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Hey guys...we need a little rallying here... - Page 171

post #5101 of 9857
Quote:
Originally Posted by bwaslo View Post

Cosmetically, I like the roundovers. Your cabinet size, though, will restrict you to roundovers less than .1.5 inches radius, not large enough to do much at t he sides of the baffle. It would probably help at the top of the baffle, though, as the waveguide loses vertical directivity higher in frequecy.

Hi Bill,

 

I'm routing by hand, I don't own a table.  A 3/4" radius is the largest i'm brave enough to spin on a handheld router so, I guess I'll mull over the top/bottom roundovers.  I'm actaully thinking more about finish options for the cabs.  Veneer is really a nice touch for speakers but roundovers on four corners of the front baffle takes the difficulty up a notch above my veneering skills.  Roundovers on two edges might be doable though.......

 

Admitting ignorance here:  Are the baffle diffraction issues only problematic off axis?  IOW, since it loses directivity up higher on the vertical axis, are the baffle diffraction effects only present off axis, or on axis as well?  I really don't care how flat the response is at my feet or up at the projector......  wink.gif

post #5102 of 9857
Nick,

With a 3/4" roundover you should have any issues with veneering. I just did a pair of statements and they're narrower than the SEOS speakers. That being said, my roundovers are just on the sides and not on the top or bottom. I did have assistance with a friend, but mainly because those speakers are so large and heavy.
post #5103 of 9857
Quote:
Originally Posted by NicksHitachi View Post

Admitting ignorance here:  Are the baffle diffraction issues only problematic off axis?  IOW, since it loses directivity up higher on the vertical axis, are the baffle diffraction effects only present off axis, or on axis as well?  I really don't care how flat the response is at my feet or up at the projector......  wink.gif

The diffraction affects all axis, but affects them all differently.

With the large SEOS12 designs, there's hardly any diffraction going on. A lot of what you read about diffraction stems from people using flush dome tweeters. I've used them lots, and they're diffraction nightmares. dlr (tech talk poster) has spent a lot of time on this using foam and all kinds of tricks to mitigate diffraction. But if there isn't any or very little sound "hitting" the baffle edge, then there's no diffraction to worry about. If you use the driver at wavelengths smaller than the baffle dimensions and below any directivity control then you'll have diffraction. The only time I see that happening is with small waveguides.

What ever you do is going to mostly be cosmetic. I do it to. Not on my test boxes mind you, to save time. But on anything I keep permanently I put a round over on it.
post #5104 of 9857
Quote:
Originally Posted by fakamada View Post

Is BSC just built into the crossover to tilt down the rosponse above 100hz ?

I checked how Zilch used to deal with this. Sometimes he incorporated BSC into crossover by choosing bigger coil. In his designs Low-pass coil value was beetween 2.5mH and 4.5mh (!)
post #5105 of 9857

Also don't forget to add woofer inductance......  wink.gif

post #5106 of 9857
I've attached a graph from JBs Diffraction and Boundary Simulator to illustrate what you've been discussing, modelling a 16" x22" baffle with 12" woofer placed just below where the SEOS would be

Baffle step is that 6 db ramp/step with some ringing/overshoot that starts to be apparent at 100 hz and peaks at 550 hz or so

.

Sufficiently large roundovers can make those ripples past 1 Khz go away. A 3/4" roundover takes care of the ripple past 2 khz. Eyeballing it, a 2.25" roundover reduces the undershoot just past 1 Khz to about .4 db. these ripples are small to begin with and at or above crossover so you can see why roundover is considered optional.

Reflections from nearby floor and walls will add additional ripple to it above 100 hz while boosting the base below 100 hz and resulting in a cancellation null for nearwall situations between 125 and 275 hz.. Other nulls come from floor and ceiling. these nulls are the reason for flanking subs (as we all know)

What also happens is that if the woofer has more than 1 mh or so of Le, its output will start to roll off before 1 Khz changing the step function in the graph to more of a hump. Such a hump would be too pronounced to be ignored and thus likely taken care of in the crossover.

What the speaker/crossover designer doesn't address, you can take care of with a pro-amp with DSP

Jack
post #5107 of 9857
Quote:
Originally Posted by Erich H View Post

I've been trying to think of names for some of the currently unnamed speakers. One that crossed my mind today was "Bipolar".

I like it, but it's sure to cause confusion with bipolar speakers, which radiate in-phase from front and back.

But staying with the concept, how about the Schiz Series?
Quote:
Originally Posted by tuxedocivic View Post

With the large SEOS12 designs, there's hardly any diffraction going on...

That makes sense, but then why does Geddes make such a big deal about it?
post #5108 of 9857
Thread Starter 
"That makes sense, but then why does Geddes make such a big deal about it?"

i'd be curious to know as well. at 90 degrees off axis, the spl is down 20db which is down 99% relative to on-axis energy. jbl has sharp corners at the edges of the horn on the k2 and the everest and they seem to work okay. wayne parham apparently did some testing and concluded that roundovers didn't make any difference on his 4pi's.
post #5109 of 9857
He does? His speakers have a (what looks to be) 3/4 round over and that's it. I know he makes a big deal out of diffraction within the horn, I think. I don't follow him to closely.
post #5110 of 9857
I googled "audibility of diffraction" and found Linkwitz's interesting post on diffraction from baffle edges:

http://www.linkwitzlab.com/diffraction.htm

where he says its endlessly debated and presents data and analysis and concludes:

"While I try to minimize visible diffraction ripples in the frequency response for good measure, I have no evidence that even strong diffraction effects have significant audible consequences, except for the transition region, the "baffle step", where radiation goes from omni-directional to forward firing. Note that there is no baffle step at 90 degrees off-axis, and boosting low frequencies for a flat on-axis response will add to the downward sloping trend of the frequency response off-axis. This causes a spectral imbalance of the reverberant sound field in the room and is a major reason why I prefer dipole radiators. Diffraction effects are always spatially localized and a slight shift in listening position will change their magnitude. While the "baffle step" cannot be avoided, the additional higher frequency ripples can be easily reduced to a magnitude that is much smaller than the first arriving direct sound, by simply optimizing the proportions of a rectangular baffle. The absolute width of a cabinet is not the critical parameter that many people think it is. Much is hypothesized, little is proven and much is overrated when it comes to diffraction"

Regardless of whether diffraction is audible or not, since many believe it is, it's smart marketing to round the cabinet edges. But the real key to success is likely choosing the right amount of baffle step comepensation for the best balance between on-axis response and power response. Geddes makes a point of noting his speakers are optimized for flat at 22 degrees off axis, consistent with them being used toed in.

Jack
post #5111 of 9857
Thread Starter 
nice find. as for the 22 degree bit, that is also sort of required with axisymmetric horns as they end up with a hole in the on-axis frequency response.

have the kits been announced yet or is the information still embargoed? java's build (2.5 cubic footer sealed, iirc) really looks good in the photos as well as in model. a flat pack version of that one would surely be popular (now that neodymium prices have calmed down), particularly once bwaslo's crossover design finds its way on to prebuilt boards. that's really getting into the area where just about anybody should be able assemble and finish a set.
post #5112 of 9857
The Delatlites just came back in stock, so I can now get those ready to go. The kit without the box came in about $20 less than buying all the parts separately, and including shipping. I was hoping for less, but Paypal and packaging is about $11 and I'm figuring shipping at $17. If it wasn't for that, it would have been $48 less than buying everything separate.

Actually, I guess you can get everything, including the front baffle, shipped for less than the parts would normally cost. I need to figure out a better way to list all these options so it doesn't look so confusing.


seos_deltalite12.jpg
Edited by Erich H - 8/26/12 at 3:53pm
post #5113 of 9857
This thread is making it difficult to wait for my house to be built smile.gif Looking forward to the 15" and 18" kits smile.gif
post #5114 of 9857
Damn,

Erich's photo 2 posts above - is pure "sawdust eye candy" smile.gif
I need to build me some of these!
post #5115 of 9857
Are some of the bigger horns coming on the next shipment? Also, will the prices drop down at all? Currently the Seos 18 is 5x the cost of the Seos 12.
post #5116 of 9857
That's because seos 12 is in plastic. Would require another huge investment to get seos18 in plastic, expensive molds have to be made and minimums must be met. don't think it's likely to happen.
post #5117 of 9857
Thx, and just for clarification, was the not likely to happen in regards to them coming at all or just the price coming down?
post #5118 of 9857
Fiberglass and concrete ones are avail (but shipping from poland is pricy, which is much of the cost)
post #5119 of 9857
Gotcha
post #5120 of 9857
So, when will I be able to put down an order for some 15" concretes? I also wonder if there is any designers out there working on TD15M-SEOS15 combo?
post #5121 of 9857
I have that combo, but used a minidsp active xover with it. Sometime back I simmed a passive xover for them, though I didn't build it. It was posted in tbis thread sometime last year, I think.
post #5122 of 9857
I recall seeing some passive XO, but I cant seem to find it now. Here are some that I did found however:

http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here/3000#post_21742795
http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here/3030#post_21743881

And of course:
http://www.avsforum.com/t/1291022/hey-guys-we-need-a-little-rallying-here/3090#post_21763563
smile.gif

Also, coctostan mentioned he would build a XO for the TD15M when the drivers from the group buy ships out.
post #5123 of 9857
You can order the poured concrete models right now for any size. I will list the price, but it could change a little once I pay for shipping the pallet here. I just try to break even.

It will be difficult to guesstimate exact figures for the cheaper items because I don't know how many things will fit on one pallet.

For example, if the poured SEOS-15 was $50 and I figured $10 extra for shipping from Poland, that might work okay if there are other more expensive items on the pallet. But if they can only get 150 on the pallet after someone else orders a couple bigger horns, it won't cover all the shipping and customs fees. The first 3 pallets averaged between $1800 - $1950 when all was said and done.

I'm also going to have to start taking deposits because people seem to enjoy placing orders, then cancelling in a few weeks or a month later.....or when I get them, they never reply to my emails so I'm stuck with their stuff. It happened yet again on the pallet were I have about $1500 worth of stuff to add to the $2500 from the previous pallet.



Here's something strange. That $2500 order has now been sitting here for 1 year. Roughly 5 months ago the guy sent me about $500 through Paypal. But he still didn't give me his phone number or address. I've emailed him many times to see if he's going to pay the rest, or if I should ship $500 worth of his order. I haven't heard anything in 5 months. So I've got no way to ship anything, and don't know how long I should wait. Crazy.
Edited by Erich H - 8/28/12 at 7:14am
post #5124 of 9857
The $500 is yours imo, dispute period is LONG GONE.

List those goodies on diysoundgroup so people can buy em up
post #5125 of 9857
Yeah really. How bizarre. Any black fiberglass seos 10's?biggrin.gif
post #5126 of 9857
Quote:
Originally Posted by Erich H View Post

You can order the poured concrete models right now for any size. I will list the price, but it could change a little once I pay for shipping the pallet here. I just try to break even.

Erich, where do I preorder? Send you a mail? Have been looking at your site but can only find the fiberglass-versions.
post #5127 of 9857
I'll have to get photos up for the poured models. They look identical from the front of course.

Without really crunching numbers, the price list looks to be close to this:

SEOS models:

6- $28
8- $35
10- $40
12- $50
15- $60
18- $69

The one piece front panels will be available in some sizes too. They're kind of expensive, but they look incredible and pictures don't do them justice.

That's only adding between $7 and $10 to each one to cover shipping a pallet from Poland to the US. As mentioned though, the problem is obvious. That additional money doesn't add very much to the price of pallet shipping. 100 of them would only put about $900 towards shipping from Poland. So that would only pay for 50% of the costs. They do add more to the larger horns themselves to help cover shipping, but the smaller items are hard to figure. That's why it hasn't been done yet......because I want to make sure I break even. I thought about buying a bunch and figuring it all out when they arrived, but that's a lot of money to put out when I don't know what you guys might want. And I've been burned on all the other group buys except the first one.

Keep in mind, I'm also using their pricing figures from quite a while ago. Prices for the fiberglass stuff has gone up a few times since I started helping with these, so I will have to ask to get current rates.


I can say this: If you want any of these, I wouldn't wait for the pallet after this current one. My guess is that once these poured models get out there, prices will go up significantly. That's what happened with the Iwata-300. At first I think they were about $235 each, after that first pallet, they hopped up to over $300. Then $375. On the last pallet they are suppose to be $430 (each) because of the metal flange on the back. But shipping was covered to the point where I broke even at $395, which is what I sold them for. They clearly tell me how much I should list everything at. But I list them to break even. Not sure how much longer they will let that go before just raising the price on their end to get that extra savings. They haven't told me the price I should list the SEOS poured models at because they are somewhat new. Another forum member thought these would likely jump up by a significant margin at some point. I'm sure you get the idea what I'm talking about. Basically, don't wait once I post them because the pallet will fill fast and I'm going to make sure the prices get locked in.
post #5128 of 9857
Quote:
Originally Posted by omegaslast View Post

The $500 is yours imo, dispute period is LONG GONE.
List those goodies on diysoundgroup so people can buy em up

+1
post #5129 of 9857
Hey Erich.

Any updates on this design?

#9. A&E speaker. Still waiting approval.
post #5130 of 9857
Quote:
Originally Posted by smokarz View Post

Hey Erich.
Any updates on this design?
#9. A&E speaker. Still waiting approval.

I sent bwaslo a driver this week and should get to his place on Friday. That being said, he's got a lot on his plate, so it could be a while before he has time to work with it. I don't know if Erich is having someone else work on anything. I sent John at AE a PM, ,but probably should have emailed him about sending bwaslo a phase plug.

Thanks bwaslo and Erich for working on this driver, I really appreciate.


Peter
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