I think Wesayso is looking for a new project now that his towers have reached perfection. No more to fiddle with on those towers. 🙂
That MDF and expoxy underneath it are deep enough to support a routed ring to provide clearance for the surround. Although that may weaken it pierce the whole MDF sheet with a ring cut. Probably best to add rings standoff. Volume filler piece can always be added after the fact to reduce front chamber volume.
A pair of Maltese outdoors at two meters high, two meters distance, (basically free space) produces 94.3 dB at 250 Hz, 94.4 dB at 500 Hz with 2.83 volts (nominal 2 watts per driver).
That is equivalent to 97.3 dB one watt one meter, distortion is -34.9 at 250 Hz, about 1.78%, and -48.5 at 500 Hz, less than .5%.
Raising input by 10 dB (20 watts per driver) raises distortion to around 3.16% at 250 Hz and a bit less than 1% at 500 Hz at the equivalent of 108 dB at one meter.
Extrapolating, at 160 watts driving four units (40 watts per driver), the peak output should be around 117 dB at 250Hz with about 6.5% distortion. Distortion at 117dB should be only about 2% at 500 Hz.
The TC9/Maltese horn ability to cross over at 250 Hz with high SPL makes it possible for an inexpensive 2-way covering 10 decades (20-20kHz) capable of producing the dynamics of the most demanding live music.
But it would require a deep bookshelf 😉.
Art
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That's what I figured too. It (the groove) would weaken the mounting area. Better to fill under the cone if needed. Just spilling my thoughts.
So far this is moving along very well! Always good to have alternatives 😀.
I'd suggest allowing for Xlim, rather than just Xmax. Hearing the surround hitting the baffle sucks.
Routing the ring around the surround rather than using a standoff ring will reduce the enclosed volume comparatively, which raises the upper peak frequency before the BP dip.
Good points chaps - particularly the xlim rather than xmax - cheers Art.
I thought a lot about the thickness of the MDF mounting plate, but I decided I wanted to keep it as thin as possible to minimize the length of the taps.
I have rings, because routing a ring would have required a mounting piece at least 2-3 times as thick, and I figured a filler piece would be better. Also I can simply add another disk of MDF with a ring routed if need be, but harder to make the mounting piece thinner once it is glued on!
This was my thought process anyway.
I thought a lot about the thickness of the MDF mounting plate, but I decided I wanted to keep it as thin as possible to minimize the length of the taps.
I have rings, because routing a ring would have required a mounting piece at least 2-3 times as thick, and I figured a filler piece would be better. Also I can simply add another disk of MDF with a ring routed if need be, but harder to make the mounting piece thinner once it is glued on!
This was my thought process anyway.
Better we cover this kind of topics now right? No harm done yet 😉.
What are you going to do for mounting points for the driver? Is there space for trough holes?
What are you going to do for mounting points for the driver? Is there space for trough holes?
Nice progress and ideas this thread : )
Got the bug too here, just ordered two different horns with 2" entrance that are low cost available in EU area at GB £32 and £25. Idea is first to measure and listen with a 10F and TC9 and after that see if they can be improved with bored up entrance or modified in some way as weltersys did. If it works fair will then order one more horn of the best performer of the two.
If it will improve diffraction with big round over exit think of after mounted on a flat baffle one can on front add a around 4" deep rectangular frame with inner dimensions same as mouth exit dimensions and sand that frame round to have round over exit as the bigger JMLC horns.
As this thread evolve can really see possibilities for great bigger home stereo system as wesayso suggested use one of the bigger JMLC horns so as to get constant diretivity down below 500Hz as also weltersys recommend and then add B&O 90 tech to control lows. They big horns seems available at - Horns by Auto-Tech but they costly.
Got the bug too here, just ordered two different horns with 2" entrance that are low cost available in EU area at GB £32 and £25. Idea is first to measure and listen with a 10F and TC9 and after that see if they can be improved with bored up entrance or modified in some way as weltersys did. If it works fair will then order one more horn of the best performer of the two.
If it will improve diffraction with big round over exit think of after mounted on a flat baffle one can on front add a around 4" deep rectangular frame with inner dimensions same as mouth exit dimensions and sand that frame round to have round over exit as the bigger JMLC horns.
As this thread evolve can really see possibilities for great bigger home stereo system as wesayso suggested use one of the bigger JMLC horns so as to get constant diretivity down below 500Hz as also weltersys recommend and then add B&O 90 tech to control lows. They big horns seems available at - Horns by Auto-Tech but they costly.
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Nice Byrtt! So we will have 18Sound XT1464, Faital Pro LTH142, and now P Audio PH-27233 PH-4528 and builds going on in this thread! Great to have multiple options to see what works. Art is doing the Maltese but I don't think his will have bass injection - and its not exactly bookshelf anymore 🙂
Wesayso, you are next! Since you are the one who brought up JMLC, you need to do the JMLC-400:
JMLC-400 - Horns by Auto-Tech
Or the wild looking E-JMLC-600:
Another option is the JBL 2386, which can be had for dirt cheap used ($35 in US). Martinsson has shown that this horn works well with a 2in Tang Band in this thread: http://www.diyaudio.com/forums/full-range/205146-2-madness-hornloading-tb-w2-803sm.html
JBL 2386 Horn, $34.99 – CLAIR Used Gear
Specs in JBL 2386: http://www.sound-image.com/wp-content/uploads/JBL_2386.pdf
Wesayso, you are next! Since you are the one who brought up JMLC, you need to do the JMLC-400:
JMLC-400 - Horns by Auto-Tech
An externally hosted image should be here but it was not working when we last tested it.
Or the wild looking E-JMLC-600:
An externally hosted image should be here but it was not working when we last tested it.
Another option is the JBL 2386, which can be had for dirt cheap used ($35 in US). Martinsson has shown that this horn works well with a 2in Tang Band in this thread: http://www.diyaudio.com/forums/full-range/205146-2-madness-hornloading-tb-w2-803sm.html
An externally hosted image should be here but it was not working when we last tested it.
JBL 2386 Horn, $34.99 – CLAIR Used Gear
Specs in JBL 2386: http://www.sound-image.com/wp-content/uploads/JBL_2386.pdf
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If I find a sponsor I will! 😀 I always kind of liked that last one:
Always reminds me of this:
Side view:
Am I still on topic? 😱
Always reminds me of this:
Side view:
Am I still on topic? 😱
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Yes, you are still on topic, perhaps it should be called the MJLC horn: Mick Jagger Le'Cleach horn 🙂
At least we would have a pretty good idea how to shape the enclosure!
Probably costs some extra though, portrait rights and all...
Probably costs some extra though, portrait rights and all...
And they both sing pretty well too. As a public figure, I don't think any portrait rights needed - you just can't call it a MJLC horn 🙂
Been asleep for about 30 posts, boy do you guys work quick! As far as the JMLC horns go, why not try using the facets worksheet from JMLC himself to design your own out of foam core? I've made a few out of thin MDF, and they work great - but you have to decide on throat, freq, expansion and no of faces. Bit of work but way cheaper than $400. Especially for experimenting. Take note that lower freq horns tend to get BIG quickly... I've got a 280hz 92mm throat that is 500mm deep and about 900 wide. That's approx 20" by 3ft.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Jurjenh,
Thanks for the tip on JMLC profile calculator spreadsheet. This looks to be te perfext foam core project! Although at this point I am more or less going with the general route of using a well developed and proven commercial horn and modifying it to use with a full range cone driver and then adding bass injection ports. Nonetheless, a foam core JMLC petal horn is definitely on my to do list.
Thanks for the tip on JMLC profile calculator spreadsheet. This looks to be te perfext foam core project! Although at this point I am more or less going with the general route of using a well developed and proven commercial horn and modifying it to use with a full range cone driver and then adding bass injection ports. Nonetheless, a foam core JMLC petal horn is definitely on my to do list.
Can't help but notice not much is being said about HOM's in this thread. There's no point in letting something that can be addressed not be, yes? Some of the horns I'm seeing are just that, classic horns. Lets let those things stay in the past and stick to low HOM waveguides. Am I alone in thinking this?
Everything is a tradeoff. The Synergy-derived horns trade the possibility of audible HOM's against point-source behavior to a much lower frequency than a Geddes-style OS waveguide + large direct radiating woofer can provide. Or, with xrk's priorities, trading off compression driver efficiency for lower distortion (and cost) from a horn-loaded cone driver.
Which would prove preferable? Hard to say without trying it.
Bill
Bill,
I see. Maybe in the future I can try doing a synergy with something like a SEOS24. (still bookshelf...right?) For now I'm working on a somewhat 'last generation' waveguide + large direct radiating woofer. Figure I would cut my teeth on something that is tried and true. And leave all the experimenting to the veterans. 😀
I see. Maybe in the future I can try doing a synergy with something like a SEOS24. (still bookshelf...right?) For now I'm working on a somewhat 'last generation' waveguide + large direct radiating woofer. Figure I would cut my teeth on something that is tried and true. And leave all the experimenting to the veterans. 😀