Yet another um18-22 build - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 23 Old 02-01-2020, 06:32 AM - Thread Starter
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Red face Yet another um18-22 build

Important ! Most images will be in a spoiler tag because i don't like scrolling 17 images 5 times when people quote posts.

Hello all who are interested and thanks to everyone who helps giving advice and answers questions.

I'm building a home theater in the living room -> thread.

I'm building 2x sealed Dyaton ultimax 18s.

I'm constricted on box size and placement and this is the reason i will go with sealed.
There's a sketch on that it would look like:

Spoiler!


Room size is 6m (19.6f) by 5m(16.4f), but the whole opened space is 10m (32.8f) by 5m (16.4f). I hope i will get some room gain. I won't be able to the make the box larger than what's on the 3rd picture. Internal volume will be no more than 5.3 cu ft. Will use the rule of 1lb per 0.75 cu.ft stuffing. For the bracing i will make something like mkohman did for his subs. This

Because i will place the front left and right speakers on top of them i will need to think of something like a sheet of acoustic foam and a wooden plate so the spikes of my current speakers will grab, and in the future when i DIY my own speakers.

Because the sealed box will have a heavy roll of, I plan to putting only 200 watts into it and do:
18hz 3db gain q2
20hz 5db gain q2

If i don't get any room gain on the lower frequencies. So this is the worst case scenario.

This is around 8db of gain.
Soo 200watts and 3db gain is 400w
200w to 800w 6db gain
200w to ~1332w 8db gain

Ok maybe a little less gain, but will try to not push more than 1000w. How i'm gonna measure this i have no idea ?

If i get more gain i might need 3-4db of boost and then i will be able to put more watts into the subs.





I don't have money to get everything so my plan is to buy 1 sub, the unik 1 and a mini dsp 2x4 hd next next Monday (10/01/2020). Will build the two boxes simultaneously so it will be cheaper. I have a friend who will calculate the sheets and how to cut them for least amount of waste. Next week (08/01/2020) i will go to the local wood company to order my cut of the material and i will then glue them myself and paint them. Won't have the money for the amps thou so will have to wait will March.

For the amps, they gonna be a behringer because they are quite cheap where i live. I've read a ton about these and other amps, but i will have to use those in the beginning. If they survive for 1-2 years good, will sell then and get something better.

I don't know if i should buy 1x nx6000 or 2x nx3000. The only difference i see is that the 6000 has more small caps. The price difference isn't big but it's going to be easier for me to get the nx3000 in march and after i order the second sub to get the second nx3000.
Because i'm getting the mini DSP i won't need the DSP versions of the amps, so gonna save some buck here.

I won't be able to use both subs in the beginning because i need to re-arrange the whole living room and will need to buy other stuff before that. Read the main build thread for more details =/
Also i'm on a weeding this May and money will be even shorter. So i will try to hook up at least 1 of the subs mid March and the second one will May or June.

Super exited!

Last edited by Quetzalcoalt; 03-03-2020 at 10:18 AM.
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post #2 of 23 Old 02-01-2020, 07:26 AM
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Two 3k's would give you two power supplies and two power cords, and double the fans/heatsinks for cooling, and quad 2-ohm stability (and maybe double the caps if you are lucky with the right amp.)
But also twice the rack space and fan noise. No free lunch.

If you are measuring below 10hz, I'd get the CSL UMIK-1 which is calibrated flat to 5hz instead of 10hz.

I'd say 2 18's in the space would be the minimum, dual 24's and a fp14k would be better, but also significantly more money...
Each 24 has about the same output as ~3 18's, give or take. It's much more compact, much louder/deeper and less distortion.

I don't think it would be wise to limit the mid-bass to 200watts, that's gonna severely limit your SPL.
You are sacrificing all >20hz for more <20hz, you'll have no mid-bass, given you'll be limited to 2 subwoofers and likely a concrete floor, that probably isn't wise.
(But that's sort-of how I started off, gotta start somewhere, so who am I to say no... )

No only will the SPL be low above 20hz, but you'll lose 10db in the first 10ft due to distance-law.
So your dual 18's are gonna sound like dual 6's. (Not really, but you know what I'm saying...)

I wouldn't take the "start cheap and re-do later" approach. In the long-term you are much better off just saving up more money and going directly for better products from the start. Doing otherwise is the approach that is wasting money.

I think you'd be much happier with dual $500 B&C 21's, or dual $200 B&C 18's and solving the upper-bass firstly (20-300hz), and worrying about <20hz later/never.
If space is tight then maybe a single B&C 18/21 and a single SI-24 powered with the FP14k and miniDSP as an alternative.
The only downside I see with that is the unbalanced sound pressure at different frequencies, left side of room vs right side of room from the different woofers. They almost need to be placed behind the seating or under the center channel and close together, so that they sound like 1 extremely loud sub.

I still think it would be better to have a bit of unbalanced sound with authority, then weak 200w upper-bass into already inefficient drivers. The B&C's or PA-460's is like 98db/w/m vs 89db/w/m, that 10db difference is hard to overcome (is never overtaken).

Either that or: just model the box size to allow the full power into both UM-18's, and let the infrasonics be what it is.
Then the >20hz bass (which is the most important bass), will have full SPL at least. 1000w x2 or whatever it does.

As you are probably aware, spreading subs out causes nulls to form at some given frequencies relative to the distance between them, but it provides smoother bass throughout the rest of the room, but can sometimes be localizable; where as placing them together makes it achieve closer to the +6db "ideal" summing and thus a bit louder, but more severe peaks/nulls (depending on placement), and even worse localizability.
Physics and money is always working against us... (never with.)
Everyone has to pick their customizable-poison eventually... (and then they are stuck having to sleep with those decisions forever. The bed is made.)
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Last edited by BassThatHz; 02-01-2020 at 07:42 AM.
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post #3 of 23 Old 02-01-2020, 08:44 AM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post
Two 3k's would give you two power supplies and two power cords, and double the fans/heatsinks for cooling, and quad 2-ohm stability (and maybe double the caps if you are lucky with the right amp.)
But also twice the rack space and fan noise. No free lunch.
Well the nx3000 has a single fan. The nx6000 has 2 fans so in total no matter the configuration i have 2 fans. By looking at the internal the 6000 has twice as big power transformer from the 3000. The only different i see are those caps that are near the fans of the 6000. Yes two amps are twice the space and there will be no rack to place them in. They will be on a DIY table between the subs under the screen.

I know i should talk about pricing but i'm from a different country so i think it doesn't matter that much.
The nx6000 is 374$ as converted from my currency.
The nx3000 is 221$. So i will save 70$ if i buy the more powerful single amp also as you said less space and 1 less power cord.

Quote:
Originally Posted by BassThatHz View Post
If you are measuring below 10hz, I'd get the CSL UMIK-1 which is calibrated flat to 5hz instead of 10hz.

I'd say 2 18's in the space would be the minimum, dual 24's and a fp14k would be better, but also significantly more money...
Each 24 has about the same output as ~3 18's, give or take. It's much more compact, much louder/deeper and less distortion.

I don't think it would be wise to limit the mid-bass to 200watts, that's gonna severely limit your SPL.
You are sacrificing all >20hz for more <20hz, you'll have no mid-bass, given you'll be limited to 2 subwoofers and likely a concrete floor, that probably isn't wise.
(But that's sort-of how I started off, gotta start somewhere, so who am I to say no... )

No only will the SPL be low above 20hz, but you'll lose 10db in the first 10ft due to distance-law.
So your dual 18's are gonna sound like dual 6's. (Not really, but you know what I'm saying...)
Forgot to mention that i'm from Europe so SI subs are not an option. The CSL UMIK-1 might also not be an option because the shipping cost is huge when ordering something from America. Also heavy import tax for products outside of EU.
My dad has a B1500D-PRO active sub that will be placed between one of the daytons on the left side. The small box in the 3d sketch is where his sub will be placed. I have a db meter and i've seen 119-120db at 1 meter from the cone just before the clip light lights up. But that measurement might be from a peek in the room. I can't be sure until i get a measuring mic. I can probably use that as a midbass if i feel lack of it. The b1500d-pro starts rolling of at around 35hz.
About the floor, the floor is concrete with isolation and then wood. So it's a wooden floor ?

I have a video that shows the single pb-1000 doing 106db on my spl meter. But at avg i get 100-102db at most. This is at the listening position. Yes it's corner loaded but still i think those two 18s will do quite a bit.

Quote:
Originally Posted by BassThatHz View Post
I wouldn't take the "start cheap and re-do later" approach. In the long-term you are much better off just saving up more money and going directly for better products from the start. Doing otherwise is the approach that is wasting money.

I think you'd be much happier with dual $500 B&C 21's, or dual $200 B&C 18's and solving the upper-bass firstly (20-300hz), and worrying about <20hz later/never.
If space is tight then maybe a single B&C 18/21 and a single SI-24 powered with the FP14k and miniDSP as an alternative.
The only downside I see with that is the unbalanced sound pressure at different frequencies, left side of room vs right side of room from the different woofers. They almost need to be placed behind the seating or under the center channel and close together, so that they sound like 1 extremely loud sub.

I still think it would be better to have a bit of unbalanced sound with authority, then weak 200w upper-bass into already inefficient drivers. The B&C's or PA-460's is like 98db/w/m vs 89db/w/m, that 10db difference is hard to overcome (is never overtaken).

Either that or: just model the box size to allow the full power into both UM-18's, and let the infrasonics be what it is.
Then the >20hz bass (which is the most important bass), will have full SPL at least. 1000w x2 or whatever it does.
I know lowering the subs to just 200w each will reduce the output by quite a bit. I might run more power to them and EQ until they measure an f3 of 25hz at the listening position and then use the pb-1000 as a shaker behind the couch.
Might see and modal some PA drivers. Have to see what's available here. I know we don't have any B&C drivers but i know we have Faital Pros also a local company called Oberton. But those subs need ported boxes and they might need to be huge (more than 150 liters) and i don't think they will reach 25hz. Most i've modeled before are good for 30-35hz.

As of power i won't be able to drive the subs that hard in the beginning because my speakers are weak. I might be able to get 95-96 db max out of them at the listening position. They are almost 4 meters away from the listening position.

Quote:
Originally Posted by BassThatHz View Post
As you are probably aware, spreading subs out causes nulls to form at some given frequencies relative to the distance between them, but it provides smoother bass throughout the rest of the room, but can sometimes be localizable; where as placing them together makes it achieve closer to the +6db "ideal" summing and thus a bit louder, but more severe peaks/nulls (depending on placement), and even worse localizability.
Physics and money is always working against us... (never with.)
Everyone has to pick their customizable-poison eventually... (and then they are stuck having to sleep with those decisions forever. The bed is made.)
Know about the nulls. I currently have one at around 60-65hz from the single pb-1000 that is corner loaded. I've read quite a bit and watched a lot of videos in the past 2 years.

I just can't wait. I wanted to get those Daytons from the last 3-4 years. I finally have a decent job (for my country at least) and i just can't wait to shake the house.

Uh got confused from all the quoting.

Last edited by Quetzalcoalt; 02-01-2020 at 08:47 AM.
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post #4 of 23 Old 02-04-2020, 11:16 AM - Thread Starter
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Mhm, i saw something while reading other threads. People say to put the limited on the inuke 6000D just 1 click, so it won't go into protect and lower the output. Does this affect the non DSP versions of the amps ? I'm going to get the "newer" (NX6000) model so this issue might no be. I'm only getting the non DSP version just because i'm gonna use a mini DSP 2x4 HD anyway so i save up some money. But if i get the DSP v of the amp and get more stable output just because of that settings i might re-consider.
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post #5 of 23 Old 02-15-2020, 04:35 AM - Thread Starter
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Well, my friend who helped me build the boxes had to leave soon so no pictures of the actual build.
Here is how they look finished.

Spoiler!


The driver is still not here =/ . At least the tracking id says it's located in my city so monday it is.

Now i need to test for leaks, sand it down, and see what options i have for paint.
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post #6 of 23 Old 02-16-2020, 07:17 AM - Thread Starter
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Exclamation Stuffing

I've read a lot about stuffing and i think i will just put as many sheets of polyfill i can fit without compressing it.
The book "Loudspeaker Design Cookbook Seventh Edition Vance Dickason" says that stuffing the box 100% makes the Q lower to as the box size increases by 10-15%
Other posts i found says that the more stuffing you put the lower the SPL will be.

I also found a post that says
"A little stuffing, or at least lining the box, is always a good thing to cut down on internal reflections. Stuffing doesn't really make the box look 'bigger.' What it does is change Qa, the factor for absorption losses in the box. In WinISD Pro, click the Advanced button on the Box tab to change it.

Yellow: no stuffing, Qa = 100
Green: light stuffing, fully fluffed, not filling the whole box, Qa = 20
Red: heavy stuffing, compressed into the box, Qa = 5

Not shown,
Qa = 50 for lining the box
Qa = 10 for fully fluffed filling the whole box"

So there is a Qa of 100



Here is a Qa of 20



And a Qa of 5



So if the box is stuffed to the max i loose 1db of output.
50-ish % non compressed doesn't loose output and lowers the Q and the impedance a bit.

Even thou highly stuffed box will almost make the Q to the 0.707 i think i will lint the sides with 1 piece and put 4-5 lists on the back until it reaches the drivers magnet then compress them just a bit and put something so the stuffing won't cause a lack of airflow from the rear port of the driver.
It should lower the inner resonances too and giving me just a bit lower Q and unnoticeable lost of output.


I can always do the tests but i think i will just do the above said and forget it
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Wow, absolutely awesome, great build!
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post #8 of 23 Old 02-16-2020, 10:40 AM - Thread Starter
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My father was afraid of "kicking" the subs unintentionally so i bought some magnets 12mm by 6mm, drilled some holes on the front baffle from the inside 6cm away from the edges and put the magnets there so they won't be seen. The plan was to buy a metal sheet or something to cover the cone. Ofc before use i will be removing this sheet. I don't like speaker grills, especially metal ones so no matter what i put on front i will be removing it every time i play a movie. Will definitely make some pictures after the boxes are finished to show.

On the feet subject, there isn't anything that i can buy that is a soft rubber. Everything is hard like plastic. Really wanted to isolate the boxes from the floor. I'm considering of cutting some kind of foam, maybe an inch thick and placing the subs on top of it. They won't be moved so there should be no issue.
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Quote:
Originally Posted by Quetzalcoalt View Post
My father was afraid of "kicking" the subs unintentionally so i bought some magnets 12mm by 6mm, drilled some holes on the front baffle from the inside 6cm away from the edges and put the magnets there so they won't be seen. The plan was to buy a metal sheet or something to cover the cone. Ofc before use i will be removing this sheet. I don't like speaker grills, especially metal ones so no matter what i put on front i will be removing it every time i play a movie. Will definitely make some pictures after the boxes are finished to show.
.
I used chicken wire to make a grill for one of my UM18 builds. Turned out ok.
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post #10 of 23 Old 02-17-2020, 08:34 AM - Thread Starter
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Sub number one is here

Holy it's huge; Never seen anything like it. Especially naked. Sadly the amp will come after 10th of march.

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post #11 of 23 Old 02-20-2020, 06:59 AM - Thread Starter
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Well, i've tought a lot about what to do to the boxes in terms for a finish. Painting will require a lot of money because the sides need to be "filled" (the cut exposed parts), then a primer and paint. This would cost me quite a bit and i don't think it will look that good.

There is a 40 min video of a guy on youtube that uses something called "Duratex" that doesn't exist where i live and i can't find anything like it.

So i've decided to try and wrap them in fake leather. There is a place in my town that sells fake leather 1m by 1.4m between 7.50$ and 11$.
I haven't calculated exactly how much i will need but roughly 2 meters by 1.4m should be able to cover the face, top, back and bottom and then 1m by 1.4m to cover the sides. So between 22.5$ and 33$ per box. Glue is around 7-10$.
This is way cheaper and it will actually fit in the living room. Couches are made of leather, furniture has an old style style and i will be adding 12x12cm wooden beams on the ceiling and front wall where the TV is. That wall is actually covered in stone.

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post #12 of 23 Old 03-03-2020, 05:02 AM - Thread Starter
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Yesterday i got the leather and 1kg of glue. They said the glue will work with high absorbing materials like MDF, so i haven't primed the cut part of the MDF.
The initial plan was to cut the sides, blue them and then make a whole wrap around the front, top, back and bottom. I wanted to leave 1 inch of leather to wrap on the sides for a "cool" effect, but the leather stretched a bit and it got pretty uneven. So i crapped that idea and will go with some kind of edged wooden lines or something ( i don't know the name ), see it in the pictures.
I don't have a spray gun so i used a brush to spread the glue on both sides and i think it worked out.
I don't like the color of this fake leather that i choose but the seller was a bit rude ( maybe because of my lack of knowledge ) so i just went with this one and didn't looked into other more "textured" and thicker leathers.
This is the first time i'm doing anything like this so keep that in mind. I think it turned out pretty well.

Images:
Spoiler!


Second box will be done this Saturday.
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post #13 of 23 Old 03-03-2020, 10:16 AM - Thread Starter
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I had plans to go out but the plans changed to i had to stay at home. Decided to cut the hole. After that i pressed the leather against the wall of the flush mount hole and ran the night there. Tested to see if it's going to be hard to put the driver in and out but it turned out quite good. I'v made the flush mount 1-2mm larger than the spec of the driver so this probably helped.
Had to go with a darker leather and with more textures, this looks more plain.

Images:
Spoiler!
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post #14 of 23 Old 03-05-2020, 08:13 AM
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That's a good solution for a finish, and it looks like it's going fairly well so far. I actually considered doing something similar just for the front baffles at some point. I thought a snakeskin or similar textured material would be fun. Keep at it, and keep posting pics of the results!
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post #15 of 23 Old 03-05-2020, 12:04 PM - Thread Starter
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Quote:
Originally Posted by OJ Bartley View Post
That's a good solution for a finish, and it looks like it's going fairly well so far. I actually considered doing something similar just for the front baffles at some point. I thought a snakeskin or similar textured material would be fun. Keep at it, and keep posting pics of the results!
Thanks! Will do. Plan is to do stuffing (when it's actually available =/ because it's out of stock from the past week), put the terminals and feet! I was leaning into putting spikes but the it will be pain to move the damn thing so either some soft rubber feet like the svs one but 10x cheaper or a sheet if isolation foam. I just don't want the thing moving on the floor.
I was going to get a nx6000 but after reading another thread i think i will get the nx4-6000 and use that amp later for atmos channels when i update to XLS2502 in the next 2-3 years.
Problem is that nx4-6000 is not available =/ hope some of the website that offers it will find 1 to send it to me.
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post #16 of 23 Old 03-08-2020, 11:41 AM - Thread Starter
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Well didn't have time to put the leather on the second box but i manage to get the silicon stuffing. It was a 5x2.4 meter sheet and 85% of that went in. I didn't packed it that much. I cut it to fit the in between the bracing and put 2 sheets per "spot". I don't know how to say it. The cable goes though the stuffing to it should not rattle inside the box. Used wood screws to hold the stuffing in place, i was going to wrap around a thick string to hold everything but the i think it won't be needed. I just put one where the back of the motor is so it won't suffocate port.
Box is 98% complete. Need to add those wooden corner thingies to hide the cut leather on the edges and to put some feet. I though the box would be super heavy but it's quite lite for it's size.

Images:
Spoiler!
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post #17 of 23 Old 06-12-2020, 11:20 AM - Thread Starter
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It's not DEAD.
I've finally got the other sub and the NX4-6000. And i just calibrated the system but the graphs are on my laptop that is still hooked up so they will come tomorrow.
For dual 18s i think i get quite low db, but maybe the graphs will help. The subs are not in their final position (images will be uploaded tomorrow) so that might change a little. They are also not in a corner so i loose quite a bit of bass boost.
So i ran the AVRs test tone and calibrated the subs to 78db, just 3db over reference. I ran some demos at -8 because my other speakers just can't do more. I saw that the subs are moving soo much in and out, i reach the -6db from time to time on the nx4-6000. The max bass i got was 110.7db at my listening position.
If i remove the -3db over we get 107db. If we do 115 - 107 = 8db. So the -8 on the avr doesn't lie.

But 110.7db for 2x18. is a bit low for me, maybe the subs have more mm of xmax but damn it looks like they can't do more. I will try to take some slow mo to see how much exactly excursion they are doing.
I did a 20hz test tone at -8 on the avr and -3 in REW (on the 4th channel so i'm getting the +10db LFE) and i reached 110db. This is impressive but yet i think that's the max 2x 18s can do.

I will add the graphs tomorrow, will do some videos as well and the slow mo.

I don't care much below 17-18hz so i put a 48db slope at 13 hz. I'm doing a BOSS (not hover thou) so i will have the TR. Will need help with this one because of my special case.

EDIT:
So i put a Linkwitz-R 48db slop at 13hz on the 2x4HD just to protect the drivers from the 0.01% of movies that have content under 10hz. The winISD looks like this.

This is the driver at 1000w


This is the driver at 1000w with the filter.


This is the free space calculated SPL at 20hz.


I get a ton of room gain. The right sub from 30hz to 10hz is flat. The left one has more spl at 20hz and drops to 10hz but still above the spl from the one on the right. I've made a flat EQ with REW so basically it reduced everything else to match what i was getting at 20hz.
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Last edited by Quetzalcoalt; 06-12-2020 at 11:40 AM.
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post #18 of 23 Old 06-12-2020, 11:46 AM
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Quote:
Originally Posted by Quetzalcoalt View Post
On the feet subject, there isn't anything that i can buy that is a soft rubber. Everything is hard like plastic. Really wanted to isolate the boxes from the floor. I'm considering of cutting some kind of foam, maybe an inch thick and placing the subs on top of it. They won't be moved so there should be no issue.
Here are the soft feet you seek....
https://www.amazon.com/Platinum-Sili..._dp&th=1&psc=1

All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act their dreams with open eyes, to make it possible.
T. E. Lawrence
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post #19 of 23 Old 06-14-2020, 02:55 AM - Thread Starter
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I'm taking the screenshots to post the graphs and i see that i've made a huge mistake. So i will do another calibration =/
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post #20 of 23 Old 06-14-2020, 07:37 AM - Thread Starter
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Ok, here are the graphs.

So here are the left sub only no EQ, right sub only no EQ, both subs overlay to see the difference and both subs at the same time with no EQ.

Spoiler!


Here are both subs with EQ. I tried delaying the second sub with 3, 5, 7, 12, 15 ,20 ms, i always get a massive null somewhere. So 0ms on both subs works great in this position.

Spoiler!


And i added 12ms delay on both to remove a small dip with the center channel. Yes i lose 3db at the 60hz range but i remove one of the dips.

Spoiler!


Here is the room before, after, and the plan to what i'm doing next but updates on that will be posted on my other thread -> HERE


Spoiler!
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Last edited by Quetzalcoalt; 06-14-2020 at 07:53 AM.
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post #21 of 23 Old 06-17-2020, 08:45 AM - Thread Starter
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Quote:
Originally Posted by Falonious View Post
Here are the soft feet you seek....
https://www.amazon.com/Platinum-Sili..._dp&th=1&psc=1
huh i though i answered.

Keep in mind i'm living in eastern europe. I can't use Amazon. I've searched everywhere in my country to find something similar to this but no luck. =/
And shipping cost from other near by countries will be too much to justify buying.
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post #22 of 23 Old 06-20-2020, 06:40 AM - Thread Starter
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I know almost no one is reading this thread but gonna ask here anyway.

I'm trying to think of how can i improve the setup.

I know the midbass problem with the ultimaxes. I have a behringer b1500d that i can hook up too. It's good to around 37hz so i can cross it over at 40hz or 50hz and leave the lower frequencies for the um18s. I've measured the b1500d to around 120db so that would be plenty.

I also have a ground loop issue, i know where it is but i don't know how to solve it right now. So i switch the low pass filter on the NX4-6000, it's a 100hz one and it almost eliminates the hum but now i have two filters, the one on the AVR that is set to 80hz for each speaker and the one in the nx4. Is this a huge problem ?

Maybe i made a mistake going sealed. That 18hz 4th order filter that i put causes a lot of group delay simulated in WinISD, the same i would get in a vented box. I don't benefit from the lower frequencies because i don't really need them. I can maybe hear 18-19hz but the rest it just for shakiness and this shakiness will be handled with a BOSS system.

Maybe next year i could try and make a slot port hole in the already existing 164 litter boxes and try to glue up a port. I will have to think this one because the port might be too bug and the cats might get inside

I had the subs at 78db instead of 75db so that makes a 3db hotter but maybe i'm the first one that would say this, i think it's a bit too much. Even when i turned down to 75db some movies have soo much bass.

I'm looking at the water charts from the above graph files and it's a bit bad. I will have to do more reading to understand the water charts more.



EDIT: maybe a 150-160L box would be enough for a PA 18 or 21 inch that would got to 18-20hz. So instead of destroying the current sealed boxes i might just make new ones. The problems is that i can't keep all subs so the um18s will have to go if go that route.

EDIT: updated the water chart.
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Last edited by Quetzalcoalt; 06-23-2020 at 01:12 PM.
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post #23 of 23 Old 06-28-2020, 06:19 AM - Thread Starter
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Ok i feel soooooo stupid. When i did my initial measurement, i didn't have any filters on the mini DSP and i said i made a mistake that created a 70-80hz null. So i redid those measurements again did new EQ and posted the graphs 2-3 posts above.
I just watched a video with Antony Grimani and i decided to open my graphs again to look at them, and i opened the old one.
When i did the second EQ i didn't remove the the high pass filter that was at 15hz i think. So i'm flat to 8hz not 18hz =/ OMG i'm such an idiot.



I've measured 110db at 20hz, so if i remove the HP linkwiz filter (with is a default of 4th order) i should be able to do 110db at 8hz. I can place a 3hz first order HP filter, just to make those <6hz cone excursion not exceed 22mm.



I need to make "compression" sweeps to see how much i can push the subs. I don't know how to measure the watts i'm pushing to the subs, so i can know the limit on the master volume. I've done tests at -5MV, subs are moving like crazy, but i can't see if the cone is reaching max excursion.
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