I just got a pair of Duntech Crown Prince speakers and they're flat out amazing. However, when pushed, I hear the woofers splatting/bottoming out unlike any other speakers I own. I'm definitely NOT over pushing them.
They were recently professionally refoamed with Dynaudio foam but I think they messed up the voice coils or something.
Any remedies or thoughts?
I really need a whole woofer recone kit.
Duntech has been very slow to respond and I'm not sure they can even help.
They were recently professionally refoamed with Dynaudio foam but I think they messed up the voice coils or something.
Any remedies or thoughts?
I really need a whole woofer recone kit.
Duntech has been very slow to respond and I'm not sure they can even help.
There used to be a service Dynaudio factory provided to repair drive units for a large fee and you would send them the faulty ones. Recently I have designed a 3 way with a Morel MW 265, and this unit performs very much like 24w75 well suited to a sealed enclosure. They are both 220cm2.
Are you saying the Morel driver is a worthy replacement? Almost as good? Just as good? Will it even fit or is that another gamble?
Morel mw 265 is the closest replacement driver that I know of. There is a small difference in sensitivity of 1 dB in favor of Dynaudio and the Qts of Morel is slightly lower. Those are based on their datasheet which are old by now. I cosider them to be acceptable. Another difference is the frame diameter, Morel measuring 222mm, Dynaudio 238mm. The mounting holes diameter is 214mm (Morel) and 220mm (Dynaudio). This needs to be taken into account.
Long time ago, Dynaudio and Morel founders used to work together, hence the similarity of products, then they went apart.
Long time ago, Dynaudio and Morel founders used to work together, hence the similarity of products, then they went apart.
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There is another option worth taking into consideration, imo. Dynaudio MW 182, the same size class of a woofer as 24W75 and MW265, even though MW182 is specified as Sd=235cm2, because of a different measuring convention. It is a 4 ohm with not that low of Re=3.7. This is a unit with stiffer surround and because of it higher Fs and lower Vas, well suited to a sealed cabinet as well, has a larger voice coil (4"). The good news is the mounting holes are the same as original unit. On account of voice coil being nominally 4 ohm the crossover frequency could change a little and the total impedance would also drop making it a little heavier to the amp. This unit is very much a candidate that would not bottom out.
I have got a version of it (Re=3.1; 3" voice coil) specifically manufactured for Volvo automobiles that I managed to acquire second hand while they were still around. I keep these as spares for my 24W75's.
Can you work out a crossover schematic of Duntech Crown Prince and how the drivers are wired between themselves?
I have got a version of it (Re=3.1; 3" voice coil) specifically manufactured for Volvo automobiles that I managed to acquire second hand while they were still around. I keep these as spares for my 24W75's.
Can you work out a crossover schematic of Duntech Crown Prince and how the drivers are wired between themselves?
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I also have a pair of Duntech Crown Price and was lucky to get one of the last sets of new drivers from Duntech here in Sydney. Duntech have been sold out of replacement drivers for a long time now.
Personally, I'd pull the drivers and test them individually. Then just send back whatever is faulty to Dynaudio for exchange.
Personally, I'd pull the drivers and test them individually. Then just send back whatever is faulty to Dynaudio for exchange.
The problem is sending them back for exchange for what? This driver isn't made any more and my understanding is nothing is similar to it without altering the sound of the speakers.
Did I just waste my time writing 3 posts on topic?
why do you think that? Those are valid options if the OP isn't able to get his original drivers repaired or get exact replacements, both of which I'd consider to be the ideal solutions, with any non-exact replacement drivers being a 2nd best option.
To the OP, other than them apparently being more compliant than you recall, is there any other actual problem? If it sounds ok and functions ok, maybe there's nothing to worry about? if you push the woofers in easily, do you hear a scraping sound that indicates that the voice coils are rubbing, or are you just concerned because it's bottoming out easier than you think it should?
If it seems like the voice coils are rubbing, then this should be able to be remedied by having the drivers re-foamed, perhaps this time by somebody who is more experienced. Quite often people will re-foam without removing the dust cap and shimming the voice coil to center it. Many prefer this method because it eliminates the need to remove and replace the dust cap, but it does add risk that the voice coil may not end up perfectly aligned. In the case of dynaudio drivers that have a very unique dust cap, I can understand why somebody would prefer to refoam without removing them, as I doubt exact replacements are available, so it's important that the person refoaming them is careful to ensure that the voice coil is aligned as the glue sets up.
Yes, the dustcap and cone are actually one piece! There are tiny holes where the cone and cap meet which are used to center the coil by the use of pieces of steel wire. When the glue is set the wires are pulled and the tiny holes are sealed. It is therefore not that easy to center those drivers properly.
Regards
Charles
Did I just waste my time writing 3 posts on topic?
Excellent posts thank you. I actually didn't see one you mentioned. I'm not sure how I could get around the holes not lining up or he large hole being too large (sure i can drill new holes but gosh I don't want to do that).
Anyway, looks like the Morel might be a worthy replacement but I certainly want to replace with original parts if possible.
I spoke with Bill at Millersound (great guy btw) and he said these were refoamed incorrectly or something. He said something about the shims and how they should have realigned the voice coil and something "gummed" up.. This is above my head but sounds like he really knows what he's talking about.
He said he could fix them but recommended i take them somewhere local in DFW and any competent speaker repair shop should be able to fix this.
He said he could fix them but recommended i take them somewhere local in DFW and any competent speaker repair shop should be able to fix this.
Well yes they're bottoming out much easier than they should. I've had a lots of speakers in here from Klipschorns, Tekton Double Impacts, Wilson Watt Puppy 5.1, Thiel, KEF Reference 5 etc... NONE of them came close to bottoming out on these tracks.
I'm not talking only about Flight of the Cosmic Hippo or I Love Bass tracks. If I were doing something totally stupid I would certainly know.
I feel double strongly about this after Bill at Millersound said "yep, I've seen this with at least half of those woofers that were refoamed". So apparently this is expected when they were refoamed incorrectly.
Manufacturer should be able to answer you what (T/S parameters) should your new replacement unit measure like. If this Duntech employed Dynaudio unit were standard 24W75, then everything is clear, they should provide you replacements of such specs, even better if you asked them to use rubber, instead of foam which is a fault just waiting to happen again.
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I wonder what's the designation of your woofers. Can you pull one out for inspection?
I'd like to repeat my request from post #6, a couple of shots from x/o board should suffice my curiosity.
I'd like to repeat my request from post #6, a couple of shots from x/o board should suffice my curiosity.
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Here are some pics of the woofer. It's the 24W75 XL 8ohm. No: 87385
Here's what Millersound said about it.. Not totally sure I understand what this email is saying but you guys might understand it more:
"Dust cap is non-removable. Easy to tell the problem:
Rear air filter gummed-up from remnants of the rear air filter. Gap must be cleaned and a non-rotting filter must be installed. Must be taken completely disassembled,
including (of course) the spider suspension. Refoamed again too.
This was absolutely not a “pro” job, but they didn’t make a cosmetic mess, and therefor I’d make an exception and service it. Cost with return UPS/insured is $137.00
Payment is only by check or m/o to Millersound, in carton, along with copy of this email. Include clearly-indicated return-shipping address.
Your problem all makes sense now!"
Here's what Millersound said about it.. Not totally sure I understand what this email is saying but you guys might understand it more:
"Dust cap is non-removable. Easy to tell the problem:
Rear air filter gummed-up from remnants of the rear air filter. Gap must be cleaned and a non-rotting filter must be installed. Must be taken completely disassembled,
including (of course) the spider suspension. Refoamed again too.
This was absolutely not a “pro” job, but they didn’t make a cosmetic mess, and therefor I’d make an exception and service it. Cost with return UPS/insured is $137.00
Payment is only by check or m/o to Millersound, in carton, along with copy of this email. Include clearly-indicated return-shipping address.
Your problem all makes sense now!"
Attachments
Have you spoken to Dynaudio? When I contacted them about a failed tweeter they were able to provide me a remanufactured one on an exchange basis. ie. You send back your old ones and they send you a repaired item to original spec (for a cost). They then repair your failed driver back to original spec for the next person. Very common practice in a lot of industries.