[d_c]

There have been a few of these designs done, but I will be doing something a little different with the mounting of drivers and ports. All parts are here or on the way. My drivers ship today from AE. I will be building each as a tall single unit with the SEOS at 33" and using round ports. I'm not a fan of slot ports for some reason, so round it is. The bracing will be tricky with fitting the ports in the front and making a turn up to fit in the box. The plan (for now) is to have curved sides with a maple veneer, and a shaped MDF baffle with a smooth transition to the waveguide using Bondo or whatever is decided to be best. I'm going to build some junky boxes for testing and listening first so I can have the patience to do these right. I am also going to polish the phase plugs to a gloss finish instead of having the brushed look.

These will be used in my media room, which is almost finished. Other gear is Onkyo 818, dual ceiling mounted, clone powered Gjallarhorns, and 6 of the DIYSG ported V-8 for surrounds using front heights. I have an SDX 15 I might use for some nearfield filler, but we'll see if I need it. I'm going to admit now that this room is going to be a nightmare with reflections. I'm lucky this much beef was approved by the authorities as this is the main room of our home. These 3 speakers will be the centerpiece at the front of the room and the only audio gear visible, so I have to make them nice. I call this my Ninja Sound den, because of the wicked-sneaky sound.

Robotbunny and John at AE have been kind enough to field many questions of mine via PM and email, but thought we could move all my questions here so other people can benefit from the knowledge of the guys who have build this design. Hopefully they, and other veterans of this design, will drop by and provide some input

Some questions:

-1 cubic foot for the TD12m?
- tune at 60hz?
- two 4" x 16" ports? Can I use something smaller, like 3"?

I would like to be able to cross these at 60 for music, is that possible?



Below is the progression of the completed build (11/18/2015)

Test Box:


Complete:

Center:

 

[tuxedocivic]

Hey d_c, glad to see you're doing a build log. I will be following along (and stealing your sneaky ninja ideas

).


Unless I'm looking at something wrong, seems to me the M likes 80L and 50hz tune. The lower tuning is a good thing in your case, but why only 1cuft.? Can you get 2.5cuft in your spot? Or does that violate the authorities law?


EDIT 80L? Tux is an idiot.

 

[Jon_B]

I will be watching your build. I have been sitting on my ae td12m drivers for an embarrassing amount of time. I really am set on going with John's DIY td12m minidsp kit. He first dropped a little teaser about back in October. Hopefully we see something soon. Good luck on your build.

 

[d_c]



Quote:
Originally Posted by tuxedocivic  /t/1525663/dougs-td12m-seos12-dna-360-lcr-build#post_24563980



Unless I'm looking at something wrong, seems to me the M likes 80L and 50hz tune...


Can you get 2.5cuft in your spot? Or does that violate the authorities law?

I don't know Tux. I was hoping to understand winisd better by now to be able to figure it out, but I don't trust myself with this kind of dough wrapped up in this build. I would prefer a lower tune in a larger enclosure if it works without bottoming out the driver when I upgrade power to the lcr in the future.


I can use a finished height of 42", "20 deep, but need to keep the baffle width the same to stay in sync with Bwaslo's xo design. I will adjust the curve to match the net volume. I have a false bottom planned if it's a 1 cube to get the height up and to give the ports room. I can rearrange it however to get the larger volume if that would be best.

 

[d_c]



Quote:
Originally Posted by Jon_B  /t/1525663/dougs-td12m-seos12-dna-360-lcr-build#post_24564025


I really am set on going with John's DIY td12m minidsp kit. He first dropped a little teaser about back in October.

He mentioned sharing his MiniDSP settings and design if you choose to go that route, but he is using a different CD with the SEOS.

 

[tuxedocivic]

100hz seems to be the xmax problem area for the 12M no matter what tuning you go with. So as you add power, you're going to have to raise your XO. Doesn't really seem to matter if it's 100 or 25L or 45 or 80hz tuning. 300 watts will push that guy just over xmax. Now, maybe that's acceptable to you. A little over the limit probably isn't such a big deal. In that case I'd go 80L and 50hz tune personally.


What has John and Robotbunny said about it?


EDIT - disregard these statements, I'm an idiot.

 

[d_c]

This was from Robotbunny -

It might be a good idea to re-evaluate such a large volume and low tuning for this particular driver. Some points to consider, since the tuning is less than one octave below the drivers free air resonance there will be a rather nasty dip in the transfer function. The driver will also suffer from over excursion with very little input power (max of 180 watts), reaching ~5.9mm at ~61Hz. Port resonance/port air velocity is an issue as well with one 4" port exceeding ~29m/s @ 2kHz.




Anyway, the larger the enclosure, the less of an air spring the port has at protecting the driver. I wouldn't go any larger than 1.25 with a port tuning of 50Hz. Even then you're right at the upper limit of cone excursion with 300watts if you wanted to upgrade your amplification in the future.


1 ft^3 tuned to 60Hz (two 4" x 16" ports (precision ports come 17") gives the best overall performance. F3 75Hz. 400 watts gives you 120dB at 80Hz...

 

[d_c]

From AE - this was when I was wanting to do an mtm. His comments are regarding 2 cubes per driver.


...If you plan to go passive crossovers, running them off the Onkyo 818, then I would just go with 2x TD12M. This will give you the most efficiency to work with the 135W/channel on that amp. If you go 4 cubic foot for the pair of TD12M, tuned about 45hz, you get some good efficiency. You can get upwards of 120dB. You are only using about 2.5mm of the 6mm Xmax, so you can alway put more power in later without issues to get more output.

 

[d_c]

I should mention also that this room is 14x20', so might not add additional power at all.

 

[tuxedocivic]

I'm an idiot.



I know I know... tell us something we didn't already know

 

[JohnDean]

So you're the one delaying my TD12m's...just kidding.


It's been a while since I modeled it so I may be wrong but I thought I remembered it staying under xmax and looking pretty good with 300w and 1.5-1.75 cubit feet, 58ish hz tune. I wanna say that was using 2- 2.8" ports. I know that's a weird size but I was modeling for port area and not a round ports per se.


Obviously I'm planning a seos12/360/td12m build when my drivers get here and am interested in music/crossing to subs at 60 if it's feasible.

 

[JohnDean]

Tux, just to clarify your suggestion is 80L/50hz which is about 2.75 ft^3, right?

 

[tuxedocivic]

yup


If no plans to upgrade the power, I'd personally go 100L and 45hz

EDIT - Bad idea, don't listen to me.

 

[d_c]

So if using round ports, what would be the length for 45hz tuning? And if I did uprgrade power to 250-300w, I would just need to eq at 100 to limit over excursion?

 

[tuxedocivic]

The length depends on the volume. And the requirement to eq depends on the subwoofer crossover and your willingness to exceed xmax.

 

[d_c]



Quote:
Originally Posted by tuxedocivic  /t/1525663/dougs-td12m-seos12-dna-360-lcr-build#post_24565727


The length depends on the volume. And the requirement to eq depends on the subwoofer crossover and your willingness to exceed xmax.

45hz and 2.75 cubes

 

[tuxedocivic]

AAAHHHHHH F$%K. I had TWO drivers in my unibox model that I saved previously. Ignore all the stupid dip s34t advice I gave you. At least the excursions were right

For the same thing, go 40L tuned to 45hz with these ports.



2 - 3" ports that are 26.3cm long.


2 - 4" ports that are 49.5cm long.


I'd go with the 3" ports I think. They're enough, and a reasonable length. But who know if I can be trusted

 

[JohnDean]

That sounds more like it.

 

[d_c]

Mail me your man card: I'm ripping a corner off

. You could have said they would be great in 5 cubes and I would have believed you!


That makes sense as the size was quite a bit different from my previous plans. Mdf is cheap, so I might try a couple of different forms and compare them with Robotbunny's. I like the side by side listening test along with the measured test. I don't always like the most ideal measurement. I figured that out messing with the hf in the V8 project.


I would like to have some strong content from these in the 60-80 hz since the Gjallarhorns are known to cause issues there.

 

[tuxedocivic]

Haha, ya, I deserve that!


The bigger the cab the more output you'll get in that region. At the expense of some excursion. Building some test cabs is a good idea. I'd normally do that, I'm rolling the dice on my speakers right now