Selecting Drivers and Why it Matters!

[Music] everybody welcome back to another Tuesdays Tech Talk before I really get started today with today's episode I want to throw a big congratulations out there to rob Renee at new record day he's the guy who edits all these videos and puts them on his channel he is wife Sarah just added two new additions to their family this week Sarah had twins this week so their lives of course will never be the same but I'm sure it'll be filled with lots of joy congratulations Ron and Sarah and now this week's episode this week's episode got me thinking because I've had quite a few calls recently of course let luck do with the the Tuesday Tech Talk videos about designing crossovers for people in designing crossovers for individuals and if it's an upstart companies contact me want me to help them with the crossover development and of course I love doing that work for me that's the most fun of all the stuff I do love doing crossover design work I love the engineering the ass by all aspects of it or to me are a lot of fun I could just light speakers up here and do crossovers every day that would be great that's a more fun than operating a business that's for sure but I've had a lot of guys asking me recently to design crossovers for stuff that they can't send to me let me reiterate guys that in order for me to design a crossover have to have the actual speaker here I'm actually taking measured responses of that speaker to see what the output is in that box if you change the the width of the baffle the height of the baffle you're changing the baffle step loss here you're changing the spacing between the drivers all kinds of things all that has to be taken into account to design a crossover so I have to have it here the thing is I've had a couple of guys asking me to design crossovers and they're saying I have I picked out this driver I picked out that driver but then maybe they haven't purchased drivers yet they're just saying this driver in this driver can you design a crossover for this well yeah same thing still applies have to have it here but in some cases I'm looking at driver selection and I'm seeing a metal cone driver that has a huge resonant bump in the impedance curve and a lot of break up and right in that range and that's something that as a as a designer I look at it an essay I'm gonna have to filter that out of it so I'm gonna have to keep it below that range so that that ringing is not in the playback so that means that particular one from a aval range limited to about 1,500 Hertz the tweeter they picked out which are they're looking at it was an AMT tweeter that would only play down to about 3000 Hertz so that they wouldn't even reach each other you know for me to design crossover for this stuff the drivers have to be compatible these are if you bring us in on the earlier design aspects then bringing us in on the tail end and trying to fix something so today I thought with all this indecision about what drivers to use and things like that I would kind of go back to the beginning of gr research and talk about what we did when we were designing drivers and how we selected the drivers that we used and kind of that whole process versus some of these companies that say up pick this woofer and pick this tweeter and we'd say oh I see why well they they looked good well they look good visually but if you look at the parameters they're they're not suitable for what you're doing now one of the speakers that I tested last week the the woofer which was fairly expensive was in a box volume that was twice the size that needed the drivers were spaced too far there's too much surface area around the drivers you know guys it if you're early in the stages bring us in early and let us help you with the design elements and avoid some of the problems and we'll get you further along so when my partner and I got started in this the first thing we did was we started ordering drivers from everybody we ordered drivers from Dynaudio from peerless from Viva to scan speak the sales drivers kvass folk cow you name it we ordered tons and tons of stuff and just started matching things that we thought would work well together and listen to different things and some of the things we noticed was that the more expensive drivers didn't necessarily sound better and different materials really made a difference in how things sounded one of the things that stood out when we first started was we got a sample sent to us from peerless of India who was at that time making drivers from peerless to Denmark and they had kind of recently broke off on their own and they still carried the name peerless they sent us a sample that was similar to our m130 with driver here a little polymer chassis paper cone in the type of quantities we were considering they weren't really expensive but when we we started playing with these things and listened to them they sounded fantastic better than most of the expensive drivers that then we were using and thought well what's the difference here why is it so much better sounding than some of these more expensive drivers is it the polymer frames is it something they've done in the motor structure is that the materials being used so we sent them different cones and we had we had versions of it made out of the honeycomb Kevlar or woven Kevlar there was some money I think a poly cone was used there was some carbon fiber in here I've laid out different cones frida locators carbon-fibre come this is another carbon fiber of these two or some type of polypropylene this one's a paper cone it's a little heavy paper cone but a paper come bulletproof material of course you see that in the marketing of some of these companies they all sounded different all the different materials all had a different sound to them and we compared the same driver but with different cone materials and then we wound up comparing the same driver with the cone material that we like best which sounded the best which was paper Center by far the best and it was the smoothest and then we tried different dust cap social round dust cap this shaped dust cap there was a kind of an inverted dust cap and we listened to those who measured only compare them and we did a lot of research and development really put a lot of time into that and that's what actually led to the m130 which we sold thousands of these things and we did an 8 on version 16 own version this has been a really successful driver this really helped kickstart our whole business early on and we used some folk cow products we became a distributor for folk cow drivers kvass and all kinds of different parts and components we stock tons of that stuff and we did our due diligence we listened we compared and one of the things that really worked really well was the McComb material in the shape of cone made a nice smooth roll-off I mean you can see the response most smoothly off at the top we weren't having to add tons of parts to correct anything the impedance curve was smooth and winter residence no ringing is a non-residents frame all those things really add up a lot of little things add up to big things things do not look for compared to this driver this was something we used early on and big light source we did this is like a little mini subwoofer as you see us it's got a huge motor structure on the back of it compared to the little m130 but this is light weight moving mess this is a heavy moving mass so heavier moving mass you need more motor to drag that thing around but more motor doesn't necessarily mean mo bettah just because it's got a bigger magnet on the back of it doesn't mean it's a better driver I know if you've come from the car audio world where bigger is better you may have been brainwashed into thinking that a little bit and on some of that stuff in car audio what they'll do is they'll just hang a bigger and bigger magnet on them on the back of their woofer to create a field strength that's way too strong and so to compensate they'll just make the gap bigger around the voice goal so the reducing filled strength by increasing the field strength there at the gap we'll just make it get bigger and so they're compensating for the larger motor structure and what they could do is just put a smaller motor structure on the back of it and put a normal gap around the voice cool and have the exact same fill strength on the coil but that doesn't sell what sells is a great big honking magnet on the back to speaker so you see that a lot in car audio not quite so much in a high-end home audio and high-end drivers but you still see it this driver here is a metal cone driver this is a pretty good driver for a metal cone driver it doesn't have a really harsh metallic sound a really artificial sound like a lot of the metal cone drivers do in the motor structure of course looks huge but a lot of that is because it is shielded when you when you shield it you'll add a bucking magnet which is a second magnet it's this flipped around so that when you cram it onto the back of the other magnet you're canceling the stray fields and they put a shielding cup on the back of it so it looks huge but part of it is just huge because it's shielded here's another sample that I had sitting back here I thought I'd pull up this is a wave core driver weight of core drivers were pretty nice drivers I haven't really found any that had parameters that were in useful ranges that have really motivated me don't want to do something with but they make nice drivers paper cones nice Roelofs nice frames you know still it's a metal frame it's gonna have a little ring to it but pretty nice drivers the and they're not crazy expensive you know there's good drivers out there that you can find without spending tons and tons of money higher dollar amounts doesn't necessarily mean greater performance so you have to separate price out of the equation don't look at something-something thinking because it's so expensive that it's got to be better if that is not a measuring stick now when you're looking at drivers you know they're they're expensive for a reason a lot of it is the small quantities that they're being produced in and the amount of markup that they could put on it and if they're selling to a distributor and that distributor is marking it up and so on there are things though that make drivers a little more expensive compared to a little m130 the NQ driver is a dual motor design it's got a neodymium magnet on the pole piece it's got a ceramic magnet on the top plate big 44 millimeter voiced cool copper shorting rings above and below the gap but this isn't all out after polymer chassis nonresident and a paper cone smooth response we sell these for $109 a piece they'll easily easily compete with me compared against any of those 200 and $400 drivers they're just not that expensive because of the amount of quantity that we have made it once we have it brought over from India it's inexpensive to have stuff shipped from India their duty free zone then in the shipping in the container is inexpensive and we have it sent to port of entry in dallas-fort worth which pays for the inbound shipping you know across the layout to the port so we save a lot of money and the way we're ordering it the quality control that those guys has been fantastic we've had great luck with them so any of our drivers that you want to consider a lot of time and engineering has gone into we've done everything we can to make them to where their user-friendly if you want to order one and use it in some other design fantastic if you want to sort a completed kit that we've done all the homework in you know for you for and we just hand you everything and all you have to just put together you're way ahead you're way ahead versus designing something on your own I understand a lot of you guys the fun for you is is that something on your own so what do you really look for there's a couple of things when you're you're looking at your woofers or your small drivers that you want to look for one of course look for a smooth frequency response look for a smooth the frequency response that is above the range that you're going to use in it if you've got a metal cone driver of some kind and you think well it's good within that range but at the top there's all this breakup and ringing keep in mind you're gonna have to put a lot across our report parts on that to get that out of it you're gonna have to pull that down an output are you gonna hear all that ringing you can't just put a second order even third order sometimes filter on it because the ringing is still gonna be there so look at the frequency response the other thing look at the impedance curves on drivers when you see an impedance curve and you look at the bottom of its range you'll see a rise at its FS right at the middle that's it's for your residents and to come back down watch that range as it settles and starts it starts to rise if you see little bumps in the in the impedance curve and in some cases you can see a lot of bumps I had a company our good guy in Las Vegas send us some of the really expensive full range drivers or eight inch drivers papaya based cone material huge neodymium motor structure on it super high sensitivity really expensive if you look at the impedance curve there are jaggedy bumps all across it that are indicative of internal resonances so when I measure the frequency response you can see peaks and dips all of the responses it was really rough then you looked the spectral decay QC stored energy and every one of those Peaks all those residences stored energy stored energy lot serene guys when you see that no matter how expensive the driver is that's a red flag all that stuff's a red flag look at that impedance curve any little residents peak you see they're like even if it's a small peak then look up into the frequency response and you may see a corresponding dip or a little peak there and if possible if they have spectral decays would easily they'll provide spectral Takase you can see exactly what's going on the spectral decay when you see that you know that you're gonna have to cross that over a full octave or more below that range to get that out of it or you're gonna hear that ringing in that resonant it's gonna be there in the response so when you're looking at drivers look for those things look at the impedance curve look at the frequency response think about how many parts you're gonna have to put on there to correct it and if it's smooth enough to stay within the band that you're trying to try to use it in you're trying to reach a tweeter with one of these smaller drivers that you're looking at will it play up into that range without problems and cross into that tweeter same thing with the tweeter is its frequency range low enough that it'll reach the driver that you're trying to cross it to in general stiff cones metal comes more problematic in those in those ranges they're gonna have more ringing more breakup you're gonna have to add more parts on there to correct them if you were starting out and you're doing this and you've never really done loudspeaker design before you a rookie at it look at paper cone based drivers they're gonna be free of a lot of those problems they're gonna be a lot easier for you to design crossovers and filters for and again if you're if you're going at this you know first timer and you're trying to figure out how I'm gonna design a crossover for this might say right now if you don't have the tools to do it with it's gonna be tough you need to have a measurement system where you can do a gated time window that means you're doing a you're looking at a little sliver in time the frequency response of that driver without room reflections in other words you got the microphone setup front of it you get the speaker set up you send it the pulse and you say okay I want to I want it to start right where the pulse reaches the speaker right with that impulse response is there and then for four milliseconds I want to look at the frequency response and then I want to put a stop and waiting gate out all the four reflections and ceiling reflect everything in the room that's going on you want to get that out so you can just see the frequency response of that driver if you're taking a room measurement and you're getting all the room reflections in their menu for you you can't see what's going on with those drivers you have got to do some type of gated time window and then you need the parts like we keep stocked here to drop on there and see what it's doing take another measurement check your linear impedance curve see if that's not becoming a problem look at this spectral decay it's a back and forth if you have to have the right tools to do it if you're still thinking you're gonna just tell some company the driver specs and they're just gonna spit out a cross over for you use it some type of software they're gonna be lucky if you get to the ballpark that's why companies and individuals send their stuff to us because we actually do a measured response curve we actually design it based on the acoustic output of the drivers that's the only way to do it and get the highest level of performance why spend four or five hundred dollars 800 thousands of dollars on drivers if you're not gonna design the crossover properly I mean you're just not gonna get there if you're not going to do it right the whole part of the speaker and how it sounds is all based on the crossover design that's as important as anything is all the drivers the crossover is the heart of it that's what's controlling drivers that's what's separating everything that's what's creating that linear frequency response that you want you don't want to frequency response it's rough peaked it's high and one end and low on the other and it's got stored energy that's not what you're looking for so do your due diligence if you have questions feel me the look at stuff I do that I do that all the time I get 30 40 emails a day sometimes people asking us to look at that stuff before I'll look at it for you don't send me a book and tell me your whole history of what you've done and why you've got to where you are just send me your question have me look at something I'll look at it I'll help you in any way that I can't I may ask you to send it to me at some point when you get ready to design a cross over I can help easily that way we do offer free measuring and testing services I want to reiterate that you send it to me I'll measure test it for you and we'll give you advice that's just part of what we do and I enjoy doing it so that's it for today I hope this was helpful I hope it helps get you guys kind of pointed in a good direction and again throw your comments down below and thanks for watching see you guys next time

Channel: New Record Day

Views: 26,814

Rating: 4.9191918 out of 5

Keywords: Tuesday Tech Talk, audiophile, hifi, loudspeaker, fullrange driver, comb filtering, GR-Research, Danny Richie, crossover design, measurements, best loudspeakers, tube amplifier, preamplifier, diy speakers, audiophile speakers, audiophile music, amplifier, best voice, audiophiles, high end, baffle step loss, open baffle, fast bass, subwoofers, line source, drivers, high power handling, low distortion, the room, speaker upgrade, audiophile loudspeakers, crossovers, DIY Audio

Id: 60oKDQ7YgoY

Length: 20min 59sec (1259 seconds)

Published: Fri Nov 15 2019