PE's "magna cum laude" project is fairly popular, and for good reason. Those things can play loud! The downside is that they are quite large, making it difficult for some people (like me) to justify and/or construct, and also fairly expensive which can be intimidating to first time builders. My solution was the "mini cum laude," a more budget oriented project with a similar layout (WWMT) and smaller footprint. The basic design uses dual SD215 8" DVC subwoofers (vented), a dayton PA130 as the midrange, and the hivi SD1.1 tweeter for the top end. It has an F3 of about 30hz, and a max volume of over 110dB (with about 100 watts) before woofer xmax becomes an issue. At no extra total cost, you can also use dual SD270 10" dvc subs sealed, which will give you another 3dB of sensitivity at the expense of a bit less extension (48hz F3), but with the floor and room gain I doubt this will be too big of an issue. In fact in smaller rooms, I'd wager the 8" version sounds too boomy due to small room gain. Also, since I have a feeling many will use this as part of a HT setup, if placed on either side of the TV and next to a wall the bass will be further magnified, making the sealed a better choice in this situation.
Cost for a pair if these is under $250!
Here's a rendering showing overall dimensions, layout, bracing etc. Since I did this one, I decided to build the midrange chamber onto one of the sides, so imagine the mid and tweeter shifted and moved over toward one of the sides. This simplifies construction and lowers baffle diffraction effects. Box is approx. 2.25 cubic feet after bracing and the mid chamber are taken into account, overall size is 11"X16"x36" which can be cut from a single sheet of 3/4" birch ply or MDF if you're careful about the cuts. Mid is open-backed t-line similar to the mini statements. I intend on heavily damping it , the lack of a rear wall is to reduce lower frequency standing waves, not to vent midrange into the room.
[IMGDEAD]http://www.flickr.com/photos/[email protected]/2189344342/[/IMGDEAD]
So I posted about this and did some sims and renderings, and a few people also wanted to see a more hifi version using a better mid and tweeter. Well there are hardly any reasonably priced midranges with high sensitivities, save the RS150, which seemed like it might work. For the tweeter I immediately chose the seas 27tdfc. I've used this tweeter several times and it simply can't be beat for the price. Low FS, low distortion, and $30. These two driver choices keep the sound quality high but the price pretty low. A bit (ok, a LOT) of crossover simulation later...
This simulation is for the SD270 woofers sealed, deeper extension can be had if using the SD215 vented (30hz F3), but at the expense of ~3dB of sensitivity. I'll have a simulated crossover for this version soon, but here's the SD270 version:
[IMGDEAD]http://homepages.nyu.edu/~msa286/laudehifixo3.gif[/IMGDEAD]
Price for drivers and XO parts is $350/pair, which is pretty cheap for a WWMT. This assumes using the jantzen p-core inductors for large values, NPE caps for large values, and poly caps and 18 guage inductors for the smaller values. I have a parts list I will post soon, everything but the tweeters (madisound) can be ordered from parts express. I know the parts count could be slightly reduced by being smarter about the notch filters, but it was flatter this way and not all that much more expensive so I think I'm going to leave the overall topology untouched.
I'll be building all four versions of this design, and I'll post my process and progress in this thread. I'll also be getting down and dirty with a measurement setup, so I'll be able to see how the results stack up against the simulations!
Please don't hesitate to offer any comments of suggestions, I hope this design can become popular to those with a somewhat limited budget or workshop, but who still crave a large, full sound.
Cost for a pair if these is under $250!
Here's a rendering showing overall dimensions, layout, bracing etc. Since I did this one, I decided to build the midrange chamber onto one of the sides, so imagine the mid and tweeter shifted and moved over toward one of the sides. This simplifies construction and lowers baffle diffraction effects. Box is approx. 2.25 cubic feet after bracing and the mid chamber are taken into account, overall size is 11"X16"x36" which can be cut from a single sheet of 3/4" birch ply or MDF if you're careful about the cuts. Mid is open-backed t-line similar to the mini statements. I intend on heavily damping it , the lack of a rear wall is to reduce lower frequency standing waves, not to vent midrange into the room.
[IMGDEAD]http://www.flickr.com/photos/[email protected]/2189344342/[/IMGDEAD]
So I posted about this and did some sims and renderings, and a few people also wanted to see a more hifi version using a better mid and tweeter. Well there are hardly any reasonably priced midranges with high sensitivities, save the RS150, which seemed like it might work. For the tweeter I immediately chose the seas 27tdfc. I've used this tweeter several times and it simply can't be beat for the price. Low FS, low distortion, and $30. These two driver choices keep the sound quality high but the price pretty low. A bit (ok, a LOT) of crossover simulation later...
This simulation is for the SD270 woofers sealed, deeper extension can be had if using the SD215 vented (30hz F3), but at the expense of ~3dB of sensitivity. I'll have a simulated crossover for this version soon, but here's the SD270 version:
[IMGDEAD]http://homepages.nyu.edu/~msa286/laudehifixo3.gif[/IMGDEAD]
Price for drivers and XO parts is $350/pair, which is pretty cheap for a WWMT. This assumes using the jantzen p-core inductors for large values, NPE caps for large values, and poly caps and 18 guage inductors for the smaller values. I have a parts list I will post soon, everything but the tweeters (madisound) can be ordered from parts express. I know the parts count could be slightly reduced by being smarter about the notch filters, but it was flatter this way and not all that much more expensive so I think I'm going to leave the overall topology untouched.
I'll be building all four versions of this design, and I'll post my process and progress in this thread. I'll also be getting down and dirty with a measurement setup, so I'll be able to see how the results stack up against the simulations!
Please don't hesitate to offer any comments of suggestions, I hope this design can become popular to those with a somewhat limited budget or workshop, but who still crave a large, full sound.
