I have a pair of Wharfedale speakers, they are only a few years old. Say at a certain volume setting, one tweeter would be 90db at 0m, and the other would be at 87-88db. The measurement technique is far from scientific, but it reflects what I hear. One side is louder than the other and center image is skewed. But other than the volume, I could not detect any distortion or anything wrong with the sound.
I did some troubleshooting and concluded the issue lies with the tweeter and not the crossover or the electronics.
So I assumed the softer tweeter is faulty. My working theory is it uses ferro fluid which dried out. Just a guess, I have no idea what really happens.
So I ordered a replacement tweeter. When it came, it is 2-3 dB softer than the softer tweeter. If compared to the louder one it is 5-6dB difference.
FWIW original tweeter pair has stickers that says "2018 19". The replacement's sticker says "2013 19". Assuming they meant the year of manufacture, it supports the ferro fluid theory. And the replacement tweeter is even worse than my original pair.
But before I jump to conclusion, is there any scenario where the good tweeter is in fact the least sensitive replacement tweeter? And as they age and degrade they somehow become louder?
I did some troubleshooting and concluded the issue lies with the tweeter and not the crossover or the electronics.
So I assumed the softer tweeter is faulty. My working theory is it uses ferro fluid which dried out. Just a guess, I have no idea what really happens.
So I ordered a replacement tweeter. When it came, it is 2-3 dB softer than the softer tweeter. If compared to the louder one it is 5-6dB difference.
FWIW original tweeter pair has stickers that says "2018 19". The replacement's sticker says "2013 19". Assuming they meant the year of manufacture, it supports the ferro fluid theory. And the replacement tweeter is even worse than my original pair.
But before I jump to conclusion, is there any scenario where the good tweeter is in fact the least sensitive replacement tweeter? And as they age and degrade they somehow become louder?
Sometimes, the ferrofluid leaks out, and can slightly change the sensitivity.
Other times, it settles due to gravity to one side of the VC area.
One thing to try is installing the tweeters 180 degrees - upside down, to make the fluid flow back around the VC and balance out.
This may take a while to notice.
Other times, it settles due to gravity to one side of the VC area.
One thing to try is installing the tweeters 180 degrees - upside down, to make the fluid flow back around the VC and balance out.
This may take a while to notice.
Thanks for your input. I would try that.
When you say a change of sensitivity, so it is possible that sensitivity would go up?
When you say a change of sensitivity, so it is possible that sensitivity would go up?
The ferrofluid acts to cool the VC, when it loses fluid, it allows more freedom of the VC, resulting in increased volume.
My experience with some Tonegen tweeters (94L65DS-03HD with an awkward 94 mm faceplate) from the late 1990's is substantially reduced high frequency output and volume with age. These have ferro fluid, and also a doped coating on the dome. I assume that both deteriorate over time. They are on my list to restore (or at least play with), as they were quite common in some high end Australian speakers back in the day, but I ended up sourcing a drop in replacement from Krix.
What testing method?
I might use a mobile phone app such as spectroid. Pop it on a fixed surface, and a tweeter on another. Likely in my case, the edge of the table for the phone, and a chair for the tweeter. Use youtube to find an hour long tone. Then move each tweeter into that same position and measure. Spin a wire out from your speakers to play the tone with the same crossover each time.
That app gives a nice waterfall, so you can see if some other resonance is at play. Not just your tone frequency.
Nothing beats proper gear, but the method is solid.
My HF got thin with age. New fluid took the edge off. Often the fluid sets, but mine dry away and lost contact.
I might use a mobile phone app such as spectroid. Pop it on a fixed surface, and a tweeter on another. Likely in my case, the edge of the table for the phone, and a chair for the tweeter. Use youtube to find an hour long tone. Then move each tweeter into that same position and measure. Spin a wire out from your speakers to play the tone with the same crossover each time.
That app gives a nice waterfall, so you can see if some other resonance is at play. Not just your tone frequency.
Nothing beats proper gear, but the method is solid.
My HF got thin with age. New fluid took the edge off. Often the fluid sets, but mine dry away and lost contact.
But....
How do you explain the OP's statement of "I have a pair of Wharfedale speakers, they are only a few years old."
I am surprised at the short lifespan of the tweeter too. The fact is I have 3 tweeters and they are all audibly different, don't need any instrument to know that. Don't think I will touch another IAG speaker.
There are no electrolytics in the tweeter section. I even measured the film caps just in case (I once encountered a speaker where a film cap is smaller than it should be and thereby reducing the tweeter output). The problem is in the tweeter, the evidence is conclusive.
No matter the why, only solution I see at the moment is to to replace the tweeter.
I have not done any tweeter surgery before. Can you just use any ferro fluid?
There are no electrolytics in the tweeter section. I even measured the film caps just in case (I once encountered a speaker where a film cap is smaller than it should be and thereby reducing the tweeter output). The problem is in the tweeter, the evidence is conclusive.
No matter the why, only solution I see at the moment is to to replace the tweeter.
I have not done any tweeter surgery before. Can you just use any ferro fluid?
This link may prove useful: https://speakerrepairshop.nl/en/instructions/replace-ferrofluid-in-tweeter/c-36
This is the stuff to use: https://willys-hifi.com/products/ferrofluid-refill-kit#:~:text=Ferrofluid is a cooling / damping compound used,with age, gradually reducing tweeter output to zero.
Do not use the cheap stuff used for school science projects.
I'd be interested in knowing which model of Wharfedale speakers you have, in order to possibly find out more about the tweeters.
Here's a link for those not familiar with these retro-look speakers:
https://www.wharfedale.co.uk/denton-80/
Seems to me, at the hugely inflated (rediculous) PRICE those little speakers are selling for, and Mr Navyblue saying he's not had them long, I should think that Wharfdale would be responsible in covering their own product cost-free.
Even Radio Shack warrented their speakers 5 years.
And while I'm on it, if the replacement speakers are not accurately identical, are these now made (mass produced) in china?
I can understand tolerences, but the jacked-up price?
Even Radio Shack warrented their speakers 5 years.
And while I'm on it, if the replacement speakers are not accurately identical, are these now made (mass produced) in china?
I can understand tolerences, but the jacked-up price?