Paul Spencer Posted September 3, 2011 Author Share Posted September 3, 2011 Quite a bit done today. Mounting plate for the compression driver: All the bits cut: Including holes, which were quite awkward! Next up is making up a frame to help with assembling and a bit of a check to make sure everything is right. While I plan on getting the final thing done on CNC, physically building one from scratch is really good to get a feel for how it works and goes together. There are all kinds of details I didn't anticipate ahead of time. And of course, every dimension, every angle is different to what you might expect - all has to be worked out with trig. The side cuts aren't at 60 degrees, even though it's a 60 degree horn. Every edge has a specific angle, nothing is at right angles, except the ports and they had their issues as well. It all works out to be so much more complicated than expected, even though what you see is a dumbed down version! More on the blog: http://redspade-audio.blogspot.com/2011/09/synergy-horn-update.html Also managed to do a few things on the surround speakers. Link to comment Share on other sites More sharing options...
Guest Posted September 3, 2011 Share Posted September 3, 2011 Bloody work blocks your blog & pic's . Cheers Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 3, 2011 Author Share Posted September 3, 2011 Sorry Mal, I'll have to take down the topless pics so you can view! Link to comment Share on other sites More sharing options...
zog Posted September 4, 2011 Share Posted September 4, 2011 good to see the project is moving along, very impressive!! Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 4, 2011 Author Share Posted September 4, 2011 I just need one more full day to work on this and I should start making some noise! Didn't get to touch it today Link to comment Share on other sites More sharing options...
gainphile Posted September 4, 2011 Share Posted September 4, 2011 The buzzer like all power tools is a very dangerous piece of equipment. My poppa chopped off part of his index finger many years ago. When I heard about his accident as a little boy, it inspired caution with power tools. Believe it or not I was ready to make a DIY table saw !! Lucky a quick google/youtube put me to my senses. Apparently anything with high circular motion are VERY dangerous and kickback/binding are real problems. Some 60,000 injuries in USA/year, they even have lawyers specialising in table saw!! I'm now looking for a good quality jigsaw. Apparently they have good safety record (and hence why I still have all my fingers despite making speakers these few years) lol.. Link to comment Share on other sites More sharing options...
DQ828 Posted September 4, 2011 Share Posted September 4, 2011 (edited) Gainphile You need to buy yourself one of these , I would if I could afford it.Festool make the best jig saws I've ever used but once again you pay for it. Go the Bandsaw Paul Your a very adventurous man, I hope they sound good, bloody good. It's VERY handy having access to a CNC router. Looking forward to seeing the result. Edited September 4, 2011 by DQ828 Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 4, 2011 Author Share Posted September 4, 2011 CNC routers are all over the place now. I've usually done things the slow way in the past. Then one day Roger came over with CNC cut bits and it all came together so fast it was a bit of an eye opener. You can have a working speaker in a weekend! It doesn't cost much to buy a table saw, if I didn't have access to one I'd buy one. I make sure my hands never come anywhere near the saw. Only thing is if you buy large sheets then you need two people to cut them up. If you always work as a one man band then you can just get a portable circular saw. With a bit more time and effort one person can cut up a big sheet. Most of the cuts for the Synergy horn had to be done that way, except at weird angles. Your a very adventurous man I wanted a challenge! And I couldn't think of anything more difficult than this. The Synergy also has a few traits that suit me right now. Believe it or not I was ready to make a DIY table saw That's one thing I wouldn't DIY. It's a lot of work to make something decent, and you can buy them so cheap. You could spend two whole weeks on a project like that, or a whole lot of weekends! Most guys wouldn't find enough spare time in a year to do it. Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 Almost there ... shortly I'll be firing them up for the first time ... they are a bit bigger than expected! Link to comment Share on other sites More sharing options...
Drizt Posted September 11, 2011 Share Posted September 11, 2011 Almost there ... shortly I'll be firing them up for the first time ... they are a bit bigger than expected! lol, they were always going to be monsters :o Can't wait to see the pics. Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 almost there ....... Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 Everything takes ages when there are 8 midrange drivers! ... still hooking up cables Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 Now they are up and running. A few shots taken just before I set them up: Link to comment Share on other sites More sharing options...
Drizt Posted September 11, 2011 Share Posted September 11, 2011 How do they sound? Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 Without a proper crossover, ie just a guessed one ... LOUD! I'm working on a crossover now, the mids extend lower than expected, but only require just one broad notch filter to smooth things out. The compression driver is reasonably smooth in the horn. The black widows now have to come back in but they only have to get up to about 230 Hz, a good thing because they have early roll off and by 300 Hz lose their high efficiency. First impression, without doing it properly they don't sound as good as the surrounds, but that's no surprise. These are a lot more tricky. Link to comment Share on other sites More sharing options...
gainphile Posted September 11, 2011 Share Posted September 11, 2011 Very nice...! Is it the same size as Roger's Unities? Hard to tell without reference scale. Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 These are super sized. Roger's are 465mm external, mine are 540mm so they can run a little lower. There is some room for improvement but they are performing really well. They image differently to waveguide speakers and they are stupidly sensitive. When the mids see 0.01w they kick serious butt! The Black Widow woofers need some work now ... I'm waiting for some pro speaker stands to show, I'll build a really nice polar measurement rig. A bit like yours but mine won't double as an ironing board. I'm really curious to see how this thing measures off axis. Link to comment Share on other sites More sharing options...
gainphile Posted September 11, 2011 Share Posted September 11, 2011 It would be interesting how you'd rotate that thing at the mouth! Perhaps move the mic circularly instead? Link to comment Share on other sites More sharing options...
fury Posted September 11, 2011 Share Posted September 11, 2011 They look fantastic Paul! Can't wait to see measurements of these things! Link to comment Share on other sites More sharing options...
DQ828 Posted September 11, 2011 Share Posted September 11, 2011 How's the WAF? Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 11, 2011 Author Share Posted September 11, 2011 (edited) When these are integrated into bass traps in the corners, pretty good! You won't see them. They will be less obtrusive than a stand mount mini monitor placed into the room. I couldn't live with these placed into the room. When I was shifting them to the room, I was thinking that I really like the industrial military look! I took enough measurements to knock up a crossover. Just one notch filter and one shelving filter. Andi, I'd probably just do it the usual way and not worry about the axis being away from the mouth. The midrange is really well filtered, it drops off really quick so the top end is 30 db down. That means distortion is also 30 db down. The imaging has a certain directness that seems to be related to the narrow dispersion. There is no sense of room sound about it, it's as if the speakers create their own sound stage, kind of like they bring their own setup. Not easy to explain but I've noticed a similar thing with other horns. I've taken a lot of photos but haven't had time to upload them. Edited September 11, 2011 by Paul Spencer Link to comment Share on other sites More sharing options...
gainphile Posted September 11, 2011 Share Posted September 11, 2011 Wow that's ridiculously good!, ... like textbook filters! The problem with not rotating at the mouth as axis is by the time you'd go > 75deg, the mic is pointing to the side of the speakers/horns! edit: how come there's none of that characteristic dip due to the holes ? let's say between 1-3khz ? Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 12, 2011 Author Share Posted September 12, 2011 (edited) Good question Andi! The top end is smoother than my 6" oblate spheroid! I didn't even bother putting blue tak at the apex where the circle becomes a square. I also found out the other day in opening up the DE250 that the phase plug and exit tube is moulded plastic! It has concentric rings begging to be sanded smooth, and a gap at the end of the exit tube. Basically, it's not very well made and little details weren't done too well. I will address those later, not sure if it will make a real difference, but I'll feel better about it! Back to the question, I believe the key lies in making the holes small and putting them in the corners so that they have minimal effect. I should have measured without any holes at all, but I could go back and plug them. It has taken quite a bit of time to do all this, 3 weekends. I think the Pyramid shape helps with the smoothness where circular horns and waveguides have the diffraction dip. I used to think the ideal was an elliptical OS, but in this design the corners are needed, so I think the pyramid is the best. I had to bring back a hump at 320 Hz by 6 db, but once that was done, the midrange was flat. Even without filters, the top end drops right off. It happened just like in the sims. Sim vs measurements: raw, with EQ then also with xo filters ... easy peasy! Now what stands out is the Black Widow woofers. There is something going on at the top end of their response. The chipboard in front of the woofer in the front chamber vibrates like crazy and it sounds like there is some ringing/resonant behaviour in there. Edited September 12, 2011 by Paul Spencer Link to comment Share on other sites More sharing options...
Paul Spencer Posted September 12, 2011 Author Share Posted September 12, 2011 Two things really stand out about these. Firstly, they are very dynamic, they are just begging to be turned up. The sound does not change, even at very high levels. The sensitivity is about 102 db on the mids, 96 db for the bass and 109 db at the top end. The miniwaves had 89 db and going to the 8" B&C was quite a change with about 94 db, but this is on a whole new level. One track I played was from the Gladiator Sound track. It was spectacular, the ease with which the sound level jumps up is really needed to appreciate it fully. They are able to carry a certain level of raw emotion that in the past would have been tainted by strain and worrying about voice coils melting and drivers bottoming! Dynamics are there in spades. The other aspect that stands out is their connection to the room. It's as if they bring their own space. There is a certain clarity to the imaging, but I think I'd prefer it if the room could come back into the sound more. I think the dispersion is a bit narrow at 60 degrees. I chose 60 to make it work and extend down low, and that did happen. I think I prefer 90 degrees. So you might say there are two jumps. Firstly, you start with a normal box speaker with small drivers and wide dispersion. Say a 6" mid with 90 degree dispersion at 2k which transitions to a 1" dome tweeter at 2.4k which is very wide in dispersion. Maybe 120 degrees? The sound is spacious as the room comes into it. Now we go to a waveguide speaker and keep things to no wider than 90 degrees. We can still get some spaciousness, but the image is quite strong and stable. In my miniwaves I'd bring in the waveguide at 2k and get 90 degree dispersion above that. Similar thing with the 8" drivers, just better quality. Now this goes the next step, too far I think. I'll give it some time and I might try to do a 60 x 90 degree version with 6 mid drivers. Link to comment Share on other sites More sharing options...
gainphile Posted September 12, 2011 Share Posted September 12, 2011 Different room engagement/reverb is definitely something I experience with these types of speakers. I found out that with narrow dispersion the speakers really begs to be played loud. When I play my econowaves at "satisfactionary level" it would almost be VERY loud to other people ie. kids, wife. The non-compression really helps. I found these when listening to the unities too at Roger's. But with the dipoles, it does not need to be played very loud. So how these speakers engage the room perhaps influence the perceived loudness. Link to comment Share on other sites More sharing options...
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