# First project: Paradigm-like Surrounds



## Owen Bartley (Oct 18, 2006)

Well, my Loudspeaker Design Cookbook has arrived, and I think I'm ready to give myself a project. Before I try anything too critical, I thought I'd build a pair of surrounds, since I don't have a proper pair for my SB channels anyway.

I'd like to build something with the following goals in mind:

somewhat match my current Paradigm Monitor setup
fairly shallow cabinet
inexpensive components
bi- or dipolar design for a more diffused sound
drivers available to order in Canada would be a big plus
probably a sealed design
woofer/tweeter or woofer/2 tweeters

They will be driven by a Denon receiver putting out about 75wpc until I can convince myself that I need to take a step toward seperates and get a multi-chan power amp. This will be more a learning/practice exercise than an attempt at perfect fidelity, so I can bend on the parameters. I've been looking at the kits, and haven't seen anything that stood out as a great match for what I have now, so if anyone either knows of a driver combo that sounds similar to Paradigm's Monitor line, or has built some bi- o dipole surrounds that they like, feel free to make suggestions!


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## JorgenMan (Aug 16, 2006)

I'm not very knowlegdeable about dipole/bipole surrounds, so forgive my ignorance. The two-tweeter/one-woofer idea is to get a more diffused sound, right? I assume both tweeters face away from the listening position. Also, will these be stand-mounted or wall-mounted? Just curious.

I look forward to seeing how these turn out, as I am in a similar position - I've got the LDC, and would like to try to design some simple surrounds as my first project. Good luck!


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## Bent (May 24, 2006)

Paradigm's ADP series dipole surrounds aren't true di-poles...
they run both midbase drivers and one tweeter in phase, and the rear tweeter 180 degrees out w.r.t. the in phase drivers, this helps it apparent bass response, but allows the out-of-phase diffuse sound from the higher freq. drivers.

( I must be close to qualifying for the RL-p's by now).


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## JCD (Apr 20, 2006)

I only know of one di-pole kit -- Vifa A/V Kit.

I'm not sure how this would specifically match up with the Paradigms you currently have, but If you did like it, you could round out your system with the remaining MTM's or TM's. 
At $380/pr without cabinents, it's not too expensive.

JCD


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## Owen Bartley (Oct 18, 2006)

OK, so it looks like I was wrong about the ADP's, I might have been thinking about the PSB surrounds. I don't have a strong preference for any design, but I think 1 woofer on the front and 2 tweets (in phase) on either side of the speaker. I think they will probably begin life stand or table mounted, and then eventually move to the walls when I get a better room for the HT. 

I guess if I wanted one tweeter run out of phase I could do that, but it seems like it might muck with the sound.

Right now I'm leaning towards one of the designs below.


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## JCD (Apr 20, 2006)

Intuitively, I lean to the slanted side variety. Couldn't tell you why, just a gut thing. Which means the other one is probably better. :dunno: 

Would you be designing the crossover yourself? 

JCD


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## F1 fan (Jul 6, 2006)

A while ago someone on this forum posted this interesting design for a surround speaker. http://www.gr-research.com/kits/av1rs.shtm It is just a 2way with a single tweeter but if placed as intended it will produce a diffuse sound field much like a dipole. I plan on building a pair like these myself soon.Since you are in Canada the GR kit would be pricey,so instead you could build this with a Vifa M13SG 5.5" woofer and D25AG aluminum dome tweeter or similar small 2way kit design.(I have a simple crossover design for this combo if you are interested).The Vifa parts are available from Solen in Montreal so no customs and such to deal with.
Anyway just another option to consider.


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## Owen Bartley (Oct 18, 2006)

Apparently I didn't hit "post" after typing up a reply and closing the tab. 

Thanks guys, JCD, I don't have the understanding/skill experience to do my own crossover at this point.

Fred, I was considering a top mounted tweeter, and a front mounted woofer, I wonder how that would sound. I'm looking into the Vifas too, they're on the list of possibilities. They won't break the bank, but they are getting up there. I just looked at This Dayton kit which doesn't look too bad (excluding their enclosure, and maybe adding a 2nd tweet). I wonder how much it would throw off a design to add a second tweeter that wasn't accounted for.


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## F1 fan (Jul 6, 2006)

OJ, IMO The Dayton kit would be fine for surround duties.
I can't off hand think of a design with a top mounted tweeter and front mounted woofer but that may work ok for surround because the hi frequencies would be somewhat diffuse.I have seen it done the other way with a front mounted tweeter and top mounted woofer.

Adding a second tweeter would require a change in the design of the crossover.

I will send you a PM on special Vifa pricing.


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## Owen Bartley (Oct 18, 2006)

Thanks Fred.

I might attempt a venture into crossover design to see if I can adapt an existing kit/combo to go from a regular 2-way to something like A or B above. Right now I don't really have any idea of the depth involved there, but that's what research is for!


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## Owen Bartley (Oct 18, 2006)

I just came across a site that had a project right along the lines I was thinking, at least it's getting closer. I'd still prefer to have one woofer, but that might not require too much work to the crossover to remove one from his design.


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## Brian Bunge (Apr 21, 2006)

Owen,

I was going to suggest you look at those dipoles to see what you thought of them. Any special reason you want to go with only one woofer?


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## Owen Bartley (Oct 18, 2006)

Not really, Brian. I guess cost and simplicity would be the big ones. I guess the cost increase is minimal, so that's not a big deal. I think if I did a dual woofer and dual tweeter, I'd prefer to do something closer to the Paradigm ADP's with one woof and one tweet facing opposite directions. My Rear Surround placement is going to be terrible, so the more filling the sound is, the better. Would that change in design need a critical reworking of the crossover?


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## Brian Bunge (Apr 21, 2006)

Well, the increase in cost is pretty much negligible since the standard Dayton woofers are pretty inexpensive. While I've never designed a dipole speaker, since you're using these as surrounds I don't think it would make a huge difference. If I were you, I'd email dB to see what he thinks about your changing the woofer orientations. 

Of course, you'd have to make the cabinets a little deeper to accomodate the woofers on the sides. If that's not an issue for you then it couldn't hurt to build them like that and see how they sound. MDF is cheap and you could knock out cabinets like this rather quickly.


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## titch-- (Sep 15, 2006)

Found this one, not really what you looking for though. 

http://www.avsforum.com/avs-vb/showthread.php?t=741282


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## Owen Bartley (Oct 18, 2006)

Thanks Brian, that's what I was hoping to hear.

Titch, the side surrounds on that page are actually almost exactly what I'm looking for, so thanks a ton, I'll be reading more about them in the morning.


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## Owen Bartley (Oct 18, 2006)

Alright, I've been doing my research (instead of working) and I've got a list of potential projects.


GrahamT over at HTG had a very similar project he wanted to do here.
Another similar project from Swithey at AVS here.
The dB 1616 build here.
This Dayton kit from PE which I'd need to add an extra tweeter to here.
The GR Research ones facing upwards here.
the Vifa surrounds here.
And the Modula MTs here.

Having checked out a bunch of other designs, I think I'd still prefer to do something like "A" in my above diagram, since it would do well on a stand or wall mounted, and isn't a big wide mofo. If I could add a second tweeter to the Modula MT's, or even the Dayton kit, or remove one mid from the dB 1616's, I think those would be my top choices. I have no experience with crossovers, so the problem here is I can't just up and redesign that myself.


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## Brian Bunge (Apr 21, 2006)

Well, I really prefer direct radiating surrounds, so I'd probably just build an on-wall Modula MT with the non-BSC crossover. But the design posted at AVS does look interesting. It would be my second choice except I'd want to use the Dayton tweeter as well.


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## Owen Bartley (Oct 18, 2006)

I'm not opposed to direct radiating surrounds, and the Minis work well where they are, but to add the second set of surrounds I'll have a bunch of obstacles in the way and the more of the back of the room I can fill, the better I think it will be. I think in an ideal room I'd probably have all built in direct radiating surrounds, but in the setup I have now I don't think it would do much good.


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## Owen Bartley (Oct 18, 2006)

Tentative decision reached. I think I'm going to go with a modified version of the 1661's, but only use a single woofer. They use inexpensive drivers, and a pretty simple looking crossover, so for a first attempt rear surround they seem perfect for me. 

I've tried to get in touch with Dan, the creator, but haven't heard back from him. My only real concern is what I'd need to change in the crossover to make it work with the single woofer (I'm assuming impedance would be the main issue). I thought before I started ordering I'd ask here and see if any of the crossover designers had any ideas. Oh, obviously I would be changing the enclosure size too, will that have a big impact on the crossover design other than the total volume?

For easy reference I've added a pic of his crossover.


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## Darren (Apr 20, 2006)

I'd give the GR-Research AV1-RS a serious look. I built them and will never go back, they are amazing. The soundstage grew massively and the effects jump around the room now, my old directonals were distracting and eggaerated by comparison. 

I had 5 AV2 MTM's for my system and now have the 3 in front and these AV1-RS speakers in back... I used to be a steadfast supporter of all the same speaker all the way around for perfect voicing but I'm a changed man 

http://www.gr-research.com/kits/av1rs.shtm


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## Owen Bartley (Oct 18, 2006)

You know, I did like the idea of those, and I think I would give them a shot if I had a more ideal room. Here's a rough (not to scale) idea of what I'm working with. I think I still need some direct sound coming at the couches, with a good amount diffused. The one rear surround will be replaced by what I build, followed by a second in the upper left corner when I decide to go for a new amp (my Denon only has 6 channels of amplification, but pre-outs for 7).


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## Owen Bartley (Oct 18, 2006)

After almost giving up on my little project (the consensus from the guys at HTG was that I'd need a total XO redesign), I skipped ahead a few chapters in the Cookbook and came across a pretty good example of what I wanted! It's one of the sample projects in the back of the book, and it uses this woofer and 2 of this tweeter. Price is reasonable, and it looks simple enough to build. I haven't checked for parts availability for the XO, but if everything is available I might just go for it. Any thoughts?


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## Brian Bunge (Apr 21, 2006)

Owen,

The only warning I'll give is that Audax has quit supplying drivers to the DIY market, so eventually parts availability will be zero. Anything that PE, Madisound, etc. is selling is considered "new old stock" and are not being manufactured any more. So if you go with those drivers you might want to consider buying a couple of extras just in case.


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## Owen Bartley (Oct 18, 2006)

Thanks for the heads up Brian. I think I'm just going to make one speaker, since I only have 6.1 right now anyway, and if it lasts a year or so until I can buy a house I'll be happy. At that point I'll probably want a new project and hopefully I'll have a better room to work with. If I have some catastrophic driver failure before then... I guess it just wasn't meant to be.


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## Owen Bartley (Oct 18, 2006)

Needing some crossover advice, so I'm copying my question post from HTG:

I am 90% committed to building this project, but I'm hung up on my crossover parts selection. I've been looking around the PE website and have absolutely no idea which type of caps, resistors, and inductors to choose. I thought the following:

Capacitors: Dayton Metallized Polypropylene 4uF, 8.2uF, 15uF
Resistors: Dayton 10w Non-Inductive 1, 2, 4 ohm
Inductors: Erse 18g Perfect Layer Air Core 0.2mH, 2mH

Does that seem reasonable? I tried to stay away from the cheapest stuff, and the really expensive ones. Keep in mind this isn't for a serious monitor speaker, it's my first attempt at a rear surround.

While I'm at it, what's the general method for hooking everything up to the finished crossover? Should I get some kind of terminals to go on the boards, or can I just run a wire from the input cup to the first component? Should I be using solid wire to connect from XO to XO and from the XO to the speakers, or is stranded (speaker) wire more suitable?

There is a lot more going on behind the scenes than I thought!


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## F1 fan (Jul 6, 2006)

What project are you building?The Audax in LDCB?

Those parts will be just fine,but you should pay attention to the DCR of the coils if the designer has specified them.

I hot glue or silicone the xo parts to a piece of masonite then wire the components point to point .


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## Owen Bartley (Oct 18, 2006)

Thanks Fred. The one I'm building is in post 23 on the first page, sorry, it doesn't really stand out. It's the Audax dipolar surround project from the LDC (6th ed). I don't have the book with me now, but I don't think he specified much about the parts, unless I missed it in the beginning of the chapter. In post 23 there's a diagram of the project and the crossover. Have you built those ones? Any advice? I'm starting to get excited, since I've been jonesing for a project for a while now.


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## F1 fan (Jul 6, 2006)

Owen,the DC resistances of the coils you linked to have about the same value as Dickason specifies so they will be fine to use.

No I have not built those myself but that design should do the job of a surround speaker quite nicely.

The only advice I would give is to be sure that the crossover is wired correctly and that the drivers are connected with the proper polarity.

Good luck on your project and take some pics to show us.


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## Owen Bartley (Oct 18, 2006)

Awesome, thanks again Fred. I'm sure I'll have another post with more specific crossover hookup questions, but this is enough to at least place the order. And I'll make sure to take lots of pics of the process and the end result.


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