Normal
Re: 60 Degree DIY Mid Hi[ATTACH]154550[/ATTACH]If you like. In a subwoofer attack and release times of 30 seconds or longer wouldn't be un-warranted, but that requires a lot of envelope tracking so the 5-10 seconds that most limiters allow gets the job done and sounds OK. I've attached a capture of the LSI power test data from one of our 18" woofers, as you can see it takes about 7 minutes for the coil to come to temperature - by which time it's about doubled in impedance (i.e. is now effectively 16Ω instead of 8Ω). This is with AES rated power input, which should be a long-term survivable power level if excursion is kept under control.All that says nothing about mechanical constraints, these power tests are in free air. Add a cabinet and the limits of the woofer will not be the same. A basic thermal limiter will save your bacon in nearly all situations. Unfortunately, excursion cannot be limited with a simple peak limiter: your best bet is to use an appropriate high pass filter (e.g. 2nd order at the box tuning frequency for a normal direct radiator). In a reasonably designed box, between the thermal limiter and the high pass filter, it ought to be pretty difficult to exceed the capabilities of the woofer. More importantly, with such a system the first indication of distress will likely be given by the woofer so an experienced operator will know where the limit lies. Klippel have done some significant research recently into a method for reliably limiting excursion, primarily for small devices, but I have not yet seen a pro audio application of it. To my knowledge there is no widespread tool that will limit excursion directly.
Re: 60 Degree DIY Mid Hi
[ATTACH]154550[/ATTACH]If you like. In a subwoofer attack and release times of 30 seconds or longer wouldn't be un-warranted, but that requires a lot of envelope tracking so the 5-10 seconds that most limiters allow gets the job done and sounds OK. I've attached a capture of the LSI power test data from one of our 18" woofers, as you can see it takes about 7 minutes for the coil to come to temperature - by which time it's about doubled in impedance (i.e. is now effectively 16Ω instead of 8Ω). This is with AES rated power input, which should be a long-term survivable power level if excursion is kept under control.
All that says nothing about mechanical constraints, these power tests are in free air. Add a cabinet and the limits of the woofer will not be the same. A basic thermal limiter will save your bacon in nearly all situations. Unfortunately, excursion cannot be limited with a simple peak limiter: your best bet is to use an appropriate high pass filter (e.g. 2nd order at the box tuning frequency for a normal direct radiator). In a reasonably designed box, between the thermal limiter and the high pass filter, it ought to be pretty difficult to exceed the capabilities of the woofer. More importantly, with such a system the first indication of distress will likely be given by the woofer so an experienced operator will know where the limit lies. Klippel have done some significant research recently into a method for reliably limiting excursion, primarily for small devices, but I have not yet seen a pro audio application of it. To my knowledge there is no widespread tool that will limit excursion directly.
