While the vertical beamwidth of the Beyma is not "twenty degrees" like the spec sheet promises, even sixty degrees of beamwidth will make it way easier to get away with spacing of one wavelength.
Take a look at the spec sheet of a dome:
SB Acoustics SB26ADC-C000-4 Aluminum Dome Tweeter
1) the Beyma will be 6db down at 30 degrees off axis (because it has 60 degrees of vertical beamwidth)
2) the dome will be down 0dB at 30 degrees off axis
So the ribbon allows for wider spacing.
Of course, you could simply put the dome in a waveguide...
The thing I'd really want to see is the output of the ribbon at 90 degrees off axis, because THAT is the lobe that's really nasty with one wavelength spacing
Take a look at the spec sheet of a dome:
SB Acoustics SB26ADC-C000-4 Aluminum Dome Tweeter
1) the Beyma will be 6db down at 30 degrees off axis (because it has 60 degrees of vertical beamwidth)
2) the dome will be down 0dB at 30 degrees off axis
So the ribbon allows for wider spacing.
Of course, you could simply put the dome in a waveguide...
The thing I'd really want to see is the output of the ribbon at 90 degrees off axis, because THAT is the lobe that's really nasty with one wavelength spacing
Proper c-c for almost any concept is from 1 x wave length to 1.4 x wave length at crossover frequency assuming phase match and that max. 1/4 wave length is never possible with MT. Good initial/design value is 1.2 x wave length at XO.
So the worst case scenario is 0.5-0.7 x wave length at XO.
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Quarter wavelength.
Wavelength is tossed around sinxce proper spacing with a tweeter is almost impossible.
dave
Agreed. Anything lower than 1.5-1.8Khz is asking for audible distortion from the TPL150. Anyone running it lower, has no idea what distortion sounds like or likes that "forward", in your face mid-range. We ultimately ended up at 1.5Khz crossed to the TD12M and are still not totally happy with it, but could not justify a three system at the time. TD12M are in a .5 way alignment, with only one of them playing up 1.5KHz. It's still better clarity and imaging than the majority of main monitors I've ever heard though. Just at high levels, with brass and sax's especially, you can hear the TPL150 struggling.
Scroll to bottom of page for photo.
http://phatplanetstudios.com/gear/
Greg
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It's the Vapour Arcus, which is indeed 1050Hz xo. Time ago I exchanged with the designer who explained he used the TPL-150H in this design because it could get this low. Otherwise he uses other tweeters in his designs. But that is just his set of tradeoffs. I agree it's too low for the TPLs.
I haven't. FWIW, there is a long thread by angeloitacare on the TPL plus Beyma 12p80Nd where he concluded 1.6kHz was the best xo point. By the same token others tried these two speakers combined and didn't like them, but he did. That 12" in particular doesn't get too low, though. And math/models suggest xo at 1.6kHz to 12" should be trouble from the 12" beaming. But I guess the example goes to show that some people like things others don't.
18Sound sells a horn loaded AMT that uses a substantial diffraction slot to increase the SPL level at low frequency. The slot is something like 10cm deep, it's huge.
I 3D printed something akin to a clone of it.
It measured better than the one I made with no diffraction slot, but sounded noticeably "honky."
Unfortunately, there's no free lunch I guess.
AMTs are kind of a pain in the butt, it's hard to get them to play low, in my experience.
I 3D printed something akin to a clone of it.
It measured better than the one I made with no diffraction slot, but sounded noticeably "honky."
Unfortunately, there's no free lunch I guess.
AMTs are kind of a pain in the butt, it's hard to get them to play low, in my experience.
^^It wouldn't be T anymore. Anyway minimizing c-c is not always good idea. It could damage sound balance though height of listening window could be the highest with selected XO frequency.
c-c / XO frequency is one of the most significant parameter for minimizing errors in power response and early reflections RMS. Messages 2763, 2773 in VituixCAD thread explain, and 2777, 2780, 2781 are proof of concept.
c-c / XO frequency is one of the most significant parameter for minimizing errors in power response and early reflections RMS. Messages 2763, 2773 in VituixCAD thread explain, and 2777, 2780, 2781 are proof of concept.
Starting to second guess the TMW setup. I have NSW6021 for subs atm. Is a MTM the better path. I’ve seen a few setups like this with the TD12M crossed over at different points
Again:
https://www.diyaudio.com/forums/multi-way/370900-ribbon-spacing-midrange-2.html#post6617957
-with the proper design this will far exceed what you were planning..
About a 2.2 kHz crossover freq. (for mid.& tweeter).
Baffle dependent for the mid. high-pass and double woofer low-pass.
Low port tuning freq. (around 22 Hz) for the double woofer with fairly large volume. Also, the double woofers in a vertical array near the floor (..with the bottom of the bottom woofer no more than about 8" off of the floor.)
There should be plenty of gain from the woofers and the port for good low freq. output as well as having more than enough baffle-step compensation relative to a target of about 94-96 db average (depending on how you integrate the mid and the woofers relative to baffle-step loss).
-info. on the Viawave ribbon:
Viawave SRT-7 | HiFiCompass
https://www.diyaudio.com/forums/multi-way/370900-ribbon-spacing-midrange-2.html#post6617957
-with the proper design this will far exceed what you were planning..
About a 2.2 kHz crossover freq. (for mid.& tweeter).
Baffle dependent for the mid. high-pass and double woofer low-pass.
Low port tuning freq. (around 22 Hz) for the double woofer with fairly large volume. Also, the double woofers in a vertical array near the floor (..with the bottom of the bottom woofer no more than about 8" off of the floor.)
There should be plenty of gain from the woofers and the port for good low freq. output as well as having more than enough baffle-step compensation relative to a target of about 94-96 db average (depending on how you integrate the mid and the woofers relative to baffle-step loss).
-info. on the Viawave ribbon:
Viawave SRT-7 | HiFiCompass
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Can’t seem to find anyone in North America distributing the Viawave. Is it a direct order fro them. Spoke with Kartesian, eager to work with DIY which is nice.!
Direct, unless you want to go through one of the EU resellers.
I think this email is for purchase inquiry:
dialog@viawave.ru
..and this one is for info. requests from US:
vze2frh5@yahoo.com
Apparently they use Paypal.
Viawave
The owner/manufacturer/designer has participated here before.
https://www.diyaudio.com/forums/members/malinovsky-d.html
I think this email is for purchase inquiry:
dialog@viawave.ru
..and this one is for info. requests from US:
vze2frh5@yahoo.com
Apparently they use Paypal.
Viawave
The owner/manufacturer/designer has participated here before.
https://www.diyaudio.com/forums/members/malinovsky-d.html
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Thanks Scott. Roman was incredibly quick to respond, especially considering it’s Friday night. They normally sell in matched pairs, he’s inquiring about the factory making me 3 matched or if they’ll sell 3. This is for a LCR, not as concerned about center channel being different as I would having a $600 paper weight albeit a really cool paper weight.
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FWIW, I took the MTM module and placed it in a lower base such that the top end of the AMP is at ear-level when seating. Now when I stand up I'm clearly beyond the 20 degree off vertical axis and I can certainly hear the AMT loosing intensity. In the usual base, when I'm sitting down my ears are at the low end level so when I stand up I'm not above 20 degrees above vertical axis so I had not noticed it so clearly.
Nevertheless the lobbing at 1.5kHz isn't bothering me much. Still planning to make an inductor and have only one midrange playing above 800Hz or so and maybe raise the 1.5kHz. First I need to make the right speaker, though 🙂
Nevertheless the lobbing at 1.5kHz isn't bothering me much. Still planning to make an inductor and have only one midrange playing above 800Hz or so and maybe raise the 1.5kHz. First I need to make the right speaker, though 🙂
Vivawave will make a set of 3 matched Srt-7s so this is a go . Any thoughts on the spacing between the mid /tweeter and the woofers. Should I move the tweeter off center 1” or drag the mid with it as well.
Tweeter and mid placement relative to baffle is something you model. VituixCAD is the recommended program to learn, but if you just need to play with something quickly to get some idea then the "Edge" (Tolvan) is useful as a preliminary modeler.
I prefer designs that are centered (relative to the baffle) and vertically aligned myself, even if it's more difficult to achieve a nicer result with regard to baffle-gain (and loss) from diffraction.
Generally go as high (vertically) as you can with the midrange (relative to its high-pass vs the midbass), and keep the line of midbass drivers as low to the floor as possible.
Search for "floor bounce" (as well as "floor bounce calculator" in relation to your listening distance and height).
Typically you want to have a high-pass (mid) and low-pass (midbass) around 280-380 Hz.
Note: the reason I spec'ed the two mid-bass driver in parallel (2x 16 ohm parallel to 8 ohm) is that you get 3db of acoustic gain (double the drivers) and 3 db of voltage gain (depending on the amp) from the parallel 16 ohms to a net 8 ohms.
You often want as much efficiency as you can get relative to baffle-step loss. Again, search for "baffle step loss" for more info.. You can loose up to 6 db from baffle step loss (..though it's more often 5-4 db relative to floor gain). So if you want to *try* for something like a net 96db 1 watt/1 meter result you could be looking at (as much as) anywhere between 102 to 105 db for you midbass needs relative to your amplifier.
Obviously, that's not something that an 8 ohm 15" woofer is going to provide, not anywhere near that.
IF you have a smaller baffle though, AND are going with one mid., AND have that mid's high-pass at a lower freq. near 300 Hz, THEN you are going to loose a lot of output due to the required baffle-step loss compensation. At that point you could be looking at a loss in overall "efficiency" of 3-6 db (putting a 96 db mid. around 93-90 db 1 watt/1 meter), in which case the pro 15" could be fine (depending on that mid's net "efficiency"). ..and actually you could be down even further in efficiency than that depending on the mid. driver's response in its enclosure.
I prefer designs that are centered (relative to the baffle) and vertically aligned myself, even if it's more difficult to achieve a nicer result with regard to baffle-gain (and loss) from diffraction.
Generally go as high (vertically) as you can with the midrange (relative to its high-pass vs the midbass), and keep the line of midbass drivers as low to the floor as possible.
Search for "floor bounce" (as well as "floor bounce calculator" in relation to your listening distance and height).
Typically you want to have a high-pass (mid) and low-pass (midbass) around 280-380 Hz.
Note: the reason I spec'ed the two mid-bass driver in parallel (2x 16 ohm parallel to 8 ohm) is that you get 3db of acoustic gain (double the drivers) and 3 db of voltage gain (depending on the amp) from the parallel 16 ohms to a net 8 ohms.
You often want as much efficiency as you can get relative to baffle-step loss. Again, search for "baffle step loss" for more info.. You can loose up to 6 db from baffle step loss (..though it's more often 5-4 db relative to floor gain). So if you want to *try* for something like a net 96db 1 watt/1 meter result you could be looking at (as much as) anywhere between 102 to 105 db for you midbass needs relative to your amplifier.
Obviously, that's not something that an 8 ohm 15" woofer is going to provide, not anywhere near that.
IF you have a smaller baffle though, AND are going with one mid., AND have that mid's high-pass at a lower freq. near 300 Hz, THEN you are going to loose a lot of output due to the required baffle-step loss compensation. At that point you could be looking at a loss in overall "efficiency" of 3-6 db (putting a 96 db mid. around 93-90 db 1 watt/1 meter), in which case the pro 15" could be fine (depending on that mid's net "efficiency"). ..and actually you could be down even further in efficiency than that depending on the mid. driver's response in its enclosure.
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Thanks Scott. I’ve ordered the Lom165’s and 12 PR320 as well. The build will go on as you suggested. Realistically a month minimum on the Srt7, they said to expect it to sit a customs for up to 30 days once it hit the states. Could be end of June delivery which gives me time to get this figured out, with help I’m sure. Thanks again for helping.