KEF LS50 disappointment :(

[shkumar4963]

Shkumar, I think port related distortion is a plague on modern speakers. Some ported speakers suffer more from it than others. The LS50's are better than some, eg B&W PM1's, in this respect.

For better bass quality I generally prefer speakers that don't have ports. If you ever get the chance try comparing some properly engineeered sealed box speakers against your LS50's.

I would love to. What speakers would you suggest. I had auditioned PMC 21 and from my recollection, they did not seem to have this smearing. But it is hard to recall and identify unless you were looking for it. And in a 60 min audition I did not notice that either in PMC or LS50s.

Would distortion vs. Frequency grap show that? Can that graph be used to pick this up.

One other issue that I think ported speaker should have is smearing of lower frequency notes. Since resonance will continue a bit longer than the note itself. However, I have not been able to detect it in ls50. If I had a better speaker to compare and I look for it, may be I can pick it up.

What measurement would show that?

Apologize in advance for posing so many questions.

 

[Jota180]

Shkumar, I think port related distortion is a plague on modern speakers. Some ported speakers suffer more from it than others. The LS50's are better than some, eg B&W PM1's, in this respect.

For better bass quality I generally prefer speakers that don't have ports. If you ever get the chance try comparing some properly engineeered sealed box speakers against your LS50's.

I would love to. What speakers would you suggest. I had auditioned PMC 21 and from my recollection, they did not seem to have this smearing. But it is hard to recall and identify unless you were looking for it. And in a 60 min audition I did not notice that either in PMC or LS50s.

Would distortion vs. Frequency grap show that? Can that graph be used to pick this up.

One other issue that I think ported speaker should have is smearing of lower frequency notes. Since resonance will continue a bit longer than the note itself. However, I have not been able to detect it in ls50. If I had a better speaker to compare and I look for it, may be I can pick it up.

What measurement would show that?

Apologize in advance for posing so many questions.

How would you describe the sound of this "smearing"?

I have the LS50's too and on my original stands, with certain tracks, the bass seemed to merge into one long, droning sound. If I turned the sound down it lessened the effect. I tried a load of things from using the bungs to moving them closer to the walls then further away but none of this had much of an effect.

I noticed my stands could move forwards and backwards. If I put my hand on top of the speaker I could rock the stands back and forwards easily so I wondered if that was maybe causing the effect so I took a chance and bought new stands. Once I assembled them the first thing I noticed was how solid they were, nothing like my old ones. Anyway, there was no more droning of the bass notes at all and the difference was incredible.

The mid bass driver must have been rocking their stands almost imperceptibly by sight but most obviously by the sound produced.

 

[shkumar4963]

Shkumar, I think port related distortion is a plague on modern speakers. Some ported speakers suffer more from it than others. The LS50's are better than some, eg B&W PM1's, in this respect.

For better bass quality I generally prefer speakers that don't have ports. If you ever get the chance try comparing some properly engineeered sealed box speakers against your LS50's.

I would love to. What speakers would you suggest. I had auditioned PMC 21 and from my recollection, they did not seem to have this smearing. But it is hard to recall and identify unless you were looking for it. And in a 60 min audition I did not notice that either in PMC or LS50s.

Would distortion vs. Frequency grap show that? Can that graph be used to pick this up.

One other issue that I think ported speaker should have is smearing of lower frequency notes. Since resonance will continue a bit longer than the note itself. However, I have not been able to detect it in ls50. If I had a better speaker to compare and I look for it, may be I can pick it up.

What measurement would show that?

Apologize in advance for posing so many questions.

How would you describe the sound of this "smearing"?

I have the LS50's too and on my original stands, with certain tracks, the bass seemed to merge into one long, droning sound.  If I turned the sound down it lessened the effect.  I tried a load of things from using the bungs to moving them closer to the walls then further away but none of this had much of an effect.

I noticed my stands could move forwards and backwards.  If I put my hand on top of the speaker I could rock the stands back and forwards easily so I wondered if that was maybe causing the effect so I took a chance and bought new stands. Once I assembled them the first thing I noticed was how solid they were, nothing like my old ones. Anyway, there was no more droning of the bass notes at all and the difference was incredible.

The mid bass driver must have been rocking their stands almost imperceptibly by sight but most obviously by the sound produced.

Thanks Jota. My stands are exactly what you described. But I thought it is because they were on carpet. I will put the speakers on the granite counter (island) and see if that improves the sound. It is not that noticeable but may be change in stands will help. What stands did you have and what did you buy later?

 

[Jota180]

Shkumar, I think port related distortion is a plague on modern speakers. Some ported speakers suffer more from it than others. The LS50's are better than some, eg B&W PM1's, in this respect.

For better bass quality I generally prefer speakers that don't have ports. If you ever get the chance try comparing some properly engineeered sealed box speakers against your LS50's.

I would love to. What speakers would you suggest. I had auditioned PMC 21 and from my recollection, they did not seem to have this smearing. But it is hard to recall and identify unless you were looking for it. And in a 60 min audition I did not notice that either in PMC or LS50s.

Would distortion vs. Frequency grap show that? Can that graph be used to pick this up.

One other issue that I think ported speaker should have is smearing of lower frequency notes. Since resonance will continue a bit longer than the note itself. However, I have not been able to detect it in ls50. If I had a better speaker to compare and I look for it, may be I can pick it up.

What measurement would show that?

Apologize in advance for posing so many questions.

How would you describe the sound of this "smearing"?

I have the LS50's too and on my original stands, with certain tracks, the bass seemed to merge into one long, droning sound. If I turned the sound down it lessened the effect. I tried a load of things from using the bungs to moving them closer to the walls then further away but none of this had much of an effect.

I noticed my stands could move forwards and backwards. If I put my hand on top of the speaker I could rock the stands back and forwards easily so I wondered if that was maybe causing the effect so I took a chance and bought new stands. Once I assembled them the first thing I noticed was how solid they were, nothing like my old ones. Anyway, there was no more droning of the bass notes at all and the difference was incredible.

The mid bass driver must have been rocking their stands almost imperceptibly by sight but most obviously by the sound produced.

Thanks Jota. My stands are exactly what you described. But I thought it is because they were on carpet. I will put the speakers on the granite counter (island) and see if that improves the sound. It is not that noticeable but may be change in stands will help. What stands did you have and what did you buy later?

I had a pair of Atacama Nexus 6 for many a year. I tried tightening the screws but couldn't get the stands really solid. I then bought Custom Design FS104 and some mass loading material. I filled the centre columns about two thirds full with the mass loading material. Those stands are incredibly solid with no movement in them whatsoever. The bass was incredible after swapping them over. I tried swapping them back to the old Nexus and the bass loses it's focus and the droning noise comes back at certain volumes.

 

[shkumar4963]

Shkumar, I think port related distortion is a plague on modern speakers. Some ported speakers suffer more from it than others. The LS50's are better than some, eg B&W PM1's, in this respect.

For better bass quality I generally prefer speakers that don't have ports. If you ever get the chance try comparing some properly engineeered sealed box speakers against your LS50's.

I would love to. What speakers would you suggest. I had auditioned PMC 21 and from my recollection, they did not seem to have this smearing. But it is hard to recall and identify unless you were looking for it. And in a 60 min audition I did not notice that either in PMC or LS50s.

Would distortion vs. Frequency grap show that? Can that graph be used to pick this up.

One other issue that I think ported speaker should have is smearing of lower frequency notes. Since resonance will continue a bit longer than the note itself. However, I have not been able to detect it in ls50. If I had a better speaker to compare and I look for it, may be I can pick it up.

What measurement would show that?

Apologize in advance for posing so many questions.

How would you describe the sound of this "smearing"?

I have the LS50's too and on my original stands, with certain tracks, the bass seemed to merge into one long, droning sound.  If I turned the sound down it lessened the effect.  I tried a load of things from using the bungs to moving them closer to the walls then further away but none of this had much of an effect.

I noticed my stands could move forwards and backwards.  If I put my hand on top of the speaker I could rock the stands back and forwards easily so I wondered if that was maybe causing the effect so I took a chance and bought new stands. Once I assembled them the first thing I noticed was how solid they were, nothing like my old ones. Anyway, there was no more droning of the bass notes at all and the difference was incredible.

The mid bass driver must have been rocking their stands almost imperceptibly by sight but most obviously by the sound produced.

Thanks Jota. My stands are exactly what you described. But I thought it is because they were on carpet. I will put the speakers on the granite counter (island) and see if that improves the sound. It is not that noticeable but may be change in stands will help. What stands did you have and what did you buy later?

I had a pair of Atacama Nexus 6 for many a year.  I tried tightening the screws but couldn't get the stands really solid.  I then bought Custom Design FS104 and some mass loading material.  I filled the centre columns about two thirds full with the mass loading material.  Those stands are incredibly solid with no movement in them whatsoever.  The bass was incredible after swapping them over.  I tried swapping them back to the old Nexus and the bass loses it's focus and the droning noise comes back at certain volumes.

Wow. I just finished dis-assembling and re-assembling my stands. No matter what I do, even on a marble floor, they still rock about half an inch. Its natural frequency seems to be about 3 to 5 hz. These are new stands from Sanus (fs26). Now I need to make a decision if the improvement will be enough to warrant another $400 investment in a new set of stands. May be I will look for someone who offers return privileges if there is not much improvement in bass in my set up and room acoustics.

Thanks for your first hand account.

 

[lindsayt]

Shkumar I'd recommend you listening to some sealed box speakers, which pretty much means going for pre 1990's designs as over 95% of modern speakers are ported designs. Bear in mind that you're probably looking at larger bass drivers in a sealed box design to achieve the same measured bass extension as a ported design.

The best way to "measure" flaws in any hi-fi component is to listen to it. Preferably in a level matched demo against something else.

Rudy Bozak used to use single cycle low frequency tone bursts, and a microphone and an oscilloscope to investigate bass transient response in speakers. It's a measurement technique that produces shapes on an oscilloscope, but doesn't produce a number in the same way that a continuous sine wave THD + N measurement would.

 

[Vladimir]

Stack heavy books on top of the stand's footing. If that solves the rocking, you have flimsy stands and need to add weight at the bottom or buy ones with iron cast or granite footing. Filling the pillars with sand and lead shots improves things quite a bit.

 

[shkumar4963]

Stack heavy books on top of the stand's footing. If that solves the rocking, you have flimsy stands and need to add weight at the bottom or buy ones with iron cast or granite footing. Filling the pillars with sand and lead shots improves things quite a bit.

I think the rocking is from the joint between base and pillars. They are joined by one screw per pillar. I see two choices before buying another stands. One is to use four steel ropes to tie the top platform to the base. And two, use some kind of weld or steel glue to fix the joint. The stands are Sanus FS26.

 

[Jota180]

Stack heavy books on top of the stand's footing. If that solves the rocking, you have flimsy stands and need to add weight at the bottom or buy ones with iron cast or granite footing. Filling the pillars with sand and lead shots improves things quite a bit.

I think the rocking is from the joint between base and pillars. They are joined by one screw per pillar. I see two choices before buying another stands. One is to use four steel ropes to tie the top platform to the base. And two, use some kind of weld or steel glue to fix the joint. The stands are Sanus FS26.

That was exactly my problem with the old stands and mine had half an inch to an inches movement too. The only real way of solving it would have been to weld the bloody things! And you don't need to ditch the LS50's for sealed boxes to get tight bass. The bass on mine tightened up massively and it sounds like a different speaker since I got my new stands.

Maybe an idea is to get a couple of solid, heavy slabs like paving stones and place the speakers carefully on them (on bluetac) and see if the bass tightens up. But it's certainly not the speaker at fault for the loose bass. If the CD has tight bass these speakers will reproduce it amazingly for their size. I have a CD, Morphine - At Your Service, Live, and the bass on that is incredible. It was unplayable on my old stands.

 

[shkumar4963]

Stack heavy books on top of the stand's footing. If that solves the rocking, you have flimsy stands and need to add weight at the bottom or buy ones with iron cast or granite footing. Filling the pillars with sand and lead shots improves things quite a bit.

I think the rocking is from the joint between base and pillars. They are joined by one screw per pillar. I see two choices before buying another stands. One is to use four steel ropes to tie the top platform to the base. And two, use some kind of weld or steel glue to fix the joint. The stands are Sanus FS26.

That was exactly my problem with the old stands and mine had half an inch to an inches movement too. The only real way of solving it would have been to weld the bloody things! And you don't need to ditch the LS50's for sealed boxes to get tight bass. The bass on mine tightened up massively and it sounds like a different speaker since I got my new stands.

Maybe an idea is to get a couple of solid, heavy slabs like paving stones and place the speakers carefully on them (on bluetac) and see if the bass tightens up. But it's certainly not the speaker at fault for the loose bass. If the CD has tight bass these speakers will reproduce it amazingly for their size. I have a CD, Morphine - At Your Service, Live, and the bass on that is incredible. It was unplayable on my old stands.

Thanks. That is a great suggestion. I will also see if spotify has Morphine - At Your Service and play it.

I know welding will be messy and will ruin the black finish on the stands. I was also thinking on getting 4 steel ropes and connecting the top plate with base plate with that and tighten the ropes. Kind of the how ship masts are stabilized

 

[bartwuster]

I'm using Sanus SF30 with my LS50 but I didn't notice any movement; just performing well and better each and every day.

 

[Vladimir]

Those are some flimsy stands. Suitable for back surround speakers but not for proper stereo fronts. I would glue every fitting part together, glue lead bits under the bottom footing plate and fill the pillars with sand + lead shots.

1 / 2 / 3 / 4

 

[Jota180]

Those are some flimsy stands. Suitable for back surround speakers but not for proper stereo fronts. I would glue every fitting part together, glue lead bits under the bottom footing plate and fill the pillars with sand + lead shots.

1 / 2 / 3 / 4

You could build bridge supports out of these!

 

[Vladimir]

Only if you don't use the spikes. Otherwise these are the breaking points.

For hardwood floors I really like these due to the inert marble footing.

 

[dim_span]

just get a pair of Partington Super Dreadnaught .... I bought my pair off ebay (and they have been factory filled with the correct resin and silicon-iron damping system and the correct amount

£250 new .... I paid £80 for mine off ebay ... not the nicest looking, but they work well

 

[shkumar4963]

I'm using Sanus SF30 with my LS50 but I didn't notice any movement; just performing well and better each and every day.

That is good to know. If I push on my speakers, it takes less that half pounds of force to move then half an inch. I mean the top plate moves while the base stays at the same place. I feel there is some movement in the joint between vertical tube and base plate.

Can you not move your top plate at all.

 

[bartwuster]

Don't think I can move it, but maybe with super extra force I might able to move it but not with minimum force.

Maybe I'm assembling all the joints with extra force, it seems very solid to me.

As Vladimir wrote, I do fill the pillar with sand to make it firm and heavy.

Sorry if I'm using the wrong wordings as English is not my first language.

Thanks.

 

[shkumar4963]

Don't think I can move it, but maybe with super extra force I might able to move it but not with minimum force.

Maybe I'm assembling all the joints with extra force, it seems very solid to me.

As Vladimir wrote, I do fill the pillar with sand to make it firm and heavy.

Sorry if I'm using the wrong wordings as English is not my first language.

Thanks.

Not even 1/2 inch at the top platform? That is great with sanus stands. But I am surprised.

 

[shkumar4963]

I have kef ls50 and tried one sub sunfire sds 10. The results were not that much better. It seemed that sub is riding on top of the ls50 rather than complementing it. Would love to hear others opinions.

 

[shkumar4963]

I can guess several reasons that may be responsible for me not seeing an improvement when using sunfire sds 10 with my ls50. I will leave to others to comment if my guesses make sense or not.

1. The sub was not well integrated with ls50. I had spend about an hour in order to see if I see any improvement before spending more time. And since I did not see any improvements I dis not spend more time and returned the sub.

2. Sds 10 were of poor quality. A better and more expensive sub may show some improvement.

3. The music that I play does not require much lower frequencies. I can usually get a -3 db response till 50 hz by using equalizer and bass boost with ls50 alone. And that may be good enough for most of my music which is mostly jazz vocals with piano and guitar and occasionally kick drum.

4. I do enjoy clean vocals with not too much bass, especially the kind of bass that ruins vocal clarity.

What I am wondering is if I should give it another try. And if yes, should I try the same or similar sub and try to align it better using REW or get a much better sub before spending more time in it. Would welcome others comments and results using ls50 and a sub or two

 

[hg]

I have kef ls50 and tried one sub sunfire sds 10. The results were not that much better. It seemed that sub is riding on top of the ls50 rather than complementing it. Would love to hear others opinions.

If you are using a normal stereo amplifier rather than an AV receiver then it is the wrong type of subwoofer.

In order to clean up the output from the main speakers and to crossover the subwoofer to the main speakers in the same controlled manner as the midwoofer to tweeter you need to high pass filter the input signal for the main speakers and low pass filter the input signal for the subwoofer. The pair of filters need to match. An AV receiver will do this for you and provide a low passed output to the subwoofer and a high passed output to the main speakers. A stereo amplifier usually will not and so you need the subwoofer to do the filtering and provide a high passed line level OUTPUT to return to the amplifier and pass on to the main speakers. I cannot see such an output on a picture of the plate on your subwoofer and so would conclude it is only intended for use with an AV receiver.

Without the ability to correctly high pass the signal to the main speakers you will have no option but to try to match the low pass for the subwoofer with the natural rolloff of the main speakers. Yuck. You are losing the big wins with a subwoofer which is firstly to clean up the sound from the main speakers by removing the large low frequency motion which is causing intermodulation distortion at frequencies where the ear is sensitive and secondly to replace the sloppy bass from the port with tighter bass from a large cone working comfortably within its operating range.

Subwoofers with the right connections are not expensive. Here is an example that is half the price of your subwoofer. This is not intended as a recommendation but to show that suitable subwoofers are not expensive.

PS I have now seen a photo that shows line level outputs. So slightly confused. Did your subwoofer have them and did you use them?

 

[shkumar4963]

The amplifier did have a sub out and that is what I had used. Xover was fixed at 90 hz.

 

[shkumar4963]

HG: I checked out the sub that you mentioned. It seems to be good but that raised another question. How to check the quality of the sub before buying.

I have seen that pricing of subs are from 300 to 3000 dollars and the price often does not seem to link with any published parameters like amp power, speaker diameter etc.

 

[shkumar4963]

Can I use PEQ to lift bass response of a standmount speaker? If yes, what is the limit of this approach? How much increase at lower frequencies (in db) is accoetable? For a speaker with -6db point at 50 hz and -12 db at 32 hz, can I raise 12 db using PEQ for a flat frequency response till 32 hz. That would be sufficient for all kind of music except for home theater. one negative could be danger of burning the speaker by pumping so much energy in the speaker at that low frequency. How do I estimate what is the max energy I can put in the speaker safely? For average music listening levels ( about 86 to 90 db at 1 m), is there a danger for kef ls50.

 

[Frank Harvey]

I have never been impressed with Sunfire subs. They play loud and produce quite an output for their size, but their bass seems very limited in range - in other words, they sound more like car subs that are tuned to one frequency. If a sub is a genuinely good sub, there shouldn't be too much of a problem integrating it with a pair of speakers.