Troubleshooting bad sound

For a few weeks now, since the arrival of dreadful humidity, the sound out of the speakers, especially at high voume is sounding very ordinary.

- Wooly bass

- Mids, hardly present

- Treble has lost definition

- Image suffers, especially beyond the left and right boundary

Thoughts turned to pre-amplification, was the power amp driven enough, lost control somehow? Maybe with the humidity, the speaker drivers are covered with moisture. Umm, these drivers are plastic, and a fibre, so no liquid cleaning there, just dusting off.

Well.

The mid on the KEF 205/2 has the tweeter as a centre piece, and this was coated with fibres/dust. Brushed this off with a make-up brush, it's super soft and removed all the rubbish. Ports could do with a wring out with microfibre cloth. Done. The rubber was still in good condition, for a speaker 10 years old is good to see.

The drivers are mounted with M4 (mid/Tweeter) and M5 cap screws (two woofers), these are usually metal threads, let's see if they are tight. Oh dear, there was a full two and a half turns to make the screws snug on all drivers. It felt like the screws are pulling on a metal ring or structure, not wood, thank goodness.  Was a bit late at night to wake up the neighbourhood,  left the amp running on Tuner at very low volume, just for the exercise.. Today, the sound emanating from the speakers is:

- Bass tight, McCartney's bass on Mrs. Vandebilt is very tight, wooliness is gone

- Mids/Vocals clear as a bell

- Imaging back, nice front to back, height dependant on recording

- None of that honking any more

It would appear the speakers not tight in the enclosure were moving about creating extra vibrations whatever they wanted to do.  Pure friction held them in place.

If you have speakers even 5 years old, worthwhile the check the mounting screws, very little work to tighten these, the bonus of a great sounding speaker like when it was first delivered and cost $0 for the 'upgrade' !

This is a good photo, the mid has the three M4, and M5 on the woofer.

First - do these have ferofluid tweeters? If so that can be part of the tweeter issue. Ferrofluid evaporates over time.

17 hours ago, One and a half said:

For a few weeks now, since the arrival of dreadful humidity, the sound out of the speakers, especially at high voume is sounding very ordinary.

 

- Wooly bass

- Mids, hardly present

- Treble has lost definition

- Image suffers, especially beyond the left and right boundary

 

Thoughts turned to pre-amplification, was the power amp driven enough, lost control somehow? Maybe with the humidity, the speaker drivers are covered with moisture. Umm, these drivers are plastic, and a fibre, so no liquid cleaning there, just dusting off.

 

Well.

 

The mid on the KEF 205/2 has the tweeter as a centre piece, and this was coated with fibres/dust. Brushed this off with a make-up brush, it's super soft and removed all the rubbish. Ports could do with a wring out with microfibre cloth. Done. The rubber was still in good condition, for a speaker 10 years old is good to see.

 

The drivers are mounted with M4 (mid/Tweeter) and M5 cap screws (two woofers), these are usually metal threads, let's see if they are tight. Oh dear, there was a full two and a half turns to make the screws snug on all drivers. It felt like the screws are pulling on a metal ring or structure, not wood, thank goodness.  Was a bit late at night to wake up the neighbourhood,  left the amp running on Tuner at very low volume, just for the exercise.. Today, the sound emanating from the speakers is:

 

- Bass tight, McCartney's bass on Mrs. Vandebilt is very tight, wooliness is gone

- Mids/Vocals clear as a bell

- Imaging back, nice front to back, height dependant on recording

- None of that honking any more

 

It would appear the speakers not tight in the enclosure were moving about creating extra vibrations whatever they wanted to do.  Pure friction held them in place.

 

If you have speakers even 5 years old, worthwhile the check the mounting screws, very little work to tighten these, the bonus of a great sounding speaker like when it was first delivered and cost $0 for the 'upgrade' !

 

This is a good photo, the mid has the three M4, and M5 on the woofer.

 

 

 

 

Guess we could all use a bit of dusting off and tightening up with the passing of years ! Well done 1.5

On 2/15/2024 at 2:05 AM, botrytis said:

First - do these have ferofluid tweeters? If so that can be part of the tweeter issue. Ferrofluid evaporates over time.

I am not sure, so googled ferrofluid tweeters with KEF. It appears that the 100 series did have the ferrofluid concept for the tweeters. For the 200 series, the Uni-Q design was adopted. The manual doesn't refer to ferro anywhere, ferro and Uni-Q seem to be mutually exclusive. 

If the tweeter did lose any fluid, fragments would have certainly ended up across the room by now. I bought these used as demo stock and have been very faithful to the sound, better amps and more importantly better sources (=lower noise) is noticeable.

For the future, looking for used Blades or Sony SS-AR1, for the time being though  the 205/2 will be great companions.

8 hours ago, One and a half said:

I am not sure, so googled ferrofluid tweeters with KEF. It appears that the 100 series did have the ferrofluid concept for the tweeters. For the 200 series, the Uni-Q design was adopted. The manual doesn't refer to ferro anywhere, ferro and Uni-Q seem to be mutually exclusive. 

If the tweeter did lose any fluid, fragments would have certainly ended up across the room by now. I bought these used as demo stock and have been very faithful to the sound, better amps and more importantly better sources (=lower noise) is noticeable.

For the future, looking for used Blades or Sony SS-AR1, for the time being though  the 205/2 will be great companions.

It changes the physical parameters of the tweeter (electrical) so they will sound different.

On 2/14/2024 at 6:43 PM, One and a half said:

For a few weeks now, since the arrival of dreadful humidity, the sound out of the speakers, especially at high voume is sounding very ordinary.

 

- Wooly bass

- Mids, hardly present

- Treble has lost definition

- Image suffers, especially beyond the left and right boundary

 

Thoughts turned to pre-amplification, was the power amp driven enough, lost control somehow? Maybe with the humidity, the speaker drivers are covered with moisture. Umm, these drivers are plastic, and a fibre, so no liquid cleaning there, just dusting off.

 

Well.

 

The mid on the KEF 205/2 has the tweeter as a centre piece, and this was coated with fibres/dust. Brushed this off with a make-up brush, it's super soft and removed all the rubbish. Ports could do with a wring out with microfibre cloth. Done. The rubber was still in good condition, for a speaker 10 years old is good to see.

 

The drivers are mounted with M4 (mid/Tweeter) and M5 cap screws (two woofers), these are usually metal threads, let's see if they are tight. Oh dear, there was a full two and a half turns to make the screws snug on all drivers. It felt like the screws are pulling on a metal ring or structure, not wood, thank goodness.  Was a bit late at night to wake up the neighbourhood,  left the amp running on Tuner at very low volume, just for the exercise.. Today, the sound emanating from the speakers is:

 

- Bass tight, McCartney's bass on Mrs. Vandebilt is very tight, wooliness is gone

- Mids/Vocals clear as a bell

- Imaging back, nice front to back, height dependant on recording

- None of that honking any more

 

It would appear the speakers not tight in the enclosure were moving about creating extra vibrations whatever they wanted to do.  Pure friction held them in place.

 

If you have speakers even 5 years old, worthwhile the check the mounting screws, very little work to tighten these, the bonus of a great sounding speaker like when it was first delivered and cost $0 for the 'upgrade' !

<snip>

Good work!

A friend who was a gunsmith for a local pistol club told me that 90% of the repairs he did were "clean, tighten, oil"— just a need for basic care and service.

Maybe some Loctite on the screws to keep them from loosening again ?

Please remember to look after your ears. Talk to your doctor about an ear cleaning, which can take care of the outside. Changes in weather can change how your ears drain moisture and relieve back-pressure from the middle part behind the eardrum; if you have nasal congestion then you may experience 'congested' sound as well. Very gently 'popping' your ears as you might do on an airplane can make sure the pressure is equalized in front of and behind the eardrum (don't overdo it); this makes a big difference for me.

Secondly, make sure the speaker set up is just right - you can adjust the amount of toe-in to change the high frequency balance of the speaker fairly significantly, and the speakers being too close to walls can close their sound in due to early reflections.

On 2/22/2024 at 3:39 PM, davide256 said:

Maybe some Loctite on the screws to keep them from loosening again ?

I would definitely not do that. Proper screws for a speaker driver will have a metal T-nut that bites into the cabinet. The wood or fiber in the cabinet can compress over time, which I believe is what causes, or at least contributes to, loosening. Also, Loctite is pretty grippy, you don't want to stress the holes in the cabinet from the nuts. Best practice is to tighten annually, but don't be too aggressive with it. If your drivers don't have T-nuts, be very ginger with tightening. Snug is sufficient, wood and fiber strip easily.