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JohnG 23rd April 2017 12:29 PM

HD-3P refill with air.
I recently purchased a pair of speakers using the KLS3 Audax drivers.
The cabinet has a different design as it has a larger volume and is five sided.
There is also a externally mounted crossover.
The HD-3P Gold Peizo Tweeter had the crinkle surface due to deflation. I was OK with this as I was aware of my alternate choices for a replacement tweeter.
I looked upon the HD-3P as sacrificial, so before I went forward and investigated the full requirements to exchange this tweeter. I had a dabble, using some past very basic instruction I had read, I removed a tweeter and started my investigation to identify a inlet for re-inflating the Gold Peizo Dome with air.
I have achieved the intended task and am pleased with the outcome.
I had a few hours listening to the speakers on the eve of my modification attempts, and was very aware of a lacking in the highs and mids.
Following my success at re-inflating, I had another listening session, revisiting the previous days replays. The difference in performance was very much improved to my untrained ears, I could not imagine myself wanting more, I have a speaker that has a very similar expression as my ESL57 when listing to female vocals, the speakers now also project a very listenable mid/high presentation into the room.
I have left a Roadmap of Steps to achieve a air refill on another forum, if anybody would like to be directed to these and read a few follow up comments PM me.

Richard 25th April 2017 11:14 AM

Re: HD-3P refill with air.
Hi John,
Well done :)
Please paste the info here to help our members also.
Many thanks :thumbsup:

Greg. 25th April 2017 02:20 PM

Re: HD-3P refill with air.
The thread is here.

You will see I have posted my reservations on what John is doing based on the experience of others including a friend of mine who is a member here.

If John is getting good results then I wish him all the very best and infact have a pair of duff HD-3P's here which he is welcome to for the price of the postage. PM me John with your address and we can sort something out if you are interested.

Richard 25th April 2017 03:55 PM

Re: HD-3P refill with air.
Thanks John and Greg :thumbsup:

There's also a thread running for 10 years(!!) on diyAudio which gets interesting around post 31 which you've probably both read but I'll link to for anyone else looking for info and ideas,

JohnG 25th April 2017 05:25 PM

Re: HD-3P refill with air.
Thank you four support on the HD-3P re-inflation.
I have to this date not found a set of steps that will give confidence to a individual, who has desire to reinflate the Gold Piezo Diaphragm.
The link supplied by Greg, should if all deflation is of the same cause, allow a individual to re-inflate their HD-3P Diaphragm.
I have experienced after a simple procedure, a replay to be enjoyed.
I can not vouch if the end product matches the original factory set up, but it will be usable and be capable of offering a performance that satisfies.
After pondering some of the earlier responses a I received to my posts, I asked myself, how many drive units, after years of service are a match to the original
Factory set up. In my mind I think not many, UV deterioration on foam surrounds, voice coils slowly deteriorating.Electro static films degrading.
Speakers containing these type of deteriorating drive units are still valued for their performance by their owners. If a renovation take place, where is the assurity they are now performing to the original factory setting.
A difference in a performance for the better may be heard that offers a enthused enjoyment and a renewed pride of ownership may be instilled. I,ll settle for that.

bob orbell 25th April 2017 07:35 PM

Re: HD-3P refill with air.
Only time will tell if your repair is effective, air is made of very small parts and I think that Pre 65 might be correct with his comment, any way, best of luck. BOB

JohnG 26th April 2017 06:42 AM

Re: HD-3P refill with air.
The idea the leakage issue is now corrected and no longer a problem is not being proposed. A set of easy to follow steps to re inflate the diaphragm is the instruction on offer.
I am however on the way to producing a secondary attachment that will allow a refill maintenance with a very easy to access fill point. The correct type of non return valve is being sought.

Greg. 26th April 2017 09:58 AM

Re: HD-3P refill with air.
Yes, John, that seems to me the only way to make it a simple procedure that can be done in seconds without disturbing the tweeters mounting in the baffle. I believe that is what Moca Audio did with their fix. The trouble is, no doubt the seal or porosity of the diaphragm will continue to degenerate.

Don't overlook my offer of my duff tweeters which you are welcome to.

Greg. 1st May 2017 07:59 AM

Re: HD-3P refill with air.
John, you have a PM.

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