As of late everytime I have a loud low frequency output I'm loosing my higher freq. Is this my amp giving up already?
I've a Yamaha RXV 2400 with a sunfire TGA 5200.
I think you have a mismatch between your speakers and your receiver. Your receiver is rated 6 to 8 ohms. I have been around the net and this receiver is prone to problems with four ohm loads.
Now your towers are rated at 4 ohms. However the situation is worse, as your towers have a passive crossover at 100 Hz. this is never to be recommended in my view. The phase angles are going to about as bad as your will find, and the current demands are going to MUCH higher than even the four ohm rating would suggest. Also don't forget that the rated impedance of a speaker does not mean much as there an impedance curve. RGB do not publish the curve, nor do they quote the minimum impedance. From the design set up, I have to say that the minimum impedance could easily be falling to the two ohm range at some point, and with a very difficult phase angle to boot.
There are two possibilities here.
Those RGB speakers have a protection circuit to the tweeter. Now when an amp clips, and this usually occurs when an amp is attempting to dive LF into a low impedance load, then when it can't meet the current demands THD rises and the tweeter receives the distortion products. So I'm pretty sure your tweeter protection is cutting in.
Now it may be that it has been activated so often that it is now kicking in before it should. Often these types of circuits don't tolerate being activated constantly. More likely however, the load presented by these speakers to your receiver, is causing the output devices of your receiver to fail, and clipping is starting to occur at lower and lower power levels.
Those speakers are going to require a hefty amp, with huge current reserve.
You need to pick an amp that delivers at least double the power into a four ohm load that it will deliver into an 8 ohm load. I would also see if RGB will tell you what the minimum impedance of your speakers are, and at what frequency it occurs. It will also be nice if they would share with you the phase angle between voltage and current at that frequency. Also knowing the frequency of the maximum phase angle would be nice, then the power factor required to power the speakers could be calculated and we would know for certain, how low an impedance the amp has to be comfortable with. It would not be out of the question that an amp driving those speakers might have to be comfortable driving a two ohm load because of the phase angles.
Recently I received privileged information from a manufacturer about these parameters where there was a passive crossover in the same region as yours. The impedance curve was an absolute amp torture test, yet the speakers were rated at 8 ohms! The speaker was in fact 8 ohms only above 900 Hz and at the two reflex tuning peaks. At the rest of the spectrum it was below 6 ohms, and at the low pass mid pass crossover region it was 3 ohms. They did not send the phase graph, but it had to be horrible. Even without allowing for that, however, the speakers obviously required a robust amp. A consumer buying the speakers from the spec sheet, would have thought he was buying 8 ohm speakers. He would be buying nothing of the sort!
This post highlights why I'm consistently advocating for the phasing out of the whole concept of the receiver. High current devices make heat and usually lots of it. Last time I checked the specs of the microprocessors used in receivers and pre/processors their absolute maximum safe operating temperature before destruction was 70 degrees C. So actually the internal operating temp should be 50 or less. That would be almost impossible to achieve with multiple high current amps and the large associated power supply required.
So the solution is to move to separates, or better still to powered speakers with active crossovers and an amp for each pass band. Take your speakers for instance, even if only the 100 Hz crossover were active, the improvement in performance would be highly significant.
So my advice for now is to get a nice multichannel amp that will produce twice as much power into a four ohm load as eight. If RGB tell you after inquiry, that the load actually presented is significantly below four ohms, or there is a highly adverse phase angle, then you will have to get amplification that is also comfortable with 2 ohm loads.
