GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Audio Discussions
In the Thread: Constructing LF modules to the limits

Post Subject: The blind contribution of driver suspension.Posted by Romy the Cat on: 9/25/2011

Petar, wonderful observation as usual. I would like to add one factor that is always there but practically impossible to consider predictably.

Any driver has suspension (with exception of suspension-less drivers that are not suitable for bass) and the properness of driver reflecting of what the signal goes is very proportional to the driver excursion. When cone moves from 10% to 70% of it max excursion then it is experiencing the resistance of suspension let say 7 times stronger. The suspension resistance is not the force the is informed about the signal and it behaves purely mechanical, reacting only upon the driver excursion. So, with any driver, regarding of design the excursion means higher introduction of signal not related anomalies. With use of multiple divers we accomplish exactly that – we spread the excursion of one large woofer to the let say 4 mini excursions of small woofers, minimizing the total participation of suspension in the entire ceremony. We spread not only excursion but also flux modulations, thermal compression of VC and many other factors that are much less at low excursion of the small drivers. BTW, we play the same game with horns, where we by adding horns to get more acoustic pressure allow themselves to use the drivers with fewer excursions.

For sure the blind contribution of the driver suspension in 10” driver and 20” are VERY different. And it is possible that 20” driver ay 80% excursion will experience less stress from suspension then 10” driver at 20” suspension. I say “possible” because there is no way to evaluate it properly as no one makes identical 10” and 20” drivers. If someone would make 10” drivers with excursions, suspension and magnetic system of 20” driver then use of multiple 10” drivers would be no brainer and it would 100% preferable then to use one 20” driver. Of cause it is never the case and in real world to predict how different drivers behave is very hard it is all about the specific driver construction.

Now about the tone. Petar, you use 60Hz first order and of cause the tonal concepts are important to you. In your estimation would you feel the same if you use 20Hz and 4^th order? I did listen my ULF sections without the rest of Macondo, trying to get a sense if “tone” is something the I was able to hear in there. I did not recognize that there was anything in there that might have a tone. I did heard the dynamic compression but not tone per say. Can you put 20Hz and 4^th order on your driver and share what you hear?

Rgs, The Cat

Rerurn to Romy the Cat's Site