B&W CM10 S2 loudspeakers

[jayne lee wilson]

I sold my 25 year old and very heavily used Meridian hi-fi for a brand new Quad system when my late father left me come money. Initially, I was a little disappointed since I was expecting the Quad to be better but, eventually, as the units were used more and my hearing adjusted, I realised that I had been correct in making the change. Although the Quad casings didn't have the quality of the Meridian there was no doubt that the money had been spent on the electronics. Ironically, I sold the Meridian equipment on eBay to a buyer in Germany who paid two thirds of what I had initially paid!

Which Meridians were those, pg? Some of the 80s/90s Meridians were truly beautiful, classics of industrial design....

[Gordon]

I'm sure that both ears getting accustomed to sound as well as the gear bedding in are at work when auditioning and then using new equipment ie new in the sense of new to the listener. But also this phenomenon can continue into the normal working life of the equipment too. For example, rubber/plastic cone surround supports can degrade chemically through gradual decomposition of the material. Similar things can happen with cartridge mounts.

Electronics need less, if any, of this because, unlike speakers and cartridges, there are no mechanically moving parts. Nevertheless amps will produce heat especially if used intensively near their power limits and the music is relentlessly loud eg Rock and will need good thermal design. You can help by making sure amps are well ventilated and perhaps assisted by additional improvised heat sinks [eg a metal bowl of water sitting on top?!? ]. So another factor is to consider how loud your room is when listening "normally". Everything needs to scale to that for a satisfactory result. Normal full range high quality speaker sensitivity is around 90dB [as for these B&Ws] - that loudness is about the level of a noisy diesel truck next to you, a full symphony orchestra at its loudest can reach 120dB, a thousand times the power and equivalent to about an acoustic watt. To replicate that at home [!!probably not comfortable!!] you'll need clean power from the amp of about 100 watts.

If the speakers are a bit on the inefficient side then clearly an amp with plenty of power margin is needed; typical efficiencies are around 5% but some could be as low as 1% - a little less for these B&Ws - that means only one hundredth of the electrical power gets to the air as sound, the rest is heat dissipated in the speaker's wiring. A good design will set the component values to be correct at the working temperature not that of the ambient room. A hot amp will age its components, especially those carrying the power at the output stages and in the power supply itself, faster than one that runs cool. SO, think about valve amps whose heat is obvious and will cook components and cause their values to change.

http://www.sengpielaudio.com/calculator-efficiency.htm

Heat will also degrade speakers if played consistently at their power limits; the voice coils, mounted in very tightly confined spaces, can reach very high temperatures which will not do the rubber/plastic parts much good and can lead to mechanical distortion. Similarly the crossover networks have to carry high currents and although they are easier to cool sustained high power will cause changes in component values over time. One solution is to use more than one drive unit per department but that brings its own design issues. Remember that the amp delivers many watts of power but the acoustic power in the air is relatively small so the excess energy has to go somewhere and that, according to the laws of thermodynamics, usually means heat. Class A design is notorious for heat generation.

Any speaker designer will choose the drive units in relation to the power handling needed - typically the tweeters are loaded a lot less than the main mid range units because there is [usually] a lot less power in the HF. However if your preferred music is rich and is consistently high in HF then the tweeter is likely to get very hot first and the power rating of a tweeter is a fraction of the speaker's claimed power rating. Another thing - an underpowered amp could work at near clipping levels and a clipped audio signal can destroy tweeters!!

[pastoralguy]

Which Meridians were those, pg? Some of the 80s/90s Meridians were truly beautiful, classics of industrial design....

I can't remember the numbers, Jayne, but it was Meridian's reference equipment. I did regret selling them but I was having problems with the CD player which was becoming unreliable in accessing discs. (It must have played 1000's of CDs!)

The big problem was that Meridian refused to service it as they, apparently, had no spare circuitry. There were are a couple of specialist repairers around but they had long waiting lists and the postage and insurance was expensive. (Actually, the number 601 comes to mind). I was scared I might end up with obsolete Hi-Fi equipment and so bought new equipment realising that this would probably be the last time in my life that I'd be able to afford really good units. (Unless my lottery numbers come up!)

I had a pair of ESL 63's at that point so decided to switch to Quad equipment which was ironic since I started having problems with them two years after they had been driven to Quad for a full service. It was a lot of driving and I didn't really want to repeat it! Mrs. PG bought me the Maggie's we have now. (Which were second hand after a wealthy owner had traded them in after 4 months use!)

A friend has a Mackintosh amp and CD player which I'd love to hear rigged up to our Maggies.

[jayne lee wilson]

These? The M 601s were real lookers...

[pastoralguy]

These? The M 601s were real lookers...

Yes! That's the chap. Alas, I never got the volume above 62...

[Eine Alpensinfonie]

Electronics need less, if any, of this because, unlike speakers and cartridges, there are no mechanically moving parts.

Volume controls usually have moving parts and this has always been the thing to go wrong on all the amps I've ever owned.

Crackle... crackle...

[jayne lee wilson]

Perhaps the most visually pleasing (pre-) Meridian effort was the Lecson design that Boothroyd-Stuart collaborated on just before founding Meridian....



this sainted design even appears to have its own halo....

[Tetrachord]

You people really know your hifi!!!

I'm looking at the Densen 410XS compact disc player, but I've found quite mixed reviews on the online forums. Does anybody know anything about this brand because this CD player sure sounded great at the hifi shop on Thursday. One of the negative reviews was build quality, whilst another was length of time taken for repairs. Other reviews were glowing. Repairs can also be an issue if there aren't specialist technicians. Oh dear. Another brand I've explored is the Roksan Candy, which is supposed to be quite good - even though it's not such a good looker!!

Now, with regard to CD players, the dealer said something about 'digital only' or some such. I'm not sure what his qualification referred to, but he seemed to suggest that it wasn't capable of some functions, presumably to do with computer inputs. So totally confusing for me, as I'm a novice.

[Gordon]

Volume controls usually have moving parts and this has always been the thing to go wrong on all the amps I've ever owned.

Crackle... crackle...

True enough EA but that may have been so with older equipment, modern designs don't use mechanical selector switches or tone/volume controls. We had a thread a few months back where I think someone reported a faulty volume control that turned out to be next to impossible to mend!! Was it an ARCAM?

http://www.for3.org/forums/showthread.php?14924-quot-Mucky-quot-input-selector-knob-on-Arcam-Delta-290-amp&highlight=ARCAM

Many amps have remotes nowadays and these set the volume electronically eg using a FET or a voltage controlled amplifier, VCA. If there is a control on the amp itself it will be using a low level DC signal to operate the VCA rather than the audio signal passing directly through the control. Much less likely to cause crackle.

[Gordon]

Now, with regard to CD players, the dealer said something about 'digital only' or some such. I'm not sure what his qualification referred to, but he seemed to suggest that it wasn't capable of some functions, presumably to do with computer inputs. So totally confusing for me, as I'm a novice.

Strange thing to say from a dealer - CD players are virtually all digital [but parts of the playback system are definitely analogue] so it's a puzzle as to what he meant. Perhaps he meant that it only plays CDs and will not take external inputs in other formats like MP3 or FLAC etc via USB? The model 410XS seems to have separate DAC access so perhaps that was what he meant?

The Densen web site's description has some questionable/confusing statements in it and needs a bit of sub-editorial attention [repeated phrase] but if it sounds good why worry.

[johnb]

I'm looking at the Densen 410XS compact disc player, but I've found quite mixed reviews on the online forums. Does anybody know anything about this brand because this CD player sure sounded great at the hifi shop on Thursday.

Just as an aside - if it is at all possible, get the dealer to allow you to try the CD player in your own home.

For most of us it is very difficult to properly evaluate a piece of audio kit in a dealer's showroom/listening room. It is a very different experience to listening in your own home. The differences will include the other items in the playback chain, the furnishings, the size of the room and you will be more relaxed at home. Also, in a dealer's showroom we can sometimes be attracted to the sound of an item but the very things that attracted us to them in the showroom might ultimately make them tiring to listen to in our own home.

[Tetrachord]

Strange thing to say from a dealer - CD players are virtually all digital [but parts of the playback system are definitely analogue] so it's a puzzle as to what he meant. Perhaps he meant that it only plays CDs and will not take external inputs in other formats like MP3 or FLAC etc via USB? The model 410XS seems to have separate DAC access so perhaps that was what he meant?

The Densen web site's description has some questionable/confusing statements in it and needs a bit of sub-editorial attention [repeated phrase] but if it sounds good why worry.

It's the cost mainly, which is over $3,000 AUD. Thanks for the help, though.

[Tetrachord]

Just as an aside - if it is at all possible, get the dealer to allow you to try the CD player in your own home.

For most of us it is very difficult to properly evaluate a piece of audio kit in a dealer's showroom/listening room. It is a very different experience to listening in your own home. The differences will include the other items in the playback chain, the furnishings, the size of the room and you will be more relaxed at home. Also, in a dealer's showroom we can sometimes be attracted to the sound of an item but, when listening to them at home, the very things that attracted us to them in the showroom might ultimately make them tiring to listen to in our own home.

Thanks, that's a good tip and I've read this sort of thing before. Trouble is I do my shopping in Sydney but actually live 130km away from the dealer and it's not so easy to take things on 'appro'. But I might phone him and ask if it's still possible as I'm passing through there in the next days.

[richardfinegold]

#8 richardfinegold and others, my local audio expert certainly believes in "break in" for speakers, and I think also for cartridges. It should, I think, be easy enough to find out if it is the equipment changing the quality of the output as it settles down, or just the owner's ears adapting. Just assemble the electronic equipment (oscilliscopes?) that can display waveforms, and record them every few days from new. If they change, its the equipment breaking in, if they dont its your ears.

I hasten to add that this is certainly not my subject - I'm a biologist - so if this isnt the case, someone who knows please say so.

You may note that I took a neutral position in #8, posing the question only. My own belief is similar to that of Beef Oven, that both the sound of the equipment and the listeners perceptions may change over time.
I believe that the kind of testing sloppy mentions has been done prospectively. Measurements have been taken of gear when it is new, and again after some use when the listener detects a burn in phenomenon, and the measurements haven't changed. Thus the challenge to whether a burn in phenomenon is a real or perceived entity.
However, and as a Biologist I am sure you can appreciate this, sloppy, I am a firm believer that we have not discovered all of the variables that determine how something will sound. Many pieces of equipment, particularly amplifiers, can measure identically, and sound very different. We can measure the variables that we know of, but we can't measure the undiscovered.
As a Biologist you can appreciate the hubris in the belief that we have discovered all the variable that determine sound.
In Biology, new Enzyme systems are constantly being discovered. We have only scratched the surface. In my Profession the explosion of Biologically based treatments has rendered some Medical Subspecialties such as Oncology unrecognizable to me.
And finally, uniting this rambling post about Biology and Acoustics, the Brain is the frontier about which we know the least.
If we could measure a listeners perceptions in terms of changes in Brain Chemistry over time while listening to gear, we could perhaps answer the question

[richardfinegold]

Strange thing to say from a dealer - CD players are virtually all digital [but parts of the playback system are definitely analogue] so it's a puzzle as to what he meant. Perhaps he meant that it only plays CDs and will not take external inputs in other formats like MP3 or FLAC etc via USB? The model 410XS seems to have separate DAC access so perhaps that was what he meant?

The Densen web site's description has some questionable/confusing statements in it and needs a bit of sub-editorial attention [repeated phrase] but if it sounds good why worry.

Agree that is a strange comment from a dealer. If that is representative of his or her knowledge base, tetra chord, you may want to rethink that long commute you make to seek their service .