affordable, durable, compatible. I am using these on a speaker formula, as I cannot afford what I desire. My project starts with cv ls-10 crossovers, American acoustic cabs, 3 way. I am converting with these subwoofers, xp-104 5′ sealed midrange, peerless silk domes. I have tried to match perimeters to best of my ability, for the conversion. my decibels are still not exact, but close. my resistance is not exact but close. my total investment. cabs, 40.00, mids 22.00, subs 47.00, tweeters 36.00, crossovers 22.00, For a 167.00 investment and labor, compared to a thousand dollar investment, I think that I have done very well. oh they measured 3.6, even on both. I know my methods to all the professional are primitive, as I do not have the complex mathematical skills that are required. I have done a ton of specification, and perimeter research. All I can do now is work with the haas effect. I am going 4 ohm sub, 4 ohm mid, 6.4 tweet, with cv crossovers. this will be a home setup. I am looking for a setup that wont put a load on amplifier, but will achieve sonic linearity, with solid bass. Went 8 ohms in past did not work for me. Like low volume, with high output. thank you also amazon, for the excellent service. They were double boxed together, with excellent packing. you have made this affordable for me, so I can continue my project. thank you again.