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Open Baffle Epiphany!

Poultrygeist said:
Welcome to the dark side where thinking outside the box is the norm.

Required reading for any convert to "Open Bafflism" is the huge thread on Audio Circle entitled, "Gravity Well of a Darkstar".

The thread was started some years ago by a brilliant physician/audiophile who is a legend at AC. Richard, one of my favorite posters, offers great insight and descriptions of the OB sound.


http://www.audiocircle.com/index.php?topic=19253.0
Click to expand...

As one who is a little more than di-curious, I was thinking while scrolling this thread....wait for it....wait for it......bam, there's Poultrygeist! :D

Seems like Parts Express has some gorgeous offerings in OB. Hmm. I'm new to the T-amps and such, so this may be a direction I want to go.
 
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Can anyone point me to some good drivers on Parts Express that would be applicable for OB??? Preferably fairly cheap.
 
Check their forum - I think you'll find some OB discussion there.

Generally (and, of course, all generalizations are false, including this one) look for a woofer (or full-range or extended range) driver with high Qts (> 1.0 or so). High sensitivity is good but not strictly necessary.

... or just EQ the bejabbers out of it, I guess.
 
Before I posted, I did, but didn't see much in the way of open baffle.

Didn't know if there was a standout for cheap. Thanks for the generalization. I'm guessing there might be infinite choices that could sound nice.
 
"di-curious" - Now that's funny :yes:

Someone ask about P.E. full range drivers that work in OB.

One of my favorite affordable ones is the Eminence Beta 12LTA. Currently priced at $79, I believe you can find them elsewhere for less. They're big 12 inchers and after cutting out the dust caps their ragged top end gets really smooth. With a cheap tweet they're hard to beat. The $$$$ Emerald Physics use them.

The Dayton PS220-8 is excellent ( a little more pricy at $128 but they're often on sale ) these need a little padding down but have a tremendous upside.

The Tang Band W8-1808 is so rich and refined but the price has doubled since I bought mine. You can buy good used Lowthers for their current price.

For anyone wanting to go cheap the $14 GRS 8FR-8 may be the ticket. They're near clones of the famous Pioneer BOFU which are no longer made. I've used the BOFU in OB with good results. I have the GRS's in a pair of old Realistic Nova cabs and they sure don't sound like $14 drivers.

Many old open back console full range speakers are excellent in OB. I've got a pair of 12 inch Zenith alnico's that are quite good. I should give them away and let someone else enjoy them. I picked up a Fisher console the other day and although I haven't looked at them, I believe it's speakers may have OB potential.
 
mhardy6647 said:
open baffles can be a lot of fun, make no mistake about that.
There is also a lot to be said for point source radiators.

These sounded good (the MR/HF drivers have field coils; the woofers are your standard dynamic - permanent magnet - drivers)...


DSC_5222 by mhardy6647, on Flickr

DSC_5224-1 by mhardy6647, on Flickr

Dave Slagle's...
http://www.intactaudio.com/index.html
EDIT: see also: http://db.audioasylum.com/mhtml/m.h...wmessage=&sort=score&sortOrder=DESC&forum=hug
Click to expand...

Oh yeah, the wife would really go for those.
 
Lavane said:
Here I am locked and loaded ready to dive into building a set of transmission line speakers and I see this thread. I might have to make another trip to the hardware store and get a couple sheets of plywood, and order some full range speakers. :D
Click to expand...

Having built Transmission Line speakers already, and now discovering OB I will chime in my 2 cents.

The Transmission Lines do produce a very nice low end, id say from 80hz down to whatever you design them to. Mine will go down to the high 20's before they fall off (6.5" woofs). The bass seems very organic, not like what you hear in vented or acoustic suspension. The down side I have found is that above the absolute low stuff, the bass is either hit or miss - not a continuous smooth SPL curve until the mid frequencies, say 900hz and above. This could be just my design but I think it is a property of the Transmission Line fundamentals. Also, they are very placement sensitive, some rooms they sound fantastic, some rooms I am lucky to get any useable bass.

OB's from my limited experience (which is very limited) really shine in the musical range, and when hearing this you realize just how much you have been missing with boxed speakers. I am not sure it is realistic to get good bass from a MODEST sized OB without active EQ and bi-amping. Others here have built some big OB's that they claim do get great bass, so I may be way off, some have tried and failed as well.

Transmission Line sub bass with an OB mid/high surely could be magical, I would love to see someone build that. They would end up being mega large, but I bet so would the sound.

My plan is looking like OB full range and a vented woofer for below 200HZ...gotta love a strong low end :thmbsp:
 
Open baffles were akin to a religious experience for me also.

Using University Diffaxials
100 db efficiency.
12 inch woofer.
5 inch mid.
Superb silk dome Sphericon super tweeter.
Getting the great coherency that one gets with point source.

No real lack of bass.
Don't care about all the people pointing at graphs and saying look at the rolloff.
I am not experiencing any big loss of bass.
And the bass is really something special.
Feel like I'm on a first name basis with Ron Carter.

I used them with 6bq5 mono blocks (3 or 4 wpc) and a t-amp (15 wpc) with great success.
They sounded so good with low wattage I went and picked up one of Don Garber's Fi-X Super 300b amps.
Woo-hoo.
No turning back now.

SET amps and efficient speakers in open baffles have given me the best sound I have ever had.

Can't stop listening.
Up late every night.
Not eating properly and losing weight.
Can't focus at work.
My wife is angry with me every day.
Even listening to opera now.

It all just sounds so good.

Art
 
Open baffle...something else I've got to try.

I've still got the Magnavox cabinet my amp came out of, I guess I need to take a look at the drivers and see if they have potential.
 
Poultrygeist said:
"di-curious" - Now that's funny :yes:

Someone ask about P.E. full range drivers that work in OB.

One of my favorite affordable ones is the Eminence Beta 12LTA. Currently priced at $79, I believe you can find them elsewhere for less. They're big 12 inchers and after cutting out the dust caps their ragged top end gets really smooth. With a cheap tweet they're hard to beat. The $$$$ Emerald Physics use them.
Click to expand...

I forgot about the ol' 12LTA :-) - used in the ol' Hammer Dynamics speakers with helper tweeters. I tend to think of it as a latter-day EV LS12 :-)

So- once the dust cap is removed... did you add a phase plug or just leave it as is?

The Dayton PS220-8 is excellent ( a little more pricy at $128 but they're often on sale ) these need a little padding down but have a tremendous upside.

The Tang Band W8-1808 is so rich and refined but the price has doubled since I bought mine. You can buy good used Lowthers for their current price.

For anyone wanting to go cheap the $14 GRS 8FR-8 may be the ticket. They're near clones of the famous Pioneer BOFU which are no longer made. I've used the BOFU in OB with good results. I have the GRS's in a pair of old Realistic Nova cabs and they sure don't sound like $14 drivers.

Many old open back console full range speakers are excellent in OB. I've got a pair of 12 inch Zenith alnico's that are quite good. I should give them away and let someone else enjoy them. I picked up a Fisher console the other day and although I haven't looked at them, I believe it's speakers may have OB potential.
Click to expand...

The above mentioned "GRS 8FR-8" is indeed not a bad sounding driver on OBs; I've got a pair somewhere in the rubble.
 
mhardy6647 said:
I forgot about the ol' 12LTA :-) - used in the ol' Hammer Dynamics speakers with helper tweeters. I tend to think of it as a latter-day EV LS12 :-)

So- once the dust cap is removed... did you add a phase plug or just leave it as is?
Click to expand...

Yes, please elaborate. I can spring for something like that.

And, since one has to add a tweeter, is this where bi-amping comes in? Can't see a passive crossover with OB, would appear to defeat the whole sound approach. I'm green on this, so bear with me.

I have two Epi tweets that I'm currently not using. I wonder if these and some of the Eminence you mentioned would play well together.
 
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