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Dayton Audio Ultimax UM18-22 in a 24 cuft enclosure: what design?

What design?  

4 members have voted

  1. 1. What design would fit the best with this driver and (fixed) enclosure volume?

    • Single driver, sealed
      0
    • Doubledrivers, sealed
      1
    • Triple drivers, sealed
      0
    • Single driver, ported
      0
    • Double drivers, ported
      3
    • Single driver with Passive Radiators
      0


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24 minutes ago, Infrasonic said:

Actually, the whole system is quite underpowered but that's okay because I make up a lot with the very high sensitivity. Having a subbass system that is >100dB sensitive means cool running amps too. :D

I didn't really calculate the amount of power /sub, as I read your AVS thread after posting this! But still lot of (absolute) power, maybe not relatively, but hey with a +db sensitivity you're good to go ;) just put the finishing touches on my PA sub, so gonna be testing it tomorrow! It doesn't dig deep, but it does have a 105db sensitivity ö It's a shame my exams are getting closer and I literally don't have any time to listen to it :( 

24 minutes ago, Infrasonic said:

There are seven subbass enclosures in my HT room. Six identical dual-opposed sealed enclosures. Four up front, two in rear. Each approx. 8cuft each. Four up front house the eight Stereo Integrity HT18's.

You might not believe me, but I've read your build few times now, and Ive never noticed those 18"'ers in the front lol, they are so black! Are those all 15"ers for your LCR? So 12x 15" and 8x 18"s, in the front? :P I think I love you. qIElAdr.jpg

24 minutes ago, Infrasonic said:

The two in the rear house four Sound Splinter RLp18's. Then the riser with the last two SS RLp18's.

What was the purpose of the 2 rear subs? Just extra output? Or also a kind of NF experience? 

24 minutes ago, Infrasonic said:

The riser is very simple. Top and bottom are just some 5/8" or 3/4" plywood. I don't remember exactly. *laughs* Not even really high end stuff either but solid. The walls are made from 2x8's cut to the length I wanted for this size.

There is a single 2x4 in the middle (running between the two drivers). The extra baffle pieces were added to accommodate the depth of the RLp driver.

How much place did you leave behind the drivers? Or, how high is the riser from the floor up to the baffle? Doesn't seem to high!

24 minutes ago, Infrasonic said:

The riser is the only enclosure I've ever built that I didn't really "design". Just thought it up in my head and then simulated to "make sure". Certainly couldn't simulate how it was going to feel. Had to build it to really know for sure.

I'm guessing, if I want to pull this of I'll have to take the actual in room size of the riser as a priority, and the "ideal" enclosure as a second. 

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40 minutes ago, Droogne said:

I didn't really calculate the amount of power /sub, as I read your AVS thread after posting this! But still lot of (absolute) power, maybe not relatively, but hey with a +db sensitivity you're good to go ;) just put the finishing touches on my PA sub, so gonna be testing it tomorrow! It doesn't dig deep, but it does have a 105db sensitivity ö It's a shame my exams are getting closer and I literally don't have any time to listen to it :( 

You will. Exams end eventually. ;)

40 minutes ago, Droogne said:

You might not believe me, but I've read your build few times now, and Ive never noticed those 18"'ers in the front lol, they are so black! Are those all 15"ers for your LCR? So 12x 15" and 8x 18"s, in the front? :P I think I love you.

Aww. :wub:

Yep. Lots of surface area. Proper midbass reproduction. :D

40 minutes ago, Droogne said:

What was the purpose of the 2 rear subs? Just extra output? Or also a kind of NF experience? 

First-most, they are there for front/rear sub blending. Used for smoothing the response of the whole. At the time, there was no intention of a sub riser so in a way I thought they would be "nearfield" but I chose to take that road after every one else started putting their subs AT their seat. Like, 1" away. So I can't really call them nearfield these days cuz they are about 3-4ft away. The subriser is the nearfield sub.... now.

40 minutes ago, Droogne said:

How much place did you leave behind the drivers? Or, how high is the riser from the floor up to the baffle? Doesn't seem to high!

It's not. Just a step up.

Idk... about an inch or so behind the motor. Plenty of room around the drivers though.

40 minutes ago, Droogne said:

I'm guessing, if I want to pull this of I'll have to take the actual in room size of the riser as a priority, and the "ideal" enclosure as a second. 

No. Not necessarily. You have the opportunity to actually choose your drivers. I had two on hand and made it work. My riser both fits into the room and is ideally sized.

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3 minutes ago, Infrasonic said:

You will. Exams end eventually. ;)

Thats a fact, after those are done I have a few weeks/months I can focus 100% on the platform. 

3 minutes ago, Infrasonic said:

Aww. :wub:

Yep. Lots of surface area. Proper midbass reproduction. :D

I'm having a few pairs (2 or maybe even 3) of LaScalas build, should give me that awesome midbass! Depends on how the future goes, but might even use a stack of those/ speaker. First my K-402 h

3 minutes ago, Infrasonic said:

It's not. Just a step up.

Idk... about an inch or so behind the motor. Plenty of room around the drivers though.

No. Not necessarily. You have the opportunity to actually choose your drivers. I had two on hand and made it work. My riser both fits into the room and is ideally sized.

If I use an inch, instead of 2, and place the woofers on top + maybe even get another couch/modify the one I have now (so I would have space between the ground/riser floor and the actual seatings) I might get away with a riser that only rises the couch by 2/3 foot(or less) when using an 18". Should be a lot more easy to place/convince the roommate off. It would also be ideal to use as a riser for a second couch when I want to convert the living into a full blown home-theatre for mass viewings. 

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On 14-12-2017 at 7:43 PM, Infrasonic said:

You will. Exams end eventually. ;)

You know, I have a 1000 projects going through my mind that I want to do. I just build my first flat pack, which gives me a good idea of how to get into building one myself. It was not a particularly complex one, but it was a horn loaded sub though. Which mean lots of corners, which had to be airtight. Made some mistakes, but it was a good experience as I now know how to fix them ;) Pretty confident I can build any riser I want. Have also found a seller for my pair of Chorus II (Klipsch) for a crazy sum, which gives me the budget to upgrade the active crossover of my LaScalas (to a Xilica). More importantly, it might lift up the need to go for a cheaper sub than the UM18-22 (which is a great sub for the sealed riser, but also seems immensely good in a ported enclosure. By my calculations it could be tuned to 12hz in a 1000L enclosure which is ofcourse to big, but it could still go down to 15hz in a "reasonable" 494L).

That way I could build both the ported and sealed and see how I like them, if I like both I can order another one. Or maybe another 3 ;) 

 

Just took some  measurements of my couch, and sad to say.. my main couch exists out of several different parts and doesn't really invite baffles that protrude into the couch. I could manage a 12" into the main seating place (which has a feet/leg extension thingy, not sure how to call it in English which makes it extremly dificult to fit something in), and a 15" into the "second" place. Those 2 places are the only ones that matter). I do however have found out that one of the side couches, which I could easily move into the sweet spot, could be what I need. I could stuff a box under it without having to rise it by more than 6cm. I would get a 125L enclosure, which is not very big though. It might just work.. 

 

It raises a question however: is it possible to let the sub protrude into the couch, with almost no place on each side? Like stuffing a 50cmx50cm enclosure into a 51cm x 58cm opening into my couch. The air moved by the sub would have almost nowhere to go, which kinda seems like a bad idea (although it can leave through the small 7 and 1cm cracks on the side + through the seating which is just a cushion). I'm only asking because it would  be the only way to have an 18" sub build into one of my couches.

EDIT: @Infrasonic , I think I overexplained myself a bit. I'm known to go one ramblings about everything, but when done in English about this kind of stuff I'm not beginning to guess how hard it is to understand what I'm actually trying to say. I'm over complicating things haha! Things are also changing all the time, so my mind is all over the place, trying things out and looking for ways to improve. Buuuut, maybe something to add to my big chunk text above here? 

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@SME Just found this sweet deal on a pretty cheap 18" sub. Would this be something good? (for sealed or ported sub 20hz sub @ moderate levers. Maybe even the riser.)

http://www.caradio.nl/index.php?page=producten_bekijken/detail.php&product_nr=4945&hoofdgroep=7&subgroep=31

EDIT: just been looking at the Qtc values, and it seems this one is not really suited for a sealed (1000L for  0,8 Qtc?? 300 for 1). This made me run the Qtc values for all the subs I've been looking at, and it seems that if I want to build small sealed enclosures to slide under the couch, then the Ultimax would get there with the smallest enclosure (and same Qtc). Makes me wonder: Infrasound recommended a Qtc between 0,57-0,8, and I'v been reading through your extensive voltage/impedance/sensitivity/Qtc explanation, but I'm not much wiser. It's very complex stuff ;) I really want to understand it though, just don't got the time to do the correct learning for now. If you take amp out of the equation, what would you recommend as Qtc for my very low end sealed sub (so LFE effects only)? I doubt I'll be pushing it to it's limits dB wise, although I might push it lower with the EQ. 

 

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Looks like a pro-style sub, designed mostly for mid-bass, and probably not a very good one at that.  The Xmax is claimed to be 25mm.  Is that one-way?  Cloth surrounds don't typically offer much excursion.  The motor is very weak.  It's claim to efficiency is made possible only by the tiny MMS of 96g.  It's efficiency at the lowest frequencies will actually be very poor.  That driver is kind of the opposite of what you want for the lowest freqs.

If you use EQ, the pros and cons of different Qtc depend on the efficiency vs. frequency shape you want and what the amp can do.  Sorry, there's no getting around that.  @Infrasonic's recommendation for Qtc is fairly reasonable.  You don't want much more than 0.7, IMO or else you will have poor efficiency and poor overall performance below the sealed system resonance frequency (Fb).  A lot depends on the Fb too.  A lower Fb is more important if Qtc is higher.  Drivers that work well at low frequencies typically have medium to strong motors (BL^2/Re) in addition to lots of Xmax.  Some have more mass than others, which basically trades lower Fb for higher Qts.  That trade is of minor importance for the lowest frequencies, but if you don't plan to run it very high, a bit more mass is probably a good overall. 

Note that the medium-to-high motor strength usually comes with a higher cost.  There is no free lunch.  Even a good pro driver usually has high motor strength, albeit with less mass and often stiffer suspension to improve efficiency and performance at mid bass frequencies.  The above driver is just cheap and probably only suited to covering a very narrow range of mid-bass frequencies.

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1 hour ago, SME said:

Looks like a pro-style sub, designed mostly for mid-bass, and probably not a very good one at that.  The Xmax is claimed to be 25mm.  Is that one-way?  Cloth surrounds don't typically offer much excursion.  The motor is very weak.  It's claim to efficiency is made possible only by the tiny MMS of 96g.  It's efficiency at the lowest frequencies will actually be very poor.  That driver is kind of the opposite of what you want for the lowest freqs.

Sorry to suggest it actually.. It looked cheap, and from what I know about specs it did indeed look that way too. That xmax also seemed to be blow out of proportion, not something I have ever seen on a pro sub. Was just hoping I might have found the european Stereo Integrity budget wise.  

1 hour ago, SME said:

If you use EQ, the pros and cons of different Qtc depend on the efficiency vs. frequency shape you want and what the amp can do.  Sorry, there's no getting around that.  @Infrasonic's recommendation for Qtc is fairly reasonable.  You don't want much more than 0.7, IMO or else you will have poor efficiency and poor overall performance below the sealed system resonance frequency (Fb). 

Aight, I'll try to keep it at 0,7. Again, only reasonable volume in the UM18-22 (280 for 0,7). I was using this formula to calculate, correct one? 

Find alpha: X = (0.70 / Qts)^2 - 1

Then calculate enclosure volume: Vb = Vas / X

 

I also found another 18" sub (B-stock model) with decent specs (25xmax) from a good brand: the B2 Audio IS18X. So the 18" version of one of the 15"ers I posted earlier. I think it's the closest 18" competition I have found (at this price point). 

It does have a pretty high Qts so I dont think I'm able to even reach a Qtc 0,7 right? Even a Qtc 0,8 would require a huge enclosure (856L)(280L for a 0,9 value). Is that what defines if it fits a sealed enclosure or not? 

1 hour ago, SME said:

A lot depends on the Fb too.  A lower Fb is more important if Qtc is higher.  Drivers that work well at low frequencies typically have medium to strong motors (BL^2/Re) in addition to lots of Xmax. 

How would you define "medium to strong"? Um1822 would have: 129 (Re = 4,4 and BL = 23,8) and the B2 Audio 177 (Re: 0,95 and BL =13).

1 hour ago, SME said:

Some have more mass than others, which basically trades lower Fb for higher Qts.  That trade is of minor importance for the lowest frequencies, but if you don't plan to run it very high, a bit more mass is probably a good overall. 

Note that the medium-to-high motor strength usually comes with a higher cost.  There is no free lunch.  Even a good pro driver usually has high motor strength, albeit with less mass and often stiffer suspension to improve efficiency and performance at mid bass frequencies.  The above driver is just cheap and probably only suited to covering a very narrow range of mid-bass frequencies.

 

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How much can you find the Alpine SWS-15 for? They go for just over $120 here. It's not a glamorous 30mm xmax sub with a jillion watts power handling, or 100dB sensitivity, but it is very well engineered, backed by a huge company and the specs are legitimate. It's a killer driver for the money. You can often get 2 or 3 of them for the price of a single good 18". The SWR-1522D or 1542D are also good and a bit beefier with a useful 20-25mm 1 way excursion, but a bit more expensive.

These should be available where you are but I'm not sure what the cost is where you are. They are a very reasonable here in NA.

https://www.ebay.de/itm/Pair-New-Alpine-SWR-1522D-15-4000-Watt-DVC-2-Ohm-Car-Subwoofers-Subs-SWR1522D/302565646107?epid=69759827&hash=item4672515f1b:g:-WEAAOSw401aMvsW

https://www.ebay.de/itm/Alpine-Type-S-SWS-15D4-15-1500-Watt-Dual-4-Ohm-Car-Audio-Subwoofer-Sub-SWS15D4/351607121407?epid=1700178220&hash=item51dd6ae5ff:g:u5QAAOSwgQ9Vib0U

Just a couple of other options to consider. These drivers are vetted and known to be good quality. Sadly to say unless you are familiar with a company and it's products you may be rolling the dice buying an unknown driver based on specs alone. Some of them are notoriously inflated to sell more product. Xmax, sensitivity and power handling are the worst.

 

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2 hours ago, Ricci said:

How much can you find the Alpine SWS-15 for? They go for just over $120 here. It's not a glamorous 30mm xmax sub with a jillion watts power handling, or 100dB sensitivity, but it is very well engineered, backed by a huge company and the specs are legitimate. It's a killer driver for the money. You can often get 2 or 3 of them for the price of a single good 18". The SWR-1522D or 1542D are also good and a bit beefier with a useful 20-25mm 1 way excursion, but a bit more expensive.

These should be available where you are but I'm not sure what the cost is where you are. They are a very reasonable here in NA.

https://www.ebay.de/itm/Pair-New-Alpine-SWR-1522D-15-4000-Watt-DVC-2-Ohm-Car-Subwoofers-Subs-SWR1522D/302565646107?epid=69759827&hash=item4672515f1b:g:-WEAAOSw401aMvsW

https://www.ebay.de/itm/Alpine-Type-S-SWS-15D4-15-1500-Watt-Dual-4-Ohm-Car-Audio-Subwoofer-Sub-SWS15D4/351607121407?epid=1700178220&hash=item51dd6ae5ff:g:u5QAAOSwgQ9Vib0U

Just a couple of other options to consider. These drivers are vetted and known to be good quality. Sadly to say unless you are familiar with a company and it's products you may be rolling the dice buying an unknown driver based on specs alone. Some of them are notoriously inflated to sell more product. Xmax, sensitivity and power handling are the worst.

 

Thanks for the suggestion! I once looked at the alpine woofers, but they didnt have any 18"ers, which is why I passed on them. I'm know revisiting some of the 15"ers so it's good to take these back into consideration. It seems the SWR1522/42D cost a lot (same as the Ultimax 18", and definitely more than the Ultimax 15"), and I cant seem the find the specs.. have mailed them, so who knows what that will turn up. 

 

It's true though.. I cant find anything about those other brands.. which is why I'm so hesitant. I only have to pick one in around a month, so who knows what will turn up ;) In the end, although I want to have it set up as good as possible, if I pick a 15"er it will ultimately end up in my bedroom. So it's not that bad if it turns out not so great. 

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@SME @Ricci just found a great B-stock/demomodel pair for 700 (instead of 1000 each). Another B2 Audio model (and they look amazing!). What would you say about these specs? Considering they are not inflated? 

image.png.1f062a0bac3630a1244e629c6b7f58e2.pngimage.png.188ca6c6f3211c143824506f0ad1e7ac.png

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