Smartphone vs. Real Meters for Sound and Light Measurement?

[@hudibaba]

yes please make one one for the magnetic sensor

[@MrManatres]

In my country, argentina, I had seen some "qualified" technicians evaluate MRI installations only with the magnetic sensor on the phone hahaha

[@Random_4400]

Yes

[@franciscoj.a.5294]

@@MrManatres joderme, me imagino que no de dalde

[@HighVoltageMadness]

@@MrManatres lol

[@MrManatres]

@@franciscoj.a.5294 no me acuerdo el nombre del señor, pero son de radiofisica los que van a evaluar que las lineas de gauss no lleguen a las salas de espera en las clinicas o sectores asi

[@LookingGlassUniverse]

I find these side-by-side comparisons you do very helpful- the results are so surprising! Thank you for doing them, and I'd love to see more

[@brainiac75]

Glad you like it. Guess there is some consumer information value for videos like this. Will have to try the magnetic sensors too :)

[@m80116]

The trouble with dB meter apps I tried is that by default they all show different levels. I already had the app shown in the video before and was considering it as one of the most accurate (with no calibration). Probably despite the limited functionality the MM sound meter function might still be more reliable than apps which rely on internal hardware (fine if you have top smartphones, far less if you have 2nd and 3rd tier devices).

[@pvic6959]

@@brainiac75 what app is this? Im not sure if it was mentioned and i missed it. I want to roughly measure the brightness of a flashlight i have but have nothing to measure with. It doesnt make sense for me to guy a meter for this one off thing

[@TheExileFox]

It should be noted however that the smartphone will do horribly with certain sounds. It's hard to describe accurately because i'm not entirely sure what frequencies this is happening at. I have never been able to catch it when carrying a proper sound meter. Quite annoying as it's quite common to run into these sounds at random times. If anyone has more details on these "difficult to record sounds" I would like to learn more about them.

[@colourbasscolourbassweapon2135]

my subwoofer dual 18inch plays at of the level of 138db ngl@@brainiac75

[@daringd3lta574]

I would love to see the smartphone compared to a real gaussmeter! That would be awesome!

[@Eneicia2011]

Right???

[@jennalove6755]

uhh technically they have one in them because of the digital compass

[@daringd3lta574]

@@jennalove6755 Yes

[@Ryan_Smyth]

LOL! I was just thinking that! I have a 5% Gauss meter (the price difference for a 1% Gauss meter just isn't justifiable for hobbyists like me - they're crazy expensive) so I may just give it a shot & try. And God knows I have enough magnets! I spend way too much money on them. :D

[@sashabagdasarow497]

@@Ryan_Smyth have you tried it?

[@Yossus]

In my Physics lessons, I occasionally use the phyphox app, which lets you capture the raw output of all the phone's sensors. It's quite amazing how accurate they can be, and definitely enough for schoolwork! I've had good experiences with the magnet sensors as well.

[@ziginox]

+1 for phyphox!

[@TheSwaroopB]

phyphox FTW!

[@CrooningRevival365]

I always pull out that app when I’m in a tall elevator:p

[@Cyberfly100]

+1 for phyphox! Check how the pressure changes by just moving the phone a few meters up or down. Or use the pressure sensor on an airplane to detect when the toilet is flushed. The accelerometer or noise spectrum analyzer can tell you the frequency of vibrations in your 3d printer. Great app.

[@dvdcd]

As a live audio engineer, having a spectrum analysis and SPL on your phone if you don't have anything else has seriously saved my butt a couple of times

[@neilg322]

Really interesting, i have wondered about the sensitivity of smartphone sound apps, especially as a sound level meter and where they max out, at concerts etc. A magnetic flux test would be good to see too.

[@theirisheditor]

I'd love to see the sound meters tested at different volume levels. The main issue I found testing different Apps is they vary a lot above around 90dB. Generally the only time I open a sound meter App is when I'm at a loud venue, etc.

[@mindtraveller100]

@@scorpioassmodeusgtx1811 Nothing beats a dedicated microphone.

[@snowdaysrule]

I really appreciate this one. I've been using the sensor capabilities of my smartphone lately and was wondering just how meaningful the output was.

[@CnCDune]

Would be interesting to see older phone models in similar tests if possible, not just current gen ones.

[@brainiac75]

Will consider it. I have access to an S10+ and iPhone 7 too.

[@CamcorderHomeVideos]

@@brainiac75 Do you prefer iPhone, Samsung, or Pixel?

[@rebane2001]

And a modern but very cheap phone would also be fun to throw into the test

[@TeslaLiam]

@@brainiac75 Yes, very good idea. I don't think a test with 10 years old phones would matter. Most people have there phone no longer than 2-4 years.

[@TeslaLiam]

@@rebane2001 Absolutely!

[@JoshuaPlays99]

I've always loved testing the sensors in my phone and have wondered how accurate they really are. This video was great to see and I would definitely like to see a video on the magnetic sensor

[@TheSwaroopB]

This is a brilliant video!! Thanks for comparing. For anyone looking for the apps used in the video: Lux Light Meter Photometer Pro Decibel X - Pro Sound Meter (Can't share Play Store links since the comments get auto-deleted)

[@ashyouknow7420]

Thank you bro!! I was really searching for a comment like this. I literally searched "app" in the finder of the browser lol

[@Guardian_Arias]

The suite of sensor on some smartphones are absolutely amazing. I used to use the barometer on my old Galaxy S5 to help me troubleshoot Aircraft Cabin pressurization issues since the phone would often have a greater degree of accuracy than some older pure analog and pneumatic based pressurization systems.

[@CoherentPhoton]

Thank you for this comparison video. I wonder if it would be possible to "calibrate" some of these functions? If a smartphone app had an option for calibration and you had access to a high quality instrument to use as a calibration standard, that would be awesome! Please make a video for the magnetometer :)

[@jasonpatterson8091]

I do know that the pressure meter in a Samsung Galaxy is surprisingly sensitive, and the sensor menu is awesome. It can measure altitude changes of less than one meter based on atmospheric pressure, for instance, less than one pascal.

[@chstoney]

I was working in a laboratory with sound-measuring equipment (SQuadriga 4) and I did a comparison of one of these sound-measuring apps back then too. And I was really surprised by how close the measurements of the phone were to it.

[@kartikahlawat413]

Yes I do wonder how good is the magnetometer on a cell phone and can only expect a detailed vedio from you............btw love watching your vedios ❤

[@brainiac75]

Thanks - will need to find the limits of that sensor ;) More to come in 2023!

[@CamcorderHomeVideos]

@@brainiac75 Yay!

[@user-zv2gr3tu1l]

@@brainiac75 excited

[@Redstoner]

Try the Photone app which uses the camera and a piece of paper to diffuse the light coming in

[@Rararawr]

The phone was closer than I expected. I have the same app on my phone to play around with. Going to an incredibly loud concert tomorrow so it'll be fun to see roughly how loud it really is

[@simonmikkelsen]

What is the name of the app?

[@Rararawr]

@@simonmikkelsen DecibelX

[@vjay4297]

Multimeter is calibrated for use in handheld position, and directing the microphone to speaker may have boosted the response as it may be designed/calibrated to sound coming from top side.

[@usy-]

Nice video! Although I do believe you could have mentioned that the readings you obtained are accurate but only for your specific smartphone model (and maybe even unit!) and app used, as there can be great variance between smartphones and even the app used for the SPL reading, for example my phone shows about 10dB below my SPL meter at 1khz using the same app and same weighting, and as well as this the frequency response of the phones microphone is likely not flat, and therefore it wont measure all of the frequencies accurately. Oh and also, if you do want to perform this test on more phones, I have heard that the NIOSH app for iPhones is relatively "accurate", and ive checked my iphone 6s plus against my SPL meter and it was within a few decibels.

[@barrupa]

From a quick google search, the TMD4912 light/proximity sensor manufactured by AMS seems to be an infrared based sensor and it's primary function is indeed to be a proximity sensor. It just so happens to be an optical light sensor specialized in sensing infrared light. Interesting to see the sensor choice by Samsung now knowing that it is indeed made to be used for both purposes.

[@michel_dutch]

Of course we would like a video that checks out its magnetic capabilities, would be awesome! Also, I'm curious if your chemical element collection has grown so that you could make another attraction/repelling video? Really liked that series too. Best wishes for 2023!

[@glbernini0]

Which SPL app was used on the phone? Make & model of phone as well, we shouldn't assume all phones & apps are equally good, THANKS!

[@sebbes333]

3:15 Something seams wrong with the leftmost meter, it is 10x lower than the other. Is it set in the wrong mode or something (like measuring "deci lux" or something strange like that (deci = 10))? The middle meter, I can't know if it says 1,06 lx or 106 lx? Or do they ACTUALLY measure that much differently in red light?

[@guffyscotland9605]

You would not believe it but I was literally thinking about this a few hours ago! I got new headphones and know they're good to 106db (but obviously my ears aren't) and questioned if my phone would even be accurate enough to read that high reliably. Fantastic time to drop this video! EDIT: Just finished the video! I am absolutely astounded by the results, I cannot believe that the *very* multi-purpose smartphone held some level of competency in metering. Obviously I wouldn't trust my hearing or headphones with it, but the fact the range is so broad and remarkably accurate does give me confidence in knowing that I was actually being rather "scientific" in my methods where I relied on a specific Hz (tuning belts on a 3D printer) to get correct tension. This is a really valuable video!

[@DustyTheDog]

9:03 I can hear something happening here. It's very high pitched, but it's there. This is the reason I hated being around any CRT screens.

[@MeriaDuck]

6:30 even if the pun was not intended, I laughed 🤣

[@HuskyMan77]

2:33 That's pretty interesting, on my phone (which is a Galaxy S8) it has both the light sensor and the proximity sensor separately. I also wonder if the light sensor being under the screen in the Galaxy S21+ affects the light readings a little bit, on my S8 it's on the top bezel.

[@fgbhrl4907]

You can get cellphones / tablets that have RGB-IR light meters in them -- I've worked on designing some of them. They are calibrated at the factory with light sources (at least, the products I worked on). The use of an RGB light sensor was to change display color temperature -- eg, it would be cool blue under flourescent lights, and warm under incandescent.

[@todayonthebench]

Smart phone apps though have the big downside of having to rely on whatever sensors the manufacturer decided to put into the device. So it could vary a lot. However, I am not the slightest bit surprised over the spectrum being fairly spot on. The frequency references a phone has access to is fairly decent. Very few quartz oscillators are worse than 0.01% absolute accuracy. However, having access to time things from this oscillator isn't always available, but the audio chip itself will deliver its samples using that oscillator as its own reference. So one can be very certain that if the ADC provides 44800 samples/second that it will be fairly accurate. But exact audio amplitude will depend on a lot of things. Both the manufacturing tolerances of the microphone, amplifier, and ADC. So it could vary a lot. Especially since absolute amplitude isn't particularly important in audio applications regardless. (as long as it is nice and linear it doesn't matter if it has a different amount of amplification.) So I am surprised about the amplitude accuracy. But perhaps they factory calibrate this, otherwise I would expect a 2-10% accuracy there alone, perhaps your phone is just above average. The magnetic sensor part could be interesting to look at. But regardless. I personally prefer using dedicated measurement tools. Both because they are often more adapted to the job, but also because they can be more trusted. (especially as far as traceable calibration goes.)

[@chassy7072]

The amount of respect i have for your work for simply putting safety warnings in your videos is ridiculous. Good work friend

[@The77Game]

11:36 the point about "the right phone model" is what i would like to see tested. Do phones generally do well or is it just the more expensive ones or certain brands? And also is it only accurate up to a certain point? This could be very useful information as i have seen people use a phone app to see if they are in an environment where they should use hearing protection. If they see this and assume a phone can measure that but it can't, people could be putting their hearing at risk.

[@redlab3488]

Awesome! I was looking for a decent soudmeter on my tablet. I've tested several but they show very different values and what's more they detect the rise of a sound but if the sound continues, the measure drops down ... Decibel X does not. One question, how can I be sure that the calibration is correct as yours on your phone ? Is it guaranteed because the app is the same or it can depend on the phone ?

[@systemdrive7970]

Again, another amazing video. I really love these side by side comparison videos. Love your videos!

[@Uberhood]

Hi Brianiac75. How did you find the light sensor service menu? I can't find it on my samsung service menu, only accelerometer and megnetometer for example. Thanks.

[@mhdm]

For anyone else wondering how to get to the "service menu" at 2:22 that one is specific to most S* samsung phones. It can be access by typing in *#0*# in the dialer (no need to actually press call, no need for a separate app).

[@handle924]

which app did you use in the video? curious how well smartphones are at measuring low-frequency noise

[@audiogek]

Not surprised, I expected the smartphone to do as good as the dedicated meters, within 1% at least. Because smartphones are basically everywhere, that means also in the hands of people with calibrated tools. And over the years a lot of apps got calibrated with those dedicated meters for a lot of phones.

[@JGnLAU8OAWF6]

Most sensors are digital and probably factory calibrated to some extent.

[@mindtraveller100]

But any smartphone lacks a dedicated high quality microphone, and that means they´re useless measuring really loud volumes. 80 dB, or maybe 90, they can do. Above that, no...

[@audiogek]

@@mindtraveller100 True! Apps use to tell you that, but now that most apps are created for advertising money I'm guessing they don't do that anymore 😏

[@mindtraveller100]

@@audiogek I tried 5 or 6 apps before, all of them only measuring up to around 80 dB. Recently i bought a cheap, and i really mean cheap, spl measuring tool. It reached 118 dB when i placed it a few inches from my studio speakers. And the price? 12 euros (around 12 dollars). Downside, only measures dBA not dBC, so no bass measuring. But for the price, i can´t complain, better than any app...

[@Dukefazon]

I regularly watch a guy who repairs all kinds of old computery stuff, sometimes CRT monitors and TVs and he uses an app to determine if the CRT is working by looking at a spectrum analizer on his phone. If the TV/monitor doesn't show a picture but the main circuit is working, he can see a peak in the monitor's/TV's operational frequency on his app, very interesting stuff.

[@ronsku57]

Very interesting topic!

[@brainiac75]

Glad you like it! I am still surprised by the end result...

[@volvo09]

Indeed! I had read about the accuracy of the light sensors in phones before when researching indoor gardening light measurements, and the tests I saw agreed with these results, for most uses the phone is just fine (with white light). I also learned how the proximity sensor worked!

[@SQ-619]

I'm pretty lazy when I comes to writing comments, but wow, this really shocked me. A dedicated multimeter was actually beaten - in some categories - by a smartphone! Truly incredible. Great job my guy, I really learned a lot from you!

[@mindtraveller100]

There is nothing "dedicated" about a multimeter measuring light or sound...

[@Lampe2020]

7:08 What app was it that showed this nice frequency graph?

[@l.mcmanus3983]

Very cool video. Neat to see the smart phone do that well for light. And that makes sense that is might purposefully be extra sensitive to infrared.

[@traisjames2]

I think you might want to look into the phone more, at 2:41 It seems to be showing RGBW channels, so maybe that gives better color reading?

[@GQuack]

Let's see if the smartphone truly is *the* ultimate portable digital multitool that can do so much more and see if that magnetic sensor really is good. If it's good enough for the built-in compass app, it could be useful for amateur work. Keep it up, Brian! And here's to a much brighter 2023!

[@Da5idc]

Excellent video - I really appreciate you taking the time to do these type of tests. It's really useful to see if apps are worth using

[@adnanmlivo5885]

I always thought that apps where way off. I guess not. Great video as always!

[@Basement-Science]

The main issue with the smartphones is that you never really know if your model is as good as another with any particular app. You'd have to test it against a reference meter for everything before you can trust it at all. Of course cheap dedicated tools can also have their issues. For example I have a lux meter that gives me pretty high readings when I shine some 400nm light on it - because the plastic in front of the sensor fluoresces and changes the color.

[@cybermaus]

7:38 Maybe you needed to change the range? Mine (dedicated) meter has separated ranges from 60-120 and 30-90

[@atonduke7612]

I'm quite surprised with how well the phone did. I'd definitely like to see you test the magnetic sensor and other sensors (compass, gyroscope, g-sensor, ...) on your smartphone.

[@Kaamszz]

Big yes for the magnetic test with the smartphone !!!!!

[@rexthewild]

To be honest… it makes sense that “ a free app from the phone” does such a good job, at least as a sound meter, since the phone has some good microphones that needs to make us sound as good as we can when speaking trough them, so an app just take the raw info from the mic and give it to us on a slick UI, what surprise me is that the proccessors on the phones can tell the frequencies of the sounds that are playing

[@GreenAppelPie]

Now I want a 50w RGB. And I’m not surprised by audio meter in the phone. I played with the capability after using a guitar app, it really is impressive and accurate. I’ve also found aircraft interiors to limit sound to safe levels

[@ashyouknow7420]

interesting. It's like seeing the world from a new perspective, isn't it?

[@CTcuber4K]

I used the decibelX app at an airshow for a eurofighter typhoon, it gave a max reading of only around 110 decibels while the actual volume was definitely in the 130-140db range. I would think phones start to struggle when the sound gets really loud, but I can't confirm that as I only have that single test.

[@christiangonzalez6945]

Considering that 110 decibels it's permanent damage zone at least its doing their job...

[@AnalogWolf]

Very well done, technically sound and you also do a great job breaking it down into terms that are easy to understand.

[@andyafk]

from \my understanding, luminosity of lux were calculated by distance of the light and the front camera of the phone might be focus closer (focal length) to the light source then the light meter that you were using

[@coriscotupi]

Good video. ...What was the sound measure app used?

[@snave494]

What app did you use for the sound tests?

[@kithpendragon]

I use "Physics Toolbox Sensor Suite Pro" to access my phone's sensors. There's a free version that I upgraded from because I liked the app so much. Both versions include access to the camera and microphones, proximity sensor and light meter, accelerometer and gravitometer, and the magnetic sensor. I'd love to see all the phone's sensors put against dedicated devices!

[@Splarkszter]

One thing to say, usually the expensive ones are accurate and don't drift much, and when they drift, some offer a life-time warranty for calibration.

[@user-cx7te6pl2h]

I appreciate you sharing this rigorous experiment. God bless you.

[@asilva781]

The a and c weightin I remember measures with mores sensitivity frequencies from 500Hz to 5000Hz. May be this is why you have very different measurements with extreme frequencies.

[@addusernamehere]

Great scientific breakdown & comparative analysis. Thank you!!!

[@pennyether8433]

What's the name of the decibel meter smartphone app?

[@cherokee131]

Decibel X

[@UtkarshAmitabhSrivastava]

Now I want a comparison between different smartphones.

[@blithegd8]

Hi Brian, merry Christmas and a happy new year~ :) I really like your videos! thanks for making them

[@brainiac75]

Hi tjop. Same to you - hoping for a great 2023!

[@blithegd8]

@@brainiac75 Thanks bro :)

[@ThaVoodoo1]

@6:40 Am I correct in saying that the speaker output power should be at 1 Watt, then measured at a 1 Meter distance from the speaker.

[@MateoPlavec]

2:47 "Not bad for a sensor meant only for adjusting the screen's brightness" This statement is only semi-accurate. On modern phones with edge-to-edge screens (especially Samsung) the luxmeter is also used for proximity detection (eg. turning off the screen when on a call and the phone is close to the ear). This is a recent change, probably because there is no room for a proper IR proximity sensor in the thin bezel. Edit: spoke too soon, you clarify later in the video.

[@johnniewalker39]

Oh wow! Didn't see that coming (no pun intended) 😄 And yes, please do a vid on the phone magnetic sensor readings. Happy New Year!

[@davpro1792]

Yes make a video about the Magnet sensor of your smartphone. Would be a very... interesting video!

[@graealex]

Halogen lamps emitting UVC? Seems highly unlikely. Filters are usually there to reflect some of the IR.

[@WilburJaywright]

Midway, I want to say, kudos for giving excellent music credits. Thanks!

[@HighVoltageMadness]

Not all phones have accurate dB sound meter. My phone seems to be capped at like 85dB and the reading is very inaccurate. It only works well on certain models of cellphones. I have tested the lux meter, magnetic sensor, barometer, gyro, and accelerometer on my phone and they were pretty good though.

[@DunOpondo]

Such tests are the reason I like Samsung flagship phones, portability and accuracy of sensors. Great video 👍🏿

[@plrodgers]

Thanks for the video, this is quite interesting. Do add more discussion and videos on other sensors available in cellular phones.

[@whitehorsept]

Yes please! Would be interesting to test the other smartphone sensors!

[@MrTurbo_]

The thing with the db meter apps is that popular phones often get their own calibration profile making them fairly accurate, while less popular phones are often waaaaaay of, making them completely useless, also dedicated db meters often do way better at very loud sounds like 110+ db because the phone mic will clip

[@ecodev15]

yes make the gaussmeter phone video ive always been surprised with the sensors in phones! samsungs older phones used to have heart rate monitors built in (mine does)

[@DEtchells]

Good video! Yes, I’d definitely like to see how good the magnetic field sensor is! (It’s probably only good for very low gauss levels though, as it’s only there to act as a compass :-/)

[@photelegy]

8:33 What's the name of this app?

[@JoshuaNicoll]

Yes there should be an IR LED near the lux sensor as that's how the proximity sensor works, by reading how much reflected IR there, at least that's how it should work. There are other kinds but that's the IR lux meter one, common on smart phones.

[@_BangDroid_]

Audio perception is very fascinating. At the threshold of hearing the distance the eardrum moves about 1 picometer, 100 times smaller than a hydrogen atom. Which opens the question, are quantum effects involved in hearing?

[@dinitroacetylen]

I hope you have a great new year with many more interesting discoveries!

[@tommiller1315]

At the start, I was thinking there is another meter to add to my collection. (Anyway, I couldn't find it for sale here in the UK). Your results have put me off getting one anyway - thank you👍

[@YTshashmeera]

Yes! I'd love to see a video covering the magnetic sensor

[@nefariousyawn]

This is probably valuable information for people that like to build their own lights for aquariums, terrariums, indoor plant growth, etc. Lights marketed for any of these specific applications tend to be more expensive.

[@johncoops6897]

Measurements for those applications cannot be made in Lux. That's because Lumens and Lux are weighted measurements that only apply to human vision.

[@AhmedDiaa98]

Thanks bro fir this professional video all informations I need are there and more, you are the best 💖👌👌

[@Andrew90046zero]

I’ve had an app that lets you use all the sensors, but for the amplitude, it says that it needs to be calibrated? But idk how i am supposed to do that if I don’t have a device that can’t already measure the db…

[@ronsku57]

Yes please make a video for the magnetic sensor on the phone!

[@wisteela]

Yes, it will be very interesting to see what the magnetism meter is like.

[@NLind]

Now watch the downloads for Decibel X and Photometer Pro skyrocket, great publicity for those apps! But I would also like to see a comparison for the magnetic sensor.

[@asteria1065]

Truee!!!

[@kmemz]

Magnetometers have been used in phones for gyroscope corrections, to limited success. I'm not holding too much hope that the magnetometer coild make an accurate reading, if it can't accurately be used to correct a gyro.

[@vgamesx1]

Sensors in phones work rather well, but the software can be very hit or miss.

[@graealex]

@@vgamesx1 Depends on what your scale for reference is. Smart phones will usually use the smallest available sensors, which are usually the last-gen stuff, but it doesn't mean that's the stuff with the lowest noise necessarily.

[@brainiac75]

I would be surprised too if the magnetic sensors are precise - especially when there are three of them. But hey, the phone surprised me for this video so worth a try ;) Thanks for watching!

[@vgamesx1]

@@graealex Noise isn't a big deal, you just do the same as what anything else does, like a DMM, take a few thousand or so samples and give an average every second.

[@graealex]

@@vgamesx1 Noise is by far the biggest problem for acceleration and gyro sensors. Without noise, you could easily implement an INS. What you are describing is just a very simple low-pass filter.

[@J0rdanXYZ]

wow I was looking for an android app for sound levels a day before you uploaded. I'm worried about my hearing after working in a nightclub for 3 years without hearing protection and I was wanting to see how loud the sound was as sometimes it feels like my ear drum is about to burst with how crazy loud it is. Worst part is I'm over at the bar and the speakers are all pointed towards the dance floor so it is so much louder when standing on it compared to the bar area. (wear hearing protection)

[@Vykori]

what smartphone are you using for testing?

[@hughbrackett343]

I took a family member for an MRI. I entertained myself the entire time I was waiting by exploring the field of the 5T magnet, that was about 20' away in another room, with my smartphone. I've tried some 'metal detector' apps and found them not useful. Magnetometers are used for underground locating but they are arranged in such a way as to cancel the ambient magnetic field thus detecting tiny anomalies. The phone of course is designed to measure the ambient magnetic field.

[@edhikurniawan]

Interesting, I just found out my phone lux sensor is on the screen side. Zenfone 6 doesn't have front camera. Tho I question the accuracy lol. It would be interesting to see the frequency response of the mic, not just dB/ SPL meter.

[@raihanlazuardi6632]

Yes! Please make a video about the magnetic sensor.

[@twycross3]

Wow yes! Please do a magnetism smartphone VS Gauss meter

[@beedebawng2556]

@Brainiac75 What were the smartphone apps you were using for sound measurement?

[@dcallan812]

Smart phones really are getting smart. Great video 2x👍

[@brainiac75]

Yeah, they sure are getting expensive too. But maybe I understand the price a little better after making this video. They are packed with sensors of decent quality :) Thanks for the early watch!