betocool Posted March 19, 2014 Posted March 19, 2014 Hi guys,with a bit of luck and time, this year I'll be able to start a new pair DIY speakers. Not that my current DIY's sound bad or anything, but after two years pause, I'm feeling it's time to start a new project. It's this itchy fingers thing, see?First to the ideas. The image below are the speakers which I own at the moment and am very happy with (waveguides). Now come the ideas. The first one you'll see, should be in the same line as the above, with good quality components (I'm thinking around 600$ per speaker, we'll see), but a 3-way design. Plus, this time, I'm not so sure about the waveguide, but either a vented box or one with a passive membrane on the side. Please excuse the roughness of the sketch, it's certainly a quick sketch and not up to scale (this apology goes for all further images). In my head the speakers are a bit taller and narrower.At this point, I'd be happy if someone jumps in and explains the difference between a vented enclosure and an enclosure with a passive membrane, and what I should take care of.The second idea I have, and it came really just out of nowhere, is a standmount using 4 full-range, 4" speakers. The speakers would be connected in a series-parallel configuration (each 2 in series, each group of 2 in parallel), so the impedance is the same as if only one speaker was connected, but you can use a higher power amp. What concerns me with this design, is the possible cancellation of certain frequencies at close range, not so much at a distance.Again here the question, waveguide, vented enclosure or passive membrane? I have to admit, I'm really tempted to try this ones out, I'm just a bit afraid that the experience/sound might not be 100% satisfying (only a gut feeling).Finally, I sketched (roughly) the 4 enclosures that are known to me. If anyone cares to explain the difference, pros and cons, or provide a link to explain how they affect the response of a speaker, I'd be very grateful. At this point, this is all in the beginning stage, I haven't chosen any components, but I thought I'd share my ideas with you and usually good advice comes out.Thanks for reading!Cheers,Beto
davewantsmoore Posted March 21, 2014 Posted March 21, 2014 (edited) It's this itchy fingers thing, see? We are speaking the same language At this point, I'd be happy if someone jumps in and explains the difference between a vented enclosure and an enclosure with a passive membrane, and what I should take care of. At the risk of disappointing you.... it might be best if you go away and read about the basics, and then use more specific questions or discussion to clear anything up. That's not me being lazy, but it's better for you. Getting it explained in 5 different ... but all [eeek hopefully] correct ways, will make it stick better for you, than one potentially misleading explanation. Essentially, a passive radiator system behaves like a vented system with some practical differences. Start here perhaps: http://www.aespeakers.com/PRFAQ.php Neither are trivial to design well. Don't let that scare you, but also be careful very small changes can make a lot of difference. If you can't measure (like acoustic measurements) what you build, then it will be a stab in the dark. (Learn to measure your speaker if you don't already, it will help you very much) The second idea I have, and it came really just out of nowhere, is a standmount using 4 full-range, 4" speakers. The speakers would be connected in a series-parallel configuration (each 2 in series, each group of 2 in parallel), so the impedance is the same as if only one speaker was connected, but you can use a higher power amp. What concerns me with this design, is the possible cancellation of certain frequencies at close range, not so much at a distance. Yep, bad idea for the reasons you note. You'll have interference above a certain frequency. Much more so in the vertical axis, but also in the horizontal. This approach, but with a single FR driver, and woofer mounted on the side, has been termed the FAST approach by some people.... and it is definitely worth looking at (and is reasonably simple too :thumbs:) waveguides Your speaker doesn't appear to use a 'waveguide'... what have I missed?! If you mean you are considering using one in future ... then working to an already sorted recipe is my best advice. Zaph, JoeR, TG, and others have shown how it can be done with dome tweeters. I have also had success with this approach --- although I have not begun to publish documentation on my efforts, as I am neither ready for "questioning" from those smarter than me, nor ready to present in a style which will impress or educate those with less knowledge. Soon. Hopefully this decade .... and there is obviously compression drivers (designed specifically for horn/waveguide). I sketched (roughly) the 4 enclosures that are known to me. Ohhh. :lightbulb: ..... You mean "transmission-line" (rather than waveguide) !?! Yes? I must honestly say.... If you are asking this question, then the best enclosure for you is sealed. The catch here is that you will usually need to use active filters (ie. ones that can boost the signal) to build the speaker. Sorry if I have misunderstood.... Just yell at me, and we'll go around again. It was 8 degrees (apparent temp) here yesterday afternoon.... so speaker season might have come to an end, and I could be living vicariously through you. I need a heated workshop Edited March 21, 2014 by davewantsmoore 1
masliko Posted March 22, 2014 Posted March 22, 2014 (edited) check this out,you might like these. There a passive radiators on the sub on the bottom.The two towers are stuck together with neo magnets. This guy goes through the whole build on YT,although he's a car audio expert,this system was for his shop! Edited March 22, 2014 by masliko
thoglette Posted March 23, 2014 Posted March 23, 2014 At the risk of disappointing you.... it might be best if you go away and read about the basics, and then use more specific questions or discussion to clear anything up. That's not me being lazy, but it's better for you. At the risk of agreeing with Dave :-) +1. Designing multi driver speakers (well) is not trivial. Even single drivers have a host of challenges Go and do LOTS of reading - especially by designers of or technical how-they-work of well regarded speakers (Osher's Black Dahlia, Olson's Ariel, Linkwitz's Orien and Pluto, the various metronomes; fonkens; NHT 3.3, B&W Nautilus, Quad ESL, LeClerc horns, Duntech ) Then work out what you're trying to achieve - that will determine what compromises you wish to accept and which you wish to avoid. Oh - It's not the be-all and end-all but if you read only one book make it the Loudspeaker Design Cookbook by Vance Dickason. It ignores a whole bunch of stuff (time alignment, refraction, box modes etc) and oversimplifies plenty of other stuff (eg. cross overs) but it's a good place to start.
davewantsmoore Posted March 23, 2014 Posted March 23, 2014 At the risk :lol: There are also quite a few well documented "recipes" out there, which can be built without a lot of understanding of the 'why'.
betocool Posted March 23, 2014 Author Posted March 23, 2014 Alright, thanks for all your answers! Yeah, I meant transmission-line (where did I get the waveguide from?). What am I trying to achieve? Good sound, I guess, an improvement on what I have now... it's hard to quantify since I'm already happy. In a nutshell, a 3-way speaker pair which does not sound worse that what I have now. Like I said, the 4x fullrange design is just a curiosity thing, might leave it for the future. I know I have LOTS to learn about speaker design, I'll take a look at @@davewantsmoore link and try to find @@thoglette book. My problem is I'm quite good with electronics, but mechanics is a mystery. I'll also have a look at the video, when I have a quiet moment. Anyway, I still have this year to do all the work, and I'll keep you updated on the ideas. I know I'll definitively go with a classic square design, standmounts, that's what appeals to me the most.
thoglette Posted March 23, 2014 Posted March 23, 2014 My problem is I'm quite good with electronics, but mechanics is a mystery. If you can get your head around tuned circuits and antennae VSWR calculation then 99% of speaker theory is completely analogous.
henry218 Posted March 23, 2014 Posted March 23, 2014 hi betocool, is that wavecor tweeters? having a 3way is a substantial improvement on the midrange with the bonus of having greater bass
davewantsmoore Posted March 24, 2014 Posted March 24, 2014 Perhaps one of Zaphs projects are the level of documentation (not too much, but not too little) you need?! http://www.stereo.net.au/forums/index.php?/topic/62086-zaph-sr71-my-first-decent-speakers/
betocool Posted March 24, 2014 Author Posted March 24, 2014 Hi Henry, they are Audaphon TWS 30/4 tweeters. I re-posted the building process of my current speakers here: http://betocools.blogspot.com.au/2012/08/speakers-afc-mk-i.html After I changed from my server to Blogger, I lost all my images at some point. Dave, thanks man, I'll have a detailed look tonight.
betocool Posted April 15, 2014 Author Posted April 15, 2014 Nothing new to report really, got Vance Dickason's book from the library about two weeks ago and returned it... I felt as if someone was trying to teach me to read before I knew the letters! I'm gonna check David B. Weens' books, also get them from the library and see if I can shed a better light on my basics. Still going slow though, at the moment I have other activities and thougths running through my head. Cheers! Beto
davewantsmoore Posted April 16, 2014 Posted April 16, 2014 Perhaps try to build a few well documented DIY speaker project and attempt to understand what is going on with those projects before attempting to design anything from scratch. Doing a complete design takes quite some experience and mistakes made early in a design are compounded later.
betocool Posted April 16, 2014 Author Posted April 16, 2014 Probably you're right, I'll also look into some 3-way designs before I start. Maybe this time I'll get a ready diy kit. Still, I'd like to grasp the basics of what I'm about to do, and then move to something more complex.
davewantsmoore Posted April 16, 2014 Posted April 16, 2014 Probably you're right, I'll also look into some 3-way designs before I start. Maybe this time I'll get a ready diy kit. Still, I'd like to grasp the basics of what I'm about to do, and then move to something more complex. If you have a recipe to follow you have something to measure how well you did against (does the speaker you created measure the same as the original?) Many DIY projects provide a lot of information on why they did what they did, that you can learn from.
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