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-   -   Dynaudio D52AF / D28AF lack detail? (http://www.diyaudio.com/forums/full-range/217705-dynaudio-d52af-d28af-lack-detail.html)

pshdk 10th August 2012 08:08 PM

Dynaudio D52AF / D28AF lack detail?
 
Hi,
I've just purchased a pair of Dynaudio speakers mps330. 20 years old. The 4 bass drivers have been replaced not to long ago.
They lack detail and life. It's sometimes hard to hear what being sung. It sound like a blanket is covering the speakers.
Could there be something wrong? or is this the sound to expect from the Dynaudio D52AF / D28AF?
Thanks,
Paul

s3tup 11th August 2012 10:47 PM

Look at crossovers too...

Jay 12th August 2012 01:23 AM

The tweeter is good. Anyhow, wrong crossover can make any good 2 drivers to sound muddy. If you change the woofer or tweeter to a different ones, that will surely happen. Are you sure you replaced the bass drivers with the same type? (They are hard to get!).

Then, are you sure the tweeters have not been rewound with new coil after fried during its long 20 years of life? (If you bought second hand speaker, it is important to check this)

bear 12th August 2012 04:25 AM

Are you sure the mids and tweets are working??

Then are they are the proper level?
IF the woofers that were used to replace are substantially higher in sensitivity than the originals, there may be a major difference in level between the woofs and the rest...

You should investigate.

A bit of FFT software and a random mic will give you the relative levels between the drivers... take a reading on axis to the mids at about 2-3ft out to see the relationships between all the drivers... i won't be exact or perfect but it may show what is wrong rather quickly...

_-_-bear

PS. it is ok to disconnect the drivers and run the woofers alon, the mids alone and the tweeters alone to see if they are running properly...

pshdk 12th August 2012 10:31 AM

I Will disconnect the drivers like you said and listen. The 4x woofers were replaced by Dynaudio but not with the original, I have the receipt from previous owner.
How would I know if the coils have been rewound?
Thanks for the advise.

pshdk 12th August 2012 11:05 AM

I disconnected the drivers and the midrange sounds a bit like a tweeter. It sounds like a speaker playing when you hold it in your hand, if that makes any sense. I get distortion at low to middle volume and find it hard to hear whats being sung and becomes very harsh.

s3tup 12th August 2012 11:13 AM

Maybe the voice coil got stuck - magnet bay become unglued... If you can _carefully_ try to move the diaphragm by touching just the point where the voicecoil connects to the dome, kinda... move it for 1mm or less, just to feel whether it is stuck, rubs, or everything is okay.

Then the voice coil may be disconnected from the dome...

Just don't run too much volume thru it.


And if the tweeter with the xover connected sounds like a midrange.... maybe they swapped mid/tweet xover wires :)

Or maybe the midrange xover capacitors died... one of them... conect the woofer in place of midrange and check whether you hear something meaningful.

Oh, and it's not reccomended to run the xover with drivers disconnected, occassionly it could short the amplifier's output thru resonances in 2nd order xover... You may put some 4-10 ohm resistors in place of drivers

Jay 12th August 2012 12:48 PM

Quote:

Originally Posted by pshdk (Post 3123516)
How would I know if the coils have been rewound?

For tweeters, usually the coil is not rewound but replaced. If only one replaced it is easy to notice physically (or from comparing the sound if cannot access the inside). If both have been replaced it is not easy (needs experience in seeing good build of good tweeters).

The Dynaudio is quite airy and can accept a bit of power. You should be able to use a single capacitor in series and observe a good and clear sound

pshdk 12th August 2012 01:12 PM

I think that i'm quick to doubt myself when listening to speakers because I don't have experience. The vocals are more clear from the woofers, so it looks like the mid drivers are defect. Maybe a clue was that the 4 bass drivers have been replaced? I think the only option fro me now is to have a professional look at them. :( Perhaps there is an upgrade that would not cost to much money while i'm at it?
Thanks again!

Jay 12th August 2012 01:34 PM

Quote:

Originally Posted by pshdk (Post 3123635)
Maybe a clue was that the 4 bass drivers have been replaced?

If individual drivers are okay and the muddy sound came from improper/unsuitable crossover (changing the woofers makes the crossover unsuitable), you can test it by removing the woofers. If the sound still unclear without the woofers, then the issue is somewhere else.


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