Harshness in tweeters: the price of transparency?
One or two observations. The Focal Micro Utopia Be are 89dB with a 3 ohm minimum impedance (8 ohm nominal). As such, they require an amplifier that doubles output into 4 ohms, which neither your Redwine 30.2 or SET amp do, the result being frequency imbalance that emphasizes the mids and top end and under emphasizes the bass. The Stereophile review states the speaker "can be unforgiving of bright material". Frankly, I believe your problem starts here, and your amplifier mismatch exacerbates the problem. You might look at a Pass Labs XA-30.5 amplifier. Phenomenal Class A solid state amp that doubles power into 4 ohms. The rest of your equipment is up to the task, it seems to me. Otherwise, other speakers may be in order...but if you intend to keep the amps, then the speakers ideally need to be more sensitive (95dB+), and they need to have a flat impedance curve that doesn't dip below 8 ohms (maybe 6 ohms at the outside). Coincident, Devore, Audiokinesis, Merlin are a few alternatives. |
From Stereophile: The Focal-JMlab Diva Utopia Be's ported enclosure was tuned to approximately 27Hz, with minimum impedance of 3.38 ohms at 100Hz. I would judge this speaker to be of average difficulty to drive for any amplifier comfortable with a 4 ohm load, and I would rate its nominal impedance at 4 ohms. The speaker's sensitivity measured approximately 87dB/2.83V/m.Maybe this isn't your speaker? The Redwine may be able to drive 4 ohms, many amps are, but that does not mean it doubles power into 4 ohms compared to its power into 8 ohms, and since Redwine does not publish the 4 ohm spec for the 30.2 there's no way to verify it. I recall Vinnie stating on another website that it did not. The Street dot com says this in their review: The amp is capable of delivering 30 watts per channel into any speaker load from 4 to 16 ohms.That's essentially what tube amps do...deliver the same power into various impedance loads, and it's why many tube amps don't sound right on speakers with wide impedance swings. 30 watts into 4 ohms produces fewer decibels than 30 watts into 8 ohms, thus perceived pronounced upper frequencies. You have Voltage Paradigm speakers, and two Power Paradigm amplifiers. A mismatch. Ralph Karsten has a white paper on this topic here. This is a moot point since you state you will not change amps. So, perhaps a change to Power Paradigm speakers (like Devore, Coincident, Merlin, Audiokinesis...) will help get you closer to where you want to be. Anyway, good luck. |
I noticed the speaker specs I copied into my post above were incorrect. These are yours, yes? Micro Utopia Be 2-driver, 2-way, ported-box speaker 5 ohms minimum impedance, as you said. The Stereophile measurement specs I listed were for the Diva Utopia Be, which is a different model from yours. Just wanted to correct the error. |
