Son of HF - Big Flower

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#21
Received the stands. Not completely acc to supplied drawings byt it will be OK once I add the concrete to the foot. Its actually quite stable as mounted on the picture but there are big pieces missing of course... 😉

S1.jpg
S2.jpg


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#22
And while waiting to assemble the second bass basket I play them sitting on the floor with one of the old bass boxes. Sounds really nice and interesting - it's a thrill to hear old and new records. This is how it measures in the listening position. It was a much easier EQ than the old ones - promising.

BFsweepedEQsoffa.jpg


Un-EQ'd. L complete, R with old bass. Surprisingly similar still... I think XO was set to 1400 + old system gain settings... well... 🙂

no_eq_LR.jpg


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#24
Looks amazing. Gorgeous design. But those 4 bolts holding the heavy concrete flower on the stand... I think that might be a failure point in the future. Any way to affix a metal plate across those 4 bolts to distribute the stress?

Edit - ahh, never mind. Now I see from previous pics that you embedded plates in the concrete.
 
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#28
In one of his recent videos DIYPerks made some speakers that had 3D printed twin walls with a void between the twin walls. He filled the void with a mixture of plaster of Paris and PVA. He reported that the walls of the cabinet were then completely dead / non-resonant. I’m thinking a similar technique could be used to make your rear basket as it would be easier than casting concrete.
 
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#30
@TNT: I think I’m right in saying that your aim is to create a virtual point source by using DSP to delay the horn output. A listener who is on-axis with the horn will not get any on-axis radiation from the woofers - it will all be reflected radiation, albeit time corrected. I’m guessing you have already thought about this and I’m interested to know if you think this will have an impact on your point source objective? ( This is not a snide comment - I think this is a very cool project ! )
 
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#31
@Studley What you say above about "on axis radiation" of the woofers is not correct. Yes, they are not pointing at the listener, but any driver radiates sound like a monopole (e.g. outwards in all directions) at a low enough frequency and only transitions to directional behavior above some frequency related to the cone diameter. These relatively small drivers (6" I think) are not directive until around 1kHz (see https://www.audiosciencereview.com/...r-beaming-frequency-formula.23816/post-804690) and produce a direct, on-axis sound pressure that will not really be much different than at 45 or 90 degrees off axis. Also, the design of the woofer section is sort of horn like when the speaker is backed against the wall, so I would expect that even up to almost 1kHz the sound pressure directly in front of the speaker will be very usable. The question is really at what frequency does this behavior start to break down and can the horn+driver be crossed over that low.
 
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#32
Thanks for your interesting comments and questions - these are also on my mind. I will measure the individual sections by themselfs - EQ and unEQd - and at least one octave beyond its intended pass band. And of course also directivity for the mentions cases. It will be interesting.

I'm hoping for a point source behaviour which I think will need a delay of the horn/HF section to meet the LF. What I heard form the SOundflowers, it seem to integrate fairly well but I hope for an even better one as I can push the XO down here. 1K seems absolutely feasible from what I hear now albeit a bit experimental setup 🙂

The sad thing is that I dont have a full wall to play on but it is a chimney coming up through the room so parts of the back of both speakers will fire into thin air.. maybe I can arrange for a temporary move o accommodate a more full "baffle"...

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#34
The axisymmetric nature of these ensures one plane of polar measurements of each range should tell much of the story.

Studley said:
to create a virtual point source
Click to expand...
A term I like to ignore since it's been overly misused and it's meaning broken, so I don't know your intent here.

I would see it from the point of view of directivity index (DI). The potential coaxial nature creating wavefront coincidence for power consistency.
 
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#37
this project is really impressive and it makes me envious but also really happy to see somebody bringing their ideas to life . I wanted to ask could the bass drivers be mounted to the back side of the horn facing forward and some small holes drilled near the center of the horn in the same way as a meh ? I know your design is almost complete as is but I just meant do you think my idea would work in theory ?
kind regards James
 
#38
In these individuals, no. But a MEH is always possible - and I think it is being made in the ATH thread. I'm not so keen on pressing all SD via a small hole when the drivers can breathe freely instead. I'm not so sure running them like I do would mean a big difference compared to a MEH speaker when both placed close to a wall. So why MEH... well, there isn't always a wall available ;-) + directivity.

I actually seek the properties of a point source and that means a fully spherical omni-directional small source - like a pulsating ping-pong ball that plays 20-20k, 120 dB, 0,01% THD in every single direction ;-D As I use a wall, I only have to accomplish that in 180 deg as the reflections from the wall makes up for the rest of the 180 deg - to a degree 😉

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#39
TNT said:
I actually seek the properties of a point source and that means a fully spherical omni-directional small source - like a pulsating ping-pong ball that plays 20-20k, 120 dB, 0,01% THD in every single direction ;-D As I use a wall, I only have to accomplish that in 180 deg as the reflections from the wall makes up for the rest of the 180 deg - to a degree 😉
Click to expand...
What I seek too: half-space hemispherically omni-directional coherent point-source -- by reflecting tweeters instead. (I had appended a tail comment to your older thread.)
W

Post in thread 'Hornflower 2-way point source'

Sorry I missed this great thread! Perhaps a ring of tweeters firing toward a convex reflector in lieu of horn throat and DSP delay?

 
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