I purchased a pair of blue heron's on Agon with the tweeter problem disclosed. They sounded exactly as you describe with a lack of high frequency dynamics or general loss of volume. I previously owned a pair of heron i's and was able to easily identify this difference through comparison. My solution was to replace the tweeters with Scan Speak ring radiators. This process is involved but excellent results can be attained. You'll see that scan speak tweeters were used in the BH2's. First you will need to chose the Scan Speak model that has a similar diameter to the HD3P you will likely need to expand the tweeter opening in the box a few millimeters. Next you will need to get into the crossover which can be easily accessed through removing the bottom plate. You will notice that it is a 1st order crossover and thus relatively simple. Next you will need to calculate the resistors needed to properly adjust the sensitivity in the new tweeter. I started with the Sensitivity of the HD3P and its current resistor/s to find the existing final sensitivity. Then built an resistor network around the scan speak to result in the same final sensitivity. Additionally, the HP3P makes use of a transformer which will need to be removed. Another option is to use a L-pad which is basically a variable resistor that you can dial in to your liking(Would require more box surgery and would likely be sonically inferior). Hope this helps it worked our very well in my system.
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Hi Michael, Your info on the HD3P replacement is very helpful. I have Meadowlark BH's with that now-deflated tweeter. How were you able to remove the HD3P's? I removed the screws, tried to wedge them out, put a hair dryer on to melt the gasket and nothing. Won't budge, turn or anything. Is there a special tool or didn't you have this problem? Any thoughts or suggestions wold be appreciated. Thanks, David |
DDrave44 Try the large screw in a small hole trick. Basically you remove the original screws then put a single wide threaded screw that is just a bit too large for the original hole. VERY CAREFULLY hand thread it into the tweeters plastic flange ( where the hole is ) and once it is tight ( not screwed into the baffle but tight in the plastic) you use a claw hammer's claw end to slowly pry up on the head of the screw. Put a cloth under the hammer head to prevent damage to the baffle. I have done this on several BHs and even a few BH centers. Slow and steady pressure will release the tweeter from the keldamp gasket material. Just be super careful not to puncture the outer mylar membrane. Good luck with your BHs. Mike |
Edward, The only repair data I have is from the thread above: My two HD3Ps are currently being modified repaired at Moca Audio (www.moca-audio.com) in Tours, France by an acoustical engineer (Marc-Olivier Chauveau) who specializes in Audax drivers. I suggest contacting Mssr. Chauveau and asking if he still does the service to the HD3Ps. I have a singe un used HD3P left in stock. It has deflated even never having been used. |
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