MWalt
Super Member
What kind of sensitivity or efficiency levels are we looking at with these drivers in an OB configuration with a ribbon or Heil type tweeter?
Open Baffle Epiphany!
- Thread starter cptnCanada
- Start date
What kind of sensitivity or efficiency levels are we looking at with these drivers in an OB configuration with a ribbon or Heil type tweeter?
tomlinmgt
Lunatic Member
Unless you're planning on using passive networks, which I would discourage, it shouldn't be an issue. An active xover or MiniDSP will allow you to adjust output levels for each individual driver.
But I'm not so sure the Dipole 15's can play up high enough to meet a Heil or ribbon. Pretty sure you'd need another driver to couple the two. And at that I probably wouldn't want the Heil playing down much in the mid range as I'm not too keen on the idea of splitting mid range reproduction between two different drivers.
I have four AE IB15's....close relatives to the Dipole 15's.....that I'll soon be prototyping with, shooting to recreate something along the lines of the Lotus Group Grenada, perhaps (but without that insane field coil driver). I have other ideas, but first need to determine how high up I can get them to play. It's certainly a concern I need to address and measure before I proceed with any ideas because I can't find measurements/response curves anywhere. Dave, you probably already know or have an idea. Can you throw me a bone? Being designed for infinite baffle I'd be surprised if it did much above 250.
The Grenada, for anyone interested...
http://lotusgroupusa.com/Granada.htm
- Michael
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Poultrygeist
Lunatic Member
Here's the $5000 Emerald Physics with those "entry level" 
Alpha woofers.
Alpha woofers.
MWalt
Super Member
Damn, I forgot to mention that a full ranger would be used in between. I need to quit flirting around with the idea of OB's. I just don't have the space.
tomlinmgt
Lunatic Member
I wonder if the Linkwitz Plutos would work in your room....:scratch2:
dnewma04
The Healer
I'd have two primary concerns with pairing dipole 15s to something like a Heil or a small ribbon, one of which you described very well. The best implementation of Heils I've heard have always used them as a tweeter in a 3 way, or in the very least, a higher crossover frequency than their specs lead you to believe. Cross them over at 1000hz and you're asking for trouble, cross them over at 2k and they are a very fine tweeter. You can get lower, but they start needing very steep slopes. Big ribbon tweeters or planar dynamic speakers like a BG RD75 can go much lower and can perform superbly mated up to a couple of pairs of large diameter OB drivers.
The second concern is power response. The polar response of a 15" woofer is going to look significantly different than the ribbon/heil anywhere near the crossover freq. The problem may be slightly curtailed going OB, but any reflected material will have a different sonic character than the direct signal.
I believe they still use the copper shorting rings which does a great job of keeping Le linear (and low) throughout the stroke of the woofer. I wouldn't be surprised to see that it could play nicely up into the 400-500hz range, if not higher. The dust cap may start to come into play above that. I believe the only time I've seen them used in a non-subwoofer application was with RD75s in an inwall system where they were crossed over at 300-400hz.
Those look nice.
dnewma04
The Healer
FWIW, I plan on using Dipole 15s with a couple of future electrostatic projects. I have some panels from ML CLS speakers as well as some small electostatic panels that show a lot of promise. I might just go with a 2 way with the dipole 15 to make it easy. I'll document the build when I get it all worked out.
nailer
audionerd
Here's the $5000 Emerald Physics with those "entry level"
I need an audio epiphany and if it's going to happen it will be through speakers. Would these be a viable representative of OB design for the non DIYer?
tomlinmgt
Lunatic Member
Hell yes they would....or at least I'd say so based on the reviews I've read. There was a set on our local CL last week....the first generation. Seller was a little proud of them. Did you see them?
Poultrygeist
Lunatic Member
Absolutely. I've used all the same drivers in OB bi-amped with an active crossover and the sound is remarkable.
Here's a poor man's DIY version of the Emerald Physics using four Alphas, Vifa tweeters, Dayton wave guides and a Behringer active. The author states these can be built for around $700 but when I add up the part's cost I get a lower total.
http://www.tweakaudio.com/EVS-2/Modding_the_Emerald_Physics_spe.html
Poultrygeist
Lunatic Member
Here's a link to Martin King's OB build using the Alpha 15 woofers.
http://www.quarter-wave.com/Project09/Project09.html
http://www.quarter-wave.com/Project09/Project09.html
tomlinmgt
Lunatic Member
Hey Nailer...let's build you a set of those! Seriously! I have the tools and facilities......those look too easy to not try!
tomlinmgt
Lunatic Member
I guess my only question as a skeptic is: If OB speakers offer so much more, why aren't they marketed widely / more popular? Is it just a case of old technology setting standards and people are skeptical? like me
They're difficult to market to the average consumer/enthusiast because of their appearance (large size, naked drivers in the rear, among other ingredients that add up to low WAF), unique placement requirements (they have to be three to four feet or more out from the wall behind them), complex power and filter requirements (usually require multiple amps and active crossovers), and they defy conventional thought and attitudes....just as you've demonstrated.
Jim Shearer
Active Member
I guess my only question as a skeptic is: If OB speakers offer so much more, why aren't they marketed widely / more popular? Is it just a case of old technology setting standards and people are skeptical? like me
1) OBs are big & low WAF. Beauty is in the eye of the beholder, and many people think they are butt ugly.
2) IME, they need a a good sized room; need to be at least 3' out from the front & side walls.
3) the sonic presentation is VERY appealing to some folks, while others absolutely loath the reflections from the front wall.
If you haven't listened to OBs, you should, just so that you know what they are like. And as with speakers in general: no two sound alike, and no two rooms sound alike.
And let me also suggest that while you are at it, you check out some good single full range drivers as well. Why not check out all that audio has to offer?
Cheers, Jim
tomlinmgt
Lunatic Member
No doubt....I've always viewed this hobby as if I'm walking into a Baskin Robbins (are they even around anymore?). Keep those little pink spoons and flavors comin'!
NeonDriver
Well-Known Member
Back to crossover frequencies for a moment... My drivers are 15" two way coaxials with a crossover around 2 khz with lots of overlap. There was a time not so long ago that I thought a 15" two way would never work well. Well, times have changed. I get very nice midrange from the 15" driver and I cannot detect the crossover point whatsoever by listening.
I suspect the coaxial arrangement helps to make the crossover region more transparent due to the point source nature of the driver. The dipole arrangement probably helps too. I also think the pro style drivers have lighter cones and play better into the upper ranges than a relatively heavy woofer.
I suspect the coaxial arrangement helps to make the crossover region more transparent due to the point source nature of the driver. The dipole arrangement probably helps too. I also think the pro style drivers have lighter cones and play better into the upper ranges than a relatively heavy woofer.