Open Baffle: long-term S.Q., what's your experience?

[KT]

I've been so intrigued by the experiences many of you have had with open baffle speaker designs. The qualities attributed to them seem to be right up my alley in terms of sonic priorities.

I'm wondering, however, if any of you have been satisfied enough, despite the quirks in top and bottom end frequency response, to keep them as your long-term speaker solution?

I'm considering building a set with either the FE-103a Coral holey basket drivers, the older CSS FR-125S, or a pair of the Altec 755E.

I've had a pair of Lowther DX-3 in an admittedly sub-optimal enclosure, and while I found the sound captivating in many ways, I always went back to my Klipsch speakers due to a lack of bass authority with the Lowthers. I wonder if OB is similar in that regard.

How did the OB design pan out for you?

Thanks,
KT

[marec]

I've made a few OBs now, ranging from single 10" full rangers to 2 x 15As + an EX3. Sizes have ranged from 5' x 4' to my current MJK 38" x 20" with a single 15A and a 108EZ using a passive crossover. This is now my main speaker, with a pair of Lowther Delphics languishing in the corners.
I don't listen all that loud, and in the relative near field, but I think these domestically acceptable loudspeakers give me more pleasure than any other I've ever owned (and they cost next to nothing in either materials or skills!).

[MJK]

Originally posted by KT
I'm wondering, however, if any of you have been satisfied enough, despite the quirks in top and bottom end frequency response, to keep them as your long-term speaker solution?

I am not sure what quirks you are refering to in the OB response. My last two dipole speakers have had more bass output then my previous single driver speakers. Bass output is not a problem if the OB is done right with the correct drivers.

I'm considering building a set with either the FE-103a Coral holey basket drivers, the older CSS FR-125S, or a pair of the Altec 755E.

I've had a pair of Lowther DX-3 in an admittedly sub-optimal enclosure, and while I found the sound captivating in many ways, I always went back to my Klipsch speakers due to a lack of bass authority with the Lowthers. I wonder if OB is similar in that regard.

Why not stick with the Lowthers and design an OB system that works with the DX3? It would be great.

I would not waste time with the three older drivers you are considering, either use the Lowthers or buy a new ~4" full range driver and build the OB or dipole system using a more modern driver.

How did the OB design pan out for you?

An open baffle system using a full range driver crossed over low to a pro woofer(s) solves a lot of problems that exist in a completely single driver system. The ease of design and construction make it a simple concept to get right. If you think the design through it is hard to screw up compared to a more complicated enclosure/boxed design.

[norman bates]

My open baffle w3-871s (needed bass support) was a source of many, many pleasurable hours of low volume listening.

Judging the off axis response and the graphs in stereophile a few months back on the double 12" jamo, the dipole dip will not show up 8-10' away from a dipole in a room.

If you are a full range driver fan, then you are in for a world of headaches if you want higher volumes. Active crossovers sound horrible (especially pa and digital stuff).

I ran mine wide open with an f-mod to some woofers.
Forget impressing somone with slam and volume, that's not what lowthers are about.

I agree with going for the lowthers. But you went back to klipsch for the bass.

MJK is totally right that open baffles need bass support.
Hey an 8" can only move so much air.
Check out mjks design of dual 15" eminence.

But maybe you should build a cheap thing with a good pair of full range drivers you like and already have.

Remember to have the driver offset from the 3 edges for best sound (I.e. 24" wide baffle having the driver 9.2" from left, 14.8" from thr right, and 12" from the top). 1 : 1.31 : 1.618 ratio. But 9.2" from the edge gives an Feq hump at 280hz, then its response drops like a rock. Don't forget that a driver on an open baffle rolls like an infinite baffle. It hits its mass corner (Fs/qts) then rolls off............. Qts .2 lowther with fs of 50hz, the driver will roll off below 250hz regardless if the baffle is 8' wide.

The larger baffle you get, the lower you go (unequalized and not including mass corner), but the less back wall bounce (assuming baffle is 5' from the back wall so you get best sound). Some say huge open baffles have a black hole in the middle (no 10ms low level wall bounce fill).

Or make a foam box to surround the back of the driver and place the open baffle much closer to the front wall. You get clean mids that an OB give you and you can have it a foot from the wall.

Norman

[cuibono]

Originally posted by KT

I'm wondering, however, if any of you have been satisfied enough, despite the quirks in top and bottom end frequency response, to keep them as your long-term speaker solution?

How did the OB design pan out for you?

Thanks,
KT

It seems people who go 'OB' don't go back.

I think any 'quirks in the top and bottom' have to do with the drivers used, not OB itself.


"try it, you'll like it"

[dzzmiller]

One problem with a passive crossover in a system like this is that the calculated design may be far from what sounds best.

As far as active:
Scenario 1 : A $250 digital crossover is plunked down in the analog signal. The device must encode and then later decode the signal. It has 3 A/D converters and 6 D/A converters (for $250). It can't be surprising there's a loss in quality.

Scenario 2: The Crossover as DAC. $800 - $2000. The crossover is the last stop in the digital chain. You make sure the computer/transport data rate do not require a conversion. The A/D converter isn't used. This sounds a lot better. Because it's not just a crossover, It's a DAC, EQ, and xover.

Most people wouldn't bother with an active on a two way system. But a passive on this system is unlikely to be near optimal.

As far as the design, it's worth noting how Linkwitz got a pretty high WAF for the Orion. He used 2 10" high xmax stacked woofers to move air. He integrated the top and bottom. Most O.B. designs low WAF is only "bettered" by bass horns.

[MJK]

I pretty much disagree with everything you have said.

A passive crossover design can work great on a two way OB system, there are even some advantages to using a passive crossover. Designing one is not that hard.

I have also found that a pro digital crossover can sound just fine. I have not had any problems or noticed any degradation with my active digital crossover. I think using the balanced connectors and not trying to convert from RCA jacks to a balanced connector helps. The pro digital crossover allows you to try all different combinations of crossover frequencies, slopes, and levels of boost to dial in the best response. Knowing what works, the next step to an equivalent passive crossover is not that complex.

[hitsware]

>Some say huge open baffles have a black hole in the middle

I say that.
A workaround is to run both channels on 1 baffle in a corner

[dzzmiller]

Originally posted by MJK


I pretty much disagree with everything you have said.

A passive crossover design can work great on a two way OB system, there are even some advantages to using a passive crossover. Designing one is not that hard.

I have also found that a pro digital crossover can sound just fine. I have not had any problems or noticed any degradation with my active digital crossover. I think using the balanced connectors and not trying to convert from RCA jacks to a balanced connector helps. The pro digital crossover allows you to try all different combinations of crossover frequencies, slopes, and levels of boost to dial in the best response. Knowing what works, the next step to an equivalent passive crossover is not that complex.

Maybe I wasn't clear. I think the pro crossovers are fine. But if you put an inexpensive Behringer after a good DAC it's not going to sound as good as it would with the DAC and a passive crossover.

The opinions of the Behringer are so varied it seems to me some people must be placing it after the DAC.

I have a modified Behringer and it's fine. I've also heard a friends dbx, and that was good too. I would have gone with the dbx to avoid the Behringer mods, but it's only 24/48. I've purchased a fair amount of 24/96 classical music.

Your final point about using the active to find out how you want to build a passive is good.

I've only built a simple passive xover. I much rather play with the sound on an active.

I'll add that when a passive is used and sounds good, the project is usually finished. The potential of other possible setups is not explored. I think the math is only a rough model that will usually be O.K.

[Cal Weldon]

My experience so far is limited to OB mids as I can't quite wrap my head around the bass idea.

OB mids is one feature I will try and incorporate in future builds.