EV DL 12W Horn Project Complete!
It's been several weeks now and my project has found completion. I always have loved a well made mid/ tweeter horn system- similar to Heresy's but much better. I liked the idea behind Heresy's- a compact system with a big sonic foot print, all be it bass shy and some what piercing to the ear. The Super 7 from Speakerlab was another favorite system but even it was a bit "shouty" at times and the bass could be boomy to me. The holy grail with my project was a smooth upper horn sound with solid tight bass extention. Worst of all I was budget restricted- but determined with time on my side.
Well the time thing has finally panned out. I first aquired the EV ST350B tweeters with a good BIN from an auction site, and they even worked! Upon investigation on an EV white paper it required some taming with their network compensation recommendations to kill some peakiness issues. About a month ago a friend made me some deals for a couple of fantastic EV DL 12W woofers- the foundation was al last laid. I solicited opinions from AKers for mid driver ideas and Paul C. convinced me into a pair of KSN/ CTS 1188A Piezo mid drivers. I was VERY hesitant to say the least but relied on his expertise. Piezos have ALWAYS defined shrill to me! I got them to really see if he was anyways near accurate in his decription of their inherant smoothness and power handling. I am glad to say PAUL C was dead on!! That particular mid driver, when I A'B'd them with several other really good horn drivers like the 1823M, K 55, etc. did a much better job of sounding smooth and non invasive. While not horribly efficient (about 94db) the smoothness was buttery soft. Combined with the 5" x 15" lens these were perfect for my sonic needs.
Next was a cabinet search, short of building my own which I was not beyond doing. Having done my Woofer Tester III/ "Q" home work on the EV woofers a cabinet volume of 2~3 cu ft was good for my needs of reaching the mid 30 hz bass area. My local good friend came through again with a couple of decent Infinity Studio Monitor 120 cabinets of 2.58 cu ft., again for trade out favors. I cut the front baffles out of them and did a fair amount of corrective internal bracing. The front baffles are now 1.5" thick, the rear venting set up for 35hz, etc. Believe me when you use the DL 12W woofer you will need a good thick front baffle and good internal btacing. Now was my next delima- what driver arrangement did I want. Something unconventional would be nice and I read about a couple designs that seemed well founded, the Mach 1 and an older Aztec 12" horn design. Those had the tweeter in an MTW arrangement, with the diffusion lens on those EV tweeters this could be a real plus as well.
Brining it all together with a well thought out crossover was next. The woofer was pretty good out to 1.2k, the tweeter did pretty good starting at 4.5k and the 1188A mid was pretty good in the 500~ 8khz range with a minmal slope at that! What I ended up with was an 800hz/ -6db oct for the mids and woofers and a 6khz/ -12db oct for the tweeter. This design fell in the sweet spots of the drivers ideal opperating freqency and ohm ranges. Air core inductors and Mylar caps used through out. Respective of the fact these drivers had good frequency ranges the "simple is better" approach was used when using the -6 db/ oct slope was chosen. Adding in the two 75 watt L-Pads for each set of horn drivers gave me fleaxability in placement and taming of the horns when needed. They also had a nice LED 100watt display should I want to monitor the power levels.
After much work fitting and refitting the plan came together. I set them up and started testing. First with a series of test tones the onto my favorite music selection. Everything was going superb. my L-Pads adjusted, placement set, etc. Then "wham" it happeded....when appling a fair amount of power ( I have a 500 watt Crown 1600!) part of the surround on one of the woofer came unglued! I pulled the woofer took it to the repair bench reglued it, and the rest of the surround and dust cap as well. Seems age has been taking it toll on that baby. I checked the other woofer as well but it did not seem to have any issues like the other one.
Next day everything was put back together and testing continued. This was by far the best speaker system with 12" woofers and horns I had ever built and even better than anything I have heard comercially built!! My neighbor brought over his 1978 Heresy's and completely agreed. The EV woofers were very comanding- very tight with great authority. The mids horns better than expected with very smooth redition and inteligble. The tweeters set it all off blending perfectly with the mid horns and adding the high end splash without beeming. You get the impression the tweeters frequency are coming straight from the mid horn throat. The L-Pads are set back about 20% for a pretty good blend of everthing. The overall sound is very exciting to me, even at volume these are not particularly invasive- truly a fun speaker system to sit around and listen to. That brings me to another point- I usually get fatiqued after listening to horns for more than an hour or so. These I did not!! I was well into hour 2 and still being very entertained by the sound. To be the rather small size they are (33x17x12) they pack one hell of a puch- very unassuming for sure.
While I have been very please with my Magnapan SMG's I am certainly going to have to move these into their place and do more intense "testing". My wife love the sound of the SMG's but not wild about the space taken from them. These may yet make her more happy on space retrieval! Oh ya- gotta make some grill covers too.
So what do I know now? I know a good quality horn system can be made to suit my personal taste with out being overtly large like a Klipsch LaScalla (my all time favorite home horn system). Horns can sound smooth, tamed and able to be listened to at length. Not all Piezos are all bad. Well back to listening- I am finally enjoying horns once again!
DC
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I bought this array kit from Selah Audio a while back, it has 32 - 3" drivers and 8 ribbon tweeters per box. The other one is better than 3/4 done but I still have to wire them up. I had so much fun building these that I decided to build a center, two surrounds, and 2 subs. The subs will each have 2 - 12", one on top of each other. The center is a design that Rick from Selah already had called the sardonyx, but the two surrounds are new. Each is an array 60" high, same height as fronts, a little narrower, with 12 - 4" drivers and 8 planers:yes: I think the rest of the summer will be spent cutting MDF!!