Very Confused about sat/sub systems (1 Viewer)

[brian a]

I though I had a handle on the whole sat/sub crossover thing until I read this today on avs:

Anyway, back to the woofers. It happens that I'm in the middle of some sims designing a system with Scanspeak drivers with sorta similar (close enough) specs to the HiVi drivers in the Divas. Now, lots of speakers can be designed to play low using small drivers with skillful box design. But, if you want it low AND loud AND clean the laws of physics say you can't move enough air to get the job done with tiny drivers. So, what do the sims say? Anechoic response (no room gain), with a sealed enclosure, gives you a max of the following before the distortion gets really ugly:

Two 8" drivers: 102dB at 2 meters and 80Hz

Two 5.5" drivers: 94dB at 2 meters and 80Hz

One 6.5" driver: 90dB at 2 meters and 80Hz

So that's saying that with your crossover at 80Hz you need at least 2 8" drivers in your mains. That seems to go against a lot of what I had read. If this is the case, how could you ever justify setting a set of mains to large?

brianca.... (still learning before next speaker upgrade)

 

[brian a]

Anyone have any insight into this? I'm about to upgrade speakers and this will have a huge impact on my purchase. I don't want to lean to heavily on the measurements of what speakers do since it's such a subjective item, but I would like to know if this is even mathmatically true.

My current Energy C-6's seem to be able to make quite a bit of noise without having 8" drivers in them.

I want to get a set of M&K S-150thx speakers and they certainly don't meet the dual 8" specs either.

brianca....

 

[Greg_R]

These numbers are only for the person's design. Driver excursion, efficiency, and enclosure type also affect the max SPL. IMO, setting main speakers to small (regardless of size) will improve power handling, distortion, & bass response.

 

[brian a]

So then you would agree that the Diva line, aside from the 6.1s, are unable to play cleanly at reference levels even with set to small?

brianca..

 

[Eujin]

Brian, I think that being able to play a 6.5" driver at 90db levels at 80Hz is already pretty good. Unless you like listening to stuff at deafening levels, the figures provided should not overly alarm you. If you're not alarmed at the current speakers that you own, it should be an indicator that actual real-world listening could be very different from perceived performance based on measurements (unless, of course, you're going to be sitting in an anechoic chamber).