[jarcher]

So I notice that a lot of pre-90's speakers had wide front baffles - I just figured it was the style, or maybe it was a cheaper way to get more volume w/ less depth to the enclosure.  I'm starting to these this style come back more often - and for the first time in Dec 12 Stereophile's review of the Devore Orangutan some words were spent unclearly about possible advantages. 

Narrow baffles always made some sense to me : i.e. reduce reflections, supposed better imaging, etc.

What would be advantages of wide baffles?

[stereocilia]

A speaker designer might correct me, but I think the main advantage is more bass.  With a wider baffle, the frequency at which the speaker transitions from a directional beam at high frequencies to an omni-directional sphere at low frequencies goes down.   So, more of the bass is pointed forward instead of spilling out in all directions from the speaker.

[Letitroll98]

The Devore Orangutan's were my best at show speaker for this years Capfest.  Not the most impressive or bombastic, but stunning imaging with a remarkably beautiful tone.  If I remember correctly, the wide baffle was to simulate an infinite baffle as closely as possible in a small speaker.

[navin]

So I notice that a lot of pre-90's speakers had wide front baffles - I just figured it was the style, or maybe it was a cheaper way to get more volume w/ less depth to the enclosure. ...What would be advantages of wide baffles?

As far as frequency response goes, the width of the baffle can be compensated for by a simple L-R combination for the baffle step.

Maybe baffles were wider then because small woofers (sub 8") that could go low were not common (the early 90s saw some developements in management of the magnetic gap, material technology, and the common availability of NdFeB magnets and this allowed small 7" woofers to go as low as 20hz). Just like it common today to see a heavy cone 10" woofer mated to 2 passive's producing 20hz at 80db/1w/1m.

As far as imaging goes I dont beleive there is a significant difference between a 20cm baffle and a 24cm baffle. In fact one of the speakers that had great imaging had a 10" woofer and had it's mid and tweeter place side by side. The Snell Type C (C/i)
http://www.oaktreevintage.com/web_photos/Stereo_Speakers/Snell_Type_C_stereo_Speakers_Web.jpg

[jarcher]

So I decided to stop being lazy & try to look it up on wikipedia.  Seems that baffles may haven been made wider / larger as a way to minimize driver back-wave interference which could cause attenuation of lower frequencies (?)  Perhaps later designs used enclosure & filling materials & techniques to reduce this potential interference, allowing for the more effective use of smaller or narrower enclosures (?).  That's my best guess if I'm reading the wiki correctly.

The Stereophile review of the Orangutan seemed to suggest some people liked the way a properly designed wide front baffle could affect the sound / tonality?  Guess I should be asking the open baffle circle people as well.......

[rjbond3rd]

Hi jarcher,

That's getting very close!  The exterior and interior of the box are separate issues.

Outside: when the baffle is large compared to the wavelength (e.g., 1000Hz), all the energy moves forward.  The baffle is wide relative to the frequency.  But something else happens when the baffle is much smaller than the wavelength -- the energy moves omnidirectionally.  In other words, low frequencies "wrap around" the baffle and thus radiate forward and backward (and to the sides).

The result is the bass is (theoretically) ~6dB lower in level.  The wider the baffle, the lower the frequency at which this occurs.  This frequency is the -3dB point, and can be easily calculated.

So wide or narrow, the baffle step occurs unless the speaker is in a corner or against the wall (and in real rooms, it's maybe -3dB typically, because of the boundaries, but 6dB is if there were no such boundaries).

The result is weak bass.  So there are a number of strategies to compensate.  One is to simply add a second woofer (a so-called .5 driver) that only plays from the baffle step frequency and lower.  Another strategy is to use a simple circuit (just a coil and resistor, or use an L-pad for the resistor) to cut (attenuate) everything above the baffle step frequency, thus getting a relatively flat response.

There are multiple other strategies.  For example, in a 2-way, you can get a woofer that is more efficient than the midrange/tweeter (let's say) and put the crossover in the same region as baffle step, and just let the woofer's greater output compensate.

My guess on wide vs. narrow is that both can sound excellent, but narrow baffles have less energy coming off them (diffraction) and that is just what's in style nowadays.  It does seem to improve imaging and off-axis response, but I've heard enormously wide speakers (e.g., Kilipschorns) also sound fantastic.  So ultimately, it's just one ingredient.

A compromise is to use a medium-sized baffle and then put a huge roundover on all the edges.  Or 45-degree chamfer is the next best thing.  Or very thick absorbing material directly on the baffle.  Any of these can help smooth out what the baffle size/shape adds to the frequency response. There's no one perfect approach for all situations so try them all

[JerryLove]

It seems to me that, in many cases, the two prevailing factors for enclosure width (and thus baffle size) are 1) the size of the largest driver, and 2) the enclosed volume desired given the prevailing expected "shape".

While the above poster is completely correct on the issue of baffle-step (which, BTW, can also be resolved by placing drivers *above* the baffle step on both sides of the speaker; creating a more uniform off-axis response by making the entire range nigh-omnipolar), there's a converse issue of reflections.

All those waves bouncing off the baffle not only increase the apparent spl to someone in front of the speaker, they can also smear the point-source and cause "problems" with the sound.. hence the speaker companies that put tweeters in their own separate enclosure (see Bowers and Wilkins).

[jarcher]

Thanks guys for the informative replies.  With the exception of some planar speakers it does seem the wide front speakers have been out of fashion for a long time - I guess because they are seen as more decoratively obtrusive, but the rave reviews of the Devore Orangutan had me wondering if there were any inherent advantages of a wide baffle.  Sounds like the real answer is more complicated than just front baffle sizing choice.

[stereocilia]

It defies my understanding, and really, my brain just cannot wrap itself around how this discussion has completely avoided the obvious pun.

[charmerci]

It defies my understanding, and really, my brain just cannot wrap itself around how this discussion has completely avoided the obvious pun.

I am really baffled about what you are trying to say....

[Quiet Earth]

Here is my narrow view on a wide subject  : 

I think wide baffles speak to the soul whereas narrow baffles appeal to the brain.

I'm not sure if this was mentioned yet, but wide baffle speakers seem more likely to acknowledge that the cabinet contributes to their overall sound, not detracts from it. In other words, the cabinet's voice can be utilized as part of the total sound of the speaker, both in tone and dispersion.

[JerryLove]

I'm not sure if this was mentioned yet, but wide baffle speakers seem more likely to acknowledge that the cabinet contributes to their overall sound, not detracts from it. In other words, the cabinet's voice can be utilized as part of the total sound of the speaker, both in tone and dispersion.

But cabinets are poor reproducers of sound. That's why we have drivers rather than transducers stuck to a piece of wood.

And baffle reflections are , simply put, not good. (as are diffraction problems, but that's not entirely baffle-size dependent.

A perfect speaker would have no baffle. You wouldn't get the +6db from beaming, but since that would be across all frequencies, that would be OK (see: omnipolar speakers). Since you (usually) must have one practically: it's a matter of trade-offs.

[rjbond3rd]

It's very eye-opening to use a baffle diffraction calculator (like The Edge) to predict the baffle's contribution.  Basically, a baffle of any but negligible size tends to contribute a big lump of ripple, and then many smaller ripples thereafter. 

Offsetting the driver far into one corner reduces the effect (but it's still about a dB on what I just tested).  So big improvement but the big ripple and subsequent ripples are still there.  So rounding over the edges and adding absorption would presumably bring down the ripple further.

It would be interesting to see how the response can be improved by a particular baffle shape -- for example, if you have a dip in the driver's frequency response, there is presumably a baffle size / shape that could -potentially- fill in the dip and thus be a positive contribution.  Of course, the sound will diffract off other surfaces, not just the baffle (e.g., furniture, boundaries, etc.)

If you keep morphing the baffle's shape, eventually you get a -very- positive contribution because the baffle has become a horn

[JerryLove]

Rounding the edge deals with diffraction issues, not baffle reflection issues.

Adding felt should positively affect both issues.

Offsetting the driver enlarges the range of frequencies effected, but lowers the SPL increase on the affected frequencies (since you have two baffles, with one very small; rather than two medium baffles reinforcing each other)

Horns are a bit more complex (http://en.wikipedia.org/wiki/Horn_loudspeaker)

[rjbond3rd]

Hi JerryLove,

Can you explain the difference between baffle reflection vs. baffle diffraction?  My understanding is that they are the same phenomenon. 

(Regarding horns, that was my attempt at humor, for a baffle to make a positive contribution as Quiet Earth was mentioning )

[JerryLove]

As I understand it: the dispersion vectors are different. (edge vs baffle) http://www.salksound.com/wp/?p=160

Also, as I understand it, the issue of size is different (why we flush-mount midrange drivers even though the lip would be much smaller than the wavelength. )

[rjbond3rd]

Wow, thank you.  That is a fantastic article.

So I get it now -- it does make perfect sense to separate the "big" effect of baffle step (2pi-to-4pi transition) from "smaller" baffle reflections (ripples) higher in frequency.  Cool.  It is time to get out the router and round some edges!

[Val]

The rave wide-baffled DeVore Orangutan review is just one of several new ones: Spendor SP100R2 by Art Dudley in Stereophile, Stirling Broadcast BBC LS3/6 by REG in The Absolute Sound, and SP Acoustics SP1 by Paul Messenger in HiFiCritic.

[jimdgoulding]

Rounding the edge deals with diffraction issues, not baffle reflection issues.

Adding felt should positively affect both issues.

Offsetting the driver enlarges the range of frequencies effected, but lowers the SPL increase on the affected frequencies (since you have two baffles, with one very small; rather than two medium baffles reinforcing each other)

Horns are a bit more complex (http://en.wikipedia.org/wiki/Horn_loudspeaker)

Just in case you didn't know already . .

                                       www.diffractionbegone.com
 

[Val]

Hi Jim, I bought a pair of those long time ago, need to update my avatar!