LS50 + Sub Or Floorstander?

If you stay with stand mounts, I'd suggest you can do better than the Kefs. Specifically Monitor Audio Silver 100s.

You can be successful either way. I think a main goal with adding a subwoofer is to even out the bass response. To do this you have to solve the room modes and the bass response of the the LS50 at the same time. There are additional tools like EQ, phase, volume, crossovers and multiple subs that aides in playing at-home speaker designer, but you need be lucky and/or good to do it. I agree with hilde45 that in room measurements are way more efficient and accurate than listening. Though floor standers do not have the same latitude for adjustments as subs, you get to skip the headache of playing speaker designer and get a sound with larger scale. I state this based on my run through the subwoofer gauntlet with both REL and JL, using both small and larger speakers. I am definitely not an expert, though.   REL offers a 60-day return. If you go that route, set them up ASAP. 60 days goes by fast. 

I was/am in the same boat, trying to match a sub to 2 monitors.

It really depends on your music choices, 4 out 5 times, my subwoofer doesn't add much to the overall sound quality and image

Floorstanders.  

I had the LS50s and subwoofers and the issue was there was punch impact missing in the 80 to 100 hz range that sounds best covered by the main speaker.  

Also i have had subs in and out of several systems and even the best of them slow down the microdynamics and speed of the main speakers.  

currently running spendor D7.2 floorstanders without subwoofers and do not need or miss them. 

Floorstanders that have excellent sound and bass in your budget include Elac Carina, PSB Imagine X2T, vandersteen 2ce and Elac Solano. 

Thanks for the input and the suggestions. Unfortunately, many speakers that I’m certain would solve all of my problems—LS60, Kef Reference Three—will have to remain the stuff that dreams are made of. 

If money allows it, towers with subs can't be beat imo. I got very big PBN MONTANA XPS speakers with dual 10" woofers and I still would not part with my dual Rythmick F12 subs. It's not that these large towers don"t have enough bass, it's more how much more they open up at all frequencies when backed up by the subs. 

Yup sdding a sub(s) even if you go the floor standing speaker route adds so much. 

@paul6001 

The LS50’s are great under the right circumstances, but a sub or two will take them to a whole new level! Check out KEF’s KC62.  They really play well together. 
The next step up is to sell the LS50’s and get into the R series. The R5’s are around $2600 a pair (not on sale) with a Sub or two.

All the best.

The LS50  is agreat speaker. Getting 2 subs lets you position the subs where they sound best which is often not where the main speakers are. But I advise getting subs with a built in high pass filter(not all do). That takes a huge load off the main speaker allowing them to be more dynamic and probably give you along with the improved bass the large scale sound you said you wanted.

If you can afford them try Audio Physic Tempo 35.

If you like the sonic signature, why not demo the LS60 and see if they are to your liking? They are stunning to look at, and are getting some pretty great reviews

We are a kef dealer thela 50 metas do sound amazing for their size however a small monitor will alwayways sound small adding a subwoofer won't help

a good subwoofer simply adds pressure to the leading and trailing edges of what the monitor is doing

we often played the ls 50 and then demoed the r series floorstanders and the floor standers always sounded better

if you can swing it a pair of reference three kefs is really the way to go

and many dealers are selling the older non metas at a great price

Dave and Troy

audio intellect NJ

Kef dealer

The monitor needs to be able to play with authority from 70-80hz on up to have that full visceral sound even with a sub. If it can do that at the volumes you are looking for then I think you are good to go. Probably need some kind of crossover to keep the deep bass out of the KEF unless it’s always low volumes. 

A lot depends on your room’s acoustics. Your room is 15x20 with what ceiling height?

I have read, repeatedly, that even floorstanders benefit from subs, not least because they can be positioned in places other than where the floorstanders are.

To put the point otherwise, if you’re seeking good bass in your room, the first step is to know what your room is like, from the perspective of bass. AMROC can help, and so can a microphone and some positioning experiments.

If you don’t wish to investigate your room’s characteristics, you are effectively deciding to experiment without guardrails. If that’s fun for you, go for it! But know that’s what you’re doing.

I'd probably side with small floorstanders for the sense of scale, especially in a room of your size (and I've heard LS50s several times). You may not get as deep bass as a  separate sub, but many great 2.5 or 3 way designs have in-room performance rather low and a good sense of body, or of a larger sized speaker-I get it.

My 2.5 way speakers manage solid in-room to 31Hz with two 4.5" mid/woofers and ports, in a 17x21x10 room with openings. Small floorstanders, well-designed can accomplish a lot of most musical requirements, IMO.

I should have also mentioned the new Baby Blade, KEF LS60. Sell all your gear and just plug these 2 speakers into a wall outlet. Done.

Subs will make a big improvement but the LS50 is still a small speaker in the range the subs don’t cover. Plus a couple subs that match the quality of the LS50 are expensive and require a crossover frequency that is higher than optimal. Personally I prefer standmounts that go low enough in the bass or floorstanders.

I had the LS50 for a decade and recently got the LS50 Meta. What a speaker, so much better than the LS50. More clarity, detail. and the speaker disappears better. I have it hooked up to KEF KC62 sub which I have raised off the floor on a bar stool. Now I have not compared it to the sub on the floor. It sounds too good, and I am lazy to do so.

My room is not too big, 12x 11 x 9. I think this is the ideal sized room for the LS50. I had the Thiel CS3.7 in this same room before the LS50 Meta, The Meta is a much better fit in this room. I did have the CS3.7 working fatigue free in the room. The smaller Meta + sub just fits and sounds better in this space.

I was going to get the Yamaha NS3000 monitor from Canada because I love the bigger NS5000. The NS3000 is about $9K USD. I got the LS50 Meta first because the old LS50 got damaged, and I always want a LS50 around. 

The level of quality I heard on the LS50 Meta + KC62 sub made me forget about buying anything else for this room.

The only time I was disappointed with the LS50 Meta was one day when I listened the whole day while working deep on a project. At the end of the day, I was thinking the magic is gone with the LS50 Meta. Maybe I need to revisit the NS3000 idea, I found out that I had turned off the sub the prior night when I was listening to some headphones on my 2-channel gear. Turned the sub back on (wirelessly) and the magic was back.

Do not let the relatively low-cost fool you. The LS50 Meta and KC62 sub in a small room is reference level sound. I use Benchmark AHB2 monos on the speakers.

Currently own Blades, mainly bc 5 yrs ago I owned the Ref 1, the good ones that are $6k ish. They’re smallish but they bring the thunder. And of course you maintain the uni-q coherency. Nothing like them.

Well tannoy & fyne mebbe. I owned fyne 501 last yr, & my buddies didn't believe their eyes or ears when I played them. 

In one of my setups I've gone through KEF LS50s, LS50 Metas, and then to reduce clutter LS50 Wireless IIs, all with a pair of KEF KC62 subs.  In each case, large orchestrations were presented with a satisfying sense of scale made possible by the subs.  In another setup, KEF Reference 1s are augmented by a pair of Velodyne HGS-15s, and again it's the subs that make large orchestrations scale.

I like having the sub separate because you can place it in the room where it performs best. Kef makes nice subs too.