Hey guys...we need a little rallying here... - Page 92

Here are some opinions (not to be confused with facts )

If I were developing another compression driver WG today, I'd do as Josh suggests and go with a super elliptical PS. (Wish Josh would have mentioned SE before I went with an elliptical mouth!)

The original sims, and subsequent measurements, seem to indicate a lower diffraction profile for the elliptical/PS. Subjectively, I easily prefer them over my earlier 80 degree OS WGs. The exact profile hasn't been publishedtrue, and it probably never will be. The time investment was so high, it feels like giving away a family heirloom. That said, it would be relatively easy to take the core concept, hone it with your own set of design tradeoffs, and build them. I did the sims with a laptop running Axi-Driver, the build by hand. A fast computer and CNC should make quick work of it.

Assuming availability with any motor and phase plug, my first choice for CD diaphragm material would be beryllium, followed by titanium nitride, then aluminumbut only if they came with a non-metal surround. Measurements provided by 18Sound show better low-end distortion with a plastic surround (midrange distortion products are more objectionable than the 2nd or 3rd harmonic of 7k).. Plain titanium is not on my radarhaven't looked at plastic diaphragms, but I suspect Josh is correct again. Since custom diaphragms/surrounds are out of my league, I'll settle for aluminum/plastic.


BTWcurrently working on taking that vertical directivity thingy a little lower in frequency

You guys might want to wait on buying certain woofers. Hopefully we can set up some type of group buy with those too. The money saved could go towards free shipping or something along those lines.


As for the compression drivers, I'm ordering the stuff this week. I'm going to do everything I can to not do preorders. But the pallet of horns and waveguides from Poland is pretty much done, which means I have to send them $$$. The last time there was about $10,000 worth on the pallet and I think there's even more this time due to a bunch of smaller items.

Preorders also stink if they go through Paypal simply because of the 3% charge, unless that's how you were going to pay anyway.

I'm not sure we'd call it preordering the compression driver, even though that's what it would help with. If someone wanted the plastic SEOS-12 and the CD's, then a preorder would sort of go towards both, then obviously no matter what happened, you'd be guaranteed the waveguides because they've already been paid for. Not sure that makes any sense at all, but I tried.

Eternal Velocity... thanks for your reply.

I knew it would'nt take very long for this discussion to start.

Anyone who spends the time and money to build speaker systems like the ones people here are building and does nothing about the acoustics of the room they are in... is like someone putting a Ferrari engine in a model T. Great engine... but you not going to go very fast or corner at all.

Great sound is a result of a great system and a great room. Most if not all rooms needs lots of acoustic problem solving... most importantly including first reflections from the floor, ceiling, and side walls. Most if not all rooms need some sort of bass absorbtion. In the midrange and high frequencies the goal is to make reflections work in your favor with acoustic reflective devices. [This is an edit of my original comment].

The problems you and A9x-308 are talking about are from the room... NOT the speaker itself or the dispersion from the waveguide. The key... is after you have built your great speakers... is to then give them a great room to play in. Thats why recording studios spend so much money on room acoustics and room design. What you are advocating is trying to solve the problem of room acoustics by changing your speaker design. Thats not the way to do it. The way to solve room acoustic problems is by fixing the room acoustic problems.

Putting high end speakers is an echo chamber was never a good idea and it still isnt. I stand behind my comment.

I have heaped praise on the SEOS waveguide in both of my comments. I believe it is a great design... but that it needs more vertical dispersion for the it's intended use... which appears to be home and studio use.

Last... I would be listening to a SEOS18 right now... if there was one for my 1.4 inch compression drivers. My hope is that if anyone decides to come out with a bigger version with lower frequency extension that they will consider wider vertical dispersion in the design... something with veritical dispersion more similar to the horizontal dispersion of the SEOS's.

Great sound is a result of a great sound system and a great room.

If you want vertical=horizontal, why wouldn't you just use a circular OS guide? The SE part of SEOS was to get the C-C closer (and to narrow the vertical, for those of us who prefer it that way) so the vertical cancellation NULLS wouldn't occur in the listening area...

Actually, what I meant was what company can actually build the passive crossovers after the design is already done.

As in assembling them for people that don't know how. I think that's pretty important so that more people can use these.

Strawman.

Give a cogent reason why along with the physics of why you believe this and the discussion might be of value. You just stating you believe it's needed with no reasoning why is not useful.

Guys, I was going to ask a simple question about the SEOS-22.

Would it make sense to possibly make it a slight bit deeper than the ratios used in the current models? Not by a huge amount, but some.

Erich...

I will be ordering a pair of your new SOES as soon as they are available. Great work.

It's exactly the way to do it if you don't have the luxury of a perfect room.

But let's say you did have a room with perfectly absorbing floor and ceiling, or whatever it is you think is perfect.

What's the point of wasting speaker output on that?

60 deg vertical coverage is perfectly adequate for seated and standing listeners at any serious listening distance, unless the room is very small, which would violate your dictum to start with an acoustically ideal room.

Breau-

I'm with A9X on this. I don't see any support for why you believe wider vertical directivity would be a positive.

The 90x60 was chosen for a number of reasons. First, it reduces C-C spacing for a wider lobe. Second, it matches the room height to width ratios of most residential rooms. Third, a narrower vertical would be chosen, but there are downsides to going shorter than about 40-50deg. IMO, 50-60deg is the sweet spot.

JBL offers their 100x100 PT horn because there are some sound reinforcement situations where wider coverage is needed. Most SR setups are chosen for a specific coverage and JBL offers a bunch of different options.


I don't know about offering assembled crossovers, but Pi does it. You could more easily have PCBs printed like what Zilch did with the Ewaves.


I'm not sure what you mean by deeper.

Anyone know where to get the PCB's printed up? Not sure those are necessarily needed, but I'd look in to getting them done if enough people thought it made sense.

As mentioned, there's a forum member that can help assemble the crossovers for people. But I don't know how long they take, or how many we'd need when the time comes. So it could be a bigger task than we realize.


It seems very important to me that I can get fully assembled crossovers so that a lot more people can use these speakers. Plus, as mentioned before, if there's a couple of super quality designs that come from this, I'm going to contact the guys in Poland to build some really sharp looking cabinets. I've got a few ideas, but the full cabinets wouldn't be very cheap. They'd go head to head with even the most expensive speakers out there though. And the full cabinets would look really sharp. That's just a thought for later down the road though.

A9X-308

I gave the reasons in the comment that you originally responded to.

I guess the question is what makes 90x90 (I presume that is what you are suggesting or are you suggesting even wider?) better than 90x60 even if the room is "perfectly treated". That is the part that I think you need to support. How is 90x90 better than 90x60 in a residential setting?

coctostan

Thats exactly right. The 100x100 is offered for smaller more intimate rooms where the "audience-listeners" are closer... like a room in your house or a recording studio... or my friends pool hall, where he has a stage 10 inches off the floor and the crowd is right in front of the band... like your home system and a recording studio system.

Wider dispersion gives better stereo imaging and soundstage... and a larger sweet spot.

For the situation where the crowd is directly in front of the band, it might make sense.

I don't know of many home systems where people sit 1-2 feet in front of and below the speakers while also needing coverage 20ft behind them. That would be bizarre.

If you take a 90x90 horn and place it at the midpoint on a 8ft wall, it will cover evenly just 4' from the speaker. What good is that? Nobody listens with their feet an nobody stand 6" from the speaker. I guess people who like to lay on the floor would get more even response, but that is meaningless.

In my HT room, I could get away with ~15 deg of vertical coverage for the seating positions but that isn't feasible for the horn. This is covering two rows of seats and aiming up slightly.

Your logical connection between wider vertical coverage and imaging and soundstage is non-existent.

Noah Katz... you said...
"But let's say you did have a room with perfectly absorbing floor and ceiling, or whatever it is you think is perfect.
What's the point of wasting speaker output on that?"


I'm assuming you are kidding?

Let's start with the imaginary scenario of listening in an anechoic chamber. In this scenario, only the sound arriving at our ears from the two speakers is heard. This means you need about 2 inches worth of sound waves at your ears. Anything else just doesn't arrive.

We have two ears, and they're not on our chin and forehead, so we need wider horizontal dispersion in an anechoic chamber for the sound from the speaker to be registered by our ears, but still only about, what, a foot worth of dispersion? Though to be honest you may not want the stereo cross talk and might choose to divide the sound for true ambiophonics.

This will give you the so called best imaging. You might consider it "headphone" imaging and maybe it's not your preference, but it's truest to the souce. It's not my preference either, mind you.

Anyways now leave the anechoic chamber, and put yourself in the room. Now you've got reflections. Reflections do many things

1) Change stereo imaging
2) Change sense of spaciousness
3) Change tonality, especially on sustained notes.

Now the thing to pay mind to, is the delay of the reflection.

The first issue, is that in most rooms we hear vertical dispersion as a VERY early reflection. The floor is almost always the first reflection out of all "first reflections".

VERY early reflections are damaging to timbre and detail.

Now let's return to the concept of our two ears. They hear reflections off the side walls as imaging cues. With wider dispersion speakers they give the illusion that the sound is coming from "outside the stereo triangle".

Now if you're doing a waveguide build, you've already sacrificed those horizontal reflections. You want imaging that's on the recording, not imaging created by the room.

That's a personal choice. The main advantage is the plus to timbre and detail.

The problem is this:

Our two ears are a lot less sensitive to these "created by the room" imaging cues when they from above or below.

So what you get if you increase vertical dispersion, is very little of the "good" of dispersion (reflections creating a wider soundstage) and a lot more of the "bad" of dispersion (damaging detail and timbre).

So all dispersion isn't good dispersion.

You want enough vertical dispersion to cover a zone. But i've never seen any reason to advocate more ceiling reflections.

Now you've said something about treatments.

The problem with treatments is this:

Reflections are what creates spaciousness.

Every time you absorb an early reflection, you're also killing late reflections.

So the deader the room, the less it feels like we're in a "huge place" and the more it seems like we're listening to loudspeakers.

Absorption is just about never the solution.

And I agree with Noah, what's the point of a speaker producing more wide angle output (dispersion), only for it to be directed into an absorption panel? It's a waste of time

That's just nonsense.

"Just diffuse it then"

Actually, that's probably the best thing to do with vertical reflections on the ceiling. But not realistic for the floor. =(

Finally after all that, there's the issue of center to center spacing.

The decision for the 60 degree coverage angle reduces it. That reduces destructive interference (more bad and unpredcitable vertical reflections) while also making the crossover easier (driver acoustic phase is less mismatched)

Eternal Velocity...

I agree... absorbtion works best for low frequncies...

Infinately variable reflection works best for midrange and high frequencies.

I looked at my comment above and I can see where some may have misundertood what I said. When I said "tame" the midgrange and high freqencies I was not refering to absorbtion but infinately variable reflection. You dont want to absorb those frequencies because you deaden the room. Some room designers have used things such as volcanic rock, large tree branches, book shelves, and mathamatically derived dispersion and reflection panels to make room reflections work in their favor. Any and all can work. But in most if not all rooms something must be done.

Dispersion is not a problem in a room with great acoustics... just the opposite. It gives the sound a more real life quality... better stereo imaging... better soundstage and better dynamics.

Great sound is a result of a great sound system and a great room.

Coctostan

I cant believe you guys can be this far off on this issue. Virtually everything that has been done in sound outside of Pro Audio has been about stereo imaging and soundstange. Dipole speakers, speakers without a baffle, speakers that radiate in 360 degrees even THX is all an attempt to make the sound more life like and realistic. Where have you been?

What is the fear of dispersion?

Vertical dispersion is.
Horizontal, is not.

[quote] Dipole speakers, speakers without a baffle,[quote]

*both of which restrict dispersion by creative dipole cancelations.


Omni speakers throw an interesting soundstage, but have serious timbral issues in all but the most perfect placements in custom rooms.


Those THX surrounds are a disaster.


Including what guys like Geddes and Parham have to say ... Anyways the SEOS is not a Pro Audio horn. It's a High Fidelity Waveguide with an intentional 90x60 dispersion pattern. High Fideltiy waveguides are intended to be crossfired and provide as close to constant directivity as possible.

Whether that's preferred or not is your choice.

I understand your position. Wide dispersion speakers can sound great properly set up. But a 90 degree dispersion ain't exactly beaming territory.

In the direction where dispersion matters, pattern control is sufficiently wide.
In the direction where dispersion hurts, pattern control is intentionally limited.

Nope.

[quote=Breau;21657750Dipole speakers, speakers without a baffle, speakers that radiate in 360 degrees even THX is all an attempt to make the sound more life like and realistic?[/QUOTE]

All of that is for *creating* a soundstage.

Short of late reflections needed for perceived spaciousness, all of those just obscure soundstage cues in the recording.

What? Assembling the crossover is the easiest part of building a speaker. It is funny how we each perceive the challenges of speaker building through the lens of our own skill set.

I know there are many that aren't comfortable building crossovers, though I'd encourage anyone who is considering it to just go for it. Soldering big crossover parts is a great project for a first time solderer, and you can always melt the solder and try again if you don't get it right the first time.

I'm not prepared to assemble tons of crossovers, but I'd be open to helping out or building a few.

-Max

So when can we expect a "place deposit for pre-order" button on the DIY Sound website?

Hopefully some of the XO designs will be able to use the ZilchLab PCB. That would make for a pretty easy build.

what?

it too me a few months to muster up the courage to finally go to radio shack and pick up a $10 solder to start putting together the crossovers for my OS speakers from Erich. lol

but i agree with you though, it was pretty darn easy when i started to solder. wish i did it sooner. for a new member, who never put together a crossover before, it seems like a daunting task watching all the parts, connectors, etc and trying to put all the pieces together. i studied the schematic for almost a week, and trying to lay the pieces on a board and see how they fit. overall, it did take me a few hours to put them together. if i can do it, anyone on this forum can.

Breau-

I hate to say it but you are a little over your head on this stuff. In a very general sense you are right that some reflections and an acoustically well prepared room are important. Somehow making the leap that we need more vertical coverage is where you are mistaken or at least offering an opinion with absolutely zero support.

Show us something that indicates any floor or ceiling reflections are beneficial. Some reasoning or support or something.

You mention dipoles. Yes, dipoles can be used to enhance imaging and soundstage. How does it do that? By controlling coverage and early reflections. It doesn't do that very well in the vertical realm though and that is a limitation of most dipole designs.

In a perfect system, you would have zero vertical reflections. The late reflections you want ideally should only be off the side walls. The reason we don't use a narrower coverage horn is because of issues with the wave shape. Ideal coverage is probably closer to 20 or 30 deg in most homes.

Beyond all of that, you are suggesting treatments on the two most difficult regions to treat, the floor and ceiling. This is more manageable in studios, but in homes very few people can adequately treat the ceiling because they are ugly and about all you can do on the floor is have thick carpet which doesn't do all that much. It is simply not practical.

-------

Concering crossover construction, I think Erich is hoping to put together what are effectively "kits". I'm guessing he would hope these would require nothing more than a screwdriver and glue. Basically you could order a waveguide, flatpack, drivers and built crossover. Then screw it together and fire it up.

For those that fear crossover building or soldering, it is really very simple. You don't even need to solder. Simple crimping and euro style barrier strips work well and allow for easy mistake correction. There are online guides on how to layout the crossover from a schematic.

Geddes had his crossovers setup to use screw down terminals for assembly. Once you have the designs you could look at getting PCBs with screw down terminals made. That way crossover assembly would just require following a layout diagram and tightening a few screws.

Those are the euro barrier strips I was referring to.



It makes assembly very easy. To make it even easier a simple PDF that positions the components so the user knows where to put everything could be made. I think lots of people struggle with transferring the schematic to a layout.

Magnesium oxidizes with humidity, and CDs are often used outdoors. Also it is extremely flammable, so a shorted VC or something could be a fire risk.

Erich, thanks for making the plastic SEOS-12s. I will be ordering two once they appear on your website, to use with my 12" Delites.
Thanks!
Rich

Coctostan
"This is more manageable in studios, but in homes very few people can adequately treat the ceiling because they are ugly and about all you can do on the floor is have thick carpet which doesn't do all that much. It is simply not practical."


Ugly ? Of all the recording studio's and home studio's I've been in, no one ever refered to any them as being ugly... in fact all comments about their appearance was exactly the opposite. Beauty is in the eye of the beholder.

Not practical ? If anyone took that advice then none of us would be building our own speakers.

My original comment that started this was as much a question as anything. I was curious about any designs for the SEOS in the future. You all have answered my questions. Appreciate it.

Once again... great work Erich and all involved.