Neo__04 Posted February 29, 2016 Posted February 29, 2016 Hey all, Contemplating doing a diy speaker design and am tossing up between kits and drivers etc. The kits id like to build get quite expensive when you add freight from the states and id like to possibly use some drivers i already have. Im wondering if someone with crossover design experience can tell me, If i have the speakers, a minidsp and umik-1 measurement mic, am i able to experiment with that gear to work out how i want my crossovers, and then learn how to translate that to actual physical crossovers? Im wanting to use SB accoustic, SB29RDNC-C000-4 - TweeterSB17NRXC35-4 - Woofer I've had these drivers previously in a 2 way active car audio setup. Running the minidsp for crossovers. Worked great. Id like to reuse them in some bookshelf speakers, but learning the physical crossovers is my dilemma. Any advice would be great.
almikel Posted February 29, 2016 Posted February 29, 2016 yes you could... but if I understand you correctly you want to use the MiniDSP to help design a physical passive Xover? Why wouldn't you just run the MiniDSP as an active Xover permanently? cheers Mike
Zaphod Beeblebrox Posted February 29, 2016 Posted February 29, 2016 Designing a crossover requires the following: * Suitable test equipment (you need to run impedance curves and frequency response/SPL measurements) on all drivers). * The ability to use the above-mentioned test equipment. * Knowledge of electronic principles and how to apply those principles to practical purposes. IOW: Designing a crossover requires much in the way of equipment and experience.
davewantsmoore Posted February 29, 2016 Posted February 29, 2016 Any advice would be great. No easy answers if you really want to DI (all) Y. Start reading books, articles, and well documented DIY designs, which teach you how to measure speakers, and how to make good choices (drivers, layout, crossovers) for a speaker design. They way I learned, was to follow existing DIY designs, and then to question why they made certain choices, and if there were alternate, or better, choices to make in the design. I've had these drivers previously in a 2 way active car audio setup. Running the minidsp for crossovers. Worked great. Id like to reuse them in some bookshelf speakers, but learning the physical crossovers is my dilemma. Then just do similar to what you did in the car (however you decided on the minidsp settings) for the bookshelf speakers. If you have the urge to go further ..... then the path to learning how to design a good speaker is questioning everything, and learning how to make an investigation when required. Once you've put the drivers in the box, and set something in the minidsp, and got a result ..... I can guarantee to you, that no matter what you think of it - it will be absolute rubbish. Learning about speaker design will involve you asking yourself "what is wrong with it?", realising that the answer is "I don't know" .... and then learning how to investigate your speaker design, discovering what is "wrong" with it, and then working out what to do about it.
Neo__04 Posted February 29, 2016 Author Posted February 29, 2016 Well, sounds like its not going to be an easy job. I didnt want to run the minidsp permanently as i wanted to learn about making passive crossovers. So where does a newbie begin? Im sure I can start with a predesigned kit, premade crossovers etc. But what does that teach me? All im going to be doing is constructing the cabinet to spec and then the speakers are made. I think i'd like to get into the hobby and make more sets in the future, but i think i'd like to learn more about the driers, crossovers etc to be able to learn how to chose drivers for a certain project, then how to design crossovers, then to design the cabinet. I can imagine there is a lot involved, but im good with electronics, keen to learn but just dont know where to start.
Zaphod Beeblebrox Posted February 29, 2016 Posted February 29, 2016 This is an excellent resource: http://www.parts-express.com/loudspeaker-design-cookbook-7th-edition-book--500-035 3
Cloth Ears Posted February 29, 2016 Posted February 29, 2016 Well, sounds like its not going to be an easy job. I didnt want to run the minidsp permanently as i wanted to learn about making passive crossovers. So where does a newbie begin? Im sure I can start with a predesigned kit, premade crossovers etc. But what does that teach me? All im going to be doing is constructing the cabinet to spec and then the speakers are made. I think i'd like to get into the hobby and make more sets in the future, but i think i'd like to learn more about the driers, crossovers etc to be able to learn how to chose drivers for a certain project, then how to design crossovers, then to design the cabinet. I can imagine there is a lot involved, but im good with electronics, keen to learn but just dont know where to start. I would suggest having a look at Vance Dickason's "Loudspeaker Recipes" book. In that he designs 4 2-way items from scratch, on with an extra pair of active woofers. It's about 15 years old, so some of the software he uses is probably superseded by now, but the effort being put in to the design and the paths he takes are still valid. He also mentions that the crossover is by far the most difficult thing to do well. If that doesn't scare you off, then it will probably give you a useful start in how to go about the process. 3
davewantsmoore Posted February 29, 2016 Posted February 29, 2016 Nothing like this is usually easy Im sure I can start with a predesigned kit, premade crossovers etc. But what does that teach me? Depends how you approach it. If you choose 'pre-made crossover kit X' and it comes with some resistors, capacitors, and inductors .... then aside from just assembling it, and attaching it to your drivers..... to progress further, with an ability to 'DIY' you need to: Understand WHY they used the components they did, to create the filters Assemble the filter, connect your drivers, and then learn how to quantify the result (ie. measure the outcome) Examine the result, and learn how to assess, "is the result good" Learn about ways the result can be improved
andyr Posted February 29, 2016 Posted February 29, 2016 Well, sounds like its not going to be an easy job. I didnt want to run the minidsp permanently as i wanted to learn about making passive crossovers. So where does a newbie begin? Im sure I can start with a predesigned kit, premade crossovers etc. But what does that teach me? All im going to be doing is constructing the cabinet to spec and then the speakers are made. I think i'd like to get into the hobby and make more sets in the future, but i think i'd like to learn more about the driers, crossovers etc to be able to learn how to chose drivers for a certain project, then how to design crossovers, then to design the cabinet. I can imagine there is a lot involved, but im good with electronics, keen to learn but just dont know where to start. Well, sounds like its not going to be an easy job. I didnt want to run the minidsp permanently as i wanted to learn about making passive crossovers. So where does a newbie begin? Im sure I can start with a predesigned kit, premade crossovers etc. But what does that teach me? All im going to be doing is constructing the cabinet to spec and then the speakers are made. I think i'd like to get into the hobby and make more sets in the future, but i think i'd like to learn more about the driers, crossovers etc to be able to learn how to chose drivers for a certain project, then how to design crossovers, then to design the cabinet. I can imagine there is a lot involved, but im good with electronics, keen to learn but just dont know where to start. I had your problem about 15 years ago. Luckily, at that stage our TAFE system existed - so I was able to find a night course at Box Hill TAFE which taught me what you want to know. Now, though ... I don't know where you might go for such knowledge. CAE, perhaps? Andy
Sir Rab of Everest Posted February 29, 2016 Posted February 29, 2016 ... or you hire Paul Spencer to do it for you... 1
Sub Sonic Posted February 29, 2016 Posted February 29, 2016 You do have a couple of things going for you: the ability to take measurements and an understanding in electronics - impedance, resistors, capacitors, and (I expect) inductors. I'd look up the resources the others have mentioned and start experimenting. As you play with the passive components and get mixed results, you will try to find out why you get those results, and will gradually learn. It is a long but fun road: none of us knows everything; we are all still learning too. Regards, SS
Neo__04 Posted February 29, 2016 Author Posted February 29, 2016 Thanks for all the info guys. Yeah I'll definitely chase up the loudspeaker design cookbook, a lot of places reference back to that book so i'll chase one and give it a read. I'll do a bit more homework and might start with a cheap speaker kit, build it, experiment, then build a nicer set
Sub Sonic Posted March 1, 2016 Posted March 1, 2016 Thanks for all the info guys. Yeah I'll definitely chase up the loudspeaker design cookbook, a lot of places reference back to that book so i'll chase one and give it a read. I'll do a bit more homework and might start with a cheap speaker kit, build it, experiment, then build a nicer set Or you could just buy a nice kit, experiment with your own crossover, and then have the original to put in it later 1
Sub Sonic Posted March 1, 2016 Posted March 1, 2016 @@Neo__04 BTW feel free to post any pics or questions about your project, plenty of people here will be interested in it and willing to give good advice :-) SS 1
Neo__04 Posted March 1, 2016 Author Posted March 1, 2016 Thanks again for all the info. Yep i'm gonna order a nice bookshelf speaker kit, just trying to work out which one. I've picked a few, but freight is crazy expensive from the states and I cant seem to source some of the drivers in australia... I cant win lol. Was tossing up between: http://www.diysoundgroup.com/speaker-kits/tango/tango-kit.html - https://www.madisoundspeakerstore.com/mtm-speaker-kits/zaph|audio-za5.3-mtm-pair/ (MTM) http://www.parts-express.com/aviatrix-sealed-mtm-components-only-speaker-kit-pair--300-704 (MTM) http://www.parts-express.com/tritrix-mtm-tl-components-only-speaker-kit-pair--300-700 - (But as an MTM, not tower) Some are getting up to the high $200 usd range, so including freight, its gonna get expensive.
catman Posted March 1, 2016 Posted March 1, 2016 G'day all, Rod Elliott's ESP website has some excellent articles on various aspects of crossover design (both active and passive). Regards, Felix.
Neo__04 Posted March 1, 2016 Author Posted March 1, 2016 Thanks felix, I'll check that out too. Another speaker kit im looking at, http://meniscusaudio.com/swope-each-p-1305.html - (MTM) Also considering these as there is a tweeter upgrade to an SB accoustic SB29rdc which i already have a couple of, so that would cut the cost down a bit .
henry218 Posted March 1, 2016 Posted March 1, 2016 @Neo__4 your drivers are very good. You just have to build a suitable box and take some measurements (freq and impedance) then you can either use calculations or simulation program to create the filters. If u have a commercial speakers (pref similar size) that you can use as a reference, then you can always compared them side by side and decide what to do with it.
Neo__04 Posted March 1, 2016 Author Posted March 1, 2016 Hi Henry, Your comments are what got me thinking about all this in the first place. The speakers i have are definately nice speakers, i've heard they running and they sounded great. So in basic terms....to get started with the drivers i have, Do i model a box in Winisd, Bassbox pro etc, To get the ideal enclosure volume, be it ported or sealed, port length etc etc. Then actually build the box, install the drivers and begin playing with crossovers from there? When i was using the speakers in my car, i was doing measurement in rew (http://www.roomeqwizard.com/) not really using it for room eq, but mainly for working out my crossovers. Similar procedure here? Id much rather use the drivers i have than buy new ones if i dont have to. Thanks heaps for the info, its much appreciated.
henry218 Posted March 1, 2016 Posted March 1, 2016 Yes, start from the box design for bass tuning. REW is one of measurement program that can accept generic mic for freq resp and even impedance measurements, but u need to make the cables for it (i've seen somewhere about this but never try it myself)
Neo__04 Posted March 1, 2016 Author Posted March 1, 2016 Thanks again henry, So i had a play with the Unibox spreadsheet. First time using it, i found a tutorial which showed how to input spes etc, said to design the speaker for 1/2 max rms. So the graphs are based on that. Im a little bit unsure how to optomize box size. The port seems to get quite long, depending on the box size. so i seem to have to go a little bigger with the box to get the port length time. Does it look any good? Also had a play in winisd and attached a diagram of that too. Any feedback on those would also be much appreciated! Thanks again
Sub Sonic Posted March 2, 2016 Posted March 2, 2016 The port seems to get quite long, depending on the box size. so i seem to have to go a little bigger with the box to get the port length time. You can use an elbow on the pipe so that the port has a right angle in it inside the box, just keep the inside port opening well clear of any internal panel. You'll also need to make sure that the dimensions you enter for the port diameter is the same internal diameter of a commercially available port or piece of pipe. Probably stating the obvious, but hey! The box volume looks about right for a vented enclosure, you can play with port lengths later. If you did manage to get some way to measure the speaker impedance, it will be easy to measure the exact tuning frequency of the driver/enclosure.
Neo__04 Posted March 3, 2016 Author Posted March 3, 2016 Thanks for the info, handy to know about the port, didnt know how i would do it otherwise. I'll have to work out now how to take speaker impedance measurements. Any way to do it without specific gear? I read somewhere you can do it with a multimeter, resistor in line to the speaker and an amp playing pink noise or specific frequencies. Or something of the kind.. That might be the last step of the process before i get started with some box building!
Zaphod Beeblebrox Posted March 3, 2016 Posted March 3, 2016 Thanks for the info, handy to know about the port, didnt know how i would do it otherwise. I'll have to work out now how to take speaker impedance measurements. Any way to do it without specific gear? I read somewhere you can do it with a multimeter, resistor in line to the speaker and an amp playing pink noise or specific frequencies. Or something of the kind.. That might be the last step of the process before i get started with some box building! This is your best bet for not much money: http://www.daytonaudio.com/index.php/dats-dayton-audio-test-system.html Anything less than that will waste enormous amounts of your time and will drive you crazy. 1
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