Another SEOS design. This one is very cheap.

Discussion in 'DIY Speakers and Subwoofers' started by tuxedocivic, Nov 9, 2012.

  1. Eminence Alpha8a with SEOS 12 and DNA150

    I think it looks pretty nice actually.

    Very simple cross over. Every effort was made to keep this as simple as possible. Budget was the name of the game. Having said that though, I can't live with anything that's not quality. So I didn't skimp on quality to save a $2 part. The final impedance is a very easy to drive load, except at very high frequencies. Above 20khz this approaches 2 or 3ohms. Even lower way way up.

    This is really as cheap of a SEOS build I think we'll see. You'll need this from PE.

    And from Erich, you'll need:
    And the optional flat pack enclosure:
    Or just the baffle:
    All said including the baffle - $130.15 per speaker. $25 more if you wanted the whole enclosure flat pack.

    Measurements are shown below.
    I've been playing with this speaker for about 3 months. I've been playing with the idea of this speaker even longer. It sounds very good for the money. I'm really happy with it. I may do a version with the DNA-205.

    A few things, power handling is about 100watts max. This is a little bit tweeter and woofer related. With a 80 or 90hz sub cross over, the woofer runs a tad past xmax at 100watts. The nice thing is, this alpha8a has a great bass response, on paper and audibly. So matching to subs is a piece of cake. Just keep the xo above 80hz. The little DNA-150 is also crossed over at 1700hz. It's a slow transfer function, so it should be ok. But 100watts would push this little guy. It's down 19db by 2khz, so it would take 64 watts just to get it to 1 watt levels. This is ok. Realistically, most receivers can't hurt this speaker, but it is not as bullet proof as these other SEOS designs. Keep that in mind.

    The other thing is the enclosure. I put ports in my flat pack enclosure, but I stuffed it very full. Even some stuffing in front of the vents. It's essentially sealed. Check out winisd for different alignments. But if someone doesn't know how to do this and wants direction... Build it 20L and seal it. It's the easiest way to go. If you really want bass extention, ported works well with this guy too.
  2. Forgot to add this to my photobucket. Here's a lazy way. PCD model. I'm pretty confident my measurements will match ;)

    Attached Files:

  3. Woot!

    Looks like a very nice surround speaker. I wish the NS6 budget had used this HF driver.

    You say excursion is a problem ported(what frequency tuning) @80Hz/100w. Wouldn't excursion be higher for the sealed, is that a problem? Sorry for simple questions can't model on this PC.
  4. No problem asking. Thanks for asking. Let me clarify a bit. The box I'm using is the 0.75cuft baffle, but I built my box about 30L (1cuft). I have ports installed for quite a low tune. Like 40hz. But it's so stuffed that it's basically a sealed box. (I should run a z sweep to see what this thing actually looks like). It sounds good like this. Even run full range the bass is ok. For crossing to a sub it's great.

    As for excursion, I'm basing this purely on winisd xmax plots. For 20L (0.75cuft) sealed, and an 80hz subwoofer cross over, it runs over xmax at about 100watts. If you were to port and tune it quite high, like 70 or 80hz, you're right, it could take more power. But I figure the power handling is somewhat fair because of the tweeter limits as well. The tweeter is rated for 30 watts. Because I've got such a slow falling transfer function, it can take much more than that without a thermal issue. And on the low end, it's down far enough that I think 100 watts is fair.

    Ya, I totally agree that this would be a good surround option. It's surprising small. I'll post some pictures with some sort of scale to show how it really is. No problem hanging this on the wall. The 8" woofer is light. Would also work in wall with some added thickness to the bottom end.

    Don't get me wrong though, it's not an overnight sensation. It's still got heft.
  5. Nice!

    There is not going to be shortage of design choices for any setup thats for sure.
  6. On axis


    I was in a rush, no verticals and only a few off axis horizontal. Roughly 10, 25 and 40 degrees. Bottom line, it works well despite the high xo because the 8" woofer is small.


    And the really cool part, here is the bass response. As mentioned above, this is like a 30L sealed. This was a semi near field measurement. Like 18" away. Not gating, just a touch of smoothing.


    In my opinion, this doesn't do much wrong other than possibly not quite make it to reference levels depending on your listening distance. I'll be personally using an in wall variation of it, since I'm not about SPL.
  7. very nice Tux. What changes did you make for the inwall variant?
  8. Simple, yet elegant. I'd expect no less from you TC.
    If I looked as good as this speaker, I'd admire myself in a mirror all day.
    I gotta try these when I get the chance. These and a few others. Great price, too.
  9. Thanks to you both.

    Craig, I haven't designed it yet. That's beginning soon. It may be as simple as tweeter padding or as complex as using Erich's new CD, the DE10 competitor. I really like that CD so I'll likely do that. You can expect some documentation on it though. I think SEOS is due for some in wall love ;)
  10. Sweet.I'll certainly be watching. I'll spend the next few months trying to convince the wifey that the jbl hti8's that are used as surrounds sound like an underwater tuba. Okay,there really not bad but they just can't keep up with the SEOS's.

  11. There was some talk about active in the "Hey guys" thread over on AVS, so I thought I'd start adding active settings to my builds again.

    Low Pass = Butterworth 5th (30db/oct) @ 1,200hz
    Level = 0db
    Delay = 0ms
    EQ = 600hz, -4db, 1.0

    High Pass = Butterworth 1st (6db/oct) @ 10,000hz
    Level = -3db
    Delay = 0ms
    6,250hz, -6db, 0.8
    2,500hz, -3db, 2.0
    5,000hz, -1db, 2.0
    15,000hz, +3db, 1.0

    Likely nobody except me will use them, but they're there.
  12. Arrgh, I have the 2-way GEQ plug-in. Are those settings for the 2-way advanced or 2-way + sub plug-in?
  13. Looks like the 2-way advanced is the proper one.
  14. It looks like minidsp has changed their plug ins. I can't remember if I have the advanced or GEQ, I must have the advanced. But I haven't done biquads with it.

    Anyways, it looks like the 2-way GEQ is capable enough it could do this particular cross over. I have active cross overs available for the Fusion Pure/Max and Wall as well, but I'd have to look at those to see if the 2-way GEQ could do it. If the eq is on the driver output near the cross over, I don't think it could. Even this one has a 2500hz eq that would be dicey.

    Let me know if I can offer any help.
  15. I did not see the higher slope butterworth in the GEQ plug-in. No worries, I went ahead and downloaded the advanced.

    Thanks, I will likely need some additional help when the drivers arrive.
  16. Ah shoot. You're right. MiniDSP must have changed their plug ins around. I'm pretty sure their basic plug in used to do it. Are plug ins still $10?
  17. Hey Tux,
    Was the high pass filter set to 1700 in the active? I think there is a typo in the original specs.
  18. Actually no. It does look like a typo but I used the very high 6db/oct as a shelving filter.

    Does it sound wrong? Or did it just make you wonder why it was so high? Let me know how it goes :)
  19. I'm awaiting the arrival of my Denovo and Seos, so I was just playing with the alpha and some tweeters I had on-hand. A fun way to experiment and learn a bit more about your design and the science/art that is a crossover.
  20. Yay! The waveguide, CD, and Baffles arrived today.

    Erich was kind enough to set me up with the slot ports, which makes for a nice look. The baffle is 14.5" wide X 18.5" tall and oozes quality, what a time saver.
  21. Cool. I'd like to see a picture of your baffle if you can. Slot ports would look pretty cool I think. What volume and tuning are you shooting for? Will you stuff it full like I did, or let the ports make bass?

    The baffle in my OP is from Erich, and like you said, it's cut very nicely. CNC is much better than my table saw :eek:
  22. Warning! Crappy cell phone pic attached.
    You need a real name for this design. Given, she has a short and stout baffle and the alpha 8 is fo shure a bit retro.
    I'm thinking "Roller Derby" --- Any other ideas out there?
    I'll be sticking with the 30L-36L box and shooting to retain the 40hz tuning from your design. I'll need to compute the box depth and port length to make this happen.

    Attached Files:

  23. Sure - Roller Derby sounds cool to me. It does look like an 80s DJ speaker. Big black boxes with an 8" woofer and big horn. They need a metal mess grill over them and they'd fit in for sure. The kind that hurt your ears as you skate by. Hopefully these don't do that to you :eek:

    They look great with the slot port. Can't wait to hear how the bass is for you with the ports open. No sub?
  24. Grills??? Strange that you mention that. I ordered these from PE to lend some visual balance.
    I had originally thought these would be my new L & R mains. They would have been used with my two Alpha 15" subs (Props to Martin King and Jim Griffin for their H frame design) for the TV room. Unfortunately, these babies are just a bit too wide for my cabinet, so they may become my new sub-free back yard/garage speakers. So the Jacks (but with the DW-6534S) wave guide may be promoted to the TV room.
    Noticed that the passive crossover between the two models is quite different, do you happen to have an active for Jack?
    Having lots of fun listening to the Alpha8/DNA-150 with SEOS12 and the DW-6534S in a test box. Mini-DSP's are a good thing!
  25. Ha! That grill is awesome. Definitely a roller derby style DJ speaker. That's exactly the kind of grill I was thinking of.

    To bad they're to big for your spot. I do have an active xo for Jack that I never bothered to post. But you're using the DW-654S so it wouldn't be quite the same. I could possibly come up with something for you, it just might need some basic adjustment on the fly. Like tweeter level. I'll pm you some settings tomorrow.

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