Hey folks

I hope someone can give me some advice...

I have just moved to a new house and I was initially excited about the prospect of hearing my Pentas in their new room. Previously they were in a room approximately 14ft x 13ft and they sounded awesome. I have them hooked up to a system 5500. The bass was fantastic and detailed - with superb extension down to sub frequencies at some sweet spots in the room. The room was on a first floor with part brick part timber plastered walls and a timber floor.

The new room they are in now is a ground floor room 23ft x 16ft with a concrete floor and aircrete breezeblock walls with plasterboard covering. I was expecting the overall sound to be better all round due to the room's size. However - I am gutted - they sound awful!!!! It's as if someone has literally taken the woofers out. There's almost no bass whatsoever - and what there is sounds like it's coming from some small box speakers. They sound 'lost'. I've tried different positions - distances - all to no avail. Cranking them up makes no difference [:'(]

In another house I lived in with a concrete floor and brick walls they sounded fine. That room was 18ft by 10ft and they were positioned across one of the shorter walls.

I just don't understand it - I'm at a loss [:'(]

Any ideas what could be causing this?

Unlikely perhaps, but is there a possibility they were damaged in transit?

What happens if you turn up the bass control on the amp', do the speakers respond with increased bass? I assume you mean increasing volume when you say 'cranking up'.

Finally, have you just become used to an exagerated bass response as a result of the timber flooring and walls? Concrete will sound very different. I accept that you say they previously sounded 'fine' with concrete, but it's amazing how we can become accustomed to a sound after a period of installation and are shocked by the sound when they are moved location.

I was a bit dissatisfied with the bass on my Beovox Pentas when I moved house, and my new living room is a similar size to your new one. My solution might not work for you as I had the passive versions, but if I were you I'd trash the 5500 system and get a Beomaster 8000 and any sources you want to connect to it, bypass the Lab 150 amps, and hook a Cona up to the Spk2 outlets. Like me, you'll never feel bass-deprived again!

Have you done the connections right?

I'd remove the clothe and would observe the drivers.

After moving my friend's Beolab 6000, they had a horrible sound. It turned out one of the driver had the central "ball" that had been pushed in. We could just fix it by pressing on it.

You can also observe while playing music whether the bass drivers are oscillating at all. Maybe they are disconnected.

My new house is only 300 yards down the road and I was ultra careful about moving them in my car wrapped in duvets. I've checked the connections - all OK and as before.

When I increase the bass on the 5500 - it does increase the higher bass output but not in the lower registers. I think on the 5500 the bass boost is centred around 100hz which I've never liked. It just increases the boxiness of the sound. I always had the bass set to zero - and the pentas bass boost set to +6dB.

What I can't understand is there is just no bass extension below say 80hz. I can see the cones vibrating quite extensively with low / sub frequencies - but it just dissappears somehow and isn't reproduced?! On tracks I know very well with some fine lower frequency bass passages - they are now intensely weak or missing completely. I can neither hear nor feel what I could before. The result is they sound like some small box speakers with little or no bass extension :-(

I'm now sure the construction of the room has something to do with it. Is there any type of construction or material usage that can have such an effect on bass reproduction? Would the plasterboard dabbed onto aircrete blocks cause this? Is there anything I can do to propogate or augment the lower frequencies? I feel like moving again!

It could well be the room acoustics therefore. Not the best of news I'm sure.

When I moved from England to Spain a few years back and connected up my system to my RL60s I was bit shocked by the 'new' sound. The environment had moved from fitted carpets, curtains and a low ceiling to a bigger room, tiled floor with rugs, a fairly high ceiling and plaster walls. Short of changing everything, I've learned to accept it!

RLs not as sophistcated as your Pentas I appreciate, but the same principle nevertheless.

Hi,

First of all, don't doubt your Penta's! They are fantastic speakers and the only thing that can happen to them is foam rot. I think yours is an acoustic problem. Try several positions in the room closer or further from wall/corner. The Beolab amp is the best B&O has ever made and isn't the cause of the problem. They are exactly the diff between Beovox Penta and Beolab Penta and that diff is huge!  Also there are 3 switches on the Beolab and there is one to influence the low frqs. Be patient and try to find the right acoustic position is my advice

All the best and good luck!

BJ

OK - I've carried out some experiments...

Ditched the CD5500 and hooked up my PC via the beomaster 5500 using Winamp to play FLACs.

I've managed to get something resembling low frq's by boosting the 31.5hz EQ slider the full 12dBs! This however overloads the woofers no end to the point of them reaching the ends of their excursion and buckling... I backed off pretty quickly! I could never boost that frequency by more than 2 or 3dBs in my old room as the bass just smothered everything in the frequency range - but in here it disappears!

It is this room no doubt about it. Something about the room is sucking the low frequencies like dracula sucks blood. I think it is the sheer size of the room and the pentas are somehow lost? The concrete floor is carpeted - but with no underlay. I have no furniture in here to speak of yet save a three piece suite and a couple of side tables / TV etc. The room has a fairly low plasterboard ceiling which is 7ft 9in high.

I've experimented with the lab 150s 40hz switch which makes no difference. I've tried different locations - away from - close to the walls - corners - 6ft - 8ft - 10ft - 12ft apart.

Oh my... It just goes to show how a room has MASSIVE effects on the sonic output of a speaker.

Would another pair the other end of the room help matters?!

Thanks by the way for all your replies.

ernie:

First of all, don't doubt your Penta's! They are fantastic speakers and the only thing that can happen to them is foam rot. I think yours is an acoustic problem. Try several positions in the room closer or further from wall/corner. The Beolab amp is the best B&O has ever made and isn't the cause of the problem. They are exactly the diff between Beovox Penta and Beolab Penta and that diff is huge!  Also there are 3 switches on the Beolab and there is one to influence the low frqs. Be patient and try to find the right acoustic position is my advice

The Lab 150 is a fine amp, but it's not the best B&O have ever made by a distance. I think Beomaster/Beolab 5000, Beomaster 4400, Beomaster 6000 (not Quad) and Beomaster 8000 owners would put their amplifiers ahead of the 150 :)

How do you connect Beolab Pentas to a 5500 which has no powerlink sockets?

Do you mean Beovox Penta?

Friedmett:

How do you connect Beolab Pentas to a 5500 which has no powerlink sockets?

Do you mean Beovox Penta?

 

I use the pre-outs on the 5500 straight into the labs line level rca input. Tha labs are set to auto sense. That way I can use high quality cable and phono plugs. I don't bother with the displays.

I'll try some more experimentation tonight with placement etc. I'm hoping some very thick carpet underlay and more soft furnishings might help matters. I think I'm going to invest in another pair too for the rear wall / surround speakers.

I love my Pentas and I'm rather upset by their sound in this room so I'll have to try what I can to improve the situation.

Personally speaking I would postpone any thoughts of rear/surround speakers until you get the 'front' sorted. Adding more speakers will in my opinion just confuse everything, setting back your efforts to achieve a better sound from the Pentas.

Does anyone know what carpet underlay would be best for absorbing / in turn augmenting the lower frequencies? I am not sure whether heavy rubber waffle (130lbs) or the thick but much lighter PU underlay like Cloud 9 Cumulus 11mm - or even the even thicker wool type which it seems have the best thermal (3+tog) and impact acoustic qualities would be better?

It would appear the reason for my bass light situation is due to the concrete structure and its current high reflective properties causing low frequency cancellation. Short of employing large and ugly bass traps - I think I'll try to go down the route of breaking up the reflections by using heavy soft furnishings - starting with the flooring!