S14 - 4 Way OB using Seas and Vifa/Zaph drivers

[bbggg]

Which waveguide are you using, gainphile?

[JonMarsh]

This is the latest iteration of this concept. S19/M for Seas Magnesium.



I am now convinced that 3-way is not optimal. For rigid drivers at least...

You know, I think you're just having altogether too much fun with this! As I've been stalled dead in the water since the end of the Xmas break, I'm especially jealous!! :W

Please keep us up to date on your results as you progress- much appreciated.

Oh, and what do you think is optimal for rigid drivers?

[5th element]

Those SEAS W15CH sure are pretty, with their small and open motor structure I can see why you'd want to use them in an open baffle.

I agree with you that a three way, when using dipole bass, isn't optimal for a dipole loudspeaker. Of course this depends entirely on how you intend to do things, but for hard cone drivers it's difficult to get any design flexibility with the three way I think.

[gainphile]

Which waveguide are you using, gainphile?

They are Monacor WG300. Fits perfectly with XT25 or DX25 plates. But the screw holes are not, hence I use "pressure mount" like Zaph etc.

You know, I think you're just having altogether too much fun with this! As I've been stalled dead in the water since the end of the Xmas break, I'm especially jealous!!

Please keep us up to date on your results as you progress- much appreciated.

Oh, and what do you think is optimal for rigid drivers?

"Fun" is a correct word, but more importantly I'm trying to finish everything by winter which is about... now . Once the cold sets in there is no way I'm doing anything outside !!

At the moment SW, W, and M both covers 2 octaves each, and not pushed to hard beyond their operating range (unlike W22 at 1.5khz!!). I find this good enough, not wanting more cleanliness etc. Of course the tweeters are stil covering 4 octaves so there may be a room for improvement there??

[bbggg]

They are Monacor WG300. Fits perfectly with XT25 or DX25 plates

Nice. Have you considered using the Monacor tweeter? Maybe it is better suited directivity-wise.

[JonMarsh]

Well, I understand the race down to the wire. For me, it feels like there was a trip wire strung across my path and I never got out of the starting gate!

OTOH, I did get the workbench finished and cabinets pulled back out of storage, and actually glued up some trim bits last night... does that count?

Hope you get done what you want before the weather sets in!

[5th element]

Nice. Have you considered using the Monacor tweeter? Maybe it is better suited directivity-wise.

Usually when a wave-guide is used, the wave-guide itself dominates completely on determining what the directivity is like.

I have used the WG300 myself and the XT25 measures pretty much perfectly in it, with the tweeter + wave-guide doing exactly what you'd want it to do, without any 'funnies' showing up in the top octave.

You can see some comparative measurements on this guys website.

http://kotisivu.dnainternet.net/anukaa/index.html

[bbggg]

Usually when a wave-guide is used, the wave-guide itself dominates completely on determining what the directivity is like.

I would imagine that radiating surface diameter would also play a role, as would profile to some extent. The former would probably influence the magnitude of the sensitivity boost, whereas the latter should play a role WRT response smoothness in the 10k-20k octave. Other than that I have no reason to doubt what you are saying.

You can see some comparative measurements on this guys website

Neat measurements, pity there is no dB SPL scaling on the y axis.

[gainphile]

XT25 + WG300 actually have the advantages in this application due to the phase plug. It completely eliminates ~15khz null as you can see in that guy's measurement of Monacor dome tweeter.

This is very similar when I use DX25. Null at 15khz.

Too bad because I recently used DQ25 metal dome and liked very much the resolution. I removed the phase plug on those, though so it displays the null. I wonder if I had the original version with phase plug...

[bbggg]

These driver guys from Denmark and Norway seem to know their stuff, there isn't much that is wrong about what they churn out. On the other hand I'm puzzled they have not looked into waveguides more. They are very cheap to make on an industrial scale, and I'm sure they have the scientific wherewithal to optimize them. As far as I know there is only the SEAS DXT affair, and this looks like a half-hearted effort anyway. As for me, I'm sure I can't hear much above 16 kHz these days, so I'm looking out for you intrepid youths!

[5th element]

The DXT is actually a fine effort, it's only problem is its diameter. It would have been very nice if SEAS has different versions of the DXT, one with an outside diameter matching their 4" drivers, one for their 5" and one for their 6" etc, that way you could match the directivity of the two. The only down side to this is that SEAS like metal cone drivers and usually they would prefer a crossover lower then is ideal for a directivity match.

That said the wave-guides would work well with a good number of non SEAS mid/basses.

I have tried a number of domes on the WG300, well two, the scanspeak 95 and the HDS tweeter. I prefer both of those to the XT25 and I think this is largely because of the bunching up of the off axis response in the top octave. Subjectively I think this adds a little bit of sparkle to the sound which is quite pleasing to the ear. I also compared the wave-guide loaded tweeter to the tweeter without a wave-guide and there's no going back to a standard dome...

[bbggg]

The DXT is actually a fine effort, it's only problem is its diameter

Exactly.

I also compared the wave-guide loaded tweeter to the tweeter without a wave-guide and there's no going back to a standard dome...

I think it's the only free lunch in audio.

[ttan98]

Gainphile,

Would be able to post an image on how you mount your waveguide to the tweeter? An image is better than describing in words.

Thanks.

[gainphile]

Sure .. here's from previous project but I still use it the same.



A plank of wood pressurise the tweeters to the waveguides. And the rear one WG pressurise the tweeter. Obviously care needs to be taken as to not damage the WG !! Makes it very easy to swap tweeters around.

The final version would see 0.5cm wood sticked onto the waveguide, I think...

[AdelaaR]

bi-dipole woofers!? ^^

[Trismos]

Gainphile

Great job. Love the passion!

You first started out in 2010 and since then there has been a few changes to the MiniDSP product line. Have you upgraded anything and are your files available?

You do not show how you mount your subs very clearly anywhere. They are offset much like GRs V2s correct? Would you post a "cabinet" design here or on your blog sometime?

Regards
Dave

[gainphile]

Thanks. Yes, that was a really slow build!

But the benefit: I was able to buy second-hand expensive drivers (seas excel) at half price. It would be unobtainable by me otherwise

I had not "upgraded" the miniDSP, and still use the original 2x4 kits. They're really good enough for me and we had multiple comparison with DCX2496 (original+modified) and even DEQX.

You'd laugh if I show you how the subs are mounted. Basically a plank of wood at an angle

At the moment I'm finishing up the speakers. Just waiting shipment for a pair of Seas DXT. And yes soon I'd post details. There is a certain satisfaction of finishing a project, like my "S15". But that was much easier to design.

[Lazz]

Gainphile, excellent build. I like the simple construction techniques you have used. It makes design stage easy with it still looking very good.

[gainphile]

Some progress on this build.

First due to special price and high aussie dollar I was able to get 4 of these 10" Dayton subs.



They are massive and heavy and I am a bit skeptical putting them on an H-Baffle. The vibrations would be crazy!

So a W-baffle is in progress !



Compared to building H-baffle, the effort is considerably more difficult. There is no way doing it just by using screws, so all needed to be glued.


Also, recently I acquired Seas DXT. I quite like them as they tick all the box:
- Metal cone
- no phase shield
- low distortion
- some directivity

[5th element]

Not that I know exactly how the Jaycars perform, but I think you'll like what the new subs can do.

[gainphile]

Yes I'm keen to hear them asap

But some patience needed... more progress this week.

The W-frame baffle is complete, ... needs paint




Baffle is routed with no mistakes this time :P




It also takes the XT25, another favourite tweeter of mine. Perfect fit except different depth.




I've tested the mahogany wood stain

Raw:




One coat of Tung Oil. Really like it!

[5th element]

Those look great! :T

That was always one thing I really liked about open baffles, if you want to make a driver change it's relatively easy to fashion a new baffle without it being a problem, unlike a normal veneered and finished box.

[JonP]

4 RS265-8s? Wow, that'll have some capabilities.... :T

Nice to be able to swap those two great tweeters for comparison.. good to see someone using the DXT... And, about the XT25 fit, nothing that making a thin foam gasket to shim it up wont fix...

And that Mahogany!! Wow, nice looking stuff!! A great look with the Seas cones and copper plugs, will look even better after the finish...

Awesome project... keep it coming! There's some of us overworked and underproducing guys out here that need our vicarious fixes... :W

[gainphile]

After 3 coats of Tung oil....

Perhaps another one or two to follow

[gainphile]

Side 1 finished.. but running out of time



It's very heavy 8O :T

Will be a fun weekend :P

[Jonasz]

Sweet!

That's what the Orion should have looked like from the start, Beethoven class on that design, congrats! :T

[5th element]

Wow, that looks very nice indeed and having the za14 next to them really lets you appreciate the more compact form. Lava lamps for the win though

[Evil Twin]

Side 1 finished.. but running out of time



It's very heavy 8O :T

Will be a fun weekend :P

Impressive craftsmanship- we will look forward to the results of your weekend...

[gainphile]

Some more pics while I'm taking a break




The sub section:



To grill or not to grill is the question ... I'm thinking of retro "advent colour" grill.

[charlesd]

Wow, those are some impressive looking speakers! I made a dipole with single sealed RSS265HF-8 10" Subwoofer and and 7" Dayton RS-180 and it weighs about 40 lbs. I put adhesive felt pads on the bottom and slide them out into listening position (I have cork flooring).

I think the Advent grill would look great with the mahogany. I'm looking forward to hearing your listening impressions and how they compare with the S20Z. Have a great weekend!

[gainphile]

Great build there Charles !! Definitely better and smoother finished than mine

I've completed the speakers now.




Mostly pleased with the W-frame woofers. They really work, I can see the woofers pumping violently on some materials but the cabinets do not vibrate !! Magic.


Very clean even crossed at 120hz.






As usual waiting for a really nice warm day for outdoor measurements and xo fine tuning. But otherwise Spring is here and I'm looking forward for dust-free summer and plenty of motorbike !!

[charlesd]

The burst decay is looking really good. Also, thanks for writing the "5-Steps OB design" article. I helped me dial in the EQ from my OB speaker better since previously I had only been using indoor measurements and it wasn't as accurate and I noticed a marked improvement in the midrange sound.

[gvr]

Thanks for sharing! I'm curious about the acoustic effects of building a more compact W-frame; how did you decide on the dimensions for yours? Do you know how short you could make it without it starting to radiate like a ripole?

Cheers!

[EdL]

Very Fine Work...I would benefit from the dimensions for the W-frame as well. :W

[gainphile]

Well it seems that these are my last loudspeakers after all. Have not built anything since! Except for the 'R16' which was for a research client.

A video on how it sounds... somewhat

http://youtu.be/OPtOr09K4ro

edit: I'll post the dimensions tomorrow! Sorry for the much late replies!

[Jonasz]

Nice speakers!

Why did you change to the XT25 tweeter?

[5th element]

Nice speakers!

Why did you change to the XT25 tweeter?

That's exactly what I was thinking.

[gainphile]

The highly-technical reason was because I only have a pair of DXT :P. I keep moving from single to dual back to back tweeters, in this case I have 2 pairs of XT25.

I can say, though I really like the sublime smoothness of XT25 on the higher frequencies. But DXT is very clean around 1.5khz.

Here's another video of the XT25 on acoustic guitar:

https://www.youtube.com/watch?v=RhB0189atqE

[5th element]

Ah you have them back to back, that makes a lot more sense! I do love the way the XT25 sounds though so I can see why you're using it.

[tktran]

The R16 on your website sounds interesting. Can you share any more details about the commission process, or goals of the project?

[davewantsmoore]

The R16 on your website sounds interesting. Can you share any more details about the commission process, or goals of the project?

Snap. I was going to ask the same q. It has a big-ish step in the coverage pattern (1->2khz) ... but depending on what the 'research' is I guess that might not matter

[gainphile]

Very Fine Work...I would benefit from the dimensions for the W-frame as well. :W

Ok, so I went to the cold outside to get measuring tape

W x H x D = 31cm x 59cm x 31cm. The width of the slot is 19cm.

It's one of those builds which I cut as I go, to fit the subwoofers. Not sure what 'ripole' is in the previous thread but they are definitely dipoles. Like those of Linkwitz Phoenix, only smaller and vertical.

[gainphile]

Ah you have them back to back, that makes a lot more sense! I do love the way the XT25 sounds though so I can see why you're using it.

Yes, they 'conveniently' beam too which is appropriate for the dipole application. Although not as smooth directivity-wise as compared to the DXT.

[gainphile]

Snap. I was going to ask the same q. It has a big-ish step in the coverage pattern (1->2khz) ... but depending on what the 'research' is I guess that might not matter

The goal was not very glorious... someone asked me to build the earlier 'S16' prototype. I thought they were crude and ugly hence the refined 'R16'.

The acoustic requirements was smooth & constant directivity. Hence transition from dipole to omni being near-perfect, with a caveat: forward directional only.

Like this:



I have a video :W

The cabinet changes caused deviations from the prototype but I think it's 'good enough'

Now, I have a mixed feeling about rear firing tweeter. For education perhaps I could build one with DXT as rear-firing and keeping the horn+D220Ti as forward.

[Jonasz]

Yes, they 'conveniently' beam too which is appropriate for the dipole application. Although not as smooth directivity-wise as compared to the DXT.

Probably sounds better too? Haven't heard the DXT but the similar H1212 have a very annoying sound to me that I can't put the finger on. The RS28 wich I compared it to have a very relaxed sound comparatively, as do the XT25.