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Deep Sea Sound
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Archaea - Top notch post...thanks so much.

Glad to hear the tee-nuts worked for you but I get scared they'll come out or shred the wood so I went a slightly different route with my sub builds.

http://shop.stafast.com/sl14205h2130

I use a pair of small screws to hold them in place so I won't have to worry as much as I would with a tee or hurricane nut.
 

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Deep Sea Sound
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Archaea - Top notch post...thanks so much.

Glad to hear the tee-nuts worked for you but I get scared they'll come out or shred the wood so I went a slightly different route with my sub builds.

http://shop.stafast.com/sl14205h2130

I use a pair of small screws to hold them in place so I won't have to worry as much as I would with a tee or hurricane nut.
I like it, thanks!
 

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Discussion Starter #389
not exactly --- let's split the difference. It's more like a ~3 ohm load on an amp that is spec'ed to do only 4ohm or higher. :D


The impedance graph (ohm/resistance plot) shows the UM18-22 to be a six ohm subwoofer above about 7hz. So I'm only running the subs in parallel as a pair at about a combined minimum of a 3ohm load above 7hz.

My workaround is the HPF which eliminates those frequencies which have the lowest ohm rating. Without the HPF - I easily overwhelm the amp with too little resistance and it power cycles, even at low volumes. With the HPF- no problems.


Ultimax UM-18 impedance chart is in bottom right for reference.
http://www.parts-express.com/pedocs/specs/295-518--um18-22-spec-sheet.pdf
 

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Discussion Starter #390
A little update.

I was tired of messing with the impedance limitations of the iNuke Amp paired with the UM18-22 when trying to run two subs per channel on the iNuke DSP 6000 (which is out of spec).
I now have three iNuke amps powering five sealed UM18-22 subwoofers up front.
2 iNuke DSP 6000's running 1 sub per channel (4 subs powered this way)
1 inuke DSP 3000 running 1 sub bridged (1 sub powered this way)
all split off the same subwoofer 1 output signal from the Onkyo PR-SC5508 prepro.


And my nearfields are disassembled because I'm going to rewire three of them to 1ohm so I can bridge those three off a Cerwin Vega CV-5000 amp. This will give each nearfield about 1650 watts on the 5K of output. I'll use a Symetrix 551E to provide PEQ to nearfield.

I post simply to provide an update of my experience on these sealed. Last night I spent several hours listening to well known demo clips with the front five subwoofers properly powered -- Results --- I'd quite clearly take my pair of ported 2011 JTR Captivators over those five sealed. The output capacity of my former JTR Captivators is much higher, MUCH higher. The UM18-22 are getting nearly 2,000 watts each. No impedance issues now, yet I can tax out the amps (and therefore the drivers (since the amps tax out at about 2,000 watts per channel which is in line with the peak rating on the UM18-22) long before I get to reference because of my 6dB boost at 20hz PEQ (Q of 2) and my 3dB dynamic EQ LP6, and the fact I like to run my subs 6-10dB hotter than the mains. Because of my room's shape with the baffle wall, once again I'm getting very little boundary gain because my subs are out about 6-8 feet from the cement wall -(since I have a baffle wall) --- therefore even with my PEQ boost and my Dynamic EQ boost, I'm still not flat to 20hz, or below. When I watch my demo scenes at -8dB with the subs 6-10 dB hot that's about all my amps/subs have in them when just the five are playing along the front wall. I could always run the same demos on the Captivator pair at reference with the subs 6dB hot in my old room and have no troubles with my proper HPF in place. To get to those same volumes - I'd have to cut out all my sealed sub boost and --- well then I'd rather just have the JTR ported Captivators - because I'm completely lost the benefit of the sealed. I've tapped them out, and they are insufficient for my listening preferences. (I know the subs are being fed their limit now because I ran some short 5hz test tones checking for air leaks at 4 signal lights, for like 30 seconds??? --- when I took the sub out after finding a leak - the smell of hot subwoofer/electronics was very present - so I feel comfortable knowing they can't handle much more power if they smell like that so quickly with what power they have currently.) I'm looking forward to @Ricci data-bass test on these UM18-22 to see how they do.
Conclusion: If I only had five of these subs I would be sorely disappointed right now.

NEARFIELD SUBS change the whole game though. With a sub right behind me I'm plenty satisfied with the sealed experience, and I think I'd need a lot less to be overall satisfied if they were only nearfield. Honestly, with my experiences in playing with this gear ---- I think if I had my druthers I'd take one or two sealed nearfield firing right into my back with a low crossover (like 60 or 70hz) over eight of the same drivers in the front of the room. Nearfield is just that good. So the current plan is to have five subs in the front of the room arranged under the screen, and three subs nearfield, immediately behind the three main theater seats. It is critical, IMO, that the driver is centered on the chair, and as close as possible, and firing right into your back. It is the only way I see any value at all in subsonic frequencies. You can feel them nearfield, you can't hear them, you can't flood your room with them in mass - but placed nearfield you get the subsonic ULF tactile effect and it is cool.
 

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Not sure why you expected sealed subs to have more output than ported...?

Switch your um18-22 to ported and it's a whole 'nother level for output.

You're comparing five sealed 18"s to four ported 18"s? Ported should have like 9 dB advantage around tune.

The "benefit" of sealed is much smaller cab sizes, and lower extension. Lower extension is a tradeoff of output.
 

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Not sure why you expected sealed subs to have more output than ported...?

Switch your um18-22 to ported and it's a whole 'nother level for output.

You're comparing five sealed 18"s to four ported 18"s? Ported should have like 9 dB advantage around tune.

The "benefit" of sealed is much smaller cab sizes, and lower extension. Lower extension is a tradeoff of output.

He was talking about 2 ported subs not 4, and he has a total of 8 sealed subs.
 

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Discussion Starter #393 (Edited)
@Bassment,

Carps right. I only ever had two ported captivators --- but i'm pretty confident it would take at least six, maybe eight sealed UM18-22 to even meet/beat the Caps performance level pretty much regardless. I don't think four would meet or beat in any room/regardless of boundary gain. The 2011 Captivator drivers I had were the same the Orbit Shifter uses.

JTR mates that driver with a 4000 watt speaker power amp, and his site states the sub should be good for 7,200 watt peak.

The UM-18 is 88dB efficient
The JTR driver was in the mid 90s efficiency IIRC, and Jeff states well over 100dB sensitive towards 100Hz.

So right out of the gate - with one watt applied it is at least 50% louder, maybe 2x's as loud based on the efficiency alone.

The JTR driver takes basically four times the power, and has about 50% more usable excursion.

So that's another doubling of volume based on power handling and excursion.


All that to say it's more than just the 9dB difference you get from going from a sealed box to a ported box.

Basically, - 2 things ---
1) even though I knew the lay of the land when I started this project - - - I'm surprised by how little output (if you try for a consistently flat FR, and don't get a load of free boundary gain) multiples of these sealed compare to monster ported subs.
2) thank goodness for nearfield


A co-worker who came to visit my place recently said I should ditch the sealed and go back to the Captivators that he had previously heard after listening to both ported caps and all eight sealed. @JDontee visited my new space, and basically said he remembered the 2 ported caps being more savage/tactile than the eight sealed. Since their visits I've reworked the amps - as mentioned a few posts back because it was in the back of my head that maybe it was just the fact that I was underdriving the subs with a mismatched impedance load and the amps were failing earlier than they should/could - if they were properly matched.

That's not the case...That's the experimentation I was doing last night.

I've considered dumping these and going with a pair of gjallarhorns - or a pair of Orbit Shifters or something - but Scott Simonian is right. Once you get to these levels the only time I need more output is for ear splitting demo volumes, and with a horn sub you have to navigate avoiding resonant frequencies, and lesser placement options, and lacking full bandwidth sound capability. It just sucks that to you would have to double down on subs, and amps to get 6dB more --- which might be my point of desire.

But --- back to reality - - the eight sealed UM18-22 fit my need/want, especially with a few near field and will probably stay a long time - I'm just reporting that if I, personally, had less than eight of these UM18-22 - I'd be disappointed with the outcome when compared to my pair of JTR ported Captivators. I'm going to hook up the three sealed nearfield today and get back to enjoying that tactile experience!
 

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Ah, I thought captivators were the dual driver one.

Even comparing 2 ported to 5 sealed, Ported will be louder at tune.

You're right about needing 8 sealed to be super impressive I think. That's why you see lots of set-ups around here with 8 or 16 sealed subs :p

So with all 8 going, the 8 sealed are better than the 2 ported though right?
 

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Deep Sea Sound
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No offense but it depends on which 8 subs. In comparing 2 of my previous LMS-5400s to quad SI HT18, that was about equivalent (same wattage). Beast still has the best sounding theater I've heard with 8 HT18s but 4 HST-18s/LMS-5400s or 2 HS24s would be about equivalent...at least based on my personal experience. Still haven't heard the Orbit Shifter but I'll probably head over to Asoofi1s place at some point to get that experience. :)

So if you want to scale down to 2 subs, you could go with the Orbit Shifters or the HS24s. Note, I know the Orbit Shifters might have more output above tune but a pair of HS24s should be pretty close to what most rooms need...in comparison to 8 18s. But this is all conjecture. :D
 

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Discussion Starter #397
A pair of orbit shifters pretty much has to be experienced to believe.


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I got the Cerwin Vega plugged in bridged to three nearfield subs at 3ohm load. Nearfield is nice now, VERY nice.
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dgage, these ultimax UM18-24 subs should best the SI 18HT slightly --- but yes I know what you are saying. One counter point - I've heard a pair of JTR ported caps vs. a pair of sealed LMS-5400 at Gorilla83s. It wasn't close. Not that it should be when comparing output ported vs. sealed two on two - but the LMS 5400 pair in sealed boxes fell hard to the ported JTR Captivators in regards to clean output. @popalock brought the LMS-5400 to the meet - they were in his wolly mammoth boxes.






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This is the first time I've had all my subs properly powered. Going to take a break --- since I just got it setup and will give it some demo time this week.
 

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A pair of orbit shifters pretty much has to be experienced to believe.


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I got the Cerwin Vega plugged in bridged to three nearfield subs at 3ohm load. Nearfield is nice now, VERY nice.
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dgage, these ultimax UM18-24 subs should best the SI 18HT slightly --- but yes I know what you are saying. One counter point - I've heard a pair of JTR ported caps vs. a pair of sealed LMS-5400 at Gorilla83s. It wasn't close. Not that it should be when comparing output ported vs. sealed two on two - but the LMS 5400 pair in sealed boxes fell hard to the ported JTR Captivators in regards to clean output. @popalock brought the LMS-5400 to the meet - they were in his wolly mammoth boxes.

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This is the first time I've had all my subs properly powered. Going to take a break --- since I just got it setup and will give it some demo time this week.
Ahhh yes. Looking back on that experience... I don't know if the LMS-U's could have been anymore nutered. Remember the graphs you took? I brought the LMS-U's in different sized boxes to see what the real world response difference would look like. ~2.5ft^3 box was down a notable about from the 4.2ft^3 box:


If I only knew then, what I know now... I could have at least saved myself several hours of laboring to make a box last minute and just ran the sim in winISD...lol/

Learned a lot since that GTG. If I could have done it all over again, the LMS-U's would have had a MUCH better showing.

That said, they STILL would have been dominated by the Caps...

:D
 

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How does the um18-22 in a Marty/Mini Marty box compare to the JTR Caps?

I'm wanting to build two near field end tables, sealed, using FTW-21's... To pair along with my two um18-22 mini Marty's... But instead of another 6000dsp, I'm debating on getting a lab grupen clone... But I'm not sure if that's the way to go...
 

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Deep Sea Sound
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Ahhh yes. Looking back on that experience... I don't know if the LMS-U's could have been anymore nutered. Remember the graphs you took? I brought the LMS-U's in different sized boxes to see what the real world response difference would look like. ~2.5ft^3 box was down a notable about from the 4.2ft^3 box:


If I only knew then, what I know now... I could have at least saved myself several hours of laboring to make a box last minute and just ran the sim in winISD...lol/

Learned a lot since that GTG. If I could have done it all over again, the LMS-U's would have had a MUCH better showing.

That said, they STILL would have been dominated by the Caps...

:D
I agree with you completely, I've learned a ton in the last year...and still have a ton to learn. I think I know enough to start a sub company...we shall see. :)

And when I took my LMS-5400s to Beasts and put the pair against the HS24, they were bested by the single HS24. But later I put 4,000w to each instead of 2,400w and that really made a difference. The HS24 might have still won but it would have been close, at least above 15Hz.
 
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