Hello everyone!
After recently completing a pair of 2-way Synergy-style horns, I've come to the realisation that a point source design forever needs to remain in my future
While I'm in-between projects, I started reading around, and ended up on the subject of Coaxial drivers. Considering that there are studio monitors out there (e.g. Tannoy designs from the 1970s), I can't help but think it's a technology I should explore.
The main reasons for this are:
Is it currently feasible to use a coaxial driver to cover, say, 150Hz to 20kHz?
Listening distance from the speakers would probably be around 10-12 feet.
What drivers do people recommend nowadays? My current readings on this forum seem to point towards BMS and B&C as good options, but I'd like to hear from the experts as to what your thoughts are!
Thanks!
After recently completing a pair of 2-way Synergy-style horns, I've come to the realisation that a point source design forever needs to remain in my future
While I'm in-between projects, I started reading around, and ended up on the subject of Coaxial drivers. Considering that there are studio monitors out there (e.g. Tannoy designs from the 1970s), I can't help but think it's a technology I should explore.
The main reasons for this are:
- A point-source is possible because of the physical arrangement of the LF and HF drivers
- Building an enclosure for a driver does not appear to be that complicated
- Building a crossover hopefully won't be too difficult as well, just mainly compensating for the increased sensitivity provided by the compression driver
Is it currently feasible to use a coaxial driver to cover, say, 150Hz to 20kHz?
Listening distance from the speakers would probably be around 10-12 feet.
What drivers do people recommend nowadays? My current readings on this forum seem to point towards BMS and B&C as good options, but I'd like to hear from the experts as to what your thoughts are!
Thanks!
Coaxials are lots of fun you are in for a threat. I’m not saying they have a perfect flat frequency but to me the gains of a high sensitive point source is worth it. Coaxials comes in all sizes and shapes (and prices) - do you have budget or a size preference? To me it starts to be interesting at 10 and 12 inches. Some have a short tweeter horn covered by the bass dust cap while other have a larger open horn that covers parts of the bass membrane used for larger arenas. Most have a shared magnet and some with neo magnets to reduce weight while others have a detachable screw-on compression driver with its own magnet and longer throat. BMS, B&C, Beyma, Faital all have many but they cost - beware that most are PA style drivers but there is no reason to be skeptical. Some cheaper alternatives are Eminence and Celestion which I’m currently exploring with good results. I’m not expert and I realized I’m not so picky, and I know not all like the sound of a large coax, especially the higher midrange seems to be a problem for many. But it’s fun and worth a try
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150Hz-20kHz is easily achieved. I use a pair of Faital Pro 10HX230 for PA duties, usually >100Hz with a subwoofer, but they'll get to 70Hz without. They sound great once the crossover and/or processing is dialled in, and get very loud for a relatively small box.
Chris
SB Acoustics makes three coaxial drivers and has suggested crossovers for use with them. At least with their drivers, a crossover is needed to contour the sound: it's not just for level matching.
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/sbacoustics/SB-PFC-COAX_Crossover.pdf
Geoff
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/sbacoustics/SB-PFC-COAX_Crossover.pdf
Geoff
i like coaxials too but i have only worked with a few, some car audio coaxials, in-ceilings, seas t18, sb16, p-audio sn6-150cx, eminence 12cx
in some ways they are ideal to work with but also very difficult, to get very smooth frequency responses that most builders seems to have as primary target is almost impossible
but if one choose the right coaxial driver with good on and off axis behavior you will most likely end up with a very good loudspeaker
in some ways they are ideal to work with but also very difficult, to get very smooth frequency responses that most builders seems to have as primary target is almost impossible
but if one choose the right coaxial driver with good on and off axis behavior you will most likely end up with a very good loudspeaker
Coaxial speakers can be "synergized" as well - but t hat requires 3D printing or CNC machining. I have a pair of BMS 5C150s in my shopping basket for a project like that.
I really like my Beyma 12XA30NDs in small cube boxes. They are quite smooth and well behaved with the factory passive crossover. Some more info here Compact PA - in a car handled by a single man.
I really like my Beyma 12XA30NDs in small cube boxes. They are quite smooth and well behaved with the factory passive crossover. Some more info here Compact PA - in a car handled by a single man.
I think that's the direction I'm heading in too, though if an 8 inch driver provides all I need then I'm willing to be persuaded
I'm not sure if this is a common thing, but I really do like the sound of the mids coming from a larger driver. As a Bass player, I've always favoured a 1x15" cabinet over something like a 4x10". There's this warmth that I miss with smaller drivers.
However, that's at stage sound levels. My primary focus for this thread is for indoor listening, mixing and recording.
Please keep us posted with your experiments on the Eminence and Celestion drivers! From the reviews I've read they don't seem to be aimed for home/HT use, but if they can be made to work with relatively little fuss, that's a huge plus!
Thanks Chris! Yes, I'll be able to run them with subs, so I have that benefit of not aiming for the low end
Thanks Geoff! I get the impression that the manufacturers like this build coaxials because they care about the benefits of the design. It definitely gives me something to read about in the evenings!
Thanks celef for your experience on this! What ways have you found to reduce the frequency response issues?
Those PA speakers look fantastic, and given the size I hope they allow you to set things up relatively quickly
When you're referring to synergizing coaxial drivers, how is that done? Is the coaxial driver placed at the throat/apex of the horn, and then you have standard midbass woofers fire in from the sides? It almost seems like a synergy horn could be a larger multi-driver version of a coaxial speaker in itself
Thanks for all of your responses so far - this is turning out to be a very interesting thread, and I've got lots of homework to do!
The broadcast, recording/studio monitor 'standard' for much of its early '40s to date legacy: http://greatplainsaudio.com/wp-content/uploads/2016/06/604_8H_III.pdf
Or better yet, it's updated original AlNiCo version: http://greatplainsaudio.com/wp-content/uploads/2020/604E/604E_Series_II.pdf
There is a coaxial driver at the apex of the horn, but the throat is coupled only to the HF driver horn. That is why there should be no dustcap. The cone portion of the coaxial is lead through a chamber and ports to a point down the horn. For example, the Danley signature or their smaller speakers use coaxial drivers this way. Or aragorus is describing his own here: Bookshelf Synergy with a 6.5" Coax in a reflex box
You can read about my ongoing current and upcoming coax projects in the links below, as you can see I suffer an obsession.
It’s a long way to go still but I just love the way these speakers make me feel like I’m at a concert or in the club, especially the 12” drivers have that feel I look for.
How bout trying the Celestion 15” or maybe the new Eminence Kappalite coaxials? The later 12” is on my next project list
If you can go active\DSP then you will be able to sort out most problems easily.
Eminence Beta 10cx pine build
Eminence Beta 12CX/ASD1001 coaxial upgrade modification options?
Eminence Kappalite Coaxials - another 12" two-way coax monitor project?
Yet another large coax build Celestion FTX1225 (ongoing, advice needed)
Erich just listed the Vortex12 kits for US$ 220 a side, minus crossover parts. Available at diysoundgroup. The 15's are listed as out of stock, but if you contact him, he may have the coax and compression drivers. I picked up a pair of the 15's, and the boxes are almost done, so I can't speak to how they sound yet, but the Kappalite based driver is well built, and very light with the neo magnet. Glenn.
Well, if you can drool over anything, GPA drivers would be it! I would love to hear a pair of these! Sadly, they're out of my budget
How do they compare to the Tannoy Gold drivers (or the drivers Tannoy used in the Cheviot cabinet)?Fascinating, and it makes complete sense, leading to a rather compact Synergy horn! I can see why 3D printing or CNC milling would be the optimal route, but it does make me wonder what could be done by hand...
I suppose you're essentially re-converging the output between the two drivers, which might give rise to certain time/phase-related issues. I'll have to re-check the thread, but I wonder what aragorus thinks of loading the speaker into a Synergy configuration compared to how the driver is when mounted in a standard enclosure.
You can read about my ongoing current and upcoming coax projects in the links below, as you can see I suffer an obsession.
It’s a long way to go still but I just love the way these speakers make me feel like I’m at a concert or in the club, especially the 12” drivers have that feel I look for.
How bout trying the Celestion 15” or maybe the new Eminence Kappalite coaxials? The later 12” is on my next project list
If you can go active\DSP then you will be able to sort out most problems easily.
Eminence Beta 10cx pine build
Eminence Beta 12CX/ASD1001 coaxial upgrade modification options?
Eminence Kappalite Coaxials - another 12" two-way coax monitor project?
Yet another large coax build Celestion FTX1225 (ongoing, advice needed)
That's a good obsession to have! Which of those projects is your favourite in terms of sound?
Gravitating towards a 15" driver would be what I'd want to do, but given their prices I'd have to make sure that there's a solid design out there that I could build with normal workshop tools.
Well the Celestion 12" in a 60l box sounds the "best" so far but I haven't really tested all that much yet any of the builds, no measurements or anything just subjective observations.
If its due to better driver or a better/bigger box I am not sure, its still early in my testing.
But all the drivers sounds pretty good in my opinion for the sound I'm looking for.
I also use stock crossovers so its more luck than anything scientific.
All of the ones Ive tested I consider budget solutions with a lot of give and take, you want get it all. With higher priced coaxials maybe more could be gained, thats why Im considering the Kappalites for my next project however at that price there is a lot of other options.
I start to realize I need sub for all of them though.
Much like any PA midbass.
If its due to better driver or a better/bigger box I am not sure, its still early in my testing.
But all the drivers sounds pretty good in my opinion for the sound I'm looking for.
I also use stock crossovers so its more luck than anything scientific.
All of the ones Ive tested I consider budget solutions with a lot of give and take, you want get it all. With higher priced coaxials maybe more could be gained, thats why Im considering the Kappalites for my next project however at that price there is a lot of other options.
I start to realize I need sub for all of them though.
Much like any PA midbass.
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I'm happy to. I'll try to do that tomorrow after work. The Denovo version has a custom machined horn and curvilinear cone that is not the same as the Kappalite Eminence version. These were designed to be better for hifi vs. PA usage, buy they share the basket. Glenn.
I think the main point in synergizing a coax is in horn loading and also directivity control. It definitely brings some challenges for the design and tuning, but I bet with a DSP the result will be superior to a standard box.
By the way, I also really like coaxials - this was one of my first speaker projects finished, my brother still uses them: Eminence Beta 12 CX + Selenium D210Ti MLTL (huge)
And I have a pair of KEF iQ3s I bought second hand for rebuild and experiments. They work so nicely as PC speakers that I have not touched them yet. And my boss uses KEF X300A as his PC speakers and these are just wonderful.
Actually, what hooked me up to coaxials was hearing Tannoy DC studio monitors while recording some songs in a studio many years ago. Later, I was bitten by the horn bug and cannot live without horns anymore
By the way, I also really like coaxials - this was one of my first speaker projects finished, my brother still uses them: Eminence Beta 12 CX + Selenium D210Ti MLTL (huge)
And I have a pair of KEF iQ3s I bought second hand for rebuild and experiments. They work so nicely as PC speakers that I have not touched them yet. And my boss uses KEF X300A as his PC speakers and these are just wonderful.
Actually, what hooked me up to coaxials was hearing Tannoy DC studio monitors while recording some songs in a studio many years ago. Later, I was bitten by the horn bug and cannot live without horns anymore
You are increasing the compression ratio at least, fwiw. Directivity would be a bit of a speculation.
Thanks Glenn. That'll be interesting to see. While I've been looking around at coaxial designs, the 'single unit in a box' feels like we're cheating physics or something
Then again, all of the hard work is going into the drivers themselves, seemingly subtracting complexity from the enclosures.I think a DSP would be fine for most cases. Personally I'd probably make an attempt at smoothing the reponse with an analogue crossover/attentuation circuit to keep the latency in the signal path low (for those times when I want to monitor the music I'm recording to without headphones).
Actually, what hooked me up to coaxials was hearing Tannoy DC studio monitors while recording some songs in a studio many years ago. Later, I was bitten by the horn bug and cannot live without horns anymore
I remember my grandfather bringing me a couple of car speakers when I was a kid, and I was impressed by 'the coaxial one'. I've heard them in studios too, and there definitely is something about them that works!
Thanks to diyaudio, I've been fiddling around with horns for the last 8 or 9 years or so, and I must admit I've fallen for them too.
I wonder if, rather than putting the driver behind a Synergy design, we treat the coaxial driver itself as the first stage of a horn. Maybe all we'd need for the desired effect is to create a second flare that begins where the woofer cone ends?
Well, if you can drool over anything, GPA drivers would be it! I would love to hear a pair of these! Sadly, they're out of my budget
Mine too nowadays.
No clue; I assume there were some folks in the metro Atlanta area with Tannoys way back when, but didn't know of any till circa 2008, several decades past my association with 604s, so memory much too dim to comment and can't remember the Tannoy model I did audition except it was in a relatively small [by my standards] BR.
The home synergy may not need to be the same as the pro synergy, perhaps I'm the one just speculating. When a horn is used across the loading transition it doesn't cause a problem that I've noticed.
Because the cone will dictate a wider waveguide.
Also, you'll want to cross low enough that the woofer section doesn't get more narrow than that, but you'd normally do that anyway.
Because the cone will dictate a wider waveguide.
Also, you'll want to cross low enough that the woofer section doesn't get more narrow than that, but you'd normally do that anyway.