Neumann KH120 Disassembly Pictures

[hyperplanar]

Ah, forgot about that.

I don't know if I should be baffled or impressed that they are doing it without a micro in there.

The KH120 was released in 2011 and presumably in development for several years before that, so not too surprising that they opted for a non-DSP design. I would expect a successor to come out within the next few years with DSP which would allow for a smaller PCB without all the filter circuitry seen on the current one. That being said, the frequency response and directivity achieved in all analog are quite impressive nonetheless.

 

[hyperplanar]

A bit surprised to see a stamped woofer here

Seems like Neumann went out of their way to customize a woofer with good characteristics, and opted for a stamped basket for the cost savings. If that freed up some of the budget to be put towards more performance relevant aspects of the design I’m all for it.

Another thing to note is that the same tweeter is used in the KH310 and KH420. The whole is greater than the sum of parts and all that!

 

[AnalogSteph]

Another thing to note is that the same tweeter is used in the KH310 and KH420. The whole is greater than the sum of parts and all that!

Not 100% sure about KH310, but the THD graphs would certainly suggest so for KH80 and KH420. The part seems a bit overdressed for the little KH80. I guess the cost savings from buying the same tweeter in bulk and using it everywhere outweighed any that could have been gained by using another, smaller tweeter. It's a good performer either way, just like the woofer.

It is perhaps more baffling that a design this recent would still be chock full of TL074 and MC33079 opamps. Mind you, good quad opamps are not exactly growing on trees, and the electronics may have been based on the older O110 which had been around since 2002... not fixing what isn't broken and all that. Doing this all-analog would have been standard for the day, Genelec and others were no different.

I never noticed that the TDA7293 has such a large gap between A-weighted and 20-20k flat noise... might mean it's mainly got a bunch of 1/f noise but not that much wideband. This may put it ahead of the LM3886 despite the higher minimum stable gain requirement.

 

[thewas]

A bit surprised to see a stamped woofer here

Sensible engineering companies like Neumann, Genelec etc. concentrate just on what matters, that is measurements, not on "boutique" components like most Highend audio companies which cannot produce such a objective perfection and instead try to dazzle with such.

 

[hyperplanar]

Not 100% sure about KH310, but the THD graphs would certainly suggest so for KH80 and KH420. The part seems a bit overdressed for the little KH80. I guess the cost savings from buying the same tweeter in bulk and using it everywhere outweighed any that could have been gained by using another, smaller tweeter. It's a good performer either way, just like the woofer.

Hmm, I remembered seeing a confirmation somewhere online about the same tweeter being used across the whole line, but there's this snippet from Sound & Recording's review of the KH120 at least:

Maybe the differing waveguide sizes play a factor in the THD graphs due to the difference in the resulting acoustic loading?

I never noticed that the TDA7293 has such a large gap between A-weighted and 20-20k flat noise... might mean it's mainly got a bunch of 1/f noise but not that much wideband. This may put it ahead of the LM3886 despite the higher minimum stable gain requirement.

This is a pointless comparison but... I'm a 25 year old with healthy hearing and I literally can't hear any hiss unless my ear is inside the waveguide. I had a previous studio monitor with LM3886 amplification and the hiss was easily audible, but it's unlikely the implementation of that amp was nearly as careful as the KH120's.

 

[Kachda]

I am planning to get there as desktop speakers in the near future. Has anybody tried them in that manner and their impressions ?

 

[Vintage57]

I am planning to get there as desktop speakers in the near future. Has anybody tried them in that manner and their impressions ?

I have a pair and they are amazing for the punch and imaging they have. I also have kH420’s next to them and I prefer the KH120’s with soloist or small ensembles.

I unfortunately don’t have them on my desktop. I think they would be overkill at less than a meter. YMMV

 

[AnalogSteph]

FWIW, I'm using the preceding model O110 as my PC speakers at <0.5 m on some ca. 23 cm (9") high desktop stands that Dad and I built 13 years ago. I would really recommend something like that as it keeps early reflections and frequency response warping at bay to some degree. At the time you couldn't really buy anything like that so a trip to the home improvement store and some woodworking it was.

The setup generally works fine, the main acoustic issues I'm having seem to relate to the back wall and the nearby room corner to the left (not sure how much of a disturbance the monitor is). For now I've hung a thick blanket behind the speakers, but that's not really a long-term solution. Making or buying some sort of absorption panels would probably be a good idea.

 

[thewas]

I am planning to get there as desktop speakers in the near future. Has anybody tried them in that manner and their impressions ?

Mine arrived today as a replacement for my desktop KEF LS50 and JBL LSR 305, like all linear loudspeakers they usually need quite some EQing below 1 kHz when located close to nearby surfaces like walls and desk, but this can be partially be done with the filters they have on their back or even better with some external measurements and EQ (I use Audiovero Acourate).

 

[ernestcarl]

I think they would be overkill at less than a meter. YMMV

Well, I do have mine less than a meter... but I got them years ago before the KH80's came out -- and I didn't pair it with a sub then.

If I bought monitors today, a pair of KH80s and a sub for very nearfield use should be fine -- although I would still prefer to upmix most of everything to mch surround (if possible) -- as I do like the sensation of 'liveness' it adds.

 

[racingpht]

Hello. I am the original poster in the Chinese forum and I'm happy that you enjoy my post.
As is obvious, I'm very impressed with the engineering of KH120 and its attention to detail is even better than the Genelec 8040b I also disassembled(not posted)

A bit surprised to see a stamped woofer here

Don't worry about the woofer. it's clearly very customized and you don't usually find similar performance in high-end audio for 2 reasons:
1: very low inductance. Clearly there's copper cap in the motor, results in motor distortion at similar level of peerless' own high-end NE149, without the fancy aluminum basket.
2: very high rubber surround edge resonance frequency, at about 2khz. Normally woofer of similar size will have edge resonance at 1.3~1.5khz resulting a 2nd distortion peak. by pushing this resonance higher up to crossover frequency, the distortion peak is absent from kh120's system distortion graph.

 

[Pearljam5000]

They need to do a 6.5 inch and 8 inch version of the KH120

 

[Pearljam5000]

Hello. I am the original poster in the Chinese forum and I'm happy that you enjoy my post.
As is obvious, I'm very impressed with the engineering of KH120 and its attention to detail is even better than the Genelec 8040b I also disassembled(not posted)



Don't worry about the woofer. it's clearly very customized and you don't usually find similar performance in high-end audio for 2 reasons:
1: very low inductance. Clearly there's copper cap in the motor, results in motor distortion at similar level of peerless' own high-end NE149, without the fancy aluminum basket.
2: very high rubber surround edge resonance frequency, at about 2khz. Normally woofer of similar size will have edge resonance at 1.3~1.5khz resulting a 2nd distortion peak. by pushing this resonance higher up to crossover frequency, the distortion peak is absent from kh120's system distortion graph.

Can you compare KH120 to Genelec 8040 SQ wise ? Thanks.

 

[Pritaudio]

What does the sinad graph look like for the amp module. How does it compare to a purifi

 

[Ilkless]

w

Can you compare KH120 to Genelec 8040 SQ wise ? Thanks.

I thought the 8040 was the odd one out in the line-up. The 8030 is still excellent, as is the 8050 (well-executed 8-inch 2-ways are rare). The 8040 doesn't quite measure as well as either, and it shows out in subtle but perceptible ways. There's a slight rise towards 1kHz, that I hear as a bit of a "plasticky" timbre vs speakers linear in that range in the same position (Hedd Type 07, but that had even worse midwoofer-tweeter integration and tweeter was disappointing vs the ADAM implementation). What it will have is headroom though, for the form factor.

 

[Zvu]

What does the sinad graph look like for the amp module. How does it compare to a purifi

Given the datasheet for the chip itself, Purifi will wipe the floor with TDA7293 measurably in any known or unknown application.

 

[AnalogSteph]

That said, in an active speaker you only need distortion better than the driver's, which usually is not a particularly high bar to clear.

 

[Zvu]

^For some small nearfield loudspeakers you're right. If you have larger speakers that you listen from distance of 3-4 meters you do need an amplifier that keeps thd/imd low at higher volumes. Especially if those are low sensitivity drivers to begin with (as are woofers in Kii3 and Purifi 6.5" woofer).

 

[racingpht]

Can you compare KH120 to Genelec 8040 SQ wise ? Thanks.

Personally I don't like the sound of 8040. In my room the sound stage seems to have issues, sounds like tweeter/woofer integration. It's a mystery to me. KH120 to me sounds better than many similar sized small speakers such as LS50.

^For some small nearfield loudspeakers you're right. If you have larger speakers that you listen from distance of 3-4 meters you do need an amplifier that keeps thd/imd low at higher volumes. Especially if those are low sensitivity drivers to begin with (as are woofers in Kii3 and Purifi 6.5" woofer).

I'm using Purifi PTT6.5 right now and indeed it's probably one of the best woofer on the planet, I'm sure it's a huge step ahead of KH120's woofer presumably in the LSI/klippel BL curve wise.

OTOH Kii's woofer/midrange is probably the Peerless SBS/FSL range, which are probably low-end drivers. But Kii's system design is unique and is another level, which maximized or even enhanced the midrange performance to high-end standard, but woofer distortion is still not very great. I think ncore is a bit overkill in the woofer range.

That said KH120's woofer still has all the necessary high-end features such as low inductance, in-band piston cone, and decent excursion thanks to excellent ventilation under its spider, it just "look" like a budget driver. KH120's system design is also taking extra advantages of it. For a 6inch or 8inch version 2-way, I think it's not possible to push the edge resonance frequency high enough to be covered by crossover, as seem on Dynaudio's Core7 measurement.
https://estradaistudio.pl/testy/sprzet-studyjny/1527-core-7-monitory-aktywne/1527/9387

 

[Pritaudio]

Problem with passive is the crossover. not sure the purifi crossover can be used with other tweeter for integration. Is it a case of trial and error, or can it be narrowed down with a given enclosure.
If only there was a mass market purifi active speaker maker. It would clean up the market.