[Saurav]

I'm thinking of trying to build an open baffle speaker. I'd like to re-use my Fountek JP3.0 tweeters, and probably try a Visaton B200 under that, XO points at say 200Hz and 4kHz (or higher, depending on how that works out), driven by a tube amp. Below that will be an active XO and an SS amp. So I don't need the woofer to be the same sensitivity as the rest of the drivers. Hopefully that should increase my options a little.

I don't want to use a 15" driver mostly for visual reasons; that'll look pretty overpowering in my living room. Ideally, I'd like to stick with a single 12" driver per side, hopefully in a 15"-20" wide baffle, maybe with wings / a shallow U-frame. Budget - not too much more than $100 / driver. It'll be great if it goes down to 40Hz in-room, but I would be OK with 70-80Hz too, I can bring in a monopole sub under that.

I have the Xlbaffle spreadsheet, and yesterday I installed MathCAD Explorer to play around with MJK's worksheets. I've looked at the Eminence Alpha/Beta 12s, mostly because MJK used the Alpha 15 and it seems to be popular, but the 12s seem like fairly different drivers. The 10" Hawthorne Audio Augie is interesting too, but I didn't find any T/S parameters for it. Other than that, I'm really not sure what to look at. So, any pointers or suggestions would be most helpful.

Thanks in advance,
Saurav

[gitarretyp]

I'd look at the peerless sls 830669, the shiva-x or dpl-10 offered by diycable, and dayton rss315.

The T/S for the Augie 10 are:

Qes 1.16
Qms 1.48
Qts 0.65
Fs 33Hz
Re 5.69
Sd 0.0345 m^2
Vas 150L
xmax 7.2mm
Pe 150

[Saurav]

Thanks. I was thinking of the Shiva as a candidate for the monopole sub Right now I have a 1259 in a sealed cabinet. I didn't realize that some of these 'subwoofer' drivers could be used up to 200Hz.

[gitarretyp]

Sure, most well engineered sub drivers should be fine to 200Hz with a > 2nd order crossover --4th or more would probably be best. I wouldn't go too much higher than that, but 200Hz shouldn't be a problem.

[Rudolf]

I recommend the Peerless sls 830669. Generous x max, and this driver is very well vented in all parts - no chuffing at all or any other noise.
One caution, that applies for all "hifi"-drivers in contrast to most Pa drivers with accordeon surround: When over-driven, the sls voice coil former will slam against its back plate without warning, while most PA drivers are limited (and protected) by rising suspension stiffness (non linearity).

[Saurav]

Where can I buy that in the US? Madisound shows it as out of stock, and a quick Google search didn't turn up any others.

[Rudolf]

Where can I buy that in the US? Madisound shows it as out of stock, and a quick Google search didn't turn up any others.

Sorry, I didn´t check for its availability in the US. It´s still in stock in Germany, but that won´t help you of course.

[ttan98]

If I remember correctly Peerless sls 830669, has low spl, other alternatives with high spl are

Lambda TD12H 12" from AE
Ciare 12.00NdW1 12” from assistance audio,

both units have high spl > 92db,

go to this site for more info,

http://www.htguide.com/forum/showthread.php4?t=29988.

I am in the hunt as well.

[gitarretyp]

If I remember correctly Peerless sls 830669, has low spl, other alternatives with high spl are

Lambda TD12H 12" from AE
Ciare 12.00NdW1 12” from assistance audio,

both units have high spl > 92db,

Those two drivers would be great for a sealed or ported design, but their qts/qes are a little on the low side for OB. Especially that ciare. It doesn't have much xmax, a high fs, and low qts.

[Saurav]

I'm keeping an eye on that HTGuide thread, I've posted in it too

The Lambda's are way outside my budget, and the Ciare's are getting up there as well.

I currently have an Audax PR170M0 (on an OB) and a Fountek JP3.0, with a Peerless 850146 (discontinued 10" woofer) in a sealed cabinet. I want to try a dipole woofer, that's the point of this exercise. The Audax/Fountek combination works well, but they're both a little stretched to get to the 4.5kHz XO point. I was thinking of using the B200 as a midrange, which would then get me to ~200Hz for the woofer XO (the PR170M0 won't go that low, only 0.5mm Xmax).

But a different option is to keep the Audax, and get a different tweeter that can cross lower. To keep the 95dB+ sensitivity (I drive these with a 2A3 SET) I think I'll need a good compression driver (I've tried some cheap Eminence and Selenium CDs and didn't like them). BMS & B&C make CD tweeters that seem to be popular, and could handle a ~2kHz XO. But if I keep the PR170M0, that means my woofer now needs to go up to 350/400. And I'm not quite sure what that implies... a U/H frame is probably out, since that'll be up in the cavity resonance region, I think.

[navin]

I currently have an Audax PR170M0 (on an OB) and a Fountek JP3.0

But if I keep the PR170M0, that means my woofer now needs to go up to 350/400. And I'm not quite sure what that implies... a U/H frame is probably out, since that'll be up in the cavity resonance region, I think.

12" OB might not be adequate unless supplemented with a monopole sub.

I would look for the DPL-12 from Exodus/Audire. I heard Kevin Kaskins has it ready. Stick this into a shallow U frame (about 4-6" deep) and give it's high Qts you should be ok till about 40-50hz. Your monopole will then only have to operate below 40Hz (if you need that last octave and/or high SPLs).

Mate this to the B200 (the B200 needs a bit of XO help to smoothen out it's response) and Fountek. BTW is not the Fountek rated at 95db/1W. I believe the B200 will mate ok with that.

see http://sho.mystarband.net/

[ttan98]

Saurav,

I hope this maybe of some help to you, I am just writing from my experience, currently I am rumning my open baffle in a open baffle configuration, TWW. the 2 woofers are 12" with Fs=37hz and qts=0.56. I still need to build a U-frame to get the freq. response down to 40-45Hz.

I believe you want to get the freq to go down to that region you need low Fs as well as high Qts>=0.7, if you cannot get qts >=0.7  then you need U or H frame. I also believe you want open baffle bass then you need 2 woofers not one connected in parallel.That will move enough air to give you sufficient presence, just like Emerald physics, CS2, 2*15" woofers. It is hard to find 12" woofer with fs=40 or lower and high qts. Only some 15" will fall into that category. I am in the same dilemma.

If you want to build with 1*12" woofer than I think monopole, vented is the way, like J. Bagley's open baffle. I found a 12" woofer build with 80-90l box will give you around 40hz. The brand is Beyma, 12br60($125), go to HTguide for details.

Cheers.

[Saurav]

I will have a sub, and I don't mind crossing at 70-80Hz if I need to.

I'm undecided about what to do with the MT portion. The B200 seems well liked, but everyone who's measured it talks about the rising FR. I've considered keeping my PR170M0 (which I like), and maybe getting a compression tweeter to lower that XO point, or just sticking with the same PR170M0/JP3.0 combination I have now (which isn't ideal, but again, it's a popular combination, and I like the way it sounds). But that means I need the woofers to go up to about 4-500Hz now, and that kinda restricts my choices.

I'm currently leaning towards a pair of Dayton RS270's, they look clean up to 500Hz and higher. The high XO also mostly rules out U and H frames, so I'm modeling these on flat baffles to see what I get.

I found some old FR graphs of the original DPL-12, and I'm not sure I can use it to 500Hz. If I can, that would be a great option. I know Kevin has a DPL-10. If I run into him at VSAC in a couple of weeks, I might pick his brains on this.

[Saurav]

If you want to build with 1*12" woofer than I think monopole, vented is the way, like J. Bagley's open baffle.

My current speakers have a Peerless 850146 in a sealed 60L cabinet handling the bass. The whole point of this exercise is to try dipole woofers And I agree, I'm leaning towards a pair of 10s as my best option. A 15" woofer will look really big in my room, otherwise I'd probably be looking at those.

[ttan98]

You may want to ask gitarretyp, he uses 4*M165X(7" woofer), about $44 each with Fs=40 and Qts about 0.4. He uses open U-frame he may have some suggestions to get freq low.

[Saurav]

Yes, I've read through his thread and looked at the pictures a few times. 4 x 7" or 8" woofers would be another option, and it's in the same price range.

What woofers do you have in your speakers? And what's the top end of their frequency range?

[gitarretyp]

You may want to ask gitarretyp, he uses 4*M165X(7" woofer), about $44 each with Fs=40 and Qts about 0.4. He uses open U-frame he may have some suggestions to get freq low.

They don't reach very low on their own, and i high pass them LR4 at 75Hz. Acoustically, the roll-off is ~4th order 60Hz with no filter in my arrangement. They work very well in this application, and have nearly identical swept volume as the RS270. If you're looking at the 2 x 10 route, you should look at the Peerless SLS 830668. When i was choosing, it was between the Peerless, Dayton, and the 4 x M165X i have now. They model very similarly in xlbaffle. All of these drivers have been used successfully in OB projects posted in various places, so it will come down to personal preferences. I chose the 165s due to their lower total Mms, flexibility in impedance wiring, and i'm familiar with Danny's drivers and trust using them for a high'ish crossover --mine's only LR4 250Hz, but this is something you should consider.

[ttan98]

You see even though my woofer looks from the spec(manu. spec) point of view(I never measure them myself), I bought them quite cheap, it does the job to the bare minimun, it lacks
1. dynamics
2. low power handling
3. low xmax(I think)

but they are cheap believe it US$17 each.

I am looking like you for a replacement. As they are, the sound is quite good(freq. can get down to 40-45Hz), if I replace them with better woofer the sound quality would improve dramatically.

[JoshK]

Lambda 12TDX...

[Saurav]

Lambda 12TDX...

I wish That's way outside my budget for this project.