There are a couple of pairs available on this site, you use to be able to buy Irs betas a few years ago for under 6k, times have changed, I would check for the same things as mentioned by other members, I have IRS epsilons and also had in the past IRS sigmas, renaissance 80’s and renaissance 90’s so I know the sound of the newer infinity emit’s and emim’s, I auditioned a pair of IRS betas a few years ago and thought they sounded awesome, they had a big 3d sound stage, great imaging and the best bass I ever heard, I had to lower the bass level down to the 10 O’clock position or less for it to sound balanced with the high frequency drivers, in comparing the IRS epsilon to the IRS betas, obviously the betas had way more bass output but the bass was not as quick as compared to the epsilons bass, I believe this had something to do with the epsilons improved SCU box , the sound stage was deeper and slightly wider on the betas being that they are dipole and because of the semit, that said the newer style planar drivers used in all the above mentioned infinity speakers have way less coloration than the older style planar drivers used in the betas, to me the betas planar drivers have a ringing sound to them compared to the newer planar drivers used in the infinity renaissance 80, renaissance 90, IRS omega, IRS sigma and the IRS epsilon, If you didn’t have one of the newer infinity speakers to compare to you probably might not notice the ringing sound, that said if you have a big enough room for the batas I say go for it, I have my epsilons in a 19x15 room and it’s still too small for them.