Quote Originally Posted by pdhanwada
I have B&K 7270 200 X 7 at 8 ohms and 375 X 7 at 4 ohms power amp and Paradigm Signature S-4 Speakers. The preamps min volume is -96 db. I dont hear any sound from the speakers until -60 db.
These numbers are completely arbitrary and vary from manufacturer to manufacturer. Ignore them.
My max volume is at -15 db. I am not sure If I am driving my speakers/AMP hard. at -15 db I dont see any clipping. As I dont have a sub right now I feel base is not powerful enough. I am soon going to get a sub anyway.
S4's are rated to 62 hz, is it any wonder why you're not getting enough bass? It is only a standmount after all and therefore inherently limited. If you want more bass, try placing the speakers closer to the corners for some reinforcement until you get the sub.

As for driving your speakers too hard, use your ears and some common sense. If you hear clipping and/or compression, you are driving the amp too hard and likely risking severe damage to your speakers. Plus, at 91 dB's sensitivity, I'd imagine it would be unbareably LOUD at this point as well unless your listening room is ginormous. Banging your amp against the rails is detrimental to both amp and speakers.

One more thing is B&K getting hot. But I see no clipping until this point. Does the life of the amp has any impact because it is getting hot.
As a class A/B amp, it will be somewhat wasteful by nature (heat is simply wasted energy, nothing more). That said, electronics in general abhor heat. Your speaks are pretty efficient so I'm surprised it runs hot. I ran a B&K for 16 years driving 4 ohm speakers and never encountered anything untoward nor do I remember it running hot.

My question for you guys is how do I determine when I am running the system too hard.
Use your ears. If you're into clipping, you're running it too hard.

Another thing I am planning to do in next few days is to bi amp my speakers. I am only using three channels right now. L,R and center out of 7 channels available in the amp. I intend to use two more to biamp my L R speakers. I know power usage in the amp will increase but does the amp sustain the load. Have anybody done this before let me know.

Thanks
Plenty. Does it help? You tell us. I've never been a proponent of biamping, particularly with the same amp. SS on the bass and tube up top? OK, I can understand that reasoning. However, unless your B&K has dedicated power supplies for each channel (IOW, it's a true mono design for each channel, which it may be), all you're doing is draining the power supply by hooking up more channels. Even if it is a true mono design, I think you're going to be challenged to hear any improvement. Of course, you'll be able to feel the difference immediately as your wallet will be considerably lighter after buying extra wire. Still, it's your money so do whatever you think is best.

Hope this helps.