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理性派HiFi X5 Speaker Anechoic Chamber Measurements

Arthurdent

Member
Joined
Jul 24, 2019
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16
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Location
China
This content is the result of translation, please forgive me if you do not understand,要看中文去下载附件的txt.

Hello, I am Moondrop acoustic engineer, this is my first post in the ASR, to share with you what I saw today, today a friend commissioned me to help measure the GFSG119 X5 speaker, along with the door to listen to headphones and speakers, I have recently also been very interested in the results of this speaker measurements, agreed to help to measure the review.

As you know, Moondrop is a manufacturer and seller of headphone products, and has not yet started the loudspeakers business, so I am not good at measuring speakers, and the measurement conditions are inadequate, so please forgive me.

The internal size of our anechoic chamber is about 3.5 meters square, the reason why the room is so small, because our company is located in an office building, space is limited, and we need a quiet test conditions to do headphones, so in the limited space to build a free field anechoic chamber in order to Improve the measurement of headphones and noise reduction tests,This is not an anechoic chamber specification designed to measure loudspeakers.
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The actual noise level is about 32.8 dBA, can be seen in the B&K 4128C wearing such as HD580J, NAN6 typical open headphones after measurement, steady-state Noise Floor basically no change to meet the distortion measurement and noise reduction measurement capabilities of the headphones, is in line with our work requirements.
Noise.png
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Due to the time constraints of the senders and I did not have time to replace the calibration of the free field microphone, I could only use the GRAS 40AF 1/2-inch free field microphone that had been matched for measurement, in fact, I had the B&K 4938 1/4-inch pressure field microphone on hand, and had done 0° free field calibration, if used, in this test can better reduce the microphone due to Size of the high-frequency measurement errors caused by the size, but the current test conditions are limited, no matter how the measurement results will not be too accurate, can only selectively look at the results within a certain bandwidth, so there is no measurement microphone replacement to reduce the complexity of the work and reduce the workload.
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On the other hand, because the test-specific microphone stand borrowed to the factory, there is no standard microphone fixture, so only ordinary microphone stand, may produce some distortion of the measurement results above 10kHz, and the limited size of the anechoic chamber, the low frequency cut-off frequency is relatively high, the early reflections from the floor and wall sound is more obvious, will produce a certain comb filter, so only selective The measurement time window of the sound chamber is set at 10ms, and the measurement results can only be seen in the range of 200Hz-10kHz, apologies for any inaccuracies that may have resulted in the measurement results.

The measurement equipment is RME UCX sound card, has been working for many years, is an old comrade of Moondrop, and the measurement microphone is GRAS 40AF With B&K Nexus 2690, as well as the test using the amplifier is Topping LA90, A30pro is usually used to test headphones, shutdown will be passthrough to the LA90 amplifier, can meet the low Sensitivity headphone and speaker measurements, basically the conditions of the test, the next is the X5 86dB and 96dB frequency response measurement pictures, based on 50cm distance 0 ° alignment tweeter near-field time window measurement.
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I was surprised to find that the results I measured, and Amirm with Klippel NFS measurements derived from the characteristics of the high and medium frequency fluctuations are very similar, the measurement results put together will find that the fit is not low, there are some differences in sound pressure above 1kHz, but the characteristics of the point basically match, whether sample A or sample B, and the speaker has always been the owner at home for their own use, no bump, no express sea transport, so the possibility of damage is ruled out.
X5 Sample A.png
X5 Sample B.png

X5 AB.png

Harmonic distortion performance belongs to the normal level of bookshelf speakers of this size, without reproducing the abnormal resonance measured by Amirm, while the measurement results of sample B will be a little better.
Sample A 86dB
Sample A 96dB

X5 B 86 THD.png
X5 B 96 THD.png


I have also seen the anechoic chamber measurement pictures posted by GFSG119 before, the note is 50cm ± 15 °, I am a little puzzled, so I thought, why not use the noise measurement method to compare, so I will microphone to the speaker's center axis, the cumulative noise measurement, and then compressed the coordinates of the picture, I found and he posted a lot of similar pictures, but there are still some results on of matching dispersion, of course this my test conditions are to take the blame.
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X5 Noise mid.png

This also aroused my interest in measuring other speakers for comparison, so then I will we carry out PNC and ANC test of nine KH80 speakers for the same test conditions method of rapid measurement, set the conditions is to turn off the speaker adjustment function, set at 94dB gear 0dB input attenuation, measurement position placement to try to ensure consistency, the same found 200Hz-10kHz measurement, the and Amirm NFS-based measurements are basically a good fit, and surprised to find that the KH80 speaker pairing is very good! Not bad for a factory-calibrated speaker with satisfactory consistency. Harmonic distortion at low frequencies is more general, so it is recommended that KH80 speaker users, it is best to use electronic crossover or subwoofer management to increase the subwoofer use, crossover selection in 80-120Hz are available, while the harmonic distortion in the high frequency is the normal level of bookshelf speakers of this size, not good or bad, KH80's main problem is the limited power.
KH80 86-96.png
KH80 AB.png


KH80 THD 86.png
KH80 THD 96.png

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This has aroused the interest of the senders, so I and the senders of the X5 and KH80 speakers into the listening room after a simple placement, as well as the comparison of Salon2 speakers for listening, due to Mark Levinson amplifier access to the Revel Salon2, not convenient for plugging and replacing, so the senders of their own SMSL DA9 amplifier was used.
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Audition process found that the X5 speaker low and high frequencies are clearly inadequate, lacking texture and dynamics, feel unlike the size of the bookshelf speakers should have low frequency output performance, but the performance of the vocal midrange is still considered silky smooth, and the sound field background integration is more natural, and will not feel any abruptness, but also lack of emotion and musicality, The good thing is that the speaker is not found in the case of high-powered output what is very unusual distortion hearing.
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Then we switched to KH80, my goodness, I never found KH80 speaker, in contrast, has such a ferocious output capacity, the sound field filled the room, as if not inferior to the Salon2 speaker behind, I used to use it in the anechoic chamber, often complained that his noise output power is not particularly adequate, it is easy to alarm flashing red LEDs, but in this contrasting conditions with better performance. Its high-frequency smooth not harsh, mid-range vocals also have a little three-dimensional sense, but compared to Salon2 in the sound texture and detail of the filling touches are quite poor, the low-frequency output capacity as if not a 4-inch speaker should have performance, slightly muddy sense, after listening for a while, the send testers and I talked for a while, stopped the speaker review, a long time can not calm.

I do not know how to evaluate this speaker made by GFSG119, after all, I do not know what he really thinks, which requires your own judgment. Admittedly he seems to understand what kind of speaker is a good speaker, after all, he has advertised his former work, contacts and in the play of things, but also carried out a lot of scientific popularization work, deserve to make at least will make the listener feel good speaker, many people therefore trust him, based on the previous review, in the face of the X5 speaker this product, with the results I heard and saw today is truly disappointing, therefore So my recommendation rating is not recommended.

Admittedly, the X5 speaker only $ 289, is not a very expensive product, compared to the KH80 speaker I compared today. But today's increasingly competitive market, more and more emerging brands, new ideas, new technologies, new designs are introduced in large numbers, more and more features, performance is getting better and better, with cost-effective products are emerging, I believe that is why many people love to see the results of Amirm and Erin measurement of speakers, many people want to be more convenient and lower cost from the market to find a good product. Likewise, I still hope that businesses in the posting of measurement results, can be more standardized and serious, whether you are using NFS or anechoic chamber measurement speakers, if you can honestly post a somewhat poor frequency response test chart, but also far more responsible than you on a Fake Eye-Fi test picture to.

(X5、KH80、MTM Anechoic Chamber Mono Recording ,Random selection of music without commercial rights)

(REW File)

MTM AB.png
MTM 86-96.png

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MTM 96 THD.png
 

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Looks like the THD spike (probably from the broken screwhole?) is an isolated incident, frequency response is still the same business though, for better or for worse. The NFS results basically check out with anechoic results (again), always a good thing to see.
 
Welcome and thank you for posting your measurements and observations! It's great to have more people creating more measurements!

Also, I appreciate your screen name. :) Just remember, the answer to life, the universe, and everything is 42!
 
Thanks for your work!These data reflect many problems. I think everyone get the truth.
 
@amirm will surely appreciate more people participating with measurements and comparing. Always good to have someone to compare measurements with.
 
This is very interesting, thank you. I smiled when I read about your reaction on comparing a speaker in a room rather than an anechoic chamber. Speakers do sound much quieter when there is no room gain!
 
What a great work with all the details described clearly and we can learn from it a lot if we want to perform measurement of our own speakers.

The frequency response consistency between different KH80 individuals is just AMAZING!
 
This is very interesting, thank you. I smiled when I read about your reaction on comparing a speaker in a room rather than an anechoic chamber. Speakers do sound much quieter when there is no room gain!
Because it sounds much worse than measured:)
 
If the audio is used on the desktop, which one sounds better?
 
hello, may I ask how did you train or study to become moondrop's acoustic engineer? I really like Moondrop S8 back then and find other Moondrop products to be great sounding too.
 
You not have to like the kh80 but its a standart like a meter or a gallon or a joule or a newton.
You can say its boring, but thats like saying a gallon is boring.
 
hello, may I ask how did you train or study to become moondrop's acoustic engineer? I really like Moondrop S8 back then and find other Moondrop products to be great sounding too.
In 2011, when I was still in high school, I was study diy headphones and sell to students at school, about the time I started to go to college and now the boss of the moondrop and other entrepreneurial production of headphones, and then failed, the boss of the moondrop continue to persist, I went out to work for a few years, and finally returned to work in 2018, during the time, I studied the acoustics foundation in depth, handled some cases, as well as attended some university courses in acoustics, before finally becoming an acoustic engineer.
 
You not have to like the kh80 but its a standart like a meter or a gallon or a joule or a newton.
Compared to the speakers I have listened to in the studio and listening room, kh80dsp does not seem so standard, the lack of low frequency, and the sound image sounds thin, I used it for testing, because neumann dsp speakers after precise frequency response and phase calibration, it reduce the cost and time about anc testing,because we are developing and manufacturing anc headphones,need for stable and reliable test conditions.
 
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