The HPM-100 is a boom'n'sizzle rock/pop loudspeaker. The L-1090 (I owned a pair for 9 yrs and they anchored my main system) is a serious loudspeaker that can kick ass on everything from rock to acoustic pop, jazz, thrash, large scale orchestral, chamber music, big band, you name it. They also do a great disappearing act and image like mo-fo's.
Whatever you like from the L-570 the L-1090 will give you much more of it in terms of clarity, dynamic range, and frequency extension. To put it in perspective, the ADS product line of the mid-'80s included the L-1590, L-1290, and L-1090. They were all sealed cabinet twin-woofer towers with dome midrange and tweeter. All three models shared the exact same midrange and tweeter and varied only in cabinet and woofer size. The L-1590 was Telarc's monitor of choice at this time.
Given that the L-1090 is a sealed cabinet design, the bass is not thumpy or especially strong, but it's there and is very musical, quick, and well blended with the upper drivers. I also got much better bass when I upgraded to a 200 wpc high current high damping factor power amp.
So I can't give you advice on which to get because we don't know how you intend to use the second pair of speakers, so instead I'm trying to share what you can expect from the L-1090's. The HPM-100s will probably sound stronger in the bass because it's a 12" driver in a ported cabinet, but I suspect that the bass will mostly be a thump at around 50 Hz and drop off quickly from there. The ADS will have audible bass down to at least the low 40's and maybe lower depending on room placement.
Whatever you like from the L-570 the L-1090 will give you much more of it in terms of clarity, dynamic range, and frequency extension. To put it in perspective, the ADS product line of the mid-'80s included the L-1590, L-1290, and L-1090. They were all sealed cabinet twin-woofer towers with dome midrange and tweeter. All three models shared the exact same midrange and tweeter and varied only in cabinet and woofer size. The L-1590 was Telarc's monitor of choice at this time.
Given that the L-1090 is a sealed cabinet design, the bass is not thumpy or especially strong, but it's there and is very musical, quick, and well blended with the upper drivers. I also got much better bass when I upgraded to a 200 wpc high current high damping factor power amp.
So I can't give you advice on which to get because we don't know how you intend to use the second pair of speakers, so instead I'm trying to share what you can expect from the L-1090's. The HPM-100s will probably sound stronger in the bass because it's a 12" driver in a ported cabinet, but I suspect that the bass will mostly be a thump at around 50 Hz and drop off quickly from there. The ADS will have audible bass down to at least the low 40's and maybe lower depending on room placement.