Why are you complicating the design by adding in a 'way' you don't need. The 17NAC will easily go to 2.5kHz and the T25B will easily go down to 2.5kHz. Sure there will be a directivity mismatch but you were going to have off axis issues between the huge faceplate MD60N and T25B anyway.
To resolve the directivity issues put the T25B in a waveguide, even just a small one, and cross it at 1.5kHz to the 17NAC. Or put it in a 6" waveguide, for a directivity match with the 17NAC, cross at 2.5kHz and put up with the slightly worse vertical off axis.
The MD60 is an odd driver and introduces significant compromises elsewhere in the system. Realistically it should only be used in a 4 way system and over a very small bandwidth, where a very high SPL system is required. If you don't need to reach stupid SPLs drop it as an idea and go with something far more suitable. Clearly you need a smaller system to go in a smaller room and without huge SPL requirements.
In my opinion, when using a dome midrange, it should be the main attraction of the speaker and not a filler driver. TB and ATC/Volt got this right with their 3" domes and their ability to crossover at 400Hz. Use a 10" bass driver below it and a 1" tweeter above it, like ATC do, for a complete three way system. SB optimised the specs on the MD60 really poorly imo for most modern hifi usage, especially with the large c2c spacing the dome necessitates. Sure cross it at 2kHz, for good vertical off axis, but then cross it at 800Hz for a reach of 800Hz-2kHz? No thanks.
The RS52AN is the perfect dome to compliment an RS225, or similar, an 8" three way, or go with something like the 7" metal cone illuminator bass drivers. Basically 7-8" drivers that struggle to get to a tweeter but have excellent bass performance. Cross as low as the 52 will go and put a small neo dome above it.
For the MD60 I'd want to put a 15" pro bass below it, 10" pro above that, MD60 followed by a Beyma TPL or something. Crossovers 250Hz, 900Hz, 2.5kHz. All drivers given very narrow passbands and will go stupidly loud. Except in all honesty I'd rather match the pro 10" to a decent 10" waveguide and skip the MD60 altogether. With its very limited low end extension there are very few systems where it actually makes sense.
By all means go for it if you must use the MD60. I was excited when it was announced. I thought it would be like SBs good tweeters, ie can play very low for a 1" dome, so this would play very low for a 2.5" dome. Sadly no. It'll still be a nice speaker, just a needlessly complicated one. And if you love the sound of the metal cone just go 17NAC straight into Be tweeter. Heck the SB15NAC will go to 150Hz without any bother too...
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Agreed with pretty much all your points. If it wasn't for the relatively low sensitivity (which is less important in near-field or active), the SB65WBAC25 would render the MD60 completely useless in every application.
Oh my... did you breath while writing that ... LOL. Seriously, thanks for the input the 5th element, and I guess I could do a simpler loudspeaker. A 3-way would be more than sufficient.
So if we adjust the lineup, it could look like this:
Tweet: Bliesma T25B-6 (1")
Midrange: SBA SB17NBAC30 (6")
Bass: SBA SB29NRX75-6 (10")
So only 3 drivers instead of the 5 which comprised the 4-way. I can do a 4-way at a later time.
Regarding waveguide. Some time ago, I got the opportunity to listen to the YG Acoustics Hailey 2.2. What stood out was the dispersion... it had one of the better I've ever heard. I don't have any driver data, but the waveguide they use in combination with a flanged baffle was part of it. So a waveguide like that has been on my mind for a while.
It uses a 1", 7.25" and 10.25", mid and woofer is Alu while the tweeter is their textile dome. - very nice performing loudspeaker.
So if we adjust the lineup, it could look like this:
Tweet: Bliesma T25B-6 (1")
Midrange: SBA SB17NBAC30 (6")
Bass: SBA SB29NRX75-6 (10")
So only 3 drivers instead of the 5 which comprised the 4-way. I can do a 4-way at a later time.
Regarding waveguide. Some time ago, I got the opportunity to listen to the YG Acoustics Hailey 2.2. What stood out was the dispersion... it had one of the better I've ever heard. I don't have any driver data, but the waveguide they use in combination with a flanged baffle was part of it. So a waveguide like that has been on my mind for a while.
It uses a 1", 7.25" and 10.25", mid and woofer is Alu while the tweeter is their textile dome. - very nice performing loudspeaker.
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If you're willing to go a bit larger and spend a lot more money, the Purifi PTT6.5 might (based solely on measurements, at this point) be a considerably better midrange driver than the SB.
Also, I personally wouldn't use a Be tweeter without some sort of grill. I'd love to use a T25B in a waveguide, but I'd be constantly worried about it being broken by small fingers. Now, if someone would come up with a way to make a waveguide for it with a grill ....
Also, I personally wouldn't use a Be tweeter without some sort of grill. I'd love to use a T25B in a waveguide, but I'd be constantly worried about it being broken by small fingers. Now, if someone would come up with a way to make a waveguide for it with a grill ....
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Well, that depends. In a 3-way, you wouldn't expect a 6" to go down below 200-300 Hz, nor above 1.8-2.5 kHz. Using 96 dB @ 1m as a reference level, we see the following from 200 Hz to 2 kHz for the two drivers:
Purifi:
- slightly better H3, averaging at about -65 dB
- about the same level of H4, averaging at about -85 dB
- slightly worse H5, averaging at about -80 dB
- frequency response & waterfall are both equally very smooth
- breakup frequency (which the driver should not be reproducing anything at, ideally) is not that high, centered at about 3.5-4 kHz. If I had to cross at 2 kHz I wouldn't use anything shallower than a 4th-order low pass (maybe a 2nd-order at 1.6-1.8 kHz)
- IMD looks OK, but the SB has no IMD data to compare with
SB:
- slightly worse H3, averaging at about -62 dB
- about the same level of H4, averaging at about -86 or -87 dB
- slightly better H5, averaging at about -80 dB also, but with less of it ending up at the frequencies we are most sensitive to (3-5 kHz region)
- frequency response & waterfall are both equally very smooth
- breakup frequency is very high, centered at about ~7 kHz
Depending on what you are looking for, the Purifi could be a better driver, but in terms of value in a 3-way or 4-way, the SB is definitely better IMO. In a 2-way that needs more bass output and power handling, the Purifi would be way better.
1. A grill can be included, but I'm not worried. I don't have children 
2. The PTT6.5 is interesting.. I will go over some reviews since there are some that now have this in their home.
3. Doing a 3-way inspired by YG Acoustic Hailey 2.2 with tapered tube absorbers (Vivid Audio style).
4. With an active 3-way DSP and class A/B on the tweet and mid while using the Purifi 1ET400 on the woofer.... all sounds like hell of a nice combo.
2. The PTT6.5 is interesting.. I will go over some reviews since there are some that now have this in their home.
3. Doing a 3-way inspired by YG Acoustic Hailey 2.2 with tapered tube absorbers (Vivid Audio style).
4. With an active 3-way DSP and class A/B on the tweet and mid while using the Purifi 1ET400 on the woofer.... all sounds like hell of a nice combo.
Right and I agree. The Purif is a very nice driver, perhaps among the better paper driver on the market. They did well. But as I've been adamant about for a long time is that I really like hard cone drivers. If done right, they have a tad more micro dynamics and detail retrieval paper or composite drivers don't have.
I understand that not all people can hear does micro details and to them, it does not matter if a driver has it and that is fine. If you can't hear it, then paying for it is more or less a wast of money. Not for me, I need that extra. So I really think, no matter how good the Purifi is, for now, the SB17BNAC is probably the driver I will use.
I can always experiment with other driver combos further down the road, like the Bliesma T25D, one day I'd love to experience it, but not for this round.
While I am writing this entry, I have not heard the NBAC but I know what well designed Al drivers can do, so I am fairly confident.
Use the 4'th way to build multiple subs
This will make the bass performance much much better than possible with a standard set of speakers.Simply build your speakers 3 way and let them be able to play all the way down - no high-pass on the woofers. Then you add a minimum of two subwoofers, one next og close to one of the main speakers and then a second and preferably a third, somewhere else in the room.
Then follow this approach:
Multiple Subwoofer after Geddes
aww.... come on.... you'll love it - and you can implement it so easilyPerhaps in my second or third round
8 channels in total gives you the possibility of stereo 3-way plus DBA (Double Bass Array)...Use the 4'th way to build multiple subs
Simply build your speakers 3 way and let them be able to play all the way down - no high-pass on the woofers. Then you add a minimum of two subwoofers, one next og close to one of the main speakers and then a second and preferably a third, somewhere else in the room.
Then follow this approach:
Multiple Subwoofer after Geddes
When you clean up the bass area beneath 150hz with multi-subs - you can much better hear the upper octaves. My system is 3 way with 4 subs - it works exellent and I can clearly hear the top end, cause the bass does not mask it with to much "boom" in the sub region. Small nuances in the midrange and tweeter, will drown, if the bass is not smooth and cleanI care more about the upper octaves clarity and detail than I car about bass, but there need to be some good body in the bass region
You are 100% correct. It is also related to the transient performance of the woofer(s) and alignment. I tend to like woofers that are 6.5-10" due to them sounding less bloated than say 12-18". But that has much to do with the cabinet, if not designed properly, cab resonance is killing the details in the top end. So several small woofers is better than a single large one.When you clean up the bass area beneath 150hz with multi-subs - you can much better hear the upper octaves. My system is 3 way with 4 subs - it works exellent and I can clearly hear the top end, cause the bass does not mask it with to much "boom" in the sub region. Small nuances in the midrange and tweeter, will drown, if the bass is not smooth and clean
A single 10" is okay because its a good balance between Sd and possible transient performance. Just my 2 cents
The quality of the build does a huge difference - yesYou are 100% correct. It is also related to the transient performance of the woofer(s) and alignment. I tend to like woofers that are 6.5-10" due to them sounding less bloated than say 12-18". But that has much to do with the cabinet, if not designed properly, cab resonance is killing the details in the top end. So several small woofers is better than a single large one.
A single 10" is okay because its a good balance between Sd and possible transient performance. Just my 2 cents
Also closed subs..... no ports in any speaker for me
You have small room - you have the money - two subs would be a breeze
But I look forward to see more of the project
Closed or aperiodic is simply the way forward for transient perfect loudspeakers.
You and me both. I've been thinking and breathing audio and loudspeakers for a long time. My financial situation didn't allow me to make the moves I wanted, and perhaps that was a good thing.
I am in the middle of collecting gear or hardware which is needed before I can play on any loudspeakers, so that has to come first and it must be done well. So some time away until the loudspeakers are a real thing. I would say next spring or so.
Soon the GB of the UGS Muses (MkII) preamplifier is closed and shipping will start, looking forward to that one.
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Not to hack the thread, but did a render of my preamp versions. The buttons will not be part of the one I finally build.
You and me both. I've been thinking and breathing audio and loudspeakers for a long time. My financial situation didn't allow me to make the moves I wanted, and perhaps that was a good thing.
I am in the middle of collecting gear or hardware which is needed before I can play on any loudspeakers, so that has to come first and it must be done well. So some time away until the loudspeakers are a real thing. I would say next spring or so.
Soon the GB of the UGS Muses (MkII) preamplifier is closed and shipping will start, looking forward to that one.
-EDIT-
Not to hack the thread, but did a render of my preamp versions. The buttons will not be part of the one I finally build.
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Double Bass Arrays give the cleanest in-room bass reproduction, bar none. The whole point is bypass all room modes.You are 100% correct. It is also related to the transient performance of the woofer(s) and alignment. I tend to like woofers that are 6.5-10" due to them sounding less bloated than say 12-18". But that has much to do with the cabinet, if not designed properly, cab resonance is killing the details in the top end. So several small woofers is better than a single large one.
A single 10" is okay because its a good balance between Sd and possible transient performance. Just my 2 cents