Hey guys...we need a little rallying here... - Page 93

Yes, I took your ideas as something to look at for the future 22" models, not necessarily the current models. The problem I see with changing the current design basically has to do with what you see in this thread....lots of extremely smart guys wondering why change it when these were designed with a certain goal in mind.....and they met that exact goal perfectly.

Your goal is slightly different, which would require a different shape.....and that shape would no longer meet what we were after here.

So in reality, to make the changes, we'd have to make new molds in an untested design. Granted that the outcome can be predicted pretty good, but the cost of design, mold, and parts might not make it the best idea if others aren't interested in ordering enough to cover the costs.

I noticed you said "recording studios and home studios". That might be a different use case where some listeners will sit very close to the front wall and some further away. The SEOS is first and foremost designed for home audio and home theater use. Yes, ceiling treatments do fit the aesthetic of recording studios (home or pro), but not most home living rooms, media rooms or dedicated home.

Given all of that, there is still no benefit to having wider vertical coverage than the coverage you need. In other words, you want constant controlled minimally wide vertical coverage for your case. There is no psychoacoustic benefit to ceiling/floor reflections, none.

Maybe your studio case requires a different coverage (I have no involvement in recording studio designs). Do you have any references to controlled directivity speakers with wide vertical dispersion that are used in home (HT or 2-channel) or recording studios? I'm aware of the 100x100 JBL PT wg, but its purpose is SR, not home or studio use.

There are a few companies we use for prototypes at work that will provide fully populated PCB assemblies. Give them the Gerbers and BOM, and you'll get back a box of finished product.

It might be difficult to hit your cost targets though - what kind of quantities were you thinking? For anything done in America, you're usually looking at a few grand in setup costs on top of the materials and extra labor.

I think it would be more cost effective to have a parts kit (bare PCB + components) and then have an upcharge for people that want an assembled xover.

Anyways, if you're interested let me know. I've had smaller runs like this going through my house in the past and I might be able to pull in some favors (since some of these companies are run by audio freaks too).

Are you saying there is no benefit to increasing the density of the semi-reverberant decay?

Here's a place that sells them for a good price -- but you can even buy them at Home Depot if you need them in a hurry:
http://www.allelectronics.com/index....+block&x=0&y=0

I used some of those for the input/outputs on my Econowave crossovers, though I soldered the rest:


This post shows some crossovers that use euro terminal blocks for all the connections:
http://www.diyaudio.com/forums/multi...ml#post1604975


Agreed. I think this is a really smart goal that we should shoot for to help people build their own. I'd be happy to do a layout from a schematic and create a diagram.

-Max

PCBs are probably more trouble than they're worth. If people need/want to source different brand parts then the parts placement and spacing can be wrong.

Much simpler is a simple piece of scrap wood and some terminal strips like these.



Whoever designs the xover can lay out the parts placement and take some photos. The builder can then tweak the spacings to suit the components they use as well as holes to cable tie the components to the board for support.
EDIT: just saw #2765 and that is similar to what I'm describing. The chocalte block terminal strips are easy to use too, but are harder to find in larger sizes to suit bigger conductors.

The terminal strips are available in a wide range of terminals and are available easily probably anywhere in the world.

If someone in Oz wants a passive xover soldered and they can't do it them self, I'd do it for free, if they had all the bits shipped to me, and paid for the shipping of the completed unit to their home. I can also crimp anything from very small to any cable that is likely to be used in a home.

You gave opinion and a desire for something different. I was hoping for something factual or technical as a reasoning.

So far you've been given at least two excellent reasons for narrow vertical dispersion: C-C spacing and lack of illumination of the floor and ceiling. I see nothing desirable about doing the latter and then needing to add treatments to ameliorate it when you can avoid the issue in the first place, especially for nearfield listening.

I believe it was Don Davis that was involved with a somewhat recent Nashville studio build....it was a bit intense with 4 ft skyline diffusers everywhere, but the thought experiment was comparing a studio with the typical ITD and substantial Haas Kicker to a monitoring environment with no Haas kicker and the decay starting immediately ~20dB down.

I wasn't there, but all the reports were nothing but positive. It's been a while since I read the article, but the claim was that it sounded better because the semi-reverberant decay was more dense.

REW provides the ETC....how come that is never shared by all the acoustics experts on the forum?

Yes to everything there. A PDF with positioning will make things easy enough, and with terminal blocks one doesn't need to solder.


People are expecting to start building speakers in 2014 or so?

Not me......I'll be using the Deltalight 12's. Bass bins are done as well as raw 2cuft sealed boxes for the Deltalights. I want to work off of in box measurements as I suspect a box induced hump or two. SEOS 12's will be in separate enclosures containing the XO boards. Thinking of doing a slide out chassis using aluminum heatsink that I picked up from a salvage place.

Is this what you are thinking off?

Directivity of such hybrid contour truncated (without rollback), 2" driver with Fs=500Hz.

Are you planning on doing your own crossover? I think Pete S is going to use the 12" Deltalites when he designs around the SEOS-12 as well.

Interesting discussion on horizontal and vertical dispersion. It's something I've had to consider with my Synergy horn builds.

One aspect that should not be forgotten is how low pattern control can be maintained. As you narrow the dispersion, you also start to lose the ability to extend a constant beamwidth down low. With my S2 which had 90 x 40 dispersion and was 1m wide, I was able to get a constant beamwidth horizontally down to 280 Hz! However, vertically, totally different story.

So a wider coverage angle means maintaining a constant beamwidth to a lower frequency. That is a reason to consider wider dispersion than you might have otherwise wanted. A 40 degree vertical helps with c-c distance and up high it gives narrower dispersion, but lower down you get pattern flip where the dispersion in the midrange becomes wider due to the mouth size and the loss of pattern control.

Maybe the SEOS-22 like this:





I'm embarrassed to post my following PhotoShop skills:

jzagaja, I know I ruined your nice computer drawing in the lower left corner, but that is about as good as I can do. You know my drawing skills are really bad!

JMLC (exponential) roundover can be approximated by 8" circular roundover. Without roundover directivity control limit is 400Hz, driver parameters (TAD 2001):

Sd = 18,10 cm²
Cms = 1,60E-04 m/N
Mmd = 1,60 gm
Re = 6,30 ohms
Bl = 7,20 tesla.m
Rms = 2,72 newton.sec/m
Le = 0,06 millihenrys
Fs = 315hz
Qms = 1.164
Qes = 0.305

JMLC roundover seems most uniform.

The roundover I posted in the first drawing was the JMLC. I just stopped the contour where I thought it would lay on the baffle.

The second "photoshopped" picture is ugly. I was just seeing what the SEOS would look like with bigger roundovers, but staying with a rectangle shape. Obviously those aren't the correct roundovers on drawing #2.

I'm not suggesting that. I'm suggesting that energy reflected off the floor and ceiling should be minimized. Of course if you could design a room with adequate floor and ceiling treatments in a home there might be some benefit, but that is still questionable. I've seen very few homes with ceiling treatments and I'm not even certain how you could treat the floor assuming the floor between the speakers and listeners remains a usable space.

It isn't like a 40-60deg coverage horn means there is zero energy being reflected by the floor and ceiling. It means that it is going be attenuated which is good. It is difficult to make floor and ceiling reflections late which would be better.

I subscribe to the idea that late reflections are good reflections and if they can't be late though should be attenuated. Obviously that is very general, but that is basically how I look at it.

Then you have the issues of multi-channel vs 2-channel and how that should be treated. BTW, I'm only referring to the media room/HT/2-channel application. I have no qualifications or experience in the recording studio realm. It is definitely different although the basic principles do apply.

PaulSpencer-

I mentioned earlier that it would be ideal to have no coverage beyond what is needed in the vertical which is probably no more than 20deg in most homes. Of course that is not practical partly for the reason you mentioned where a narrower pattern needs less width or height but more depth than its wider counterpart. I think that 90x50 or 90x60 is about the best compromise between the ability to hold pattern in the along both axes. It is no coincidence that most horns are somewhere around 90x40 to 90x60

Jzagaja-

That is pretty much what I was thinking with the JMLC or an approximation of it creating a massive roundover and directivity more slowly collapsing from 180deg to 90deg from 500hz to 1000hz. Holding 90deg pattern that low is not important. Below 1khz, Id simply want the pseudo-JMLC's horn loading effect.

Do you happen to have an Axidriver model with a 1.4" driver instead of the 2" driver? It should show better directivity past 7khz.

This would be similar to the 18Sound XT1464 but with wider horizontal directivity which I think is beneficial in the home. It would obviously be a fair amount wider, but not as deep.

I believe the 18Sound NSD1480N has an exit angle of 10deg. I'd like to find out what the 18Sound 1460's are and what the Radian 1.4" drivers are as well. IMO those are going to be the best drivers for this application. The Radian 636PB is only $200 in the US so that makes this very feasible.

IMO, this will be a better setup than the JBL 4722-HF (the horn and CD portion of the JBL ScreenArray). That runs ~$700, has the unwanted screen compensation, it is 30" wide and you are stuck with a titanium phragm. The Radian plus this horn should be be less than the JBL combo, in a more manageable package with hopefully fewer warts.

Seos-24 1.4".

1460A is also 10 degrees. Never got an answer from Radian.

That looks pretty good to me. Anybody else have an opinion?


Thanks Paul. I just emailed Radian. I spoke them last Thursday about their 1" drivers and they are 11.4deg which will work with the 1" SEOS horns. I haven't heard the Radians, but I'd like to. They use a hybrid mylar surround with aluminum diaphragm similar to 18Sound. At $135 they are about the same price as the 4550 and DE250. Radian also specs them to play down to 800hz FWIW.

Hopefully the Radian 1.4" drivers are close to 10deg so we can have this designed for a range of different drivers like the 1" SEOS.

Hopefully the

BIG NEWS on the 1" BA compression driver I've been working on. As mentioned BWaslo named it the BA driver simply because it's a Big Asz driver! About twice the size of the DE250, but still a 1".

Today we did testing on some of the new stuff I just happen to have, along with some modified drivers, custom drivers, and different diaphragms, etc, etc. Lots of testing, lots of diaphragm switching. And of course, the modified BA has gotten closer to the finish line.


I believe we have a real winner here. I was able to mount it to the SEOS-18 properly this time (but I still think I can do better).


This test is with no crossover, just a cap blocking the lower frequencies so we don't damage the drivers. Actually, now that I think about it we probably should have left that off for these. Oh well, here's the photo. Smoothing - 1/24th

Astonishing freq response! Nice work Bill and Erich!

Very nice!!!

That BA driver looks it could work low enough to mate well with quality 15" drivers - I like!

JP

LTD02, I only have the frequency curves like I posted. There's still one more thing I'd like to change before I'd consider the driver ready for prime time. Then we'll do some more testing.


Later this week I'll hook the BA up to the SEOS-15 just to see what it can do. But we have to keep in mind that they're twice the size of the DE250 and weigh twice as much too. I posted this earlier, but here it is again.

It definitely won't have any problems at all crossing with a 15" woofer. The DE250 can do that, and these go even lower.

What is the distance from WG to microphone? VC diameter? Do you have a cross sectional drawing of the phase plug?