Legis,
Very nice! I love the sound clips. Having a synergy and tapped horn combo myself I can imagine what you are experiencing in real life. Fantastic work on getting a passive XO system. Congratulations!
What sound clip artists/song are those?
Regarding Deltalites modulating CD's: I heard Danley puts a shorting inductor across CD terminals to stiffen suspension for low frequencies that feed back into vertex.
Very nice! I love the sound clips. Having a synergy and tapped horn combo myself I can imagine what you are experiencing in real life. Fantastic work on getting a passive XO system. Congratulations!
What sound clip artists/song are those?
Regarding Deltalites modulating CD's: I heard Danley puts a shorting inductor across CD terminals to stiffen suspension for low frequencies that feed back into vertex.
Legis,
Very nice! I love the sound clips. Having a synergy and tapped horn combo myself I can imagine what you are experiencing in real life. Fantastic work on getting a passive XO system. Congratulations!
What sound clip artists/song are those?
Regarding Deltalites modulating CD's: I heard Danley puts a shorting inductor across CD terminals to stiffen suspension for low frequencies that feed back into vertex.
I also noted that slightly decreasing the parallel inductor value and it's DCR provided somewhat better electrical damping scheme for the driver. I hope I can pull it off without ~400hz notch filter across the driver or resorting to impedance smoothing with an L-pad. I ordered some high end Jantzen Cross Coil foil inductors with more optimized values for the crossovers.
An externally hosted image should be here but it was not working when we last tested it.
For caps I have Mundof Supreme and Jantzen Superior-Z for the 2446J and Audyn Reference and ClarityCap MR for the 2404H. I could squeeze in mainly what I owned already with just about right values, so I did not have to buy all of them, luckily.
I thought I could also try and put some flow resistance (some cloth propably) between the adaptor plates of the driver to dampen it's impedance and "separate" it acousically more from the mids (never resort to electrical domain if you can do it acoustically
?). I have not tested it yet though. Some front cover speaker cloth would be ideal (very little HF attenuation) but I'm afraid it's propably too little "flow resistant" to do the job...The songs were "Nacho Picasso & Blue Sky Black Death - I'm To Blame For The Rain" from their new album "Stoned & Dethroned": I'm To Blame For The Rain | Blue Sky Black Death) and "Rhye - Last Dance" from album named "Woman": https://www.youtube.com/watch?v=0R5hNmFvK1I
Be diaphragms, Jantzen cross coil inductors, Mundorf Supreme, Jantzen Superior Z. You get all the cool toys.
Me, I get stuck with foam core speakers and a miniDSP.
Cloth blocks HF, not bass - it will go right through cloth. That is why polyyfill damping works inside a speaker.
I don't think the stiffening coil on the CD is going to affect your sound as HF's don't go through it. It is simply used to divert and dump LF's. Should probably have a low R in series to burn off the frequencies that do go through it.
Me, I get stuck with foam core speakers and a miniDSP.
Cloth blocks HF, not bass - it will go right through cloth. That is why polyyfill damping works inside a speaker.
I don't think the stiffening coil on the CD is going to affect your sound as HF's don't go through it. It is simply used to divert and dump LF's. Should probably have a low R in series to burn off the frequencies that do go through it.
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My solution to unterminated horn mouth edge diffraction.
The effect is quite small, like I predicted, but audible. Big horn has already very good acoustical impedance at the mouth so the high freq soundwaves do not bend/diffract too much around the corners (but of course they bend some). With smaller horns the effect of mouth damping/termination is very, very big, with big horns such as these the effect is much smaller.
The damper are squeezed against the horn and they also act like a mass dampers and damp the horn mechanically, which is nice. The dampers also offer some room treatment (total area of the dampers around the mouths is ~1,9m2 = size of one person mattress) and also inhibit the "acoustical feedback" from different angles from radianting back to the horn to some extent.
I have not done any measurements yet.
An externally hosted image should be here but it was not working when we last tested it.
The effect is quite small, like I predicted, but audible. Big horn has already very good acoustical impedance at the mouth so the high freq soundwaves do not bend/diffract too much around the corners (but of course they bend some). With smaller horns the effect of mouth damping/termination is very, very big, with big horns such as these the effect is much smaller.
The damper are squeezed against the horn and they also act like a mass dampers and damp the horn mechanically, which is nice. The dampers also offer some room treatment (total area of the dampers around the mouths is ~1,9m2 = size of one person mattress
) and also inhibit the "acoustical feedback" from different angles from radianting back to the horn to some extent.I have not done any measurements yet.
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The mouth is 120x100cm with the foams.
By the way, I have had some ideas regarding fine tuning the injection port's diffraction profile. I though that maybe something like this could work as port's cover
.
Another option is regular perforated metal like this
An externally hosted image should be here but it was not working when we last tested it.
It could be tuned with differend kinds of perforations to give more optimal diffraction profile.
It would also be possible to cover the metal sheet with some non-flow-resistant cloth.
What do you guys think?
I got the idea from here: Unity horn with 2 x Eminence Alpha 6 drivers - Page 2 - AVS | Home Theater Discussions And Reviews
Only a test will tell. The goal is to get something working with the current nicely shallowed and rounded ports without any mods to the port size (which would consume time like h*ll and I would also have to buy the red paint more!).
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Hi X, I have not accomplished anything worth reporting yet. I have also tried taping the injection ports completely closed. It had remarkably small effect on the response+polars overall.
Thanks sladdbarn and Byrtt! Like Byrtt said, things continue now mainly in the Horny Tales.
Ron,
You could use the same dimensions (check that your 15" has the same cut out, all 15" are not the same), though it would be better to make the horn slightly longer to end at a 2" exit size, rather than do the parabolic throat filling Legis had to do when he decided to use the horn for a JBL 2" exit rather than the larger cone driver originally planned.
The 15" injection ports could then also be moved closer to the HF driver throat, also improving dispersion by reducing off axis azimuth error.
The DH1A also can have it's 1.4" to 2" adapter "snout" removed, and become a "pancake" style 1.4" exit driver, which will have better dispersion than that afforded with the 2" exit, and reduce HF to mid distance even more. This makes the driver functionally identical to the DH1AMT driver.
The stainless steel screws holding the DH1A's aluminum adapter in place use a very tough "LocTite" compound, heating them with a torch or heat gun will make the LocTite soften, if you don't, you may break the screws off trying to remove them.
Art
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Hi Art, thanks for the info. I am assuming you are saying that if I have a 2" exit... I should end the horn at a 2" gap vs a point correct? Then I would just cap off the end with a flat board, and cut a 2" hole for the driver, correct?
Sounds like a good plan
. Big conical horn or "waveguide" equals great sound. Conical/OS and the like are also the only horn/waveguide types that one cares to listen when operated wide bandwidth (like a Synergy), eg. more that 2-3 octaves. Tractrix sounded horrible as wide bandwidth horn (500Hz - 20khz ) with it's duct-throat, I happened to try it (Stereolab SL-190) one month ago. (The "WC-sinks" have now changed their home already, not my cup of tea and I don't want to pursuit a traditional multiple horn system instead of synergy horn system.)An externally hosted image should be here but it was not working when we last tested it.
As for the dimensions, there are handfull of important ones, and the rest you can make however you like. I have scattered my horn's dimensions along this thread pretty much, at least all measures one needs to be able to make "something like them".
You were after the sensitivity. I believe these are around 100-105dB/1w sensitive. Enough for my needs and for my 8w 300B SET amplifiers (ear blasting levels), but not too sensitive to become a problem with hum/hiss. Pure active xo and comp driver = no go. At least make the attenuation of the comp driver with passive setup (resistors) even if using active xo.
I use "only" 2x15" per side (not 4pcs), and have also connected them in series to make the load easier. By the way, series connection sounds much better than parallel connection in a resonant system like a horn - against the general opinion (which says that parallel connection is generally better). The difference is very big in favor of the series connection, in a horn. (I was using traditional transistor amps when I dicovered this.)
I have also thought what would I improve upon (for my own needs in mind) if I would make new ones. I would not move injection port closer to the apex - I don't need more bandwidth for the mids. It would only make matters worse for the compression driver by causing more diffraction (making the injection ports acoustically more visible to the comp driver). Also it would make the time aligment worse in my design, I would need the mids to be even more closer to the listener if only the time coherency is considered.
= I would place the injection ports like i have placed 1/4 wl of XO point (500Hz) from the apex, = 17,2cm +/- 10-20%.
I'm still debating whether the injection ports should be horizontal slots (see Danley), vertical slots like In Dynamikks, greatly rounded circular slots like I have or some malformed shape like "a flower" to distribute the edge diffraction (distribute the distance from comp driver to the edge of the injection ports). I found out that shaping the throat curvy was best in my circular ports configuration: http://www.diyaudio.com/forums/multi-way/277565-legis-horny-tales-10.html
Sound waves like to transition smoothly.
An externally hosted image should be here but it was not working when we last tested it.
I don't believe that pancake driver is the best choice in Synergy. Drivers with build-in horn beam the high frequencies in the center of the horn more than pancake drivers, which makes the injection ports more invisible for build-in horn drivers, at least I think so. I predict a similar pancake driver would have more ragged response in a synergy, but I could be wrong and there is no difference.
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What do you mean by "Pancake driver", and "Build-in horn driver"...is a Pancake driver a coaxial, and Build-in a compression driver?
Legis,
Your quality of work is always inspirational!
1) In my conic/exponential SynTripP design, the mid injection ports are as physically close to possible to the "pancake driver" (soon to be upgraded to B&C drivers, rather than the current drivers made by the company famous for the speakers used in Marshall stacks..) and the resultant combined response has near flat phase response through the pass band overlap. Moving the injection port closer to the apex does not appreciably change bandwidth, but pushes the upper peak/dip higher. Getting as near a complete "fill" of the VTC (volume of the throat chamber) is important to be able to cross the HF driver high enough for low distortion when used at high power/high SPL as I do.
For domestic use by non-deaf individuals, even a 3" diaphragm may be crossed as low as 500 Hz and sound "good enough" for most.
2) I measured the response of the SynTripP prior to drilling the mid injection ports, there was very little measured difference after, and no audible difference I could detect with my old and abused hearing.
As far as ellisr63 choice of the EV DH1A, with or without the "snout" adapter I found their sound to be far cleaner than the 4" diaphragm JBL 2445 and 1.75" (or is it 2"?) 2425 drivers which I had been using up until 1991. Having switched to the DH1 in 1991, I have still found them preferable to the more current JBL 4" exit drivers, and even preferable to JBL's 3" berillium drivers, though the preference in the latter may be due to the difference in throat designs between the line arrays compared, I have never heard them on a conventional horn.
Art
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