In the new catalogue there is a really nice looking picture of a red BL11 in a book shelf.

I am currently considering a BL11 to support my BL3 in the dining room and must admit that I get somewhat tempted by this solution. My idea is to place the BL11 into a wallmounted Montana book shelf (69,6 cm x 69,6 cm, divided into 4 differents shelf so the shelf where I would place the BL11 would be around 35x35 cm). It would look really nice below my BS9000 and would also allow me to have some of the CD collection at close hand. Now, my concern is whether this would be an ideal placement for a subwoofer? Or even acceptable? I would probably not have considered it if it had not been in the catalogue.

Any comments, ideas etc. are highly appreciated.

Example of Montana book shelf.

are you thinking of the shelves being only wall mounted ?

I wonder how bass vibrations would affect the screws

or will the shelves rest on the floor ?

I was actually considering the shelf only being wall mounted, about 20 cm above the floor, kind of like a sideboard. Since the subwoofer itself can be wall mounted I was under the impression that there were not that much bass vibrations. Also has a BL2 which I am at least familiar with and which naturally would be a completely different thing.

elephant:

... I wonder how bass vibrations would affect the screws ...

- Isaac Newton (1642 - 1727) observed, force always creates an equal and opposite counter-force.

- Because of the inversely arranged drivers of the BLb 11 all forces and counter-forces transmitted to the
  case/structure af a BLb 11 cancel each other - as a result only the air is vibrating.  

- wall mounting an placing on furniture is therefore possible.

Vienna:

as a result only the air is vibrating.

I am sure you are right, but I do know that at huge volume (66) in action movies I can feel my floor boards vibrate.

Now I will admit that my floor boards are not the best: they are a mixture of repairs on bearers and stumps that have been subject to termites and minor inundations, and so they vibrate even when I walk on them, but then I am ....

... the elephant

Great, potential problem no. 1 solved then. Given the fact that there will be limited space around the sub then - would that cause any potential problems with the sound quality, less bass, too much bass etc.? 

Emil:

less bass, too much bass etc.? 

The wavelengths involved will be pretty huge in comparison to the size of the bookshelf, so I can't see that it's going to cause any issues. I'd put it in a section by itself without any books though...

I am sorry to say this, have being buying B&O for 25 years, I do wonder about some of their products.  Do the BL3's really sound better with a BL11? Visually its a stunning piece of kit, fair enough but that is it for me....

I auditioned them recently and was was not convinced. The BL4000's in a bookshelf sound impressive, or even out of a book shelf.

....beoaus.

beoaus:

Do the BL3's really sound better with a BL11?

Not sure that the BL3s necessarily sound better themselves, but the BL11 cuts off at 33Hz whereas I believe the BL3 cuts off at 50Hz.

(fyi BL2 is 23Hz-120Hz)

Hi,

I would not expect that you would have any problems with mechanical coupling causing your shelf to vibrate. Whether you'll have an acoustical coupling that will cause things to rattle is another question entirely. I would guess (but it's only a guess, mind you...) that you will have vibration issues in the shelf caused by the pressure wave in the air pushing and pulling against the shelf surfaces (both horizontal and vertical). The louder you play, of course, the more this will be true.

The Montana series book shelf is quite solid - we use them in the listening rooms in Struer because (unlike some other brands we tried...) we don't get problems with audible rattling caused by loose shelf components. On the other hand, we don't put subwoofers on them, so you'll be pushing an envelope here...

As for effects on the sound of the BeoLab 11 in a Montana - I'll give it a try in our listening room this week and get back to you.

Cheers

-geoff

elephant:

beoaus:

Do the BL3's really sound better with a BL11?

Not sure that the BL3s necessarily sound better themselves, but the BL11 cuts off at 33Hz whereas I believe the BL3 cuts off at 50Hz.

(fyi BL2 is 23Hz-120Hz)

Hi,

While all these numbers are true, they don't tell the whole story. Yes, BL3 has a low-frequency limit of 50 Hz, but BL11 can play 50 Hz louder than a BL3 can... 

Frequency ranges are measured at a "typical" listening level. However, the maximum sound pressure level available from a given loudspeaker is a different measurement.

So, at a low level, adding a BL11 to a pair of BL3's might not give a huge improvement. However, as you turn up the volume, the advantages are increasingly apparent. (I'm assuming here that you're listening to material with some low frequency content, of course...)

Cheers

-geoff

geoff martin:

While all these numbers are true, they don't tell the whole story. Yes, BL3 has a low-frequency limit of 50 Hz, but BL11 can play 50 Hz louder than a BL3 can... 

Frequency ranges are measured at a "typical" listening level. However, the maximum sound pressure level available from a given loudspeaker is a different measurement.

So, at a low level, adding a BL11 to a pair of BL3's might not give a huge improvement. However, as you turn up the volume, the advantages are increasingly apparent. (Of course, I'm assuming here that you're listening to material with some low frequency content, of course...)

Thanks Geoff for putting the science behind what I believed I was hearing 

All,

Thanks for your valuable input. 

Geoff, many thanks for your comments. It would be really interesting to hear about your findings if you find the time to try the BL11 with the Montana shelf.

Best regards,

Emil

You don't screw them directly into the wall they into the plastic lug which you hammer into the drill hole then screw the screw in

Emil:

All,

Thanks for your valuable input. 

Geoff, many thanks for your comments. It would be really interesting to hear about your findings if you find the time to try the BL11 with the Montana shelf.

Best regards,

Emil

 

Hi Emil,

Well... I gave it a listen in our main listening room in Struer. The setup was two BeoLab3's on floorstands (about 1 m from the wall behind them and 1.5 m from the sidewalls) and a BeoLab11 in a Montana bookshelf (no books - there was no room for more in there...) on the wall behind the 3's. The whole thing was driven by a BeoSystem3 (with an S/PDIF input from my CD player), so it was looking after the bass management. (However, I would not expect any difference if you were doing the bass management inside the BeoLab11.)

The end result? It sounded the same as if I had just placed the BL11 on a wall mount on the same wall. So, this would mean that it's coupling to the room in the same way, and (as someone already mentioned above...) the shelf is small enough so that its resonant frequencies are above the BL11's range. 

HOWEVER...

The bass management crossover for the BL3/BL11 combination is 120 Hz in the BeoSystem3. The Montana bookshelf has a resonance at 297 Hz (I measured...) and the BeoLab11, in External Bass Management mode can go up to 300 Hz - it's left to the external bass management system to limit it.

So, if you set the BL11 to External Bass Management, and your bass management system is set to have a crossover frequency up around 300 Hz, then this positioning will definitely not work. However, if you're doing the bass management in the BL11 or any current B&O device (like the BeoSystem3, for example) then you'll be fine (because the crossover frequency will be in the 80 Hz - 120 Hz territory).

HOWEVER....

One thing I did find out is that we made a small modification to the installation of the Montana bookshelves in our listening room. The backs of the shelves are glued directly to the (brick+render) wall they're hanging on. This prevents rattling between the back panel and the wall itself. If you do not have this "feature" in your installation, then you might hear some rub + buzz from the shelf... I won't make any promises about this.

So, I'd say, give it a try. But if it rattles, don't say I didn't warn you... ;-)

Cheers

-geoff