I'm looking into building either one or two 18" subs for home theater application, but will likely also serve double duty as subs for inside my Sprinter van on occasion.
I've never had any sub in home or car more than 12", and the goal is to get some really deep bass that can be "felt", yet still maintain a fair level of SQL.
I'd like the boxes to be not obnoxiously large or heavy, so probably somewhere between 4-8 cu.ft. for each driver.
So, for these drivers and probably any other inexpensive 18" driver (or larger) I am looking at sealed boxes.
Crown XLS 2502 is available to power the HT, and SoundQubed Q1-1200.2 available as power for van application.
I saw UM 18 for $288 recently which seemed like a great deal, but then stumbled upon the SI HT-18's in forum discussions and they seem very promising for $200.
Does anybody have direct experience with both of these in sealed box applications in the size range I am looking to build? It would be great to have an "apples-to-apples" comparison is anybody had experimented with each of these in identical boxes with identical power. I know this kind of thing can be modeled in software, but I am more interested in getting some feedback from an actual person experiencing them first-hand.
For the price of 2 UM, I could get 3 SI, but since I wouldn't use 3 drivers I guess the question becomes are the UM worth $600 vs $400 for the SI's?
Also, if it turned out that only one would up in my house and only one in the van, then would the SI handle enough power and provide similar output as the UM?
Thanks
I've never had any sub in home or car more than 12", and the goal is to get some really deep bass that can be "felt", yet still maintain a fair level of SQL.
I'd like the boxes to be not obnoxiously large or heavy, so probably somewhere between 4-8 cu.ft. for each driver.
So, for these drivers and probably any other inexpensive 18" driver (or larger) I am looking at sealed boxes.
Crown XLS 2502 is available to power the HT, and SoundQubed Q1-1200.2 available as power for van application.
I saw UM 18 for $288 recently which seemed like a great deal, but then stumbled upon the SI HT-18's in forum discussions and they seem very promising for $200.
Does anybody have direct experience with both of these in sealed box applications in the size range I am looking to build? It would be great to have an "apples-to-apples" comparison is anybody had experimented with each of these in identical boxes with identical power. I know this kind of thing can be modeled in software, but I am more interested in getting some feedback from an actual person experiencing them first-hand.
For the price of 2 UM, I could get 3 SI, but since I wouldn't use 3 drivers I guess the question becomes are the UM worth $600 vs $400 for the SI's?
Also, if it turned out that only one would up in my house and only one in the van, then would the SI handle enough power and provide similar output as the UM?
Thanks
Hmm, FWIW/IME, etc., as a general ROT, high Vas drivers such as the SI and mobile audio are a poor match.
Yeah, I seem to recall a few people saying the SI needed bigger boxes to perform well. Vas of UM is 5.11cuft (~145 liters) vs 220 liters for the SI.
So, I know a lot goes into how a driver performs, but sounds like UM-18 likely puts out more and deeper bass in something like 6cuft.
Not sure if it makes a difference, but how about the cones and baskets? UM seems to have better overall construction materials. Is that of any concern for the SI? Seems to me that each of these drivers gives quite a bit of bang for your buck, maybe the UM you pay a bit more to get a bit more. But on a relative basis they are both excellent for their price.
So, I know a lot goes into how a driver performs, but sounds like UM-18 likely puts out more and deeper bass in something like 6cuft.
Not sure if it makes a difference, but how about the cones and baskets? UM seems to have better overall construction materials. Is that of any concern for the SI? Seems to me that each of these drivers gives quite a bit of bang for your buck, maybe the UM you pay a bit more to get a bit more. But on a relative basis they are both excellent for their price.
Before buying, see this PETT discussion about OEM changes to the UM18. I linked to post 21, but you'll want to read to the end.
Yeeh Ha! Big is as big does! 😉
Rev. T/S max flat:
891.91 L/31.4975 ft^3
15.5 Hz Fb
12"/30.48 cm dia. x 30.32"/77 cm vent
So some form of OB, sealed or (ML) TL required.
Rev. T/S max flat:
891.91 L/31.4975 ft^3
15.5 Hz Fb
12"/30.48 cm dia. x 30.32"/77 cm vent
So some form of OB, sealed or (ML) TL required.
This is really interesting for a few reasons.
First, when I was looking at how to input data for new drivers into WinIsd, I stumbled across a video from 2016 that used the UM 18 as the example and noticed it had different specs back then than what is currently listed for the driver.
Second, because I have started contemplating using a ported box instead of sealed. Looking around forums, it seemed that neither of these is really going to be happy in a smaller ported enclosure...but the SI supposedly wants a much bigger box...like at least 12-20 cuft whereas the UM maybe could get away with 8-10 cuft.
In light of this new information with regards to a ported enclosure (or sealed for that matter) are you guys saying that as of right now in 2023 that the specs on the SI and the UM are getting closer to each other (with regards to box size and response) and therefore the UM does not have nearly the advantage it used to have over the SI with regards to enclosures? In other words, if I don't have a ton of watts to throw at either of these and they will both want relatively large enclosures, then the only advantage the UM now has is a much sexier looking cone.
Also, I just take issue with this statement from PE:
"It was discovered that changes were made to our beloved Ulitmax subwoofers and after discussing this issue with our supplier, it is unfortunate to learn that these changes are permanent."
Let's be honest here... nothing like this is "permanent". The changes in materials, procedures, tooling etc. were made for a reason and the reason is probably cost. And that's fine, but just admit that you could remedy the "permanent change" by switching suppliers and/or applying a higher cost to the driver in order to account for inflation of the last few years.
First, when I was looking at how to input data for new drivers into WinIsd, I stumbled across a video from 2016 that used the UM 18 as the example and noticed it had different specs back then than what is currently listed for the driver.
Second, because I have started contemplating using a ported box instead of sealed. Looking around forums, it seemed that neither of these is really going to be happy in a smaller ported enclosure...but the SI supposedly wants a much bigger box...like at least 12-20 cuft whereas the UM maybe could get away with 8-10 cuft.
In light of this new information with regards to a ported enclosure (or sealed for that matter) are you guys saying that as of right now in 2023 that the specs on the SI and the UM are getting closer to each other (with regards to box size and response) and therefore the UM does not have nearly the advantage it used to have over the SI with regards to enclosures? In other words, if I don't have a ton of watts to throw at either of these and they will both want relatively large enclosures, then the only advantage the UM now has is a much sexier looking cone.
Also, I just take issue with this statement from PE:
"It was discovered that changes were made to our beloved Ulitmax subwoofers and after discussing this issue with our supplier, it is unfortunate to learn that these changes are permanent."
Let's be honest here... nothing like this is "permanent". The changes in materials, procedures, tooling etc. were made for a reason and the reason is probably cost. And that's fine, but just admit that you could remedy the "permanent change" by switching suppliers and/or applying a higher cost to the driver in order to account for inflation of the last few years.
Last edited:
Hmm, I need to double check my sims, but the SI appears to 'blow the doors off' the UM in a major way..........
Could you explain the graph a little? I'm not sure I understand it and why you are using 580w for the UM and 750w for the SI.
Also, I can't tell if you are being sarcastic or genuine about the SI blowing the doors off the UM.
With the UM specs updated (and perhaps even worse than what PE is now listing...like Fs, Qts and Vas measuring way higher by some people), I guess what I'm really asking is the same as post #6:
In sealed boxes of the same size, say 6cuft, or ported boxes of same size and tuning, say 10cuft tuned to 20-22hz, and fed a max of 750w will these two drivers perform in a very similar way? I love the look of the UM cone and frame, but if the sound is no better than the SI and I don't really need higher power handling capabilities then I'm not sure if the UM would make sense. It really stinks, though...I guess should have bought one 10yrs ago when the old specs applied.
Also, I can't tell if you are being sarcastic or genuine about the SI blowing the doors off the UM.
With the UM specs updated (and perhaps even worse than what PE is now listing...like Fs, Qts and Vas measuring way higher by some people), I guess what I'm really asking is the same as post #6:
In sealed boxes of the same size, say 6cuft, or ported boxes of same size and tuning, say 10cuft tuned to 20-22hz, and fed a max of 750w will these two drivers perform in a very similar way? I love the look of the UM cone and frame, but if the sound is no better than the SI and I don't really need higher power handling capabilities then I'm not sure if the UM would make sense. It really stinks, though...I guess should have bought one 10yrs ago when the old specs applied.
Just considering quick sims of 6-8ft^3 closed boxes, I believe you'll be limited by the amp, approximately 3dB below Xmax around 20Hz. The SI might have a 1dB advantage, but I'd hesitate to call it a clear win considering parameter differences vs. sim vs. real life. Even in these "small" boxes, they're both pretty serious subs.
Consider that running to ~70% of Xmax will keep distortion low. Sure, you're giving up a few dB of potential output, but is that a problem when you want high-quality bass? If you're really that worried about the extra dB, go for 2x of the cheaper SIs. Assuming you have a spare amp channel in your XLS, it's not that much more money than a single UM18.
Consider that running to ~70% of Xmax will keep distortion low. Sure, you're giving up a few dB of potential output, but is that a problem when you want high-quality bass? If you're really that worried about the extra dB, go for 2x of the cheaper SIs. Assuming you have a spare amp channel in your XLS, it's not that much more money than a single UM18.
The red part of the trace is where the UM is exceeding its Xmax @ 580 W in a ~892 L/15.5 Hz Fb T/S max flat vented alignment, ergo down low the UM is limited to a useful 580 W Vs the SI's 750 W rating in a 270 L/16 Hz EBS vented alignment except over a very narrow 'peak' in the 10-20 Hz BW, so really doesn't count in the 'scheme of things'.
As I noted, I posted it before realizing it was an 'apples n' oranges' (invalid) comparison due to differing pi loading of each (half space Vs 1/4 space) and thought I had deleted it, so in retrospect guess I should have had a mod delete it (reported it just now to save any future confusion: edit, at this late date they chose to leave it as is).
In the above vented alignments; at > ~580 W the UM will exceed Xmax below ~35 Hz and by ~17.5 Hz will be 4x over and by ~8.75 Hz will be 8x over, so somewhere along this BW it will bottom out and assuming it's like drivers I've seen self destruct long ago it will 'grenade'/burn up/spit out pieces of voice coil, maybe set fire, hurt someone and/or property, etc.; the SI OTOH will produce significantly less peak SPL below ~22 Hz @ 750 W.
So in ~short, none of this was meant to answer your specific questions, just me posting a quick comparison I did for myself to 'highlight' just how different/dramatically these new specs altered which to choose, which at a glance the UM is still preferred for when wanting < ~ 22 Hz output at any useful SPL.
Last edited:
Yeah, with the UM needing a ~3.3x larger box for a ~performance comparison makes it a poor choice overall unless really wanting its < ~22 Hz BW advantage.
Hammer Sandwich -- if I'm interpreting you correctly, these two are now pretty close in terms of performance in similar sized sealed enclosures especially at the watts that I can throw at them. So, two SI 18 at $400 is a better deal than 1 UM at $290 or even two UM at $580 on a cost-to-performance measure.
GM -- to simplify things, it sounds like you are saying the new specs of the UM make for a substantially larger box requirement as opposed to the old specs. So unless digging below 22hz, just save some money and get the SI drivers. The SI want large boxes, but now the UM's also want equally large boxes.
I have Winisd but am not sure if I am using it correctly. I will try to model both in there for ported boxes, however would somebody better at this stuff be willing to throw some relevant graphs of these two in apples-to-apples boxes of 10cuft tuned to about 20-22hz?
GM -- to simplify things, it sounds like you are saying the new specs of the UM make for a substantially larger box requirement as opposed to the old specs. So unless digging below 22hz, just save some money and get the SI drivers. The SI want large boxes, but now the UM's also want equally large boxes.
I have Winisd but am not sure if I am using it correctly. I will try to model both in there for ported boxes, however would somebody better at this stuff be willing to throw some relevant graphs of these two in apples-to-apples boxes of 10cuft tuned to about 20-22hz?
I haven't used WinISD since 2008? once Hornresp was expanded enough to suit me; regardless, UM @ rated max 1000 W (shadow/faint/gray) - SI @ rated max 750 W in 10 ft^3 net/22 Hz Fb comparison (both sims are with 'Le' distortion enabled):
Attachments
That's how it looks to me in a ~200L closed box. I get where @GM is coming from, but I wouldn't want to port such high-Qts drivers. Plus, the lumber for a 20-30ft^3 box would cost as much as a 2nd HT-18!
Me neither WRT basic T/S alignments, I just use(d) them to highlight any differences, but in mass loaded/vented TLs it's another 'story' altogether. 😉
So if ported is out and they perform similarly in sealed, then may not make sense to do the UM over the SI for some sealed enclosures.
Plus, looks like the sale ended on the UM, so they are back to $340 each instead of $290 each. For a mere $60 more than a single UM one can get two SI's, so even with the cost of another full sheet of MDF for an additional cabinet, it seems like a "no brainer" for my wattage, space and dollar budget.
I'm in no particular hurry for this project, so I've also been looking on FB Marketplace to see if anything pops up. Found some used Soundqubed hdx4 18 in my area for sale, guy is asking $400 each. Any opinions on these? I know they are typically used in automotive applications, but the specs look favorable. It seems they'd be capable of plenty of SPL, but not sure about the SQL.
https://soundqubed.com/18--hdx4-series-subwoofers/
Plus, looks like the sale ended on the UM, so they are back to $340 each instead of $290 each. For a mere $60 more than a single UM one can get two SI's, so even with the cost of another full sheet of MDF for an additional cabinet, it seems like a "no brainer" for my wattage, space and dollar budget.
I'm in no particular hurry for this project, so I've also been looking on FB Marketplace to see if anything pops up. Found some used Soundqubed hdx4 18 in my area for sale, guy is asking $400 each. Any opinions on these? I know they are typically used in automotive applications, but the specs look favorable. It seems they'd be capable of plenty of SPL, but not sure about the SQL.
https://soundqubed.com/18--hdx4-series-subwoofers/
SQL in a limited BW sub is almost an oxymoron since the room dominates and driver Qt, i.e. Fhm gain BW, inductance (Le) relative to XO point/slope sets 'SQL'.
So, GM...let's just pretend I have no idea what all the abbreviations in your previous post mean (BW, Fhm, etc)
I read the Adire link and they seem to be saying low inductance creates a better transient response and therefore probably better "SQL"
I read the Adire link and they seem to be saying low inductance creates a better transient response and therefore probably better "SQL"
