NEED RESEARCH HELP FOR AN EXPERIMENT! (got stuck)

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Maxim Didur

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Oct 13, 2023
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Hello guys! So all we know problems of cheap microphones, but why is it so? I recently got this questions and got stuck on them, so I think this is the best place to ask them.

1) Why on a piece of paper can the Frequency Response, Diaphragm Size and Material of two microphones be almost the same, but in reality they sound completely different?

2) Why are cheap microphones so sensitive to sibilants?

3) Why do cheap microphones have very bad high frequencies, especially if you try to interact with them in any way?

4) Why are cheap microphones insensitive to low frequency transients?

5) What is diaphragm tension measured in and how do you measure it?

6) Why do cheap microphones have high levels of self-noise?

7) Why are cheap microphones less sensitive to low frequencies?

8) What are DETAILS (I mean what is it), what is responsible for capturing those details and why do cheap diaphragms record few of these "DETAILS" of the source? (THE MOST IMPORTANT QUESTION)

9) If small diaphragm are more sensitive to transients, does it mean that as smaller diaphragm as it more sensitive to transients? The same related to for large diaphragm microphones which are more sensitive to details?

10) Why do some cheap mics have a limited frequency range? And how can it have a limited range if the manufacturer writes that the range is 20-20kHz?

11) What is responsible for forming microphone frequency response, why certain microphones have certain frequency response?

(Please don't reply that they are cheap, tell me in depth specifically why this is so in microphone construction and why, you can answear any question the answear for u know)
 
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1- Because almost all microphone manufacturers cheat with their frequency response graphs!
2- A lot of manufacturers of cheap microphones use a K67-style capsule without frequency correction.
3- See 2.
4- Because they use small and stiff membranes.
6- SDC capsules produces a lower output than LDC capsules. Electret capsules are in general more noisy than external polarized capsules, especially if they have an internal FET inside the capsule.
7- See 4.
9-In general for a SDC microphone it is easier to follow fast transients, because the membrane has less mass.
10- Because they use the cheapest crappy microphone capsules. And again: most (cheap) microphone manufacturers are lying!

As always: you get what you pay for!
 
Hello guys! So all we know problems of cheap microphones, but why is it so? I recently got this questions and got stuck on them, so I think this is the best place to ask them.

1) Why on a piece of paper can the Frequency Response, Diaphragm Size and Material of two microphones be almost the same, but in reality they sound completely different?
pattern.... sound fields are 3 dimensional, typical response plots are 2 dimensional.
2) Why are cheap microphones so sensitive to sibilants?
probably the active circuitry
3) Why do cheap microphones have very bad high frequencies, especially if you try to interact with them in any way?
perhaps its difficult?
4) Why are cheap microphones insensitive to low frequency transients?

5) What is diaphragm tension measured in and how do you measure it?

6) Why do cheap microphones have high levels of self-noise?
cheap active devices
7) Why are cheap microphones less sensitive to low frequencies?

8) What are DETAILS (I mean what is it), what is responsible for capturing those details and why do cheap diaphragms record few of these "DETAILS" of the source? (THE MOST IMPORTANT QUESTION)

9) If small diaphragm are more sensitive to transients, does it mean that as smaller diaphragm as it more sensitive to transients? The same related to for large diaphragm microphones which are more sensitive to details?
less mass is easier to wiggle...
10) Why do some cheap mics have a limited frequency range? And how can it have a limited range if the manufacturer writes that the range is 20-20kHz?

(Please don't reply that they are cheap, tell me in depth specifically why this is so in microphone construction and why, you can answear any question the answear for u know)
because they are cheap.....

JR
 
Hello guys! So all we know problems of cheap microphones, but why is it so? I recently got this questions and got stuck on them, so I think this is the best place to ask them.

1) Why on a piece of paper can the Frequency Response, Diaphragm Size and Material of two microphones be almost the same, but in reality they sound completely different?

2) Why are cheap microphones so sensitive to sibilants?

3) Why do cheap microphones have very bad high frequencies, especially if you try to interact with them in any way?

4) Why are cheap microphones insensitive to low frequency transients?

5) What is diaphragm tension measured in and how do you measure it?

6) Why do cheap microphones have high levels of self-noise?

7) Why are cheap microphones less sensitive to low frequencies?

8) What are DETAILS (I mean what is it), what is responsible for capturing those details and why do cheap diaphragms record few of these "DETAILS" of the source? (THE MOST IMPORTANT QUESTION)

9) If small diaphragm are more sensitive to transients, does it mean that as smaller diaphragm as it more sensitive to transients? The same related to for large diaphragm microphones which are more sensitive to details?

10) Why do some cheap mics have a limited frequency range? And how can it have a limited range if the manufacturer writes that the range is 20-20kHz?

(Please don't reply that they are cheap, tell me in depth specifically why this is so in microphone construction and why, you can answear any question the answear for u know)
Not all cheap microphones have the issues you described. Line Audio CM4 for example is one of the best mics i've ever used. Alctron MC410 and Behringer B1 are amazing mics if you know how to eq k67 capsule. Takstar CM60 is insane having the price in mind. If anyone has any of the mentioned issues with any of these i'd say it's their production skills need to be adressed.
 
2) Why are cheap microphones so sensitive to sibilants?
The main reason is sibilant mics are more pleasant than flatter ones one the first imprssion.
Since buyers do not spend enough time to assess teh real quality of mics, they tend to favour the sibilant ones; manufacturers take advantage ot it.
Flattening the HF respnse takes some effort, more labour and more QC.
3) Why do cheap microphones have very bad high frequencies, especially if you try to interact with them in any way?
See 2
4) Why are cheap microphones insensitive to low frequency transients?
"low frequency transients" is an oxymoron; care to elaborate?
5) What is diaphragm tension measured in and how do you measure it?
Various methods, from wet finger to ripple assessment to dynamometric measurements in calibrated jigs.
Check 3D-Printed Diaphragm Tensioning Jig
6) Why do cheap microphones have high levels of self-noise?
Not a direct answer to your question, but the smaller the diaphragm, the higher the noise. When the diaphragm area is doubled, the output increases by 6dB, but noise increases only by 3dB.
Thermodynamics at work. Of course, bad design of the head amp adds to the problem.
7) Why are cheap microphones less sensitive to low frequencies?
LDC have better LF response than SDC.
8) What are DETAILS (I mean what is it), what is responsible for capturing those details and why do cheap diaphragms record few of these "DETAILS" of the source? (THE MOST IMPORTANT QUESTION)
When you understand the role of damping and tuning of the capsule, you'll have the answer.
9) If small diaphragm are more sensitive to transients, does it mean that as smaller diaphragm as it more sensitive to transients? The same related to for large diaphragm microphones which are more sensitive to details?
Please rephrase.
10) Why do some cheap mics have a limited frequency range?
Bad design.
And how can it have a limited range if the manufacturer writes that the range is 20-20kHz?
Range means nothing if it is not accompanied with the limits. How down is the level at 20kHz? 3dB, 10dB, 20dB? Thta makes a lot of difference.
 
Hello guys! So all we know problems of cheap microphones, but why is it so? I recently got this questions and got stuck on them, so I think this is the best place to ask them.

1) Why on a piece of paper can the Frequency Response, Diaphragm Size and Material of two microphones be almost the same, but in reality they sound completely different?

There are many factors, but I will describe a limited set of dominant factors.

Mic frequency response measurements are taken on-axis, with the source at varying distances from the capsule.

The frequency response of off axis sound sources, and sources rear of a mic, may vary greatly between mics that have similar on axis response.

Differences in capsule, circuit, resonant qualities of the mic body, may also lead to differences in proximity effect between mics. This means that similar response may be shown between two different mics tested with a sound source at matching distances, and yet low end may fall off rapidly with one mic but not the other when increasing source distance.

Capsules and assembled mic systems also do not have the same directivity across frequency, which greatly impacts on and off axis pickup, as well as psychoacoustic perceptions. Frequency directionally greatly effects the amount of the source versus surrounding environment that you perceive to be represented by the mic.

On axis measurement also doesn’t fully represent time domain qualities such as head basket and body resonance.

Frequency charts also do not well represent variance of harmonic distortion and resulting intermodulation distortion over amplitude level.

2) Why are cheap microphones so sensitive to sibilants?

This is a bit of an over generalization.

Historically, a dual backplate type condenser mic capsule modeled after a Neumann k67 is theoretically easier to achieve better quality manufacture at cheaper price.

A k67 was designed with a high end boost and circuit reduction of that boost, as a form of pre-emphasis, to lower noise floor.

Copy manufacturers would to attach this to circuits that don’t tame the high end of the capsule. It has a superficial impressive quality to the untrained ear, and that is cheapish to achieve.

Add this to circuits with tube and transformer combinations that tend to add distortion, and the result can be distorted sibilant regions of a recording. Since the sibilant region then has harmonics associated, it becomes difficult to just eq it down.
3) Why do cheap microphones have very bad high frequencies, especially if you try to interact with them in any way?

I just touched on it in the last response. Another reason is that poor quality manufacturers sometimes leave very slight amounts of metal dust or other environmental grit inside the mic capsules. Poor design of body materials is another.

4) Why are cheap microphones insensitive to low frequency transients?

If we are talking condensers, over tensioning diaphragm so that it’s most sensitive at a higher resonant pitch than it should be. Improper relationship between the mass of the air inside the capsule and the mass of the diaphragm. Transformers that are poorly designed and bandwidth limited.
5) What is diaphragm tension measured in and how do you measure it?

Diaphragm tension is achieved as a byproduct of manufacture. It is confirmed by various methods. A mic capsule can be wired to a standard head amp, and can be tested in an anechoic chamber. It can be tested in closed tubes of various lengths. It can be tested by measuring variance in capacitance value over a range of voltage applied to the capsule.

6) Why do cheap microphones have high levels of self-noise?

Less sensitive parts, improper design, death by a thousand cuts.
7) Why are cheap microphones less sensitive to low frequencies?

I think that one is above already?
8) What are DETAILS (I mean what is it), what is responsible for capturing those details and why do cheap diaphragms record few of these "DETAILS" of the source? (THE MOST IMPORTANT QUESTION)

see above
9) If small diaphragm are more sensitive to transients, does it mean that as smaller diaphragm as it more sensitive to transients? The same related to for large diaphragm microphones which are more sensitive to details?

It doesn’t mean that because size of the diaphragm isn’t the only factor that controls sensitivity. LDC aren’t more sensitive to details either.
10) Why do some cheap mics have a limited frequency range? And how can it have a limited range if the manufacturer writes that the range is 20-20kHz?
High frequencies have less energy, and it takes an efficient transducer to convert them to electricity without loss. That costs money to create, which may not line up with a company’s profit plan.
(Please don't reply that they are cheap, tell me in depth specifically why this is so in microphone construction and why, you can answear any question the answear for u know)
Personally, I got a little burnt out going through these points. You can go deeper for sure, especially if your question is actually meant to go fully into various mic topologies.

I think some of your questions are predicated on vast over generalizations, which I don’t necessarily agree with in every case. Rather than get deep into semantics, I have tried to limit my response to the root of “what I think you meant” in those cases.
 
I would simarize that most cheap OEM mics are replicas of existing stuff mashed up together without thinking which part plays what role. There is rarely serious issue with any particular component but how they are used.

The whole hell breaks lose when uneducated engineers try to come up with their own design like with BM800, or Apex 460. Everything that could go wrong will go wrong like with these two. And again it wasn't the parts necessarily but how they were used.

It can be as simple as wrong circuit with wrong capsule, wrong value of just one capacitor in feedback network, wrong tube like 12ax7 instead of lower gain tube, dirty PCB = noise, ringy, resonant, reflective headbasket.

Needless to say, many expensive mics suffer from the same issues.

Somehow Taylor Swift's mic of choice is Avantone CV12 which is nothing more than re-branded Apex-460 and no one seems to care when it's Taylor Swift who uses it. Maybe because engineers who record Taylor and her self know what they are doing. Back to basic production techniques...
 
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"Maxim Didur said:
10) Why do some cheap mics have a limited frequency range?

Bad design."

I would add - SM57/58 is both a cheap mic, and has very limited FR, is sm57 a bad mic?
FR of SM57/58 is limited, but useful, which makes them more or less one-trick ponies. When used as intended they provide good performance for the money, but they are easily outshined by many other mics.
As I said earlier, I'm not a fan of SM57, because I have several mics that work better in a recording situation, or even sometimes live, if I have confidence that they will be handled with care.
As a vocal mic in a live situation, I can't complain about te 58, it's quite often what I'm given to sing in. I tend not to mix activities; when I'm on stage I don't interfere with the SE.
In some situations, I bring my own mics. My favourite for many years was a Samson S12, but now I prefer the Zoom SVG6.
 
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1- Because almost all microphone manufacturers cheat with their frequency response graphs!
2- A lot of manufacturers of cheap microphones use a K67-style capsule without frequency correction.
3- See 2.
4- Because they use small and stiff membranes.
6- SDC capsules produces a lower output than LDC capsules. Electret capsules are in general more noisy than external polarized capsules, especially if they have an internal FET inside the capsule.
7- See 4.
9-In general for a SDC microphone it is easier to follow fast transients, because the membrane has less mass.
10- Because they use the cheapest crappy microphone capsules. And again: most (cheap) microphone manufacturers are lying!

As always: you get what you pay for!
Wow, thank you! Does the uasge of K67-style capsule means that the same model of microphone will have diffrent frequency response because they dint have frequency correction? How frequency correction is done?
 
Wow, thank you! Does the uasge of K67-style capsule means that the same model of microphone will have diffrent frequency response because they dint have frequency correction? How frequency correction is done?
Yes. This is measured frequency response of circuit of a vintage u87. Just the circuit, not the capsule. U87 has basically a built in EQ to compensate for capsule's (k67, k87) high end boost, and reduce some low end. U67 is not much different.

You can make this same curve in your EQ of choice and use with k67 based mic as a starting point. Have in mind most k67 replicas have more high end boost than original Neumann's, so just use some more attenuation in the high end.

Read this
https://audioimprov.com/AudioImprov/Mics/Entries/2014/2/7_Mic_Electronic_Eq_Pt.1.html
On Audio Improv site you have most answers to the questions you asked.
 

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That seems like a myth. Good quality SDC have no problem with LF response.
I didn't write they had "problems", just that considering the basic laws of physics at work, i.e. mechanical resonance and smaller capacitance, SDC's have a higher LF cut-off frequency than LDC's. Of course there are exceptions and many possible tricks.
Like with loudspeakers, it is quite possible to have a 5" speaker having the same LF cut-off than a 15", but at the cost of several other parameters.
 
Hello guys! So all we know problems of cheap microphones, but why is it so?

Three letters: MIC

Made In China

The technical issues behind this are interesting, but incidental.

It is important to understand how chinese manufacturing works and how it impacts the western companies making similar products. This is not specific to microphones, but general.

It starts with a product that comes in from the west (or in case of microphones from East Germany - Gefell and Japan for the cheap electrets).

It is possible an assembly line is build (like it was the case in the #797 Military Electronics factory), or a western product is simply copied.

Initial products are made to original standards and usually match or at least come close to the originals, but they are usually copies made absolutely verbatim, without understanding what is being copied or made. This gave rise to the technical term "chinese copy".

The next step is that someone makes a "domestic chinese" version, which substitutes expensive imported materials with approximate equivalents sourced locally.

Because there is no understanding of the detailed workings these "copies of copies" usually are worse than the originals, but they look the part and work okay, often good enough to still sell in the west as lower cost alternatives to the originals. Technical data and graphs are naturally copied also, from the original, not actually derived from the product (in fact, the factory may not even know how to perform these tests)

This now prompts several further developments.

The manufacturer of the original item and the western customer are now under price pressure and will likely be forced to introduce "value engineered" (read cheapened) versions of their products.

Now that it is possible to make the whole item domestically, multiple factories start to make copies of the copies of the "chinese copies" we started with. These factories often apply further aggressive "value engineering" chinese style.

So now we have the western original ($$$$$/*****), the chinese made authorised or at least accurate copy ($$$$/*****), the chinese local copy ($$$/***), the "value engineered" western branded item ($$$$/***) and the various copies of the chinese local copy ($$/**).

They all look very similar and they all work, but of course the lowest priced are not as good. BUT, for many less sophisticated users the lowest priced items may actually be good enough, or they simply do not know better.

As a result the original western brand first tries to compete through innovation, but that is difficult, expensive and who knows if the new innovative item will sell even as well as the original. Because competing becomes hard the western company often goes out of business, at which point a chinese company buys the brand and IP portfolio at fire sale prices and starts making low end garbage under the original prestigious brand name.

So now every item in the market that survives is a value engineered chinese product under a famous brand ($$$/**) and a smattering of low end chinese copies of copies of copies ($$/**).

As now all products in the market are garbage and nobody innovates and everyone copies each other, the only means to compete are by price. To lower price it is necessary to lower cost. As there is still a need to "look the part" the only way to lower cost is cheapen the materials and insides of the products.

Now someone in the West, like an ex-employee of one of the western companies that folded or exited the market will likely revive the original product or something very similar and may even be able to reacquire the original brand. These products will be very expensive, small volume and are basically artisanal for those who can ($$$$$$[$]/****[**]).

Meanwhile the chinese made cheap products get also more expensive due to inflation but stay relatively cheap, yet their quality gets lower and lower and lower.

To return to microphones, what may have started with a good copy of a 32mm externally polarised capsule and good electronics, now ships with a garbage 16mm electret capsule and badly implemented cheapened electronics. What started with nice machined Alu now uses metalised plastic or paper thin extruded Alu. It still looks nice though and many are fooled.

Even if Chinese Factories were not experts to in having their sales staff post large number of positive shill reviews, enough people will get these mic's, find them better than what is build into the wired headset that came free with their mobile phone and give good reviews.

And then someone on the internet asks "Why is it that cheap microphones are no good?"

Thor
 
Three letters: MIC

Made In China

The technical issues behind this are interesting, but incidental.

It is important to understand how chinese manufacturing works and how it impacts the western companies making similar products. This is not specific to microphones, but general.

It starts with a product that comes in from the west (or in case of microphones from East Germany - Gefell and Japan for the cheap electrets).

It is possible an assembly line is build (like it was the case in the #797 Military Electronics factory), or a western product is simply copied.

797 made mics for decades that were not clones of existing designs.

German condenser history started directly with making copies of the Western Electric 47A.
Initial products are made to original standards and usually match or at least come close to the originals, but they are usually copies made absolutely verbatim, without understanding what is being copied or made. This gave rise to the technical term "chinese copy".

“Without understanding what is being copied or made.”

That’s going out on a limb.

And “chinese copy” is a “technical term”?
The next step is that someone makes a "domestic chinese" version, which substitutes expensive imported materials with approximate equivalents sourced locally.

Because there is no understanding of the detailed workings these "copies of copies" usually are worse than the originals, but they look the part and work okay, often good enough to still sell in the west as lower cost alternatives to the originals. Technical data and graphs are naturally copied also, from the original, not actually derived from the product (in fact, the factory may not even know how to perform these tests)

There were many US mic modders in the 90s who would use mics based on k67 capsules, and not correct the top end. It is not exclusive to China at all, and is an idea that was trendy at the time some of the first Chinese condensers started getting distributed in the US.

You are very wrong to think that these companies don’t have test equipment, don’t know how to do tests, and don’t know how things work.

You have cast a net as wide as an entire country.
This now prompts several further developments.

The manufacturer of the original item and the western customer are now under price pressure and will likely be forced to introduce "value engineered" (read cheapened) versions of their products.

Now that it is possible to make the whole item domestically, multiple factories start to make copies of the copies of the "chinese copies" we started with. These factories often apply further aggressive "value engineering" chinese style.
You are overlooking world economic forces that subjugate various populations, and make certain types of manufacture high cost or basically illegal in the West.

So now we have the western original ($$$$$/*****), the chinese made authorised or at least accurate copy ($$$$/*****), the chinese local copy ($$$/***), the "value engineered" western branded item ($$$$/***) and the various copies of the chinese local copy ($$/**).They all look very similar and they all work, but of course the lowest priced are not as good. BUT, for many less sophisticated users the lowest priced items may actually be good enough, or they simply do not know better.

This really is not answering the original post, it’s just a soap box at this point.
As a result the original western brand first tries to compete through innovation, but that is difficult, expensive and who knows if the new innovative item will sell even as well as the original. Because competing becomes hard the western company often goes out of business, at which point a chinese company buys the brand and IP portfolio at fire sale prices and starts making low end garbage under the original prestigious brand name.

What “original” western mic brand are you even talking about at this point?

A company like AKG was running themselves into the ground with increasingly bad design and less value far before chinese mics came to the west in a widespread way. Neumann as well.
So now every item in the market that survives is a value engineered chinese product under a famous brand ($$$/**) and a smattering of low end chinese copies of copies of copies ($$/**).
Not even close to reality.
As now all products in the market are garbage and nobody innovates and everyone copies each other, the only means to compete are by price. To lower price it is necessary to lower cost. As there is still a need to "look the part" the only way to lower cost is cheapen the materials and insides of the products.

Now someone in the West, like an ex-employee of one of the western companies that folded or exited the market will likely revive the original product or something very similar and may even be able to reacquire the original brand. These products will be very expensive, small volume and are basically artisanal for those who can ($$$$$$[$]/****[**]).

Meanwhile the chinese made cheap products get also more expensive due to inflation but stay relatively cheap, yet their quality gets lower and lower and lower.

To return to microphones, what may have started with a good copy of a 32mm externally polarised capsule and good electronics, now ships with a garbage 16mm electret capsule and badly implemented cheapened electronics. What started with nice machined Alu now uses metalised plastic or paper thin extruded Alu. It still looks nice though and many are fooled.

Even if Chinese Factories were not experts to in having their sales staff post large number of positive shill reviews, enough people will get these mic's, find them better than what is build into the wired headset that came free with their mobile phone and give good reviews.

And then someone on the internet asks "Why is it that cheap microphones are no good?"

Thor
I think this comment is dripping in over generalization and stereotype. In that, it edges up on bigotry and racism. It is using the original post as an excuse to engage in a diatribe that doesn’t really answer the original question.

All you need to do is go browse eBay to be reminded of decades worth of US and European made mics that are absolute junk, and far worse than what is being criticized here. Many forgettable brands and models apparently.

And no, the previous replies are not “incidental”. There are plenty of crappy mics made all around the world, and through history.
 
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The issue with bad sounding mics is not about the fact they are made in China, nor the fact they are cheap. Bad mics are made by people who don't know what they are doing.

- 797 audio is a chinese military contractor, and makes parts for their space program. Their capsules are of exceptional quality, and costed 30$ a piece last time i bought from them. Off course it might just happen you still don't like how they sound, and that's ok.

- Peluso is an American company and they use 32mm (wrong size) chinese capsule backplates that probably cost 5$ a piece at most, sell them for hundreds of dollars, and many of them have wrinkled diaphragms. IMHO they have no idea what they are doing, and their mics sound nothing like what they try to represent. Which is not surprising as they use 32mm k67 capsules in u47 inspired mics.

- Cathedral pipes is another US company that make magnificently sounding mics, all by hand, but have capsules with collapsing diaphragms, glue that comes lose, and backplates which are not properly cleaned.

- Shure is a magnificent company that has made remarkable microphones throughout the years, keeps pushing the boundaries with new concepts all the time, and has some quite inexpensive microphones. But they don't have 47 number on any of those mics, and none of the mics look like u87. So an average Joe would rather buy a rubbish mic from Peluso than from Shure.
 
Should we move this entire thread to the Bewery?
Typical reply from you whenever the discussion doesn't go in a direction you'd like it to. The OP's question is complex, and can't be answered by quoting a specific formula from a favorite theory book.

Like it or not, half of the stuff here has to do with marketing and non-technical misconceptions. I'll refrain from replying further in this thread as i know what discussing with you looks like.

It seems to me you will have to ban me eventually from this forum, as you can't seem to differentiate between healthy discussion and your personal preferences. Which is unfortunate for you as an admin. I'll do you a favor and invite @JohnRoberts to threaten to close the thread, so you don't have to.
 

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