KEF LS50 disappointment :(

[BigH]

But Neumann seem to be active speakers?

I am intrigued. Why do you think that might be relevant when it comes to getting a feel for the SPL that various driver configurations can produce?

Neumann speakers obviously perform well or else they would not publish reasonably full specifications but other good quality speakers will be in the same performance ball park.

because active speakers generally have much lower distortion than passives, there are other factors to consider as well. Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m? The KH120 only use 50w amps.

 

[hg]

because active speakers generally have much lower distortion than passives, there are other factors to consider as well.

What makes you think that active speakers may have much lower distortion than passives? If this is the case why do you think home audio speaker manufacturers would not adopt them?

Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m?

The sensitivity of the LS50 is quoted as 85dB for 2.83V at 1m. If the speaker is nominally 8 ohms then that would be give 85dB at 1m. for 1W input. At 2m this would be 79dB for 1W input. A doubling of power will increase the SPL by 3dB and so you would need 4W to get 85dB at 2m.

 

[Frank Harvey]

Jack said the LS50 dual concentric driver is a modified Q100. That would explain the shared performance margins.

Well if Jack didn't make a mistake, then they must've used an R100 cone in a Q100 gasket...

 

[BigH]

because active speakers generally have much lower distortion than passives, there are other factors to consider as well.

What makes you think that active speakers may have much lower distortion than passives? If this is the case why do you think home audio speaker manufacturers would not adopt them?

Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m?

The sensitivity of the LS50 is quoted as 85dB for 2.83V at 1m. If the speaker is nominally 8 ohms then that would be give 85dB at 1m. for 1W input. At 2m this would be 79dB for 1W input. A doubling of power will increase the SPL by 3dB and so you would need 4W to get 85dB at 2m.

I have read article about it. Manufacturers are beginning to produce actives, Kef is one, believe AE are producing a new range soon, PMC do, see their video about active. But one reason is because they would not be popular with some hifi dealers and amp. manufacturers, think about it. I think one of the biggest causes of distortion is the passive crossovers. Why are they used in studios so much, because they can play at loud volume without much distortion and are generally less coloured?

 

[Frank Harvey]

KEF quote maximum SPLs of 104dB and 106dB without specifying the conditions. This does not look like a significant difference.

That must mean they're pretty much the same then. Funny how specs matter when it's appropriate.

This is not correct. Our hearing is non-linear and the level we listen at significantly changes the tonal balance we perceive.

I fully agree.

This is why the film industry specifies the playback level so people hear what was intended.

They're recommending you listen the multiple (calibrated) channels at the same volume as they were mixed at in order to hear the mix as it was intended. Levels for movies need to be standardised for various reasons, both in the theatre and in the home.

The same is true for music and if people wants to hear what was intended one of the criteria that must be met is an undistorted playback level somewhere around the reference level.

I have never read anywhere about any sort of "Reference Level" existing for home audio to reproduce music.

If this is true, this means that anyone out here listening to music quietly, YOU'RE LISTENING WRONG!! You MUST listen to music at 85dB! *acute*

 

[BigH]

The sensitivity of the LS50 is quoted as 85dB for 2.83V at 1m. If the speaker is nominally 8 ohms then that would be give 85dB at 1m. for 1W input. At 2m this would be 79dB for 1W input. A doubling of power will increase the SPL by 3dB and so you would need 4W to get 85dB at 2m.

So with an average amp. say 60W per channel they should be loud enough for most people at 3m. In my demo of LS50s I did play them quite loud and I was about 4m away, louder I than I normally listen at, I did find that at lower volumes they did not sound that good. I did not buy them, I thought the actives speakers I have are much better for me, the sound does not really change at different volumes, just louder or quieter. And yes they can be very loud and its not distorted but the amps are 250w for bass drivers and 100w for tweeters.

 

[Frank Harvey]

I have read article about it. Manufacturers are beginning to produce actives, Kef is one, believe AE are producing a new range soon, PMC do, see their video about active. But one reason is because they would not be popular with some hifi dealers and amp. manufacturers, think about it. I think one of the biggest causes of distortion is the passive crossovers. Why are they used in studios so much, because they can play at loud volume without much distortion and are generally less coloured?

Because they're more convenient. They don't want amplifiers lying about the place as well as the speakers.

 

[shkumar4963]

So while small speakers can not compete with larger ones in sound quality, can we say that LS50 are the one of the best speakers for that size and for that price ($1500)?

If not what would you prefer instead in the same or similar size and same or similar price?

And then what about Stereophile ranking them as Class A speakers?

 

[Vladimir]

Well if Jack didn't make a mistake, then they must've used an R100 cone in a Q100 gasket...

It's a family of drivers. Q100 is the daddy, R100 and LS50 are the offspring. This driver lineage is from the Andrew Jones days at KEF 30 years ago (Uni-Q).

There are 5.25, 6.5 and 8inch Uni-Q driver in the Q range. This discussion is focused on the 5.25inch which is used on the Q100 and Q500.

The driver in the R100 is based on the Q100 driver but has a different cone (which you can identify the driver by from the font) and some tweaks to the tweeter and midrange magnet systems to reduce the distortion (addition of shorting rings and a copper cap).

The LS50 driver is a special edition of the R100 driver with a different voice coil spec (to give a slightly different bass response in the system). The surround is also different and gives a slightly tidier upper MF response. We slightly adjusted the geometry around the tweeter magnet OD, also to improve the MF response.

 

[matthewpiano]

There are some things, such as imaging, that small speakers do better than floorstanders. Sound quality isn't only about SPL and frequency response.

 

[lindsayt]

because active speakers generally have much lower distortion than passives, there are other factors to consider as well. Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m? The KH120 only use 50w amps.

A pair of LS50's will produce about 94 dbs at 2 metres with 10 watts input.

http://myhometheater.homestead.com/splcalculator.html

You are also wrong about active speakers generally having much lower distortion than passives.

I'd be happy to explain why in a separate thread. Discussing it here would just totally derail this thread.

 

[BigH]

There are some things, such as imaging, that small speakers do better than floorstanders. Sound quality isn't only about SPL and frequency response.

I agree, some floorstanders are terrible, cabinets vibrating, boomy bass etc. I don't think I would touch any under £1,000. Just because drivers are in a larger cabinet, which due to physics causes more problems than smaller cabinets, will not necessarly make them better. More drivers more crossovers, more difficult to integrate. There maybe more bass from the larger cabinet but in some rooms that can cause problems.

Matthew you changed your speakers again?

 

[Vladimir]

@skhumar

I'd rather get a pair of B&W 805s. Unless you insist on a pair of KEF 107/2. *biggrin*

@matthewpiano

Reduce the bass tone controls on a floorstander and you get the same effect.

 

[hg]

So with an average amp. say 60W per channel they should be loud enough for most people at 3m.

Who are most people?

Hi-fi enthusiasts can be expected to playback somewhere around reference levels and the LS50 with a 60W amplifier is well short of being able to reproduce musical peaks cleanly at this level at 3m. They would however be able to reproduce the average level and so would tend to sound loud enough just not clean enough for high fidelity reproduction.

 

[matthewpiano]

Not really. Run 2 systems so still using the Dyns. The Q100s work particularly well with the Exposure amp.

 

[matthewpiano]

@skhumar

I'd rather get a pair of B&W 805s. Unless you insist on a pair of KEF 107/2. *biggrin*

@matthewpiano

Reduce the bass tone controls on a floorstander and you get the same effect.

No, you don't.

 

[BigH]

because active speakers generally have much lower distortion than passives, there are other factors to consider as well. Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m? The KH120 only use 50w amps.

A pair of LS50's will produce about 94 dbs at 2 metres with 10 watts input.

http://myhometheater.homestead.com/splcalculator.html

You are also wrong about active speakers generally having much lower distortion than passives.

I'd be happy to explain why in a separate thread. Discussing it here would just totally derail this thread.

OK thats even better, 94db seems pretty loud to me, at 50ws, 102db.

I look forward to your post about active/passive distortion.

 

[steve_1979]

There are some things, such as imaging, that small speakers do better than floorstanders. Sound quality isn't only about SPL and frequency response.

Just what I was about to say.

Compact 5" two-way speakers often sound better than larger two-way speakers in the mid-range/treble frequencies because a small 5" driver is able to have a higher crossover frequency which means that both the mid/bass driver and tweeter are able to cross over at a more suitable frequency without needing to be pushed into cone break up. Their stereo imaging is often sharper too.

Compact 5" speakers tend to do an awful lot very well and are often well suited to the acoustics of small European rooms. Just don't expect deep bass and high volume levels (you need big drivers and enclosures for that).

 

[Vladimir]

I agree, some floorstanders are terrible, cabinets vibrating, boomy bass etc. I don't think I would touch any under £1,000. Just because drivers are in a larger cabinet, which due to physics causes more problems than smaller cabinets, will not necessarly make them better. More drivers more crossovers, more difficult to integrate. There maybe more bass from the larger cabinet but in some rooms that can cause problems.

Dude...

Checkout the measurements from the R500s and R700s. They are immensely better than the standmount. Those darn laws of physics mess with audiophile small form factor fetish as usual.

Just look at these photos. Why would you want the LS50 over this?

 

[hg]

There are some things, such as imaging, that small speakers do better than floorstanders.

Why do you consider small speakers to be better at imaging?

 

[steve_1979]

Just look at these photos.

 

[shkumar4963]

because active speakers generally have much lower distortion than passives, there are other factors to consider as well. Correct me if I'm wrong but ls50s with 10w would produce 85db at 2m? The KH120 only use 50w amps.

A pair of LS50's will produce about 94 dbs at 2 metres with 10 watts input.

http://myhometheater.homestead.com/splcalculator.html

?

You are also wrong about active speakers generally having much lower distortion than passives.

I'd be happy to explain why in a separate thread. Discussing it here would just totally derail this thread.

Please start a new thread.. please liberal with quoting reputed technical papers so that I can learn background details.

 

[steve_1979]

There are some things, such as imaging, that small speakers do better than floorstanders.

Why do you consider small speakers to be better at imaging?

Less phase distortion due to there being less cone breakup (see my post above) and the smaller narrower enclosures suffer less from edge diffraction than larger wider enclosures.

 

[BigH]

I agree, some floorstanders are terrible, cabinets vibrating, boomy bass etc. I don't think I would touch any under £1,000. Just because drivers are in a larger cabinet, which due to physics causes more problems than smaller cabinets, will not necessarly make them better. More drivers more crossovers, more difficult to integrate. There maybe more bass from the larger cabinet but in some rooms that can cause problems.

Dude...

Checkout the measurements from the R500s and R700s. They are immensely better than the standmount. Those darn laws of physics mess with audiophile small form factor fetish as usual.

Just look at these photos. Why would you want the LS50 over this?

Are they under £1,000?

Yes more expensive floorstanders can be better depending on your room. Why would I want the LS50s probably because they are about £700. How much are those speakers?

 

[shkumar4963]

There are some things, such as imaging, that small speakers do better than floorstanders.

Why do you consider small speakers to be better at imaging?

Probably because of localization of sound from a single location or small location.

Floor standers with long array of drivers loose that.