I can't think of any in that setup...the advantage may be the other way around because you can match all speakers.
If it is primarily HT, I would definitely go with bookshelf/monitors. Since you need Sub-woofers for HT anyway, why pay for redundant capability in your floostanders that you will be crossing over to sub-woofers anyway? Not only that, but you can usually get a higher quality bookshelf/monitor since the designer can concentrate his/her efforts and material expense on the mids and highs -- and you'll get higher quality lows because it costs $$$$ to get floorstanders that do bass well. I'd rather have a higher end bookshelf/monitor than a mediocre floorstander. Again -- why do that if you're just going to cross the bass over to the sub-woofer anyway? You can save that money, eliminate the redundancy, and end up with a better system by going with bookshelf/monitors and sub-woofers. But, don't skimp on the sub-woofers.
The deal there is that you'll get a potentially better dynamic (even crossing over to 80hz/small) using the 60's because of the extra bass driver, or more drivers! Why?...more emphesis on the affected frequencies, cancellation of distortion between 2 bass drivers, reinforcement of transients, more efficiency, etc.
The 20's, if I'm not mistaken, have 1 midbass (typical monitor), and the 60's have 2 midbass woof's, yes? All things equal, you'll have a bit better dynamic ability with more drivers. Again, all things equal. This advantage is certainaly more afforded, the bigger the room, etc. In a setting that's a smaller space, the 20's will sound more dynamic and powerful than in a larger space.
Also, the 20's "roll off" higher up (even though your processor rolls off bellow the "small setting") than the 60's, which will probably have more bass energy pressent bellow the "cut off" nonetheless. This is more noticeable in a small room, and less desireable often. In a big room, probably a benefit to reinforce what the sub's putting out bellow 80hz, etc.
Basically, in a larger room, the floor standers will sound sronger, while the 20's will be better suited (more than enough if set up right) to smaller spaces.
Yet, get either set up for proper coupling with the room, cross em over right, and you'll have good dynamics (If you don't treat acoustics right, you'll need to sit proximally closer with those designs, so you hear more "dirrect sound" vs. reflected...trust me.)
I have the 60s in my HT setup and definitely heard an improvement when I switched the fronts to large vs small. The cost of a good second sub will be more than the cost of going from the 20s to the 60s and give you better overall sound for both HT and music IMO. The footprint will also be the same as you need stands for the monitors and will add to the cost.
with all receivers and processors , when you set a large speaker to small, the sub is more active, if you set the speaker to large fronts the towers do some of the load from all channels aswell as the sub, but if you have a reciever or a processor with individual crossover adjustments, you can set all speakers as small and asign the proper crossover to each channels ability, I happen to like this feature but this is only optimal when configuring all small speakers in the set-up..just my opinion...I also think that some movies are great in 2 channel, but alot need 5.1 or more to really get the WOW. I do agree that bookshelfs are the way to go, but make sure if possible that you can safely run down to 80HZ, as this is somewhat of a standard in movie encoding.
"...I have the 60's in my HT setup, and heard a definite improvement when I switched the setting TO "large" vs "small"...." (tonyp54)
Might I comment here?...MOST PEOPLE will be getting enitially better bass response (at lest for music), and seem to be getting flatter, more cohesive, better balanced bass by running thier "floorstanding speakers" as "large" or full range from their setup! Why? It's any easy answer from my experiences over the years. ff
First, most people don't have smaller speakers setup for good bass response at the CRITICAL CROSSOVER REIGION (usually 80hz as "small"), as welll as for the subwoofer's crossover and volume setting, and thus get that "hole in the middle" and lack of upper/mid bass and dynamics! Most 8' ceiling applications need 24" stand heights for good bass response in smaller rooms I've found. And it's real easy to get soft bass in that reigion on "too high" of a stand placment. Floor standers already have the bass woofers and/or port down lower to the floor boundary, and thus are DESIGNED to balance better that way from the start. Too many people don't know how to get good bass resonse from small speakers. They place them where THEY THINK THEY SHOULD GO, and think that that's as good as it gets!.....HARDLY!!!
The key to any speakers great sound is speaker/seating location (location, location, location), setup, and acoustics! These things, most all people know NOTHING ABOUT! Thus, their system sounds cruddy no matter what they got...the truth.
Basically, big speakers at least sound like they have tighter more well integrated bass response without much help. Of course, they'll still sound boomy if you don't place them right either. However, MORE PEOPLE get boomy, too loud, one-notey, poorly integrated, and improperly leveled and placed bsss response from A SUBWOOFER AS WELL!
You put that all together, and it's no wonder many people want to play their speakers full range with no sub!!! I got news for ya, IT'S USER ERROR!!!!..and lack of knowledge/experience...garanteed.
Anyway, that's where the advantage ends. Playing a full range typical passive speaker as large is dynamically limiting your movie and more dynamic music playback dramatically!!! Passive speakers will EASILY bottom out, clip, blow tweeters, distort woofers, and sound dynamically strained, flat, and powerless when you feed em the wrong material! Cross over this same speaker (or a smaller monitor) as "small", let the MUCH MORE ABLE powered subwoofer handle the bass bellow that, and you're systems dynamics will go through the roof!!!...much more powerful, and able to handle big dynamics with ease!!
Just pop in any DTS blockbuster this way, or even some hard driving techno, rock, or heavy percussion music, and you'll immediately see how much more efficient and dynamic your sytem is!
Hey, lucas Film THX didn't spend 100's of thousands of hours coming up with these specs for nothing!..they work!!!
Even big commercial theaters cross over at 80hz to powered subwoofers!...and those big horns with 15" woofers are like 118db sensitive at 1/m watt!!!! Typical full range home monitors are like 88db or so only!!...hardly dynamically efficient.
Hey I've worked in 6 audio stores, hooked up hundreds of systems, and designed and engineered HT's for a living for years now. I've tried it all at least a few times over the years. You NEED to get active "more efficient" drivers involved with the heavy bass dubties for best control and dyanmic abilities from a system some how! Most passive speaekrs need major help. Crossing over as "small" helps make the monitors and amp combo run much more efficiently with more contorl, and let's the powered subs handle the demanding bass. (also, many people "under-sub" their rooms, and often need more woofers!... In such cases, often you'll be getting more bass overal when you, yes, run your larger speakers as "large". However, it's still better to add more well placed powered subs instead.)
Only situations I've personally encountered, where it works in a home setup to run speakes as "large", is either when your speakers have "active subs" built in, or you're using ultra high efficient speakers, like big horn models. And even then, I still find a powered sub crossed over high enough has strong dynamic advantages there as well, just like the movie theaters use.
I urge everyone to experiment with speaker placement for best bass response and coupling from EVERY SPEAKER from the seating possition(s) before doing ANYTHING ELSE!!!...that includes subs. Most don't do this, and it's simply easier to run speakers as "large", because they didn't first like the results they got froma poor initial setup!....
I use my audio system for stereo music and well as 5.1 movies and HDTV.
I had been using KEF 102/2 monitors, a KEF 100 C, with a Velodyne HGS-10, and noticed the KEFS were more open and transparent with a larger and more precise soundstage when the Proceed processor was set to deliver below 80 Hz to the sub.
I substituted floor standing KEF 104/2s and a KEF 200 C, and I reset the processor to treat the LR speakers as large. But when a system integrator who is very familiar with high-end audio delivered a Velodyne HGS-15, he recommended resetting the processor to deliver everything below 80 Hz to the sub. I was surprised to discover the same effect on transparency and soundstage, even with the much larger speakers.
The HGS-15 integrates seamlessly with the KEF 104/2s, and I'm unaware of a crossover. I'm only aware of the sub when I realize most speakers can't reproduce pipe organ pedal notes with such authority, including that subtle vibration you experience when you hear a pipe organ live.
Based on my limited experience, I'd recommend turning over LFE duty to a good sub.