Not sure if I have problem with my receiver

[DanH12]

I recently purchased a pair of the Pioneer sp-fs52 floorstanders, the Pioneer sp-c22 center speaker and a pair of the Pioneer sp-bs21s for the rears. They are all hooked up to my Sony STR-DE845 receiver. I have watched several movies on the speakers and am not completely happy with sound coming from the center speaker. The center speaker produces music fine but at the receiver's regular 8 ohm setting, voices and some sound effects are bright and harsh sounding. I thought that maybe the speakers were not being delivered enough power so I switched the power setting to 4 ohms on the receiver since the speakers are rated at 6 ohms. Voices and sound effects then sounded quite a bit less harsh but they now sounded very slightly muffled. The 4 ohm setting is for the front left and right speakers so I am not sure why that affected the center speaker but it did. I am more happy with the 4 ohm setting but my receiver gets very warm at this setting and I am concerned that this might damage my receiver or my speakers. I want to note that I also had this same problem before with previous speakers which were JBL Sat10 speakers. The front left and right and rear speakers sound fine.

I am wondering if maybe there is a problem with my center channel on my receiver. I had my JBL Sat10 speakers for 15 years and never noticed this problem with the JBL center channel until one year ago. I thought that maybe there was a problem with the speaker but now the same thing is happening on the Pioneer center speaker. All of my speakers have always been set up in the same location and position in my room. My center speaker sounds fine when I run test tones through my receiver. I do not have a subwoofer. The front left and right speakers are set to "large" and the center is set to "small > 90hz". The rear speakers are also set to "small >90hz". I wonder if maybe the receiver is becoming strained because there is no powered subwoofer to take care of the lower frequencies?

Does this sound like maybe my receiver could be going? Is it possible my receiver is just not producing enough power to the speakers? Do speakers tend to sound brighter when they are under powered? My Pioneer speakers are rated at 6 ohms and I am wondering if they really need a separate dedicated amplifier?

I am wondering if maybe I should buy a new receiver and see if the problem is resolved. Do more expensive receivers deliver cleaner power? Am I better off with one higher end receiver (approx $700-1,000) or a cheaper mid grade receiver and a dedicated power amplifier to power the front and center speakers?

Any help is greatly appreciated.

 

[agarwalro]

First and foremost, revert the speaker impedance setting back to 8 Ohms. As explained here, you're potentially delivering less power to the speakers. At the 6 Ohm setting, the reduced harshness with slight muffled sound is the result of clipping distortion artifacts being removed. IMO, neither the FS52 speakers or the amp are fit for full range sound. Use a 90 Hz crossover on all (including front) speakers to free up some power reserve in the amp.

Is the center speaker properly placed and not pushed to the back of a shelf?

IMHO, the receiver is not necessarily due for an upgrade and instead the addition of a sub is critical.

 

[DanH12]

Setting the receiver back to 8 ohms and setting the front speakers to "small" and to output >90hz got rid of the harshness in the center channel. I did read the link you sent me and it made sense but why does my receiver appear to get warmer when I set the impedance switch to 4 ohms. From what I understand, the purpose of switching to 4 ohms is prevent the amplifier from overheating my reducing the amount of current supplied to the speakers. If this is true, then it seems that the 8 ohm setting would produce more heat and it does not seem to. Why is this?

You also mentioned that at the 4 ohm setting on my receiver, that the reduced harshness was the result of clipping distortion artifacts being removed. Isn't that a good thing. Don't I want any and all distortion removed?

Lastly, how much would I have to spend to buy a receiver and speakers that could run at full range without a subwoofer?