Paulraphael, what you are describing about the Triangles is common. The upper mids/lower treble is a bit harsh.
This is related to three things. First, Triangle keeps as much crossover out of the mid - tweeter as they can. Traditionally, a single capacitor(in series with the tweeter) was the only crossover component used in this region by Triangle. They want no intrusion of a capacitor or coil, which in their opinion(and I agree) these components can only slow down the music, reign in dynamics, and change the sound. Secondly, the mids and tweeters overlap more in their speakers than what is usually encountered. The midrange operates as high as it can go, which results in beaming and uneven response which can show up in raggedness and distortion. The tweeter also plumbs down lower than it probably should, again leading to raggedness and distortion. Thirdly, emphasizing with my second point, I find the response of the tweeter to be a bit unsettled in general. Depending on ancillary equipment, volume, musical tastes, and room, this tweeter can easily turn nasty. I find this from a great many metal domes, but factor in the lack of crossover to filter out the lower frequencies the tweeter sees, and you end up with exactly what you describe.
Do not try to do too much other than setting the speakers on a good pair of spikes. Triangle speakers eschew the use of most of the damping and vibration control solution sacred cows of audio. That's the way they are designed. Like a violin or other musical instrument, Triangle speakers(like most speakers before the 1970s), are supposed to "sing along with the music". These resonances and vibrations in no way add up to shrillness or the problems you are seeing.
I would say the first thing you need to do is move away from the StraightWire Rhapsody 2 interconnects. StraightWire has always produced some of the most forward cables in the business, and in many cases, they are downright bright. Most audiophiles no longer talk about or know much about StraightWire these days, but think back to about 1990 and the lightbulb will come on for many. Whether you move to Cardas, or most other copper interconnects(you may also want to think about Alpha Core Goertz or Analysis Plus), I think you will see a fair amount of your problem solved there.
Second, you also need to find a different speaker cable. AudioQuest cables do not nearly spotlight brightness as mush as StraightWire, but they also do nothing to tame it. Again, move to something along the lines of the interconnect you go with.
Most of your problem should be solved by cable. Although I am not the world's biggest advocate of cable solving problems, in your case, I think the solution is appropriate and will work. The combination of cables which highlight detail and speed, coupled with what I laid about the Triangle crossover/tweeter is a recipe for pain.
Apart from my suggestions, it seems wise to also investigate the tube suggestion(can't hurt), but I think cable will be an area which you will need to address in your system regardless of what happens otherwise.
This is related to three things. First, Triangle keeps as much crossover out of the mid - tweeter as they can. Traditionally, a single capacitor(in series with the tweeter) was the only crossover component used in this region by Triangle. They want no intrusion of a capacitor or coil, which in their opinion(and I agree) these components can only slow down the music, reign in dynamics, and change the sound. Secondly, the mids and tweeters overlap more in their speakers than what is usually encountered. The midrange operates as high as it can go, which results in beaming and uneven response which can show up in raggedness and distortion. The tweeter also plumbs down lower than it probably should, again leading to raggedness and distortion. Thirdly, emphasizing with my second point, I find the response of the tweeter to be a bit unsettled in general. Depending on ancillary equipment, volume, musical tastes, and room, this tweeter can easily turn nasty. I find this from a great many metal domes, but factor in the lack of crossover to filter out the lower frequencies the tweeter sees, and you end up with exactly what you describe.
Do not try to do too much other than setting the speakers on a good pair of spikes. Triangle speakers eschew the use of most of the damping and vibration control solution sacred cows of audio. That's the way they are designed. Like a violin or other musical instrument, Triangle speakers(like most speakers before the 1970s), are supposed to "sing along with the music". These resonances and vibrations in no way add up to shrillness or the problems you are seeing.
I would say the first thing you need to do is move away from the StraightWire Rhapsody 2 interconnects. StraightWire has always produced some of the most forward cables in the business, and in many cases, they are downright bright. Most audiophiles no longer talk about or know much about StraightWire these days, but think back to about 1990 and the lightbulb will come on for many. Whether you move to Cardas, or most other copper interconnects(you may also want to think about Alpha Core Goertz or Analysis Plus), I think you will see a fair amount of your problem solved there.
Second, you also need to find a different speaker cable. AudioQuest cables do not nearly spotlight brightness as mush as StraightWire, but they also do nothing to tame it. Again, move to something along the lines of the interconnect you go with.
Most of your problem should be solved by cable. Although I am not the world's biggest advocate of cable solving problems, in your case, I think the solution is appropriate and will work. The combination of cables which highlight detail and speed, coupled with what I laid about the Triangle crossover/tweeter is a recipe for pain.
Apart from my suggestions, it seems wise to also investigate the tube suggestion(can't hurt), but I think cable will be an area which you will need to address in your system regardless of what happens otherwise.