Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: very good but doesn't sound like them

I just bought this CD and it is very good but I have heard the Carter Sisters early recordings/performances and it is hard to believe it's them. I can't even tell who is singing. I know they are older but sometimes it almost sounds little girlish. I enjoy it and I was under the impression Helen sang lead on many of the songs but none of them sound like her.