Hi,
Here is the story.
I started off trying to build one of the Pure Audio Project open baffle. One way or another, I ended up with 2 pairs of the PAP 15Neo for the low end and a JBL 2441/2397 horn for the top end, with an active DSP crossover and separate amps for each "way".
While the 15Neo are good for mid bass they don't sound as good as my regular speakers for the mid range. I am looking to add a mid-range to cover the ~200 to 1kHz range. Hopefully with a more dedicated mid-range there will be less distortion.
I have a few questions. Since I am doing active crossover, is there still a need to find high Qts drivers anymore? I can EQ and volume match the midrange accordingly in theory. Are there any sonic penalty for doing that?
Which mid-range should I pick? I am browsing through the normal madisound/partsexpress and there are many choices. I don't mind pay a few hundred each if the sound quality justifies it. but seems like most are in the $200-300 range already.
PS. I am not looking for a horn midrange due to size limitations.. 🙂
TIA!
Here is the story.
I started off trying to build one of the Pure Audio Project open baffle. One way or another, I ended up with 2 pairs of the PAP 15Neo for the low end and a JBL 2441/2397 horn for the top end, with an active DSP crossover and separate amps for each "way".
While the 15Neo are good for mid bass they don't sound as good as my regular speakers for the mid range. I am looking to add a mid-range to cover the ~200 to 1kHz range. Hopefully with a more dedicated mid-range there will be less distortion.
I have a few questions. Since I am doing active crossover, is there still a need to find high Qts drivers anymore? I can EQ and volume match the midrange accordingly in theory. Are there any sonic penalty for doing that?
Which mid-range should I pick? I am browsing through the normal madisound/partsexpress and there are many choices. I don't mind pay a few hundred each if the sound quality justifies it. but seems like most are in the $200-300 range already.
PS. I am not looking for a horn midrange due to size limitations.. 🙂
TIA!
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Fs =87, Qt = .19, Xmax = 2.5, is that a driver that would work well to a 200 Hz crossover in OB? By the spec sheet it's already down 5 dB by 200, and that's presumably without dipole cancellation.
JMP,
What are your goals for this speaker (SPL, efficiency, radiation pattern)? Why OB + horn?
I hate to be negative, but in my (somewhat) informed opinion:
That JBL horn is claimed to have 140 degree horizontal dispersion. From what I know about OB speakers that's not a natural match to an OB driver that would have narrower dispersion due to dipole cancellation. That will lead to very irregular polar patterns and a problematic power response. It would also introduce more sidewall reflections, and one of the strengths of dipole radiation is the reduction of those same reflections. A 90 x 60 pattern horn should be a better match.
Crossing over as low as 1kHz, you are giving up dipole radiation over quite a lot of the spectrum, losing some of the spaciousness that is desired by dipole fans (a debatable point, I grant), and further complicating the power response.
FWIW, I'm considering the Faital Pro 10FE200 to cover a similar range (more like 150 to 600). The published plots look smooth, it's flat to below 200 (without dipole cancellation), plenty efficient and they are cheap enough to take a flyer on.
Bill
Hi Bill - I recently made some measurements on the Faital 10FE200, which I was also considering for an open baffle system. I thought you might find them helpful. See attached. The first plot is the frequency response (the front side), on and off axis every 10 degrees or so. The second plot is the harmonic distortion. Keep in mind this was done with the drivers hung in mid air by wires, without any kind of baffle attached.
Attachments
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You will be losing dynamic range by doing a lot of corrections in digital domain. If your baffle is narrow, 200Hz may be 15-20 dB quieter than 1000Hz.
How easy it can be heard I don't know, but the math doesn't look good.
I also have a mid in open baffle and do a lot of corrections in digital domain. Generally, it sounds good, but I always doubt how it could sound if there is no digital correction.
1. Yes and no. You'll have added pressure loss that you'll have to compensate for beyond the baffle dimensions (as it starts becoming an dipole) with lower Qe drivers. But what is the baffle dimension? The PAP design looks like it's at least 28 inches wide.. IF that's the case then you'll likely have a bit of diffraction gain around 250 Hz, with real loss (from the average) occurring at about 100 Hz. Practically speaking this means you won't need a higher Qe driver.
2. IF the above is correct concerning baffle width (plus a larger height for the baffle), then no.
3. I suggested the B200: because it's a low mass driver of larger dimensions with good *linear and non-linear performance in your required pass-band (200-1kHz). It's also got decent excursion (not good or bad) - and should be enough for your application. At $150 they are neither cheap nor expensive.. They are more linear than the Tangband w8-1808 drivers, though that might be moot given the application of digital eq.. Another option would be the Dayton Audio PS220-8. (..Dayton also has a midbass driver based on a similar design, but it has higher Mms.) It also happens that the B200 is a higher Qe driver - allowing you just slightly more flexibility with your high-pass crossover for that driver.
BTW, for others that didn't fully read his post (..Pure Audio Project):
Trio15 Product Line, Open Baffle Speakers – PureAudioProject
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I'd also add that with the B200 option, the possibility exists for phase plugs as well. I enjoyed them tweeter less for a while before I foolishly sold them on
They had great midrange performance IME.
I've always wanted to try the B&C woofer and the 10FE200 also has caught my eye... The way I see it, most of these drivers mentioned have good reputation and would be useful beyond this project or in the hands of another should you choose to move on. Can't go wrong with any suggested so far... At least I'd try em all if I could afford to heh.
They had great midrange performance IME.
I've always wanted to try the B&C woofer and the 10FE200 also has caught my eye... The way I see it, most of these drivers mentioned have good reputation and would be useful beyond this project or in the hands of another should you choose to move on. Can't go wrong with any suggested so far... At least I'd try em all if I could afford to heh.
I use 6fe200 on open baffle, in few projects. Recently in mtm with HiVi big planar tweeter. I used minimalist approach to crossover, absolutely nothing on mids, and only one cap for tweeter. In spite of this it measures well, and sound even better. Very tube friendly. Driving it with kt88 se amp with no preamp is working fine. Sweet sweet sound. Tubes rule.
Try the 9½" Satori midbass, its on my wishlist.
And knowing my self it will be under the tree for christmass.
Has a lot of Xmax so you can easily correct the rolloff with DSP.
Anyway I do not think it matters with Qts when we are talking midrange (200 Hz). That is a lot higher than the fs of all the bass/midranges I can think of.
best regards
uwe
And knowing my self it will be under the tree for christmass.
Has a lot of Xmax so you can easily correct the rolloff with DSP.
Anyway I do not think it matters with Qts when we are talking midrange (200 Hz). That is a lot higher than the fs of all the bass/midranges I can think of.
best regards
uwe
^ 44 Mms for that driver.
Great driver for 50-400 Hz though..
The MR16P-4 is an excellent candidate though (and only slightly higher Mms than the larger B200). ..while it is a "heavier" driver (particularly for its Sd), it has a lot lower non-linear distortion than the B200.
Great driver for 50-400 Hz though..
The MR16P-4 is an excellent candidate though (and only slightly higher Mms than the larger B200). ..while it is a "heavier" driver (particularly for its Sd), it has a lot lower non-linear distortion than the B200.
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Thanks, Charlie! I'll note in particular that you were "considering" that driver, but didn't adopt it. That probably saved me a few bucks.
Bill
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