2 DR250 build - Europe Materials

[Bill Fitzmaurice]

Now the glue needs some time to set, as its friggin cold here this takes a while...

Urethane needs temperatures of at least 15C plus humidity of at least 50% to cure properly.

[Marflinger]

Now the glue needs some time to set, as its friggin cold here this takes a while...

Urethane needs temperatures of at least 15C plus humidity of at least 50% to cure properly.

Yeah, colder conditions slow down the process a lot. I took them to the heated area for now, to have a regular drying.

As the glue sets, i redrew the wiring, one connector NL4 with a patchbay in the rack to get both amp channels together in that cable.

Regarding the amps, still not sure what to choose.
Highest demand would be 8Ohm/300W per channel for the HF section, 4Ohm/1200W for the woofer. (RMS=program, not peak)

Years ago we just took what flew around or was cheap af. Here the reseller for musicians (thomann) has its own brand, the t-amp-series, where we hooked even subwoofers to.
When feeding into 4 cabs, there will be kind of a high power demand for the woofer. Not sure if i will ever come to the point to power them on full level, i assume this will be pretty loud. I'm guessing to ge slightly below the theoretical rating wouldn't be a problem; there is way more fish in the sea with 1000w/4ohm RMS.
Looking around on aftermarket, the QSC GX-Series seems to be quite common and not totally outdated.
They have another variant, GXD, with a dsp included i don't need. Would they be a way to go for it?

What to look out for? More then willing to get used gear that works vs. cheap new gear that works for now but not tomorrow.
As i don't need any processing/Filters inside the amp, it should be fairly easy to get some old running irons...i thought.
But which series would you recommend?
Which to avoid?

How about staying inside a manufacturer/even series from one? For high/mid/low all inside the same? Any benefit from that?

For context: this will be extended with 8 subwoofers (still to build), so there are more amps to get in there.

Lets say priorities in order would be (from high to low) soundquality, durability/life to expect, pricing. Weight not that much, would be nice to fit inside a 19"-rack.

[Bill Fitzmaurice]

Cold slows curing and it also lessens expansion. One reason why urethane works so well is it expands into the pores of the wood. You want to maximize that. It cures best on a warm humid day.

[Marflinger]

Cold slows curing and it also lessens expansion. One reason why urethane works so well is it expands into the pores of the wood. You want to maximize that. It cures best on a warm humid day.

Yep, to have that conditions outside i would need to move, as humidity is always pretty low where i live.
I'm sure it cures and expands sufficently here inside, i just let it take the time it needs.


I was just stumbling around the subwoofer situation and looked for different drivers.

But first of all, a question to the choice of the cab:
I plan on having 4 per side (the sides far enough away from each other) stacked in 2 by 2 with a v-plate on it.
The Tuba60 doen't have a Coupling in the plans - by the space needed just not used at all? Or resulting hornmouth too small for the 60?

The other part is, that i can build two T30 with the volume of the T60, and stacking the 30s would be way simpler.
I like the idea of having them cubed (30*30*30) either single 12 or double 10. The double 10 would in theory move more air per cab, as the Sd is way higher.

But how would that compare to each other?

Lets say two stacks of 4 Subs, coupled with the V-plate each.
4*T30 loaded with 2*10 each vs 4*T30 loaded with 1*12 each? The 2*10 should blow the 1*12 away?
(The recommended LaVoce 10" have double the Xmax, and are cheaper than the eminence BP102? Available at 113 € right now)

But then:
4*T30 loaded 2*10 and coupled vs 4*T60 loaded 2*12 (whatever blows without getting wider then 30") for instance?

Each variant would probably be a bit overkill; but what would be the audible difference?
The low-end from the T60s still that different when the T30s stacked and plated? Compared to the same amount of cabs from the T60.
Any of the differences besides measureable relevant for playing EDM with a real low end? Anyone compared that, freefield and not inside?

Sure, the T60 will probably still result in higher SPL, bigger driver area and so on. But how wil the stacking and coulping effect that? As i'd need double the space for the T60-Variant, i doubt it will end in double the power in the end?

[Keryn O'Shea]

Regarding the amps, still not sure what to choose.

Do you have access to Powersoft, Admark or CVR 4 channel amps?

[Bill Fitzmaurice]

V coupling works by making the horn path longer, the T60 horn path is long enough without it.

[Marflinger]

...somehow my post between your posts got lost...?

Here again, had it in my browser cache:

V coupling works by making the horn path longer, the T60 horn path is long enough without it.

Thank you for the clarification.

So, the question remains; how would a stack of four coupled T30s including a V-Plate (loaded with dual 10") compare to a straight stack of 4 T60s, loaded with dual 12"? Will there be anything missing? The Volume of the T60 would be double, to store and to carry around. Not sure if thats worth it, thereby the question.

[And another one, out of curiosity: Would the T30 output improve further, when the horn is further extended? On a stack of 2 by 2, the V-Plate and then extending the Front again in line with the single cab front border...)

Do you have access to Powersoft, Admark or CVR 4 channel amps?

I did a brief search, they are somewhat available, but not that many.
The ones i get are of a weird output range; all above my needs for the DRs. Rather for the subs an interesting part; will keep an eye out on them. But the "smallest" went about 2000W/4Ohm; kind of double what i would need.

But from that suggestion, i assume you would go for Class D and digital? Old iron that bad in terms of soundquality?


--------------------------------------------------------------------------------------
Back to the DRs, got a bit further and have the inner section cleaned up, braces on top/&bottom (made from scraps, only one edge important so i took what was in the pile of cutoffs) and the inner horn sides are on it
Screws held surprisingly well, no rip throughs (just one missed target, but thats not the screw's fault)

Ready to glue; so far about half a cartridge used. I assumed it would be more.

screwed in place, ready to set
(Soon I'm going to invest in a powered press for the glue, esp when cold the constant pressing hurts the fingers. The long lines to glue are still to come...)

Nice continuous squishout all around the edges, i think it will be airtight

And again the glue has time to set. Wetted it intentionally this time, will see how that improves the curing.
When set, i can start partying on both ends; adding the back part of the horn and start with the HF-module )

If i manage to keep the few hours daily on that, it'll probably be finished in the first week of the new year )

Another question came up, regarding the ports:
I'm on to doing the versatile option with a coupler. But I'm not sure, from where to measure, and how to place.
Iirc, i think I've seen that variant in one of the build threads here, the wider "Ring" on the outer edgne from the coupler sitting on the horn sheath.
Or should i go for the middle-part of the coupler without that ring and just glue it flush?
And when the Ring is included (and part of the structure in terms of stability); the length is measured from the horn sheath surface, or the outer edge of the coupler?
Any hints on that? Would be very happy to not be that stupid.

[Marflinger]

And pictures from the coupler to visualize my last question:

[Bill Fitzmaurice]

Four T60 will go lower and louder.

[Seth]

Food for thought regarding the double loaded cabs... pretty much the only time a double loaded cab makes any sense is if/when you need to wire the drivers in series to double the cab's impedance in order to run double the amount of cabs per amplifier channel. In nearly every other circumstance, it's advisable to build twice the number of single loaded cabs, as wide as is possible to transport and stow.

That said, this is DIY and you can make them however you like.

A sidenote that taller/longer cabs tend to be easier to load, unload, and wheel around like a hand truck with a pair or built-in wheels installed. The short and fat cabs can still be fitted with wheels, but lifting them (into the bed of a pickup truck/van/SUV or up onto a stage) requires actually lifting them, where a cab that stands tall when transporting can simply be leaned over and slid up with relative ease.

I'm enjoying the build thread. Thanks for all the updates and pics!

[Marflinger]

...as wide as is possible to transport and stow.

The thought went like this: how much can i get out of 30 inch width, to have a compareable situation. T30 is maxed with double 10, t60 with double 12.
Maxed in terms of moving speaker area on that given width.

Also, i need less wood on double cabs, as two sidewalls are left out.
And i'd consider the 30/30-footprint still handy, so i would try to get the most out of that width.
Also a part of the thought is the resulting height when stacked, 60" seem to be fine to act as a stand for the DRs.

...sidenote that taller/longer cabs tend to be easier...

i would couple two t30 together, so for handling the package would be identical. (2*t30 equal 1*t60, 30/30/60)
Volume-wise the question is, if it would be enough to have just 4 of the packages (8 t30 loaded double 10) or if it's worth it to double it (8 t60 loaded double 12).
As i can modify the output of the t30 by coupling/plating them together, im wondering how close the result comes to the t60-variant.
Sure t60 will be lower/louder, but how much?

Somewhere it states, coupling with a plate adds around 4db sensitivity in the low end.

Lets say 4t30 vs 4t60 is around factor of 2 in volume and the resulting spl.
How much does the coupling with a plate add to that on t30-variant?
Rather 1,2 vs 2(t60)? 1,5? 1,8?

Because the plate eats nearly no storage volume, but the t60-variant needs double the volume. Even further extending the horn would be at nearly no volume when stored as a flatpack. Will do a sketch for that thought later.

Edit:
And when feeling the need for more, will there be a limit i can not break by just adding more t30's? A limit i could break when i went for the t60 i mean.

How about combing t30 and t60?
Yes, i've read the part about never combine. But 8 t30 as the speaker stands, in case i want more low end adding 8 t60 as a block an option? Separate signal and processing for them.

[Keryn O'Shea]

So, the question remains; how would a stack of four coupled T30s including a V-Plate (loaded with dual 10") compare to a straight stack of 4 T60s, loaded with dual 12"? Will there be anything missing?

Yes, take a look at the SPL charts provided to see what's missing. We can't ask a T30 to do the job of the T60.

How about combing t30 and t60?
Yes, i've read the part about never combine. But...

No

But from that suggestion, i assume you would go for Class D and digital? Old iron that bad in terms of soundquality?

I suggest that type of amp for the light weight & high power. Old iron still sounds just fine!

[Keryn O'Shea]

A sidenote that taller/longer cabs tend to be easier to load, unload, and wheel around like a hand truck with a pair or built-in wheels installed.

Yes, Absolutely
I noticed this yesterday when loading the T30s after being used to T48s!

[Marflinger]

We can't ask a T30 to do the job of the T60.

Sure, that was not the point.
I asked, how close 4 t30 coupled with v-plate come to 4 t60 stacked just straight, because there are no charts on the plated stack of four.

There is a comparison, when in stacks of 4 or more the longer horn will have an advantage. But the plate makes the path of the t30 longer as well, i just want to figure if that adds up and if so to what.

So lets say, one t30 compared to one t60 equals a 1:2 ratio.
4 t30 and 4 t60 stacked straight should benefit from the same effect each, so still 1:2 ratio.
4 t30 with a longer path by the v-plate vs 4 t60 stacked straight equal to what?
1,2:2? 1,5:2? 1,8:2?
All i could find about that is the mentioned 4db increased sensitivity.

This will probably never reach the t60, which isn't even the goal.
But as stated somewhere, the lower frequency of the t60 is mostly not used, and party ppl aren't used to that frequencies either bc most systems just don't go there. so not sure if there is a need for the t60.
But i don't want to regret it later, as building takes time.

rig of 2 dr250 each side, done with either 4 of t30 or 4 of t60 (1 top for 2 subs) will play the music. When avoidable, i will not go for the t60 due to the storage volume doubled for them.

The graphs don't tell me the answer, i'm looking for somebody who had both scenarios playing and shares the experienced difference between them.
The t30 would be super easy to store, and i could build double the amount of cabs within the same storage space. And by being half the size of the t60, they are better to lift around as well...

[Seth]

...Volume-wise the question is, if it would be enough to have just 4 of the packages (8 t30 loaded double 10) or if it's worth it to double it (8 t60 loaded double 12)...

I apologize if you've already mentioned it in the thread, but tell me a little about your intended use; most likely venue/s, indoors or outdoors, live band and/or DJ, and what genre's