These sit in different price classes - Magnepan 1.7x costs roughly 5x what KLH Concord does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass |
B |
KLH Concord digs deeper - 28Hz against 40Hz. |
| Amplifier needs |
B |
KLH Concord is more sensitive (94dB vs 86dB), so it goes louder on the same amplifier. |
| Amplifier match |
B |
KLH Concord is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Size |
depends |
Magnepan 1.7x is easier to place; KLH Concord is bigger, which usually goes with fuller bass. Your room decides. |
| Cabinet |
depends |
Dipole vs Ported. |
| Price |
B |
KLH Concord is cheaper - $1,000 against $5,000, about 80% less; arguably a different class. |
A Magnepan 1.7x
B KLH Concord
depends neither is better in the abstract - it turns on your room, placement or how you will use them.
Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
KLH Concord is the easier recommendation: it leads on most of the measured areas and costs less. Take Magnepan 1.7x if its size, looks or fit in your room suit you better. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 40Hz anyway, so judge these on the other rows instead. In a large or open-plan room, KLH Concord has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Magnepan 1.7x is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.