Also notice the width of the nulls in the Directivity window. The higher ctc actually creates much narrow nulls. True it is closer to on-axis, but smaller nonetheless. So the question becomes, for critical listening, how much do those nulls aimed over youf head and at your feet really matter? More than actual first reflection from the ceiling and floor that is aimed at your head?
Again I will leave the closer driver option open to people, but then you will get marginally better-than-M126 performance, instead of much better performance. That's the idea anyway.
EDIT: the VituixCAD plots are early prototyping sims using idealized drivers.
Again I will leave the closer driver option open to people, but then you will get marginally better-than-M126 performance, instead of much better performance. That's the idea anyway.
EDIT: the VituixCAD plots are early prototyping sims using idealized drivers.
Last edited:
That's a little overdramatic! Mine is from MLCS I think. And of course you slow it down to 6-8k rpm. Cuts just fine. Just take 4+ passes and be steady and slow.
This is the ceiling bounce as defined by CEA2034, 40-60 degrees, you won't find this on a typical TM (at the average 50 degrees the response is basically flat - almost like a coincident driver!):
Basically you get better on-axis and first reflections, at the expense of a narrower vertical sweet spot. I assumed March Audio and Buchardt were forced into this ctc distance given their circular waveguides, but the when you see their crossover points of 2.4-2.5khz, I think they are optimizing in the same way I am. It's been a hard perspective change for me, but listening to two prototypes the other day with the two different ctcs seemed to confirm the improved measurements are worth it for critical listening. If someone really needs the closer spacing for casual listening laying on the couch, I'm going to include an option to move the woofer up.
I should add the above is with an 8" ctc. I backed off to 7" simply out of fear I was going too far. Even though my listening tests didn't turn up any issue. So I do expect the final design may not be quite as good as the above plot, but I'll be more confident that the vertical sweet spot will not be issue for people in critical listening either.
So, if close CTC distance is not desirable, then what's the point of the elliptical waveguides?
Circular WG looks better on it's own and also on the baffle when paired with mid(woofer) and we don't need to see the (IMO) ugly unused space between the drivers if we want larger CTC distance. The dispersion of a good circular WG is also more uniform than of an elliptical.
Circular WG looks better on it's own and also on the baffle when paired with mid(woofer) and we don't need to see the (IMO) ugly unused space between the drivers if we want larger CTC distance. The dispersion of a good circular WG is also more uniform than of an elliptical.
https://www.diyaudio.com/community/threads/are-round-horns-better.340280/page-1
I found this via sear h i Hope it can Help you and i would also appreciate if some one could give his opinion on this
I found this via sear h i Hope it can Help you and i would also appreciate if some one could give his opinion on this
Last edited:
1) maximum flexibility for end users
2) some tweeters measure better on ellipticals, some on circular, so there may not be a choice
3) MTM still benefit from very close spacing
4) is uniform what we always want? Maybe some would like a bit more constrained vertical response that ellipticals provide
My guess is direct sound above the modal region is more important than most reflected sound unless the reflections are very close in time and intensity.
Nice exercise with these CTC variations...
After so much contemplation from various sides on this and other forums I guess one has to take this individually, based on room acoustics and personal preferences...which one will like in the end. It looks like not so dramatic decision in general design of a speaker beside all other aspects.
And SB 17CAC35-4 is begging to be used as pure mid in large 3 way without too much cone travel....
What I would try additionally is supressing 10 kHz resonance in some mechanical way. This is frequency of it's coil diameter (10 kHz = 34 mm wavelength) and unit is screaming in all directions here. Maybe some non invasive felt ring or dot on the dustcap would supress that peak...without killing all other parameters....?
I have to turn on my measuring gear asap...so much to do and so little time...
After so much contemplation from various sides on this and other forums I guess one has to take this individually, based on room acoustics and personal preferences...which one will like in the end. It looks like not so dramatic decision in general design of a speaker beside all other aspects.
And SB 17CAC35-4 is begging to be used as pure mid in large 3 way without too much cone travel....
What I would try additionally is supressing 10 kHz resonance in some mechanical way. This is frequency of it's coil diameter (10 kHz = 34 mm wavelength) and unit is screaming in all directions here. Maybe some non invasive felt ring or dot on the dustcap would supress that peak...without killing all other parameters....?
I have to turn on my measuring gear asap...so much to do and so little time...
And SB 17CAC35-4 is begging to be used as pure mid in large 3 way without too much cone travel....
...I have to turn on my measuring gear asap...so much to do and so little time...
Yes sir. Though as a pure mid that SB15 is arguable better. It's been done for the SB15CAC-8 and 4 (albeit without waveguides, for people who prefer wide dispersion)
WMT:
https://techtalk.parts-express.com/...ery/1428596-the-travelers-new-year-new-design
WWMTM:
https://www.diyaudio.com/community/threads/anthology-ii.401386/#post-7408616
It's also been turned into a coincident/coaxial using the cone as a waveguide for the tweeter:
http://5een.co.uk/SB17Coax.htm
Last edited:
Could you write a few words about your listening test? Room, distance, how to switch, low frequency extension and your impressions?
Do you have a pic of the prototypes? (It's always nice to see how other people tinker
- my prototypes range from cardboard to nicely painted)I have absorption on all my ceilings where I do my usual listening tests ... maybe that's one of the reasons I prefer a small distance
Let's find a more typical room ... (the part of my living room whare the home cinema sits also get's an absorbant ceiling of course)