Hilde45.
I have never heard the Volti but it might just come down to quality of parts. the mid horn is mad of wood where Klispch is made of thin plastic (even the La Scala). Klispch has stamped baskets and all in all just seem cheaply put together to me (I think they sound fine but not refined enough for me).
I would like to read more about the drivers in the Volti as the drivers are 90% of the sound quality IMO. they could be amazing drivers or very average, there is simply not enough information for me to know without listening. Measurements would help these small brands sell speakers as it would take out the some of the risk as a buyer.
With that said I think the price to build quality looks really good on these. I expected them to be just over $10,000. At $7500 I would try these if I was in the market.