Rythmik F12se vs KEF KC62

[Georgeadv]

So get an amp with a crossover or use external DSP to add it. It doesn't matter how good the amp is, without the ability to high-pass the speakers you are severely limiting the overall quality of your system.

This is a basic physics problem. The speaker cone has inertia, so when asked to play 2 frequencies at once, it cannot play both perfectly, and the further apart the 2 frequencies are, the worse it becomes. This is known as intermodulation distortion, and is more significant than simple harmonic distortion.

So by not high-passing your speakers, you compromise the entire mid-bass/mid-range spectrum.

I could do that but why the majority of hifi companies and audiophiles refrain from doing that?
minidsp is a good solution but a lot pricier and better performing dacs do not have such function

 

[alex-z]

I could do that but why the majority of hifi companies and audiophiles refrain from doing that?
minidsp is a good solution but a lot pricier and better performing dacs do not have such function

The majority of "audiophile" and "hifi" companies are more concerned with appearance than performance. A lot of consumers have been mislead into thinking they don't need proper subwoofer integration, which plays into the hands of these companies, because most of them don't produce good subwoofers.

This is why many people run an AV receiver instead of a stereo amp, because the included features far outweigh any performance gap. In some cases, the receivers are actually outperforming the stereo amps.

 

[Georgeadv]

The majority of "audiophile" and "hifi" companies are more concerned with appearance than performance. A lot of consumers have been mislead into thinking they don't need proper subwoofer integration, which plays into the hands of these companies, because most of them don't produce good subwoofers.

This is why many people run an AV receiver instead of a stereo amp, because the included features far outweigh any performance gap. In some cases, the receivers are actually outperforming the stereo amps.

Why they do not integrate those into the dacs like minidsp? It is a separate box anyway and a crossover would not drastically affect the shape or design of the dac

 

[alex-z]

Why they do not integrate those into the dacs like minidsp? It is a separate box anyway and a crossover would not drastically affect the shape or design of the dac

Because most consumers want a single function DAC. Something like the miniDSP 2x4HD is flexible enough that the learning curve intimidates users, even though it actually only takes a few minutes to get setup. A bit like the mentality of building a PC vs buying one. Better end product vs convenience.

Of course, there is nothing stopping you from going DAC -> subwoofer (internal crossover) -> amp -> speakers. The external DSP is better but not essential.

 

[Georgeadv]

Because most consumers want a single function DAC. Something like the miniDSP 2x4HD is flexible enough that the learning curve intimidates users, even though it actually only takes a few minutes to get setup. A bit like the mentality of building a PC vs buying one. Better end product vs convenience.

Of course, there is nothing stopping you from going DAC -> subwoofer (internal crossover) -> amp -> speakers. The external DSP is better but not essential.

So you reckon that a mini dsp would yield better results than a holo audio may dac?

 

[richard12511]

So you reckon that a mini dsp would yield better results than a holo audio may dac?

Definitely, and by quite a lot. Proper sub implementation makes a huge difference. IMHO, DAC performance doesn't really matter at all, as even the bad ones are still often perfect to beyond the limits of hearing. I think ASR has unfortunately led many people to believe that DAC performance matters greatly(look how popular the DAC measurement threads are). DAC's should be bought based on feature set(inputs, outputs, etc.) and what you need. The difference between your right and left LS50 is an order of magnitude more than the difference between DACs.

 

[witwald]

As my system currently stands and after eq up to 200hz to address some room modes (presumably) my LS50 roll off at 35 Hz.

Are you sure about that 35 Hz value? KEF's specifications for the LS50 state a frequency response of: 47 Hz to 45 kHz (–6dB), or 79 Hz to 28 kHz (±3dB). The low-frequency cut-off is much higher than what you have mentioned, and this will significantly affect the filtering needed in order to blend in with a subwoofer.

 

[Georgeadv]

Because most consumers want a single function DAC. Something like the miniDSP 2x4HD is flexible enough that the learning curve intimidates users, even though it actually only takes a few minutes to get setup. A bit like the mentality of building a PC vs buying one. Better end product vs convenience.

Of course, there is nothing stopping you from going DAC -> subwoofer (internal crossover) -> amp -> speakers. The external DSP is better but not essential.

So you reckon that a mini dsp would yield better results than a holo audio may dac?

Are you sure about that 35 Hz value? KEF's specifications for the LS50 state a frequency response of: 47 Hz to 45 kHz (–6dB), or 79 Hz to 28 kHz (±3dB). The low-frequency cut-off is much higher than what you have mentioned, and this will significantly affect the filtering needed in order to blend in with a subwoofer.

yes, please refer the measurements posted before

 

[Georgeadv]

Definitely, and by quite a lot. Proper sub implementation makes a huge difference. IMHO, DAC performance doesn't really matter at all, as even the bad ones are still often perfect to beyond the limits of hearing. I think ASR has unfortunately led many people to believe that DAC performance matters greatly(look how popular the DAC measurement threads are). DAC's should be bought based on feature set(inputs, outputs, etc.) and what you need. The difference between your right and left LS50 is an order of magnitude more than the difference between DACs.

That is very interesting and should be brought to the attention of the public!

what do you mean the difference between the L and R LS50? The difference in room?

 

[witwald]

What do you mean the difference between the L and R LS50? The difference in room?

I think that there are two things at play here: 1) the matching between the left and right speakers that came off the production line and which your purchased, and 2) the effect of the non-symmetrical room layout, with one of the speakers being closer to a corner and reflective surfaces than the other. The first is likely to be a relatively much smaller effect than the second.

 

[witwald]

Yes, please refer the measurements posted before.

Out of curiosity, what microphone are you using for your measurements?

I have had a close look at those measurements. I find it somewhat odd that a loudspeaker that has a specification of being –6dB at 47 Hz has such a strong response down at 35 Hz. It doesn't seem to make sense in light of the fact that the ASR measurements seem to support the published specifications within a few hertz. It would seem that your LS50s have extended their bass response by almost an octave, and now have the low-frequency response that one would expect from larger floor-standing loudspeakers.

 

[Georgeadv]

Out of curiosity, what microphone are you using for your measurements?

I have had a close look at those measurements. I find it somewhat odd that a loudspeaker that has a specification of being –6dB at 47 Hz has such a strong response down at 35 Hz. It doesn't seem to make sense in light of the fact that the ASR measurements seem to support the published specifications within a few hertz. It would seem that your LS50s have extended their bass response by almost an octave, and now have the low-frequency response that one would expect from larger floor-standing loudspeakers.

Yes i think i have timing issues with the left speaker…
I was using minidsp u1 mic for the measurements

 

[Tokyo_John]

It is interesting that people on this forum only discuss the KEF KC62...the slightly bigger (and similarly designed) KF92 is rarely mentioned. These are said to be designed for the LS50-series and R-series, respectively. Both of these KEF subs are optimized for music.

I recommend re-thinking this plan. Your LS50's will sound more clear if you relieve them of the stress of low-bass which they do not do well. They will also be easier to integrate smoothly, and you'll be getting a lot more bass by not limiting the sub so much.

It is true that the KEF LS50 (or any other bookshelf 2-way) can benefit greatly if it is liberated from bass duties and can focus on mids and highs (where the coaxial driver and its exceptional imaging really sets them apart).

This, I really doubt. I run Buchardt S400's, and they crush the LS50 in bass output. THEY go down to 35 Hz in-room. I believe the KEF R3 should be close to that as well. The LS50 does not do bass nearly as well as the R3. I would be surprised if you were getting anything below 60 Hz. Generally people need to cross the LS50 at 100 Hz.

It depends on the room and placement. Away from a back wall, the LS50 do struggle with bass under 60 Hz. But with a cement back wall and closer placement (with foam port inserts) the bass is good in the 80s dB-SPL range down to 40 Hz before serious roll-off...the E string on a bass guitar. I've measured with a calibrated miniDSP microphone and it works surprisingly well (could also depend a bit on the pairing amp). I didn't expect it, but there it is. Funny that this is what KEF recommends NOT doing in their instruction manual.

 

[yllanos]

There isn't even a contest here. Rythmik all the way my friend. Trust me, you will not regret it. I own a LV12F and I also live in an apartment, you can always tune that thing as you need. Those subs do require time and patience to setup and learn all the options they offer.

But yes, if your amp doesn't have a crossover feature, you may need a minidsp or some other device to work. The sub offers a low pass filter from 50-120Hz IIRC, but you may need to implement a high pass filter for your L/R speakers.

 

[KMO]

I have had a close look at those measurements. I find it somewhat odd that a loudspeaker that has a specification of being –6dB at 47 Hz has such a strong response down at 35 Hz. It doesn't seem to make sense in light of the fact that the ASR measurements seem to support the published specifications within a few hertz. It would seem that your LS50s have extended their bass response by almost an octave, and now have the low-frequency response that one would expect from larger floor-standing loudspeakers.

There is a reason for this - KEF have a signature low-end curve in most of their ported speakers. They tune the port low to have a gradual roll-off from 80-100Hz to the port frequency, with energy being redirected to low bass. They're targetting more even in-room response at low frequency, on the assumption they'll get room reinforcement.

Most manufacturers seem to tune their ports higher to immediately pick up and extend the anechoic linear region of their response as much as possible, but after that it drops sharply.

In their current Reference range, KEF actually supply two different port lengths you can use to choose between the two options, and these diagrams from the white paper illustrate the two responses (both relative to a sealed box in green). Long port (normal KEF response) is in blue, and short port (Reference alternative, similar to other speakers) is in purple.

The choice of tuning doesn't massively affect the -3dB or -6dB value, so doesn't really show up on the specs. (eg Reference 1 is -3dB at 45Hz with either port, and -6dB only shifts from 40Hz to 37Hz).

But it means you get unusually extended in-room response - as long as you've got a room with solid walls able to help. Conversely KEFs will struggle (relative to other speakers with the same -3dB values) in some rooms, and only the References provide the alternative port to help with that.

Jack Oclee-Brown discusses the Reference tuning here (and grumbles about the bungs used for tuning in their cheaper products).

 

[JWAmerica]

Get an AVR. The best Chinese chip amps still don't have adjustable sub out. Even if you don't need multichannel the xover and DSP options are very useful for a 2.1 setup.

 

[MalinYamato]

hi sub gurus.... is there a simple way to choose a sub given your main speakers and room configuration? A software that inputs your speakers and room config and outputs the recommended sub would be very useful? Any such software online?

 

[Willem]

Of these three things, power/extension, low price, small size, you can only have two. To get the most out of a small box, dual opposed subwoofer drivers seem to be the best technology, but it is nota cheap solution. If size does not matter too much, Kef also have the cheaper and larger Kube series. For some comparative measurements of the Kef KC62 and the SVS 3000 micro, see here:

The Kef has a flatter response, and goes remarkably low, but only at moderate levels. The Kef Kube series similarly have a flatter response than the SVS SB series. If esthetics also come into the story, I think the Rythmiks are mostly fugly, but de gustibus non est disputandum.

 

[Chromatischism]

The frequency response is going to be modified by room correction anyway.

 

[Vacceo]

This is a good thread to ask for something technical about subwoofers: spl output and extension seems to be dependent on both power of the amp and size of the cone (or cones). The second can be designed in many ways to archive extra performance such as less distortion, but how does the baseline work? How does power and cone size contribute to SPL and extension?

The bottom line of the question is understanding what is more important, raw power on the amp or size of the cone and how they interact in a bit more nuanced way. Yeah, I know, get a JL Audio Gotham and forget about the rest, but I´d like to know what is going on with a washing machine like that.