Building a quality USB-C microphone

in this video we're going to be building a fully diy microphone that not only has an incredibly unique retro aesthetic but is entirely self-contained featuring a built-in shock mount adjustable boom arm preamp and a usb type-c interface and of course this being a diy perks project it also features a premium sound quality that's so good that it can compete against professional-grade microphones that cost literally 30 times as much let's get to it microphone design is more of an art than a science which is why professional models can often cost thousands of dollars and some are revered decades after their debut of course cheap microphones are readily available in the devices we use every day but their sound quality leaves a lot to be desired when it comes to anything other than communication partly due to the limitations posed by the physical size of their microphone capsules which are generally far smaller than those used in professional equipment remarkably though some of these large capsules aren't actually that expensive and it's possible to buy the exact same capsule that's in this 500 microphone for example for just 12 directly from the manufacturer which is a huge saving if we can process the signal as well as the original circuitry does this particular capsule is a jli 2555 and is a permanently polarized type which makes it fairly easy to get a sound signal from it simplifying the build process quite significantly because the membranes in microphones of this type have such a weak output though this output needs to be strengthened before anything can be done with it on a lot of small capsules this extra strength is provided by an internal transistor soldered to a pcb on the back but the much larger jli microphone leaves it up to the designer to add one presumably for customizability thankfully suitable transistors are readily available and hooking it up just requires the leg labeled as gate on the data sheet to be soldered to the capsule's central tab like so the leg next to it won't be used so i just chopped it off to avoid confusion leaving the remaining legs known as drain and source because of the way the transistor will work in the circuit i'm going to refer to these legs as microphone positive and microphone negative as they'll both be outputting the same signal but at opposing phases which will be handy for the preamp circuit we'll be building later now as the goal is to isolate the capsule from desk noises a normal audio cable is just not going to cut it for wiring these legs up as even thin varieties are far too stiff and allow vibrations to be transferred straight into the capsule and become very audible a solution to this is to actually make a custom cable using some thin enameled copper wire like that used in the windings of small electric motors with the mass of this wire being so low vibrations just won't be able to travel through it and being enameled it means that short circuits are prevented if they ever touch each other however as they are bare wires they're still vulnerable to electrical interference with the normal audio cable this interference is dealt with by an outer shield of copper strands that wrap around the middle two cores preventing interference from affecting them and a great way of replicating this functionality is to use some two millimeter desoldering wire now you might think that the only use for this stuff is to enable the removal of solder from bad joints but taking a close look at it reveals that it's in fact braided in such a way that allows it to be opened out with something like a knitting stick which returns the braid to its original pre-squashed hollow shape this means that the delicate enameled wires can be pulled back through it resulting in a fully shielded 2 core microphone cable that should block pretty much all vibrations from traveling down its length due to its extremely low mass once the enamel has been sanded from the ends of the thin wires they can be soldered up to the remaining legs on the transistor with the shield itself going to the capsule's ground tab after making sure that they're both connected properly the polarity needs to be marked making it easy to join them up to some normal audio cable with the red wire being for the positive signal and the white wire being for the negative signal and heat shrink protecting all of the joints so with the cable now sorted you might think that it's ready to test out on something but not so fast just like unshielded cables a large diaphragm capsule will pick up a lot of interference from the surrounding environment rendering its output unusable this is why microphones always feature a dense metal mesh around their capsules as it blocks all interference while allowing sound waves to pass right through unobstructed to start off our version of this we're going to begin with some brass wire mesh which is thin enough to be cut through with scissors after drilling a hole of similar size to the microphone capsule in some wood this mesh can be shaped by hammering a suitably sized cylinder or dowel down on top this is an easy way to make some really nice custom shaped grilles that match the capsule and we need one for both the front and back to join these together we'll need a thin brush strip which needs to be made into a ring that the grilles can fit into the reason why we're using brass here is because besides looking really nice it can be soldered too allowing for easy welds in a home environment while it is possible to solder these together using a reasonably powerful soldering iron another alternative is to use a small kitchen blow torch as these are super cheap and work quite well for jobs like this as you'll see in a moment so after polishing it up with some wet and dry sandpaper followed by some metal polish the join is barely noticeable but before the capsule and grills can be mounted to it some hooks are required for the suspension system i found that a good way to make these is to bend some brass wire into small loop shapes and then solder them to the ring directly with some flux and solder although this time using a torch from behind is recommended as it makes no physical contact so minimizes the chances of knocking it out of position after giving this a final polish the capsule and grilles can be pushed inside and held in place with some epoxy though it's worth noting that they all need to make electrical contact so that they work as a grounded shield around the capsule all of this effort is definitely worth it in my book as it looks great with a real retro charm to it but there is one serious flaw in its design it's not immediately obvious but after testing i found that having the brass cylinder extend back as far as it does affects the audio pickup in quite a significant way you see the capsule we're using is designed to be highly directional and only pick up sounds from in front of it the way this works is to actually allow sound waves to enter in at the rear of the capsule through many small holes that are precisely sized and positioned to cause a delay in the sound as it enters here resulting in the cancellation of sounds from off axis because the cylinder interferes with this delay the cancellation effect is reduced and the microphone picks up a lot more off-axis sound which in some cases will be desirable but for vocal use not so much thankfully remedying this is fairly straightforward as drilling plenty of holes along one edge of the initial brass strip as well as making it as shallow as possible allows the sound to enter in at the rear unimpeded so it leaves intact the capsule's directional pickup ability and in my opinion it looks even cooler in appearance thanks to all of these holes so with the capsule encased and wired up like this it's time to make the all-important arm and suspension system for it brass is again ideal here only this time we'll be using it in the form of three millimeter rods which can be bought from places like amazon and ebay links in the description below as the ends of these are a bit rough when cut using a file to round them off is a good idea especially when followed up with a drill and wet and dry sandpaper as a highly polished finish can be achieved their job is to provide support from which to suspend the microphone from and i'm bending mine slightly for aesthetic purposes after which some more brass wire can be used to make the anchor points similarly to what we did on the capsule they do need to be securely held apart though so the remaining rods can be bent into arches and length over to meet in the middle which allows them to be soldered together with a short brass tube more about this in a moment after soldering the side pieces to the ends of these larger arches as well you can see that it makes for a really nice sweeping shape and it's fairly structural as it's essentially two curved triangles before the microphone can be suspended from it though it does need a support arm keeping with the brass theme some brass tubes are needed this time along with a brass rod that can fit snugly inside them this brass rod is fairly critical as shorter lengths of it can be cut off to make some internal end caps that can be soldered in place to one end of each tube this makes the ends solid enough for some through holes particularly as the surrounding area needs to be filed flat this flatness allows the tubes to be clamped together using a screw to make a hinge and as the main structure remains hollow it will allow the microphone's grey wire to be routed through them later to function properly though this support arm needs another hinge at the bottom as well which can simply be made by giving some more brass rod cutoffs the same filing and polishing process that we used earlier and clamping them in place with a few bent pieces of brass the main arm can be slid down on top of these like a sleeve and held in place with some more screws and just like that we have a fully articulating arm and cradle system but before it can be assembled together with the microphone suspended from it we need to work on the third and perhaps most important part of this build the preamp and usb interface you see although the signal from the microphone is strengthened by its transistor it's still not powerful enough to actually send sound to the next stage and need some amplification in a studio environment this amplification is usually provided by a separate unit available in many shapes and sizes for different use cases but usually at a significant price tag as the plan is to keep everything self-contained and low cost for us it means instead building one from scratch in an effort to keep this simple for those of you who want to recreate this project at home i've designed a preamp circuit that uses minimal components so it's fairly straightforward to put together and in the description you'll find a pdf containing all the parts required and a strip board template that you can cut out the idea with this template is to line it up with the holes on the strip board and stick it in place using some double-sided tape poking through all the holes with the pin as marked before adding any of the components though we need to drill through the board at these outermost dots which can be used later along with some pcb pillars for mounting purposes and with that we can begin on the template straight lines represent direct connections that must be bridged of which there are three next up are the resistors although it's worth noting that some of their values have subsequently been updated since filming so be sure to check out the template to be up to date this process basically continues with some connectors an ic holder and a few capacitors all of which are clearly marked on the template the last component to add here is a rather special one in the form of an isolated voltage booster which takes an input voltage of 5 volts and boosts it up to not only 15 volts positive but also 15 volts negative which is important as that's what's required by the component that makes this whole thing work a that 1512 integrated audio amplifier this little beauty is essentially what does all of the amplification taking the tiny signal from the microphone and boosting it up to a line level output all while contributing barely any noise at all to the circuit underneath this ic is the only place where the copper traces need to be severed to complete the circuit now it's worth noting that i'm by no means a circuit designer and this one may have plenty of room for improvement if you have a comment or feedback about how to improve any aspect of it feel free to send me an email and i'll update the template accordingly anyway with this soldered up it needs a housing to keep it safe for aesthetics i've decided to introduce some wood here particularly as this piece has a really nice grain structure being wood though it's not going to provide any interference protection but this can quickly be remedied by adding some brass mesh and grounding it though it's important to add an insulator between it and the preamp to prevent any short circuits so with the preamp complete the last thing to add here is a usb audio interface from my experience even cheap ones like this from amazon can have a super clean input as the circuitry they use has been around for years now so it's fairly mature while it's possible to leave the original usb port in place i would like mine to be usb type-c so i chopped it off and replaced it with a little usb type-c breakout board i have a full video about this topic in the description for those of you who need more information about this process now the preamp itself needs to pull power from this type c connection as well so i soldered up a couple of wires to its 5 volt output for this to be passed on so with that done it can be glued to the rear of the base and the interface mounted wherever there's room for it after which the audio cable can be plugged in as well as the power cable as shown here so the last thing to do is make the rest of the case for which i'll be going back to using brass and bending it to shape adding some screw mounts to the inside in the form of some brass pillars that are soldered in place this shell can be capped off with one final piece of wood again using some brass mesh to add some interference shielding a volume control knob can be added here as well which is just a rotary switch with various resistors the values of which you can find on the project pdf using a rotary switch like this allows for repeatable volume levels though it would have been nice to have a brass control knob but this silver one will do for now so with all these individual components completed it's time to put them all together and see what the final form looks like as well as more importantly test out how it sounds but before we get on with that it's time for a quick add from this video's 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your capital is at risk if all of this sounds a bit of a minefield it's worth noting that free trade have many helpful guides to take you through the basics of investing and a community forum that you can partake in to discuss everything investing related now the best bit is that if you sign up at free trade dot io slash diy perks they'll give you a random free share in a company such as greg's all right move worth between three pounds and 200 pounds once you've funded your account and one of the things i noticed when i signed up is how easy it is to get your money from your bank into the app and start investing straight away and i'm quite looking forward to being able to actually make my savings do something rather than just being in a bank account so if you want to do that too don't forget to sign up at freetrade dot io diy perks and get investing today so the first thing we'll put together is the support system remember that short brass tube that we added here well it was cut from the same tube that the brass rod fits into and so a little insert can be made to match its length and then tapped to add a thread down its center this can then be inserted into the tube and screwed to a little homemade bracket as you can see it needs to be mirrored on the other side as well only this time it gets attached to the arm and is orientated at 90 degrees the short tube in the arm by the way was mounted by using a file to make a matching socket for it and then soldering it in place as you can see gluing some material to the inside edge is necessary as it provides enough friction to add some stiffness so that it doesn't flop around the microphone's output wire can now be threaded through the holes in the arm and routed down to the bottom after which the whole thing can be mounted onto the base after threading the microphone wire into this as well its connector can now be added and then be plugged into the preamp along with the gain control switch and closed up pretty sweet this means that the final thing to do is at last suspend the microphone for which we'll need some nitrile o-rings these are usually used as gaskets but the material itself is really good at absorbing vibrations so it's perfect for using to support the capsule so are you ready [Music] [Music] with the polished brass and sweeping curves it looks better than i ever thought that it could but the real question is does it have the acoustic quality to match well you've been listening to it this entire time so you can be the judge personally from my tests i think it sounds amazing it's got a really clear high end without sounding harsh and plenty of low end presence as well so it sounds really smooth overall and this really does punch well above its weight for what it costs to build which is roughly 30 dollars for example if you are starting out on youtube with some narration or maybe doing a streaming setup you might splurge out on this nt usb microphone now despite costing three times as much as this diy microphone it's actually a fairly significant step down in terms of its audio quality with a higher noise floor and far less clarity i've done a few tests with it actually and you can find those linked below to verify all my findings here now on top of a poorer sound quality by default it's just the microphone that sits on a desk and if you were streaming for example that's just going to pick up a lot of sounds from your keyboard and it needs really an extra boom arm and shock mount which again is an extra cost whereas with the diy microphone it's all built in and already there so that's a pretty impressive result really that it can beat a more expensive usb microphone that you might buy however how does it compare even higher up the quality chain well here i have a cad e100s which cost me about the equivalent of 600. and i use it for my narration normally and it sounds amazing i love it and i haven't felt the need to upgrade just because it sounds so good however it also needs a 200 preamp in order to get a sound to my computer so an 800 dollar setup should sound better than a 30 diy microphone right well no not at all you see the diy microphone actually uses the same capsule that's in this cad e100s and as the preamp just amplifies the signal without adding any distortion or altering the sound in any way it's not really a surprise that it sounds the same even in the noise floor department honestly why buy an 800 setup when you could build it for 30 dollars it really is looking good so far however how is it going to compare with something more expensive how is it going to compare against the king of microphones that's right this is a neumann u87 ai a 3 000 microphone that's 100 times as expensive as this this is going to be interesting testing testing one two three this is with the neumann u87ai and it's one of the gold standard microphones and is used in studios throughout the world due to its natural sound quality and ability to be used with many different things like different instruments and stuff and i'm going to switch over to my diy microphone now so that you can get a general idea of the differences in the way these microphones render sound and yeah you can decide which one you prefer on my voice at the very least i know this isn't a very conclusive test because with a microphone you would want to test it with different voices and different instruments and all sorts of things but this is all i can do for now and it just gives you a general idea now a big thank you must go to antoine for lending me this thing because it is very expensive and it was a fantastic timing i've got to say so what do you think so i hope you guys have enjoyed seeing how to make your very own high quality usb type-c microphone for me it's been quite a long journey to get to this point i've been researching it for a long time on how to actually effectively do it in the most simple manner so i'm glad to have finally gotten this out there and if you do want to make one yourself you can find all the details in the description below but other than that i'm matt you've been watching diy perks and i hope to see you next time goodbye for now

Channel: DIY Perks

Views: 6,376,611

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Id: LoQu3XXIayc

Length: 23min 33sec (1413 seconds)

Published: Wed Nov 03 2021