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-   -   FoLLgoTT's build: 18 x Peerless XXLS12 (http://www.avsforum.com/forum/155-diy-speakers-subs/1507428-follgott-s-build-18-x-peerless-xxls12.html)

FoLLgoTT 12-24-2013 06:04 AM

My new bass array is done! cool.gif

It consists of 18 x Peerless XXLS12 each in about 65 l. A Sanway FP14000 provide the necessary electrical power to the drivers. Since the XXLS12 are not as power hungry as some of the bigger 18" one amplifier is enough to reach reference SPL at the very low end.



The room is made of stone and concrete. There is 60 cm rockwool at the back wall to absorb the length mode. The rest is killed by an equalizer (K+H Pro C 28). The signal chain is pretty flat to 3 Hz. So it was no problem to reach -3 dB @ 3,3 Hz. I already measured 115 dB at 4 Hz. So reference SPL is no problem here.






The three front speakers are self-made. I built them a few years ago. Back then the design goal already was in-wall usage and the target frequency range 100 - 20,000 Hz. The waveguides were designed to reach a near constant directivity. Finally these speakers got their suitable subwoofer system! smile.gif

The rest of the room is not finished yet. So the measurements will change a bit when more absorbers and diffusers are placed on the walls.

FoLLgoTT 12-24-2013 06:04 AM

This is the design planned with a CAD software. The curved screen shall be in front of the baffle wall. Later everything will be covered and only a big picture will be left for the viewer.




Then I started the building. I used MDF for the enclosures. First step was the milling and sawing of the cutouts for the 18 drivers.





Then 144 holes had to be drilled and 144 drive-in nuts had to be inserted. eek.gif




I needed 2 l of wood glue for the 4 enclosures. cool.gif




The cables were fastened with hot-glue to avoid rattling.



The edges were milled to avoid MDF's destruction when the heavy enclosures got moved through the room.





Each box is damped with Iso Bond. I used Iso Bond, because I had much left from my experiments with metal pane absorbers (VPR).



The 4 mm² cables are soldered to the driver's terminals. There are 3 in parallel and 3 of those in series. First parallel, because this averages variations of impedance.








Since it is a cellar room, mold is always a problem. So I left air behind the front speakers. The baffle wall should be sealed though.



FoLLgoTT 12-24-2013 06:04 AM

*reserved*

FOH 12-24-2013 06:15 AM

Wow, stunning!

XXLS12 superb stuff, well executed!

Textbook reference build here, is the rear wall damping spaced? Curious about the mid dome mfr,? What's your listening distance measurement, and what percentage that is of total length, from front wall.

Outstanding, this will be one for the ages

filtor1 12-24-2013 06:28 AM

eek.gif WOW! That is epic.

jpmst3 12-24-2013 07:53 AM

Amazing!cool.gif

More pix!!!

NWCgrad 12-24-2013 07:55 AM

Nice build...cool looking LCR design. What are the drivers? Active or passive crossover?

I bet it sounds awesome.

Adhoc1 12-24-2013 10:37 AM

Very impressive FoLLgoTT! (But I am not surpised, judging from your previous posts) Will you hang up a cloud to cure the ceiling reflection or redirect it to the backwall?

FoLLgoTT 12-24-2013 01:22 PM

@all
Thank you! smile.gif
Quote:
Originally Posted by FOH View Post

Textbook reference build here, is the rear wall damping spaced?

It will be spaced by about 10 cm. The reason is only to avoid mold in this cellar room.
Quote:
Curious about the mid dome mfr,?

The mid dome a Tang Band 75-1558SE. The full documentation of my speakers is here. Sadly only in german right now. But maybe there is a online translator for PDF's out there?
Quote:
What's your listening distance measurement, and what percentage that is of total length, from front wall.

The microphone's position was 4 m distant to the front wall. Room is 6 x 4,8 x 2,2 m. So measurement was taken at 2/3 of room length.

Scott Simonian 12-24-2013 09:18 PM

Hot damn! eek.gif

DS-21 12-24-2013 11:31 PM

What a well-executed room! Though the advertised subwoofers are not nearly as impressive as those mains.

Don't get me wrong, it's an impressive subwoofer setup, but those mains look fantastic. I love the mid/tweeter WG module. Overall everything is just as impressive as it gets in design and execution! When someone not only gets the big stuff - axial FR, polars, adequate dynamics, etc. - right but also thinks through things like "Sie unterscheiden sich nur durch die Position des speakON-Anschlusses an der Unterseite." - "One can distinguish the three speakers from one another by the placement of the SpeakOn connector on the underside [of the cabinet]" I'm impressed.

What program did you use to make the polar map on pg. 15?

FoLLgoTT 12-25-2013 01:32 AM

Quote:
Originally Posted by DS-21 View Post

Don't get me wrong, it's an impressive subwoofer setup, but those mains look fantastic. I love the mid/tweeter WG module.

Thanks! smile.gif

But the dual waveguide was not developed by myself. A friend of mine did it. He simulated it with ABEC and built several prototypes. He was so friendly to let me build my own speakers using his design. The rest is my own development, of course. smile.gif
Quote:
What program did you use to make the polar map on pg. 15?

It was done in Excel. I exported several frequency responses from ARTA and made my own diagram. ARTA's directivity patterns are a bit ugly. Excel has more possibilities to make it look good. wink.gif

shadyJ 12-25-2013 06:04 AM

What a terrific room. The speakers look like those Genelec 1000 series, is that their pedigree? If so, amazing, I have been salivating over those 1000s for awhile now. Real nice subs too, the XXLS are beautifully linear. I bet that whole system hardly needs any EQing at all, if any, which, to me, would be the ideal. A true reference system. Beautiful!

gpmbc 12-25-2013 06:39 AM

Grrrreat!

eXa 12-25-2013 07:55 AM

Omg, that wall is a beauty!

bossobass 12-25-2013 09:25 AM

F,

Too cool.

I'll be interested to get your feedback on replay of the heavyweight soundtracks at reference level with 22L in 2200 cubes. smile.gif

What the he!! does "Constant Directivity" mean? confused.gif

Have you heard the TB mids yet, and, if so, how do you like them, subjectively, and do they handle reference playback in your space?

Thanks for consistently great info...

FoLLgoTT 12-25-2013 10:05 AM

Quote:
Originally Posted by shadyJ View Post

What a terrific room. The speakers look like those Genelec 1000 series, is that their pedigree?

In fact the model was the Neumann O 410. But Genelec has very similar models, that's right. smile.gif



Quote:
Originally Posted by bossobass 
I'll be interested to get your feedback on replay of the heavyweight soundtracks at reference level with 22L in 2200 cubes.

At the moment the reverberation is just too high to enjoy reference SPL (about 500 ms). When the room is furnished and more absorbers are placed I'll catch it up. smile.gif
Quote:
What the he!! does "Constant Directivity" mean?

It means that beam width is nearly constant at all frequencies. Every driver begins to beam at frequencies larger than its diameter. Because of this phenomenon typical 2- or 3-way systems without waveguides have jump discontinuities in their directivity patterns. They occur at the crossover frequencies. For example the woofer already beams at 2 kHz, but the tweeter acts like a sphere at this frequency. So the speaker beams much up to 2 kHz and when the tweeter comes into play it abruptly radiates in all directions. This leads to a colored diffuse sound field. Waveguides can greatly help to linearize the overall directivity.

I must admit that my speakers are not constant in this regard. But rather linear with a slight beaming toward higher frequencies. wink.gif
Quote:
Have you heard the TB mids yet, and, if so, how do you like them, subjectively, and do they handle reference playback in your space?

Yes, I listen to my speakers a few years now and I really like the Tang Bands. They have low THD and very low K3. Even at higher SPL I never experienced any harshness. The sound is very clean and direct (because of the waveguide).

ChopShop1 12-25-2013 12:52 PM

Absolutely stunning FoLL!! That is truly an inspiration. The 60cm on the back wall seeming to do the job? What is your tie angle for those mains? They look integrating for sure

noah katz 12-25-2013 01:10 PM

Extremely impressive, Nils!

The only thing I wonder about is the fairly sharp edge transitions on the WG's.

Are the CNC'd baffles available for purchase?

If not, is your friend willing to make the path programming available?

This would be a fantastic addition to Erich's range of kits.

FoLLgoTT 12-26-2013 01:01 AM

Quote:
Originally Posted by ChopShop1 View Post

The 60cm on the back wall seeming to do the job? What is your tie angle for those mains?

The absorber is not finished yet. But there is still something of the first-order length left that has to be equalized.

The mains are pointing toward my listening position which will be at about 4 m from the front wall. This is about 2/3 of room length.
Quote:
Originally Posted by noah katz View Post

Are the CNC'd baffles available for purchase?

If not, is your friend willing to make the path programming available?

Sadly not. He is working at Sennheiser now and he won't publish his waveguides nor sell it.

imagic 12-26-2013 01:50 AM

The end result is a thing of beauty.

coctostan 12-26-2013 11:36 AM

I concur with these guys. Very well done. The mains are so well done I thought they were actual Genelec's at first.

SXRDork 12-27-2013 11:23 AM

Wow! This is just awesome! I'd love to see more pictures of the finished build.

What material are you using to fill gaps between the LCR speakers and the wall?

FoLLgoTT 12-27-2013 01:53 PM

Quote:
Originally Posted by SXRDork View Post

What material are you using to fill gaps between the LCR speakers and the wall?

I used rubber mats used to damp the rumbling of washing mashines and some round PE foam material used for windows (like this). I hope that helps.

RASUBS 12-27-2013 03:10 PM

Great system, nicely build to.

Which Peerless xxls12 woofer did you use ? The 830845 ?

SXRDork 12-27-2013 03:32 PM

Quote:
Originally Posted by FoLLgoTT View Post

I used rubber mats used to damp the rumbling of washing mashines and some round PE foam material used for windows (like this). I hope that helps.

Thanks, I need to do something similar around my speakers.

morca 12-27-2013 05:20 PM

Wauw!! This is a awesome build,flat to 4 hz .......very nice job smile.gif

FoLLgoTT 12-28-2013 01:14 AM

Quote:
Originally Posted by RASUBS View Post

Which Peerless xxls12 woofer did you use ? The 830845 ?

Yes, it is the P830845. It has a dark paper cone. The motor is the same for all models, only the cone, stiffness and impedance vary. The Klippel measurements are pretty linear with low DC offset.


@all
I finished the housing of the 55 cm thick porous absorber on the back wall. I left about 10 cm distance to the walls to avoid mold. These are outer walls and the house is not damped. So it would be a problem to put rockwool directly on the wall. I will install vents which circulate the air behind the absorber. The absorber's front will be covered later when I install rear speakers, diffusers etc.





The measurement is pretty good now. The final absorber leads to better restults than in my experiments. smile.gif





There are no modes with long decay left. I'm very happy with these results! smile.gif

I calibrated the system to reference SPL and listened a bit to various scenes and trailers. The subs were calibrated +5 dB hot.

Wow! Movies like "How to tame a dragon" or "WOTW" with full single digit frequencies are no problem for my system. I don't really hear those single digit frequencies, but I see the door moving in synchronization with the cones. biggrin.gif I hope the couch will vibrate at these frequencies when the room is finished.
Then I played the THX trailer "Amazing life". Usually the mushrooms easily bottomed my old system at high SPL's. Now they are played without a problem. It is just fantastic how the pressure wave is thrown in your face! My wife came down and was shocked that the whole ceiling (concrete) was vibrating! cool.gif

maxmercy 12-28-2013 03:59 AM

Wow. Just wow. Very 'octagon-like'.

Be honest. Do the Amazing Life trailer mushroom blasts sound clean to you? I always thought they were distorted, but chalked it up to my system. Sure enough, it was terribly clipped when I analyzed the waveforms, esp the lossless version.

JSS

FoLLgoTT 12-28-2013 05:57 AM

Quote:
Originally Posted by maxmercy View Post

Be honest. Do the Amazing Life trailer mushroom blasts sound clean to you? I always thought they were distorted, but chalked it up to my system. Sure enough, it was terribly clipped when I analyzed the waveforms, esp the lossless version.

No, in fact I hear the clipping, too. I always wondered why this trailer sounds a bit strange, while the other movie scenes don't. Good to know that the source stream is clipping and not the bass system. Thanks for the info! smile.gif


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