Can someone explain the bass-management issue to me? (1 Viewer)

[Ted Lee]

hi all - i tried to search, but it's down.
can someone explain this issue or point me to some threads?
i believe it has something to do with the hi-resolution cds and their inability to route lfe to the sub?
what i'm most unclear about is whether the "corrective measures" are done via the cd player or the receiver. or, can it be both? i know outlaw is coming out with the icbm, but i'm thinking outside of that units capacity.
in my head i'm thinking i need to wait until the receiver has this capability, but i assume as long as the cd player can do it then that is just as good?
i don't want to buy a receiver only to find out i need this capability.
just wondering...thanks in advance.

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[PatrickM]

Ted,
Bass management is where you can specify within the receiver what size or bass reproducing capabilities your speakers can handle.
If you have five (or 7) full range speakers you don't need to worry about bass management. By full range I mean reproduce frequencies down to 30Hz or so.
If you have speakers that are limited low frequency you would need bass management. You can set those speakers to small and the bass below the cutoff point (this varies by receiver and some are adjustable) will go to a subwoofer if you have one in your system or the bass will be directed to your large or full range speakers.
People like receivers that have flexible cutoffs or crossover points. My 5800 for example has a fixed 80Hz cutoff and the rumoured upgrade will provide more choices which would be nice.
That's it in a nutshell.
Patrick
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If you live in Vancouver, B.C. or the surrounding areas, take a look at the Local Home Theater Forum Meets section for a Vancouver meet.
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[Ted Lee]

hi patrick -
thanks for the reply.
so the term "bass management" has nothing to do with SACD or DVD Audio?
then, what is the purpose of outlaw's icbm component?
now i'm really confused!

 

[John Kotches]

The issue with SACD and DVD-A players is that some SACD (multi-channel) and most DVD-A players (this is changing with the new round of players introducing at CEDIA) don't have bass management, so could potentially send full range sounds to any of the 5 speakers.
The Outlaw ICBM is designed to work with a multi-channel SACD or DVD-A player that either doesn't have internal bass management, or doesn't include appropriate crossover points for the end users speaker configuration.
Is that what you're looking for?
Regards,
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John Kotches
Contributing Writer
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[Ted Lee]

hi john -
yes...i think this is a little closer to what i was looking for. but i do appreciate patrick's response also!
so, assuming that i'll someday be adopting one or the other format, what should i look for in receiver/player? does the management capability need to be "housed" in one vs. the other?
in my head, i'm thinking it would be more flexible to have the capability in the receiver?
thanks again...
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[Keith Mickunas]

Here's an example of how this is a problem for me. The Grateful Dead are releasing some early albums on DVD-Audio soon. I've heard that they will be putting single instruments in each channel, i.e. Jerry's guitar out of the right speaker and so on. What concerns me is that the bass guitar is going to be in the center channel. When you connect a DVD-Audio (or SACD) player to your receiver, you have to use the 6 RCA jacks (the 5.1 connection) on the player to the receiver. With my receiver (the Yamaha RX-V1) and many others when something comes in the 5.1 connection, it isn't run through the processors, instead it goes straight to the amps. As a result the bass guitar will be going directly to my center channel, which can't handle sounds below 60Hz very well. Now with DD or DTS in my receiver, I tell it the center is small so any bass meant to go through there will be routed to the sub, this is "bass management". But since many DVD-Audio and SACD players have no bass management, and my receiver isn't processing the signal, it could really mess up the sound. If the player had bass management, I would set the center to small and it would route the low sounds to the subwoofer output and all would be well.
So the reason you're seeing this with DVD-Audio and SACD is that now days people buy receivers with DD and DTS capabilities, and they have bass management, but DVD-Audio and SACD are processed by the players, and the manufacturers aren't including bass management in the player.

 

[Ted Lee]

great example keith! thanks for clarifying. so, it sounds like i'll have to look for the bass management capabilities in the cd player? then why am i seeing this feature touted in some of the new kenwood sovereign receivers? or is this more of the bass management patrick was talking about?
well...in any case i think i've got a better understanding. thanks to all for helping me out!

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[Ashford Little]

Ted, you seem confused about cd players. You needn't be as CD players have the ability to output a digital signal to the receiver/preamp and can therefore use the internal bass management of the receiver/preamp (which they all have).
The issue only affects DVD-Audio or SACD since these are output using analog outputs and the signal is not modified by the reciever/preamp. Since it is analog the receiver cannot digitally send the lower frequencies to an LFE channel thus you have full frequency bandwidth going to all channels. This is usually a problem since most people's center and rear speakers cannot handle much bass information.
Anyway your cd player is fine, it's just a DVD-A or SACD player where you run into trouble. Hope this clears up your confusion.

 

[Keith Mickunas]

Currently DVD-Audio and SACD have to be processed by the player, so they need the bass management. No format (last I heard) had been designated to pass the pure digital info from these players to receivers do to piracy concerns. The Kenwood receivers (like many others) have bass management for DD, DTS, and anything else they're processing (regular stereo signals going through the DSP modes for example), but this would have no affect on anything coming in through the 5.1 connection.
Theoretically, a receiver could take the analog signal coming from the player, process it and send the low signals to the sub as the user specifies. However the downside is the signal would go through all sorts of conversions, analog to digital back to analog, and this messes up the "pure" signal coming from the player. Ideally it would be nice if the player analyzed the sound going to each channel as it pulls it off the disc and passes the low signals to the sub channel before putting it out the analog 5.1 connection to the receiver.

 

[Ted Lee]

Anyway your cd player is fine, it's just a DVD-A or SACD player where you run into trouble. Hope this clears up your confusion.

lol - if i ever get out of my cloud of confusion it will be a great day!

anyway, i do understand that this issue relates only to sacd/dvd-a.
it's pretty clear to me now that the bass-management will need to be done on the player's side, especially since the 5.1 signal is analog. it does seem pretty dense to go from digital, to analog, back to digital just so you can process something on the receiver's end.
this has been a great learning experience...if anyone else has more input i'd be glad to hear it!
thanks much!
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[Brian Perry]

Another problem is that even if the newer players can do internal bass management, you will lose other features of your processor/receiver, such as time alignment.
I am convinced that SACD and DVD-A will be dead in the water unless a digital interface is implemented.
[Edited last by Brian Perry on August 28, 2001 at 05:11 PM]

 

[Philip Hamm]

I am convinced that SACD and DVD-A will be dead in the water unless a digital interface is implemented.

Personally I completely disagree with this opinion, but that's just me.
Technically there's no reason that receivers can't perform bass management purely in the analog domain for their 5.1 ins. It just has not been done that way because it would cost money and nobody thought of this.
Outlaw is releasing a product soon called an ICBM which is an external box that does 5.1 bass management purely analog. They developed the ICBM with Dolby Labs. I am probably going to buy one since I have the need.
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Philip Hamm
AIM: PhilBiker

 

[John Kotches]

All,
As an FYI....
There are several DVD-A players coming out which will have Bass Management now -- the announcements so far are from:
Kenwood, EAD, Denon.
There are others I'm probably missing.
Whether they also have time alignment capability is another story, and that remains to be seen.
Regards,
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John Kotches
Contributing Writer
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[Ted Lee]

Whether they also have time alignment capability is another story, and that remains to be seen

that's a term i've never heard before...what's that?

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[Jay_E]

Philip Hamm said:

7.1 channel bass management including the 7.1 direct input for DVD-A and SACD

He also said it is done in the analog domain. These new receivers seem to have every new format and feature with the exception of THX certification. Check out this post for full spec of the R-963 http://www.hometheaterforum.com/uub/.../042814.html#2
Jay

 

[PatrickM]

Ted,
Time alignment is the ability to adjust the timing of the audio signal relative to the other speakers so that the audio signal arrives at you seating location at the right time. You need to be able to adjust this because everyone's speaker placement relative to the listening position is different.
Ultimately if you could place all the speakers equidistant from your seating position you wouldn't have to worry about this but most of the time its not practical.
Patrick
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If you live in Vancouver, B.C. or the surrounding areas, take a look at the Local Home Theater Forum Meets section for a Vancouver meet.
My DVD Collection

 

[Ted Lee]

oh...i'm just thinking too hard. i thought this was some new, super-cool feature. thanks!
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