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post #1 of 26 Old 04-16-2007, 10:19 AM - Thread Starter
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Hi all,

I am looking to do my first DIY speaker. Done subs, but want to try a nice pair of speakers now to use in 2 channel for mostly music, maybe 12-18" tall, so its easy to sit on desk at work.

I have access to a CNC mill, which means I can whip up some pretty cool stuff easily, so I am thinking of doing an open baffle design, so I can cut something out of sheet metal easily.

I would like to do it all with some speakers from partsexpress, madisound, or similar, and not be too expensive.

Does anyone know any existing projects for open baffle speakers?

I would also consider mixing open baffle with a closed section, since I know open baffle you sacrafice a lot of low end. Maybe put one of those 5" or 6.5" tang bands in it. I am not really sure how to design a speaker, so any help anyone has would be greatly appreciated!

Thanks.
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post #2 of 26 Old 04-16-2007, 10:49 AM - Thread Starter
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Would any of these be a good place to start:

http://www.partsexpress.com/pe/showd...number=295-600
- 5 1/4"
- Qts: 0.54
- Looks great!
- $49

http://www.partsexpress.com/pe/showd...number=297-420
- 6"
- Qts: .51
- Looks okay
- $64

http://www.partsexpress.com/pe/showd...number=295-605
- 6"
- Qts: .83
- Looks so-so
- $26

http://www.partsexpress.com/pe/showd...number=296-190
- 6 1/2"
- Qts: .59
- Looks great!
- $54

http://www.partsexpress.com/pe/showd...number=296-192
- 6 1/2"
- Qts: .70
- Looks so-so
- $18

http://www.partsexpress.com/pe/showd...number=264-422
- 6 1/2"
- Qts: .80
- Looks so-so
- $21


I was trying to find good sized drivers with high Qts. I am not sure what other qualities will be good for an open baffle design. Also, I do not know what to look for in a tweeter for open baffle. Am I getting myself anywhere?
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post #3 of 26 Old 04-16-2007, 10:58 AM - Thread Starter
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Maybe use 2 or 4 of these per side?


http://www.madisound.com/cgi-bin/ind....5636&pid=1832
- 3"
- Qts: .86
- Looks good
- $10

or

http://www.madisound.com/cgi-bin/ind....5636&pid=2170
- 4"
- Qts: 1.08
- Looks good
- $19
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post #4 of 26 Old 04-16-2007, 11:31 AM
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www.gr-research.com

The OB-5 is a great speaker. Bigger than what you want though.

If you want really good low end performance look at the OB-7. Huge, I know, but there's a solution for that. Leave off the subwoofer and move the upper two woofers down to the bottom. So you end up with a OB-5 that has four woofers instead of two. The standard OB-5 is ported for the woofer section, if you do the hybrid design it's sealed.

And if you leave the rear enclosure off the top section you wind up with something that looks like this.

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post #5 of 26 Old 04-16-2007, 11:41 AM - Thread Starter
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Thanks for the link wallywest. Those are definitally nice. Still, those are way outside of my budget. I am thinking 200 max for drivers, crossover, and any materials I need. 100 would be ideal.
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post #6 of 26 Old 04-16-2007, 04:21 PM
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Quote:
Originally Posted by mastarecoil View Post

Thanks for the link wallywest. Those are definitally nice. Still, those are way outside of my budget. I am thinking 200 max for drivers, crossover, and any materials I need. 100 would be ideal.

I used this for an open baffle speaker. I has a pretty wide bandwidth but definately needs some low end augmentation. I built something to do just that using an 8" DVC woofer. Were I to do it again I would have built two augmentation speakers with some other 8" driver - maybe a Dayton RS or something.

If you have a $200/pair budget make sure you price out what a 3-way crossover would cost to build.

BTW I also thought it would be neat to use an array of Hi-Vi B3N's with something else for the low end but it's sensitivity is very low and you really would need an array. Also, I was always concerned that the motor structure blocks the rear of the driver too much. Maybe an array of these? You could almost use them as tweeters to make the crossover simpler / cheaper.

Just some thoughts.
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post #7 of 26 Old 04-16-2007, 05:22 PM - Thread Starter
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Thanks boomie. I actually read your thread and was interested.

I really liked the B3N 3" also, and think it would be really neat to have an array of those, something to help out the low end, and a good tweeter. I think you are right, though, it would be an expensive crossover. Maybe I will put this project off until I can extend the budget if I come up with a good design. Otherwise I am leaning towards the Dynavox woofers, either 5 1/4 or 6 inch, and pairing it with a good tweeter. I just have no idea how to design speakers like that.
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post #8 of 26 Old 04-16-2007, 05:33 PM - Thread Starter
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Actually there is the B3N, B4N, M3N, and M4N that all look good.

http://www.partsexpress.com/webpage....&so=2&desc=ASC

Same with some of these tang bands, they look good
http://www.partsexpress.com/pe/showd...number=264-813
http://www.partsexpress.com/pe/showd...number=264-817
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post #9 of 26 Old 04-16-2007, 07:38 PM
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How about this?

(4) Tangband W2-880SD ($52)
(1) Dayton RS225S-8 ($40)

Crossover @ apx. 1000Hz apx. $25 There is enough overlap that a second order LR should work okay.
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post #10 of 26 Old 04-16-2007, 07:49 PM - Thread Starter
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That dosent look too bad. Would using 4 of those 3" HiVi speakers work as well? Would there be no need for a tweeter?
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post #11 of 26 Old 04-16-2007, 08:05 PM
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Quote:
Originally Posted by mastarecoil View Post

That dosent look too bad. Would using 4 of those 3" HiVi speakers work as well? Would there be no need for a tweeter?

I don't think the Hi-Vi B3N plays high enough to be a good tweeter but it depends on taste I guess.
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post #12 of 26 Old 04-16-2007, 08:06 PM - Thread Starter
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The tang 2" would play high enough to be a good tweeter? Or could I add a tweeter to the B3N?
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post #13 of 26 Old 04-16-2007, 08:27 PM
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It modles well.
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post #14 of 26 Old 04-16-2007, 08:45 PM - Thread Starter
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What do you use to model these?
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post #15 of 26 Old 04-16-2007, 09:06 PM
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Quote:
Originally Posted by mastarecoil View Post

What do you use to model these?

I use Unibox and Passive Crossover Designer. WinISD is also popular. All three of these programs are free.
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post #16 of 26 Old 04-16-2007, 09:16 PM
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For open baffles, The Edge works well. Check the 'open baffle' box in the software to simulate the dipole response. Add the baffle effects predicted by The Edge to the drivers' response.

http://www.tolvan.com/edge/

Dennis H
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post #17 of 26 Old 04-16-2007, 09:34 PM - Thread Starter
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Thanks, I will check these out.

What are the differences (cost wise) in a 3 way crossover compared to a 2 way? It would be nice to add a tweeter also.
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post #18 of 26 Old 04-17-2007, 12:12 PM - Thread Starter
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Thanks for all the help so far. I really appreciate it.

The more and more I look at them, I am loving these Hi-Vi speakers.

Now I am thinking to postpone this project until I have the budget, and turn it into a MMTMMW design, or maybe just a MTMW.

Use the B3N (or M3N) for the M, will have to select a tweeter, but initially the Hi-Vi RT1C-A Planar Tweeter looks good. Not sure about the woofer. Keeping with the copper colored Hi-Vi speakers would be nice, but the options (like the M5a, M6a, M5N, or M6N) dont seem very impressive.

Hopefully soon I will learn how to model this all. Would using two woofers help me much? Or even is this a good idea at all?
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post #19 of 26 Old 04-17-2007, 01:43 PM
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Quote:
Originally Posted by mastarecoil View Post

Thanks, I will check these out.

What are the differences (cost wise) in a 3 way crossover compared to a 2 way? It would be nice to add a tweeter also.

It would double the cost of the crossover and add the cost of a tweeter. Still do-able without going too far over budget.

Quote:
Originally Posted by mastarecoil View Post

Hopefully soon I will learn how to model this all. Would using two woofers help me much? Or even is this a good idea at all?

No rush, but there is also no way better to learn then to just jump in and do it. If you like it you will start looking for flaws in this design so you can justify "improving" it later!

As far as having two woofers - you can certainly go that route if you want but because of the lowish sensitivity of the B3N drivers you probably won't need to.
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post #20 of 26 Old 04-17-2007, 02:02 PM
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I hope this isn't considered thread-jacking, but I fear it might be. Ow well - I apolgize.

Wally, I noticed that you suggested an "OB-6" type of design. Did you do this? Did you simply place 4 drives in the bass bucket of the OB-5 enclosure?

Interesting. I thought about using two M-165x drivers instead, using a bigger ported enclosure in order to get that lower response.

If you built this, I'm curious to hear your impressions, and if you know they compare to "standard" OB5s. Thanks.
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post #21 of 26 Old 04-17-2007, 02:23 PM - Thread Starter
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Would there be a big difference (performance wise) between a TMMW and a MMTMMW design?

I think I can only get these speakers in 8ohm, so a TMMW would have a 8ohm tweeter, 4 ohm with the two mid, and 8 ohm woofer. Can the crossover be made to compensate?
The MMTMMW design can be 8ohm all the way.

I posted similar over at diyaudio and the B3N gets a lot of praise there, which is part of the reason I am leaning towards it.

I would easily have 250-300 in this project before its done, it sounds like. How do you think these speakers would compare, in the end, to a pair of av123 x-ls? Is it going to be close, or am I missing a lot?
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post #22 of 26 Old 04-17-2007, 02:31 PM - Thread Starter
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I have used WinISD before, for subs, but now am having a hard time for this. How can I make an open baffle model?
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post #23 of 26 Old 04-17-2007, 03:10 PM
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Quote:
Originally Posted by mastarecoil View Post

I have used WinISD before, for subs, but now am having a hard time for this. How can I make an open baffle model?

As I noted in post #16, download The Edge. It assumes 'perfect' drivers but it will show you what happens as you change baffle size and shape -- a MUCH bigger effect than changing T/S parameters.

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post #24 of 26 Old 04-17-2007, 03:30 PM - Thread Starter
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Okay, I will play around with that one more.

I had a real specific baffle design in mind. I hope it works okay.
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post #25 of 26 Old 04-17-2007, 03:33 PM
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Here's a screenie from The Edge. It's fast and super easy to use. Drag things around on the baffle sketch and watch the frequency response change.


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post #26 of 26 Old 04-17-2007, 04:01 PM
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Quote:
Originally Posted by mastarecoil View Post

Would there be a big difference (performance wise) between a TMMW and a MMTMMW design?

I think I can only get these speakers in 8ohm, so a TMMW would have a 8ohm tweeter, 4 ohm with the two mid, and 8 ohm woofer. Can the crossover be made to compensate?
The MMTMMW design can be 8ohm all the way.

I posted similar over at diyaudio and the B3N gets a lot of praise there, which is part of the reason I am leaning towards it.

It's more then just having a level impedence. The sensitivity of the B3N isn't super great so you'd either have to get real inefficient woofers or pad the hell out of them. I think the finished product would sound much better with MMTMMW, all 8 ohms - it's only a $20/speaker difference. Oh, it will also look cooler.

Quote:
Originally Posted by mastarecoil View Post

I would easily have 250-300 in this project before its done, it sounds like. How do you think these speakers would compare, in the end, to a pair of av123 x-ls? Is it going to be close, or am I missing a lot?

That's a pretty subjective question and no amount of modelling will really answer that. I personally think if you spend some time modelling and tuning you'll get something sounds just as good - but different. The x-ls are excellent speakers, but they can't do an OB sound because they aren't OB. Also, having the luxury of doing a 3-way design means you can select a woofer that will dig deeper. Plus, store bought speakers garner only a fraction of the bragging rights!
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