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Subwoofer with OB speakers

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I am taking my first steps what comes to DIY speaker design :nerves:. There is a lot of great info on this forum, so many thanks for all.

Has anyone built/heard Infinite Baffle subwoofer systems? I could have understood this all wrong but would it be possible to get to lower on the frequency range with this subwoofer type? I am planning/dreaming to built a clean and punchy subwoofer system that would have a great synergy with my Bastanis Atlas open baffle speakers. This would meant that the sub would have to cover the frequencies down from 100Hz. What I am wondering now that would IB subwoofer combined to tapered baffle subwoofer give me what I am after?

My listening room will be 4 meters by 5 meters in a 1920's timber frame house with suspended floors.

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interesting thread Juha, im getting no where with my open baffle speakers in the bass, i have tried several drivers and now have a pro amp that punches out 400 watts and still cant get the bass i need or want. i am about to give up with the OB thing as its taking up a lot of time and expense to get right. i noticed you upgraded with another pair of drivers and you still need more bass. I think a sub is the only way to get deep bass but it does go against the whole OB thing. steve in the diy section is have no joy with bass either so its not an easy one from what i see, all the suppliers of OB ( bastanis, hawthorne et al ) all state great bass but its just not true. awe well i.ll plug on a bit more but am losing the interest. good luck

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Depends what you mean by bass. If you want 20hz, forget open baffle for it. however, ob with a high qts driver will give you weight and speed, just not huge depth.

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adam.

im not getting deep bass and im not wanting 20Hz. my LV's only go to 40 and this is very deep and enough for me. I have a high Qt driver ( 15" alpha) i have no weight either but im going to keep trying. the addition of the pro amp was a big disapointment it made the bass sound very hummy if that is a word but its how it sounded. not nice at all.

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It's all about the wavelength and cancelation between the front and rear waves. The longer the path from the rear to the front the lower you bass will go. The roll off in a symmetrical baffle will be 6db per octave by having different lengths on each side you can reduce this by having 4 separate roll off frequencies.

Given enough size and a low enough resonant frequency you should be able to go low.

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I am surprised at the bass quality from an old Wharfedale SFB 3 I am rebuilding,It may not go particularly deep but it doesn't sound bass light.Mind you the baffle size isn't small (3 foot wide) and 12 inch and a 10 inch driver in parallel gives a good radiating area ,maybe that's why they lost popularity when stereo appeared.

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What shape cabinet do you have? I have 15 alphas too, and I get down to 40hz with my folded baffle.

Good point Adam,

i have them in a di pole box but am going back to folded as i liked that better with the beta drivers, the Alphas should go lower than the Beta's given the higher Qt's. Might try a H frame cabinet as well.

What are the dims of your folded Adam as this has a big effect from what i read. the last ones i made ( dumped them as the damp got at them in the shead) where 18" square front panel and 12" sides and top with open rear. No maths behind these dims just suck it and see/hear sort of thing.

cheers

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interesting thread Juha, im getting no where with my open baffle speakers in the bass, i have tried several drivers and now have a pro amp that punches out 400 watts and still cant get the bass i need or want. i am about to give up with the OB thing as its taking up a lot of time and expense to get right. i noticed you upgraded with another pair of drivers and you still need more bass. I think a sub is the only way to get deep bass but it does go against the whole OB thing. steve in the diy section is have no joy with bass either so its not an easy one from what i see, all the suppliers of OB ( bastanis, hawthorne et al ) all state great bass but its just not true. awe well i.ll plug on a bit more but am losing the interest. good luck

Ron's right, I've been messing about for the past week or so now - and luckily - am at the stage where I am extremely pleased, actually bloody surprised, with the P17s, incredible detail and soundstaging, clean, clear, effortless, light and airy - really great :party:

yes, bass is an issue, a lot of my woes have been overcome, initially, there was next to nowt below 100Hz I guess. Driver is well run in now and I have tuneful and tight bass, albeit still lighter than I would like. I am using a bloody great Eminence Omega 18" pro driver(97 dbw, 8Ohm, QTS 0.31) and it certainly doesn't live up to it's looks! Positioning has played a big part, also, I am now using two rather crap AV subs below 40 Hz and that has helped, as has various levels of wadding in the back - don't want to move away from the OB principle but with drivers this big the box is never going to be as large as it should be, 4 pillows and a 50mm acoustic foam panel on the back and I'm there! To be honest, I don't think I could go back to a box at the mo, these things are very horn like in their transparency and speed - I'm not nervous of using subs either if it's done properly (after all there was 8Ks worth attached to my Avantgarde Duos....)

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looks great Steve, bloody inpressive to say the least. I am still playing around with mine and have gone from a simple 250hz X=over to no crossover at all bar a simple resistor and cap at the tweeter to protect it. not sure what i prefere to be honest. Im going to remake the baffle and a new U box for the alpha bass driver. I think i will just get all my connections on crocodile clips and change around to see what happens and what i prefere. Its all very hit and miss isnt it? the mid is superb and very addictive but the bass is a long way off at the mo for me.

What x over points have you got on your speakers?

good luck

Ron

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Actually I think I read the OP wrong - Juha - you're not talking about building a full range OB speaker but an OB SUBWOOFER on it's own right?. If so, I'd respectfully suggest that's the wrong tree to be barking up... I know that Lukasz Fikus, Mr Open Baffle, uses his bass units in enormous baffles, bookcases and such, that may work, but otherwise, you'll get a fast mid bass driver in an open backed box as best...

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What are the dims of your folded Adam as this has a big effect from what i read. the last ones i made ( dumped them as the damp got at them in the shead) where 18" square front panel and 12" sides and top with open rear. No maths behind these dims just suck it and see/hear sort of thing.

It is a bit random, I think. Mine are 15" Alphas in a front baffle about 50cm wide with a box (open at the back) about the same depth, so it will simulate a baffle about 1.5m wide.

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cheers Adam,

will get a play at these tomorrow and see if i can get a better sound, Have the 12" patriots to try as well so may well get better when i take the cheap chinese ones out

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Hi Steve.

Let me clarify myself :D.

I am really really happy what my four 12" Bastanis wideband drivers with pair of Gemini tweeters are doing on my OB set up. This configuration is giving me extremely transparent sound which will be very very close to Avatgarde Duos. I know that is a bold statement, but they are really that good :love:. This set up is giving me everything I need above the 100Hz. I have no plans changing them. Well saying that wideband drivers will be upgraded to Bastanis Crystal sometime in the future, but that is not the issue here.

Reason why I am looking to change my subwoofer system is that I need/want more slam, body and structure than 15" sealed woofers are currently giving me. Could be that I am chasing my tail here, but cannot help myself :doh:. I have been doing a lot of reading what comes to different ways of getting there and at the moment I am sure that I will built a pair of 20Hz-40Hz tapped horns and combine these to another pair of smaller tapped horns from 40Hz-100Hz. This should give me what I am after, in principle. I have bought the 6.5" drivers for the smaller tapped horns and just need to buy the 15" Eminence drivers for the bigger tapped horns. Could be that this all is a overkill on my small room, but I need to try and hear it by myself.

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Hi Ron.

I noticed a big difference when I installed a second pair of Bastanis wideband drivers to by open baffles. The sound became much more authorative and filled the whole room without an effort, and this is with 300B SET amp. My Diavolo is more than capable of driving 100 db sensitive Bastanis. Robert Bastanis has designed his Mandala line speakers so that frequencies above the 100Hz are done by the wideband drivers with yourmain amp and below this frequency you need a pair of plate amps to drive the subwoofers of your choise. In my case they are 15" sealed woofers in a box driven by a pair of XTZ SUB 1 amps. You can also have 18" woofers in a dibole set up. It is this subwoofer set up I want to change, not the OB :D.

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