I have a pair of old Dynaudio 17W75 woofers that had been in storage for many years. I just pulled them out of their enclosures and tested them. Qts has changed quite a bit and I assume that is due to hardening of the surround. Original Qts was 0.70. Do any of you know if replacing the surrounds is possible and economically viable?
You could try some Rubber Renue or some other rubber rejuvenator on the surrounds, and see if that softens them up a bit. Kinda sounds like you should just replace the drivers with something new.
jeff
jeff
Economical cause their price and raririty. A foam surround could be tempting.
How looks the surrounds ? Do you see cracking surface or feel stifness with fingers ?
The spider alas can be a collateral suspect.
How looks the surrounds ? Do you see cracking surface or feel stifness with fingers ?
The spider alas can be a collateral suspect.
The rubber surround feels a bit stiff but I don’t really have something to compare it to. There are no cracks in the rubber. fs has increased. It is about 80 Hz now.
I am going to try that. I am setting up a test bench to check out some Soundstream car audio amplifiers that were Nelson Pass designs that have also been sitting in storage for a long time. I can use the Dynaudio drivers as loads and run them at a low power setting for a long period of time. Not sure if I should do this with steady state tones or actual music signals.
Perhaps you could use that unit without making anything about their surround. What is the intended driver configuration?
I am thinking of using them as a midbass driver in a 4 way design. Over 10 years ago, the original design engineer for How Hear This (NHT) M3.3 was selling new old stock drivers on diyAudio after Recoton bought NHT. Recoton was just going to throw them out. I have several boxes of 10” drivers used in subwoofer designs by NHT that have the same motor as the famous 1259 12” driver from that era. I would cross a pair of the 10” to the Dynaudio if they prove to be usable. The original NHT design used a 6” driver made by Fostex in a sealed sub-enclosure. I have attached a pdf that I copied from a diyAudio member’s web site that may or may not still be active. His article is the motivation for what I want to do. I am thinking of using a DSP to implement the crossovers instead of the inductor and capacitor crossover design in the attached article. I also bought a box of the SEAS 4” midranges used in that design back then. Don’t know what tweeter I will use yet. I have one new in box Dynaudio D28-AF and two very used ones that need new domes.
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You will need to run the crap out of them for awhile. I like to use a mixed tone, like 40-50Hz and 100-120Hz. Need to exercise the stiff surround and spider. Just run it up until you can hear some distortion, back it off a bit and let 'er rip for several hours.
Dan
Dan
Yes & Yes. I replaced the surrounds on my 35 yr old Vifa midwoofers since they suffered from the same issue. You can find tutorials on Youtube. It is not that diffucult. Get the correct surround and glue.
Alright, you can high pass them appropriately and need not worry about surround.
Exchanging surrounds would make sense if you were to expect lower bass
as in a 2 way speaker. Not your case anyway.
I'd measure all T/S parameters for the sake of it, which is usual practice when you build.
