62 cf Ported in an 11,000 cf room? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 57 Old 08-15-2017, 09:04 PM - Thread Starter
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Dual 50+cf Sonosubs in an 11,000 cf room

My large 11,000 cf room is on a suspended floor, and has an alcove about 8' away from the MLP that seems to provide great boundary gain. Despite the room size, my single VTF-15H MK2 gets me flat response down to 14 Hz and the suspended floor really energizes for some good TF. I'm ready to take the plunge into DIY and am looking at building a massive ported box to fill the alcove. The alcove could accept a box as big as 68" wide, 31" deep, and 51" high without blocking the window or being noticeable. It would seem that a box as large as 62 cf could get me some serious extension with multiple 18" drivers and the suspended floor will make for a fantastic experience. I am new to the DIY game and could really use some help deciding on the best approach.

Is that enclosure size too big? Should I aim for a 10 Hz tune or is that too low? What drivers would you guys recommend?
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post #2 of 57 Old 08-15-2017, 10:54 PM
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That sounds like a great project...........A member on here just did a huge box like that with a couple a XXX re audio drivers in it.


I will try and remember who and link you to their thread.



Sounds like a solid plan to me.........



You also need to decide if you want SPL or to go as low as possible etc etc.



Lay out your goals and intended usage to get the best answers possible.

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post #3 of 57 Old 08-15-2017, 11:50 PM
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That's too big for a single box. I'd suggest building 3 or 4. Tune to around 14-16hz. Put a single 18 in each box. My boxes are about 38 cubes total, and they're too hard to move around. I'd say go with either the HST18, UM18-22, or 21ds115-4. If you have good room gain, the 21ds will probably get you more overall output.
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post #4 of 57 Old 08-15-2017, 11:58 PM
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Impressive thinkingly of the largish ! . . that ONE room is "larger" than my entire household,

and 14 hz with only 1 sub - why, that sounds almost too good to be ---nevermind.

(Now I feel bad for building "only" a 40 ft^3 box . . )

for as low on the learning curve of modeling and almost everything else related to the learned and applied science of acoustics as I am . . . .

I'd love to see the REW ( or whatever) sweep chart for that, that should show some spectacularly awesome science / acoustical physics /optimized sub placement at work . . . . Did you do that yourself?

and , student that I may be , I've been at the AVS rodeo long enough to know to legitimately ask : What makes that alcove the "best" place for sub placement wrt uniform bass response throughout the room or at least at the most important seating?

I know! I know! : It won't block the window. Everybody knows that any optimal sub placement wouldn't dare block a window. The HT Police -there is a heartbeat

Sounds like greatest DIY project / sub challenge ever.

I can't wait for the answer from the resident guru's tripping over themselves to be first to crack this nut.

Are you from Texas? Over 6 months ago a guy wanted to get 3 boxes built for the DIYSG 1899 speakers.
Ironically, his handle is , iirc, Lumens Lover, (a lover of light?) and yet all he's really done in the past 6 months is keep us in the dark . .

the advice from post #2 , spot on

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post #5 of 57 Old 08-16-2017, 07:12 AM
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I agree with @notnyt I would not build a single enclosure that large. Not sure exactly if it is an odd shape that space you have to fit it into or will it basically be square or rectangle? But anyway I would break it down into a few smaller enclosures.

For drivers that depends on your budget UM18", SI 18" or 24", Mach 5 18", 21", 24" or maybe even the 32" if you want to really go crazy.

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post #6 of 57 Old 08-16-2017, 08:37 AM - Thread Starter
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Great replies already, thank you all.

I can't find the thread now, but I saw that someone had built a huge 8' high 50+cf enclosure and had a photo of his small child inside the port, and that's what led me to believe that a huge enclosure might be perfect for my situation, especially since I have that alcove that is currently unused and happens to be the ideal location for a sub as far as boundary gain, based on my previous testing.

I see multiple people saying that's too big for a single box. Could someone please explain how to determine what the maximum size should be?

My thought was to tune the box as low as 10 Hz since the suspended floor really gets moving and creates an amazing experience. I know in some rooms with concrete floors, 10 Hz output is near useless, but I'm thinking in this room it will be great. Unfortunately I can't get that low currently to know if that is the case.

As far as output vs. extension, am I wrong in thinking that I don't need output above 115 dB, and at that point I'm better off going for more extension? In other words, ideally I'd be flat down to 10 Hz with 115 dB of headroom, and anything else is just extra that I won't use, assuming I am only watching movies at reference?

I will do some REW sweeps tonight and post them. I know that I can't overcome physics, but one thing I will say about this room and particularly this alcove in the room, is that when I first got into this game, I bought a lowly Cadence CSX-12 Mark II and put it in that spot, and actually got impressive TR, I assume due to the suspended floor, to the point that when I demoed the Interstellar intro scene for my boss' wife the TR literally brought tears to her eyes. Things are massively better with my current VTF-15H MK2, and I can only imagine what it will be like with a real monster over there. The only explanation I have for the "too good to be true" output in that alcove is that it has so many boundaries close together, creating a situation where the sub is essentially in two corners at once. There may be some other boundaries at play here as well, as while the entire space has a full height cathedral ceiling, the very front of the house (where the alcove is) has a separate cathedral ceiling at 90 degrees from the other.

This project is the first of many, and I'm really trying to build this as a starting point for the room, with the intention of building some smaller boxes for the other parts of the room to smooth the response and fill in gaps due to the room response.

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post #7 of 57 Old 08-16-2017, 09:12 AM
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Quote:
Originally Posted by aron7awol View Post
I see multiple people saying that's too big for a single box. Could someone please explain how to determine what the maximum size should be?
Really what they are saying above is that you won't be able to move that 500lb monster once you build it.

My vote goes to the 32" sub. Build it!
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post #8 of 57 Old 08-16-2017, 09:40 AM
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To quote Bill Fitzmaurice (sp?): (correct me if I'm wrong, please)

If you have more money than room, build sealed. If you have more room than money, build horns.

The "tallest" horn in memory yet green was the HZhorn but it was not 50 ft^3. google it. and it would probably weigh close to 400#

One of the most recent OMG ROI builds is the SUBMAXIMUS V3 using the PE UM 18-22. talk to @hd0823 .

My Max V3 using the UXL weighs close to 350#.

you might get 6 or 7 drivers for the cost of 1 of those 32"'ers . . .

but a half dozen of those 32"ers sealed would be a very sexy one of a kind line up . . . it's only money

and looking ahead wrt the full spectrum of HT - what about room treatments?

the RT60 and the ETC and all that stuff AND how and what was done in showing professional measurements wrt the "before' and "after" would probably make for a PHD dissertation . .

Please, Sir. Do go on . . .

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post #9 of 57 Old 08-16-2017, 10:42 AM
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given your setup, i assume bang for the buck is important here?


~21 cubic feet (net internal volume) with 4x 2.5"x48" long ports will tune it to around 12hz or so. plugging one port will drop tuning to around 10hz. cabs would be about 30" x 30" x 48" to allow a little wiggle room and to allow a little spacing for wiring on the back. keeping the cabs to 48" tall should help with cutsheet optimization. at ~30" width for all the main panels, they will fit 3 per sheet with little waste that can be used for bracing, so overall, i don't think a ton of material goes in the dumpster with this one.


brace them up bigtime. :-)







the um18 would be a good choice for this application, powered along with an inuke6000dsp amp.
with 1100 watts or so to each driver, this is roughly 2pi space response (outdoor model, no room gain).
with room gain, you'll probably be flat or possibly rising somewhat to 10hz.
one sub probably overkills your mains, but 2 subs...just because. :-)





the big problem (to the extent that there is any) with notnyt's build is it required lifting the second cab on top of the first (and his drivers are beastly on top of that, 2 per cab).


with these, even though they would be heavy, they would be manageable. carpet sliders could ease sliding them in and out of place.


this is just a first pass concept. calculations would have to be refined if proceeding.
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post #10 of 57 Old 08-16-2017, 10:44 AM
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I would recommend that you download the FREE WinBox v.4.08 Excel Spread Sheet as well as the subsequent ubase628 Speaker Data Base File [although NONE of the three ubase files contain ANYTHING larger than 15-in]. Unzip into SAME Directory, start WINBOX and IMPORT the ubase628 file. You COULD also IMPORT the ubase19 file....but I do NOT recommend that you IMPORT the ubase410 file, since you would have to respond to hundreds of DUPLICATE menu boxes [NO, I don't KNOW if ubase410 is a subset of ubase628....but I suspect that it MIGHT be].

For other candidate Speakers, you would have to enter DRIVE UNIT PARAMETERS obtained from either the mfr's website or by searching for candidate Speaker Parameters.

WinBox will AUTOMATICALLY tell you whether a particular Speaker is best suited for CLOSED, VENTED [or BOTH???] types of Enclosures. In the CLOSED BOX Menu, a STANDARD Design will be displayed. To investigate Alternatives, enter User Data in the BLUE Entry Fields, info re. Damping Material and Leakage, as well as desired Qtc=0.707 [default, which will provide Critically Damped Transient Response, i.e. minimal Hang-time; or Reverberation]. Then Click on "Optimize Vb for wanted Qt", so Spread Sheet will calculate the OPTIMUM Box Size that provides Qtc=0.707. Be sure to click on UPDATE; for Graphs and Frequency Response. Additional Performance Charts are provided in the CLOSED BOX Tab....as well. as in the COMPARE Tab.

In the VENTED Menu, a STANDARD Design will be displayed. To investigate Alternatives, enter User Data in the BLUE Entry Fields, incl info re. Damping Material and Leakage, as well as the desired amount of an Amplitude Hump you want just above the Rolloff Frequency [e.g. 1.0 up to say 3.0 dB]. Then Click on "Optimize Fb for wanted peak" [Fb is the BOX Tuning Frequency] so it will calculate the Box Design. Be sure to click on UPDATE for Graphs and Frequency Response. Additional Performance Charts are provided in the VENTED BOX Tab....as well. as in the COMPARE Tab.

I addressed PROS and CONS of CLOSED vs VENTED in an earlier post using a specific Peerless 12-in Woofer Example. CLOSED has advantages of fewer Rebound Transients, and typically can pump out MORE POWER well BELOW the Roll-Off Frequency due to better Xmax Control (Maximum Excursion of the Voice Coil)....so carefully look at the two Alternatives in the COMPARE Tab:
Speaker ticking noise

FYI: Those are NOT HUGE Boxes...hence the above recommendation to use SEPARATE Box for each 18-in Driver:
1 liter = 0.03532 cu ft
1 cu. ft. = 28.31 liters

PS: MULTIPLE Sub-Woofers should be in DIFFERENT locations so that they excite the various Room Modes DIFFERENTLY, which helps to smooth out the overall Low Frequency Frequency Response.

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post #11 of 57 Old 08-16-2017, 10:44 AM
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shrink em a bit, tune a little higher, and add a third
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post #12 of 57 Old 08-16-2017, 10:51 AM
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Idk, horn load the Mach 5 audio 32" sub

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post #13 of 57 Old 08-16-2017, 11:20 AM
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With that much room, wouldn't a more efficient design like a folded horn make for higher SPL without giving up frequency response?
http://audiojudgement.com/folded-horn-speaker-design/
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post #14 of 57 Old 08-16-2017, 11:30 AM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post
given your setup, i assume bang for the buck is important here?


~21 cubic feet (net internal volume) with 4x 2.5"x48" long ports will tune it to around 12hz or so. plugging one port will drop tuning to around 10hz. cabs would be about 30" x 30" x 48" to allow a little wiggle room and to allow a little spacing for wiring on the back. keeping the cabs to 48" tall should help with cutsheet optimization. at ~30" width for all the main panels, they will fit 3 per sheet with little waste that can be used for bracing, so overall, i don't think a ton of material goes in the dumpster with this one.


brace them up bigtime. :-)







the um18 would be a good choice for this application, powered along with an inuke6000dsp amp.
with 1100 watts or so to each driver, this is roughly 2pi space response (outdoor model, no room gain).
with room gain, you'll probably be flat or possibly rising somewhat to 10hz.
one sub probably overkills your mains, but 2 subs...just because. :-)





the big problem (to the extent that there is any) with notnyt's build is it required lifting the second cab on top of the first (and his drivers are beastly on top of that, 2 per cab).


with these, even though they would be heavy, they would be manageable. carpet sliders could ease sliding them in and out of place.


this is just a first pass concept. calculations would have to be refined if proceeding.
You are right about bang for the buck, and this concept makes a lot of sense.

Please pardon my ignorance on these questions:
1. Do I need to keep any sort of minimum space between the cabs and the surrounding walls, or is it the distance from the driver to the wall(s) what's important?
2. Is it normal to pair a 6000DSP with only 2 UM18s? Is there a benefit to stuff 2 drivers in each of these cabs, even if it requires more amp?
3. The cabs are 48" high and 30" deep. Were you achieving the 48" long ports by having them turn 90 degrees at the back of the cab?
4. Why do you use 4 ports instead of just 1 or 2 bigger one(s)? For bracing purposes or to achieve the low tune?

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Base Layer - Pioneer Andrew Jones (2nd gen) 2xFS52+1xC22+2xBS22
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post #15 of 57 Old 08-16-2017, 01:30 PM
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"1. Do I need to keep any sort of minimum space between the cabs and the surrounding walls, or is it the distance from the driver to the wall(s) what's important?"

no minimum space between the cabs and the walls is required. if you want to build the cabs to completely fill in the space, that would be fine. I'm not sure that I understand what you are asking about the driver distance to the walls. moving the drivers around on the baffle will create minor changes in response. i just stuck them in the middle for aesthetics.


"2. Is it normal to pair a 6000DSP with only 2 UM18s? Is there a benefit to stuff 2 drivers in each of these cabs, even if it requires more amp?"

the 6000dsp works well with one um18 per channel. the amp puts out about 1100 real watts or into about 4 ohms, which is also the impedance of the um18 driver (with coils in series). going to 2 drivers per cab would require adding a second amp or using a much more powerful from the outset. the benefit of double um18's/6000dsp's per cab would be about 5-6db of gain in output at the upper end and declining to somewhere around 4db or so (depending on port compression) down into somewhere in the mid-teens or so. then box size, port compression, at the tuning frequency would probably limit gains to 2-3db or right around the tuning point.


"3. The cabs are 48" high and 30" deep. Were you achieving the 48" long ports by having them turn 90 degrees at the back of the cab?

yes. that is a form factor that has proven very successful over hundreds of builds.


"4. Why do you use 4 ports instead of just 1 or 2 bigger one(s)? For bracing purposes or to achieve the low tune?"

both. with big cabs, lots of bracing is required for best results. the braces in the ports keep the bottom panel in the main body rock solid. a side benefit of four ports is that one port can be closed off "stuffed" to lower the tune. in this case all open is around 12 hz, one stuffed would give 10hz.
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post #16 of 57 Old 08-16-2017, 01:35 PM
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EL Gigante ...... @LTD02

Link to budget Home Theater build

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post #17 of 57 Old 08-16-2017, 02:09 PM
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For a much simpler build which would get you all the volume you need, consider a couple 30" diameter sonosubs. 30" diameter x 45" tall = 46 cf each. No worries about the bracing, they'll be much lighter, and you could do a couple dual-opposed builds for 4 drivers total.
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post #18 of 57 Old 08-16-2017, 02:32 PM
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First - about that alcove. An alcove is a cavity in a room and as such it has it's own resonances. Quite similar to a closet - if you step into a closet you get a massive bass boost. But the thing is, if you fill in that alcove with sub boxes there won't be an alcove, no cavity with no cavity resonances. If you change the room it won't act the same as it did before, and filling in an alcove definitely counts as changing the room.

Second - if it were me I'd be doing large ported, large slot loaded / ported (like Ricci's MAUL and SKHorn) or large horn. I'd likely design my own because that's what I do but if you don't want to you could check out the MAUL and the Submaximus or LTD02's ported design that he just posted. The first two won't get quite as low as 10 hz but they are proven designs and that's worth a lot. There's also lilmike's design collection but I don't know which is the lowest tuned.
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post #19 of 57 Old 08-16-2017, 02:43 PM
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You need about 130db to do 10hz any justice.

10-200hz @ 130db is a good target for a high-end diy system. (That's the threshold of pain above 40-ish Hz.)

For a big room like that you'll need 4 24's or 8 18's (as a starting point).

Distance law and pressure per sq inch etc

Definitely do lots of smaller boxes. 8 10cuft is better than 1 80cuft, from a portability and placement perspective...

Nyt's boxes, the ZOD and my HzHorn is definitely as big as you'd ever really want to go (dolly, engine lifter, and pully system required).
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post #20 of 57 Old 08-16-2017, 03:43 PM - Thread Starter
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Here is the result of some REW sweeps as well as another photo of the "alcove", which maybe is the wrong word to describe it. Hopefully the photo helps. The sweeps were done at different MV levels (-20, -10, -5, and 0) as I wanted to see if the response would be consistent.
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post #21 of 57 Old 08-16-2017, 03:50 PM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post
You need about 130db to do 10hz any justice.

10-200hz @ 130db is a good target for a high-end diy system. (That's the threshold of pain above 40-ish Hz.)

For a big room like that you'll need 4 24's or 8 18's (as a starting point).

Distance law and pressure per sq inch etc

Definitely do lots of smaller boxes. 8 10cuft is better than 1 80cuft, from a portability and placement perspective...

Nyt's boxes, the ZOD and my HzHorn is definitely as big as you'd ever really want to go (dolly, engine lifter, and pully system required).
I assume that despite a target of 10-200hz @ 130db, you don't actually listen at those levels?!? I can understand why having more headroom than your max listening levels would be a good thing, as you wouldn't be stressing the sub by bringing it to its absolute limits. Is that the reasoning for wanting such crazy output levels?

That headroom benefit aside, if watching movies at reference which have max 115db on LFE, is there any reason to need your sub to be capable of more output than that? I'm not doubting the headroom benefit, just want to make sure I fully understand the situation.

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post #22 of 57 Old 08-16-2017, 05:11 PM
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You sure thats 11,000 ft3 ?


Thats as big as most houses.......with no walls inside.....my entire 1 bedroom house is only 5000ft3 including kitchen,bath and closets......

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post #23 of 57 Old 08-16-2017, 07:01 PM - Thread Starter
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You sure thats 11,000 ft3 ?


Thats as big as most houses.......with no walls inside.....my entire 1 bedroom house is only 5000ft3 including kitchen,bath and closets......
Yes, most of my house is this 11,000 cf space. Very open layout. Rough dimensions that I used to calculate the volume are 21'x33' with 20' high cathedral ceiling. The cathedral angle starts 12' from the floor.
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Originally Posted by aron7awol View Post
I assume that despite a target of 10-200hz @ 130db, you don't actually listen at those levels?!? I can understand why having more headroom than your max listening levels would be a good thing, as you wouldn't be stressing the sub by bringing it to its absolute limits. Is that the reasoning for wanting such crazy output levels?

That headroom benefit aside, if watching movies at reference which have max 115db on LFE, is there any reason to need your sub to be capable of more output than that? I'm not doubting the headroom benefit, just want to make sure I fully understand the situation.
Spoiler!
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Spoiler!
There is no happy dance or Meme that can represent the amount of awesome basstastic feeling I get from your post....vids and set up......I could repeatedly stick my hand in a meat grinder until it was a stump and it would not represent how stoked that level of bass makes me feel.


Fantastic recording quality also compared most vids !!!!!

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post #26 of 57 Old 08-17-2017, 03:17 AM
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I assume that despite a target of 10-200hz @ 130db, you don't actually listen at those levels?!? I can understand why having more headroom than your max listening levels would be a good thing, as you wouldn't be stressing the sub by bringing it to its absolute limits. Is that the reasoning for wanting such crazy output levels?....

In this forum, crazy is a relative term.



"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
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Is the output I am getting from a single vtf-15h mk2 surprising, confirming my suspicion that my alcove creates an unusual amount of boundary gain?

Given that the um18s are backordered, would using HT-18 V2s and doubling up make sense? Can a 6000DSP drive 4 HT-18s? It looks like the 2 drivers can fit in a 30"x30"x48" box.

After seeing BassThatHz comment "You need about 130db to do 10hz any justice." I am questioning if maybe I set my sights too high (or low in this case) aiming for 10 Hz? Does my suspended floor change the math? At what frequency can 120db do justice? Maybe I'm better off going for a slightly higher tune (as some people have already suggested) if I'm going to build a system that can "only" output 120db?

I have a couple of good carpenters that work for my company often that I could have build the enclosures for me. If I did go with the 30"x30"x48" design, is there a cut list or any other plans that already exist that I could give them?

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Originally Posted by aron7awol View Post
Is the output I am getting from a single vtf-15h mk2 surprising, confirming my suspicion that my alcove creates an unusual amount of boundary gain?

Given that the um18s are backordered, would using HT-18 V2s and doubling up make sense? Can a 6000DSP drive 4 HT-18s? It looks like the 2 drivers can fit in a 30"x30"x48" box.

After seeing BassThatHz comment "You need about 130db to do 10hz any justice." I am questioning if maybe I set my sights too high (or low in this case) aiming for 10 Hz? Does my suspended floor change the math? At what frequency can 120db do justice? Maybe I'm better off going for a slightly higher tune (as some people have already suggested) if I'm going to build a system that can "only" output 120db?

I have a couple of good carpenters that work for my company often that I could have build the enclosures for me. If I did go with the 30"x30"x48" design, is there a cut list or any other plans that already exist that I could give them?
Hi,

you are already getting some very good technical advice from some very qualified people. But, I would like to offer a couple of other perspectives on this. First, I wouldn't worry about trying to "pressurize" 11,000^3 if I were you. Of more relative importance than the total SPL in the room is the amount of SPL in proximity to your listening position, so the distance from your alcove sub location to your MLP is of paramount importance in my opinion.

I also think that it does matter that you are on a suspended floor as that will increase your perceived tactile energy. FWIW, I think that most people can be very happy with subwoofers that hit about 14Hz or 15Hz at high SPL, with good tactile response. Anything below that in frequency, and above about 120db, is just gravy for most of us. So, with respect to port tune, I might shoot for 14Hz or at the most 12Hz, if I had any concern about building subs that would deliver what I wanted in SPL with a 10Hz port tune.

Finally, there is something I was thinking when I was reading this thread yesterday, although I hadn't planned to comment. I probably wouldn't compromise too much on performance in order to hold down costs. You don't want to finish a project this large only to wish that you had gone a little further with either the size or number of drivers, or with the amplifier power. That struck me when you were discussing the capabilities of the 1100 watt RMS amplifier that you are considering. By comparison, the Cap 4000 ULF with its twin 18" drivers and roughly 40" by 40" by 20" cabinet has a 4000 watt RMS amp. And, there are people with two of those in rooms much smaller than 11,000^3. So, I would probably aim high here if I were you, and then rely on the technical expertise of the other people commenting to help get me where I really wanted to go.

Regards,
Mike
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post #29 of 57 Old 08-17-2017, 11:36 AM - Thread Starter
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Hi,

you are already getting some very good technical advice from some very qualified people. But, I would like to offer a couple of other perspectives on this. First, I wouldn't worry about trying to "pressurize" 11,000^3 if I were you. Of more relative importance than the total SPL in the room is the amount of SPL in proximity to your listening position, so the distance from your alcove sub location to your MLP is of paramount importance in my opinion.

I also think that it does matter that you are on a suspended floor as that will increase your perceived tactile energy. FWIW, I think that most people can be very happy with subwoofers that hit about 14Hz or 15Hz at high SPL, with good tactile response. Anything below that in frequency, and above about 120db, is just gravy for most of us. So, with respect to port tune, I might shoot for 14Hz or at the most 12Hz, if I had any concern about building subs that would deliver what I wanted in SPL with a 10Hz port tune.

Finally, there is something I was thinking when I was reading this thread yesterday, although I hadn't planned to comment. I probably wouldn't compromise too much on performance in order to hold down costs. You don't want to finish a project this large only to wish that you had gone a little further with either the size or number of drivers, or with the amplifier power. That struck me when you were discussing the capabilities of the 1100 watt RMS amplifier that you are considering. By comparison, the Cap 4000 ULF with its twin 18" drivers and roughly 40" by 40" by 20" cabinet has a 4000 watt RMS amp. And, there are people with two of those in rooms much smaller than 11,000^3. So, I would probably aim high here if I were you, and then rely on the technical expertise of the other people commenting to help get me where I really wanted to go.

Regards,
Mike
The distance from my alcove sub location to my MLP is about 7 feet, so it seems to be close enough that it's worth putting there and taking advantage of the boundary gain. When I initally placed my sub there, I first tried many different locations throughout the room and that location had by far the best response at the MLP. After reading about the benefits of nearfield subs, I recently moved it directly behind my MLP as a test, and was extremely disappointed in the performance compared to the alcove location. I came to the conclusion that the nearfield location I tried was either in a null or the alcove location is just so optimal in my room that no other location could compare to it, so I moved it back. I also tested a bunch of locations within the alcove at the same time and settled on its current location.

I don't plan on ever listening above reference, so I'm thinking that a target of a flat response at 120db down to whatever frequency I'll be able to feel on my suspended floor at 120db. That would give me an extra 5db of headroom to stay in the sub's wheelhouse and reduce distortion. It seems like changing my tune is the right move for me, I'm just not quite sure what I should change it to.

I have looked at the Cap 4000 extensively, and read through the thread comparing it to similar DIY options. It seemed like the conclusion is that the modified drivers used in the Cap 4000 require the SpeakerPower amp because any lower cost amp wouldn't be able to drive them properly. I'm definitely not trying to skimp and end up with too little amp for the number of drivers, so I'm open-minded and would love to hear everyone's opinions.
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post #30 of 57 Old 08-17-2017, 12:39 PM
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If you only have one row and can put two 15hz ported 18's behind seats then you might have enough bass to make you happy-er. A single nu6kdsp can power two hst-18's.

You'll also want two 50hz ported PA-460's and an nu1000dsp bridged. These are nearly 100db per watt from 40-300hz, which is where all the drum hits and car explosions are at. A b&c 18 or 21 if you want slightly better mid-bass for 2-5x the cost.

<40hz is for rap music and earthquakes.
Which is the wheel house of the hst/uxl/lms.

Because of their efficiency pro drivers are about 10x louder and run cooler than high excursion subs. Just box model it.

In a higher-end system you really need both.

No matter what you build... it will be better than the sub you have now or any sub you could purchase.

You need 110db to hear 10hz, 100db to hear 15hz and 90db for 20hz.
At 0-10% thd.
These are minimums...
Ear damage is around 140-170db in that region, you'll be nowhere near it.
Above 50hz you might be though. But that's what volume knobs are for!

If you have multiple rows, corner loading or wall loading is the next loudest config. With drivers and ports facing the walls.

The rule of thumb is that the system must get twice as beefy for each doubling of distance beyond 1m.
This law applies to radar and radios as well.
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