Dual hi-vi mini project

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Ok so i'm heading off to college for areospace engineering and airforce ROTC in about a month and i'd like to shrink my stereo a bit. I currently have 4 polk audio r15's, a polk cs1 center, yamaha 10 inch sub and a pioneer reciever.

I've been doing research into speaker building for about 3 weeks now and I think i've finally gotten to the point where i'm ready to try.

My goals are to beat the clarity of the polk r15's in the mid and high area's and allowing my sub to take the low end (sub 200hz range). My neighbor has bassbox pro so i have have access to graphs and box design and the such. I do some audio editing and creation and strongly prefer a completely flat response to anything else.

Each speaker (2 total) are going to be comprised of 2 mids and a tweeter. At this point i'm stuck between the m4n and the m3n. The m4n's seems to be overpowered before 200 ( so it's not a big deal) and then a flatter response out to 5k which is where i'd like to cut them. For the tweeter i'm not really sure. i'm thinking about the hi-vi sd1 right now

I'm totally stumped when it comes to crossover options or desing. I could build my own without a problem (soldering is no problem at all even .05 pitch and smd's) but i don't know how to go about it.

any suggestions? I have 3 weeks to get this done
 
I'm going to make a few assumptions given the information available. One is that you would like something small and inexpensive. Two is that you don't presently have access to or experience with frequency response measurement equipment, though I'm sure you seem willing to learn. Three is that you will be trying to pack a lot of stuff and see a lot of friends in the next three weeks and that you will not be able to spend a large amount of time on this project.

Based on the time limit (3 weeks) and the lead time to get parts which will eat up a minimum of one week, I would highly recommend building an already published design if you want to have a finished pair of speakers by the time you leave for school.

I realize that this suggestion removes some of the romance from the speaker building dream, but the reality of the situation is that even for an experienced speaker designer, 3 weeks would be an insufficient amount of time to properly design and build a speaker, if for no other reason than lead time alone in ordering parts.

A nice design is the bargain mini at zaphaudio.
http://www.zaphaudio.com/ZBM4.html

This design has already been thoroughly tested and was designed by a very reputable source. It has very flat response and is perfect for use with a subwoofer.

You can always build more speakers later if you want to design your own, it can be very rewarding and a great way to get some engineering practice.

Best of luck with the project, which ever way to decide to go; and best of luck with school as well!

Regards,
David
 
I just noticed that the woofer used in Zaph's project is on sale at MCM. Use coupon code WA807 to get it for $9.95 (regularly $12.95). You can also get $4.99 shipping right now for orders over $50 and free shipping for orders over $100.

It is a little known fact that MCM carries Bennic capacitors as well (the brand carried by Madisound and the ones in the bill of materials for the bargain mini), and that they are often cheaper than Parts Express or Madisound.

Bill of Materials for the Bargain Mini as purchased through Madisound.

C0 - 2.7 uF Bennic Poly $1.30 ea
L1 - .25 mH 19 ga Air Core $2.75 ea
C3 - 10 uF Bennic Poly $3.75 ea
R4 - 4 ohms Eagle Metal Oxide Film $1.20 ea
R5 - 5 ohms Eagle Metal Oxide Film $1.20 ea
L7 - 1.50 mH 19 ga Air Core $5.40 ea
C9 - 3.3 uF Bennic Poly $1.60 ea

Prices at MCM (using current 15% coupon code)

C0 - 2.7 uF Bennic Poly $1.15 ea
L1 - .25 mH 19 ga Air Core (Not Available)
C3 - 10 uF Bennic Poly $2.63 ea
R4 - 3.9 ohms 25W Wirewound Resistor $0.74 ea
R5 - 5.1 ohms 25W Wirewound Resistor $0.74 ea
L7 - 1.50 mH 19 ga Air Core $5.64 ea (Cheaper at Madisound)
C9 - 3.3 uF Bennic Poly $1.44 ea

You still have to place an order to Madisound for the tweeters and inductors, but if you order the rest of the parts from MCM you can save another $4.22, on top of the $6 you save for the woofers being on sale.

The total for the components and drivers could be as low as $85 or so including shipping from both MCM and Madisound.

Best Regards,
David
 
A wise choice, I think you will find the build enjoyable and rewarding.

You should read the whole zbm4 page carefully, and there is at least one other thread on this forum where someone built the zbm4 and documented the build. While you are on Zaph's page, read the design mantras article to get a feel for how Zaph designs and builds his projects.

The biggest challenge on this project will be building the enclosure. You will probably want to go ahead and start on that as soon as possible, which you can do without the drivers since you have detailed drawings on the zbm4 page. Do you have a router and table saw? If not you might consider pre-built enclosures. These can be rather pricey, but are worth every dime if you don't have proper space/time/tools to do woodworking yourself.

Go ahead and start compiling your order(s) for the parts, if you are anything like me you will need a day or two to add on all the extras you might feel compelled to order.

I was wrong earlier about the shipping cost for MCM. It looks like you only have to have a minimum order of $40 to get the discounted $4.99 shipping, which should work out perfectly for you if you order the capacitors, woofers, and the 1.5mH inductor from them.

I found a 20% off code for MCM, which makes the deal even sweeter. The source code is FF020 . You will need to enter both source codes (FF020 and WA807) to get the sale price on the woofers in addition to the 20% off.

Good luck on the project and be sure to ask any questions you have and give us updates!

Regards,
David
 
I hate to butt in but you've given some great advice gtforme00, just the advice I was about to register and ask for.

Big question: Where did you find the Bennic caps and other parts on the MCM site? I've tried searching all over and can't locate any of the components you mentioned other then the speakers. If you still had the part numbers that would be fantastic.

Thanks!
 
Not a problem, try this link: http://www.mcmelectronics.com/browse/Crossover Component/1000296

MCM doesn't list Bennic as the manufacturer, but if you look at the pictures you can tell that they are, and the manufacturer part number is a Bennic part number. More importantly, I have ordered them in the past and can confirm that they are Bennic branded.

MCM isn't the easiest site to browse, so sometimes searching for keywords and using filters is the only way to find what you need.

Most of the crossover components on the MCM site are listed under AMS Enterprises as the manufacturer. You can select to list items by manufacturer to help narrow the list.

Regards,
David
 
ok well i have all of the parts ordered.

so i have a box coming from madi, mcm, and parts express.

as mine are going to be near a wall i'm going to be doing a front ported design and instead of the closed cell acoustic foam he used inside the box i'm going to be using that ascustafluf from Parts express. I've used it in a few fiberglass sub enclosures i made and it's awesome.

I've attached the design i've made from zaphs baffel but with a front port
 

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It probably would have, but it appears to be out of stock.

This inductor is the one I had in mind when I made the list:

http://www.mcmelectronics.com/product/50-725

I don't know what gauge it is, but its probably 18 or 19 gauge. It doesn't really matter a whole lot unless you use a iron core inductor and the dc resistance is REALLY low, then you may need to change the tweeter resistors to match the increased output of the woofer.

By the way, the 20% off code ends today! So get your orders in quickly if you want the extra percent off. The 15% code I have ends on August 9th, so all is not lost if you miss the boat for the 20%.

-David
 
I couldn't resist.

I placed an order for some of the 5" aluminum woofers (same family as the 4" in the zbm4), along with a load of different capacitors and resistors.

My total came to $135, and it says I "saved" around $60 (plus $15 more for the free shipping). Not too shabby...

I'm going to try a slightly larger brother to the zbm4, with a 5" aluminum woofer and a 1" aluminum dome from the NHT surplus deal.

When I start making sawdust I'll post a new thread with the design. First I need to have a yard sale and make some space in the garage!

-David
 
for the tweeter hole i'm not to sure yet. I may have access to a correct size drill bit but i have to talk to a few people. I'm going to route everything else.

ALL of the parts are showing up on tuesday and i'm going to get wood tomorrow. I picked up a few sheets of 1/2 inch but i'm going to build a vacuum former with that instead to make fiberglass molds.

So i'm hoping to have all the pieces cut by monday then work on the baffel for 2 or so days. I'm also going to shellac seal the mdf then prime and sand then paint probably black. Most likely i'm going to hvlp it.

So when i start doing stuff i'll make a build thread with all the cad files i've made and such.

For a while i was thinking of designing a PCB for the xover and having a few made but i don't think it's necessary
 
A PCB for a passive crossover is a luxury. It would look professional I'm sure; but is neither an easier nor a faster way to get it done. The results once you hide the board inside the speaker will be no different than point-to-point wiring. This is not a particularly complex crossover and should be simple to do on a piece of masonite (the kind with peg holes for hanging tools), I've even used cardboard in a pinch and just punched holes with an awl where the part leads press through. A little hot glue to hold things in place and you are done.

That said, a little planning of the crossover layout will make things easier and faster. You might want to sketch out how you plan to orient the parts so that you can wire things more easily. Another thing to consider is that inductors can magnetically couple fields if placed too close and in the wrong orientation.

User cyberspyder had a thread on this exact topic for an extremely similar speaker build.

Inductor Placement Thread

Build Thread

Hope that helps,
David
 
Just got my parts in!

A couple of comments.

1. The 1.5mH inductor is 18AWG and is nicely made.
2. The "Audio Grade" capacitors are still Bennic (a good thing).
3. The nonpolar electrolytic capacitors are extremely small in size relative to what I am used to from Madisound (Bennic branded and very hefty) or even Parts Express (which are smaller than Madisounds and feel comparatively cheap). They look cheap, but I have yet to test them. Of all of the nonpolar electrolytics, I like the ones that Madisound carries best. At least, I feel like I am getting more for my money even if they don't test differently :D
4. Two of the stamped frame woofers (55-1870) I ordered had bent frames! They were just thrown in a small box with no cardboard bracing like most woofers have. I called MCM and they are sending me two new woofers at no cost, a settlement which has completely amended the situation. The cast frame woofers (55-3855) survived shipping with much less damage, just a little compression to the surrounds which should relax out in a few days.

Its like Christmas day here, with all kinds of new toys to play with. I hope you are having as much fun as I am with your project!

Regards,
David
 
I'm super curious about the MCM cast frame jobbies, I'll be interested to know your impressions.

I'd be interested in a bargain-mini design update that included the cast frame woofer, and the PE tiny tweeters that he was talking about working up when the ti tweeter was out of stock.
 
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