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Discussion Starter · #1 · (Edited)
Time to build my new towers.

***EDIT - FINISHED***

FINALLY.

Got my MiniDSP, my 250ft Speaker Cable, 7 new interconnects, my Emotiva 5175 (For Atmos duties)...









































Today I set out to calibrate hopefully once and for all the towers in their current position.

REW 6 point averaging was used, it made the process very easy, and I am pretty happy with the results now. That middle seat (lets face it, the only one I care about in my small room) now has a smooth frequency response.

Here is the pre-calibration averaging for both speakers across 6 positions in the middle seat. Now that the imaging is fixed (roughly 20 degrees toe in) this is actually not a bad average considering the only EQ on these is based on outdoor driver measurements!



Here is the Calibrated Averages, measured in 6 positions again after Eq to the summed averages above. Really good!



The towers have a tweeter roll off at 18khz which I have done myself, I noticed they don't like to really play above there, they naturally want to roll off, so in the X-Over settings for the DSP I simply created a 48db/Octave filter to roll off at 18k. You will clearly see that on one of the tower measurements above, I did the other tower after the measurements. I also added a 25hz roll off also 48db to save the driver from any over excursions since I am going to run these full range in my AVR.


*** Original Post***

I have had the 15" drivers for these for over a year, and just occurred to me the other day that I should build it modular for easy, negates the need for large CNC cutting I was going to do, and I think actually will look pretty cool.

Its been done before, I have seen a sealed and ported version of this, none of them used the 12" mid I am going to use though. For obvious reasons I guess.

Check my sig for my past builds, the thing with this is I am going to be recycling my TPL and 12P80 from my existing towers, I really like the sound I have right now, just wish there was a little more output down low, and this time I would like to cross the mid closer to 1250hz or so to reduce beaming a little, will check out the best area around there with now polar graphs when I get one box built.

The last box had OK bracing, but this being modular, that aim this time was to do the bracing a little better, more LF output, give the mid a LOT more room in a sealed section to breathe, and likewise with the TPL-150. The towers I have although large, really don't leave enough room for all those drivers to do their thing.

SO.

Here is the front face design.



The other build I have seen, which is sealed.



I have already cut one side mostly, and have one mid chamber built and glued, I also had a tweeter chamber built but I am going to redo it shaving off 2cm in height so that will be coming together today.

I am going to have the crossover completely out of the box in its own nice wooden box, I havent decided yet if I will just have that sitting on top or where I will put it, my room is HT centric, so laying them off to the side of one of the boxes will not do. I also just want to keep it all out of the modular boxes, I want those to be as solid and as simple as can be, just some nice terminals on the back of each of them. I will probably make up a thin 100mm high box in the same dimensions as the rest of the modules and use that.

I will build two, though the plan is to build a third down the track when I finally get to use an AT Screen setup to have identical towers.

Here is the bassbox pro model of one of the bass modules:

With the two LF drivers in parallel wired for 8ohms the design should be good for 122db at the -3db point of 45hz.







My current towers in yellow, and new modular towers in red... Approximate.



First port resonance is at about 700hz. I hope to cross over the main woofers at about 200-250hz or so at 24db/Octave. Which brings me to one consideration for the overall design, I know I need to try to cross the main woofers as low as possible due to the CTC spacing rules. The way they are now spaced at 1050mm, exactly one wavelength is 323hz.

Unfortunately the design wont allow a 1/4 wavelength crossover in the mains of 80hz, that's just of no interest to me, I will experiment with this heavily when designing the crossover, I do want these 15's to cover the majority of the impact midbass range, at least up to 150hz if I can. The problem is, given the spacing, I guess I am going to have a cancellation at the 160hz half wavelength yes?

I have some nice jarrah paper backed here, I may use that for the modules in terms of finish, I will cross that bridge when I come to it!

I dont even know how these are going to fit in my room, but stuff it, im going to build them anyway because I am bored! I will make them fit!

Current Room.

Current main towers are 1360Hx360Wx380D









More to come as I go!
 

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Those Beyma 12P80ND-V2 are awesome mids. Glad you kept them in the mix. I'm just going to build modules too. So much easier to build, move around and swap different drivers in and out as desired. I'm putting my TPL150Hs on top as just naked horns since I don't need a solid platform to stack another woofer like you do.
 

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Discussion Starter · #8 ·
What is your room size?
Well the total room size is 2300ft sq.

But I am not using all the room for my theatre,...

Room sim, you can see whats going on here... The whole room is open to the rest of the house too, stairways, 3 of them. So its not sealed at all.

 

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Discussion Starter · #10 ·
As long ad they are at ear level and the mid to tweeter centers are close.
Yeah, well overall the design is going to work better.

The centres will be 1cm further away than they are currently from each other due to these being modules and I have to deal with material widths etc, however with a lower crossover as planned it will be fine, the mid will now be under my TPL, and the base of the TPL throat is exactly going to be ear level, which is still fine for a perfectly on axis response out of that AMT taking into account my seating distance, this also makes the mid and AMT blending relationship end up more in line with ear level vs above my head where it essentially is right now on my towers. Especially on those days when I kind of slouch down into my sofa more...

The CTC mid to TPL will be 300mm, which makes for 1 wavelength at 1133hz.

I think with AMT's though you calculate it to the edge of the ribbon though, which would be 250mm or 1360hz.

All reasons actually why I decided to build new ones.

I am not even going to put a plynth base on these, I was going to, but decided the AMT would end up slightly higher than I would like and then thought I didnt really need it though it would have looked cool.
 

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I'm going to put a thin base under my TPL and use blue tack to stick it to the mid cabinet. Otherwise my cats would surely knock it off lol. Gonna get or build some decent looking speaker grills to protect all the drivers from the same adversaries. :rolleyes:
 

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Discussion Starter · #14 ·
would Dayton PA460-8 18" a good/better substitute for Faital 15" ?
Possibly, not for me though, I want an 8ohm nom speaker. And I have limitations in the width, plus I already have four of the PA460's as subwoofers.

I like the build of the Faitals better than Dayton, the Faital's are rock solid drivers, I would just as soon get an Faital 18FH500 if I were to go 18" mids route. Bigger Xmax, Neo woofers, very rigid frame etc... When using things like the TPL-150 and the mid I am using, cheapest driver I can find is not really the aim here.

http://www.faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=151070100

I almost bought four of those to use as my subs, but the PA460's ended up significantly cheaper at $75 each which for my bass duty, I was happy to take a punt and I have been pretty happy, although I wish they could take a little more power.
 

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Well the total room size is 2300ft sq.

But I am not using all the room for my theatre,...
I think you mean 230 sq feet. Based on your drawing, it looks like your room is about 20 ft wide and 15 ft deep. Also, it looks like you are using about 15 feet of that width, as you mentioned the room opens up.

Your room looks like mine with the sliding door on one side and opened up on the other side. Roughly same dimensions as well.
 

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I think you mean 230 sq feet. Based on your drawing, it looks like your room is about 20 ft wide and 15 ft deep. Also, it looks like you are using about 15 feet of that width, as you mentioned the room opens up.

Your room looks like mine with the sliding door on one side and opened up on the other side. Roughly same dimensions as well.
I think he is including the total room size (including the area that his theater is open to), and not just the room that he uses for his theater. It doesn't make sense to simply calculate the room size if it's open to the whole house.
 
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