Tectonic Elements TEBM46C20N-4B BMR 3" Full Range

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#6
I have a tale to tell about these drivers...

I ordered a pair about 12-18 months back and measured them. Wow, they looked great! Low distortion, and smooth on and off axis response up to 16kHz with some ragged extension a bit higher. I bought a bunch more thinking these would replace my previous go-to fullranger, the TangBand W2-800SL (IMO a great driver).

So fast-forward to about a month or two ago. After taking a long hiatus I finally start building a project and go to remeasure the BMRs only to find some rather significant changes in the response. The upper end is now rolling off earlier, around 12-14kHz. And there is a 10dB deep dip around 9kHz that wasn't there before. WTF? I start checking my equipment, measuring setup, amp, etc. and remeasure 6 of the 8 drivers I have in hand. They are all showing almost identical signs of some kind of frequency response changes.

I contacted Tectonic and told them what happened. A few days later I got a reply from a secretary type who said she would forward my message to the QC/Tech department and they would get back to me. They never did. So now I have a gaggle of these that I can't use.

My guess is that the adhesive in the cardboard honeycomb diaphragm is aging. The drivers were stored in my garage, which is neither actively heated nor cooled and I live in CA and it can get hot in the summer in there, although probably not typically over 90F. At first I was very excited about Tectonic's BMRs but now they are in my "AVOID" category, especially since I heard from another well known DIYer about some other problems with their products and lack of support from the company. YMMV.
 
#7
CharlieLaub said:
I have a tale to tell about these drivers...

I ordered a pair about 12-18 months back and measured them. Wow, they looked great! Low distortion, and smooth on and off axis response up to 16kHz with some ragged extension a bit higher. I bought a bunch more thinking these would replace my previous go-to fullranger, the TangBand W2-800SL (IMO a great driver).

So fast-forward to about a month or two ago. After taking a long hiatus I finally start building a project and go to remeasure the BMRs only to find some rather significant changes in the response. The upper end is now rolling off earlier, around 12-14kHz. And there is a 10dB deep dip around 9kHz that wasn't there before. WTF? I start checking my equipment, measuring setup, amp, etc. and remeasure 6 of the 8 drivers I have in hand. They are all showing almost identical signs of some kind of frequency response changes.

I contacted Tectonic and told them what happened. A few days later I got a reply from a secretary type who said she would forward my message to the QC/Tech department and they would get back to me. They never did. So now I have a gaggle of these that I can't use.

My guess is that the adhesive in the cardboard honeycomb diaphragm is aging. The drivers were stored in my garage, which is neither actively heated nor cooled and I live in CA and it can get hot in the summer in there, although probably not typically over 90F. At first I was very excited about Tectonic's BMRs but now they are in my "AVOID" category, especially since I heard from another well known DIYer about some other problems with their products and lack of support from the company. YMMV.
Click to expand...

Suggestion, did you try playing them for at least an hour before testing them?
 
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