TH-18 Flat to 35hz! (Xoc1's design)

[fenis]

Here's my build using 4ohm B&C SW115's and Djim's cone correction - these subs get crazy loud and clear outside!

Here's a video of some hard kick drum hits outside:
https://youtu.be/A1O2lH6p7kk

Feel free to ask me any questions about building them!

 

[reminence]

Very nice woodwork, much better than mine haha. Did you add another layer to the bottom, whats it purpose (channel cutout on upside down pic with tools)?

 

[fenis]

I actually found a woodwork school in Perth and paid them to cut the pieces for me Yep I added another layer to stiffen the bottom as I read reports of them "walking" during high output.

 

[fenis]

Did some REW measurements yesterday. The -3dB point is about 36hz which is very similar to Danley's TH-118. Note how the upper bass smooths out with 2 subs side by side:

 

[chrapladm]

Looks great. Hard to tell from the response and close proximity buildings but the response looks god for the 15 from what I can tell.

 

[fenis]

Yeah I've got a small courtyard outside but when I have them positioned against the other wall on the right there is a ~4dB boost at 40hz. This position appears to be the same as the hornsresp prediction.

 

[Brian Steele]

Here's my build using 4ohm B&C SW115's and Djim's cone correction - these subs get crazy loud and clear outside!

Nice work! Did you measure your build's impedance curve? It's a great way of determine how close the build is to the corresponding HornResp sim.

 

[fenis]

Nice work! Did you measure your build's impedance curve? It's a great way of determine how close the build is to the corresponding HornResp sim.

Nope - measuring impedance looks a bit complex for me!

 

[Mooly]

Nope - measuring impedance looks a bit complex for me!

If you mean electrical impedance then its pretty easy to do,

http://www.diyaudio.com/forums/multi-way/203497-4-8-ohms-what-does-mean.html#post2841318

 

[Xoc1]

lovely work

God Bless You Stewin this Easter. Thinking of You at this difficult time in Kenya.

 

[ErnieM]

Very nice system. Those KV^2's are pretty sweet as well. Equipped with top of the line 18 Sound components.

Where are you crossing over?

 

[fenis]

Very nice system. Those KV^2's are pretty sweet as well. Equipped with top of the line 18 Sound components.

Where are you crossing over?

Yeah very happy with the KV2's they sound very smooth and natural! Tops are HP at 90hz with 5.8ms delay and subs HP is 28hz and LP 80hz. All 24db/oct butterworth.

 

[Andy1967]

Doing some tests of end-fire array. Next weekend I will do some actual measurements.

Cheers, Andy


Sent from my iPhone using Tapatalk

 

[chrapladm]

Dont know why but those TH18's look huge. They look more square the rectangle. Looks like there 30" wide x 40" h x 28.5". Just the angle I guess

 

[sine143]

i'd say they look more like 25x28.5x42 chrap (as in, the internal panels were 22.5 instead of 21)

 

[chrapladm]

I guess thats all it is. I also though maybe the picture was squashed a bit also. Its just me. sorry.

 

[epa]

Doing some tests of end-fire array. Next weekend I will do some actual measurements.

Cheers, Andy


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hi andy
it looks like the aray is centered around 40hz?
keep in mind that the walls are verry close ,and the walls wil have some influence.
grtz

 

[Andy1967]

I have 1.4 meters between the mouths. (340/60/4) speed of sound/freq/quarter wavelength.
How do you calculate?
Any recommendations to a good overall center frequency?
I know its not an ideal setup, but realistic. Cluster might get you a better performance, but normally I have a stage in between the subs.
Input is very welcome thank you.
I am planning to do measurements next weekend. If you have suggestions to different setups, feel free to share and I will share the results.
/ Andy


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[epa]

I have 1.4 meters between the mouths. (340/60/4) speed of sound/freq/quarter wavelength.
How do you calculate?
Any recommendations to a good overall center frequency?
I know its not an ideal setup, but realistic. Cluster might get you a better performance, but normally I have a stage in between the subs.
Input is very welcome thank you.
I am planning to do measurements next weekend. If you have suggestions to different setups, feel free to share and I will share the results.
/ Andy




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i usualy do 2 meters center>center 6ms delay front sub=~40 hz center freq.
formula

for 60hz its about 4ms delay

 

[$$Maan]

Which version is in the quote below?
It has the ply sitting closer to the cone for cone-correction, making the horn a tiny it longer too, smart.

I've seen several versions in this thread now!
The one quoted below (looks clever but tight)
The one i page 1
Neo dans here:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-179.html#post4037197
And Djim's here:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-197.html#post4281947
Then there's post 1611, 1612, 1633
Which is better=?

When the jam breaks, the bass it will drop.

It's been a whirlwind 3 weeks building these TH18. I did a quick shootout against my old 40 Hz boxes to break in the new ones playing some Metallica before their first use. I was quite pleased with the results. Subjectivey, they seem every bit as sensitive and go a bit deeper than the front loaders they replace even though they model to the same 40 Hz in a quad. I was even more pleased Friday night. Really simple alignment - adjusted the delay to 8.5ms and actually took 3dB off the old setup. Cranked up the B&C's in the THs run STONE COLD, where the old boxes would get blazing hot on top and noticeably lose SPL over the course of 2 hours. Quite a bit more than equivalently-pushed labhorns, in fact.

Fortunately, I have some line arrays to build before I have to decide whether to build more of the same or look into bigger boxes using those same drivers.
They are really nice and easy to move around.

@Andy: where do you store yours?
I'm in Denmark too, would love to have a listen!