Part 2. Sound check…
Two weeks passed since we’ve unboxed and reviewed Hidizs AP200 player and it is time to share our opinion about the sound quality together with the results of a couple of technical tests that were conducted couple of days ago.
In order to provide the most interesting test — we have visited the largest Ukrainian professional music store — JAM.UA (exclusive distributor of Yamaha, ESP, PRS, Kort and many other brands in our country).
We’ve met with Igor Kravcov there — he is one of the leading engineers in service section, mostly dealing with servicing and testing audio equipment. He agreed to help us with our quest and evaluate how good Hidizs AP100 & AP200 players reproduce sound throughout all AFR (amplitude-frequency response) range using M-Audio Audiophile Sound Card & SpectraLAB software.
What we were up to is to get AFR from both players using sinusoidal and pink noise signals and compare them against each other. The best result in such test would be to acquire straight line through the whole frequency response range while playing pure sinus signal and see the similar behavior of two players when «human natural» sinus is played.
Note: our ears would naturally accept more lows and mids than highs even if they are played with the same amount of volume. «Pure sinus» signal is formed to compensate this decay of high frequencies to represent the straight line on the graph. «Human natural» or «perceived» sinus is formed to reflect the natural hearing abilities of a human ear (volume decay at higher frequencies).
Why pure sinus straight line or perceived sinus similar bahavior line with a decay at high frequencies of both players are so important to us: this lines would tell us whether AP100 and AP200 are capable of producing all frequency response range evenly which results in precise, balanced and «analytical» sound with no additional tuning from the factory. Such audio source would have minimum to none influence on the recorded audio. EQ was turned OFF in both players, of course.
First, let’s check the previous AFR tests of AP100 conducted by the Reference Audio Analyzer Lab:
Edge decay at 20kHZ can be omitted due to high frequency interference error.
As seen from the picture — pure sinus signal with AP100 AFR results in a straight line through all frequency response range.
Our test of AP100 to check if we get the same result:
AFR decay of <30Hz can be omitted due to measure start lag.
So, as obvious — red line represents pure sinus which is a straight line through all frequency response range, light blue line represents natural or perceived sinus and yellow represents natural or perceived noise…
Now we know that our tests and RAAL tests of AP100 AFR have the same results — straight line throughout all frequency range. As many users already know or heard — Hidizs AP100 is usually called «a player with balanced and analytical sound with no peaks or roll offs at any frequency». Our tests reflect such meaning.
Now, let’s see the results for Hidizs AP200:
AFR decay of <30Hz can be omitted due to measure start lag.
Again, red line represents pure sinus which is a straight line through all frequency response range, violet line represents natural or perceived sinus and orange represents natural or perceived noise…
From this graph we can tell that AP200 is capable of reproducing all frequencies evenly. Thus, it has the same balanced and analytical sound characteristics of AP100.
AP100 & AP200 results (natural or perceived sinus and noise only):
AFR decay of <30Hz can be omitted due to measure start lag. We have set slightly different volume output on players to separate the lines one our graph.
Violet line represents natural sinus of AP200, light blue — AP100. Yellow line is natural noise for AP200 and red — for AP100.
Seems that sinus is equal for both players. Which means that they have similar balanced and natural sound throughout all frequency range… No coloring, all response range is even. Great source for any type of final audio reproduction gear — headphones, speakers, etc. The rest of the sound coloring can be done using EQ to your own liking.
Personal opinion about the sound quality:
I’ve spent about 10 hours now listening to Hidizs AP100 & AP200 players with my Yamaha RH-5Ma and Audio-Technica M20x headphones trying to find the difference in sound reproduction. Personally, I’ve found that AP200 is more capable of defining a bit wider stage with a bit more resolution on human voices and midbass and a bit less bright top octave. Midbass overtones are more obvious and top octave is a bit less sparkling but totally enough and well controlled to avoid unpleasant «hisses» that I’ve rarely heard with my AP100 when used with very bright and sparkling Yamaha RH-5Ma. On the other hand, using Audio-Technica M20x would force me to use EQ in both players and increase upper-highs to top octave a bit and slightly decrease low bass. M20x are closed type studio headphones pretuned for excellent resolution and reproduction of low frequencies which results in such EQ tuning. But their stage reproduction is wider, even despite their closed type. Some audio material player through AP200 with Audio-Technica 20Mx would obviously show longer distance of vertical and horizontal instrument separation. Let’s say, this is the first player which showed me how wide the stage on the recording could be and how far each instrument can be placed on any axis. Very good and new sound experience.
Note: such vertical and horizontal stage width can be heard clearly with hi-res audio formats and music genres that do not require much of equalization squeeze to sound «tough and thick». Such modern type of recording would loose a part of dynamic range and stage width in favor of popular sound. The best experience gained while listening to hi-res jazz, blues, classics, soul and slow old rock songs. If you’ve never heard what vertical instrument separation is — you have probably missed the right music 🙂
Despite some minor flaws in firmware (which should be eliminated with the upcoming FW version according to Hidizs latest replies) I fell in love with Hidizs AP200. I am not really considering all other possibilities like using Android OS for youtube or radio on this player (BTW — Hidizs replied that ESS DACs are always ON, no matter the running mode or application) — sound quality in pure mode is what interests me the most. And it seems that AP200 is very capable in this aspect, very balanced and perfectly tuned, slightly outperforming its predecessor AP100 in terms of stage width reproduction and resolution in some frequency ranges. Definitely a step ahead which brings audio listening experience to a higher level.
One reminder here: if you are interested in getting the least possible price for Hidizs AP200 now (when KickStarter campaign is over) — you can become a backer of Hidizs campaign on Indiegogo.