I plan on upgrading my surround speakers but before I do so I had a question about my setup. I have jbl sat10 speakers and a jbl bass16 subwoofer. My speakers are rated at 8 ohms. I do not know what the impedance rating of the subwoofer is. My receiver is a Sony STR-DE845. The subwoofer is connected to the front left and right speaker inputs on the receiver because the subwoofer has no subwoofer/lfe jack. The actual front left and right speakers are connected to the other set of front speaker inputs on the receiver. So I have two sets of front speaker inputs on the receiver labeled front (A) and front (B) and I am using both (A) and (B) with my setup. I am able to switch my receiver to either the 4 or 8 ohm setting for the front speakers using a switch on the back of the receiver. On the back of the receiver, it says that when using the front (A) and (B) speaker terminals together, the 4 ohm setting should be used if all speakers are rated at 8 ohms. As far as I know, the receiver had always been set to the 8 ohm setting and it was only a few weeks ago that I noticed the warning on the receiver to use the 4 ohm setting when using the front (A) and (B) terminals together. In spite of this, we had always been happy with the way the speakers sounded.
On my receiver there is a knob that allows me to switch between using the front (A) terminals, front (B) terminals, front (A) and (B) terminals together and just not using any front terminals (off). When I learned about the caution on the receiver to use the 4 ohm setting when using the front (A) and (B) terminals together I only used the front speaker terminals with the front left and right speakers connected (front A inputs) and using the 8 ohm setting. This sounded better as the sound coming out of the front left and right speakers was clearer and the treble was quite a bit smoother and not somewhat hurting my ears like had happened before. While still using the 8 ohm setting, I had switched back and forth between the front (A) and front (A + B) setting quite a bit and still found that using just (A) sounded better than front (A + B). I think this is because the front speakers were underpowered when using (A + B) at the 8 ohm setting and when using just (A), the speakers getting just the right amount of power. Next I tried what the receiver recommended and used the 4 ohm setting while also using the front (A + B) terminals at the same time. This time the treble and high frequencies were smoother and not as ear piercing but there did appear to be some clipping going on. I heard some popping/crackling noises and it also sounded like there was a very subtle buzzing coming out of the front left and right speakers. When I switched back to the 8 ohm setting, these noises went away so I figure the front speakers were being overpowered even though the receiver said to use the 4 ohm setting when using (A + B). The subwoofer has its own power supply and I think the 4 ohm setting on the receiver is not necessary because of this. Also, matters are complicated because I don't know what the impedance rating of the subwoofer is.
The problem with my set up is that when I use the front left and right speakers with my subwoofer, the speakers don't sound as good as when I use just the speakers by themselves (front A inputs instead of A + B). This means that if I want to use both at the same time I have to deal with somewhat ear piercing treble coming out of the front left and right speakers and I suspect this happens because the front left and right speakers are underpowered at the 8 ohm setting. I say this because as I explained above, the receiver says to switch to the 4 ohm setting when using the front A and B terminals at the same time but when I do this it overpowers the front left and right speakers. When I use the 8 ohm setting while using (A + B) at the same time, I don't think the front left and right speakers are getting enough power. So if I want to use my subwoofer then the front left and right speakers are getting either not enough or too much power and won't sound quite right. This happens even when I adjust the gain on the subwoofer lower or higher.
I know this is a long post but the problem is complicated to describe. Ultimately I want to know if I am damaging my front left and right speakers by possibly under-powering them using the 8 ohm setting on the receiver and using the (A) and (B) front terminals at the same time? I noticed that my speakers started sounding worse about a year ago and now all three front speakers sound screwed up. This is why I was concerned that somehow my setup could have damaged my speakers over time. I am afraid that if I upgrade I will damage the new speakers with this setup. I was going to upgrade to the Pioneer SP-BS22-LR speakers. Those are rated at 6 ohms and that further worries me since my receiver does not have a 6 ohm setting.
All help is appreciated.
