Apollon Hypex NC2K Monoblock Amplifier Review

[Vasr]

Some may find this study of the range of the spectrum of different musical instruments useful

https://www.cco.caltech.edu/~boyk/spectra/spectra.htm

 

[Blumlein 88]

I would also like to add that it is an unfair assumption that perceiving those frequencies would enhance one's musical listening experience. I would imagine it to be quite distracting from the artists intention if I had that level of hearing ability.

So go take one of those hearing tests at an audiologist. Don't respond to anything above 2khz, and let us know what they think of the condition of your hearing.

 

[Dmitri]

So go take one of those hearing tests at an audiologist. Don't respond to anything above 2khz, and let us know what they think of the condition of your hearing.

Which is why I fear the audiologist as much as I’d fear an emotionally scarred Yeti with anger management issues.

 

[Chromatischism]

Alvin Silvestri's Ready Player One soundtrack has a lot of what sounds like a triangle or other really high frequency instrument. I've seen it put out sound up to 15 kHz at a decent SPL, with some small bits registering at 17 kHz. Then there are harmonics. This is an album that people will certainly hear differently depending on age. And just maybe, could show a difference between an amp with -0.5 dB at 20 kHz vs one that extends higher. But it's a rare case.

 

[NTK]

As shown in the figure, the low distortion power of 4Ω is only 800W instead of the nominal 2000W. . . . . I found that companies like HYPEX Class D amplifiers like to mark the power very exaggeratedly, and this marked power is a distortion power that is completely unreferenced. . Ha ha da

Curious to know what level of distortion you expect from your speakers when they are driven with a 2000 W signal.

 

[YogiN]

Uh, what?

What makes a musical instrument different from a sine wave generator and from each other are the overtone (natural harmonics) spread over the spectrum. A single note from a violin is rich in harmonics at progressively lower volume away from the note frequency and what makes you recognize it as a violin. In addition, musicians often make the instrument produce artificial harmonics with the way they play that could be quite high in frequency.

Depending on one's hearing ability (and musical experience), different people hear up to different limits. 20khz is roughly taken as the limit of human hearing.

So anything produced from a musical instrument is "musical content" by definition. I am not sure what you think musical content is. The notations on a music sheet?

Oh no! Disparaging emoji alert!

The post from Blumlein I responded to cited "4186hz for the 88th key. And there will be overtones. Cymbals often are around 8-12 khz" which is well withing the limits of these monoblocks. Assuming that there are no musical recordings registering above Chromatischism's outlier example of Ready Player One soundtrack at an upper range of 17khz then the limitation on audibility is not the average of human hearing or in the case of this thread the Apollon NC2K but the limits of sound frequencies that the musical instruments can produce.

Can you cite a violin recording that registers frequencies beyond the limits of these amps? A quick google search cites 659.3 Hz but I really don't know personally and so I can't confirm its veracity.

Some may find this study of the range of the spectrum of different musical instruments useful
https://www.cco.caltech.edu/~boyk/spectra/spectra.htm

Very interesting! Thank you for sharing. The information certainly contradicts the results of my Google search. Since I really don't know much about what might be the confounding factors for disparities in musical measurements I'll hold off on commenting. But I will ask, are there any musical recordings that you know of that output higher than 17kHz?

So go take one of those hearing tests at an audiologist. Don't respond to anything above 2khz, and let us know what they think of the condition of your hearing.

No thank you

 

[Frank Dernie]

In real terms it's been that way for 50 years or more with HiFi, especially the Japanese. Not many of the "big" names of the past made all of their own product and in many cases, some hardly made much at all. They outsourced the entire products, right down to the cardboard boxes to OEMs.

I don't have a problem with every man and his dog screwing Hypex modules into boxes and selling them on at (hopefully) a profit. But let's call them assemblers, not manufacturers in the true sense of the word.

When I was at Garrard they were losing out because they didn't have other items to offer.
One of the OEM units we got to evaluate was a cassette deck sold in the UK as a Pioneer but the OEM assured us Pioneer made none of it!
What was disappointing was that the nice feel of the controls was only achieved by them turning a disc covered in silicone gloop spring loaded against the chassis. They were actually turning "preset" type pots on the pcb
This was in the mid 1970s, the Pioneer retailed at a touch over £100 and the OEM would supply Garrard the units labeled and packaged for £10.

 

[Frank Dernie]

You simply can not rely on an average based on the speakers tested. It's not a good idea.
By doing this you simply put every speaker in the same bucket .There is no averaging on sensitivity.
No .
And apart from this , you can not judge all the speakers buy those tested by ASR.
This is way wrong.

My experience agrees with @andreasmaaan. HiFi speakers are around 86dB/watt.
There are more efficient speakers out there but they are big multi way speakers and IME the less expensive ones tend to be a bit peaky screechy and not all that "high-fidelity"

 

[Vasr]

Can you cite a violin recording that registers frequencies beyond the limits of these amps? A quick google search cites 659.3 Hz but I really don't know personally and so I can't confirm its veracity.

Very interesting! Thank you for sharing. The information certainly contradicts the results of my Google search. Since I really don't know much about what might be the confounding factors for disparities in musical measurements I'll hold off on commenting. But I will ask, are there any musical recordings that you know of that output higher than 17kHz?

People aren't here to put an effort into answering ill-informed questions. Instead of asking these arbitrary questions based on lack of information, given the new information above on the frequencies produced by musical instruments why don't you think/research why any recording would arbitrarily limit itself to 17khz and if you think there is a reason for it, make the case.

When you make nonsensical ill-informed statements like "anything above some arbitrary frequency is not part of musical content and not what the musician intended" which isn't supported by logic let alone knowledge, the onus is on you to support your thesis than simply say because so far I haven't seen anything on Google, prove me otherwise.

Otherwise, you are just wasting people's time.

 

[Frank Dernie]

Have you ever auditioned a cerwin vega ? their sensitivity is quite more than 92 db"s.
Not to mention some older infinity speakers.
What has gotten you with the average? Why do we have to average anything? Specially speaker's sensitivity's?

Yea but they aren't high fidelity they are brilliant excess excitement generators like a lot of early JBLs

 

[Frank Dernie]

Can you cite a violin recording that registers frequencies beyond the limits of these amps? A quick google search cites 659.3 Hz but I really don't know personally and so I can't confirm its veracity.

That is the fundamental. The overtones are multiples of this and it is their intensity and how many of them which defines the timbre of the instrument (how you can tell it is a violin not a whistle).
The characteristic timbre of an oboe is due to it producing 5th harmonic overtones iirc, if you don't reproduce the overtones the sound of the instruments, and the instrumental technique of the musician, will be wrong.
There is information produced by some musical instruments to a frequency higher than humans can hear, so ALL the frequencies you can hear will contain musical information, and without the higher frequency instrumental timbre is not accurately reproduced.

 

[restorer-john]

For you guys with Hypex modules and PEQ, why not program in the opposite of the FR plot (HF only) posted above to bring the amplifier up to flat at 20KHz and see if you can hear a difference on content when switched in and out?

 

[Matias]

99% here would not even hear 20 kHz full scale, even less the difference in 0.5dB!
Also music content usually is some -40 dB on 20 kHz, so 0.5dB there is even less significant!

 

[restorer-john]

99% here would not even hear 20 kHz full scale, even less the difference in 0.5dB!

Consider it isn't just -0.5dB@20KHz, it starts rolling off slowly at 5KHz to be 0.5dB down at 20KHz. Don't just look at a single point, look at the trend.

Subtle tilts in the overall frequency response of amplifiers can make them sound different- among another things.

 

[andreasmaaan]

For you guys with Hypex modules and PEQ, why not program in the opposite of the FR plot (HF only) posted above to bring the amplifier up to flat at 20KHz and see if you can hear a difference on content when switched in and out?

Or alternatively, regardless what amp you own, dial in a -0.5dB HF roll-off equivalent in frequency and Q to the roll-off of the Hypex modules and see if you can hear that.

 

[Soniclife]

Or alternatively, regardless what amp you own, dial in a -0.5dB HF roll-off equivalent in frequency and Q to the roll-off of the Hypex modules and see if you can hear that.

Or better yet measure your high frequency response and see the 0.5db is probably the least of your problems. FWIW I use a very low Q filter to raise the top end 1db, as my speakers are a little shy up there, I like the result.

 

[Blumlein 88]

Oh no! Disparaging emoji alert!

The post from Blumlein I responded to cited "4186hz for the 88th key. And there will be overtones. Cymbals often are around 8-12 khz" which is well withing the limits of these monoblocks. Assuming that there are no musical recordings registering above Chromatischism's outlier example of Ready Player One soundtrack at an upper range of 17khz then the limitation on audibility is not the average of human hearing or in the case of this thread the Apollon NC2K but the limits of sound frequencies that the musical instruments can produce.

Can you cite a violin recording that registers frequencies beyond the limits of these amps? A quick google search cites 659.3 Hz but I really don't know personally and so I can't confirm its veracity.





Very interesting! Thank you for sharing. The information certainly contradicts the results of my Google search. Since I really don't know much about what might be the confounding factors for disparities in musical measurements I'll hold off on commenting. But I will ask, are there any musical recordings that you know of that output higher than 17kHz?



No thank you

Recording I made of a violin. Audio Technica AT4033a microphone. Strong content to 4 khz with lower level content above that. No processing has been done to the track.
Okay so we now have evidence your 659.3 hz is ridiculous. Even for a fundamental it is wrong information on a violin.

I don't know what it is you have in mind. If one has wider bandwidth microphones there is content above 20 khz. However, above that it doesn't matter to us humans. And I'll agree most higher content is low in level most of the time with music. It is a bunch of bs about nothing. Sometimes some musical instruments produce short bits of high level high frequency content, and most of us can hear some of it. Amps that produce a flat response to 20 khz are not hard to come by so it is a non-issue.

I'm not sure what your point about all this is. You don't seem to understand the difference in a fundamental tone of a note and that it has harmonics.

 

[Chromatischism]

For you guys with Hypex modules and PEQ, why not program in the opposite of the FR plot (HF only) posted above to bring the amplifier up to flat at 20KHz and see if you can hear a difference on content when switched in and out?

We could – and this leads to another thing – that an EQ target applied to different amps would likely nullify any differences in sound, at the expense of headroom.

 

[Vasr]

For you guys with Hypex modules and PEQ, why not program in the opposite of the FR plot (HF only) posted above to bring the amplifier up to flat at 20KHz and see if you can hear a difference on content when switched in and out?

Not a direct answer but I have some related anecdotal experience.

In a new inexpensive pre/amp combo (which was fine for HT), I was getting annoying tizziness at the high end for music. So decided to do some experiments with PEQ varying cut-off frequencies and attenuation using a shelf filter (which has less artifacts than a narrow filter). When I did the raw measurement, I realized that there was a pronounced hump starting around 12khz and going up to about 18khz before dipping down.

I could take out that tizziness with some attenuation after 12khz (most of it to take out the hump to be flatter) but to arrive at that number, I tried a number of values to find the optimal (i.e., minimal attenuation needed). Using Equalizer APO, it is trivial to adjust in 0.1db increments and do quick A/B testing (not blind). I could not hear much of a change in the resulting sound (in this case, losing tizziness) for less than about 0.8db difference one way or the other.

But like detecting pitch difference, it also depended on the delta magnitude. So, if I went up in steps of 0.1, it was very hard to detect a difference with the preceding but if I jumped back and forth at least 0.8db in one step, I could hear a difference.

In terms of what this means in practice, my conclusions would be that this varies a lot from person to person (both the minimum delta and the frequency sensitivity). If you have been listening to music with less than 1db attenuation at those levels (rather than switching back and forth), you will likely not miss anything. However, that 1db difference may make the difference between something sounding too bright or tizzy or or too dull or just right depending on your sensitivity and that may become apparent only in A/B testing!

Note that because of the interaction with speakers and the room, a flat amp response may not necessarily sound "right", so it is quite possible that an amp which has a roll-off actually sounds good to you coming out of your speakers than one that is flat and vice versa.

So to be flat or not to be flat becomes a rather academic issue and difficult to predict based on measurements alone.

Someone should come up with the math and a tool for combining speaker and amp measurements and showing an effective curve with that combo. That might help choose the right combination if you have one of them and looking for the other.

 

[Chromatischism]

It could, but it's a lot easier to just choose all neutral electronics and then go shopping for loudspeakers.