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Old 23rd March 2006, 07:47 AM   #1
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Default open baffle

if anyone knows, it would be those experts here. so here goes.

anyone have a good open baffle design that do not totally lack bass? (some bass is fine for me, I don't need feel it in my chest)

is the choice of driver for open baffle design so critical?
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Old 23rd March 2006, 11:05 AM   #2
Rudolf is offline Rudolf  Germany
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I would suggest this principle:

http://www.bd-design.nl/contents/en-uk/d84.html

http://www.jamo.com/Default.aspx?ID=...roductID=17723

Peerless SLS 15 (or SLS 12 maybe) for woofers should do pretty well. Fullrange driver above to your taste.
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Old 23rd March 2006, 11:57 AM   #3
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I'm running a pair of Silver Iris coaxials in a (temporary) large open baffle and the bass is excellent - deep and clean. I intend to do a lot of experimenting with the baffle design before finalizing it, so I just bought some prefab 2' x 4' mdf sheets for the fronts and 1' by 4' sheets for wings on the side. I threw the sheets together, plopped the drivers in 24" from the floor and powered 'em up.

My long-range plan is to do something like the BassZilla, but dipole in the bass as well.

So, it is very possible. The challenge is minimizing the baffle to be acceptable with respect to waf.

It helps to have a driver with high Qts (> 0.4). The Qts for the Silver Iris is around 1.3, I recall. The alternative is applying EQ to boost the bass.

I'd suggest doing searches using the keywords 'OB' and dipole (in addition to open baffle). Here in the full range forum, there is a fair amount of OB discussion regarding the Visaton B200 driver.

If you want a more or less finalized design, there is, of course, the Orion. If you do not want the requirement of 6 channels of power, another tested design from a respected designer is the Arvo Part.

If you need links for any of these designs or drivers let me know.

Good luck.

Paul Ebert
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Old 23rd March 2006, 02:33 PM   #4
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As stated above, the Visiton B200 seems to be the hot item. I've been emailing with DMason about that very thing. If you want just one driver, that's probably it. If you can do more than that, the B200 with one of the Supravox woofers is supposed to be very nice. Also, you could try one of the Knight woofers, they're inexpensive and very nice as well.

The B200 will provide decent bass on the right sized baffle. And more if you place it a little lower on the baffle and angle it slightly upward.

If you really want a nice OB system, check out the BD Designs Quasar, or the Basszilla.
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Old 24th March 2006, 12:20 AM   #5
dmason is offline dmason  United States
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I think more and more that a WAF positive OB system is pretty doable, using acoustics to your advantage.

Mounting a 15 inch woofer with low Fs and high Xmax low in the baffle to take advantage of floor lift, forcing the driver to roll off acoustically upward and pretty well done by ~250-280Hz.

A 16 inch baffle with 5.5 inch sides theoretically should provide very acceptable and inclusive, forward-wavelaunch of ~300Hz, depending on the driver. ie: The higher the Q, the better suited. Anything over .4 works very, very well in this situation.

Powering the lower driver with even a cheapo sand amp works fine, and make sure to budget for EQ, contouring the bass, using a "digital crowbar" to wring the most bass response out of the bass driver.

If you have gone to this extent, you should think about a sweet couple of SET watts to power the treble driver, which is ideally XO'd to roll in over 200-250Hz which will include the lower end of the critical midrange. Freeing a flea amp of the lower frequencies <100Hz will add ~40% more useable power to the treble signal.

The B200 works a treat, and is design-specific for open baffle, for a fact. That it works in other BIG loads like the 175 sealed box is a function of the high Q=.7 rather than anything else. Powered by SET, and shelved under 200Hz it becomes a real hologram projector. The Hemp cone sounds very nice on OB as well. THese drivers are near identical in the critical midband.

The best bass driver I have seen overall is the inexpensive $119 Dayton 15 "Pro Driver" IB-385-15 designed for Infinite Baffle at www.partsexpress.com This is ALL you need for a single 15 bass driver. Another real pro audio driver I like is the Ciare 18.00Nd W, a big 18 with Fs-29Hz, great Xmax, first class build, and surprisingly good price of $200. However, my final conclusion is that pro audio bass drivers are less than ideal for OB, most have Q just too low to make that choice, and because of requirements, one doesnt need to spend much at all for good success, two very good reasons. Try a cheap-o 15 with the right ingredients and it likely will be "good enough."

This whole thing is more a Rubik's Cube than a science in my experience, but for a condo-friendly OB set up, this is exactly the direction I am heading. 40 X 16 X 5.5 with rear baffle, and cutouts of equal diameter to the drivers. One inch more, for the treble driver. A Kondo-KwaZar.
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Old 24th March 2006, 01:18 AM   #6
Dumbass is offline Dumbass  British Antarctic Territory
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Quote:
Originally posted by dickylickie
is the choice of driver for open baffle design so critical?
A lot of the vintage full-range drivers that were used for things like radio consoles and such are great candidates for open baffle.

Here is a list of drivers:
http://members.myactv.net/~je2a3/open.htm

You need to have Qts above .5 or so for decent low end in open baffle.

I have this conjecture (not sure why) that full-range beaming is less obvious on large open baffle. Why?
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Old 24th March 2006, 08:18 AM   #7
Nanook is offline Nanook  Canada
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Default the caped crusader is back...

hm...open baffles=JE Labs "design"

ad nauseaum... I built these, with cheap, free Oxfords, I've docu,ented em here I think someplace. Do a search for Open Baffles, lots will com up on diyaudio.

as for any wondering about bass, a new aquaintance has listened to them and likes em... He's got Basszilla's (AER drivers, soooo nice....), 2 watt flea power, Vifa or Peerless subs, an active xover, and some amp modules (unsure what he is actually using), etc, etc, nice Kuzma tt (the Brass log, a Stabi/Kuza? ). He likes my poorly built ,super cheap, they're so ugly I'm not allowed to have em upstairs in the living room OBs. Matter of fact, he's gonna try a pair with one of the sets of fullrangers he has at home (Lowthers I think). I was driving them with an old Realistic STA72 (?, 12 watt receiver from early 70'), and my PS1 as a cdplayer. That system is in the 70-100 range

One little secret .If you're gonna try an OB, build the "JE Labs" ones, but don't change the mounting position of the driver.Do not use the small "shelf" piece near the top of the baffle. Go full width and attach to the side "legs". Also put a full width brace at the back , attached to both legsabout 6" wide and attached perhaps an inch up on each leg.

another thread...OB woofer suggestions..Nanook

Everyone who has heard them loves them. Thorsten (?), here on diyaudio apparently built some and is marketing them , if I remember correctly
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Old 25th March 2006, 03:49 PM   #8
2litre is offline 2litre  United States
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I'll have to agree with Nanook on all points. Having finally built these OB's (4th project), I'd have to say that this should be the first project for anyone looking at DIY OB.

Last weekend I built the "JE Labs" OB. Cabinet dimensions are spot on but I used a different combo of drivers (liked the Wharfedale pic), some FR125S' and some RS225's. The FR125S run full range. I'm still experimenting with the roll off points (bi-wired) on the RS225s, right now at 91Hz.

http://i39.photobucket.com/albums/e1...e/DSCF0485.jpg

My room is really small and the FR's, now in a good sized baffle, do a fine job in thier own right. With power to the RS's the effect is very subtle, like flipping the loudness switch on the reciever. I have no idea as to SPL. If I want to go loud I just pick a bass heavy track, adjust volume to the excursion of the FR's and sit back and enjoy. But once I get that loud the wife usually has to tap my shoulder to get my attention. Loud enough.

R/

Jim
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Old 19th April 2006, 07:38 AM   #9
Sarchi is offline Sarchi  Canada
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Maybe this would be a good thread to piggyback/hijack onto....

I have a VERY small room, it's 9x12 but one wall is floor to ceiling LP's so effectively 9 x 11. I'm a FR devotee having owned Lowthers and now Fostex/Omegas. I have a decent powered sub, bass is not an issue, though I'd want FR's that could go down to 100Hz or so.

I'm interested in the JE Labs OB (btw, I actually heard Ding's 604-8G OB's in Manila 5 yrs ago.. fantastic on rock music!), but I'm wondering if a scaled down version would be feasibel? Advisable? Ideally around 20" wide, height could be up to 36" or higher...or lower. Could this work? If the baffles were full width it would really hinder access to my records.

A pic: http://www.triumph675.net/homeoffice.JPG (my sub is now in the middle next to where you see the Barbiemobile)

I have no speaker building experience at all. What FR drivers could be used? Keeping cost down..no Lowthers for me right now.
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Old 19th April 2006, 01:14 PM   #10
Nanook is offline Nanook  Canada
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Default two things come to mind...

what's behind your listening chair?

could the records be moved?

as for a baffle, perhaps something using a decent fullranger such as the much heralded FR125S? Is sensitivity an issue? Do you use active Xover or a passive one (or one "included " with a powered sub?)
If too much trouble, I'd suggest a transmissioin line with the same FR125S driver, it would be small enough, and could be made to fit into your 20"X36" design criterion and easily extend cleanly to 186Hz assuming full wavelength, or 46Hz, assuming 1/4 wavelength. I am no TL epert, others here are certainly technically more proficient, but it seems like eithe way something could be done. If wanting an OB, I'd also suggest making a "U" baffle with a top, similar to the Prometheus. Maybe Dave could chime in if he sees the thread.
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