Fantastic work - I bet you wish you had 2...
From: https://en.wikipedia.org/wiki/Bristol_Mercury#/media/File:Bristol_Mercury_RAFM_Hendon.jpg
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From: https://en.wikipedia.org/wiki/Bristol_Mercury#/media/File:Bristol_Mercury_RAFM_Hendon.jpg
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I prefere that immensely compared to the square MEH. I even think they got charm. Grey suits it.
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The color is called "pigeon blue" and is a very light blue, in reality it is nicer than plain gray. It looks like grey in the picture though. The reason to go with 9 sided horn was that it allowed me to fit a lager horn on my CNC than if being square. For the yellow horn I had to make the top and bottom panels in two operations shifting the board between them. This is even larger diameter and the petals fit the bed easily - actually, an even larger horn could be made this way, but it would not fit the room anymore🙂
But I must say I like the looks, too🙂
But I must say I like the looks, too🙂
When looking at the picture in post #68, it should be possible to make that slight round-over on the petals at the horn-mouth on your CNC!?
You probably need a longer and stable router-bit to make the edges on the petals, when the material-thickness grows. Hmm. CNC rocks! 😀
You probably need a longer and stable router-bit to make the edges on the petals, when the material-thickness grows. Hmm. CNC rocks! 😀
For home audio use, you don’t need such high SPLs so no point in pursuing a CD for the throat driver. What about a small full range and a larger throat? A 2in 86dB full range can go low and with horn gain be about up to 10dB more sensitive. Lots of good quality 2in full range available. Trick is to make the adapter so you don’t have a cancellation at the throat transition.
A bit of info on this adapter is on the Bookshelf Point Source horn thread.
Nice project btw!
@hornsteff The CNC could definitely do that, the challenge is to create the model of the petal in OpenSCAD. The same issue is valid for curved petals, I can do roughly up to 50 mm thick petals in one layer and multilayer is practically unlimited.
@xrk971 Thanks! I was not very happy with full range drivers I tested on horns, but may give them a try again - the green horn would just need a different adapter, since there is GRS PT2522 at the moment. I am putting this on my list, a good point. I actually tried a Scan Speak R2604/833000 in the yellow horn - it needed lots of boost in the high end, but it was really nice, maybe a bit more natural than the compression driver.
@xrk971 Thanks! I was not very happy with full range drivers I tested on horns, but may give them a try again - the green horn would just need a different adapter, since there is GRS PT2522 at the moment. I am putting this on my list, a good point. I actually tried a Scan Speak R2604/833000 in the yellow horn - it needed lots of boost in the high end, but it was really nice, maybe a bit more natural than the compression driver.
The problem with AMTs, ribbons, and planars for horn loading is that they don’t achieve the 10dB gain that traditional dynamic drivers get. Something about their lack of ability to drive an air column down the throat. There is no “piston” power to speak of. Bit the horn directionally works great.
Amazing work in 9’sided horn! Crazy good looking.
Amazing work in 9’sided horn! Crazy good looking.
Hi xrk, can you give an example where you achieved that? A link to the bookself thread mentioned , or a direct build? Thx.
I tried several 2.5in drivers but the SB65WB25AC-4 had the smoothest response but lowest sensitivity. But with 10dB boost it was not too bad. The FR58EX has higher sensitivity but not as smooth.
Specifically, tractrix horns have nice gain. I consistently see 10dB in the middle part. It falls off at the very high frequency a bit.
https://www.diyaudio.com/community/threads/a-bookshelf-multi-way-point-source-horn.285030/
In the Trynergy thread I got +10dB with TC9FD and 10F/8424.
https://www.diyaudio.com/community/...rynergy-a-full-range-tractrix-synergy.261427/
In the PRV 5MR450NDY thread I got 10dB boost on 95dB midrange. It was very loud but so clear you didn’t know it was loud. I rang my ears a few times when doing sweeps because I forgot to wear earplugs.
https://www.diyaudio.com/community/threads/prv-5mr450-ndy-for-fast-waw-applications.259293/page-10
5MR450NDY in foam core tractrix:
Specifically, tractrix horns have nice gain. I consistently see 10dB in the middle part. It falls off at the very high frequency a bit.
https://www.diyaudio.com/community/threads/a-bookshelf-multi-way-point-source-horn.285030/
In the Trynergy thread I got +10dB with TC9FD and 10F/8424.
https://www.diyaudio.com/community/...rynergy-a-full-range-tractrix-synergy.261427/
In the PRV 5MR450NDY thread I got 10dB boost on 95dB midrange. It was very loud but so clear you didn’t know it was loud. I rang my ears a few times when doing sweeps because I forgot to wear earplugs.
https://www.diyaudio.com/community/threads/prv-5mr450-ndy-for-fast-waw-applications.259293/page-10
5MR450NDY in foam core tractrix:
but tractrix isn't constant directivity and the small full range drivers don't have the sensitivity to support equalizing for the treble roll off in the constant directivity horns some?most? of us prefer
The BMS 4550 is rated down to 800 Hz, where it has a steep roll off. I think its usable that low with a steep high pass.
I've used it in a synergy with XO at 1050. I could have gone lower but didn't need to...
The BMS 4550 is rated down to 800 Hz, where it has a steep roll off. I think its usable that low with a steep high pass.
I've used it in a synergy with XO at 1050. I could have gone lower but didn't need to...
Thanks for taking the time to give those examples, generous 🙂
How much or the gain do you attribute top reduced radiation angle vs true horn loading (efficiency increase)
+10 dB total is a lot and impressive imo.
I guess if a small mid is to be used in place of a CD, it comes down to how high can it reach, and maintain the gain
Hi Jaroslav
If only I had your talents with 3D-CAD, 3D-printing and CNC...... But I have many ideas!
DiyAudio member oohms from Australia has shared his "K402-replica-build", version 2 in wood, in the following link. He made a tractrix-like extension for the primary/initial flat horn flare. His extensions/secondary flares are also 50 mm thick! Here is the link:
https://www.stereonet.com/forums/topic/232459-klipsch-k402-replica-build/page/2/
Here comes my Idea. You could CNC nine curved extensions a bit like oohms did and glue/screw them to the existing flat petals. Maybe you have to shorten your existing petals? I think that could become almost A for Ara-like!
I hope that the idea is expressed clear enough.
Steffen
PS: You can only look at stereonet a few pages for "free", than you have to create an account. It does not cost anything but is a bit of trouble.
If only I had your talents with 3D-CAD, 3D-printing and CNC...... But I have many ideas!
DiyAudio member oohms from Australia has shared his "K402-replica-build", version 2 in wood, in the following link. He made a tractrix-like extension for the primary/initial flat horn flare. His extensions/secondary flares are also 50 mm thick! Here is the link:
https://www.stereonet.com/forums/topic/232459-klipsch-k402-replica-build/page/2/
Here comes my Idea. You could CNC nine curved extensions a bit like oohms did and glue/screw them to the existing flat petals. Maybe you have to shorten your existing petals? I think that could become almost A for Ara-like!
I hope that the idea is expressed clear enough.
Steffen
PS: You can only look at stereonet a few pages for "free", than you have to create an account. It does not cost anything but is a bit of trouble.
Reduced radiation angle would have worked for AMT and ribbons then if that were the case. Also, not sure if you can get 10dB from radiation angle.