Here are few photos, the "head" is made from 2 bamboo panels glued together, passive crossover is in a box behind/under the B102.
Under are 2 H-Frame boxes, open front & back, with Marshall Salt & Pepper grill cloth to hide 30cm speakers, and a bit of visaton damping material at the back (it reduces fs a bit).
Head panel is inspired by Hestia V/LX 521/Orion, but was designed after few iterations/measurements.
B102 is mounted on front of the head panel, 10F speaker is mounted on the back, super tweeter too, providing a better time alignment.
The weird thing in front of the B102 is a 3D printed diffuser, which helps for directivity, and protect the speaker a bit. Measurements and listening proved it is a good thing in this setup.
About filtering, i use minisharc IIR and FIR, IIR is used to crossover & amplitude equalization, FIR to correct the phase.
I could go for FIR only but it is easier to tune like this for now. I'm using 48khz minisharc plugin to get more taps (and listening didn't show much difference with the 96khz version).
I'm using only 4 channels in this passive/active setup, because i found that 8 channels is theorically great (giving more control on filtering etc..), but requires 8 amplifiers, and 8 good amplifiers cost a lot, so i dropped average 8-channels class-D amplifiers for 2 very good stereo class AB SMPS-powered mechanically-silent amplifiers. And i don't regret it at all.
I tune bass channels and high channels (crossover slope/type/point, amplitude equalization, dipole compensation, etc...) then i measure the whole system for phase, and use Rephase to compensate, but i apply the same FIR on all channels. It is simple and works well for me. Amplitude and phase are quite flat at listening position, image has depth and width, sound is very impressive and transients very fast (a drum solo ... is a drum solo, a bass guitar or a upright bass sound big, voices are perfect to my taste). Frankly, not much to complain about, i just choose an album, press play and enjoy.
For measurements and tuning, i'm using Dayton Omnimic V2 with its mic, Holm impulse and REW with another mic, plus Rephase.
Room is around 6.5m x 4.5m x 2.3m, speakers are ~1m from back and side walls. Dipoles are great at preventing room vibrations, for me a main advantage in a flat.
The passive filter is very simple, one self in serie with B102, one capacitor in serie with 10F, one capacitor in serie with AMT tweeter, and few low value resistors to compensate sensitivity variations between those speakers.
The whole project was based on New Build: The Hestia V but i was already using 4xSDS 12 in my previous OB, with various 6 - 6 1/2 speakers (Visaton AL130, SB Acoustics Satori) + tweeter (ND25FA, Neo3PDR), all on the same panel, but it didn't work well, because the 6" speaker cannot go low enough, so i went for a 8", but 8" cannot go high enough, so i added a small speaker (10F). And it was a good idea, it works much better, especially with the 10F being about to reach very high frequencies. Adding a (super) tweeter is optional in this setup (it just adds a bit of "something", and makes things a bit more complicated).
I will rework the passive filter soon, there's room for improvement in this field.
Amplifiers are made of laser-cutted aluminium, using one FirstOne M + SMPS1200 + extra capacitors per channel, with very good heatsinks, they are linked, and controlled by arduino boards (so i can power on/off one and the other follows), but that's 2 stereo amps, totally satisfied with them, powerful and extremely neutral. I had like 30 different amplifiers, and those are definitively excellent. They just amplify.
The weird box with HDF front is my minisharc + DACs + their power supplies, with volume control (digital, with remoter). DACs are 2x Curryman DACs (sold by minidsp), but i discovered they need a very good power supply to work well, current one is good, but i'm working on improving it. Music flows through SPDIF from a computer-in-a-hifi-box music server running Kodi, and files are stored mostly in FLAC format (either my own ripped CDs, or legally downloaded, 1500+ releases up to 192khz/24 bits).
Voilà
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Zas,
Thank you for details. Very impressive. I'm sure it sounds glorious. You have pretty much put together a top-flight system using nice components known for great performance and value. Do you have any in room frequency response measurements with xo regions for each driver to share as well?
Great job!
Thank you for details. Very impressive. I'm sure it sounds glorious. You have pretty much put together a top-flight system using nice components known for great performance and value. Do you have any in room frequency response measurements with xo regions for each driver to share as well?
Great job!
Very nice speakers Zas!
In other news, holiday is over, so the construction is progressing again. I completed the 10F/8424 speakers late yesterday and got the first sounds out of them. Sounds very pure, bass is light due to no BSC and closed enclosure. The absence of baffle diffractions is pretty interesting. They do need some EQ, but nothing the MiniDSP wouldn't manage.
Pictures coming a bit later.
In other news, holiday is over, so the construction is progressing again. I completed the 10F/8424 speakers late yesterday and got the first sounds out of them. Sounds very pure, bass is light due to no BSC and closed enclosure. The absence of baffle diffractions is pretty interesting. They do need some EQ, but nothing the MiniDSP wouldn't manage.
Pictures coming a bit later.
No pictures of the FR yet since the listening room is a total mess with the woofers still under construction. However, here's some images of the upcoming 2x Ripole subwoofers. The last one is quite unrelated, my assistant is inspecting my previous built where I salvaged the 10F and second pair of SLS 12 from.
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My built is complete. Only thing left is to get some fabric for the acoustic panels. Overall satisfaction with this is completely over the top, everything turned out so nicely. The spherical bamboo cabinet is very solid, even with high volumes you barely feel any vibration. Woofers are even deader with the drivers facing eachother. The quality of bass is amazing with the Ripole after EQing it. Very fast and musical bass with quick attack and decay. My room curve is based on the -6dB 20Hz to 20kHz curve but with a bit more bass. The DDRC-24 is running EQ from 20Hz to 1,5kHz, after that it's just purely the 10F playing as it wants to.
Anyhow, here's some images of the setup and a measurement taken at the sweet spot on my seat
Measurement:
https://www.dropbox.com/s/b2e8hpmnl1scxbg/Sweet spot.mdat?dl=0
Anyhow, here's some images of the setup and a measurement taken at the sweet spot on my seat
Measurement:
https://www.dropbox.com/s/b2e8hpmnl1scxbg/Sweet spot.mdat?dl=0
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As you can see from the picture, the 10F starts dropping off in 15kHz. This wouldn't be a problem if I was 20 years older, but I still hear up to 19kHz and would like to hear the really high stuff as well.
As such, I think a super tweeter would be necessary for the built. I am thinking something quite simple and small, perhaps a B&W style drop shaped tweet mounted on top or under of the sphere. I will either 3d print or mould the enclosure myself. As such, the tweeter would have to be either press mount or otherwise without a flange. Does anyone have good suggestions for a candidate that would match the 10F well? I am currently thinking of Dayton Mini-8, as it has the same sensitivity and impedance
As such, I think a super tweeter would be necessary for the built. I am thinking something quite simple and small, perhaps a B&W style drop shaped tweet mounted on top or under of the sphere. I will either 3d print or mould the enclosure myself. As such, the tweeter would have to be either press mount or otherwise without a flange. Does anyone have good suggestions for a candidate that would match the 10F well? I am currently thinking of Dayton Mini-8, as it has the same sensitivity and impedance
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Got to disappoint you there, but it's symmetrical 4th order LR at 250Hz. The phase matching etc is done with the Dirac box (DDRC-24), which uses mixed FIR and IIR filtering to match the responses and reduce the room effects.
In other news, ordered a pair of the Dayton Mini 8s because they cost next to nothing compared to what I've already used on this. Eyeing Bessel filter slopes for those. I have a big ol' box of crossover components waiting for a lot of tests and measurements to push out that extra few percents of quality. They roll off early, but exhibit very good distortion graphs so filtering shouldn't be too hard.
Actually not at all. The TDA8932 amps have 36dB gain, the NAD only 23dB. I merely matched the levels by cutting the extra stuff off from other frequencies
13dB of boost and manipulation for 25Hz rolloff is not bad
Before you try the tweeter use REW EQ on your measurement and put in a high shelf around 12 to 15K and see how much you need to bring the very top end up.
Put that filter in your minidsp and as you've got dirac it should conform it to your target. Check distortion before and after to make sure you haven't overdone it.
Whilst you may be able to perceive a 19K tone there still isn't much musical information up there so you might not hear much difference between if the speaker doesn't reproduce it. Also remember that you could introduce more distortion or boost noise from your signal chain which might make it sound different too.
Worth a try before you start adding in a tweeter anyway
I'm actually only running the Dirac EQ at 20-1500Hz region. The 10F is quite pure after that, and Diracs (imo) quite aggressive approach on filter side doesn't do the HF response any good. So if I add a tweeter, it's going to be a passive XO.
Not a bad idea at all13dB of boost and manipulation for 25Hz rolloff is not bad
Before you try the tweeter use REW EQ on your measurement and put in a high shelf around 12 to 15K and see how much you need to bring the very top end up.
Put that filter in your minidsp and as you've got dirac it should conform it to your target. Check distortion before and after to make sure you haven't overdone it.
Whilst you may be able to perceive a 19K tone there still isn't much musical information up there so you might not hear much difference between if the speaker doesn't reproduce it. Also remember that you could introduce more distortion or boost noise from your signal chain which might make it sound different too.
Worth a try before you start adding in a tweeter anyway
I'll do some experiments when the tweeters arrive. I have some eBay cheapo tweeters which I briefly tried on with a simple 1uF cap and L-pad as crossover. Kinda liked the extra sparkle they added to the top after matching their levels.
A bit more tinkering with the EQ, response, etc. The high shelf on top end extended the response nicely. I doubt I need a tweeter anymore for this project. Here's dropbox file of the response measurement for anyone wanting to check it:
Dropbox - Sweet Spot3.mdat
Dropbox - Sweet Spot3.mdat
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