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Discussion Starter #1 (Edited)
Hey all,

In my research for my next HT sub build I started playing around with the Dayton Ultimax 18 in WinISD.

I found that a dual 18 cab tuned to 14.5Hz would be an enormous box (1100 Liters/38.8 cft) but the graph looked crazy impressive.

All of this is based on WinISD so please be gentle if I have done something wrong......
At full 2K power:
122db from 14.5Hz all the way up past 100Hz
3db down - 12.65Hz
10db down - 10.73Hz

24.25 M/s peak at 13.26HZ

3077823

Aside from the cab being huge (which is not an issue as we are building the HT with the new home so I have the ability to design the room anyway I want) is there a downside to using these Subs? I have had great luck in the past with Dayton drivers but I have also always gone on the inexpensive DIY side.
My plan is to build 2 separate cabinets with 2 18's in each. These would go in between my L/C/R behind the screen. and then build 2 more with single 18's for the back corners. (The ones in the back would be a powered cab and a slave unit)

Each set of 2 will prob be powered by a Speakerpower SP1-6000 plate amp.

As a side note, someone mentioned doing a SBA since we are building from scratch but I am not sure I want to go that route but options are still open.

Anyway once again I appreciate your time.

Jason
 

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If SBA is a real option,
you'll def want to look into the superlative work and resources here
 
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For a similar price be sure to look at the BMD Alpha II:


I would take two of these with NSW’s over 2 dual UMs. The UMs will not have the same impact in the midbass region. You can close one port for a 16Hz tune instead of the 19Hz tune if desired. A clone amp (FP20000q) would save you enough money to build 4. :D
 

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Discussion Starter #4
If SBA is a real option,
you'll def want to look into the superlative work and resources here
Yeah that was the thread I was pointed to before.

It looks really interesting but I'm not 100% sure its going to play as deep as I am hoping my HT subs will.

But honestly, like I said, I have no experience with one of these at all.

I am hoping to be able to hear one before we make final decisions, which truth be told, is not going to be for a bit so I have plenty of time to demo stuff.
 

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Discussion Starter #5
For a similar price be sure to look at the BMD Alpha II:


I would take two of these with NSW’s over 2 dual UMs. The UMs will not have the same impact in the midbass region. You can close one port for a 16Hz tune instead of the 19Hz tune if desired. A clone amp (FP20000q) would save you enough money to build 4. :D
And this is where my lack of knowledge is going to emerge.

In my current set up, I have my bass duties split up. The "musical bass" (50Hz to about 100Hz) is sent to four 8 inch woofers and the sub bass (50Hz and down) is sent to two 15 inch woofers. They are actively crossed over and EQ'd with a Mcintosh Mc2105 powering the 8's and a Mcintosh MC2120 powering the 15's. (My mains are Altec Lansing 617-8A playing everything from 100Hz up.)

My thought has always been the smaller the woofer the faster the reaction and the cleaner the end product will be.

And in this particular case it worked out really well but I am using a lot of "stuff" to get the woofers/subs to do what I want them to.

With that said I wanted to plan my theater around the same mind set where the subs are only going to be used to "move air" so we get that immersive chest crushing bass but all of the "musical" bass was reproduced by the mains.

I know pro series woofers are good for the upper range bass but they never model out to being able to play that DEEP bass I want in the HT. (Again, no real world experience with Pro Woofers so please take that into account when telling me I have no clue what I am talking about.;))

I know that horn subs (like the devastator) can assist in getting those low notes, but that is also something I have never played around with.

I have been looking at the Noesis 215RT's and the Danley SH50's for the mains and I know they can play down to 50Hz without issue so that means (I assume) that my Subs will only have to work in the lower regions only.

But I am sure that over the next couple of years as we plan for the house and the Home Theater things will go through a ton of changes.

I appreciate all knowledge that any of you wish to share.

Thanks again
Jason
 

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Small woofer fast bass is an old myth. Lots of very capable big drivers, motor force, design and inductance all play into good quality output and where it hits. The heavy cone, big motor, big coil, higher Le drivers (stereo integrity and the like) play lower, the lighter cone, low Le pro drivers are better at mid bass, as a generalization. Apparently the Harbottle 24 does it all from reading. I mean you could put four Harbottle 24 in less space sealed and it would destroy four 18s. Not same budget of course :) But the 24 in what is it 8 feet? Whole thing around 120lbs? The SI weighs 90 ish by itself? Anyway I digress.

The only thing about giant cabs is you’re kind of getting married to them, wont be as easy or quick to change things or add drivers.

SBA has great potential, the four 24 could qualify possibly, do you have room for back absorption?
 

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I don't know about modeling versus reality.

I do now that of the four UM-18s that came through my hands, none of them were close to published spec, like 50% high on Fs, and yes, I did break them in, and they changed more temporarily (and snapped back within about 5% of original after sitting a couple days) so...

I didn't get as far as getting some modeling clay or something that could stay easily in place, so I didn't get any moving mass or Vas figures, but after 64 hours of cumulative and continuous (not just watching a movie with bass once in awhile, big sweeps the whole time) high excursion break in.... This woofer was typical of the other 3, including the two that only had the break-in of my pushing on the spiders.

Does that look like an Fs of 19.5 Hz to you? Me either.
3077935


Regardless, if you do buy them, I would suggest actually measuring the drivers you've got before modeling a box for them, and maybe even testing them immediately after running them at high output for 15 minutes or so, so that you can compare the TS parameters with warm coils versus cold, and see how that affects the modeling.

the other thing to keep in mind is that modeling is just modeling. Peak to peak excursion is stated at over 2". I think that is mechanical range where things don't break. The technical X-max, which is the theoretical 'linear' range where distortion stays low, is listed at 22mm, that's 44mm peak to peak, or 1.6 inches of travel. I don't know if they're figuring that by the difference of the coil height versus the gap height, or where BL drops below 70%, but when I was breaking in the driver in free-air, the whole thing kept quiet in terms of noises that weren't the test tone (low audible distortion) to about 1 inch peak to peak. Beyond that, the extra noise makes a subwoofer useless for my application. But, to be fair, that's still pretty darn good, even if it's short of what the marketing hype would suggest.

For the cost of the driver, I don't think anybody is getting ripped off, particularly if they check to see if it's what they want within the 60 day 'no questions return' period, but I would say be ready to run with it to figure out the reality of the particular units you get before that period ends, or else you get what you get, and if you don't like it, that's too bad.

Now, all of that borderline trash talking put aside (and I will offer full disclosure, part of me is just butt-hurt about being lied to) the drivers seem to be able to be made to work reasonably well given the price, given tactfully applied EQ to smooth out the higher Qtc (in a sealed box) and extend the bass (that rolls off faster than modeled because of the higher Qtc, and having played with it, while I sure wouldn't claim that the upper bass is going to compete with pro drivers, having played with it a bit, in my experience the quality of what a lot of people call the 'mid-bass' region of the subwoofer seems to be not just related to the output of the subwoofer itself, but the splicing of the subwoofer with the 'main' speakers, which involves not just the slope, shape, and crossover point of the subwoofer, but the total end product of the main speakers, which includes the low-end roll off of the speakers itself. So, I do suspect that those who don't (or can't, because most AVRs don't give you much control other than perhaps frequency) address the crossover alignment on both sides of that splice are probably sacrificing a lot and getting less out of the UM-18 than it can provide.

But to your question, is it actually everything that the model predicts in a ports scenario as you've modeled? I suspect not, but I would defer to people who have actually built it based on the specs and modeling, and measured it outside.

But if you can get them for $300 each shipped, they might still be a great bargain if you want to move some air with relatively modest driver investment.
 

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Heck ya, four UM18’s going to 15hz and some ...... 8’s???? Well that should get you some pretty awesome SPL levels and should sound pretty clean. Four amps should do nicely, maybe a minidsp and/ or some dsp amps. Should only take you a month or two trying to figure out the best location for just the UM’s and then the 8’s (???) also. After that you get to sit down and make sure your xo from UM’s to 8’s (???) is satisfying. matching spl levels and room modes should only take a couple of days and then you may have to reconfigure your front boxes all over again, but by that time you should have your xo dialed in a little better. Then.... after a couple of months of some pretty good sound you’ll find out that everyone here has recommended a pro 21” (lavoce or NSW) instead of the lack luster (for midbass) UM setup (and a quite complicated setup too).
The cool part is that by the time you realize all this, you will have spent a crap load of time and energy into something that is only “okay”, oh... .

For the same money and less time, less amps, less setup time, less power consumption, less wires, less moving large boxes around you could have actually been enjoying your setup..... with.... get this... the same exact sound and “speed of the woofer”.

Save yourself, Just get four 21” and tune them to 15hz - 17hz and be done, or drop them in some Devs.
 

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Since you're still in the thinking stage, look into a BOSS:
Michael
 

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People are almost cultish with subwoofer recommendations.

My buddy and I compared his LMS 5400 in my room to my UM18-22 in the same 21” sealed box. (The LMS5400 is objectively one of the best 18" subwoofers ever made)
I have eight, he has two. We paid the same total amount for our drivers. Total of $2K. We bought our boxes from the same vendor/same box. (Of course I spent significantly more on boxes). At the end of the comparison after neither of us could “hear” a difference he said, ‘tell me why I paid this much more for my drivers again?’

The only difference of consequence we could measure/observe was that a single LMS5400 could handle a couple more dB from my Crown XLS-5000 amp. We could make both subs start to distort with the amp, the LMS just had a couple dB more before it cried uncle. However, when played as a whole, eight UM-18 certainly have more output and uniformity of coverage than two LMS-5400.

After that test, and other subwoofer tests I’ve participated, even a blind test, where keen enthusiasts (the kind of keen enthusiasts who will travel across the nation to a subwoofer get together) couldn’t tell the difference between a high quality ported, high quality horn, or high quality sealed sub in a blind test — well my conclusion is/was I’ve never wanted for a different driver these 6-7 years I’ve owned the UM18-22. They are an excellent choice, I am quite pleased with them.

My current frequency response with eight sealed Dayton Audio UM18-22 subwoofers (unsmoothed)


My affection/appreciation for the UM18-22 is not driven by lack of knowledge or experience. Here is a list of the subwoofers I’ve heard in
person. Post 2.

And here is one of the blind tests I’m referring to Archaea's Kansas City Blind Subwoofer Shootout 2012
 

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If SBA is a real option,
you'll def want to look into the superlative work and resources here

yes, I had the opportunity to visit Mike's system and it is truly a work of near perfection as you are liable to get.
 
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People are cultish with subwoofer recommendations.

My buddy and I compared a LMS 5400 in my room in a 21” sealed box to my UM18-22 in the same 21” sealed box. (The LMS5400 is one of the best subwoofers ever made)
I have eight, he has two. We paid the same total amount for our drivers. Total of $2K. We bought our boxes from the same vendor/same box. (Of course I spent significantly more on boxes). At the end of the comparison after neither of us could “hear” a difference he said, ‘tell me why I paid this much more for my drivers again?’

The only difference of consequence we could measure/observe was that a single LMS5400 could handle a couple more dB from my Crown XLS-5000 amp. We could make both subs start to distort with the amp, the LMS just had a couple dBmore before it cried uncle. However, when played as a whole, eight UM-18 certainly have more output and uniformity of coverage than two LMS-5400.

After that test, and other blind subwoofer tests I’ve participated where keen enthusiasts (the kind of keen enthusiasts who will travel across the nation to a subwoofer get together) couldn’t tell the difference between a high quality ported, high quality horn, or high quality sealed sub in a blind test — well my conclusion is/was I’ve never wanted for a different driver these 6-7 years I’ve owned the UM18-22. They are an excellent choice, I am quite pleased with them.

My eight UM18-22 omnimic capture. No smoothing.
subjectively, I think hitting the resonant frequencies of the chest tissue just right to give that bit of "punch" or "visceral" effect is what many people are subconsciously looking for.

These really big popular sub drivers are all generally great and easy to produce great sound.

A multi-sub setup with electronic multi-sub-optimization was the holy grail for my room.
 
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Small woofer fast bass is an old myth. Lots of very capable big drivers, motor force, design and inductance all play into good quality output and where it hits. The heavy cone, big motor, big coil, higher Le drivers (stereo integrity and the like) play lower, the lighter cone, low Le pro drivers are better at mid bass, as a generalization. Apparently the Harbottle 24 does it all from reading. I mean you could put four Harbottle 24 in less space sealed and it would destroy four 18s. Not same budget of course :) But the 24 in what is it 8 feet? Whole thing around 120lbs? The SI weighs 90 ish by itself? Anyway I digress.

The only thing about giant cabs is you’re kind of getting married to them, wont be as easy or quick to change things or add drivers.

SBA has great potential, the four 24 could qualify possibly, do you have room for back absorption?
In fact I would say the biggest subs make the most sense. You want the drivers barely moving to produce most of the desired frequencies at desired listening volumes. The bigger the drivers and the more of them you have, the less distortion overall that each is likely to be facing.

Most people are jacking up their sub volume for nulls or for lack of punch anyway. The worst is when you have a null in the punch region... argh.
 

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People are cultish with subwoofer recommendations.

My buddy and I compared a LMS 5400 in my room in a 21” sealed box to my UM18-22 in the same 21” sealed box. (The LMS5400 is one of the best subwoofers ever made)
I have eight, he has two. We paid the same total amount for our drivers. Total of $2K. We bought our boxes from the same vendor/same box. (Of course I spent significantly more on boxes). At the end of the comparison after neither of us could “hear” a difference he said, ‘tell me why I paid this much more for my drivers again?’

The only difference of consequence we could measure/observe was that a single LMS5400 could handle a couple more dB from my Crown XLS-5000 amp. We could make both subs start to distort with the amp, the LMS just had a couple dBmore before it cried uncle. However, when played as a whole, eight UM-18 certainly have more output and uniformity of coverage than two LMS-5400.

After that test, and other blind subwoofer tests I’ve participated where keen enthusiasts (the kind of keen enthusiasts who will travel across the nation to a subwoofer get together) couldn’t tell the difference between a high quality ported, high quality horn, or high quality sealed sub in a blind test — well my conclusion is/was I’ve never wanted for a different driver these 6-7 years I’ve owned the UM18-22. They are an excellent choice, I am quite pleased with them.

My current frequency response with eight sealed Dayton Audio UM18-22 subwoofers (unsmoothed)
I have been saying this over and over. I am not quite sure how people are comparing nowadays, but we have gone backwards it seems, lol.
 

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Most people are jacking up their sub volume for nulls or for lack of punch anyway. The worst is when you have a null in the punch region... argh.
I have been saying this over and over. I am not quite sure how people are comparing nowadays, but we have gone backwards it seems, lol.
Excellent points both...and I am just amazed that we don't hear folks ring in with the gorilla in the room to which @blazar refers...and that's the science of small room acoustics.

@JayMan72...the best advice anyone here can give you is to do your homework on small room LF acoustics in your planning. You have not mentioned dimensions and volume of your planned theater room. Those and location of subs relative to the seating area are crucial to LF performance. In an acoustics class I attended with Anthony Grimani at THX it was demonstrated how a giant sub with a monstrous 18Hz spl test tone could be rendered silent at a common location for home theater seating (at the 1st node harmonic). Step three feet forward or backwards from the spot, and the spl was deafening. Step back to the null spot...and silence. It's quite amazing.

I recently completed a bass upgrade using two MiniMartys (UM-18) and two sealed MBMs (PA-460). Fortunately, the locations of the four cabinets are acoustically friendly...which is essential. This approach in my large, huge volume room renders several things well: First, using the DSP in the Behringer amps along with careful/precise use of the MEQ Editor App and RTA verification, integration between the MiniMartys, MBMs, and mains is seamlessly smooth. Second, this enables each sub to perform predominantly within the range in which it's performance is nominal. This approach provides a ton of head room so that the amps and drivers are never strained. Finally, it sounds fabulous...but is content-driven. If low content is in the program, you will hear it. If it is not, you won't, and there will be no coloration of what you do hear.

Another great benefit from this approach is great dynamics IF the mix provides it...whether music or movies. A good example is the recent new Atmos mixes of the new UHD issue of the LOTR trilogy. The three movies differ with regards to bass. The FOTR not only has deep bass, it has the dynamics in spades. The following two movies have somewhat less low bass than previous BD issues, and perhaps worse, they have less dynamics. They're plenty loud, including the LF content but these never have the impact we expect; the mix is somewhat compressed so that it is kind of loud all time in big action sequences rather than giving specific events the impact they should have. The siege of Helm's Deep has numerous examples in TTT, as does the final battle in ROTK. My point is that it is content-dependent, but a good LF design in your room will be faithful, transparent, and revealing. A particularly fun movie with my bass upgrade is MI Fallout. The mix puts the musical score pretty forward, and it is very sonically impressive with percussion, low strings, and synthesizer for lowest notes. The LF system is very quick and responds to the dynamics very well. The CD retains all this fun if you just want the music. Just listening to the CD, there are low amplitude tracks/passages that also have deep bass that are very impressive. We are so used to VLF being loud, but even when not, they impress!

The best homework source available on LF in home theater size rooms IMHO is the Harman White Papers by Todd Welti. There is also very good reading on the GSG Audio site.

Cheers.
 

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That is bad news about the UHD of the two towers and return of the king. I want you to give the beginning scene of mission impossible rogue nation a spin from the beginning until he escapes the airplane. How does that sound to you?
 

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@MKtheater...I'll be happy to do so. I also like that movie a lot, but haven't checked it in a while. I'm not sure there's a ton of very low stuff in that scene...is there? What in general in that scene do you want me to listen for? I'll respond via PM so as not to hijack.

Take a listen in the Helm's Deep explosive breach sequence in your former BD version. That giant chunk of wall hitting the ground in a wide shot was a real crowd pleaser. It's ho-hum now by comparison.
 

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I will, I usually watch the Balrog scene from Fellowship. I only have the BR extended version. I just wanted you to notice the dynamics in comparison. When the plane starts up the propellers hit pretty hard, cool effect and there is low energy from plane throughout.
 
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