I thought I would share this stuff.
I had the pleasure of meeting an ex-JBL Q&A person who worked at the So Cal plant almost from the beginning. He mentions that JBL specs were +-3dB over the specified frequency response or he would reject the driver. This difference was typically not detectable by the human ear but JBL took pride in their specs. It was not unusual for 20% of the drivers to be rejected and sometimes whole batches would be rejected. These drivers were cut-up and destroyed!
He also mentioned that they used to wire speakers directly to a wall outlet, which would generate a 60 Hz tone. The voltage translated to something like 1600 watts! Most woofers would crease the cone or blow out the VC. One of the 15 or 18 inch professional bass drivers survived for three one minute intervals. He then hooked up the driver to his test rig and found that it was within 1 dB of spec which he thought was magnet de-gauss caused by the wall current.
What really caught my attention was speaker distortion. JBL used to test at 1 watt/1meter and they considered 7-8% percent to be quite good for their products. Most speakers generate this amount of distortion, which was a real surprise. Unfortunately, he couldn't tell which driver materials or different technologies like electrostatics were the best because JBL simply wasn't exotic. (The Bose 901 was sort of a standing joke, they had 20% distortion!)
BTW, I asked if he knew Bert Locanthi and he says he can't remember him although he is sure he has met him!
I had the pleasure of meeting an ex-JBL Q&A person who worked at the So Cal plant almost from the beginning. He mentions that JBL specs were +-3dB over the specified frequency response or he would reject the driver. This difference was typically not detectable by the human ear but JBL took pride in their specs. It was not unusual for 20% of the drivers to be rejected and sometimes whole batches would be rejected. These drivers were cut-up and destroyed!
He also mentioned that they used to wire speakers directly to a wall outlet, which would generate a 60 Hz tone. The voltage translated to something like 1600 watts! Most woofers would crease the cone or blow out the VC. One of the 15 or 18 inch professional bass drivers survived for three one minute intervals. He then hooked up the driver to his test rig and found that it was within 1 dB of spec which he thought was magnet de-gauss caused by the wall current.
What really caught my attention was speaker distortion. JBL used to test at 1 watt/1meter and they considered 7-8% percent to be quite good for their products. Most speakers generate this amount of distortion, which was a real surprise. Unfortunately, he couldn't tell which driver materials or different technologies like electrostatics were the best because JBL simply wasn't exotic. (The Bose 901 was sort of a standing joke, they had 20% distortion!)
BTW, I asked if he knew Bert Locanthi and he says he can't remember him although he is sure he has met him!