Help me decide: OB with Seas C18 or with Neo10/Neo3

[sfdoddsy]

I have a pair of Seas Excel C18s, a set of BG Neo3/Neo10s, and assorted bass drivers.

I want to build another OB with high WAF.

I can't decide between using the C18s or the BGs.

The C18s will give me a wider spread of sound because they are coaxes. The BGs can be coaxed into being true dipoles over a larger range.

Which would you build?

Or just buy something else and see what happens?

The Aurum Cantus AST tempts me.

[AJINFLA]

Both should have baffle shapes independent of the bass sections. Neither should be run below 200hz (maybe 250-400 depending).
Build the bass section mock up first, square away <300hz ish, then build a "top" section with each, optimize, see which fits your ears/room best.
The C18 is a monopole over a large swath. The Neo3 can be dipole, so there should be a pretty significant difference in rooms not anechoic.

btw, still can't find those opposed u baffle measurements (2012) and the test boxes are buried too deep in storage to dig out right now.

[Scottg]

I want to say Neo10/3 - but have a hard time doing that considering the vertical "window" limitation of the 10.

With the *right waveguide (and cut-in for the 10), the Neo 3 would work well, but really you need something that will extend lower in freq. to get the best integration with the Neo 10.

Maybe the AST tempting you is a good thing, at least in regard to the Neo 10.


*wide and fairly shallow with the Neo 10 extending into it nearing the Neo 3.

[JonMarsh]

I think that might be the Arum heil like tweeter that has a consistency issue- seems I recall seeing a post about a builder doing one of Curt’s designs, and the tweeter response just didn’t match up to the original design.

I could be mistaken and it’s another model, but I’d do a little checking before shelling out any moolah.

I like AJ’s development path concept.

[Juhazi]

Yes, considering OB/dipole, a coaxial just doesn't work abve 2kHz. You would need a backside auxiliary tweeter to get smoothish power response.

[sfdoddsy]

I did some very quick and very very dirty test baffles based on what my darling wife may agree to.

After listening and measuring, the C18 tickles my aural pleasure the most. The vertical directivity of the Neos is the big issue. I can EQ the response, but not that.

Plus they require a much taller baffle.

As mentioned above, the C18 isn't dipole over as much of the range as the Neos with staggered baffles. But after years of experimenting along the lines of SL and JK's diminishing baffle dipoles I'm not 100% convinced that quest justifies the complexity.

And there is no way I can get away with an LX521 in the lounge.

I initially did a variation of a previous build using separate sealed boundary woofers to meet the 250-300Hz the C18 can get down to (just) but to my surprise the opposed U baffle also has promise in a much more compact form.

[Zvu]

I did some very quick and very very dirty test baffles based on what my darling wife may agree to...

Unless you are making speakers for you wife, don't ask for her acceptance. Fulfill acoustical demands of that loudspeaker.

[Scottg]

-spoken like a bachelor. :W


Actually the best way to "get around" this problem is getting her help with all of it: make your hobby her hobby. ..otherwise it's just seen as a stupid expense that takes up space and is ugly. :roll:

[Scottg]

The vertical directivity of the Neos is the big issue. I can EQ the response, but not that.

..yup. :cry:

You could also *angle the drivers for polar integration, but even then the vertical widow will be pretty narrow, and it's still going to be 1ft "stick" rising above whatever midbass support is below it.


*but baffle complexity goes up with that, even if the "baffle" is just a support mechanism for the drivers.

[Zvu]

-spoken like a bachelor. :W


Actually the best way to "get around" this problem is getting her help with all of it: make your hobby her hobby. ..otherwise it's just seen as a stupid expense that takes up space and is ugly. :roll:

OT:

In relationship for 13 years now - 6 of that in marriage and two children: 4 and 2. With that same woman of course.

LX521 aren't ugly. If someone says they are - that's opinion anyone is entitled to. Do i erase mine because of hers or is it a two way street ?

My wife totally understands my passion for loudspeakers because she has passion of her own. When i told her few years back that i want to make something like JBL 4355 but with modern drivers all she said was - can i choose the color ? I wouldn't mind whatever she does - i listen to music almost exclusively in the dark

[Juhazi]

With home hifi, I don't think that vertical lobing is a problem. At least I can't hear anything disturbing with multi-way speakers at normal listening distance 2-3 meters playing pink noise. Reviewers of eg. Magico or Wilson speakers don't hear problems either with music.
But in nearfield (1m) a coaxial sounds super fine, I would recommend those as pc-desktop speakers or mixing desk nearfield monitors.

+/- 10dg at 2 meters is roughly 40cm

[Scottg]

My wife totally understands my passion for loudspeakers because she has passion of her own.

-sometimes the perceived "passion" is interior design, with a definite aesthetic that doesn't allow for speakers that enthusiasts would like to have. Sort of a "butting heads" result with cross-purpose "passions".

Of course "man cave" is a solution in this situation. :P (..though I have seen occasions where they even wanted control over the aesthetic of the "man cave"; solution: new wife.) 8O :W

-yeah, not everyone is going to have an understanding spouse. ops:

[Scottg]

+/- 10dg at 2 meters is roughly 40cm

-you can go out to about 18 degrees without much pressure loss vertically <2kHz. I think the real problem is a passive design and crossing-over the Neo 3 around that freq. while still getting a good sounding result. ..maybe a Cauer around 1.7?

[Jim Holtz]

-you can go out to about 18 degrees without much pressure loss vertically <2kHz. I think the real problem is a passive design and crossing-over the Neo 3 around that freq. while still getting a good sounding result. ..maybe a Cauer around 1.7?

Actually, Dennis Murphy successfully crossed the Neo3 passively at 2K more than a few years ago. I've not heard it but I can say, I've never heard a bad sounding speaker Dennis designed. His voicing is excellent.

Jim

[Scottg]

..was it as a dipole? (..and particularly one with almost no baffle to speak of?)

[Jim Holtz]

..was it as a dipole? (..and particularly one with almost no baffle to speak of?)

No, it was a conventional ported cabinet. I was just offering Dennis design as a reference point.

Jim

[Scottg]

..actually I was referring to the Neo 3 (with the back removed). It extends the lower freq. response, but in general distortion goes way up and does so higher in freq.. Plus, you have to contend with the pressure loss. ..sort of a "double whammy" to using the Neo 3 like that. ops: I think Juhazi (..see his pic.) gets away with it because it's a DSP active design with very steep filters. (..I'm also not sure the Neo 8 is quite as vertically directive as the 10.)

[Juhazi]

Actually Neo3 holds up extremely well, Neo10 low end is more in trouble. I have LR2 topology mostly, but LR4 is also ready for the "audiophool" friends who crank up volume!

https://photos.app.goo.gl/9qtxDZfZYhda3L5fA

[Scottg]

-even the low order slope in your graphs is still about -26 db from the average at 1.5 kHz. So it's not surprising that it holds up well in this situation.

..but verticals do suffer in comparison to a design with a crossover near 1.7 kHz. ..and some people are more aware of this than others (..I can't stand most of the MTM designs I've heard because of vertical "suck-out" - even when listening within the reference "window").




(..btw, nice use of the omnimic's polars!)

[Juhazi]

Thx, I transported REW measurements to unregistered version of OMNImic, it just took some trials to find right format!

LR2 slopes are practically elliptic/duelund acoustically - get steeper way past xo point.

Vertical lobing depends on xo topology very much. I have had tens of different xo versions, but never have I heard lobing in normal listening situations. -15deg means below my waterline when sitting and +15 hits my ears when I stand at spot. With dsp it is easy to aim the main lobe by adjusting delay of the tweeter. Dipoles radiate so much ambient sound that direct/reflected ratio is low at over 2m distance - it helps too.

Actually I was conserned about setting xo above 3kHz, but it sounded fine. Even 4kHz LR2 is ok! LR4 gives higher Q for the nulling effect.

[Scottg]

Thx, I transported REW measurements to unregistered version of OMNImic, it just took some trials to find right format!

-which is?

[Juhazi]

I guess it was "Export measurement as text" and I had to delete first two lines from the files created by REW. Before export I had to set gating and smoothing. File name must contain number of off-axis angle. Without +/- prefix OMNImic uses same files for L and R.The files are on my old computer...
The unregistered version cannot save it's own measurements.

ARTA can create directivity spectrograms too, but takes more time to learn that I can give... dumbass!

I measured +/- 15deg verticals again and listened, and I can clearly hear the change in pink noise sound when I stand up! Far off-axis balance is however ok, with some loss of treble of course! All LR2 xos, MT at 3.6kHz. With dsp it is easy to set different topologies, Minidsp 4x10HD has 4 presets.

[sfdoddsy]

The side mounted woofers are a no go. I did some proper measurements today.

The output is lower with two drivers than one in a regular U frame, and no radiation advantage I could see.

Drivers were RS225s in a 30 x 30 x 30 frame. No top.

[AJINFLA]

Juha, are you using a Neo 8 or neo 10 there?

Steve, you're going to force me to dig out that box despite my backyard resembling a pond. Your baffle is 30x30x3?? What is the 3? No top means you have 2 opposing dipoles, almost like a quadrupole. I would have suggested a tall narrow baffle similar to what overall "WAF" config you had in mind...
Are you measuring from same distance to front of baffle?

[sfdoddsy]

Sorry, 30 x 30 x 30 U frame. Same distance.

The results I got were very close to what Edge predicted.

There's no top because the layout I had in mind didn't have room for one.

But I can plop one on and see what happens.

[Juhazi]

AJINFLA, I have Neo8 and Neo3.
Neo10 would have been better for me but I couldn't find those way back then.

[sfdoddsy]

Well, I've done a bit fiddling, listening and measuring and decided to go fully active with the Neo 3 and Neo 10 in a stepped perspex baffle.

This is the test baffle. I'm currently using sealed Peerless SLS in boxes I had lying around below 300Hz, but may go OB with them too.

[Juhazi]

Looking good! (=transparent ) For final version you can try to get M and T closer vertically. Angled shoulders in the baffle? Any measurements done yet?

[sfdoddsy]

Looking good! (=transparent ) For final version you can try to get M and T closer vertically. Angled shoulders in the baffle? Any measurements done yet?

The perspex baffle is actually an old one I had hanging around for a different tweeter, so I would indeed be nudging the Neo3 and Neo10 closer together for the final one.

However, I flop whilst listening so my ears are at about the level of the Neo10. I did some verticals and in the narrow window of my head lolled and perked up there appears to be few issues.

I have heaps of measurements, but in all honesty they weren’t significantly different from my last speaker using the same drivers in a trapezoid baffle. The stepped baffle has a few more ripples up close, but the amount of EQ required is similar.

Off-axis measures slightly more dipolar, but it could easily be measurement or measurer error.

I’m still tweaking the MiniDSP settings so am happy to do any measurement you’d like.

[Juhazi]

Oh nothing specific in my mind. Here is Edge sim of on- and off-axis respones roughly 20 and 40deg

[sfdoddsy]

That's not far off what I got with my Edge sim and my measurements (the actual baffle width is 275mm). The dipole peak was a tad higher and a bit lower in intensity. A similar MiniDSP cut and then 12db boost as I used with my previous OBs has the Neo10 flattish to 100Hz or so.

I cross to the bass drivers at 300.

The sims for the tweeter were less useful. Both the sensitivity and the FR were wonky.

I imagine it would quite tricky to blend them with passive crossovers.

I've tried crossing my pair passively before and don't have the skill or patience to do it properly.

Since I have adequate amp and DSP capacity it is just much easier to go that way.

[sfdoddsy]

After a few more tests, I've decided to go OB all the way.

Since I have enough of the SLS 10s hanging around, I may as well make use of them.

So I'm doing a 3 way stepped baffle with a pair of SLS10s a side in a SLOB/W baffle.



The interesting bit will be the crossover. I can do it all active with MiniDSPs as I have previously, but I'm also going try a 3 way passive crossover with MiniDSP EQ.