Hello. I am thinking about building a 3 way open baffle speaker. I am thinking of using the Scanspeak Discovery 10F/8414G-10 full range driver.
Details here: https://www.madisoundspeakerstore.c...canspeak-discovery-10f/8414g-10-4-full-range/
Would this driver be suitable for open baffle? If so, what is the lowest XO point it could manage? The maximum I can do is around 550Hz, so I would have to choose a different driver otherwise. My hope is to cross the driver with a tweeter at at least 5KHz, so ideally I would love to stick with a driver under 5".
If anyone has some related advice that is not strictly related to my question, I welcome it! Thank you in advance for anyone's input!
Details here: https://www.madisoundspeakerstore.c...canspeak-discovery-10f/8414g-10-4-full-range/
Would this driver be suitable for open baffle? If so, what is the lowest XO point it could manage? The maximum I can do is around 550Hz, so I would have to choose a different driver otherwise. My hope is to cross the driver with a tweeter at at least 5KHz, so ideally I would love to stick with a driver under 5".
If anyone has some related advice that is not strictly related to my question, I welcome it! Thank you in advance for anyone's input!
550 Hz should be OK, it will go lower but with higher higher 2nd order distortion down to about 250 Hz at which point the other harmonics start getting a lot louder. This of course completely depends on the size of the baffle. IF you are trying to maximize it's dipolar character with little or no baffle then you need to push the freq. higher for its low-pass (nearing 900-1kHz).
4.5 kHz is about as high as you should go when factoring-in off-axis integration.
The tweeter should be something with not much of face-plate so that you can push the tweeter as close to the midrange's frame as possible. Considering it's open-baffle I'd look to the Neo3 variations (BG original, Sounderlink, or GRS) and do something like the Nao Note:
http://musicanddesign.speakerdesign.net/NaO_NoteDetails.html
4.5 kHz is about as high as you should go when factoring-in off-axis integration.
The tweeter should be something with not much of face-plate so that you can push the tweeter as close to the midrange's frame as possible. Considering it's open-baffle I'd look to the Neo3 variations (BG original, Sounderlink, or GRS) and do something like the Nao Note:
http://musicanddesign.speakerdesign.net/NaO_NoteDetails.html
4.5KHz! Exactly the sort of extraneous tip I was hoping for! Thank you!
I was thinking about the GRS tweeter, but I was also thinking about using a regular tweeter. I have heard from some folks that dipolar sound is better left to lower frequencies, and while I know that's not always the case, I have heard you can certainly get good results this way. My thinking was a dome tweeter in a waveguide. With the configuration that I have thus far laid out, do you think this would work ok? Thanks again 🙂
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Well, a true Cardiod isn't that directional with -6db at +/-90 degrees and only about -3db somewhere near +/-50 degrees.. In fact, your tweeter will likely have more pressure loss than this off-axis at higher freq.s (above 6 kHz or so).
Still, I think a large baffle can make for an excellent speaker. Perhaps aesthetically like a larger version of the SF Elipsa see below (but open baffle, not cabinet based)
I would NOT do a waveguide tweeter. A (typically larger) waveguide tweeter is done to lower the crossover freq. (high-pass for the tweeter). Additionally, most will NOT be dipolar (unless you double-up and put one on the back of the baffle and wire it out-of-phase).
https://www.stereophile.com/images/archivesart/1207sonus1.jpg
Still, I think a large baffle can make for an excellent speaker. Perhaps aesthetically like a larger version of the SF Elipsa see below (but open baffle, not cabinet based)
I would NOT do a waveguide tweeter. A (typically larger) waveguide tweeter is done to lower the crossover freq. (high-pass for the tweeter). Additionally, most will NOT be dipolar (unless you double-up and put one on the back of the baffle and wire it out-of-phase).
https://www.stereophile.com/images/archivesart/1207sonus1.jpg
I understand that it would not be dipolar. As I said in my previous comment, I have heard that you can achieve excellent results with a dipolar lower end mated with a non-dipolar (unipolar?) high end. The Spatial Audio Sapphire M4 (pictured here) comes to mind, which uses the Peerless Corundum dome tweeter.
I understand that a huge draw of waveguides is to allow for a lower crossover point, but my objective there would be to achieve a uniform-ish dispersion
By the way, that Elipsa is absolutely gorgeous! I will definitely be looking at that when it comes to my cabinet design!
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But remember - you want to get the tweeter as physically close to the midrange as possible to have better vertical integration off-axis, particularly in the case of a crossover freq. as high as 4.5 kHz.
Note: an open baffle tweeter almost always sounds better with an open baffle design than a typical monopole, this is why you will even see designs with two monopoles (typical sealed tweeters with one on the front and one on the back) wired out-of-phase to get more higher freq.s reward of the baffle).
Again, a Neo3 (variant dipolar/no-back-cup) at 4.5 kHz -up is nearly ideal for your large baffle design. It doesn't hurt that these planars tend to sound better than even very expensive dome tweeters.
Note: an open baffle tweeter almost always sounds better with an open baffle design than a typical monopole, this is why you will even see designs with two monopoles (typical sealed tweeters with one on the front and one on the back) wired out-of-phase to get more higher freq.s reward of the baffle).
Again, a Neo3 (variant dipolar/no-back-cup) at 4.5 kHz -up is nearly ideal for your large baffle design. It doesn't hurt that these planars tend to sound better than even very expensive dome tweeters.
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A couple of these would work well below about 300 Hz, so if you don't mind "pushing" the mid. a bit (as long as you have a large baffle) and have a fairly steep high-pass then it's a worth-while consideration:
http://www.sbaudience.com/index.php/products/various-drivers/bianco-12ob150/
Note: you'll still want a subwoofer with a design like this.
http://www.sbaudience.com/index.php/products/various-drivers/bianco-12ob150/
Note: you'll still want a subwoofer with a design like this.
Hm. You're right. I have been coming short on thinking up how to closely locate the two drivers going with the waveguide idea. It would help with the z axis alignment, but the vertical alignment would be less than ideal.. well, if it helps, here is what I had in mind for the tweeter.
https://www.somasonus.net/sb-acoustics-sb21
https://www.somasonus.net/peerless-vifa-ot19nc00-04
Either of these two have seemed appealing to me, and they have an ovular shape to them, which would slightly help with the vertical positioning issue.
That said, that still does not confront the issue you mention about monopole configurations typically not sounding as good. Why is that?
I am not very knowledgeable about this subject, but I have seen very good designers make speakers that seem to ignore your statement (eg troels Gravesen with his OBL-15 design http://www.troelsgravesen.dk/OBL-15.htm). In that design, he even used a waveguide! (Although at a much lower XO point)
Are these designs you would intuitively dismiss? (Asking honestly, not confrontationally, your advice and input is very much appreciated!)
Oh awesome! You know I was actually thinking that I would probably use an SB driver for the bass! I will do some research on what you've linked.
("Sounding Good")
Based on personal experience and from others that are well respected.
Note that *Linkwitz and **JohnK both started with the monopole tweeter idea - in time their designs progressed to dipolar higher freq.s.
*Linkwitz was pretty much THE open baffle designer.
**JohnK was his contemporary (and also the designer of the Note that I linked to before).
Initially neither thought it was that worth-while for a dipolar tweeter, but after several revisions realized there error. 😉
Based on personal experience and from others that are well respected.
Note that *Linkwitz and **JohnK both started with the monopole tweeter idea - in time their designs progressed to dipolar higher freq.s.
*Linkwitz was pretty much THE open baffle designer.
**JohnK was his contemporary (and also the designer of the Note that I linked to before).
Initially neither thought it was that worth-while for a dipolar tweeter, but after several revisions realized there error. 😉
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2 per loudspeaker.
Remember: increased surface area and excursion are needed to compensate for substantial pressure loss due to dipole operation.
Tip: keep your midbass drivers (SB Audience 12" driverS) on their own baffle or mechanically de-couple the midrange and tweeter from the main baffle that the 12" driverS are connected to. (..they will make a LOT of vibration.)
Can't argue with that! I didn't know Linkwitz started with monopole, and I honestly am not familiar with JohnK.
Alright, that has done a lot to convince me, but I will do some more research before making a decision. I know Linkwitz has a TON of writing on this subject, so maybe I'll check that out.
One more thing though. Humor me 🙂
If at the end of my research, I decide that I know better than the late and great Linkwitz (I know I never will 😛) and decide to do a monopole tweeter after all.. do you reckon either of the tweeters with those waveguides I linked would integrate well with the Scanspeak full range?
Ok. Noted. I actually was planning on this, but it is always nice to hear a confirmation by someone more knowledgeable than me 🙂
Depends on what you do with it. It would be utterly *unsuitable at 4.5 kHz high-pass.
A typical 2nd order low-pass at around 1.4 kHz however would be good (with the right tweeter and waveguide), but you might be better served with a larger driver than the Scanspeak fullrange (especially depending on the rest of the design) in that context.
*well, maybe a 1st order design with the tweeter/waveguide tilted just right vertically for the listener and with the listener at just the right distance for "integration" with respect to vertical dispersion. (..in-room power response though will still likely have some depression in the bandwidth near the crossover.)
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Interesting. I guess my mission statement with this speaker here is to make something that approximates the sound of a full range speaker, but has the support of a couple other drivers to handle the frequency extremes. With that in mind, I am definitely married to the idea of a higher crossover point.
Why would 4.5KHz be unsuitable? (If it's too complicated to simply explain then that's ay ok. I would hate to overstay my welcome in your pool of knowledge 😊)
Again, problems with center to center distance between the tweeter and the midrange. Plus, what is the waveguide really doing for your tweeter? It's mostly ******* away your spl well off axis (trading it for a bit more closer to on axis).
Well good but very low sensitivity for OB.
Even two in parallel, as this is 16 ohm, will not get you enough SPL on an OB.
Some people will say Amp Watts are cheap, but the cheapest and most satisfying way to build an OB is to use high sensitivity drivers especially at the bottom. Otherwise you are missing the magic (of OB).