I don't know what the impedance curve looks like on the Vantage but, the figure likely drops as frequency increases due to the electrostatic panels. But.....
The crossover frequency is higher on the Vantage than the Summit, something like 400 Hz I think, therefore it's built in amplifier will be handling the power requirements up to this frequency. Since the range from 400Hz on up typically doesn't require the power absorbed by the lower frequencies, then it's really only the rather low impedance at 20Khz, or the upper end of the spectrum, that is of concern. I doubt seriously this particular speaker needs much more than a 75 or 100 watt amplifier for a moderate size room at normal listening levels. However, it does need an amplifier that remains happy when driving a momentary 1 ohm load and, there we might have a problem.
Modern solid state amplifiers using a moderate amount of feedback (which comprise most of the market today) should not have a problem with this load for normal music program material - where upper treble energy is very light. Tube amplifiers, especially OTL types, might have more of an issue with this demand. For these amplifiers, its best to consult with the amplifier manufacturer for their comments on driving this particular speaker. But for solid state amps, I think you will be fine.
By the way, I have listened to the Vantage driven by a Parasound amplifier (I don't remember the model but, I think its was their 75W classic model) and, it sounded really, really, really good. Just really good.
The crossover frequency is higher on the Vantage than the Summit, something like 400 Hz I think, therefore it's built in amplifier will be handling the power requirements up to this frequency. Since the range from 400Hz on up typically doesn't require the power absorbed by the lower frequencies, then it's really only the rather low impedance at 20Khz, or the upper end of the spectrum, that is of concern. I doubt seriously this particular speaker needs much more than a 75 or 100 watt amplifier for a moderate size room at normal listening levels. However, it does need an amplifier that remains happy when driving a momentary 1 ohm load and, there we might have a problem.
Modern solid state amplifiers using a moderate amount of feedback (which comprise most of the market today) should not have a problem with this load for normal music program material - where upper treble energy is very light. Tube amplifiers, especially OTL types, might have more of an issue with this demand. For these amplifiers, its best to consult with the amplifier manufacturer for their comments on driving this particular speaker. But for solid state amps, I think you will be fine.
By the way, I have listened to the Vantage driven by a Parasound amplifier (I don't remember the model but, I think its was their 75W classic model) and, it sounded really, really, really good. Just really good.