To high, and also to low for first order..
6" and higher diameter midbass drivers (efficient ones) are almost certainly going to require a lower freq. high-pass for the tweeter (and a lower freq. low-pass for the midbass).
You need to be thinking about a higher-order lower freq. crossover with 6" drivers (or even larger drivers).
Again:
"IF you go with a higher-order design AND you cross-over lower than you should (near *2 kHz with a steep high-pass), THEN the Faital Pro (16 ohms in parallel) could work very well.
*maybe 2.2-2.3 kHz?"
https://www.diyaudio.com/forums/multi-way/346413-sensitivity-3.html#post6009577
Go back and look at the on and off-axis performance of the more linear 6" from Faital Pro:
Test Bench: Faital Pro 6RS140 Midwoofer / Midrange | audioXpress
6" and higher diameter midbass drivers (efficient ones) are almost certainly going to require a lower freq. high-pass for the tweeter (and a lower freq. low-pass for the midbass).
You need to be thinking about a higher-order lower freq. crossover with 6" drivers (or even larger drivers).
Again:
"IF you go with a higher-order design AND you cross-over lower than you should (near *2 kHz with a steep high-pass), THEN the Faital Pro (16 ohms in parallel) could work very well.
*maybe 2.2-2.3 kHz?"
https://www.diyaudio.com/forums/multi-way/346413-sensitivity-3.html#post6009577
Go back and look at the on and off-axis performance of the more linear 6" from Faital Pro:
Test Bench: Faital Pro 6RS140 Midwoofer / Midrange | audioXpress
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ok....this morning comparing a pair of the above M130-16 5.25" mid-woofers with this SB driver:
https://meniscus.lightningbasehosted.com/wp-content/uploads/2015/11/SB15NRXC30-4-Data-Sheet.pdf
Similar sensitivity.....around 91db for both; I understand 2 drivers in parallel will play louder with less distortion than one.
The pair or M130 drivers need 13L in a sealed box for F3 of 90hz
One SB15NRXC30-4 driver needs 4L in a vented box for F3 of around 80hz
Since all of my tube amps (except the 2W SET) have both 8R and 4R speaker taps, I'm assuming output impedance/damping factor is equivalent between 4 and 8R.
What are reasonable XO freqs for these two drivers? ...seems like the off-axis response starts to attenuate around 2Khz for both of these drivers.
Hey buddy!
If I'm thinking about this correctly, the output impedance should be somewhat lower in the case of the 4 ohm tap, and damping should be somewhat better than for 8 ohms, but it's not going to matter a ton.
The off-axis attenuation will be present on almost all drivers of a given size. For the one you showed, 2k is a good choice as you get that little BBC dip to start with. The problem is that ribbons don't like 2k for the most part, they're happier up near 4k+, typically, and not with first order for sure.
For a ribbon you really do want to go with a 3 way almost universally- otherwise you have a laserbeam midwoofer (high directionality) and effectively an omni tweeter (due to narrow ribbon design). This abrupt change to dispersion will be very audible.
I'd try my best to get creative about fitting some larger systems into the application- high efficiency really does need decent size, but it doesn't need to be width, it can be a mix of depth and height (which is ok). For the Mid/Tweet and using a ribbon I strongly recommend doing a very small MTM with two 4" or so. You still get a small array and associated behavior, but you get a few things from this route.
Efficiency of 2 drivers
Narrow vertical pattern both above and below the M/T XO point
Reasonably wide dispersion for both the ribbon and the smallest reasonably efficient mids you can use
You can XO to a more efficient woofer at baffle-step freq to mitigate the need for maximal mid efficiency (it only needs to match the ribbon, not be efficient enough to match the ribbon AFTER baffle step compensation).
Hey! Ashland, MA!! wow...long way from So Cal.....I grew up in MA.....
The 4 ohm taps reflect the same load on the output tubes (say 5K) as the 8 ohm taps....
OK..so back to finding a full range driver that I can cross over at 8K-10Khz......small with high sensitivity....
Well...I think of this as a 3-way....with the 12" woofer in a separate box with it's own amp and LP filter....
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Yeah, had to come out here after we stopped getting together... it was the only thing keeping me out there. KIDDING!
Yes, my thinking around the taps is just around winding ratio- you'll have a lower secondary DCR on the 4 ohm taps and thus potentially some slight differences accordingly.
The MCM 55-1200 used to be a good choice for higher efficiency small woofers but it's NLA, I didn't see anything equivalent at Newark. It's worth checking through the Visaton product offerings thoroughly as they tend to do more small higher-efficiency drivers than many other shops.
Badman's suggestion of a 3-way is a VERY good idea, and it doesn't have to be super large either and can still be efficient (as long as you aren't expecting much bass extension).
The SB is a 4 ohm driver - meaning it's current requirement net's about -3db below that of an 8 ohm driver.
If you connect them in SERIES for an average 8 ohms, you'd generally end-up with neither gain nor loss: so you'd be at the same as a single 8 ohm driver that was 91 db = which is not particularly efficient.
You could however go as high as 3 to 3.5 kHz for a crossover freq. with something like an LR 2nd order (for at least the high-pass/tweeter) for the SB. Again though, the higher you go the more problems you could have with your vertical response in relation to both drivers playing the same upper freq. while necessarily have distance between the two drivers.
Now the GR Research driver you might be able to use without much of a low-pass filter (though this doesn't mean that the driver won't need correction). IF correct, this could allow a 1st order up quite high in freq. for the tweeter. You'd still have to be wary of vertical combing/suckout limitations, so the vertical listening "window" would still be quite narrow.
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Ex.
1x Faital 3FE20 (8 ohms)
FAITAL 3FE20 (extended-range 3", 8 Ohm, 40 Wmax)
2x Faital 6FE200 (16 ohms connected in parallel) in an aperiodic box.
FaitalPRO | LF Loudspeakers | 6FE200
Because ribbons and 2 ways are very challenging? Troel's Fostex/Neo CD 3.0 XO is about 3600Hz (3rd order) and his SEAS/Neo project appears to be much lower XO, although 4th order...not sure the exact XO freq on that one.....
I was planning on just running a single 4 ohm SB midbass and live with 91db....and maybe a little less with BSC...or use 2 8 ohm versions of the same driver in parallel. The 8 ohm version is 88db I think..as expected. Every amp I have except the 2W SET can drive 4R loads. Two 8 ohms in parallel nets 3db or 6 db gain???
Horizontal response suffers with higher XO as well, correct? But I should stay at least 3 octaves above ribbon FS? FS=1400 so 4000hz or so seems do-able..although perhaps not first order....I'm assuming that's the compromise between horizontal off axis response and keeping the tweeter alive and well...
Why does this driver (or pair of 16 ohm drivers) allow higher XO than the others? .....seems like horizontal off axis response on even that flat 5" drivers falls off around 4000hz. Is the vertical combing from MTM arrangement or TMM?
Typically you look at your midbass around 180 Hz: about 93db + another +3 db of acoustic gain (for 2 drivers), so about 96db not including any gain from a smaller aperiodic cabinet around 180 Hz. Maybe another +1 db from some current-to-voltage gain from the net 8 ohms, it depends on how your amplifier reacts to the load.
You'll likely have some baffle-gain below 1.5 kHz, depending on the baffle width - which should extend the 3FE20 response average to about 93-94 db: good for your Tweeter. It's of course excellent with respect to off-axis performance and it extends quite high in freq.. (..for subjective performance I'd do this in a tube-enclosure (within/bisecting the cabinet with the 2 six inch drivers) with a bass-reflex port and a low tuning freq. (..say 70 Hz), but with of course an appropriate high-pass filter.)
Done properly it should give you most of what you are looking for.
You'll likely have some baffle-gain below 1.5 kHz, depending on the baffle width - which should extend the 3FE20 response average to about 93-94 db: good for your Tweeter. It's of course excellent with respect to off-axis performance and it extends quite high in freq.. (..for subjective performance I'd do this in a tube-enclosure (within/bisecting the cabinet with the 2 six inch drivers) with a bass-reflex port and a low tuning freq. (..say 70 Hz), but with of course an appropriate high-pass filter.)
Done properly it should give you most of what you are looking for.
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I'm confused..the 3FE20 is 8 ohms and 91db.....
Do I get +3db or +6db for two driver parallel connection?
Just a single driver.
Look more closely at the pressure above 2.4 kHz, and then factor-in baffle/diffractive gain below this (..depending on the with of the enclosure). There should also be a small amount of pressure gain above (freq.) this major component of diffractive gain, along with a narrow-band dip. (..try to center the dip around 2.5 kHz.)
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Ok...a bit lost here.....Are you proposing a 3 way design with Fountek then 3FE20 and a pair of 6FE200's?
Dec ware 944/945 Silver Flute woofer & HiVi tweeter. Only 1 cap on the tweeter, nothing on the woofer. 94 dB
Simple Silver Flutes 2 Way
Decware DM944 Bookshelf Loudspeaker Reviewed
AudioRoundTable.com: Speaker >> 94 db speaker
from decware forum 944/945 speakers
"The 944's used a 3.9 cap while the 945's use a PX3.3 ClarityCap. You could go all the way up to the MR range if you like."
Simple Silver Flutes 2 Way
Decware DM944 Bookshelf Loudspeaker Reviewed
AudioRoundTable.com: Speaker >> 94 db speaker
from decware forum 944/945 speakers
"The 944's used a 3.9 cap while the 945's use a PX3.3 ClarityCap. You could go all the way up to the MR range if you like."
Thanks for the replies everyone! I'm hip deep in a Parts Express Bluetooth speaker build this weekend but I'm still keenly interested in this project..it's next.
That Silver Flute DECware project is refreshing....8" 2 way 93db...cheap too....
To reiterate my goals here.....
Small 2-way (hoping 5.25" or 6" mid woofer)..I have no issues doubling up mid woofers..although that means less small. Needs to get down to around 100-120hz (I have a 12" sub..and have parts to build another same thing...)
high sensitivity (93db or better)
Has to use a ribbon ( I bought the Neo CD 3.0 years ago after hearing some nice ribbon designs...at the time I was playing with Heil AMTs..I have since sold them)
As I mentioned above..the Parts Express 3" full range "point source" drivers arrived for the bluetooth project and I slapped together a pair if sealed 7L boxes for them and put them in the main system.
Imaging was surprisingly good, but obviously just lacked dynamics and SPL...as expected.
That Silver Flute DECware project is refreshing....8" 2 way 93db...cheap too....
To reiterate my goals here.....
Small 2-way (hoping 5.25" or 6" mid woofer)..I have no issues doubling up mid woofers..although that means less small. Needs to get down to around 100-120hz (I have a 12" sub..and have parts to build another same thing...)
high sensitivity (93db or better)
Has to use a ribbon ( I bought the Neo CD 3.0 years ago after hearing some nice ribbon designs...at the time I was playing with Heil AMTs..I have since sold them)
As I mentioned above..the Parts Express 3" full range "point source" drivers arrived for the bluetooth project and I slapped together a pair if sealed 7L boxes for them and put them in the main system.
Imaging was surprisingly good, but obviously just lacked dynamics and SPL...as expected.
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