Check out the frequency response graph of the Celestion SL700 in this Stereophile review:
http://www.stereophile.com/content/celestion-sl700-loudspeaker-1991-measurements
While there is a big dip in the frequncies between 10k and 20k the spike beyond 20k would have to have an effect on the sound of the speaker,IMHO. That spike is found with many metal tweeters.
http://www.stereophile.com/content/celestion-sl700-loudspeaker-1991-measurements
While there is a big dip in the frequncies between 10k and 20k the spike beyond 20k would have to have an effect on the sound of the speaker,IMHO. That spike is found with many metal tweeters.