Hestia OB, an ambitious low cost, 3-way OB design

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matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #300 on: 2 Dec 2018, 07:59 pm »
FaitalPro HF-102. It’s about 95dB @ 20kHz, 1w/1m. It’s compression but sounds like a quality dome tweeter on steroids.

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #301 on: 5 Dec 2018, 04:45 pm »
FaitalPro HF-102. It’s about 95dB @ 20kHz, 1w/1m. It’s compression but sounds like a quality dome tweeter on steroids.

That's a company I have not come across before. They do a bewildering amount of 1" drivers. How on earth do you chose? In addition I have always assumed that compression drivers need a horn. Am I wrong?

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #302 on: 5 Dec 2018, 05:23 pm »
You probably want to use a short-throw horn or no horn at all, depending on your ceiling height. It's best to keep the dispersion fairly narrow when reflecting off the ceiling for ambient fill. The highest frequencies will radiate into the room the same way a cymbal disperses energy. I have found the rules for ambient tweeter setup to be different from everything else. Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.   

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #303 on: 5 Dec 2018, 05:39 pm »
You probably want to use a short-throw horn or no horn at all, depending on your ceiling height. It's best to keep the dispersion fairly narrow when reflecting off the ceiling for ambient fill. The highest frequencies will radiate into the room the same way a cymbal disperses energy. I have found the rules for ambient tweeter setup to be different from everything else. Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.   

Thanks, I assume without the horn loading the 107dB sensitivity will be very much reduced, which is good as my mid range driver is 95dB. This may avoid the need to put a horrible volume control on the tweeter.

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #304 on: 5 Dec 2018, 08:36 pm »
With a small value cap (0.15uf - 0.22 uf) you likely won't need to worry about attenuating the horn driver to match other drivers. What comes through are mostly high register reflections and other spatial queues. An interesting test is to sit in the listening position and have someone connect and disconnect the driver to better appreciate the effect. It's not insignificant, yet if you listened to the driver on its own, you would likely not be impressed.   

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #305 on: 6 Dec 2018, 08:27 am »
Try crossing high with a single cap; I am using a 0.15uf Mundorf Supreme with my FaitalPro HF-102. It has a big impact on my front firing full ranger and is quite seamless.   

Sorry to be a nuisance, but there are lots of caps under the Supreme banner. Which one are you using?

https://www.hificollective.co.uk/components/m_cap.html

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #306 on: 6 Dec 2018, 10:36 am »
Sorry, I’m actually using a Jantzen Z Silver cap with the HF-102’s. It’s a 0.15 uF value. I preferred this to the Mundorf cap that I had on hand, when coupled with the compression drivers.

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #307 on: 7 Dec 2018, 04:49 pm »
Hi Matevana

I am about to order a pair of these drivers, but remain intrigued as to how you came to discover that a professional compression driver could make a good job as an ambient 'super' tweeter. Up until this point I had never come across this Italian brand for Hi Fi.

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #308 on: 7 Dec 2018, 06:20 pm »
Since I was only interested in reproducing the highest audible reflections, I needed a driver that would play fairly loud in the 15-20kHz range. Most drivers are rated for loudness using a weighted average, so even if you were to find a dome tweeter with an average SPL of 95dB, it might be as much as 10dB lower in the 15-20kHz range. Pro sound drivers however routinely produce higher SPLs across their usable spectrum, so it's just a matter of finding one that plays loud enough approaching 20kHz. While many pro sound drivers may not be considered "hi fi", several non titanium diaphragm drivers come close. I would consider some of the FaitalPro drivers to fall in that category.

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #309 on: 7 Dec 2018, 06:33 pm »
Thanks again M. I will put any updates on my own thread to save high jacking this one completely. Sorry to other readers :)

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #310 on: 7 Dec 2018, 06:59 pm »
No worries. If the information is useful to others, it's a good thing!

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #311 on: 13 Dec 2018, 03:37 pm »
Sorry, I’m actually using a Jantzen Z Silver cap with the HF-102’s. It’s a 0.15 uF value. I preferred this to the Mundorf cap that I had on hand, when coupled with the compression drivers.

Hi Matevana

Just running the capacitor values through the on line calculator - are you sure that's not 1.5uF rather than 0.15 as you recommend.  :dunno:

I make it that a 2.2uf capacitor would give a cut off of 9Kz in an 8ohm tweeter, which seems about right.

Thanks Chris

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #312 on: 13 Dec 2018, 04:04 pm »
A first order electrical crossover (1 capacitor) has a very shallow slope. If you go with a 2.2 uF cap it will attenuate only 3dB at 4500Hz, 6dB at 2250Hz, etc. If you plan to use the compression drivers as a super tweeter, you will likely want a cap with a much smaller value, or use a steeper slope (2nd, 3rd or 4th order crossover).

In my setup, (Jordan & Markaudio full range drivers) I've had good luck with a 0.15 uF cap on the FaitalPro driver.  My goal was to not draw attention to the compression driver, have it augment the highest octaves only, and not detract from the full range drivers.  I got lucky b/c the combined sensitivity of the full range drivers was a close level match with the FaitalPro's output above 15kHz so it didn't require any attenuation (l-pad). In my experience, you should barely hear any additional level gain from the output of a super tweeter when it is properly implemented.     

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #313 on: 13 Dec 2018, 06:01 pm »
Thanks again Matevana. My aims are the same as yours and your knowledge is much greater. I will go with that   :thumb: :thumb:

Poultrygeist

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #314 on: 13 Dec 2018, 08:40 pm »
Finding the right value cap for my tweeters is an exercise in trial and error. Alligator clips and listening to a variety of caps takes time but it's worth it.
« Last Edit: 14 Dec 2018, 11:39 am by Poultrygeist »

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #315 on: 13 Dec 2018, 08:49 pm »
Finding the right value cap for my tweeters is an exercise in trial and error. Alligator clips and listening to a variety of caps takes so time but it's worth it.

100%

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #316 on: 13 Dec 2018, 11:05 pm »
Thanks again Matevana. My aims are the same as yours and your knowledge is much greater. I will go with that   :thumb: :thumb:

Hey Chris,

One thing you might try per Poultry’s suggestion is to buy a bunch of cheap caps between 0.15 and 1.0 uF and do some testing yourself.  Once you have your drivers dialed-in, then go order a more expensive premium cap. Many of the small value non polarized caps are under a buck. 

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #317 on: 14 Dec 2018, 09:08 am »
Thanks guys, my current 'stock' of capacitors starts at 1uF and goes upwards, so its back on e bay for some caps for the experiments.  :D

Bumpy

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Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #318 on: 14 Dec 2018, 12:32 pm »
Hey Chris,

One thing you might try per Poultry’s suggestion is to buy a bunch of cheap caps between 0.15 and 1.0 uF and do some testing yourself.  Once you have your drivers dialed-in, then go order a more expensive premium cap. Many of the small value non polarized caps are under a buck.

Continual apologies for my ignorance, but are ceramic caps OK for crossovers. They are cheap and plentiful but I'm not sure I've seen them employed there.

matevana

Re: Hestia OB, an ambitious low cost, 3-way OB design
« Reply #319 on: 14 Dec 2018, 12:47 pm »
I've never used them in crossovers since they are usually intended for low power ICs. I'd suggest the cheapest poly caps you can find for testing. Parts Express has the Dayton brand which work well and aren't expensive. You can try 0.15, 0.22, 0.38, 0.47, and 0.68 uF values. You may find you only need 1 each for testing (mono), but up to you. Combining two caps in parallel will increase capacitance (just add the two values together) so the above caps can yield many different values in combination. A set of alligator clips also comes in handy while testing.