I'd keep it, but you need a decent-sized room really to get any benefit from an amp with 150w p/c. Either MC120.2s or S120s would be a good match (i.e. the BM8000 won't fry them above 2.5). I use Beovox Pentas personally with mine, but they're not going to fit on a bookshelf I'm afraid. The MC/S 120s would though.

Hi there,

This is more a question for my own better understanding, but perhaps would assist Durr in the selection of the speakers too .....

My understanding is that the B8000 is rated at 150W at 4 ohm and 100W 8 ohm... now based on this the 8 ohm MC120 would be perfect as you suggest John. Also how about the CX100 (although limited sound quality I'm sure) could this also handle the BM8000 ? 

Now also what about some of the slightly earlier speakers such as the  S75 / M75 these had variable impedence 4 - 8 noted in the old catalogues they also give 2 ratings, RMS and Music load.... in the case of the above they are rated RMS 75 (not sure at what impedence)  and music loads of over 100W. So would these handle the BM8000 too? When I was looking for what became the BM6000 I have, I considered long and hard the BM8000 and one of the dealers I spoke with had suggested the above speakers could be matched as long as I didn't play at 'full volume'... So I'm interested to know if this would have been correct and workable option...

Thanks,

Laurence.

Unless you like it really, really loud, it's actually easier to damage your speakers with a smaller amplifier than with a more powerful one. Why? Well, when you reach the limit of your amplifier, it will distort a lot and this (clipping-)distortion contains a lot of nasty high harmonics with lots of energy and that can destroy the tweeters.

Remember that the actual sound level that a speaker produces at a certain volume setting of the amplifier does not correlate to the speakers watt rating. The watt power rating only tells you how much power the speaker can handle, not how loud it plays. What matters here is the speaker's sensitivy - how loud the speaker sounds at a certain input level (for example: 89 dB (at one meter's distance from the speaker) when fed with a 1 watt signal). This sensitivity does not correlate to the watt rating, instead it has to do with the speaker construction - bass reflex (ported) design vs closed box, impedance behaviour, crossover circuit and much more.

Impedance is also important - What you see in the specifications of a loudspeaker is its nominal impedance, but in the reality the impedance is different at different frequencies.

If you listen at "normal" sound levels, your amp outputs, let's say, 10-15 watts at most. A signal that a speaker with a 40 w rating can handle just as well as a 150 w speaker. However, if you crank the volume up real loud the 40 w speaker will be damaged earlier than the 150 w speaker. From the department of bad analogies: a frying pan with a teflon coating and a die-cast iron frying pan may both be used at low to medium temperatures. You may have to crank the the knob on the stove a bit more with one of the pans in order to reach the same frying result - that pan is less sensitive than the other, it is not as efficient. As long as the stove can handle this, no problem. Both pans may be able to give you excellent and similar results at modest temperatures. However, those moments when you need the pan to get really hot you have to take a look at the rating o the pan - the teflon pan will be damaged at a lower temperature than the die-cast pan. The important thing here is that this does not affect how it performs at moderate temperatures. It's kind of the same with speakers and watt ratings, but please don't place the speaker on the stove.

I have two bm8000s - one is used with cx50s (works fine, but of course I don't use this combo as a disco pa system :-) ), and one is used with a pair of s 45-2s. The latter system can go quite loud, no problem. I actually trust it more than I trust my bemoaster7000-m150 combination that I also have.

We should produce som kind of FAQ item for power-rating questions.

Agree completely with above. However I use mine with M100s and it is wonderful! Not many systems can drive really big speakers well and you have one that does. A good big one will beat a good small one any day! The big speakers will give you better bass response and also, if chosen correctly, more bass detail.

Hi Henrik,

Thanks for your detailed reply. Yes I think a FAQ page perhaps  about speaker / amp ratings / compatibility would be excellent idea especially for people such as myself that are less experience and technically minded.  Because I think what those less experience tend to do is think that we should match the amp to the speaker exactly eg. BM 8000 / M150 or BM6000 / S80 etc for instance ...

This lack of knowledge, held me back from trusting this dealers advice, he (in his own words of course) was a collector and enthusiast, and I'm sure was very experienced, but I opted for the trusted matching system I referred to above as I was unsure ... this in the end also affected my decision to get the 6000 over the 8000 as I didn't want to have the the large M150 / MS150 speakers in my living area (and of course the cost of shipping them) .... If I had known I could have used smaller rated (and dimensioned) speakers safely with the 8000 then the outcome may have been different 😳 .... Not that I am disappointed with the 6000 of course, I love it ... 😁

In your experience with the 8000 and the S45.2 when you say loud is it 50% of total volume scale? For instance at 30/35 or 50% of the volume on the 6000, this is really quite loud and by 40 has approached 'party volumes'... would this be comparable? I could not imagine going anywhere near maxing out ( at 60) the volume on my system.

Well, thanks again and I'm sure your input will be very helpful and enlightening to those considering putting together a system  ...

Laurence..

Well I use Beovox M150 with my Beomaster 8000 and they can handle the output at any volume.

Even though I got Beovox S120 last year I never thought they were that suitable for an 8000 as Dillen has given me a 2*192 in real speaker output power which he has measured while working on them.

The Beovox S80.2 is a little less but for my S peakers they go with a Beomaster 6000 and that's it.

As for Beovox S45-2 I would not use them with either Beomaster.

As for size there is not alot of difference between my S speakers and M150's. The MS150 is just taller but it's the same space they take.

S45-2s are safe with the BM6000 - they will take peak power of 75W so as long as you don't turn it up to 10 and leave it there, you will be fine.

There has to be a bit of sense used with these matters. As said above, most damage done to speakers is caused by little amplifiers distorting into speakers. Most music we listen to will use very little power - probably less than 3W. It is the transient peaks that you need the power for so you have plenty in reserve. This has always been a good point of B&O amplifiers. I use a Beomaster 4400 which has a peak power output of well over 100W per channel and use BBC LS3/5A speakers with it which is supposed to be limited to 25W. No problems at all and I know of plenty of people who use even more powerful amplifiers with them.

If you are concerned still, just get speakers with a protection circuit built in , though I think this is unnecessary.

Each to their own I suppose. The way I look at it is that the Beomaster 8000 was a top-of-the-line product that was meant to be used in large spaces and had to be capable of playing at high listening volumes without distortion if required. I have a large living room, and I like listening to music at high volumes on occasions, so I use Beovox Pentas. I could use MC120.2s, but I don't think they'd fill the space with sound as well as the Pentas. I'm sure MS150.2s would do the job nicely as well. Equally, I'm 100% certain that if I replaced my Pentas with some CX100s I would be extremely disappointed with the results. If I carted the whole lot upstairs and set it up in my home office, I'd probably be satisfied with the CX100s and think the Pentas were too much. 

If you're planning on using your BM8000 in a big space, get some big speakers as the manufacturer intended.

If you're planning on using your BM8000 in a small space, use some smaller speakers if a big sound is not required (or perhaps just get a smaller amp - what's the point in having all that power with no way of burning it?)

Hi Peter,

Thank you, this again I find very helpful, as I am still trying to better understand the concept that you don't necessarily have to match the amp power output with the speakers... and for most of us as you say, we probably generally only use our systems at much lower levels than they are capable of, in my case probably around 30% of its full potential... 

Hi John,

I do actually agree with you here, this was another reason why I opted not to get the 8000 as I felt it was too powerful for the space in which I was going to place it ... altho I very much liked the idea of the unit, being the flagship and also being considered one of the best amps B&O have ever made... so I still occasionally yearn for one, especially when I see someone in the forums have gotten one at a steal and are restoring it...😮

Thanks,

Laurence