I've been at a stand still for a while now and just don't want to mess this up. I can build subs, but am unsure of modeling them correctly. I've been searching google, other forums, Facebook groups, etc and still not getting solid answers. A lot of things are around smaller sealed subs, but I know that isn't the route I want to take.
The UM15 specs state that it needs a 11.1 cuft vented box for an F3 of 17Hz. That is a pretty big box, but if it *needs* to be that large, then so be it. I will try to work it into my room and hope for minimal complaints from my wife. LOL
The problem is, what about port length? How do I calculate the port size/length or vent size/length?
Do I really need an 11.1 cuft box to really be effective?
Other notes:
I have two UM15-22s new in box that I acquired cheap, thus the reason I am looking at them vs. some 18" models.
I will be powering two of these sub builds with a NX3000D.
Pretty much 100% movie usage.
Room is just over 2500 sqft in volume.
Currently I am using a SVS 20-39PCi sub and a DIY clone of the same.
Plan it to try to put the new UM15 builds behind my 2nd row of seats where I have about 27" of depth to work with, and plenty of height and width, but again, 11.1cuft boxes are pretty large (and heavy).
I *might* be able to put the builds behind my false wall/screen wall, which gives me about 30" of depth, 30" of max width, and fairly unlimited height.
Please help.
Thank you.
The UM15 specs state that it needs a 11.1 cuft vented box for an F3 of 17Hz. That is a pretty big box, but if it *needs* to be that large, then so be it. I will try to work it into my room and hope for minimal complaints from my wife. LOL
The problem is, what about port length? How do I calculate the port size/length or vent size/length?
Do I really need an 11.1 cuft box to really be effective?
Other notes:
I have two UM15-22s new in box that I acquired cheap, thus the reason I am looking at them vs. some 18" models.
I will be powering two of these sub builds with a NX3000D.
Pretty much 100% movie usage.
Room is just over 2500 sqft in volume.
Currently I am using a SVS 20-39PCi sub and a DIY clone of the same.
Plan it to try to put the new UM15 builds behind my 2nd row of seats where I have about 27" of depth to work with, and plenty of height and width, but again, 11.1cuft boxes are pretty large (and heavy).
I *might* be able to put the builds behind my false wall/screen wall, which gives me about 30" of depth, 30" of max width, and fairly unlimited height.
Please help.
Thank you.
OK, done right 'we' need a complete, dimensioned, finished room floor plan and at a glance looking at ~14 ft^3 exterior dims/sub due to high Vas, Xmax, pretty high Qts and will be some form of TL since an optimized BR will need a large, ~100" long vent unless you opt for dual 18" PRs/sub, then the cabs can be ~5.5 ft^3 NET based on published specs.
GM
GM
The room is 13.5 feet wide, 24 feet long and just 7 feet 9 inches tall for a sqft of 2,511.
I haven't heard of anyone building these into a box larger than 11.1cuft (since that it the enclosure size of the spec sheet), and I was hoping to make them a little smaller without compromising too much. I know that is relative and subjective. My last sub build was just over 5cuft and my wife was happy to see it get hidden behind my acoustically transparent false screen wall, so to prevent being kicked out of the house completely, as well as for practical reasons around just sure weight and moveability of the subs, I can't see being able to go to 14cuft with 2 subs.
I just thought that I would state that now before anyone did any modeling.
Thanks.
I haven't heard of anyone building these into a box larger than 11.1cuft (since that it the enclosure size of the spec sheet), and I was hoping to make them a little smaller without compromising too much. I know that is relative and subjective. My last sub build was just over 5cuft and my wife was happy to see it get hidden behind my acoustically transparent false screen wall, so to prevent being kicked out of the house completely, as well as for practical reasons around just sure weight and moveability of the subs, I can't see being able to go to 14cuft with 2 subs.
I just thought that I would state that now before anyone did any modeling.
Thanks.
I have read elsewhere that smaller sealed boxes with the Ultimax UM15-22 usually leaves people wanting more for movie playback.
I get pretty good bass response through multiple listening positions in the room with my current 2 ported subs, particularly after I did some tuning with a MiniDSP for those. I want to see how smooth of a response I can get and if I can dig a little deeper. I've always been chasing that "thump in your chest" effect or the "moving of your pant legs" feeling (if you know what I mean), but just can't seem to get there without over-bloated sounding bass and LFE.
In an ideal situation, I would be able to replace my current 2 subs with these 2 yet-to-be-built subs and get me a little closer. I am just scared of the unknown to say that I will be able to drop the current 12" subs from the mix as I might (after a bit of tuning) really like the effect of 4 subs.
Right now I have both 12" subs up front between my large center channel and tower L/R. I tried one up front and one in the rear of the room and actually didn't like what I heard, but that was a few years before the MiniDSP entered the picture. Now, that would just be tricky to wire up due to lack of dedicated subwoofer runs in my walls to give each of the 12" subs their dedicated output on the MiniDSP like they have now (since they are co-located up front, I have 1 subwoofer run to the front of the theater, it goes into the MiniDSP, and then the MiniDSP sends 2 separate configured outputs, one to each of the subs.)
So I still want to go ported, and I know that will be a large box for each one (compared to the 5cuft I have for each now) but if these end up behind my 2nd row of seats, they will be visible and that is where the challenge comes in...
If my current 12" subs matched each other in looks (one being the SVS cylinder style, and the other being a taller box style that someone modeled for me to closely match the SVS, but still looks different), I could probably put the 15" subs up front and hide them which would give me some additional flexibility. Since the 12" ones look different, and my wife likes symmetry, the 15" will at least start in the back of the room. I guess I could sell the 12" subs and build 2 more subs at some point and count this as just another step towards increased bass performance instead of the final stop on this path...
I get pretty good bass response through multiple listening positions in the room with my current 2 ported subs, particularly after I did some tuning with a MiniDSP for those. I want to see how smooth of a response I can get and if I can dig a little deeper. I've always been chasing that "thump in your chest" effect or the "moving of your pant legs" feeling (if you know what I mean), but just can't seem to get there without over-bloated sounding bass and LFE.
In an ideal situation, I would be able to replace my current 2 subs with these 2 yet-to-be-built subs and get me a little closer. I am just scared of the unknown to say that I will be able to drop the current 12" subs from the mix as I might (after a bit of tuning) really like the effect of 4 subs.
Right now I have both 12" subs up front between my large center channel and tower L/R. I tried one up front and one in the rear of the room and actually didn't like what I heard, but that was a few years before the MiniDSP entered the picture. Now, that would just be tricky to wire up due to lack of dedicated subwoofer runs in my walls to give each of the 12" subs their dedicated output on the MiniDSP like they have now (since they are co-located up front, I have 1 subwoofer run to the front of the theater, it goes into the MiniDSP, and then the MiniDSP sends 2 separate configured outputs, one to each of the subs.)
So I still want to go ported, and I know that will be a large box for each one (compared to the 5cuft I have for each now) but if these end up behind my 2nd row of seats, they will be visible and that is where the challenge comes in...
If my current 12" subs matched each other in looks (one being the SVS cylinder style, and the other being a taller box style that someone modeled for me to closely match the SVS, but still looks different), I could probably put the 15" subs up front and hide them which would give me some additional flexibility. Since the 12" ones look different, and my wife likes symmetry, the 15" will at least start in the back of the room. I guess I could sell the 12" subs and build 2 more subs at some point and count this as just another step towards increased bass performance instead of the final stop on this path...
I'm sure if you googled winisd and the driver, you'd find countless examples of others who've modelled this exact build.
Hmmm. Interesting idea. I was googling UM15, UM15-22, Ultimax 15 and then other words like Subwoofer Build, Subwoofer Box, Subwoofer Enclosure, Subwoofer Design, subsets of those words, etc...
I never thought about searching WinISD... I'll give that a shot. Thanks.
I have been reading through some threads and discussions, and most haven't yielded any useful information.
I did find 1 where a person built a 9cuft box and put a large slot in it: 4" tall, 24" wide, and 66" long...
That is a LONG port.
I found that post here actually:
Home theater subwoofers with UM15-22 drivers and Crown K2 amp
@Tintin1977 built this.
I did find 1 where a person built a 9cuft box and put a large slot in it: 4" tall, 24" wide, and 66" long...
That is a LONG port.
I found that post here actually:
Home theater subwoofers with UM15-22 drivers and Crown K2 amp
@Tintin1977 built this.
Maybe.
But will they be enough for you, in your room?
FWIW, I find a pair of sealed 8" midbass drivers to be adequate, but I'm not aiming to get close to "reference" levels.
Chris
You're welcome!
OK, but without all the other info............
This is a NET volume, i.e. got to add the huge 12" dia. vent required [dual 4" ain't gonna cut it for T-Rex, etc.] to get a low vent mach [speed] at high power [if no PRs] plus the driver + bracing that adds another ~6 ft^3!
Regardless, 'sounds' like either sealed and maybe buying a couple more or buying [4] 18" PRs or different, less powerful sub woofers with specs favoring small vented cabs or building a bunch of small standard power subs to spread around the room and DSP them to 'match', 'fit' the room's acoustics [best choice overall IME].
Another [once?] favorite option is/was a false front stage sub system or behind the screen variant to perch the mains/whatever on.
GM
11ft3 is just one particular (auto-generated) alignment AFAIK. It can recommend nonsensical values, depending on the t/s parameters of the driver. Also on the page is the following recommendations:
Here are 4 sizes in winISD, all tuned to 16.2hz, excursion peaks matched in level via highpass, then excursions limited to approx xmax+10% via power, vents sized to keep max velocity under 17m/s:
15.2 ft3, 110.5db, 650w, 17.0hz, 7.6"x25", 1125in3 (.65ft3), 271hz
11.0 ft3, 108.8db, 725w, 17.0hz, 7.0"x31", 1193in3 (.69ft3), 221hz
08.0 ft3, 107.0db, 800w, 17.0hz, 6.3"x35", 1085in3 (.62ft3), 192hz
06.0 ft3, 105.0db, 800w, 16.5hz, 5.7"x39", 0994in3 (.57ft3), 172hz
read as:
net volume not including port/materials/bracing, db@16hz, Power required, highpass (2nd order bw), port dimensions (diameter x length), port volume (air only, not including material), port resonance frequency
Note I am not promising these vents won't 'chuff''; I don't know how to work Flare-It well enough yet to tell anything, so I am just simplifying to 17m/s max velocity. Insert dog-at-keyboard meme here because I'm an amateur 😛
TL;DR: it takes ~15ft3 to get 'flat to 16hz', and is a cs3/cs4 Chebyshev alignment for whatever that's worth. Something significantly smaller may also fit your needs. If you are still considering going big; how about a riser platform for a rear seating position? Gets them closer to you as well as a way to 'hide' them.
Here are 4 sizes in winISD, all tuned to 16.2hz, excursion peaks matched in level via highpass, then excursions limited to approx xmax+10% via power, vents sized to keep max velocity under 17m/s:
15.2 ft3, 110.5db, 650w, 17.0hz, 7.6"x25", 1125in3 (.65ft3), 271hz
11.0 ft3, 108.8db, 725w, 17.0hz, 7.0"x31", 1193in3 (.69ft3), 221hz
08.0 ft3, 107.0db, 800w, 17.0hz, 6.3"x35", 1085in3 (.62ft3), 192hz
06.0 ft3, 105.0db, 800w, 16.5hz, 5.7"x39", 0994in3 (.57ft3), 172hz
read as:
net volume not including port/materials/bracing, db@16hz, Power required, highpass (2nd order bw), port dimensions (diameter x length), port volume (air only, not including material), port resonance frequency
Note I am not promising these vents won't 'chuff''; I don't know how to work Flare-It well enough yet to tell anything, so I am just simplifying to 17m/s max velocity. Insert dog-at-keyboard meme here because I'm an amateur 😛
TL;DR: it takes ~15ft3 to get 'flat to 16hz', and is a cs3/cs4 Chebyshev alignment for whatever that's worth. Something significantly smaller may also fit your needs. If you are still considering going big; how about a riser platform for a rear seating position? Gets them closer to you as well as a way to 'hide' them.
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If they can be ran significantly past xmax, here is what the bigger boxes look like at the full 800w rms. Not much different. I didn't recalculate the new port volumes. 8 and 6 ft3 stay the same as above.
15.2 ft3, 111.3db, 800w, 8.0"x28", 242hz
11.0 ft3, 109.1db, 800w, 7.1"x32", 215hz
P.s. I didn't have 'simulate voice coil inductance' turned on for any of these, but they don't look any different under 30hz either way. Also, being winISD, these are 2pi outdoor-on-the-ground models; room gain + corner loading would boost the lowest frequencies significantly. So ignore my flat-to-16hz comment above 😉
15.2 ft3, 111.3db, 800w, 8.0"x28", 242hz
11.0 ft3, 109.1db, 800w, 7.1"x32", 215hz
P.s. I didn't have 'simulate voice coil inductance' turned on for any of these, but they don't look any different under 30hz either way. Also, being winISD, these are 2pi outdoor-on-the-ground models; room gain + corner loading would boost the lowest frequencies significantly. So ignore my flat-to-16hz comment above 😉
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IME, a domestic-sized room will chop/change the LF response much more than smallish changes in cabinets.
The simulated -3dB point of my current speakers is around 50Hz, with a gentle (over-sized sealed box) rolloff below that:
At the listening position, I get something very different:
Best bet is to design for the desired LF extension, and have some EQ on-hand.
Chris
The simulated -3dB point of my current speakers is around 50Hz, with a gentle (over-sized sealed box) rolloff below that:
At the listening position, I get something very different:
Best bet is to design for the desired LF extension, and have some EQ on-hand.
Chris
