Help me with Synergy

Discussion in 'Waveguides and Horns' started by johnnyrocket, Aug 25, 2016.

  1. I didn't want to hijack the spreadsheet synergy thread.

    So, I'm new to speaker building. If your like me, then sometimes noobs get on your nerves too. I'll try not to annoy you guys too much.

    Why am I here? Cuz Danley speakers sound amazing. First time I heard them was outdoors. It was an SM96 over a pair JTR Growlers. I was floored by the clear sound. The bass was awesome too. It so happens that I can't afford a pair of Danley's right now. And since I like DIY, I would rather build. Although these are tough to figure out.

    I'm looking to do all eminence drivers:
    Highs x1: NSD 2005 (1-inch compression driver)
    Mids x4: Alpha 3-8 (3-inch driver)
    Lows x2: Alpha-10A (10-inch midbass driver)

    FaitalPro also has some interesting drivers I like.

    I downloaded Synergy Calc V5. I need to become familiar with all the terms. But I couldn't find any fields to input the size of the drivers. Driver size will affect the final size of the horn panels.

    Am I missing this somewhere?
  2. Hi JohnnyRocket,

    You have to design the horn, then find drivers that can fit (and that can work in other ways.... not just any driver will work for a horn midrange, for example! - though, the one you picked looks like a likely choice assuming it has proper sealed volume behind it). If the drivers don't fit, lower the horn's pattern control frequency and/or its angles till your chosen drivers do fit. But that's kind of a backwards way of designing.

    With that spreadsheet, the horn is specified based on pattern control performance, not on what drivers could fit on its surfaces.

    BTW, you are going to have a BIG horn if you make a SynergyCalc-based design and want to put 10" drivers onto it! For example, a 90x40 design that just barely has room for 4x 6" woofers and 4x 2" midranges is already 24" wide. There are other more complicated constructions possible, though (but you'd probably have to work those out yourself). One thing to keep in mind is that the horn doesn't actually do anything for the woofers acoustically unless the horn is huge -- feeding the woofers through ports in the horn is just a way to keep their output positions centered physically close to the midranges for point-source behavior.
  3. Thanks Bill. I've been working on a small horn idea for PA/DJ use. The horn will be coupled with 10-inch front-firing woofers. Something similar to you SmallSyns design. I'll post my drawing when its done. Still have a few more days worth of work.
  4. Hi Johnny,

    Sounds like a plan.

    BTW, I'd recommend doing a Horn Response model of the midranges on a horn before you go too far. A problem with using some midranges is that the sealed area behind them needs to be so small to get them to work well as horn drivers that there's no good way to seal it. Best is if you can get away with putting a cup or mailing tube or cap or something over the back, but that's too much volume for many drivers. Some drivers need to basically have all the openings in the back of the driver covered right at the back (as if the openings in the basket had never been made), which is very difficult when they have the flexible wires from the voice coil needing to go through there!

    (Actually, best is if you can find a midrange that has its back already sealed).

    The sealed volume affects the lower end of the midrange's response. Too much volume and you might not get enough output down there -- opposite of what you'd probably expect. Though too little volume can hurt the low end of the midrange, too..... There's a sweet region where the mass of the air in the horn nulls the stiffness behind the cone and kicks up efficiency and smooths the output.
  5. Yeah. I decided to switch to the Celestion TF0410MR (sealed-back 4-inch driver). I can't find a smaller or more convenient closed back driver. Since these have been used on numerous builds I thought its the way to go. So in designing a somewhat compact cab, I'm finding the horn isn't going to be very big. Still learning Hornresponse software (haven't quite got it). I know I'm going about this backwards, but size and weight are somewhat important. Will probably have to come to a comprise somewhere. I still want very good clear loud sound. What do you think?
  6. Looks reasonable. I'm not sure how well the woofers will work aiming out like that, but I can't really think of a good reason why it wouldn't, assuming that it isn't playing up too high in frequency.

    If this is for home use and you aren't needing to play to auditoriums or stadiums, you really don't need three or four midranges in a horn. Even using only one of them would likely keep up easily with the tweeter. And the response would be smoother, too (the midrange ports are tolerable in a Synergy horn, but they still do degrade the tweeter response some -- if there's no need for them, I think it would be better to keep the tweeter range happier).
  7. This would be for PA use.
    I've been debating on only using 2 midrange drivers. That BMS driver is a 1.5-inch. There is a 1-inch neo compression driver available as well that would save me some weight. The 10-inch woofers are for mid-bass. This cab will be used with a subwoofer. Your suggestions are helpful.
  8. Something to consider.
    I haven't found anyone who has used a larger midrange driver in their design. The largest I've seen used is a 5-inch. Suitable closed-back drivers are hard to find. What's interesting to me is that Eminence makes a 6-inch closed back midrange that I think might work nicely. I like Eminence. Maybe thats the reason. Without measurements I don't really know. The driver is also larger which makes it harder to get close to the HF area. I like the idea of dropping the Celestion's and using two (2) of the Eminence LA6-CBMR mids. But I'm sure there's a reason to stay with small midrange drivers. Any thoughts?
  9. I've read an exhausting amount of information today on port locations for the midrange drivers. I don't think there's an exact way of figuring this out. Can someone comment on my drawing showing where I plan to place the midrange ports?
  10. You really have to simulate it in Horn Response to know (you'll have to, anyway, to find how big to make the ports). In all my Synergy designs so far, I had to go for getting the midrange ports in as close to the throat as I could get them, it keeps from having to make the tweeter run too low. I use 1" tweeters, too, a bigger tweeter will allow you to get lower.

    If for home use, there is no way you need two 6" drivers for midrange! Two 4 inchers will do. One 4 incher would probably do.

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