2 DR250 build - Europe Materials

[Marflinger]

Only dj, rather experimental subgenres from psytrance and dnb/breakcore...no live band

Only outdoor (freefield, forest usually), target size between 500 and 800 ppl.

I favour to set pa in the front and dj in foh-position (so not between the stacks)
Stacks usually around 16-20 meters apart, toed in.

Idea in my mind was to keep it upscaleable, so be prepared to cater bigger versions by extending the system. Same sound and setting, just bigger pax.


Not much done today @dr250s, just way to cold to be comfy around there.

Found out that i have severe trust issues @hot melt glue, but i think it will be fine.
I screwed little scraps underneath to hold the tubes in position and spread far enough, i hope that doesn't matter in terms of lost chamber volume. But way simpler that way.

I think i'll leave the glueworm around the round edge for stability (and for my trust issues)

All flush to a sandable distance

the scraps to keep it in place and width

cutting it flush and sanding it tomorrow, when the weather is nice enough

Trust issues result in overglueing i guess, but so everything is filled up and a bit messy

Additional, for the german supply hunters: both cabs went through 1m pieve of ht110, the coupler at the end cut flush. I thought it wouldn't be enough, but it sits perfectly as lang as you have no errors. Cut precisly, and 1m is enough for two cabs without any leftover.

[Tom Smit]

This might be an answer for you. I thought that for the T30, the V-plate only 2db (3db for T39 and T48). So, if one would add 2db to the red trace, the difference is very little. These two cabs shown are half the width and half the drivers as per your plan so it should give a fair representation of the differences.

[Seth]

Only dj, rather experimental subgenres from psytrance and dnb/breakcore...no live band....

If you're looking for maximum output outdoor, in the frequencies that can be reasonably be reproduced, Titan is the only way to go. If you build full width (36") 15" loaded T48's you would be WAY ahead of the options you've currently considered. The bottom frequencies the Tuba 60 offers are really only available indoors. Outdoors, to hit the bottom frequency a T60 offers, look at building four times the cab count you're already looking at building.

Outdoors, two stacks of 4 full width (36") T48's will way outperform two stacks of 4 T60's (or 4 double 10 loaded T30's).

Outdoors, eight full width T48's would absolutely rock your world and put you in "god" status compared other options.

Ask around .Read T48 reviews.

Indoors, T60's are magic. T30's still pale in comparison to T48.

All that said, you won't be disappointed with any of the options. The T48 will just be the best tool for the job.

Outdoors, T48 is a different animal.

That said, if I needed or wanted (well... I do want it. But...) the bottom frequency the T60 offers, I would only consider building the 20" wide, single 15" loaded version for it's highly valuable bottom end sensitivity. Absolutely amazing.

There's a lot of "behind the scenes knowledge" this is based on, that I don't have the time to dive into. But, the guys who know will agree.

Keryn, (he) has both. If (he) doesn't agree (please say so), I'm not offended in the least. Take firsthand experience over number crunching.

But... Numbers don't lie. Numbers have no bias.

[Keryn O'Shea]

Only outdoor (freefield, forest usually), target size between 500 and 800 ppl.

If you're looking for maximum output outdoor, in the frequencies that can be reasonably be reproduced, Titan is the only way to go.

Outdoors, eight full width T48's would absolutely rock your world and put you in "god" status compared other options.

100%

[Marflinger]

This might be an answer for you. I thought that for the T30, the V-plate only 2db (3db for T39 and T48). So, if one would add 2db to the red trace, the difference is very little. These two cabs shown are half the width and half the drivers as per your plan so it should give a fair representation of the differences.

The 4db is from the plans, but stated there as the "lower end" (so rather tilt then shift up, but idk where. Relevant only below 80hz)
Even if we assume 2db, adding up together with a flatter response due to stacking (as your chart is single ten an single twelve, it's eight times that per side) it should be pretty close. Below 80hz the t60 rides with a distance of ~5db, assuming the 2db v-plate benefit it would shrink to 3db.

This guessing around was it, what led me to the idea of maybe t30 with a v-plate would be sufficient, as the previously introduced ratio would be somewhat halved (1:2 without plates, 1,5:2 with plate)

Thank you for that comparing chart, makes it visible way better.

Titan is the only way to go

And why should that be the case?

Outdoors, you're loocking at 40Hz+ (actually higher than that, but...)

And again, why should THIS be the case?
Curious, bc i've had 30hz outdoors crunching my stomach and i loved it. I don'r see why the tubas, no matter which, shouldn't do that outdoors.
I'm familiar with room modes and the boundary effects, but way before that the output should be playing below 40 to trigger the room as intended and ideally benefit from the boundarys.

Outdoors, two stacks of 4 full width (36") T48's will way outperform two stacks of 4 T60's (or 4 double 10 loaded T30's)

outperform in terms of? Spl below 80hz? Above? Db per watt input?

But... Numbers don't lie. Numbers have no bias.

Do you have those numbers handy, or can point me to the place where i can find them? Bc the numbers i found walk in other directions...

But this is the point of my questioning, i try to decide on numbers or at least approximations and want to avoid religious beliefs and similar.

Only outdoor (freefield, forest usually), target size between 500 and 800 ppl.

If you're looking for maximum output outdoor, in the frequencies that can be reasonably be reproduced, Titan is the only way to go.

Outdoors, eight full width T48's would absolutely rock your world and put you in "god" status compared other options.

100%

Again, why?

Maybe i will seperate that discussion into its own thread as this is starting to extend, and this is somehow annoying for someone to read this in the future.

[Marflinger]

Two more thoughts on the subwoofer-situation:

Re-read the plans, T30 indeed says 4db increased sensititvity coupling two cabs (similar to add a third cab).
So the true comparison would be 4 T60 vs 6 T30 probably? Or 4 T60 vs 5 T30?

Another thought of mine is the driver, which is always somehow ignored. But there are huge diffferences between the available ones, even between the recommended ones.
As stated before, for instance the recommended LaVoce has around double the Xmax from the Eminence-Variant in the ten inch version.
To keep it simple, i assumed all cabs with the most Xmax available, but i don't know anything about the used drivers in comparisons like "T48 will outperform anything"
Same as the driver, in the comparing thoughts the width the cab is built in also isn't factored in (in terms of keeps variantion range wide open).


Double twelve T48 could be built with a volume of 24 by 30 by 48 inches. Somewhat similar to the Volume of a T60, so the comparison would be 4 T60 vs 4 T48 +3db vs 4 T30 +4db.

And for my other question, if the T30 would improve by adding more Horn:


This is the sketch i promised:

Sure with bracing, but if that would increase the output this would happen at around zero needed storage volume as they can be stored in a flat pack.

And the "big" top/bottom could be clamped on four T30 for transport to have one cart of 2 by 2 T30, secured together by the big plates. This would be exactly one stack, 4 T30s with the top/bottom on the sides and the adittional bracing and 30 inch wide sidewalls somehow seperated.

[Marflinger]

regarding the subwoofer-talking:

viewtopic.php?t=26864 to be continued over there to keep it somehow readable


Back to the DRs; weather just way to cold here to get something done that creates dust and can't be done in the living room. So i went over and removed alll the screws and filled the holes. Package full again, and cab blank now and just holding by the glue. Seems to be fine, nothing moved. Hand full of screws will stay on it, but those were handy little helpers so far (and way smaller than clamping).
For the curious reader, those were 3mm diameter screws, 16mm long. this works fine on all the 12mm material, just sink it in with a bit more torque and the grab is super good enough for keeping stuff in place while the glue sets. Even the thinner material goes without getting ripped through, thank to the screwing head wide enough. Can highly recommend that, esp. when clamps are not available.
Probably nailing fine as well, just dont have a brad nailer (and more trust in the screws)

[Marflinger]

Back to the DR250s (finally)

sadly the weather and then the incoming workload have frozen the progress, not as fast as i hoped to be.

But.
Now i got all the small parts fronm the HF-Module done, and finally glued them in.
Next will be the sides of the HF-Module, and when it is removed from the cab to get the HF-Horn in it i can do parallel on the HF-Horn and the back-cheeks from the LF-Horn.

The middleparts, very tiny indeed, worked best clamped together.

These little pieces annoyed the crap out of me. But it came in handy, to just make one to size, check fit on the cab, take that as a preset, cut it roughly by hand and sand it down until it fits.:

Cutting roughly

Stationary Disksander i found in the shelves did really well on that.

Glue setting like that, yesterday. Today the walls are next, and then sanding of all the interieur.

Found it handy to fix the Diffusor bracket holder on top/bottom as sort of a ruler to fit the parts to. Not sure why the glueing together is later in the plans, figured i will probably notice when progressing further. So far not glued, just the middle one.

While not being able to make sawdust, i found a used rack for super cheap, as well as an amp for the DRs. Now running with a wharfedale 4065 for the biamping; in theory capable of four DRs with the drivers used. (In the HF-section way moren, but so i have it all in one amp)

Nex "dry and clean" steps will be the power supply for the rack, putting the XO-Parts for the DR together and start playing around :)
I look forward to the first sound out of the DRs, i hope the smile this triggers was worth it :)

And i hope i get enough time to finish these boys soon; feels to slow but i just have limited amount of spare time to use for that.

One question came up in my mind: the Horn sheath of the LF-Driver-Chamber, the bigger segment of it (closer to the mouth) is without any bracing. The outer brace will halve the area, but wouldn't it be better (in terms of less resonating) to add 2 braces inside, always in the middle between the middle brace and top/bottom?
Knocking on the outside gives me a quite resonant feedback.

[Marflinger]

And again the glue sets.

But i have to admit, it has a very pleasant and aesthetic view now as the parts come more and more together :)

The sheat from the horn side doesnt close to zero; when sanding the lf-horn flush i wasnt as accurate as i should have been. Will fill that to the right angle, and later the gasket tape will ensure the airtight-situation i think.

Looking forward to the middle braces and the cheeks, as it starts looking like a sound source the will to hear it play gets stronger and stronger :)

[Seth]

Looking good.