30 Hz signal from all other 5 channels is getting rerouted to the sub, the sub is now receiving a 30 Hz signal from 6 different channels. Does it now reproduce a sound that is different vs only the LFE channel receiving that 30 Hz signal?

this is great software what,s it called.thanks

 

[MACCA350]

this is great software what,s it called.thanks

see post #13

These two sonogram's show sub 60Hz information from WOTW emerging scene chapter 5.
1) LFE channel ONLY

2) The SUM of all channels together(Audio Extractor set to Mono) I'm not sure if this is the same process that receivers use to combine the sub crossover information.

cheers