You want to match your front three. It is always best to have all 5 be in the same line, but front three are most critical as they are truly blending sound.

Regarding the subwoofer, I feel like it is expensive for the specs it provides. Is this just for home theatre? If you are interested in using this for music, I would seriously consider Sunfire Subs. The SDS-12 line will deliver more punch with similar detail to the Kef at $599. The HRS - 10 will deliver far more punch and way more detail for $950. You should also seriously consider the NHT B-10 or B-12d. They will both outperform the Kef for detail and punch.

Good luck

No question 3 LS50s would be my first choice, especially for home theatre. The level of detail is exceptional, which is very important for home theatre performance.

In order:

1) 3 LS50s
2) 2 R100s + R200c

I don't think mixing and matching these two speaker lines is wise. Despite being from the same manufacturer with similar pricing, they sound more different than you would think.

In fairness though, I am a touch biased in that when I demo'd the Kef's, I listened side by side with Sunfire speakers that were a particularly strong value and the B&W CM line which I just preferred.

The only way to judge is to listen to them yourself if you can before you buy. Just because I like the LS50s better than the R100s doesn't mean you will.

And your points are why I wanted to caveat my personal bias against the Kef R line. Compared to other speakers that are between $900 and $1500, I was unimpressed and I personally don't like the way they sound. I feel the R100s lack clarity and detail compared to its peers and found it a bit fatiguing.

Alternatively, the LS50 sounded remarkably clear with a tremendous level of detail rivaling any speaker I listened to under $3000. That level of detail is why I cite them as very appealing for home theatre but I have never heard them in a multichannel environment, only in 2 channel. And can't honestly say that an LS50 would do a good or bad job as a center channel.

One thing to consider, and I don't remember testing this when I demo'd the LS50s is how do they sound off axis? Only 1 person will be in the sweet spot while watching a movie and the balance of viewers will be listening off axis. If the LS50s don't do a good job off axis, that would make it a particularly bad center channel. I do not know the answer to this.

That being said, I can confidently say those two lines sound dramatically different and I can't imagine a scenario where I would mix the two speakers together.

I know you have the Kef Q surrounds but since they aren't going to match the Rs or the LS50 in tone anyway, have you considered another manufacturer?

Kef Direct is selling single LS50s for a $50 up charge for use as a center channel, at least in the US and Canada. Everything I have read suggests that using a 3rd LS50 for a center channel should work really well.

I saw the same feedback regarding how tough it is to blend a sub with the LS50s due to how crisp and detailed they are. When time comes, I would look for a high powered, sealed subwoofer. That is the only way to get the level of detail you are going to want to blend with those Kefs while delivering the big sound you want with home theatre. For value, the Sunfire HRS line and the NHT B12d are the best products for the money you will find. if they are available in your country, I would look at them first.

I have an HRS 12 in my home theatre. There is a reason why it is benchmarked against the JL Audio Fathoms in reviews. For 1/3 of the price, it sounds closer than you would think and is a much fairer comparison than I would have expected. The NHT is super detailed but has 1/2 the power of the Sunfire HRS and goes to 27hz vs 16hz.

> Kef R100 or LS50 as FRONT?

It would be a mistake to use either. The LS50 is a desk speaker or near field monitor that you listen to over short distances. Something that sits part way between headphones and main room speakers. It cannot cleanly reproduced the required SPL of a main speaker because the midwoofer cone has the area of a 4" and, to make matters worse, the coaxial arrangement means that if you ask the midrange cone to move significantly it will knacker the tweeter's output by moving it's waveguide around and creating intermodulation distortion. A similar argument applies to the R100.

The R300 is a nice speaker and better suited to the role of main speaker. The woofer crosses to the coaxial midrange at 500 Hz which greatly reduces the required deflection of the coaxial midrange cone.

theviethd wrote:

You are right. What I read on forum, be true that LS50 is so effective & better performance in small space (small - medium room). My listening room can meet this criteria.

If you don't want to take advice from an unknown poster on a forum, which is probably wise, and you are buying from a dealer then ask him. In the unlikely event he says the LS50 is able to function as main speakers then ask for a demonstration at standard levels (i.e. the level in a cinema and the level music starts to sound right). It is not that these tiny speakers cannot play loud and clean but that they they cannot handle transients cleanly at the standard level. They should be fine playing quietly but is that all you require?

Whatever, it is your money to do with as you please and I will spare you labouring the point further.

Two thoughts: You have the Monitor Audio Silver 2's currently. The LS50s are a very good speaker but they aren't going to be a huge leap forward from the Silver 2s. You will get more transparency but less bass.

Check the specs, everal things will be different. First, the Kef LS50s are spec'd to go to 79hz at -3db and 47hz at -6hz. Having listened to them, they don't deliver a ton off bass. The silver 2s are spec'd to go to 60hz at -3db and I don't see a -6 db spec for them. That being said, having listened to the Silver 2s, they deliver noticeably more bass than the Kefs.

Second, the Kefs are less efficient at 85dB vs 87dB on the Silver 2s. Thus, you will find that to deliver the same volume as the Monitor Audio's, you will need to turn the volume up. That being said, 50w of power to the LS50s will deliver 99.2db of volume at 3M. That would be uncomfortably loud.

In a big room, the LS50s would be unable to deliver the required volume. You are in a small room that those speakers can fill it with sound They are much less sensitive than many speakers on the market, but I have never heard that they are only suited as desk top speakers and will only perform at low levels. Although I don't own them, I spent about two hours demo'ing them in a custom installers listing room and that is not consistent with my own experience. Admittedly, they were well broken in with installer estimating 500 hours of listening time and they were being driven by Bryston equipment, but they sounded really good when the volume was turned up.

As I type this, I am siting in a room that is slightly larger than yours, listening the the Revel Perroma3 M105s which have an 86dB sensitivity being driven by a 50w amp. I achieve reference levels at about 1/2 way on my volume dial. If I go much beyond that, output becomes uncomfortably loud. Which makes sense since at 4 meters, a speaker with an 86dB sensitivity can output 94.7dB at 25w. For comparisons sake, the 85dB Kef LS 50s would output 93.7dB of power in the exact same spot.

You may find that your Yamaha receiver is not up to the task as the Kefs are way, way less forgiving than the Monitor Audio's. If at all possible, I would try and make sure that the speakers are returnable. Like anything, when you get a speaker in your listening room, you may be unhappy with them. I spent extra to get my Revels directly from Harman audio so that I could return them if I was unhappy. Coincidentally, my second choice was the LS50s and if I was unhappy with the Revels, I intended to return them and get the Kefs. That being said, the only way to really know is to get them in your home and listen to them.

bierfeldt wrote:

Second, the Kefs are less efficient at 85dB vs 87dB on the Silver 2s. Thus, you will find that to deliver the same volume as the Monitor Audio's, you will need to turn the volume up. That being said, 50w of power to the LS50s will deliver 99.2db of volume at 3M. That would be uncomfortably loud.

It is good to see analysis but I think you are missing a number of factors. Firstly, if you want the music to be clean the speaker must reproduced the peaks undistorted not just the average. Reasonable headroom for the peaks is +20dB. Some music has peaks greater than this but not often and, of course, some horrible modern compressed stuff will probably fit in +10dB.

Secondly you need to know the linear limit of the driver because it is likely to be this that is going to be limit rather than the power at low frequencies. Here is some information on the R series coaxial:

http://medleysmusings.com/kef-r300-midrange-drive-unit-testing/

and here is a free program that will help with plotting the various limits:

http://www.linearteam.dk/default.aspx?pageid=winisdpro

but if you have become familiar with an alternative as part of your DIY speaker interest then please use that.

When a speaker is asked to play peaks that are beyond it's capability it will start to sound less clear and louder.

The Medley Musings is intersesting. I am not going to pretend to suggest that I understand these measurements completely, but the performance between the R300 and LS50 drivers seemed similar though the LS50 tests weren't as extensive.

It seems like the LS50 underperformed the R300 by a small amount on high pitches and generally had a reduced output but there was a caveat that because the driver wasn't flush mount, that would cause a drop off in performance at high pitches. How much of that distortion is being caused by the driver vs the mounting is not clarified. Otherwise, response and distortion measures are flat, even at 90 and 96dB.

What was interesting to me was the significant drop off at 30 degrees. That would make me question whether this speaker should be used for a center channel given the typical layout of a theatre room. Am I even close to interpreting these results correctly or am I completely wrong. It would not shock me if I was wrong as I am far from technically savvy.

I hadn't realised Erin had measured the LS50 driver so thanks for that. Were you to continue your analysis, it should improve confidence in the frequency dependent degree to which the peaks in the music would be squashed were the tiny LS50 to be used as main speakers when playing at the standard SPL level.

The exposed sharp edges due to not flush mounting the driver will cause significant amounts of ring shaped diffraction. This will interfere significantly with the main driver radiation directly on axis causing the high frequency response to be lumpy as can be seen. It will have less effect off axis again as can be seen. It will not affect the THD plots.

The off axis response of the coaxial is probably the strongest benefit compared to a speaker with non-coaxial drivers. You can see this in the off axis measurements in the Stereophile review despite them being presented in an almost unreadable form.

A coaxial 3 is generally good thing to use for a centre because the alternative is putting a tweeter above a midrange with the woofers to the sides. The coaxial will not only enable the height to be reduced but it will also provide a waveguide action on the tweeter to even out the radiation pattern.

I went through the same exercise. initially I purchased two sets of LS50s as I could not purchase individual speakers and experimented with a 3 L/C/R LS50 setup. To be honest I didn't like the LS50 in a centre speaker role, because I felt it did not have enough heft for movie soundtracks and it sounded a bit thin and restrictive. I reverted to using the set as front L/R and surround L/R and used a phantom centre channel. I ended up purchasing a KEF R200c and have been happy with the sound. Vocal clarity is excellent and has more presence, while there is some slight tonal mismatching its not easy to spot and doesn't in my view detract from the overall sound, even with my multi-channel music disks.

I listened to the R300 in the store where I purchased the R200c and still preferred the sound of the LS50, but the R300 does have a lot more bass and presence, but I didn't particularly like its more laid back character and the sound of the bass driver. Its a nice option for people who prefer a more floor standing like presentation without sacrificing the imaging and staging of a bookshelf. The strong point of the LS50 is clarity, speed and coherence. If I were to upgrade I'd probably look in the direction of the KEF R500. Hoop you find something that works for you! The LS50s are brilliant little speakers.

daerron wrote:

I reverted to using the set as front L/R and surround L/R and used a phantom centre channel.

In this configuration did the main speakers sound clean at standard cinema sound levels? And with the centre?

andy_ wrote:

daerron wrote:

I reverted to using the set as front L/R and surround L/R and used a phantom centre channel.

In this configuration did the main speakers sound clean at standard cinema sound levels? And with the centre?

I normally don't listen at reference levels, but I did give the system a thorough working over with the pod racer scene in Star Wars Phantom Menace and if you use a good quality subwoofer and use a crossover of 80-90Hz then they handle it pretty well. The LS50 actually has the sound staging to pull off a phantom channel quite commendably. My journey to the LS50s ended up from having the B&W CM9 and CMC2 pairing prior to that. The CM9 and CMC2 were pretty massive as far as a front stage goes, though I disliked the way the CM9s muddied up the dialogue. Going to the LS50s was always going to be quite a step down in terms of scale and slam, but I prefer the clarity and precision of the effects.

theviethd wrote:

How is yr room size that 3 LS50 could not perform as good as many rated with single LS50 as center channel ?

My listening room is 172 feet (approximately 16 square meter) : 12 inch * 14 inch (W * D)

How is the comparision ratio of 3LS50 (front channel) & LS50 (FL/FR) + R200C ? like 7/10 or 8/10 lean to L200C as center ?

As yr saying, LS50 for front & R200C as center, is very good. Actually, I havent heard LS50 as not any audio store in my area distributing. But did listen R200C - be great with clean, detail & forward sound stage (compare with my memory of IQ60C at home)

Yr setup (2LS50 + R200C, always be in my mind). These be worth for high consideration.

My room is 18 x 22 ft so I guess its small to medium in size. As I mentioned in my previous post the LCR pairing I was using before that was a B&W CM9 and CMC2 and the three speakers together combined to create a wall of sound that was excellent with movies. So it might entirely have to do with expectation. When I put the LS50 in the centre it suddenly felt like the stage lacked presence and it felt strange having the effects and dialogue coming from a 5-1/4 inch speaker. It just felt very noticeable vs how the CMC2 disappeared. Maybe my Yamaha RX-A3010 mucked up the auto-EQ?.I definitely preferred the phantom channel.

As so much of a movie soundtrack actually goes through the centre channel I wanted to look at a speaker designed specifically for this purpose even though it meant making a sacrifice in terms of tonal matching. The R200C certainly disappears between the LS50s which is exactly what I wanted it to do and personally I don't find the tonal mismatch very noticeable. At times I think I should have gone for the R600C to get a bit more scale, but I guess it would dominate the left and right channels.

daerron wrote:

The CM9 and CMC2 were pretty massive as far as a front stage goes, though I disliked the way the CM9s muddied up the dialogue. Going to the LS50s was always going to be quite a step down in terms of scale and slam, but I prefer the clarity and precision of the effects.

Not sure I wholly understand scale and slam but it sounds a bit like it might be an absence of suppressing peaks in the music. The large midrange crossed high to a flush mounted tweeter is going to add a character to the sound despite the on axis "voicing" you can see in the Stereophile reviews. I don't know why B&W do this but I guess it makes it a B&W speaker and they seem to be making a success of it.

I assume the clarity and precision are at quieter levels than the standard level. I can well believe the good off axis behaviour of the LS50 compared to the B&W interacts better with the room to improve the clarity of speech in stereo. I would expect it to be less marked with more channels. Although how lively is the room - large curtains, bookcases, furniture, acoustic panels?

Was the move from the CM9s to LS50 forced by circumstances to some extent or wholly voluntary? As you may have guessed from my first post I find it interesting that an enthusiast would opt for main speakers that are too small by conventional reasoning.

andy_ wrote:

Not sure I wholly understand scale and slam but it sounds a bit like it might be an absence of suppressing peaks in the music. The large midrange crossed high to a flush mounted tweeter is going to add a character to the sound despite the on axis "voicing" you can see in the Stereophile reviews. I don't know why B&W do this but I guess it makes it a B&W speaker and they seem to be making a success of it.

I assume the clarity and precision are at quieter levels than the standard level. I can well believe the good off axis behaviour of the LS50 compared to the B&W interacts better with the room to improve the clarity of speech in stereo. I would expect it to be less marked with more channels. Although how lively is the room - large curtains, bookcases, furniture, acoustic panels?

Was the move from the CM9s to LS50 forced by circumstances to some extent or wholly voluntary? As you may have guessed from my first post I find it interesting that an enthusiast would opt for main speakers that are too small by conventional reasoning.

Its just a question of heft or ability to move air which allows it to belt out soundtracks. The LS50s of course are much smaller and never expected them to match the CM9s on that front. I made the change because I moved into a smaller house and I developed a dislike in the CM9s performance with stereo music. I had bookshelf speakers prior to the CM9s and prefer the imaging and staging of a good bookshelf. Of course demo'ing the LS50s sold me on them instantly. My current listening is fully carpeted, heavy curtains on one side and lots of furniture, though I do get a bit of an echo off the ceiling. I vastly prefer the LS50 with subwoofers compared to the B&W CM9. The subwoofer I'm using has a decent built in EQ and is sealed so it handles frequencies well up to 100Hz.

daerron wrote:

Its just a question of heft or ability to move air which allows it to belt out soundtracks. The LS50s of course are much smaller and never expected them to match the CM9s on that front. I made the change because I moved into a smaller house and I developed a dislike in the CM9s performance with stereo music. I had bookshelf speakers prior to the CM9s and prefer the imaging and staging of a good bookshelf. Of course demo'ing the LS50s sold me on them instantly. My current listening is fully carpeted, heavy curtains on one side and lots of furniture, though I do get a bit of an echo off the ceiling. I vastly prefer the LS50 with subwoofers compared to the B&W CM9. The subwoofer I'm using has a decent built in EQ and is sealed so it handles frequencies well up to 100Hz.

Thanks for the reply. It is interesting how enthusiasts can weight their requirements quite so differently. I still find it a bit odd that the SPL limits of a desk speaker would be accepted for main speakers but this would clearly seem to be the case.

I'm using a Velodyne SPL 1200 Ultra or the Optimum 12 as its called in the US. The built-in EQ system, though basic, does the job reasonably well and its fast enough to keep up. You have to use a fast and accurate sub with the LS50s otherwise it will smear the sound. I haven't heard the REL subs, but have read that the T9 was pretty good, but you will have to find somebody who owns one to get their opinion. I would probably buy a subwoofer internet direct as they offer so much extra value for money or build my own subs.

An upgrade to the Yamaha RX-A1040 would also be good, I'm using the Yamaha RX-A3010 in my setup and the processing is excellent. I also have them hooked up to an external five channel power amplifier (5x150W) which I originally used with the B&W speakers, but its not really needed with the smaller KEFs but they do like quality amplification very much.

theviethd wrote:

But as yr saying & also same with what I read, matching with LS50, should be a good sub (sealed typpe), strong power, fast & accurate, should be 10" drive.

My narrow list is Rel T7 (reasonable cost) or Rel R218 (if can afford)

If you like REL but cost is a concern then this may be of interest:

http://www.bkelec.com/HiFi/Sub_Woofers.htm

I believe they are, or have been, the manufacturer of REL subwoofers among others. Comparing the parts and prices may be of interest.