Hi all, I am interested in solving a most peculiar problems with my lab 5s. I emigrated to Melbourne Australia from LOndon and brought my BV5, Lab 5s, Lab 3s and Bs9000 with me. In London My Lab 5s were in a 18 foot by 13.5 foot room resting on wooden floors with underlay and laid on a Concrete base / foundation. My lab5s sounded great with really tight and deep base. In Melbourne our house is built on concrete footings spaced under our solid wood floors i.e there is a metre high gap under our floors (all the air-conditioning and heating duct work is under here). No matter how much I try to calibrate the lab5s I do not get the same RICH deep but tight bass output.

Does anyone have any  ideas to experiment towards a solutions ?. Its almost as though the speakers start to compensate due to the gap beneath the floor and somehow lower the bass output !

 I remember quite a neat trick touted by many of the pro trade installers for bookshelf speakers. Either gel foot rests to damp out vibration or just three or four blobs of blue tack did the trick. I wonder if something similar would do for Lab 5s. 

Not sure Blu-Tac will have much effect on BL5s!

I would suggest damping the room a bit when you do the test sequence. More furniture, maybe rugs if you don't have carpet down and some more bodies in the room. Then remove said bodies etc and see what it sounds like. Probably take some trial and error to get them as you wish. Try moving the speakers away from the walls a bit more as well.  

You'll find great variations in where the bass impacts depending upon placement and listening position.

B&O's claim that these speakers will adapt perfectly to any room and can be positioned anywhere is a bit of a stretch. I get great differences if I place them in different places. 

Here's an image showing how energy dissipates in a room 5.3x3.6m from a woofer (here placed in the middle of the room, but don't bother with that) - it just shows you how you'll have peaks and valleys with more or less bass in different positions in the room (height, width, length coordinates).

 Here's a quick snapshot from my listening room. I've tried the speakers in the corners, at a position just in front of the edges of the cabinet, and where they are now (and a lot of places in between.)
For accurate listening, with a natural bass rendition, where they are now is best. The calibration buttons are 1.77m from the back wall and 1.08m from the side walls. When I had them about 80cm farther back, there was imprecise bass in my listening position - but lots of bass about 60 cm in front of it. My head, when listening now, is 2.9m from the central column of each speaker.

So - first set them up where you'd like to have them, but have a chair and move that about until you find a good bass. See if that's where you'd like to have your listening position. If not, then you're probably going to have to move the speakers about and have the listening position fixed.

Yes - your room could be soft, or the cavity underneath could be swallowing the bass. You could always set up your speakers in a larger room, and then move them into the one you're intending them for, in case you're very bass hungry. But I've found them to be able to accommodate well to a variety of room configurations, if natural bass rendition is the goal. And in spite of the room calibration evening things out somewhat compared to the illustration above, you will still have to contend with and accommodate how the sound waves are propagating in the room.
 

B&O's claim that these speakers will adapt perfectly to any room and can be positioned anywhere.

Forget it!

In some cases the callibration doesn't goes well,to much bass.

I'm wondering if b&o will come with better callibration software for difficult houses.

I can't understand why they didn't make a manual fine tune button for the low frequencie at the back side of the loudspeaker.

I don't know whether they've ever said it will adapt perfectly to any room, but they have said you have great freedom of placement. Which is true if you're not aiming for critical stereo perspective - but if you are, then you should follow traditional rules of placement. And there  will always be room shapes/materials that any kind of bass-calibration on this level couldn't do anything with.

I remember you've had some challenges with your speakers, which you felt gave too much bass. That's a problem I've never encountered, though I have tried them in a variety of different rooms. 

I'm in the process of installing an ARC software solution in my listening room, which will control the entire frequency range of all audio output to my speakers when listening in stereo.

http://www.ikmultimedia.com/arc/

One would need this program, plus a DAW (digital audio workstation) program. You then measure your room and have the program recalibrate the output to fit a target frequency distribution. Sounds complicated and isn't, once set up the processing will be handled by my Mac mini. B&O should offer it as built-in, in their BeoCenter 2 Audio and the coming BeoSound 5, to show they are serious about perfect sound. (There are various surround sound receivers that have such Audyssey room calibration incorporated.)

I'd advice both the thread starter and Koenig to look into those possibilities, you end up with fantastic sound even in problem rooms.

http://www.audyssey.com/ 

I don't understand it,

How do you connect this to the beolab and beosound?

The signal that comes out of your BeoSound has to be passed through the software, before being sent on to the speakers.

As I'm not using a BeoSound, but playing from a harddisk, I can do the processing in the computer before sending the processed signal to the speakers.

But in your case I would consider using this:

http://audyssey.com/soundequalizer/index.html

There's one problem. Depending upon the kind of player you have, you would need to bypass the signal information from the PL cables to the Audyssey, while sending the control information on to the BeoLab speakers. In that way, you keep control of the speakers (Volume, ON/OFF, etc.) through the BeoSound, while ensuring the sound is processed before it's sent to the speakers. The processed analog out signal from the Audyssey can just be remarried to the PL cable after processing. (Hope this is not too confusing - just imagine that you have to branch the signal information out from the main PL cable, through the Audyssey, and then back to the PL cable.)

The issue will be the meter or so gap between the speakers. Instead of the bass firing down onto a solid floor which will help reduce unnecessary vibrations/reinforce bass reproduction, the sound will be traveling into what is essentially a giant box (boxes + bass = disaster) - kinda like placing a subwoofer on top of a large wooden box (it's going to sound sloppy, slow and 'empty).

Short of reinforcing the floor with concrete blocks or filling in the gap with concrete or generally making the floor more rigid, you won't be able to do too much.

That doesn't mean the issue doesn't lie somewhere else though. High ceilings and a lack of soft furnishings will really make things worse.

Alex:

The issue will be the meter or so gap between the speakers.

You mean underneath, right? I understood it as being a space underneath the entire floor, and not just where the speakers are.

It can be a problem, but doesn't have to be a total spoiler - you can even place the speakers on heavy stone slabs - often done with other speaker types in order to prevent soft floors from going active when the woofers work. Also make the slabs larger than the footprint of the woofers, to have the energy move into the room, and not have a lot of it dissipate through the floor. (I doubt that the floor itself is very thin, though, in spite of the service "cavern").

soundproof:

Alex:

The issue will be the meter or so gap between the speakers.

You mean underneath, right? I understood it as being a space underneath the entire floor, and not just where the speakers are.

It can be a problem, but doesn't have to be a total spoiler - you can even place the speakers on heavy stone slabs - often done with other speaker types in order to prevent soft floors from going active when the woofers work. Also make the slabs larger than the footprint of the woofers, to have the energy move into the room, and not have a lot of it dissipate through the floor. (I doubt that the floor itself is very thin, though, in spite of the service "cavern").

Sorry - that is what I meant.

If slabs are the way forwards, visually it would work best if they were circular and in line with the tapering of the speakers (maybe some clever mathematician can work this out?).

Hi Peter,

It's always difficult to get across a precise meaning with words, I think I confused you - what people do is place slabs of stone or other materials on top of the floor, under the speakers. This is to provide a solid base for the speakers "to kick off from" if the floor is soft (in old buildings it may even have begun sagging and starts resonating to the woofer signal.)

With your cavity underneath, such a slab might do the trick. They're the same stone bases one sometimes place under a grand piano.

Check the bottom of this link to get the general idea:

http://www.hifi-notes.com/sonusfaber1-en.htm 

 Here is a link on the topic:

http://www.audiokarma.org/forums/showthread.php?s=5f9f92d097b13a7046e7a74e99147172&t=150286

soundproof:

Alex:

The issue will be the meter or so gap between the speakers.

You mean underneath, right? I understood it as being a space underneath the entire floor, and not just where the speakers are.

It can be a problem, but doesn't have to be a total spoiler - you can even place the speakers on heavy stone slabs - often done with other speaker types in order to prevent soft floors from going active when the woofers work. Also make the slabs larger than the footprint of the woofers, to have the energy move into the room, and not have a lot of it dissipate through the floor. (I doubt that the floor itself is very thin, though, in spite of the service "cavern").

when you put a stone slab under your speaker,the beolab5 will then produce more bass because the woofer is higher above the ground.

I think that ain't gonna work.

Well, in this instance he wants a stronger and sharper bass, as it's now being swallowed by the cavity underneath (theory) - and that's when you'd use such a slab. Particularly with the downward firing subwoofer, imagine part of the soundwave today going into the room, while some goes through the floor and is then reflected up again -- that might muddle up the bass to what he's hearing now.

These slabs might focus the bass propagation. I've heard it work really well in some instances.

I would still recommend moving the speakers around first, as they're now in the corners. 

Velodyne subwoofers also have a room correction system,but they use a freestanding microphone,you put the microphone were you are listing and then callibrate.

I think that's a better way for callibration

Is it not possible to develop special "room" callibration software for those people who at problems with there beolab5 bass output?

koning:

soundproof:

Alex:

The issue will be the meter or so gap between the speakers.

You mean underneath, right? I understood it as being a space underneath the entire floor, and not just where the speakers are.

It can be a problem, but doesn't have to be a total spoiler - you can even place the speakers on heavy stone slabs - often done with other speaker types in order to prevent soft floors from going active when the woofers work. Also make the slabs larger than the footprint of the woofers, to have the energy move into the room, and not have a lot of it dissipate through the floor. (I doubt that the floor itself is very thin, though, in spite of the service "cavern").

when you put a stone slab under your speaker,the beolab5 will then produce more bass because the woofer is higher above the ground.

I think that ain't gonna work.

No the opposite will happen. At the moment, the wooden floor isn't substantial enough to act as a proper floor when it comes to very low frequencies (and the BeoLab 5s go low, very very very low!) and as a result, the speakers are effectively floating above the gap between the wooden floor and the true floor below. Adding a concrete slab underneath the speakers (assuming the floor can handle a large weight) will almost act as a second floor...

koning:

Is it not possible to develop special "room" callibration software for those people who at problems with there beolab5 bass output?

 

Look above. Audyssey, or the ARC solution. 

Again, all, thanks for the responses. Last night I thought I'd try the easy bit first. So I moved the lab5s that were in the two corners of the room and about 12 inches from the back wall, a further 1 and a half foot away from the back and side walls, re calibrated and guess what, the base seemed a lot better. (I played a particular track with very low bass frequencies on a before and after scenario).

 Now, chaps, as most of you know, I had to weather the initial shock from my wife when I told her I needed GBP 30,000 pounds for my system and then when she saw the Lab 5s she actually said what the hell was I thinking getting some INDUSTRIAL MACHINERY into our home !!!. Can you imagine if I now go to her and say the only way to get the very expensive INDUSTRIAL MACHINERYperforming to their optimum I need to place them on concrete slabs ???

 As it stands last Christmas it cost me AUD 55k to get her a new MX5 in "compensation" for "those hideous things"....

Anyway, I can't resist it now. She is away on a long weekend soon, so its off to BUNNINGS (The equivalent of B&Q in the UK, to get some slabs... I can always cover them in the finest black silk .. One question.....how thick do you think these slabs need to be..and can I get away with say 3 - 6 paver slabs on top of each other ?

 I wonder what David Moulton or David Lewis might say ??

Peter

They're hefty, but it's really worth it to move them about a bit, as you're hunting for the best place to have them (that is also realistic as placement!) I got big differences just moving them a foot.

As to thickness of slabs - 15cm+.

And don't get some that ring when you strike them with something, the material they're made of should be quite inert 

15 cm + is going to have to be covered indeed with black silk.... Thanks for your advice. I shall set out this evening to see if I can get 12 paving slabs... I still can't get over the irony...AUD 25,000 worth of speakers now made more effective with a 15 cm slab of concrete worth AUD 25 !!! Still, needs must !!

Peter

There is a place called Peraway Marble (spelling) north of Melbourne. They have very large offcuts available. Could be a little more stylish...

beoaus.