Posted by Roy on November 16, 2002 at 14:31:59:
In Reply to: Re: Re:A little help needed posted by Duke on November 13, 2002 at 17:04:22:
Success
At the beginning of the week I asked Soundlab for the written instructions to heat treat my panels. Days passed, I sent Soundlab two reminders, Duke telephoned them for me, finally out of frustration I telephoned Brad on Friday to get verbal instructions, then on Saturday morning there was an email for me from Roger, the written instruction had arrived. I can imagine that this two page document took few days to prepare as the intructions are very thorough and well written, definitely essential reading prior to getting out your heat gun. I am sure that some of you have done this before but you don’t get second chances doing this, I can imagine that a few holes have been burnt through panels in the past, your heart is in your mouth when you start. In my case the membrane was too tight so there are no visual signs to show that you have heated the membrane up to the critical temperature that allows it to assume the correct tension. I had to do the procedure about 8 times on the first panel, increasing the temperature and moving the heat gun more slowly each time I did it. I am fortunate to have a Real Time Analiser so after each pass over the complete panel I tested the response. At first there was no change then the base response slowly improved, first by 1dB then a couple of dB, finally the response improved by at least 10dB on the last pass. The second panel took two passes to get the membrane tension correct. Each pass takes about 5 minutes.
The heat treatment procedure also corrected the lack of high frequency energy in the center of one of the panels when I first received it 10 days ago.
I noticed other benefits after heat treating my panels. They play louder with the same input signal and I am now able to increase the bias from 12 o’clock to 2 o’clock before the crackling starts.
I have recorded RTA curves that show before and after the procedure.
I used standard backplate settings to record the curves so that they would be more relevant to most users. The backplate settings that I use to listen to music are quite a bit different.
May I thank Duke for his efforts in helping me get a quick solution to this problem
