SEOS12/2512 Build - Page 3

Sorry, no build thread. I did snap a few photos before I stuck in the crossovers/drivers/wall lining. I ended up with 3 dowel braces, xyz planes....the third added after the photos. I built mine for portability, "PA" style....top carrying strap, rubber feet, pole mounts, 1/4" jacks. To each their own. Used HD's 3/4" "birch" ply, with Bombay Mahogany Polyshades. I botched the finish but I don't care right now, they sound awesome, and after a few Coronas they look fine.

Unfortunately (for my ears) most of my listening is near field. These took over my B2030P's territory, but they will get out on the lanai for a good workout beginning Tuesday night through the 4th.

I will say these are hands down the best speakers I have ever owned, not that I've had many. Had some McIntosh back in the day. These are just in a different class altogether, apples and oranges.






Edited by zhillsguy - 7/2/12 at 6:34pm

Dang.  Those are pretty.  At first when I saw the bars across the woofers I didn't think so, but scrolling down and seeing the whole baffle with SEOS and all...nice.

Everyone has different needs, "black holes" are cool, it's all good. I got in a hurry doing the finish and laid it on too thick in some spots.....but I'm listening to them now. I settled with about 1.7 cu. ft sealed.....16x22x12. I was going ported, but decided that for the extra couple of db it wasn't worth it. I cross them pretty high anyway (100 Hz +/-). These things are so efficient it's unreal. In my small "listening area" I run enough subs to complement....two Anarchys', one TC Sounds 12" 2000 sealed and a DIYMA reference 12" sealed. For outside, right now just one Dayton pro 15" in a 3 cu. ft. ported, but have a new 15" Peavey Low Rider coming this way for support.

Thanks bw.....couldn't have done it without you! The bars offer protection from bumps during the occasional "transport".
Edited by zhillsguy - 7/2/12 at 8:23pm

zhillsguy, those do look nice.

So did you use one of the current crossover plans? Or did you alter any of it besides the enclosure size? More info please! Drivers, etc. It's hard to remember screen names, real names, and what each person ordered, but I think you went with the DNA-350's didn't you?

I want to hurry up and get some kits out there for all these things, just not sure which to do first. Alos going to look into some completed crossover networks.


Any extra things we should know about mounting the waveguides or anything else?
Edited by Erich H - 7/3/12 at 4:08pm

Sorry Erich....had a busy day. I learned late this evening that my neighbor across the street had passed.....he was like our neighborhood rock, always there when you needed something....very sad.

I used the standard Eminence crossover plan from bw. I went an inch wider with the cab than recommended (not 'on purpose'), and used the 350's and Delta 12A's. I couldn't be happier with these.....they fit my needs perfectly. Mounting the waveguides was not a problem, had a little trial and error with the custom cutout, but no biggie. Best I recall it was about 5.25" x 12", with both ends sort of elliptical (jigsaw city). A template for the SEOS waveguide cutout would be nice for future builds. These are my first Eminence drivers, and they are a class act. T/S parameters were close to spec out of the box, and the 10.95" (11") cutout was right on the money.

I am listening to them right now outside on the lanai, and they do need room to breathe. I have them about 15' apart, toed in, and wow..... clarity and dynamics definitely prevail.....these are not for small rooms or the weak at heart. I can't see how anyone would not be happy with one of the Eminence builds...but I run subwoofers. All of the opinions about the different potential kits/baffles, etc. make me dizzy.........I was planning to settle back, drink a few, and listen to these for a while and see what other designs come forward in the coming weeks. My needs are simple, and another pair of these is probably overkill. Building the crossovers is no biggie for me, but a prefab one would be nice, and a lot of folks would jump on that.

Howard H.

your noob board looks good to me, but i don't know much about passive crossovers. i tried to follow every path and it seems to match the plan.

is the i-core choice based on cost? would an air core enhance the sound? the woofers in these two way designs play pretty high into the midrange.

also, are 5w resistors enough for the top end? you probably won't ever put that much power through them, but running resistors at even a partial load would seem like it could heat them up and change the sound.

edit: it looks like there is an erse 2.5mh 18 awg air core at p.e. for $15. i wonder if it is worth the extra 5 bucks.
http://www.parts-express.com/erse-18-gauge-air-core-inductors.cfm
Edited by LTD02 - 7/4/12 at 3:06pm

i don't think it is a tolerance issue. iron core increases inductance (actually anything inside the coil does)*, which makes them cheaper to produce. but i seem to recall "air core" inductors as what one should use for audio components, but it probably depends on how it is used. i was just curious about the choice and if the air core would be an upgrade or not, and then there is the question if one switches one component, does the whole crossover need to be redone. i don't know that either.


*this is how stop light sensors work by the way. a metal loop is put on the road and the inductance is monitored. when a car rolls into the loop, the inductance changes. that signals the computer that a car is waiting and then based on a variety of algorithms, the computer will change light.

The iron core is to reduce the dc resistance, which would change the bass more than thw core could borher the midrange. Sure ideally aircore might be a bit better but it would haveto be very thickgague to get low enoughdc resistance.

Best of allwould be active crossover.

p.s. I hate this keyboard!

thanks bw. i couldn't find the resistance on that particular i core. do you happen to know what it is?

"The iron core is to reduce the dc resistance.."

technically, the iron core increases the inductance, as a result, fewer windings are needed for a given inductance. fewer windings means less resistance. right? :-)
Edited by LTD02 - 7/4/12 at 5:37pm

right

Java,

There are different techniques and you will learn what works best for you after you get the first one or two done. Just do whatever you feel comfortable doing.

I mounted mine to 6"x9" thin scrap plywood, with a hot glue gun being my best friend. I then (industrial strength) velcro'ed them into the cabinet for easy removal. There is a rule that coils 'close together' should be on separate "planes"(?) so the magnetic flux doesn't interact.....when you look through the hole of one, you should not see the other and should be perpendicular. See how the two on the right side are mounted. One is laying flat, the other is standing up with the hole perpendicular to the other's. If you look at photos of any pre-fab crossover with multiple coils they are built that way. I'm not sure if that rule applies to an iron core, or what the minimum distance between them is so that positioning is irrelevant.

Since it is what I had on hand, I used #14 AWG for the input and woofer output, would rather have used #16. #18 AWG is all that is needed for the hf output (note the small wire size capacity on the CD's).

Since there were no 2.2 ohm resistors available when I ordered from PE, I put a .22 in series with a 2 ohm (probably unneeded). I got the last 3 ohm "standard" resistor when I ordered, and substituted a 3 ohm "non-inductive" resistor for the second crossover. My understanding is that at audio frequencies, the inductance is minimal, and that's why bw didn't spec them for use - no functional value for the extra $.

Wayne Parham has a pretty good write up about power handling concerns and the 3pi/4pi crossover designs. He uses 4x10 watt resistors (parallel) to get what he believes is a design that can take the full rated power of the woofer (600 watts for JBL 2226?) with no problems. Good idea? Yes. Absolutely required when you only have 100 watts available? Probably not. Resistors are cheap. I doubt 5 watts would be a problem for most home users but if 10 or 20 makes you feel better, go for it.

1. You're welcome.
2. Yes, bare wire as the common.
3. Built like the drawing, no L-Pad.
4. I don't know how many watts I was pumping last night, never saw the peak lights on the ART SLA-2 (200 watts/channel), and I thought I would. I do know I don't need it any louder. Only the hf section employs resistors, and at higher frequencies 20 watts is a lot. The power is distributed across the circuit. Could they be a concern? With dynamic HT, who knows....loud passages can catch you by surprise, but I don't have any worries. With more robust drivers and amps doing something crazy, maybe.

I get somewhat carried away when watching concert videos, everyone has their favorites. My neighbor came over and he was astounded, two words: clear and dynamic. He rarely stays more than a few minutes, and I had to turn it off for him to leave. Don't worry too much.. you will learn something from every experience. It is always good to research as much as possible beforehand, but at some point you make choices and go. I like taking the journey, but getting to the destination means reaping its rewards for years to come. The thing nice about DIY, you can usually re-do or re-configure at minimal cost. These DIY designers know what they are doing, and I think they all should have little donate boxes posted somewhere.....it's easy to put 30-40 hours or more into a build with a ready-made design in hand. Imagine what they go through.

Soon I hope "Eternal" becomes "No Longer A".......it is all relative anyway.

I apologize for taking this OT. what concert video were you watching?

OT for this forum, but everything from ABBA to ZZ Top would sound great, all genres.

"Wayne Parham has a pretty good write up about power handling concerns and the 3pi/4pi crossover designs."

mobeer, bad etiquette. you can't just plop that in a thread and not post a link. :-)

which one were you referring to?

I used 5W resistors largely for size and ease of use. You can of course use higher powered ones if you want or if you expect possible abuse of the setup (though in that case, I'd be more worried about expensive drivers than cheap resistors).

Keep in mind that power resistors are limited on average power (=heat) which is pretty low for hifi audio. Peaks can go to hundreds of watts (though not often!) but average? 5W averaged long enough to build up heat, in a decently efficient design would be pretty unusual, and then only a fraction of it would end up in the resistors. Not so for pro audio or musical instrument amps, where you could be playing at full tilt compressed from a single instrument nearly continuously with peak about the same as average; then heat can get up fast.

Generally, if I see signs of even a 5W resistor having gotten hot in a hifi speaker, I'm usually pretty confident that an idiot had been in charge of the volume control!

That does not look like a NPE, non polarized electrolytic cap. It looks like a regular polar electrolytic cap. It doesn't look like what your second link is. I don't think it will work. Could be wrong. How 'bout a closeup pic showing the markings?
Edited by djginwis - 7/6/12 at 12:02pm

no way is that the right cap. Mylar would be ok, but thats a polar lytic.

"Since these speakers are going in my home theater where I don't have total control (i.e., teenagers), I decided to grab some 10 watt resisters..."

ah, baloney. you just did it for that tim allen braggin' rights moment...

"i went with the super elliptical oblate spheroid 12 inch...over top of the 2512 woofer build...with the custom upgraded resister set in the crossover...yeeaaahhhhh..."



ah crap, now we'll probably have half the people going for the 'upgraded resister set' even though it isn't needed.
Edited by LTD02 - 7/6/12 at 5:09pm