I like the way you qualify your answers - that's the card I usually play
Haha you might just be a millennial then!
Does anyone understand line-array theory? I'm trying to grasp the theory but there isn't much layman's information out there.
I did some math on center-to-center driver spacing. Foam core could be as close as ~3.9", and ~4.5" using 3/4 MDF or Birch Plywood. Line length for the radiating area of two TC9FD's is ~6.52".
From what I understand, 2 TC9FD drivers do not fill both requirements for line sources at any frequency. Am I wrong?
I found this website.
Learn some basic Line Array design theory
"An accepted approximation is that the source centres need to be less than ½ a wavelength apart... The source needs to be at least four times as long as the wavelength. "
Learn some basic Line Array design theory
"An accepted approximation is that the source centres need to be less than ½ a wavelength apart... The source needs to be at least four times as long as the wavelength. "
I did some math on center-to-center driver spacing. Foam core could be as close as ~3.9", and ~4.5" using 3/4 MDF or Birch Plywood. Line length for the radiating area of two TC9FD's is ~6.52".
From what I understand, 2 TC9FD drivers do not fill both requirements for line sources at any frequency. Am I wrong?
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kudos to xrk971, he clued me in to this thread.
I'm repeating myself here, because I mentioned this in another thread, but here's some random observations:
1) I heard these at CES in 2016, and if you had a blindfold on, you *would* think these are $5000 speakers. They sound really nice. I'd rate them as better than 90% of what I heard at CES.
2) I took some pictures up close. I believe the woofers are Tymphany TC9, and the subwoofer is a Dayton Reference 8" subwoofer. Yes, it looks like everything you need to build this setup is from Parts Express.
3) My only real complaint with the speakers is that they had them *really* far from the walls. That allowed them to image like crazy, but I also heard a touch of harmonic distortion. Not a lot, if anything the distortion may have been adding some euphonic glow to the sound. (Carl was using tube amps.)
To me, the most interesting part about this design is that it bested some of his other designs. Which are way, way more expensive and complex. Here's my hunch: In the other Nola speakers, the designer sometimes have to resort to horizontal arrays. And we've all seen the polar response on horizontal arrays, it's pretty bad. So I think the designer hit a 'sweet spot', where the TC9 has wide enough bandwidth that we can basically get away with using it as a tweeter.
Here's one of Carl's designs, to illustrate what I mean in the previous paragraph
I've built my own 'homage' to the Linkwitz dipole, and I think Carl's design sounds better than mine.
But definitely highly recommended! As far as cardioids go, I think the Gradient Helsinki is still the best I've heard, but for a fraction of the price, Carl's design is awesome.
I'm repeating myself here, because I mentioned this in another thread, but here's some random observations:
1) I heard these at CES in 2016, and if you had a blindfold on, you *would* think these are $5000 speakers. They sound really nice. I'd rate them as better than 90% of what I heard at CES.
2) I took some pictures up close. I believe the woofers are Tymphany TC9, and the subwoofer is a Dayton Reference 8" subwoofer. Yes, it looks like everything you need to build this setup is from Parts Express.
3) My only real complaint with the speakers is that they had them *really* far from the walls. That allowed them to image like crazy, but I also heard a touch of harmonic distortion. Not a lot, if anything the distortion may have been adding some euphonic glow to the sound. (Carl was using tube amps.)
To me, the most interesting part about this design is that it bested some of his other designs. Which are way, way more expensive and complex. Here's my hunch: In the other Nola speakers, the designer sometimes have to resort to horizontal arrays. And we've all seen the polar response on horizontal arrays, it's pretty bad. So I think the designer hit a 'sweet spot', where the TC9 has wide enough bandwidth that we can basically get away with using it as a tweeter.
Here's one of Carl's designs, to illustrate what I mean in the previous paragraph
I've built my own 'homage' to the Linkwitz dipole, and I think Carl's design sounds better than mine.
But definitely highly recommended! As far as cardioids go, I think the Gradient Helsinki is still the best I've heard, but for a fraction of the price, Carl's design is awesome.
One of the most informative sources of info on line arrays would be James R. Griffin's paper: http://www.audioroundtable.com/misc/nflawp.pdf
Then there's David L. Smith who, when he was working at McIntosh, published a lot of info on arrays. Let me get the right post: http://www.diyaudio.com/forums/multi-way/165596-constant-beam-width-transducers-line-arrays-6.html#post2257395
I've also done some experiments myself and have a different look at some parts of the theory. I understand where the 1/2 wave center to center spacing theory comes from but I rather look at the distance from source driver to your ear at the listening spot.
If you would mount your drivers on a focussed arc/array, you would not get any combing of high frequencies in the exact listening spot. Bend them the other way and you're in Don Keele's territory. (even he was/is a member here but doesn't seem to post that much anymore)
Luckily the first 2 are active members here and have much more to share if you look for it. I linked all of the user profiles so interested parties may look up their posts.
For this case, I wouldn't call 2 speakers close to each other anything resembling a line array or having line array behaviour. You might get some type of cardioid action somewhere though, with the back wave and some of the monopole output cancelling each other out at the back. But line array? Neh...
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Nice catch! I didn't notice that about the design. Seems it's a core part of the designers design theory. If you pay close attention the "top" of the ported enclosure on the bottom- its slightly slanted. At first I thought this was only to reduce diffraction inside the enclosure, but it also prevents standing waves between the top of the speaker and the top of the ported enclosure. Pretty smart!
I'm guessing it's also part aesthetics, but also I think it could reduce reflections to the ceiling. I theorize that it also increases the baffle "length", although I'm not sure if it would actually have a measurable effect.
I gotta say, I underestimated how polished and in many ways innovative the Trios' are. I haven't seen a product which doesn't just trade performance for aesthetics- but actually enhances performance with aesthetically pleasing concepts. I know for a fact Carl (Trios designer & I believe owner of NOLA) browses these forums. Choosing the TC9FD by sheer luck would be a hell of a circumstance.
Would the single cap be to flatten out the dipole peak (so it crosses above the peak in frequency) instead of having the objective to prevent the driver from bottoming out?
A view all around and a talk with the designer: https://www.youtube.com/watch?v=XdHzfGfVjbw
A view all around and a talk with the designer: https://www.youtube.com/watch?v=XdHzfGfVjbw
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I've been kicking around the idea of a Nola type speaker for quite a while now. It's all started with Wesayso's line array build combined with my appreciation for OB. I've acquired over 60 TC9s now to do a line array OB/sealed configuration. Top 8 drivers and bottom 8 drivers sealed with 12 OB in the center of the array. Was gonna do something similar to Wesayso but couldn't get my mind arrayed way from OB and couldn't wrap my mind around the laminate style enclosure. I know it's a bit of a departure from the Trio Brio but maybe I'm on to something.
Wes
Wes
Yes, that is the speaker I'm describing.
Carl has always had speakers that sounded special, but this is the first one that really knocked it out of the park for me. I think the elimination of the horizontal array is a smart move.
I think this is for cosmetic reasons. When the grill cloth is put in place, it looks like a conventional speaker.
If you look at the top, sides, and back, they're open. But there's a frame there.
This 'trick' was pioneered by Vandersteen. It may not be obvious in the pic, but the top is open, along with the sides.
BTW, don't google "naked vandersteens" at work
EDIT : I was wrong about the top, but I think I'm right about the sides, this is just cosmetic.
BTW, looks like you can get the plate amp at PE too
http://www.parts-express.com/dayton-audio-spa250-250-watt-subwoofer-plate-amplifier--300-803
An externally hosted image should be here but it was not working when we last tested it.
^^ PE SPA 250
An externally hosted image should be here but it was not working when we last tested it.
^^ Nola Brio Trio
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The interview that Wesayso posted has all the info you need to build these. But I'm trying to wrap my brain around how this thing will radiate.
Both drivers are run in parallel, but only the top is highpassed. This means that at most frequencies, the speaker will have a cardioid response. (Sealed + dipole = cardioid.) But at low frequencies, it's going to be a monopole, because the upper driver is rolled off. Instinctively, it seems like this type of radiation pattern would sound "thin" because we have TWO drivers running over most of the spectrum, but only one at low frequencies.
If I had to speculate here, I'm guessing that the 'secret' sauce may be an overlap from the "subwoofer" to the satellites. IE, by overlapping the output from the sub to the satellite, you could have multiple sources covering half an octave from 125hz to 200hz. IE, output from the "subwoofer" could augment the output from the driver that's being highpassed.
Another possibility is that running two drivers doesn't make the speaker sound 'thin' because the two drivers are in a cardioid configuration. Anyone who's messed around with dipoles or cardioids has certainly noticed that they don't interact with the room the same way that monopoles do.
Some simulations are definitely in order! I have a feeling that the 'trick' here is a fair amount of trial and error with the lowpass setting on the sub and the high pass on the dipole element.
Both drivers are run in parallel, but only the top is highpassed. This means that at most frequencies, the speaker will have a cardioid response. (Sealed + dipole = cardioid.) But at low frequencies, it's going to be a monopole, because the upper driver is rolled off. Instinctively, it seems like this type of radiation pattern would sound "thin" because we have TWO drivers running over most of the spectrum, but only one at low frequencies.
If I had to speculate here, I'm guessing that the 'secret' sauce may be an overlap from the "subwoofer" to the satellites. IE, by overlapping the output from the sub to the satellite, you could have multiple sources covering half an octave from 125hz to 200hz. IE, output from the "subwoofer" could augment the output from the driver that's being highpassed.
Another possibility is that running two drivers doesn't make the speaker sound 'thin' because the two drivers are in a cardioid configuration. Anyone who's messed around with dipoles or cardioids has certainly noticed that they don't interact with the room the same way that monopoles do.
Some simulations are definitely in order! I have a feeling that the 'trick' here is a fair amount of trial and error with the lowpass setting on the sub and the high pass on the dipole element.
No delay needed when we are talking about 80hz and down. Most humans can't localize sounds below 80hz. I've seen a few people claim that they can still kind of localize until 50hz, but honestly I think that's bull.. The wavelengths are gigantic already at 80hz.
Remember- all ported enclosures introduce delay- called group delay! With subs nobody really cares, because to my understanding it's an inaudible measurement below 80hz.
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The amp they use from Parts Express has a 220uf cap highpassing the satellites at 180Hz. The Xover for the sub on the amp goes from 40 to 180Hz. It all depends on how they wired the system.
Also, I guess that's why in the demo video for the review, they used stereo subs.
On another note, I added a small "roof" on my makeshift TC9 open baffle, and that took care of Dire Straits playing in a cavern kind of sound. I had it open on all right/left and top before. Now, with a flap on the top to limit the bleed going to the ceiling, I lost a bit of 3D spatialisation, but it also sounds more natural.
BTW, Xaborus, you either work the night shift, or don't like to sleep, if you are indeed from the US!
Also, I guess that's why in the demo video for the review, they used stereo subs.
On another note, I added a small "roof" on my makeshift TC9 open baffle, and that took care of Dire Straits playing in a cavern kind of sound. I had it open on all right/left and top before. Now, with a flap on the top to limit the bleed going to the ceiling, I lost a bit of 3D spatialisation, but it also sounds more natural.
BTW, Xaborus, you either work the night shift, or don't like to sleep, if you are indeed from the US!
Holey *^%%.
That's going to be huge! A hell of a build indeed. Goodluck! You're braver than I am. I was thinking along those lines too Patrick. I think percevals' find about the subwoofer hi-passing the satellites shows that this is a good possibility. I was curious why they setup the single subwoofer in the middle of the room- makes sense if you have 180hz coming out from it. Hi-passing 180hz to the satellites Is really going to improve power handling to them too.
Perceval, it's a combination of unemployment and insomnia lol. Thankfully the wife agreed to buy me 4 TC9FD's as an early Christmas present.
Edit: This reminds me that I came across a discussion somewhere that vinyl sounds different/warmer because the bass has to be summed to mono. Trying to find this discussion, I came across an article for clubs/studios producing electronic music which recommended mono bass under 80hz to decrease desconstructive interference present in stereo bass. No idea what frequency cut off is usually used in vinyl to sum to mono. Kind of interesting though.
Edit 2: Found discussion among those who create music on gearslutz that it's not uncommon to sum bass to mono around and under 150-200hz on Vinyl. Pretty interesting!
Perceval, it's a combination of unemployment and insomnia lol. Thankfully the wife agreed to buy me 4 TC9FD's as an early Christmas present
.Edit: This reminds me that I came across a discussion somewhere that vinyl sounds different/warmer because the bass has to be summed to mono. Trying to find this discussion, I came across an article for clubs/studios producing electronic music which recommended mono bass under 80hz to decrease desconstructive interference present in stereo bass. No idea what frequency cut off is usually used in vinyl to sum to mono. Kind of interesting though.
Edit 2: Found discussion among those who create music on gearslutz that it's not uncommon to sum bass to mono around and under 150-200hz on Vinyl. Pretty interesting!
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Well, Wes...
I wish you all the best in your endeavour!
You know, I think you will achieve with your OB drivers in the middle, what wesayso does using JRiver and his mid/side processing.