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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 05-20-2010 9:23 AM by Razlaw. 54 replies.
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  • 04-19-2010 9:08 AM

    AST Help & Understanding

    I have read up on the AST & am a little confused. I have a BV40 with a 7.2 underneath, BL5's front & BL9's at the rear/also connected is a BS5. My dealer has installed the AST but as I was not available I have not chatted about it to him, rather I was left a note explaining the positions etc.

    So it seems In AST options  have 'TV' which effectivly turning AST off. Then I have presets 1 -5 which represent various seating positions. I saw in another thread here that AST is not good for 5.1 dolby..I was watching a blu ray film the other night and found it sounded best with the 'TV' option selected.

    I am also quite unsure about the AST presets, to me it just sounds a bit false..ie if I am sitting on the left, it sounds like AST has just whacked the balance across to the right, and vice versa when sitting on the right...I think the  best music sound quality option is just selecting the BL5's for the stereo split...Again not sure how it works in that on the speaker setting if I select 2 for my BL5's or 5 for my surround sound, ...if I go into AST does it work within those settings or does it over ride them?

     I have a fairly central seating position anyway across 3 sofa's so possibly there is not alot to be gained from AST as I am not moving greatly away from the sweetspot.

    Sorry if these are basic questions, but I cannot see on the forum any answers to this 'basic' understanding, I will indeed go into my dealer and enquire about how it works, but I always feel better when I am armed with a decent knowledge before I do that.

    Last time I didnt research something first I let the dealer talk me into cabling up the BS5 to my tv's at considerable cost thinking I would have full browsing, only to find out all I can see is the album cover and skip forward or backwards through tracks. When I complain dealer says he will email B&O and enquire..very useful, hence why i try to gleem knowledge nowadays rather than rely on the dealer!

    Thanks

  • 04-19-2010 12:30 PM In reply to

    Re: AST Help & Understanding

    Hi Chris

    Perhaps it would be useful if you had a brief explanation of what AST is and what it does for you.  Lets start with the problem first, a DSS set-up has a 'perfect' set-up which is often compromised for convenience, pure aesthetics or to simply to please your partner so you can have the loudspeakers you want :-)

    The perfect setup would have you sat directly infront of your screen with the front left/right loudspeakers at an angle of 30 degrees from perpendicular.  Your surround (often mistakingly called 'rear') loudspeakers should be at an angle of 110 degrees from perpendicular and all loudspeakers should be at an equal distance from your head.

    This is where the problem lies, most people cannot put their loudspeakers in the perfect position so you often have surround loudspeakers too close to your head or one loudspeaker too close to the TV etc.  As a result the spatial qualities of the recordings just fail.  You will hear the sound from one loudspeaker more than you will another.  You can correct for this to some extent using the speaker distance and level settings with the television.  However, this only corrects and optomises for one listening position, this is where AST comes in.

    AST creates a sweet 'area' rather than the traditional sweet 'spot'.  This means you can have the impression of the perfect surround sound set-up, even though your loudspeakers are placed in a less than perfect position.  So, I can put the loudspeakers where Mrs Bell tells me they have to go but make it sound like it should so Mr Bell is happy too....everyone wins and we all stay married :-)

    Of course, if you can setup the prefect listening position (or close to it) then you shouldn't use AST, afterall AST is using very advanced algorithms to immitate the perfect setup.  If you already have the perfect set-up then lets not try an immitate it.

    Another advantage is that you can have more than one listening position.  Perhaps you have a favourite chair when you watch the sport but Mrs Bell has a different seat when she wastches the movies.  No problem, I have more than one pre-set position and just ask the TV to optomise each one accordingly.  Alternatively you might have a preferred position for watching TV and a completely different position for listening to music.  No problem, each can be set-up to give you the perfect listening position.

    So in summary, you can choose which loudspeakers you would like and where you want to put them, we will make it sound like it should

    Hope that helps

    Doug

     

    PS  Acoustic lenses correct for timberal faults, not spatial errors. i.e you hear everything in the performance because of the lenses, you heard it from the correct position because of AST.

  • 04-19-2010 1:40 PM In reply to

    Re: AST Help & Understanding

    Thanks for the excellent explanation. Any comments on AST where the speakers are basically in the correct locations but the possibility exists to add two more as rears that would not be ideally placed? I.E. 5.1 positions are almost ideal, but positions for extra speakers to make 6.1 or 7.1 are not ideal?

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-20-2010 9:58 AM In reply to

    Re: AST Help & Understanding

    Thanks Doug, that explains quite nicely how its working etc, however I am still not quite understanding the way it works with the existing system.

    If I select AST say preset 1 whilst watching a film, does it know and switch to a 5.1 surround, or does AST work only really on stereo fields?...If i select speaker 2 on the TV ( for front left & right speakers only ) then goto AST does it selct AST to work within the chosen speaker assisgnment or does it overide it in some way?

    I suppose i am looking for clarification as to how AST integrates with the standard speaker 1 -4 system, as it worked pre AST the speaker function worked as follows..1 being TV 7.2 speaker only, 2 being stereo front left & right only,3 being 7.2 + front left & right, 4 being stereo l & r fronts & l & r rears together, 5 being surround sound.

    So now what happens when I say want to listen to music in speaker mode 2 with AST?...do the presets in AST alter to move the sweet 'area' in this mode only or does AST just totally override the speaker options & use all the speakers in a full surround mode all the time?

    I have to say so far I have found that its best just to use the front BL5's when listening to music, and then just use the standard speaker 5 ( default ) option with AST set to TV when watching a 5.1 broadcast....I am struggling to see what AST is doing for me, in that to my ears its better switched OFF...possbily as you say due to me having a fairly central listening position anyway. I dont understand though why AST set to TV ( ie off ) should be beter than AST set to preset 1 which is supposed to represent the central listening position, shouldnt these two positions be excactly the same??

  • 04-20-2010 1:27 PM In reply to

    Re: AST Help & Understanding

    Hi Chris

    When AST is switched on there is no longer a speaker 1,2,3 etc option, indeed Front left/right etc no longer exist.  There are simply loudspeakers that play sound and depending on their position they might play a bit of centre channel, a bit of front channel or even a bit of surround channel as well to give the total illusion of a correct surround sound placement.

    Imagine you were in the middle of a field with a perfect DSS setup and no obstructions.  If you play a sound through, say, front left you will be able to close your eyes and tell me where the sound is coming from.  Now leave those speakers where they are and put a room around you that has lots of randomly placed open windows.  If you play the same loudspeaker you will hear the sound travelling in through the windows at various volumes etc.  You will still be able to locate the loudspeaker correctly.  Final step would be to replace those windows with a loudspeaker and play through them the sound that would have come in through the window.  Each one will play a different part and will play a bit of this and bit of that to give the overall total phantom 'perfect' DSS setup

    It seems to me like you have a pretty good set-up already and don't really need AST.  If you cannot hear a big difference then either you already have a good setup and don't need it or it has been setup incorrectly, I suspect your setup is good enough already not to need it.

    It also seems like you only have one listening position for all sources so again, there is limited benefit for you.  Try leaving the TV in speaker 5 and moving to one extreme side of the soundstage - you will hear the sound crashing into the loudspeaker closest to you.  This is just to demonstrate how AST could help you, not to say you need it.

     

    Doug

     

  • 04-20-2010 1:30 PM In reply to

    Re: AST Help & Understanding

    Hi Razlaw

    AST works better the worst placed the loudspeaker are.  In other words, the nearer your setup is to perfect, the less you need AST.

    I guess it depends on how badly placed your rear loudspeakers are.  Perhaps you could ask you dealer to upgrade the software and try different configurations for you.  I would say though that the upgrade and set-up isn't a simple task, it will require laser measures etc to ensure the correct readings are placed in the TV so it may take a while to do.


    Doug

  • 04-20-2010 2:08 PM In reply to

    Re: AST Help & Understanding

    Thanks. We have a Bevision 7-55 ordered and I already have the extra speakers so I will probably go ahead and try it out.

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-21-2010 4:00 AM In reply to

    Re: AST Help & Understanding

    Hi,

    Just thought that I'd drop into this Forum to help out - since I'm the guy in Struer behind AST... Doug's answers are perfect - he said what I would have said if I had gotten there first...

    I've just a couple of minor things to add...

    For info on speaker placement for 7.1, a good place to look (and get more confused) is this page on the DTS website. As you'll see, at least in the case of DTS, there are multiple options. Some of these are compatible with the "official" recommendation for 5.1 (Google search for "ITU-R BS.775.1" for the full version of Doug's description above...) and some are not.

    Regarding the "philosophy" behind AST. The idea is that we're using the loudspeakers you have, in the places you've put them to simulate a "perfect" virtual loudspeaker configuration outside your room. However, as Doug mentioned, if your configuration is already pretty good, then it doesn't make sense to turn on AST - it will actually make things worse. HOWEVER, if you do have a "perfect" setup and you use it incorrectly (i.e. turn in your chair to face the side: now you've got 2 surround speakers on one side and 3 front speakers on your other side) then maybe AST will help you out (more than simply routing the left channel front channel to what would normally be your left surround loudspeaker and your right channel to your left front loudspeaker). This is exaclty why we made it is possible to have some presets with AST disabled, and some with it enabled. My standard line is to tell people "try it out - if it sounds worse, then turn it off". As Doug said, the worse your loudspeaker placement, the more it will help you.

    I'll keep an eye on this forum, just in case there are more issues that I can help out with.

    Cheers

    geoff martin, Ph.D.

    Tonmeister & Specialist in Sound Design, Bang & Olufsen

     

    Filed under:
  • 04-21-2010 4:21 AM In reply to

    Re: AST Help & Understanding

    Thanks Doug & Geoff, You have totally explained it to me. Was messing around last night with it, and yep I have found that as I am fairly central with BL9's behind left & right & BL5's up front left & right that indeed I find my sound quality better without AST on.

    For music, I simply use the stereo BL5's and if I want an extra 'kick' to surround me I add the BL9's to the mix. For films then the 5.1 setup works the best.

    AST works ok if I move to the extreme left or right of the room ( living room is 40 foot long,20 foot wide ), if I then select one of the presets set up for those positions then you can tell AST has moved the sound about a bit to compensate. However really for me it hasnt been money well spent as I have 3 sofa's in a C shape central in the room which is the only sitting positions one would use when watching or listening to music in that room. I have also found that without AST the sounds are much more seperate,defined and dynamic, with AST on it seems to blur the sound a little, sort of blends it all in, almost reminds me of listening to a .wav lossless music file compared to a compressed mp3 file..yes it smooths highs & lows out etc, but it looses some of the clear edge....maybe that is because the BL5's & 9's are such good speakers & as I said I am central, so they work best being allowed to do their thing with no intereference!

    Anyway cool title Geoff, the Tonmeister...liking that alot!...thanks again to you & Doug for taking the time, I feel I have it all sussed out now, cheers

  • 04-21-2010 4:29 AM In reply to

    Re: AST Help & Understanding

    Hi Chris,

    One thing I have noticed in more rectangular setups (you say that your living room is 40x20...) is that it might improve things in AST to "cheat" a little on your listening position. If the preset's listening position is too close to one (or more) speakers, then you might find that things misbehave a little - especially with surround material (typical symptoms are a "darker" sound color, or one channel sticking out in one speaker...).

    A simple solution is to lie to your Beosystem3. When you make the AST preset, place the Listening Position more in the middle of the room than the chair that you're actually sitting in. This might clean things up a little.

    Cheers

    -geoff

     

  • 04-21-2010 4:49 AM In reply to

    Re: AST Help & Understanding

    Oops.... Sorry Chris - I forgot one more thing... remember that AST is, indeed, a simulation of the real thing. You gain flexibility in loudspeaker placement, listening position placement and the direction you're facing. However, the "price" of this is precision. If you're looking for precise localisation, distance and depth in your stereo/multichannel image, then you probably won't get it with AST on. Source location will become "fuzzy" or like a "cloud" rather than a point source. On the other hand, you'll be able to move around the room and hear the same cloud, whereas, with regular stereo, a 10 cm move away from the sweet spot will result in all images dumping into the closest speaker...

    Cheers

    -geoff

  • 04-21-2010 5:18 AM In reply to

    Re: AST Help & Understanding

    Superbly put Geoff...'cloud' as opposed to 'point source' sums up exactly how the AST seems to work for me..Im really pleased it all makes sense now I have the understanding...taken on board all your advice/points, thanks again

  • 04-21-2010 5:47 AM In reply to

    Re: AST Help & Understanding

    Just wanted to say that it's fantastic to have direct input from the people behind the design and products on the forum! Thanks for joining and posting, Geoff Smile

    -mika

  • 04-21-2010 6:00 AM In reply to

    Re: AST Help & Understanding

    No problem! I can't guarantee that I'll be fast to reply all the time, but I'm happy to help out if I can. I think that a new concept like AST is a little difficult to wrap one's head around when it's in its early stages, so I'll certainly pay more attention to this forum than the discussions on older, more well-known products.

    cheers

    -geoff

  • 04-21-2010 7:58 AM In reply to

    Re: AST Help & Understanding

    Thank you very much for stopping by and giving your expert input on it!

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-23-2010 7:19 PM In reply to

    Re: AST Help & Understanding

    Geoff,

    I have a 7.1 B&O speaker setup with my BeoSystem 3. All 7 speakers are rarely used. Moreover, there is a difference in sources as to which 5.1 speakers are used: with blu-ray (via PS3) 5.1 uses the side surrounds but not the rear surrounds, but TV and DVD use the rear surround speakers but not the side surround speakers for 5.1. Will AST help with a 7.1 speaker setup? 

    BTW, does the new BeoSystem 3 update correctly show that 7.1 sound is being passed through when selecting "sound system" on the BS3 menu? Currently, When I check the "sound system" it shows the input as PCM 7.1 but the output as 5.1 - even when all 7.1 speakers are outputting sound.

  • 04-24-2010 8:27 AM In reply to

    Re: AST Help & Understanding

    beojeff:

    I have a 7.1 B&O speaker setup with my BeoSystem 3. All 7 speakers are rarely used. Moreover, there is a difference in sources as to which 5.1 speakers are used: with blu-ray (via PS3) 5.1 uses the side surrounds but not the rear surrounds, but TV and DVD use the rear surround speakers but not the side surround speakers for 5.1. Will AST help with a 7.1 speaker setup? 

    There are two issues here...

    - Regarding which speakers are playing for 5.1 from different sources. How do you have your speakers labelled in the setup menu? (In your posting you say "side surround" and "rear surround" but the BS3 will say "surround" and "back" - which is which for you? Once I get that info, I can check this out with my BeoSystem3 and a PS3.)

    - If you have AST, you will get sound from all speakers (that you've turned on in the Preset you're using) all the time, regardless of the number of input channels. However, if your 7.1 speaker configuration is reasonably good (meaning that your speakers are well-placed and fairly symmetrical in the room) then AST might not help you - at least for the specific case of sitting in your sweet spot and watching television. If you're far away from the sweet spot, then AST might help.

     

    beojeff:

     

    BTW, does the new BeoSystem 3 update correctly show that 7.1 sound is being passed through when selecting "sound system" on the BS3 menu? Currently, When I check the "sound system" it shows the input as PCM 7.1 but the output as 5.1 - even when all 7.1 speakers are outputting sound.

     

    I'll check on this and get back to you.

    Cheers

    -geoff

    Filed under:
  • 04-24-2010 8:56 AM In reply to

    Re: AST Help & Understanding

    Thanks for the response, Geoff. I have the speakers correctly labeled as "surround" and "back." (I just used the terms "side surround" and "rear surround" to be more descriptive.) It seems odd that the BS3 uses the (side) surround speakers and not the rear speakers for 5.1 blu-ray, but the BS3 uses the rear speakers and not the (side) surround speakers for 5.1 with all other sources (tv, dvd, AppleTV). I'm guessing that the reason has something to do with the PCM through the blu-ray player reserving the rear speakers for 7.1.

  • 04-24-2010 9:27 AM In reply to

    Re: AST Help & Understanding

    Geoff, could I ask a few questions also about speaker placement and AST?  Our current system is a Beovision 7 MKIII with a Beolab 7-4. Front speakers are Beolab 9s and rear speakers are Beolab 1s. We have a Beovision 7-55 ordered which will be replacing the Beovision 7-40 soon. Now for the questions:

    1. The Beolab 1s are placed in the back corners of the room/sitting area. Just behind and to the sides of the sitting area. In the setup menu they are identified as as left and right surrounds. Is this the correct setting for a 5.1?  My understanding is that it is but the next question will explain why I ask.

    2. We have a pair of Beolab 6000s I am thinking of adding to create either 6.1 or 7.1. My understanding is that these would be placed approximately in the center rear behind the sitting area and either both identified as center rear for 6.1 or identified as left and right rear for 7.1. Is this correct?  I ask because a member of this forum told me that the 6000s should be added to the sides between the front 9s and rear 1s which would put them in front of the seating position. As I look at all of the options in the setup menu and diagrams in the Beovision owner's manual it appears to me that our current 5.1 is correct and additional speakers would go behind the the current sitting area.

    3. Assuming our 5.1 setup has the speakers in almost ideal locations, if the 6000s were added for 6.1 or 7.1 they would not be in ideal positions. Our room is about 15 feet by 17 feet. Should I expect the sound from a nearly ideal 5.1 without AST to be better than 7.1 using AST to adjust for the poor positions of the extra two speakers?  Or would a 7.1 with the two rears in less than ideal locations but with AST sound better than the non AST 5.1?

     

    Thanks!

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-24-2010 3:03 PM In reply to

    Re: AST Help & Understanding

    Razlaw,

    I think our issues are very much related. When you add the extra two speakers to get 7.1, I suspect that you will find that the PCM from your blu-ray will use the (side) surround speakers during 5.1 but that all other sources will use the rear speakers and not the (side) surrounds. This can make quite a difference since your Beolab 1s and your Beolab 6000s are worlds apart in terms of sound.

    Similarly, I have 2 Beolab 8000s as my front speakers, 2 Beolab 8000s as my (side) surrounds, a Beolab 10 as the center, a Beolab 2 for subwoofer, and 2 Beolab 6000s as the rear speakers.

  • 04-24-2010 3:15 PM In reply to

    Re: AST Help & Understanding

    I may try connecting the 6000s now, just temporarily, to our BV7 and see what happens. If I do I will let you know.

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-25-2010 6:22 AM In reply to

    Re: AST Help & Understanding

    beojeff:

    Thanks for the response, Geoff. I have the speakers correctly labeled as "surround" and "back." (I just used the terms "side surround" and "rear surround" to be more descriptive.) It seems odd that the BS3 uses the (side) surround speakers and not the rear speakers for 5.1 blu-ray, but the BS3 uses the rear speakers and not the (side) surround speakers for 5.1 with all other sources (tv, dvd, AppleTV). I'm guessing that the reason has something to do with the PCM through the blu-ray player reserving the rear speakers for 7.1.

    Hi,

    Armed with this info, I'll look into this. One thing with PCM coming in on an HDMI stream is that, in some cases, the receiver (in this case, the BS3) just does what it's told to do by the source (the PlayStation). The source asks the receiver what speakers and channels are available and then it makes some decisions about what signals to send and where to tell the receiver to route them. That is not to say that this is what is going on in your case - but it sometimes adds an additional level of unknown to the problem.

    cheers

    -geoff

     

    Filed under:
  • 04-25-2010 7:57 AM In reply to

    Re: AST Help & Understanding

    Hi Razlaw,

    Razlaw:

    1. The Beolab 1s are placed in the back corners of the room/sitting area. Just behind and to the sides of the sitting area. In the setup menu they are identified as as left and right surrounds. Is this the correct setting for a 5.1?  My understanding is that it is but the next question will explain why I ask.

    This is correct.

    Razlaw:

    2. We have a pair of Beolab 6000s I am thinking of adding to create either 6.1 or 7.1. My understanding is that these would be placed approximately in the center rear behind the sitting area and either both identified as center rear for 6.1 or identified as left and right rear for 7.1. Is this correct?  I ask because a member of this forum told me that the 6000s should be added to the sides between the front 9s and rear 1s which would put them in front of the seating position. As I look at all of the options in the setup menu and diagrams in the Beovision owner's manual it appears to me that our current 5.1 is correct and additional speakers would go behind the the current sitting area.

    This is correct as well. I would put the BL1's at about +/-110 degrees from front-centre, and the BL6k's at about +/-150 degrees.

    Razlaw:

    3. Assuming our 5.1 setup has the speakers in almost ideal locations, if the 6000s were added for 6.1 or 7.1 they would not be in ideal positions. Our room is about 15 feet by 17 feet. Should I expect the sound from a nearly ideal 5.1 without AST to be better than 7.1 using AST to adjust for the poor positions of the extra two speakers?  Or would a 7.1 with the two rears in less than ideal locations but with AST sound better than the non AST 5.1?

    It sounds to me like your system is well-set-up enough to probably not benefit from AST when you're watching television. However, if you decide to want to face another direction or move off your sweetspot, then an AST preset might give you some benefits.

    Cheers

    -geoff

    Filed under:
  • 04-25-2010 8:18 AM In reply to

    Re: AST Help & Understanding

    Thanks!

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

  • 04-25-2010 9:31 AM In reply to

    Re: AST Help & Understanding

    Beojeff, I connected the two extra Beolab 6000s. All seven speakers work when watching satellite TV or Apple TV. Using our Sony BDP S550 Blu Ray only five work. The added 6000s set as left and right rear are silent. I want to try listening to 3:10 to Yuma as it has a 7.1 PCM track but we loaned our copy to a friend. Also, even when all speakers are active, the TV still says 5.1.

    Beovision 7-55 with Beolab 7-4, 9s and 4000s

    Beovision 10-40 with Beolab 1s and 6000s

    Beosound 1, 5, 2000, and 3000

    Beotime, Beotalk, Beocoms

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