KEF LS50 Bookshelf Speaker Review

[SKBubba]

Fun trivia. We were down in Muscle Shoals and toured Fame Studios. In Studio A they had a pair of these to demo some of the tracks recorded there. They sounded OK but the room was too big for them.

They were sitting on top of a big ass pair of Altec (maybe? no markings) horn speakers. I wanted to hear those but the tour guide said they were complicated to get dialed up and besides he couldn't go in the control room to do it because there were people in there working to set up for an afternoon session.

More trivia: Muscle Shoals Sound Studio (started by Fame's former session players) is not in Muscle Shoals. It's in Sheffield.

 

[pbc]

I've been eyeing the LS50's as I love the look. I have an SVS SB13-Ultra sealed sub for low end duties, and an SMSL AO200 for an amp which also has a subwoofer out. I've never used a 2.1 system like this before outside of receivers, which have built in crossovers to roll off mains at 80hz/100hz or whatever and send the rest to the subwoofer, this way not straining the speakers.

How would that work in this sort of system as the SMSL AO200 does not seem to have any form of cross over?

 

[phoenixdogfan]

Check you manual on the SVS. I have an SB 2000 and it has a low pass for the sub as well as a 12db/oct 80hz high pass. If you have that, just send L-R preamp output to the SVS, set the low pass for 60-80 hz, play with the sub gain, sub position, and phase until it sound right and send the L-R (high pass output) from the sub to your power amp and you will be in business.

 

[peng]

I've been eyeing the LS50's as I love the look. I have an SVS SB13-Ultra sealed sub for low end duties, and an SMSL AO200 for an amp which also has a subwoofer out. I've never used a 2.1 system like this before outside of receivers, which have built in crossovers to roll off mains at 80hz/100hz or whatever and send the rest to the subwoofer, this way not straining the speakers.

How would that work in this sort of system as the SMSL AO200 does not seem to have any form of cross over?

It can work fine if you don't need a lot of spl and set the XO to 100 Hz, not 80 Hz. When I used my LS50 with my 15 in sealed Rythmik E15HP, I found 90 Hz XC okay but 100 Hz better.

Found one of the REW graphs I plotted to compare the combined effects with XT32 vs minidsp/REW:

Either way, bass response could definitely be improved with a sub but without room correction it will be his and miss depending on your room. I have since demoted the LS50 for desktop duties and with Dirac Live I don't feel the need for a subwoofer at all.

Found one that was without using room correction:

 

[Descartes]

It can work fine if you don't need a lot of spl and set the XO to 100 Hz, not 80 Hz. When I used my LS50 with my 15 in sealed Rythmik E15HP, I found 90 Hz XC okay but 100 Hz better.

Found one of the REW graphs I plotted to compare the combined effects with XT32 vs minidsp/REW:

Either way, bass response could definitely be improved with a sub but without room correction it will be his and miss depending on your room. I have since demoted the LS50 for desktop duties and with Dirac Live I don't feel the need for a subwoofer at all.

View attachment 243114

Found one that was without using room correction:

View attachment 243141

I have two 15” subs so bass is good

 

[pbc]

It can work fine if you don't need a lot of spl and set the XO to 100 Hz, not 80 Hz. When I used my LS50 with my 15 in sealed Rythmik E15HP, I found 90 Hz XC okay but 100 Hz better.

Found one of the REW graphs I plotted to compare the combined effects with XT32 vs minidsp/REW:

Either way, bass response could definitely be improved with a sub but without room correction it will be his and miss depending on your room. I have since demoted the LS50 for desktop duties and with Dirac Live I don't feel the need for a subwoofer at all.

View attachment 243114

Found one that was without using room correction:

View attachment 243141

Thanks, presumably I can use the older balanced MiniDSP 2x4 I have to put in a high pass at 100hz for the LS50's and a corresponding low pass to the sub (though the unit came with funky phoenix connectors that I've never really looked at to see whether I can find the RCA equivalents).

In the short term I will be using an older Sonos Connect amp,. Would I be connecting via the analog RCA connectors on the Sonos connect directly to the phoenix on the MiniDSP...and then from the MiniDSP Output 1 and 2 directly to the speakers and say output 3 to the sub?

 

[ethernode]

Hi everyone.

For the record, just acquired these for 380€ new (in france). Running with a Aiyima A07, MiniDSP 2x4 (currently playing with crossover around 100-120 Hz) and an SVS-SB1000 behind an antimode 8033 for bass DRC.

Do you think that upgrading the amp with an NCore amp will make an actual audible difference (i read about the TPA3255 load-induced non-linearities) ; also wondering whether EQ could fix this non-linearity as well as the LS50 brightness and bass drop...

If anyone has feedback, i'd love to hear it !

 

[TheBatsEar]

Nice stuff

Do you think that upgrading the amp with an NCore amp will make an actual audible difference

Unless you listen at the power limit of the Aiyima, i don't think so.

BTW, i have similar setup which is getting prepared as a gift: Aiyima A07, MiniDSP 2.4HD, two low end Elac subs and a a pair of Elac DBR62. It's really fun and really good.

I had the LS50 Meta (sold) and have the LS50 (wanted to sell them for 600€, no chance now). They are cool. I would say the higher you can cut the LS50 off, the better, it means less power is needed from the amp and reducing bass load on the LS50 is always a good idea. If your sub is in the middle, i would even try to go to 120 or 130.

Do you have a measurement microphone?

 

[ethernode]

Mic : yes (berhringer, still not had the time to run sweeps yet). Cool gift you are preparing !

Interesting, you sold the metas but kept the original LS50, why ? I tried the DBR62 but found them too recessed to my taste and I never got to get a good image in my room. LS50s seem better to me for now, even if my old Wharfedale Evo 8 are creating a much, much wider / airier soundstage -- I don't understand why yet.

I'm not sure that it's a clipping problem: according to the link above the A07 has frequency response variations depending on load (even at normal volume i believe), which applies some boost on high frequencies around 3khz depending on the impedence -- something not flat at all on LS50s, which would make LS50 a pretty bad matching amp for the A07.

Sub is not in the middle for now but it's not really localisable either to my ears.

 

[ethernode]

Hi,

@thewas_ asked me to have a look at his EQ and run my optimizer.
here are the results:
Score with No EQ: 4.6
For AB comparison the EQed version need to be boosted and the LF Boost may result in a reduced dynamic range.

The initial fitting by @thewas_ is pretty good.
Only minor changes after the optimization resulting a slightly higher score.
Mostly due to smoother PIR and ON which is not easy to do by hand.
the Final gain no EQ vs Optimized EQ is quite decent.

TheWas_ EQ:
Score: 6.16

Type      Freq      Gain     Q
PEQ       67.2,     3.00,   2.00,...
PEQ      170.0,    -2.00,   1.00,...
PEQ      540.0,     1.60,   5.00,...
PEQ      830.0,    -2.40,   2.50,...
PEQ     1240.0,    -1.20,   8.00,...
PEQ     1650.0,     2.50,   3.00,...
PEQ     2640.0,    -2.80,   2.00,...
PEQ     4620.0,    -3.40,   3.00,...

Score after Optimization: 6.36

Type      Freq      Gain     Q
PEQ       65.0,     3.00,   1.78,...
PEQ      166.5,    -2.10,   0.88,...
PEQ      550.0,     1.40,   3.72,...
PEQ      830.0,    -2.40,   1.83,...
PEQ     1224.0,    -1.34,   9.45,...
PEQ     1609.0,     2.11,   2.65,...
PEQ     2764.0,    -2.80,   1.35,...
PEQ     4747.0,    -3.40,   3.00,...

EQ designView attachment 84181


View attachment 84182View attachment 84180View attachment 84177View attachment 84178View attachment 84179
No EQ vs Optimized
View attachment 84176

Hi there,

I own a minidsp 2x4 (non HD) that only has 5 band EQ capability. Which filters should I skip in your opinion to go from your 8 filters (I use a sub crossed around 90 so I picked the filters by descending frequency as a random guess) ?

Anyone else tried to EQ the LS50 with the 2x4 ?

 

[Maiky76]

Hi there,

I own a minidsp 2x4 (non HD) that only has 5 band EQ capability. Which filters should I skip in your opinion to go from your 8 filters (I use a sub crossed around 90 so I picked the filters by descending frequency as a random guess) ?

Anyone else tried to EQ the LS50 with the 2x4 ?

Hi,

I think it's 6BQ not 5 but whatever...
I don't know which the plugin you are using, anyways, you can split the EQ and distribute it over two blocks in both cases:
Links to the specsheets:

https://www.minidsp.com/images/documents/Product%20Brief-%202way%20Xover%2021%20ADV%20plug-in.pdf

https://www.minidsp.com/images/documents/Product%20Brief-%202way%20Xover%20ADV%20plug-in.pdf

2.1 case

2x4 case

Assuming you want to keep the 6 Biquads BEFORE the Crossover for Bass EQ/Room integration (which you should be doing too) and that you kept the passive Xover in the LS50 and therefore using a single channel from the MiniDSP to apply the EQ (in 2x2 configuration i.e. both Tweeters paths are unused for example in the 2x4 ), I have devised 2 ways to proceed. There may be others but I don't know your system structure...

Note that you may have to use the Advance setting in the Crossover block in order to program the correct coefficients to set the rest of the Xover block to "by-pass" you'll need to copy and past in the right block. REW can do the calculation (sampling rate is 48kHz) and the export in the correct format for you.
The PEQ/6 Biquad block should be filled by just entering the values I shared without the need for advance mode, but I might be wrong...
There plenty of tutorials on the web or even on Youtube...

Equaliser Selection

"The miniDSP equaliser setting supports the same filter types and resolutions as the Generic setting, but for 6 filters operating at 48 kHz. It is aimed at the miniDSP plug-in Advanced mode, which allows filters to be specified by their biquad coefficients. The Save Filter Coefficients to File action writes the filter coefficients to a file in a format suitable for use with the miniDSP software (note that the a1 and a2 coefficients are negated per the miniDSP format). An advantage of this is the very high filter frequency and Q resolution it allows, permitting exact targeting of modal resonances. The miniDSP plug-in has an Import REW File button on its Parametric EQ configuration screens to load the files."

And there

REW AutoEQ step by step

miniDSP is a leading manufacturer of Digital Audio Signal Processors for the HomeTheater, Hifi, headphone and Automotive market. Join our large community of Audiophiles, Engineers and DIYers using our innovative products.

www.minidsp.com

Score EQ, no Highpass filter enabled:

February202023-114538

Preamp: -2.6 dB

Filter 1: ON PK Fc 65.00,    3.00,    1.78 -> goes to 2way Xover block
Filter 2: ON PK Fc 166.50,    -2.10,    0.88 -> goes to 2way Xover block
Filter 3: ON PK Fc 550.00,    1.40,    3.72 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 4: ON PK Fc 830.00,    -2.40,    1.83 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 5: ON PK Fc 1224.00,    -1.34,    9.45 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 6: ON PK Fc 1609.00,    2.11,    2.65 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 7: ON PK Fc 2764.00,    -2.80,    1.35 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 8: ON PK Fc 4747.00,    -3.40,    3.00 -> goes PEQ/6 Biquad block AFTER the Crossover

I then devised an EQ + Highpass filter that cuts at 80Hz@-3dB

HighPass EQ, Highpass filter enabled:

Preamp: -0.9 dB

Filter 1: ON HighPass Fc 75.31,    0.00,    1.48 -> goes to 2way Xover block
Filter 2: ON HighPass Fc 90.38,    0.00,    0.74 -> goes to 2way Xover block
Filter 3: ON PK Fc 152.65,    -3.17,    0.78 -> goes to 2way Xover block
Filter 4: ON PK Fc 550.00,    1.40,    3.72 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 5: ON PK Fc 830.00,    -2.40,    1.83 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 6: ON PK Fc 1224.00,    -1.34,    9.45 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 7: ON PK Fc 1609.00,    2.11,    2.65 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 8: ON PK Fc 2764.00,    -2.80,    1.35 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 9: ON PK Fc 4747.00,    -3.40,    3.00 -> goes PEQ/6 Biquad block AFTER the Crossover

Obviously the gains of each branch (Sub and LS50) should be tuned properly as well as the subwoofer correctly set up.

Here is the graphs showing the effect of the Xover (60Hz @-11dB compared to the Score EQ).

And the general graphs
With HighPass

Without HighPass

For those without a sub or a different configuration, the score EQ could be simply split over the two banks of PEQ/6 Biquad blocks before AND after the Crossover leaving 4 biquads for Room integration.

 

[ethernode]

@Maiky76 many thanks for your explanation, i did not think of splitting it into the 2 blocks, stupid me

To clarify, i use an SVS SB1000 sub (routed into output 2 below, summing both inputs) which i cross over at 86Hz with a 48 dB slope, and I am familiar with the auto EQ process with REW and the minidsp.

However i am still confused:
- how I am supposed to combine the REW auto-EQ and yours ?
- how am I supposed to recompute the lower filters when applying the high pass for the crossover (in REW?) Eg. If I wish to cross around 100 Hz or higher ?

For the record, on my 2x4 Advanced Plugin GUI there are 5 PEQ per block, not 6, see these screenshots (I believe minidsp released another Plugin), currently i manually enter your filter settings and split them as you suggested.

Sorry if this is common knowledge, and thanks again for sharing this.

 

[ethernode]

Hi,

I think it's 6BQ not 5 but whatever...
I don't know which the plugin you are using, anyways, you can split the EQ and distribute it over two blocks in both cases:
Links to the specsheets:

https://www.minidsp.com/images/documents/Product%20Brief-%202way%20Xover%2021%20ADV%20plug-in.pdf

https://www.minidsp.com/images/documents/Product%20Brief-%202way%20Xover%20ADV%20plug-in.pdf

2.1 case

View attachment 265919

2x4 case
View attachment 265920


Assuming you want to keep the 6 Biquads BEFORE the Crossover for Bass EQ/Room integration (which you should be doing too) and that you kept the passive Xover in the LS50 and therefore using a single channel from the MiniDSP to apply the EQ (in 2x2 configuration i.e. both Tweeters paths are unused for example in the 2x4 ), I have devised 2 ways to proceed. There may be others but I don't know your system structure...

Note that you may have to use the Advance setting in the Crossover block in order to program the correct coefficients to set the rest of the Xover block to "by-pass" you'll need to copy and past in the right block. REW can do the calculation (sampling rate is 48kHz) and the export in the correct format for you.
The PEQ/6 Biquad block should be filled by just entering the values I shared without the need for advance mode, but I might be wrong...
There plenty of tutorials on the web or even on Youtube...

Equaliser Selection

"The miniDSP equaliser setting supports the same filter types and resolutions as the Generic setting, but for 6 filters operating at 48 kHz. It is aimed at the miniDSP plug-in Advanced mode, which allows filters to be specified by their biquad coefficients. The Save Filter Coefficients to File action writes the filter coefficients to a file in a format suitable for use with the miniDSP software (note that the a1 and a2 coefficients are negated per the miniDSP format). An advantage of this is the very high filter frequency and Q resolution it allows, permitting exact targeting of modal resonances. The miniDSP plug-in has an Import REW File button on its Parametric EQ configuration screens to load the files."

And there

REW AutoEQ step by step

miniDSP is a leading manufacturer of Digital Audio Signal Processors for the HomeTheater, Hifi, headphone and Automotive market. Join our large community of Audiophiles, Engineers and DIYers using our innovative products.

www.minidsp.com

Score EQ, no Highpass filter enabled:

February202023-114538

Preamp: -2.6 dB

Filter 1: ON PK Fc 65.00,    3.00,    1.78 -> goes to 2way Xover block
Filter 2: ON PK Fc 166.50,    -2.10,    0.88 -> goes to 2way Xover block
Filter 3: ON PK Fc 550.00,    1.40,    3.72 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 4: ON PK Fc 830.00,    -2.40,    1.83 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 5: ON PK Fc 1224.00,    -1.34,    9.45 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 6: ON PK Fc 1609.00,    2.11,    2.65 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 7: ON PK Fc 2764.00,    -2.80,    1.35 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 8: ON PK Fc 4747.00,    -3.40,    3.00 -> goes PEQ/6 Biquad block AFTER the Crossover

I then devised an EQ + Highpass filter that cuts at 80Hz@-3dB

HighPass EQ, Highpass filter enabled:

Preamp: -0.9 dB

Filter 1: ON HighPass Fc 75.31,    0.00,    1.48 -> goes to 2way Xover block
Filter 2: ON HighPass Fc 90.38,    0.00,    0.74 -> goes to 2way Xover block
Filter 3: ON PK Fc 152.65,    -3.17,    0.78 -> goes to 2way Xover block
Filter 4: ON PK Fc 550.00,    1.40,    3.72 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 5: ON PK Fc 830.00,    -2.40,    1.83 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 6: ON PK Fc 1224.00,    -1.34,    9.45 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 7: ON PK Fc 1609.00,    2.11,    2.65 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 8: ON PK Fc 2764.00,    -2.80,    1.35 -> goes PEQ/6 Biquad block AFTER the Crossover
Filter 9: ON PK Fc 4747.00,    -3.40,    3.00 -> goes PEQ/6 Biquad block AFTER the Crossover

Obviously the gains of each branch (Sub and LS50) should be tuned properly as well as the subwoofer correctly set up.

Here is the graphs showing the effect of the Xover (60Hz @-11dB compared to the Score EQ).


View attachment 265916
And the general graphs
With HighPass

View attachment 265917
Without HighPass

View attachment 265918
View attachment 265914
View attachment 265915
For those without a sub or a different configuration, the score EQ could be simply split over the two banks of PEQ/6 Biquad blocks before AND after the Crossover leaving 4 biquads for Room integration.

For the record i posted a tutorial for my MiniDSP advanced plugin, i hope it helps someone.

MiniDSP 2x4 advanced plugin tutorial: integrating anechoic EQ filters

Hello everyone; i'm relatively new to this, and struggled a bit to setup, so i thought i would share what i learnt. To put things into context, i had the opportunity to buy Kef LS50 (1st gen) for a very low price (380€) and i own a used MiniDSP 2x4 (non-HD, the 48 Khz one, which i bought used...

www.audiosciencereview.com

@Maiky76 i would really love filters optimized for a 100 Hz crossover frequency, as this frequency has been suggested by many to be fitting the LS50s

 

[valerianf]

Going to Best Buy yesterday, I listened to a pair of LS50 connected to a Yamaha RX-A6.
The sound quality was meh: no low frequencies reproduced, and I could clearly detect the 4.6 khz peak.
This is not a good speaker choice for me.

 

[Doodski]

LR50 connected to a Yamaha RX-A6

What is a LR50?

 

[Kw6]

If you don't need wireless speakers and it's in your budget I highly recommend the Kef R3!

 

[valerianf]

"What is a LR50?"
Typo error: LS50

 

[Beave]

Going to Best Buy yesterday, I listened to a pair of LS50 connected to a Yamaha RX-A6.
The sound quality was meh: no low frequencies reproduced, and I could clearly detect the 4.6 khz peak.
This is not a good speaker choice for me.

This doesn't quite make sense.

Best Buy still has the original LS50 for sale? I doubt that.

Most likely you heard the LS50 Meta, which does not have the peak at 4.6kHz. So I'm not sure what you heard.

 

[Angsty]

Going to Best Buy yesterday, I listened to a pair of LS50 connected to a Yamaha RX-A6.
The sound quality was meh: no low frequencies reproduced, and I could clearly detect the 4.6 khz peak.
This is not a good speaker choice for me.

The Yammy may not be a good fit for the LS50. It requires a true 4 ohm capable amp and the RX-A6 is a multichannel AV amp. I get good low frequency response in my room with my Bryston.

 

[valerianf]

"So I'm not sure what you heard."
Me too I am not sure.
According to the shop listing it could be a LS50META or a wireless version (LSXII or LS50 wireless II).
I was surprised with the unexpected low sound quality and went away of the show room.
The room EQ of the Yamaha amplifier may have been wrongly adjusted.