I have seen a lot discussed on these two speaker. However, I was wanting a precise comparison on why BeoLab 4000 are superior to BeoLab 2500 ( As per the Majority, there may be very many out there arguing otherwise).

Form a very simple comparison of the technical numbers I note that both are quite even - with yellow shaded indicating 4000 being higher. I would like to see fellow members to mention the difference or reason for the superiority of 4000's. 

Maximum Sound Pressure Level (stereo, pair) 98 dB -Vs- 97 of Beolab 4000

Long-term maximum output power per module* 65 watts - Vs- 59 of  Beolab 4000

Magnetic shielded No -Vs- Yes of  Beolab 4000

Woofer 11cm -Vs- 11 of  Beolab 4000

Tweeter 2.5 cm -Vs- 1.8 of  Beolab 4000

Net volume 2.8 litre - Vs- 4 of  Beolab 4000

Thanks all

Beolab 4000s completely outperform 2500s. The larger volume means that the bass response is much less dependent on changing the characteristic of the amplifiers. The tweeter is also a better quality item. The bald figures show why it is important to listen to speakers!

For the 4th or 5th time in the last 5 minutes I'll echo Peter here that the proof of the pudding is in the eating! Whatever the spec sheet says your ears will tell the final story. No listening test would ever place the 2500s above or near the 4000s.

Why bother with a listening test then if it is as you state?  Some people may prefer the 2500's to 4000's, are they to feel they are wrong in some way?  People tell me that 5's are better than 9's, I differ.  The general consensus is not to have a Beolab 2 with 9's, I differ there as well.

The sound.

Years ago I had the same question. My initial attraction to the BL 4000 was the design and shape.  My B&O salesman (long since moved on) gave me a demonstration of the BL 4000 which was impressive. I then asked how the BL 2500 speakers compared.

Not saying a word, but raisiing his eyebrows, he motioned me over to another system with BL 2500. The sound was not as full, and not as clear, and set of gold BL 4000 were ordered from Danemark. They later arrived with covers for some reason, which I gave to the store. I've changed the outside colours twice, and even now I continue to use them today.

The BL4000 MKI, in my opinion are the greatest active speaker B&O have ever done in terms of sound quality, tone, value and beautiful design... Only surpassed by BL5

I feel like a broken record touting the BL4000's, but everyone should have a pair!

Its very interesting so far to read the responses. I have been my self a strong beleiver in listen and judge rather than decide on credentials. However, its so fascinating to see how staunchly many support the 4000's specially MK1. For some reason MKII do not have the same following. I guess upgrade is not always improvement in performance!!

Now the real question is what makes them sound so better than 2500. Is it the shape of speaker or increase in net volume or better electronics inside the speaker. This might be a bit more to ask.

Keep your posts coming

Notice Dave it quite into BL4000's.... Must say that of all the B&O speakers I have owned and listened to the BL4000's have surprised me the most. The reason they do so is they just work anywhere. Not sure if its the components, size of the cabinet or magic elsewhere, I can just listen to them next to my computer, 50cm's away, on a roof as surround speakers, in front as primary speakers in a party, jammed against a wall, one in a bookcase and at very soft volumes the sound is stll full and complete... Versatility personified.

...

The 2500's do sound pretty good in a well designed setup, not so well in a less perfect enviornment.

beoaus.

Having had both, I enjoyed them both, but as others said, the Lab 4000 sounds better than the 2500.

I've always been a fan of tech specs, but in this case, believe me, there is little difference on the spec sheet, but a much wider difference when listening.

The 2500 were a little revolution when launched, but the 4000 were launched later on, so had to be more advanced in every way:

- bass is deeper (55 Hz is quoted on both spec sheets, but so is Lab 6000, which actually goes down to 70 Hz only)

- treble is much more detailed

- same for midrange (the 2500 have a more loudness-type sound, so you lose on the medium)

- the 4000 is shielded, the 2500 is not

- the 4000 has numerous placement options, the 2500 has one

- the 4000 has a metal finish, the 2500 is all plastics

- phono & 2 Powerlink inputs, the 2500 only has 1 Powerlink input

- the 4000 has 4 liters volume, the 2500 has less

In theory, if you want to compare the 2500 to something else nowadays, it has to be BeoLab 4.

Chrisreunion:

In theory, if you want to compare the 2500 to something else nowadays, it has to be BeoLab 4.

Good point!

I am a 4000 fan too! Best bang for the buck in the modern active range. Modern S45's if you like... 

Very well said. I agree with you on the Lab 4 comment.

If comparing the original cost of the BL4 and 2500, yes they both are/were the Beolab entry level... but their sound characteristics couldn't be more opposite. 

The BL 2500 are warm and organic sounding with soft highs while the BL4 have no warmth but great transparency and sharp highs.

They sound as different as they look, two worlds apart

As stated above, the specifications mean nothing! I get to use lots of different studio monitors, Genelec, Adam, Mackie etc. In many ways, the speakers which don't measure out the best often sound the best.

Genelec for instance spend a lot of their time fine-tuning their speakers in an anechoic chamber/scientific lab, whilst Adam do a lot of tuning by ear. I know which I'd rather listen to (and I use both on a daily basis), and which are better at their job; the Adams every time!

The same goes for B&O's speakers. Specifications can lie. Is the SPL of both speakers calculated, or actually measured? What's the %THD at those SPLs? What about the frequency response - are they both measured within the same tolerances (ie, -3dB, -6dB, -10dB)?

Most importantly, wattage doesn't mean anything!!

Questions should be "What makes the BL2500 superior to BL4000"!!!

I`ve had the BL2500 together with the BS2300 for more then 10 years placed on the wall. Maybe it was a top setup, but there was not a single day I was dissapointed (sound and style). I only have had the chance to compare BL2500 next to BL4000 in a B&O shop and of cause it was years ago. I think, I was not very impressed.

You could never ever compare the BL2500 to the tiny PC BL4.

The BL2500 is a killer (budget, style) if you place it together with a BS2300/3000/3200.

It was my first and my best B&O equipment. Shame on me I`ve sold it.

I would not hasitate a single moment if there is a "new" BL2500/BS3200.

I would rate the BL2500 over BL4000, if you owe a BS2300/3000/3200, have limited space/money regarding sound and style.

I would have thought BL4000 would sound better due to more volume in the cabinet etc. Also the ability as previously commented to place them wherever you want a create a large soundstage. They look better than than the 2500 when on their stands either side of a BC3000 etc. 

However I don't agree that they are the best speaker in terms of value for money. I bought some S60's off ebay and an MCL2P, about £100 in total - this totally, imho, outperforms the BL4000's in terms of bass, clearness etc. But then it is all subjective and what one person likes another may not. To make matters worst the S60's hooked up to a BC7700 sound even better than they do through the MCL2P - I don't know if it is because they are being fed from an Avant. The BL4000 are used as rear speakers now with the S60's as front. All four of them on for Music actually sounds quite good.  

Why should the markII beolab 4000 sound worse than the mark I?

Compared to the recent make-over of the beolab 6000 -> 6002 the sound is descibed as improved. Same sort of make-over isn't it?

ajames:

I would have thought BL4000 would sound better due to more volume in the cabinet etc. Also the ability as previously commented to place them wherever you want a create a large soundstage. They look better than than the 2500 when on their stands either side of a BC3000 etc. 

However I don't agree that they are the best speaker in terms of value for money. I bought some S60's off ebay and an MCL2P, about £100 in total - this totally, imho, outperforms the BL4000's in terms of bass, clearness etc. But then it is all subjective and what one person likes another may not. To make matters worst the S60's hooked up to a BC7700 sound even better than they do through the MCL2P - I don't know if it is because they are being fed from an Avant. The BL4000 are used as rear speakers now with the S60's as front. All four of them on for Music actually sounds quite good.  

The amplifier in the 7700 is better than the MCL2P. The 7700 really is a superb machine - in some ways it can be regarded as a music centre 8000 system.

I think speakers are very individual choices - I too like S60s - lots of detail and plenty of bass. I agree that they out perform 4000s. I think with the right amplifier that they outperform 8000s as well ....