First diy project: Bose buster

[augerpro]

For the 2.1 setup probably $270 for parts total. The MTMs are about $170 for the pair and the M8N subwoofer about $100. I keep running into delays so I've not finished these. The MTMs are veneered in a very cool pommele maple. It has that crumpled silk bedsheet look. I can't believe I actually pulled that task off. They look great but I think too easy for a newb like me to screwup. I was lucky. I'm waiting for the Pianolac to arrive so I can finish them up and post some pictures.

Currently I'm designing the WMTW center channel for this setup. After that I'll do the surround MTs but I won't actually build those. Unless I sell the system and the person really wants them. Since this is my first project it went alot slower than I expected. Some days I have to run to Lowe's multiple times for this or that.

[augerpro]

Here is the shots of the basically finished product:









The pictures don't do the veneer justice. In person it looks like a rumpled silk bedsheet. Very Cool. I still have to buff it out to glassy finish so I haven't been able to do a FR measurement and see how close it is to my model.
And it is possible to wrap a 1/42" veneer around a 1/2" corner! I preformed the veneer using super softener from joewoodworker. Great stuff. That and some patience and those little curved hobby scissors helped this noobie pull off my first veneer job! That said I wouldn't veneer anything this way again. It's way too easy to screw up the whole works. The seam at the front was pita. Unless you're really good with veneering I would advise either doing the baffle in black or veneering teh baffle and sides before the enclosure is built. That way you can do the routing after the veneer is on. You'll have a seam at the baffle and side panel though. Work is keeping me pretty busy so I won't have an FR until middle of next week.

I started on the center channel:





3way are no fun. I have several different XOs that are looking pretty good. If I have bump in the FR do you use and LCR in series with the driver if it's in the passband and LCR to shunt if it's out of the passband? I'll post my XO's later and you can see what I mean.

[---k---]

Wow. Very impressive. You should be proud.

[augerpro]

Wow. Very impressive. You should be proud.

Thanks! I am proud of them actually. They have there have their flaws, but considering beffore this project I didn't know what a XO was and the last time I touched a table saw was in junior high, I am pretty satisfied with the result. The whole project was really to cut my teeth on speaker design/building so I couldn't ask for more.

Here is the center channel XO I've been working:





And reverse polarity:





The impedence hits 3.43 around 245 Hz. Is this a problem?





Keep in mind this is just a first pass at the XO. Blue driver indicates it is connected reverse polarity. What do you guys think of using the resistor on the mids? I do have a version without the resistor but I just can't get the FR I want without the impedence dropping too low. I'll have to keep working that one though. Also what do you guys think of the LCR on the tweeter? I used to put a notch at 2.5k because I had some bad peaking there. It's baffle related and there is just no way lessen it by moving the drivers around since I have little room for adjustment. Small baffles are kind of hard to work with as far as baffle diffraction. I'm not sure when you use this kind of LCR in series with the driver versus one to shunt.

[cjd]

I'd try to do without the R on the mid. Try smaller gauge inductors. E-mail me frd/zma files and I may find some time to mess with it a little. I've been away a bit too long to remember exactly what I'd mess with from here :|

C

[augerpro]

You've got mail Chris!

I got rid of the resistor on the mid and dropped to a 2nd order topo on the woofer. Resistor values for inductors are fairly close to real world








And Z is above 4 ohm!!! What do you guys think of the low Z above 20k? Bad or not?

[Mudjock]

That low Z above 20 kHz could be a slight problem, but really not too bad...

At very high frequencies, that parallel RC (C12, R13) in parallel with the tweeter becomes a dead short, but at least everything still has to go through R11 - so you'll never drop below 3 ohms. If you want to further mitigate that, you could raise the value of R11 and add a resistor in series with the parallel RC shunt leg. With a little trial-and-error, you should be able to get nearly the same response and a higher hf impedance.

[augerpro]

I think I'm getting close to a final XO. Mudjock I tried your idea and it worked very well. After about 15 minutes of tweaking Z is great and I only lost .5 dB from 3k-15k at most, barely noticeable.

I also tried the bandpass layout preferred by JonM. I believe it's referred to as a T-bandpass. This made huge difference. Z came up and I could use smaller components for the HP section of the bandpass.

Here are the results. Reverse polarity graph is offset -1 dB for clarity.






Also I measured the drivers again with a piece of plywood under the speaker to simulate a 48" tv. the bottom of the speaker was 4" from the top of the plywood as it would be in my living room because the center channel sits on shelf just above the tv. I don't know if this kept it from "coupling" effectively with the plywood but the difference was minimal. Or maybe I was just expecting too much of difference. Anyway here are the results of that, before I added Mudjock's tweeter tweak:

[augerpro]

So no one has any thoughts? My main concerns are the notch filters and my implementation of them.

Also the phase correlation of the mid and woofer isn't great. Although considering the driver layout and the measuring distance of 1 meter I thinK I may remeasure from 2 or 3 meters and see if it looks better.

[cjd]

Driver size and proximity should make a 1M measurement good on the "woofers" here.

I have been sick and between naps I've neglected to pull your files together. However, I think you should be able to simplify things and do without the notch filters.

Looking good, regardless.

[tyler]

Those really turned out nice! Excellent job on the Veneer. :T

[augerpro]

Thanks Mr. Durden!

I did some more tweaks and inputted actual component values from PE.








Pretty close to finished I think unless Chris or David get back to me with some ingenius changes. Thanks to everyone who has helped with this project so far. htguide is the bestest ;x(

[augerpro]

deleted

[augerpro]

Well I've finished the XO for the CC. Here is the actual (red) versus the modeled (black) frequency response, 1/24 smoothing:





Woohoo! I can't ask for closer than that! I didn't splice in a nearfield for the low frequencies so you'll just have to trust the model is still accurate there. FINALLY done with this project. Except the sub and the veneer of the CC. When I connected the drivers to teh XO I accidently wired the woofers as positive, here was my first measurement like that:






Well at least I know I have good phase integration of the woofer and mid! Now I'll have to throw in Revenge of the Sith and see how it sounds!

[PoorboyMike]

Still waiting on the review. :B

[Gir]

Must be good enough to still be watching it :T

[augerpro]

No review yet of the center channel since I just finished it. But the little MTM's are great! My friends were laughing because they couldn't believe how loud they could get--and still sound good. They kept putting their ear to my Rocket 760's and Bigfoot because they didn't believe it was those little speakers making all that sound.

Now the tweeter distortion is audible and they do compress a bit at higher levels. But considering the cost and the level, probably 100-103ish dB, I can't complain.

Overall I'm very satisfied with them, especially since it's my first design ever.

[cotdt]

not to spoil the party, but in order to be a "Bose-buster", shouldn't it also be the same size as the Bose cubes?

[Hdale85]

What are the dimensions of that center?

[augerpro]

What are the dimensions of that center?

I'll copy my email to dawaro here so everyone has the details:

I don't have any CAD program so I'll just give you the placement of the drivers in (x,y) like you were graphing it ok? lower left of the enclosure is (0,0).

For the MTMs: enclosure is 10 1/2"h by 4 1/4"w, this includes the endcaps. Bottom woofer is at (2 1/8", 2 1/2"), tweeter at (2 1/8", 5 1/4"), and top woofer at (2 1/8", 8"). Depth is not real critical. I went 8" deep (inside the box, 9" overall), you can go more, although I wouldn't go much less. I'm pretty much at the minimum volume I would use for these. Line the walls appropriately and you can add some fill, not alot though. R12 can be modified. At 1.5 ohms the sound is more laidback, remove it altogether and the sound is brighter. I liked it removed the best for the clarity, but it can get a bit fatiguing that way. These sound really quite good for the size. My friends were laughing when they heard them, they couldn't believe all that sound was coming from these little speakers! Cross them at 150 Hz to sub. These can't play low so don't try it.

For the Center Channel the enclosure measures 6 3/4"h by 15 1/2"w. The woofers are at (3", 3 3/8") and (12 1/2", 3 3/8"), mid is at (7 3/4", 2 1/2"), and the tweeter at (7 3/4", 5 1/4"). The depth is 12" (11" inside the box). The mid is in it's own little enclosure. The mid volume is about 1 liter, heavily filled. You can go bigger here but since it's a mid it doesn't need alot of volume. The tweeter shares the same small enlosure as the mid. The woofers are another story they are very high Q. The box volume is smaller than is optimal. If you can go deeper than 12" I would do that. Fill heavily. Right now I have 3 dB peak around 100Hz because of the Qtc. However I just lined the walls for the prototype, so you should be able lower that with the fill. The last XO I posted is correct. Cross between 100-150 Hz to the sub. This is the prototype that i measured with the XO outside the box, so if I were you I would definatley try to make the speaker deeper so you have some volume to throw away on putting the XO inside.

The tweeter is just slightly bigger than 1 3/8". I used a 1 3/8" forstner? bit and then sanded. The tweeter isn't quite 1/2" tall so you will have to grind down or route the back of the baffle where the tweeter flange is so the front of the tweeter is flush with the face of the baffle. After you cut the hole and put the tweeter in you''l see what I mean. All woofers are flush mounted.

I cut the endcaps 1/4" oversize so they overhang the edge by 1/8" on all sides. Then I used 1/8" roundover on them.

Green driver icon is normal polarity and blue is reversed polarity. All caps were Dayton and all coils were Jantzen, mostly 18 guage, but one or two 15s for the big inline caps I think


Hope that helps!



EDIT Added 5/12/2007 Final XO schematics- BLUE DRIVER(S) ARE WIRED IN REVERSE POLARITY!

MTM schematic and component list:











WMTW centerchannel schematic and component list:









EDIT 8/30/07 Baffle layout added

[augerpro]

not to spoil the party, but in order to be a "Bose-buster", shouldn't it also be the same size as the Bose cubes?

They're close...ish! The MTMs are about the size of the Denver yellow pages, not quite as deep.

[Gir]

You should put a writeup in the mission accomplished forums. Great job! I might have to build a few of these for my parents. They're using a Sony "dream system" or whatever that crap is... meh.

[augerpro]

You should put a writeup in the mission accomplished forums. Great job! I might have to build a few of these for my parents. They're using a Sony "dream system" or whatever that crap is... meh.

Oh heh, I don't know if this MA worthy ops: , but thanks! :T I do agree something like this should be there though. Alot of new people come by this forum checking out the diy thing and I think it would be nice to have MA projects that represent alot of "genres" if you will. For example if Dan N's omni pans out that should be included. I mean that's a cool speaker! Thomas and JonM should showcase more of the designs that happen here, I think that is one thing that seperates this forum from the other ones. Just my .02

[garto]

I'm having a hard time trying to figure out the crossovers for some reason. Is there anyway you could edit your actual picture of the crossovers with paint and write in the values of each of the components. I know its spoon feeding but it would help me a lot.

[augerpro]

hmmm... I could use a different format but it will take a couple days. What specifically are you having a hard time with?

[Dennis H]

Auger, maybe just a bit bigger pic of the XO -- crop everthing else out. I find myself squinting to make out the components.

[augerpro]

Ya teh image doesn't blow up well. I'll try another program, maybe Speaker Workshop or even Paint.

[dawaro]

Bose Buster WMTW Schematic

Ya teh image doesn't blow up well. I'll try another program, maybe Speaker Workshop or even Paint.

How is this??

[dlneubec]

Ya teh image doesn't blow up well. I'll try another program, maybe Speaker Workshop or even Paint.

Brandon,

Here's what I do in SE. Turn off both Cad nodes and Schem nodes at the bottom left of the Cad editor. This cleans up the screen a lot for screen captures. I also downloaded a program called MWSnap 3 (freeware), which is very easy to use to capture a specific window, etc. and save the files in the Gif fromat. Here is an example. They are small files and very readable (when you expand to full size). This one is only 45kb or so.

[Dennis H]

How is this??

Looks like you need to flip W1 over so the two woofers are in phase with each other and the other drivers.

[dawaro]

Looks like you need to flip W1 over so the two woofers are in phase with each other and the other drivers.

I think it is just W2 that needed to be flipped. If I remember right Auger said the phase on the woofers are reversed.

[augerpro]

Very nice David! I think that is the most readable option. What program is that? Do you mind if I move that over to one of my other posts? And the woofers are wired correctly.

Thanks guys for the help.

[garto]

Thanks Dawaro, that's precisely what I needed. And thank you Augerpro for sharing with us your great new speaker.

[dawaro]

Very nice David! I think that is the most readable option. What program is that? Do you mind if I move that over to one of my other posts? And the woofers are wired correctly.

Thanks guys for the help.

That is the schematic from LspCad. I will try to get one put together for the MTM and you can put them in your original post. I still plan on doing the enclosure drawing for you just havent had a chance...

[augerpro]

Dan I used your tips and tricks in Paint. Works well I think. I added some new jpgs of the XO and added it to post 65:

https://htguide.com/forum/showpost.p...8&postcount=65

Is that clear enough now?

[dlneubec]

Looks readable to me!

[PoorboyMike]

I have the center up and running and it sounds pretty darn good. It doesn't go very deep but it's very clear and off axis listening is great. It's also very detailed, much more so than my Infinity Alpha36c.

Anyway, the dimensions I used were 18wX7hX13d. I went a little bigger than Brandon because of the high qts of the M4N. This also gave me plenty of room for the xover (it's big!) and a little more space for the mid enclosure. The inside is lined with 1/2 sonic barrier. Not the best stuff but I got a heck of deal on it at the PE showroom. Never mind the cigarette burns. :B
















And here is a pic of the MTM boxes next to the M8N Mini-Ariel SW sub thingie. I'm going to tune this to about 34hz and use it for my new work sub, along with the BoseBuster MTM's. Should be able to get a little more spl out of this set up than my current B3S full range/TB 6.5 set up. Oh, and don't look at my messy shop. I've been cutting a lot of wood and haven't cleaned it up good in a couple of weeks. ops:

[augerpro]

That's awesome Mike! I'm SO happy you're satisfied! Are you going to finish any of these? That sub would look great veneered like teh SW12. Very sharp.

[PoorboyMike]

That's awesome Mike! I'm SO happy you're satisfied! Are you going to finish any of these? That sub would look great veneered like teh SW12. Very sharp.

I picked up a roll of Band-it oak veneer for the MTMs and the sub. I'm also going to try using solid oak for the baffles. Not the best thing to use but I think it will be fine for what I'm using them for. I was going to use everything to replace my current work system, but the center is just too big to fit between my keyboard and the wall. I'll probably end up selling it but not because I don't like it. You did a great job designing these Brandon!

[PoorboyMike]

New work system is up and running. This system sounds much better than my old B3N/TB6.5 set up.











Still waiting to hear from ThomasW on the PE feet. I made an Ariel like base for the sub but thought it might look better with the feet.

[---k---]

So you're "that guy" with a subwoofer in his cube at work.

Very nice work. I'm sure your coworkers are jealous.

[PoorboyMike]

So you're "that guy" with a subwoofer in his cube at work.

Very nice work. I'm sure your coworkers are jealous.

Hey, it's only an 8" and the driver isn't technically a "sub". :B Still sounds pretty darn good though and the night shift guys sure like them.

[augerpro]

See now THAT'S what I envisioned when I started this project! Except you had the woodworking skills to actually pull it off ;x( ! Very nice Mike :T Did you use solid wood all around? What kind? What do you think of the sound? Did you pad down the tweeter like I mentioned?

I'll tell ya Mike, your woodworking, especially on the big sub you built for a friend, really inspires me to make my projects "furniture quality" too!

[augerpro]

Hi guys. My mom just bought "one of those fancy bigscreens" and asked to make some speakers for her so she can watch her concert DVDs and listen to music. She liked my original project here but thought they were a too big 8O So I set to make something she'd like. I decided to use the Aura NS3-194 because, well, I had some on hand...and they are somewhat capable of running fullrange, were on sale, sound decent (really), and with a tiny VAS and neo motor can fit in tiny boxes. Since people are all spread out in that living room I decided to go 2 way with just the center channel, so voices would be clear at all angles. I used the little Aura ti neo tweeter for the center. And I went with the TangBand W6-1139 for a sub. It's 15.5L net tuned to 30Hz, powered by the Dayton 75W plate amp.








Center channel response:





Here is onaxis (blue) of the fullrangers and about 30 degrees offaxis (red). I wanted to get high quality sound, but also wanted to keep costs low, so had accept less than perfect response, at least on axis. Listening position is off axis, and the response looks pretty good from there...





Anyway, darn fun little project. The sub is crossed to the mains at 150Hz and puts out a heck of lot of bass for small sub. And the fullrangers really do sound decent. I was surprised.

[Dennis H]

Nice Brandon! On the boards we tend to forget that most people will be perfectly happy with a system like that and don't really understand or care about our obsession with audio gear.