dual woofers

[uncooked]

hi im thinking about building some monster speakers. with dual woofers, and maybe even dual mids and tweets.

the question i have is how do you join in both woofers or mids etc... is it a special crossover with 2 driver outputs for each. can anyone explain how this would work.

im more of a wood type of person, i can build a good box but the internal wiring up not completely up to par on yet.

im thinking of going with dual 15's becuase i love the bass that 15 inch woofers put out, and whats better then 1? 2!!!!!

 

[mhardy6647]

Basically you can the voicecoils of the two woofers in series or in parallel. I am assuming you intend to use two identical woofers per speaker. If so, wiring them in parallel will halve the net impedance (e.g., two 8 ohm drivers in parallel will present a 4 ohm load). Wiring them in series will double the net impedance (e.g., our same two 8 ohm drivers in series will present a 16 ohm load). Keep the 'net' load in mind when designing a crossover.

The one caveat in connecting drivers in series is that the inductance of the first woofer's VC is now in series with the second woofer. This may have some odd, frequency dependent audible effects.

Note that I have adroitly side-stepped the issue of what effect connecting woofers pairwise has on the resultant Thiele-Small parameters for the pair. I am not qualified to comment on that, but I am sure someone here will!

 

[uncooked]

thank you, that helps alot.

why is it that i have speakers with dual woofers 6.5 inch though and there 8 ohm. just a different crossover style?

and yes i would use the same type of woofers for all 4.

so what would i be talking in ohms, if i was to have dual mids and dual woofers, and a single tweeter? still 4 ohm? or would i drop down to 2 ohm?

 

[gatemplin]

"why is it that i have speakers with dual woofers 6.5 inch though and there 8 ohm. just a different crossover style? "

Those drivers would be 4 or 16 ohm to combine for 8 ohm.

"so what would i be talking in ohms, if i was to have dual mids and dual woofers, and a single tweeter? still 4 ohm? or would i drop down to 2 ohm? "

Since the different drivers do not reproduce the same signals, they are not really in parallel. A 4 ohm tweeter does not combine with a 4 ohm woofer to make a 2 ohm speaker, it is still 4 ohm.

Having dual woofers or closely spaced mid ranges is usually fine. But dual tweeters can have a weird frequency response, and since they are usually much more efficient, you will be wasting money on the second tweeter.

I recommend you take a look at tried and tested speaker kits, you are guaranteed good results. Or if you want to design your own at least read the Loudspeaker Design Cookbook by Vance Dickason and other DIY speaker books. Good luck with the project.

 

[GordonW]

The format I've had the best luck with, with multiple woofers and midranges, is what's known as the WWMTM. From the bottom of the cabinet going up: woofer, woofer, midrange, tweeter, midrange. Basically, it's an MTM D'Appolito array, with two large woofers under it.

With these, I generally run both woofers in parallel or series, on the same crossover, same with the midranges. There's only one tweeter, so you don't run into the problem noted above, with tweeter frequency response wonkiness (comb filtering, etc).

Ha, monster, you say? Will it be able to compete with the "Coffins", I'm building? Dual EIGHTEEN INCH woofers, dual 6.5" pro mids (Eminence) and a horn supertweeter! 10.25 cubic foot box, 102 dB sensitivity...

Here's a picture of the general driver layout described above. This is basically to-scale of what I'm building, just with different ports than are going into the final (they're getting a big 4" x 17" area, 7.25" long rectangular duct instead of the round ports, since it fits better in the box)...

 

[uncooked]

dual 18's jeez. what kind of amp you planning on running them with?


that design looks very nice, its similar to what i had in mind

woofers on the bottom just like that, but then the mids in the middle side by side and a tweeter in the center at the top. but i think the way in that pic might sound better, and actually look better when i think about it.

anyone know of a name of one of thoughs programs that tells you how much cubic feet you need inside the cabinet for what your building? "hopefully free"

thanks you guys, helped em out alot. speaker building looks like it would be alot of fun. Even with all the frustrations that will come along. always fun to work through them and get a good outcome.


I still cant get over the dual 18's!!! are you serious lol. 15" woofers are hard enough to find room for. you should take pics along the way of building thoughs bad boys. I'd love to see em.

so where are they going in the house???

 

[fredt300b]

Monster Speakers

If you want a speaker pair that's visually impressive too there's another option to consider, a line array with separate powered subwoofer. The distribution of the midrange and treble among a relatively large number of midwoofers and tweeters reduced the distortion and permits very high volume levels with good clarity. The use of small (typically 5.25") midwoofers results in fast midbass that you wouldn't get with large woofers. And with a separate powered sub you have good control over the bass loudness in relation to the rest of the audio spectrum. Turn it up a bit and it will shake the chair under you. Here's a picture of one of my Linus 2 arrays, which I'm using with two Titanic 1200 powered subwoofers. The Linus sells for $900 in kit form without the enclosures.

If that's over your budget you can build an array with ten midwoofers and one tweeter for under $300. You can see an example, the AnoreXiarray, at http://fredt300b.smugmug.com/gallery/132721

 

[fredt300b]

Monster Speaker

Sorry, the picture didn't make it into the post, but you can see the Linus and the AnoreXiarray at the link I included.

 

[uncooked]

thoughs are my future goal, but i want to start out with something smaller like a basic 2 way or 3 way system, im thinking i may only build a cheapy soon to practise on. like some rat shack 15" woofers and a pair of decent but not overly priced tweeters and see what i can put together.

if im still enjoying it after thoughs then i ll continue building making each one a bit harder. with a few more drivers.


what do you guys think of the MAT electronic tweeters and mids. for a first time build type of thing?

 

[gatemplin]

For a first time building project, I recommend you check out www.creativesound.ca . They are also out in BC and they have many reasonably priced starter kits. You will gain valuble experience and the results will be great.

 

[DanTana]

First thing you need to do before building any speaker, is ask yourself, "What do I want?" and you go from there. Actually, bass is the easiest thing to do, all you need are a few big speakers and boxes and of course enough power to drive them. Low frequencies are the least critical part of a system. Not that it isn't important, but is easiest to obtain without much effort. Now for a finely detailed system that will allow you to hear every single nuance and note with utter perfection is what is hard to do. Most systems are a compromise at best, and some pull it off pretty well, usually those are the ones sitting in the high end audio store behind the sound proof chamber. If you want bass, you can always add a subwoofer later, either with a built box or just a simple kit. The market is full of subwoofers that do a reasonably good job for about $250.00, the Athena comes to mind. My personal choice is to make the midrange and upper frequencies the priority, those are the most critical listening areas and most temperamental.