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My system's high frequencies hurt my ears

Well, to be perfectly clear it doesn't always hurt my ears but I've been getting a little fatigued at times and I'm trying to diagnose the problem. A few nights ago I was listening to a new 24/96 The Doors first album release and had to stop playback. I switched over to The Eagles Greatest Hits, 16/44, and found some happiness there but I wasn't completely satisfied. Perhaps some of this is psychological, maybe I was feeling a little extra sensitive, but I'm sure I've had some issues with high frequencies in the past.

Here's my setup:

Serving all music, ripped to WAV by Exact Audio Copy or downloaded via high rez sites, via Windows 7 computer running J River set to WASAPI output. Sending signal via USB to Audiophilleo USB/SPDIF converter to PS Audio Digital Link III DAC. From DAC using Nordost Baldur unbalanced RCA interconnects to PS Audio C-100 Control Amp. Speaker wires are Nordost Blue Heaven. Power cables are PS Audio Lab Cable from wall to PS Audio Duet Power Conditioner. From there I use another Lab Cable for the amp and a PS Jewel cable for the DAC. The wall plug is on its own circuit with nothing else connected. Speakers are my old but good Mirage 1090i's.

Aside from perhaps the age of the speakers do you guys see anything that stands out? I spoke to a technician from Mirage and he suggested I'm doing too much signal processing which could be a cause of uncomfortable high frequencies.

Looking forward to hearing your thoughts.
robpriore
fleib
1,124 posts
 
I'm not exactly sure what the problem is, but it might be ultrasonic noise making the high frequencies sound bad. This is a more common problem than realized, especially with electronics that have wide bandwidth. I don't know if this will be a fix, but it could save you a ton of grief, if it works. What I'm suggesting is a zobel network at your speaker input to possibly tame the ultrasonic noise. There's no guarantee, but I think it's worth a try.

If your speakers are 4 ohm (?), get a 10 watt 6 ohm resistor and twist the end to a 0.3 uF speaker capacitor. Put one end in the + speaker terminal and the other in the - terminal. These parts are relatively inexpensive at Madisound or Parts Express. I'm not familiar with your speakers, but the Mirage I've heard weren't harsh and one could listen on-axis. If it works, you could replace the resistors with non-inductive types - still cheap compared with alternatives, and if it works, any speaker hooked up to this system will benefit.
robpriore OP
35 posts
 
They are 6 ohm. What size resistor and capacitor for 6 ohm?
fleib
1,124 posts
 
If the speakers are rated at 6 ohms, it's a little tricky figuring out the individual driver impedance. The tweeter could be either 6 or 8 ohms. Maybe Mirage could supply this information. I suggest trying an 10 ohm resistor in case the tweeter is 8 ohms. If you find out the tweeter is 6 ohms, you could switch to an 8 ohm resistor. It will work in either case, if this is in fact the problem. A 0.47uF cap should do do the job in either case.

The way this works is by putting a load in parallel with your speaker. The resistor limits the rising (w/frequency) impedance of your speaker. The cap determines the frequencies that are affected. So you want a cap that will cut in beyond 20K - the smaller the value of the cap, the higher the frequency. The resistor value should be greater than the impedance of the drivers. If this works you can tweak the values of the components. Generally speaking, 2 ohms greater than a drivers impedance is a good place to start. With the cap value - a lower value will keep it further from the audible band, but could be less effective. This worked for me with one of my transistor amps that has response beyond 100K. It was unlistenable with a certain transistor preamp until I tried a zobel. With a 6 ohm tweeter I'm using a 0.33uF cap and a 8 ohm resistor.
robpriore OP
35 posts
 
So i take the two resistors, twist together, and then connect one side to the + terminal and the other to the - terminal. If i did that with a wire it would short out right? The resistors won't cause a short?
fleib
1,124 posts
 
Twist together 1 resistor and 1 capacitor and connect them as you described. This is similar to part of a crossover that goes to ground, only external. It won't short out your speakers, but there's no guarantee it will be a cure. If it's a harsh sounding tweeter... The last Mirage speakers I heard were M1, years ago. They had a soft dome, I believe, and it wasn't harsh. There's a driver manufacturer, Scan Speak I think, that sells speaker wire with zobels built in - just for this problem. I can't think of a way that you could damage anything connected as described. Make sure you have at least a 5 watt or 10 watt resistor. Poly speaker caps are normally rated at least 200V. Caps - Parts Express # 027-206. Resistor # 005-(value). That's about $10 in parts + shipping.
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