Peavey Hisys 2XT 8 ohm as tops with 115XT 4 ohm bins?

[grantr22]

Hi all, my first post. 

I have a pair of trusty Hisys 2XT (earlier rectangular model, black & green) and these are the less common 8 ohm version. I'm considering buying a pair of 115XT bins from the same era to use with them, but these are 4 ohm. I understand that the crossover in the 115XT will present a 4 ohm load to the amp regardless of the impedance of the tops used, and the blurb for the 115XT says 2XTs of either 4 or 8 ohm can be connected to the high pass out of the 115XT. But I'm concerned that the db output from my 2XTs as tops will be quiter than the output would be from their 4 ohm equivalents in this setup?

My theory is based on: an amp driving a 4 ohm load will generally provide approx 2 thirds more power than when driving an 8 ohm load. So with the higher impedance of the 8 ohm cabs, these will draw less current through the crossover, and therefore there will be less output from the tops, when compared to using 4 ohm tops, for a given power delivery from the amp driving the 4 ohm load of the 115XT crossover.

I'd be very grateful for some guidance here, many thanks.

[agedhorse]

Not a practical problem, as you will typically need 3dB more output senstitvity from the subs to match up anyway.

The high pass output will be about 1 octave higher with the 8 ohm top than 4 ohm top, It depends on which impedance the high pass freq. was specified at. In practice it may not matter as this isn't going to be suitable for any kind of critical application anyway.

[grantr22]

Hi thanks for your post, you're right it's not for anything quality-critical, I just don't want to be loosing out on a portion of volume when I need it (which I do on occasions). So you think the difference would be un-noticeable?

[dboomer]

The sub will get twice as much power  as the top.  That's probably close to correct ... might be a bit better or a bit worse.  It depends on the sensitivities and the way the crossover circuit is wired.  It shouldn't hurt anything.

[grantr22]

That's what I was concerned about Don, too much bass not enough mid-high and having to EQ the heck out of it

[mkfs9]

Are you going from amp to sub to top using built in x over, if so the speakon wiring is different on the link lead on the sub end.used to have this set up years ago

[grantr22]

Yes, already got link leads wired for pair 2 at one end. Thanks