It would be wise to have the Wharfedales serviced and the parameters measured before building enclosures.Specifically the coil needs a coating to prevent the wire unwrapping as the original cellulose ages.The roll surround hardens and requires treatment to soften it and an application of a sealant to prevent air leakage.The resonant freq,for this model can be as low as 25Hz,although 35Hz is a typical figure.A vented box with an internal volume of 80 L tuned to 40Hz is ,the smallest size that I would recommend for this speaker.
Thank for your reply,
one of the speakers is bard new , unused and it sound just perfect, sadly the other one has been used for several years, and i found it to sound not as good as the other one, not as loud and it somehow lack the high freq. overall sound a bit flat. Dont know if this could cause it but that driver have tiny hole in dust cap, and the foam around smalled cone as perished.
I have build 100L volume vented enclousure as you sugested.
one of the speakers is bard new , unused and it sound just perfect, sadly the other one has been used for several years, and i found it to sound not as good as the other one, not as loud and it somehow lack the high freq. overall sound a bit flat. Dont know if this could cause it but that driver have tiny hole in dust cap, and the foam around smalled cone as perished.
I have build 100L volume vented enclousure as you sugested.
DonLuka:
Wow - you don't waste any time! I was going to suggest exploring a back-loaded horn cabinet design for these. So, how do they sound in your vented enclosures? I have some Super 8 RS/DDs that WILL go into horn cabinets some day. I think the relatively powerful motor on these should suit a horn design. It will be interesting to model some of the classic designs vs. modern ones. Maybe you could build some too, and compare them with the vented box performance. We await your report...
Sorry to hear of the problem with your one driver. Lets see... does it have a ferrite or alnico magnet? I've come across weakened alnico magnets; never ferrite. I doubt that a tiny hole in the dust cap would make an audible difference as you've described. Maybe some crud in the gap? Not that it would have been used in your speakers, but I've found dried-up ferro-fluid to cause reduced output. Or, as VaNarn suggested, perhaps the coil windings have come unglued? I did have that happen on a tweeter once, with exactly those results (reduced output). Sadly, re-gluing the windings didn't completely restore it's performance. One hint I can give you: Tempting as it may be, DO NOT undo the 3 screws on the back of the motor assembly. Yes, it will allow you to pry off the magnet and inspect the coil, but putting it back on and re-centring the pole piece without completely destroying the voice coil is - in my experience (!) - nearly impossible.
So, VaNarn: How then should we go about accessing the coil to inspect and re-coat it? The only way I can see is to dissolve the adhesive at the dust cap, surround and spider with a solvent. Is that the service procedure you are recommending? Can you provide any further details as to the materials to be used to treat the coil and surround? Thanks very much!
Wilf
Wow - you don't waste any time! I was going to suggest exploring a back-loaded horn cabinet design for these. So, how do they sound in your vented enclosures? I have some Super 8 RS/DDs that WILL go into horn cabinets some day. I think the relatively powerful motor on these should suit a horn design. It will be interesting to model some of the classic designs vs. modern ones. Maybe you could build some too, and compare them with the vented box performance. We await your report...
Sorry to hear of the problem with your one driver. Lets see... does it have a ferrite or alnico magnet? I've come across weakened alnico magnets; never ferrite. I doubt that a tiny hole in the dust cap would make an audible difference as you've described. Maybe some crud in the gap? Not that it would have been used in your speakers, but I've found dried-up ferro-fluid to cause reduced output. Or, as VaNarn suggested, perhaps the coil windings have come unglued? I did have that happen on a tweeter once, with exactly those results (reduced output). Sadly, re-gluing the windings didn't completely restore it's performance. One hint I can give you: Tempting as it may be, DO NOT undo the 3 screws on the back of the motor assembly. Yes, it will allow you to pry off the magnet and inspect the coil, but putting it back on and re-centring the pole piece without completely destroying the voice coil is - in my experience (!) - nearly impossible.
So, VaNarn: How then should we go about accessing the coil to inspect and re-coat it? The only way I can see is to dissolve the adhesive at the dust cap, surround and spider with a solvent. Is that the service procedure you are recommending? Can you provide any further details as to the materials to be used to treat the coil and surround? Thanks very much!
Wilf
Hi,
Thank for your advice , before i posted here I was thinking of some other boxes for them ( modified voigt pipes or something else. However they do sound pretty impressive in vented boxes. about drivers , I spotted the problem it wasn't drivers fault... actually my Amp is going off on one channel, and that's why one of the drivers sounded weaker than the other. I also bought KEF T15 tweeters , do you think its a good idea to set them with those Whafedale's ?.
Regards
The best solvent for removal of the cone assembly (cloth roll surround,corrugated spider and the green felt) is acetone.Several applications are usually are needed to soften the old contact cement.It is best not to apply the acetone to the aluminium dome as the paint will dissolve.The magnet for this model has always been a ceramic type(1.4T).I used model aeroplane dope as the coating material,but this is a rare item these days(cellulose nitrate) and I think that a shock resistant super glue may be a better alternative for this application.The D.C. resistance of the aluminium wire coil should be around 10 Ohm.The connections of the voice coil to the pigtail leads should be remade using an aluminium solder and sealing the remade joins from the atmosphere is advised.The roll surround can be softened by rolling it section by section with your fingers in a back and forth action.The aluminium dome can be smoothed if dented and checked that it is firmly glued to the tweeter cone.I prefer to remove it and fit a dome at the junction of the coil former and the the cone.A foam pad attached to the centre pole piece is an improvement which can be made at this stage as it nullifies a cavity resonance.When re-fitting the cone it is useful to reduce the roll surround to a shallower profile as the semi circle shape of the original is not the best profile for a linear action.To seal the surround use "Polymark" dimensional fabric and craft paint pen ;shiny black No. PM 101. I have found back loaded horns to be excessively coloured for my tastes although people seem to adapt to them despite the audible shortcomings.That it not to say the Golden 10 RS DD is ideal for reflex loading as unless the resonance is dropped to 25 Hz, the Qts can be on the high side of what is preferred.
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