AVS Forum banner

801 - 820 of 928 Posts

·
Registered
Joined
·
1,518 Posts
Think people on here tend to focus on the "high xmax" drivers and ignore most of the other tested systems but it is interesting to look at other systems. There's actually a few more ported 18 tests there.

Happy reading! :)
 

·
Registered
Joined
·
19,256 Posts
Discussion Starter #806
It is to me as I use many and the distortion numbers are much less in room with multiples. It all has to do with design goals and room. If I changed all my drivers to LMS5400's I would gain more headroom and less inaudible distortion so I would never use it anyways. If I needed less drivers or my room was enormous I would design differently.
 

·
Registered
Joined
·
992 Posts
It is to me as I use many and the distortion numbers are much less in room with multiples. It all has to do with design goals and room. If I changed all my drivers to LMS5400's I would gain more headroom and less inaudible distortion so I would never use it anyways. If I needed less drivers or my room was enormous I would design differently.
You are one of the few who still want single digit extension though aren't you?
Not saying it's bad as I am the same or will be the same.
 

·
Registered
Joined
·
11,769 Posts
We did it at gorrilla83's to a degree --- not ABX - but rather AB, and with about 15 to 20 people --- but we used an 18Hz HPF. This was with three Seaton Submersives in a room with a TON of room gain.

The results were very underwhelming --- and while a difference could barely be told -- and I do mean barely --- most did guess right -- including myself --- However --- beyond a shadow of a doubt -- I would easily have picked the raw output of three ported caps over the extra extension below 18Hz on the three submersives as my favorite. It was so minimal it was hard to tell by nearly all accounts present. --- in which demo had the HPF or not. It didn't make big waves at the forum --- and when we brought it up we were told that the three Submersives weren't the right sub to test with. Blah --- Gorilla83's room gain is so ridiculous a 15" sealed sub in his room has more low end gain than a pair of 18" sealed in my previous, and current room.

IMO --- the only way you could tell with an HPF at 10hz --- is if the demo area was on a wooden suspended floor - or you were listening with an EXTREME house curve, AND you weren't listening with real world material at real world volumes. That's been my experience after testing with 14hz, 16hz, and 18hz HPFs in multiple different rooms on very capable systems including Carps (8 - 18"s), Desertdomes (8 - 15"s suspended floor), popalocks (16 - 18"s), and Gorilla83's. (six 15"s at the time). Even desertdome with his 8, 15" subs mounted DIRECTLY to the wooden suspended floor (hanging into the crawl space) has determined below 14hz doesn't matter to him. I still need to experience MK's room - but I've not been convinced otherwise yet - and I'm having a hard time believing that'll change after exeperiencing popalock's room.

Another time you might be able to notice less than 10hz would be if the sub is firing directly into your back - nearfield.
 

·
Banned
Joined
·
29,681 Posts
We did it at gorrilla83's to a degree --- but we used an 18Hz HPF. This was with three Seaton Submersives in a Room with a TON of room gain.

The results were very underwhelming --- and while a difference could be told - I would easily have picked the raw output of the pair of ported caps over the extra extension below 18Hz. It was so minimal it was hard to tell by nearly all accounts. --- having the HPF or not. IMO --- the only way you could tell with an HPF at 10hz --- is if the demo area was on a wooden suspended floor - or you were listening with an EXTREME house curve, AND you weren't listening with real world material at real world volumes. That's been my experience after testing with 14hz, 16hz, and 18hz HPFs in multiple different rooms on very capable systems including Carps (8 - 18"s), Desertdomes (8 - 15"s suspended floor), popalocks (16 - 18"s), and Gorilla83's. (six 15"s at the time).
Thanks for the strong post. It's right on the money from my point of view too.

If you can get that extension great! But if you need to give up output, or otherwise need/want more then it's a worthy trade off to take the output over the extension.

18hz is a tough one- I am thinking I want reasonably flat to 15hz for myself. That means usable output at 10hz usually. But If I can jump 10db in output at 20hz, by sacrificing the single digits- I'll do it. Chasing single digits becomes a game of inches- and each each costs you significantly, you'll start hitting electronic equiptment roll off, and/or really taxing the crap out of your drivers with a silly house curve to make it worthwhile.

The demo I got for a car audio demo showed me pretty much exactly what you are saying. I have a buddy that run a competition stereo install company and has a vehicle with (4) 15" sealed. He runs a 18hz high pass in that vehicle for sound quality, and I could not tell the difference which was which on the HULK scene, even at reference volume. I honestly could not tell if it was on or off- that opened my eyes a lot. The volume was loud. It was hurting my ears, probably above reference actually. I did not meter it, but I know when something is over 100db and this was.

Sensory perception is so poor at really low ULF bass that it has to be so silly loud to notice or appreciate it, and the difference without is really small. If you can dial up a 120db+ output house curve on the 20hz and under stuff I could see it being fun to flap your pant legs- but we are talking about the cream of the crop systems here. If you can blast teen and single digits louder than 120db, or you simply won't- just give up on the ULF chase now and save yourself the trouble. It's only fun and worthwhile if it's really loud!

It still kind of gets under my skin a tad when I see someone say they went sealed because they wanted the extension, and it's a single woofer system. Sealed is great because it's small, handles tons of power, simple to build, no phase issues with other sealed systems generally- but extension is really not a good reason. It's a slow dying myth or enlightenment about the volume thing- and how much silly volume you actually need to make ULF worthwhile.

I certainly can't criticize the uber systems of 8+ 18" woofers and tens of thousands of watts, cause that's fun! But the one and two driver systems just don't operate in the territory to make ULF worthwhile unless it's installed in a bathroom. I think that's probably the biggest myth. Not that ULF isn't real, but the actual reality of what it takes to get there. Personally the amount of house curve, EQ and all that to make it work doesn't seem worth it to me because it over taxes your amps and woofer causing higher distortion and less headroom/dynamics/output which I like more. But for the small select group that can do it and still have the output and headroom because of their total overkill system- I am jelly.
 

·
Registered
Joined
·
5,542 Posts
I’ve talked so much about the XXX drivers vs the LMS and others over the years.

Yes a XXX is handicapped in the 4cube test box. So were some other drivers. Here’s the thing that doesn’t really matter. What do I use for mine at home? 4.5 cubes each so basically what the drivers are tested in at DB.What do I mean by handicapped? The motor is not strong enough to really operate without some issues in that type of situation. The Q of the system is high so the response becomes even more peaky and combines with the inductance peak to hump the response up. Also this causes an issue where the excursion of the driver actually plateaus in the deep bass and the excursion maximum is more like 25Hz than at 10Hz or lower. The driver will also distort more in the deep bass. Air spring distortion in a box this size once you hit the really crazy excursion levels also starts to factor in. So to recap what happens if you were to put the XXX, or any other relatively low motor strength vs cone area driver in a sealed box that allows it to have a nice 0.6 Q versus a Q of 1.1? The deep bass efficiency goes up a lot obviously, but distortion also goes way down inthe deep bass, input power drops dramatically to generate the same output, ASD effects become minimized, etc. Now this all also applies to a much stronger motored driver like an LMS, but it was already operating quite happily in the 4cube enclosure with a system Q near 0.6 already. This is a much lower system Q than the XXX, so while it will also gain the same advantages in the big enclosure that gives the XXX the room it needs to breathe, it will not have as dramatic of an effect on the LMS and it will not lower its deep bass distortion as much by going to the bigger airspace. Take an extreme example like the 21IPAL…It has a system Q of 0.38 in 4 cubes and it is a larger 21. It really does not care about the enclosure volume much. Going from 5 cubes to 8 cubes on it won’t amount to nearly the amount of improvement that it would on an under-motored driver like a Fi IB or something. Maximum peak output will not change in the deep bass with a larger sealed enclosure because there is enough amp on hand to push the drivers to the limit already in the 4.2 ft box.

Everyone looks at CEA-2010 and assumes it is maximum peak output. That is a mistake. It is distortion limited especially in the deep bass. When you move a subwoofer into a domestic space there is typically a HUGE reduction in deep bass distortion. What may be 30% THD at 16Hz outdoors could turn into 10% inside your room. It is a major difference. The CEA-2010 chart which shows the actual maximum peak output and the voltages used is under the static graphs page for each system. The LMS IS at maximum peak output at 20Hz with the CEA-2010 testing as it was making a mechanical clack noise if the signal was increased even 0.1dB further. It is pretty much clean all of the way up to hard bottom. Most of the other long throw drivers are far from xmax in the lowest 3 CEA-2010 test bands when the distortion limit is met.

I’m not making excuses for the XXX I know its faults well. So why do I use it in the undersized cabs and why didn’t I use LMS’s or another set of drivers? Simple…They offer the most displacement I could get from 18’s. I do not worry about bottoming them ever. Even with an amp rated at 4500w peak to each driver they cannot be bottomed in those cabs. Maximum excursion is probably about 40mm at amp clip in the deep bass, so there is a good 15mm of xmech left in the tank. When I drive the amps to clip I can just start to get a bit of surround dimpling and a bit of excursion noise at which point I’m more worried about things breaking in my house. I can’t even get the damn things to sound bad with the power I have on tap. I could easily let the magic smoke out though with too much signal duration, so I worry about that more. Even with less power on tap I could have destroyed my LMS’s with one wrong signal. I was originally going to go with them but they made me worry. I wanted something that operates at only about 80% of xmax or less and was dummy proof from accidental mishaps. Any of the other big dog drivers on the market at the time might have survived but they would be at the ragged edge producing that much displacement and would either be in danger of mechanical bottom or audibly distorting severely. The only drivers that have come out since which have close to the same suspension and mechanical clearances are the ZV4’s (HST’s) but they are still slightly less and the motor does not have the BL curve of the split coil at the extremes. Speaking of the split coil XXX, those are no longer made. They are all over-hung now, which increases the inductance and motor strength but crashes the extreme linear stroke of the split coil version by radically altering the gap/coil geometry. Originally the split coil XXX was supposed to be a neo slug motor but they bailed on it due to costs. It would have had a much stronger motor. It’s too bad. I intend to replace all of mine someday but I haven’t found any drivers that improve the areas I want to improve without sacrificing the displacement and mechanical ruggedness. The LMS is a better performer in all aspects over the XXX and nearly every other driver, until it runs out of clearance and then things get expensive.

As far as the SI 24 goes I’ll just keep my opinion, which is simple and to the point, to myself until after the measurements are done and up on the website. However it must be noted that the 24 will be in a HUGE box. 15ft or something like that. It has 3.6x the airspace that the 18’s get. Of course it will have a deeper response and be more efficient + all of the distortion lowering advantages a bigger box gives in the deepest bass. If we wanted a true apples/apples comparison with the 18’s we’d need to test it in an 8ft sealed cab. Or it can be compared against 3 18’s in 4 cubes each which are still at a size disadvantage. The huge enclosure cannot be discounted from any comparison. It is one of the major components of Hoffman’s iron law after all.
 

·
Registered
Joined
·
10,474 Posts
@Ricci your fear of bottoming out the LMS was definitely founded. I couldn't live with them in sealed enclosures, even with 8 of them. When there's 7k in drivers and you hear them all reach xmech and clack at the same time, it's nerve wracking. After putting these in ported enclosures, it's clear my house will be destroyed before I even come close to hurting these drivers. As long as they're highpassed properly, I don't think I can even hurt them if I wanted to with an FP14000 channel per driver and normal content.
 

·
Registered
Joined
·
3,799 Posts
@Ricci your fear of bottoming out the LMS was definitely founded. I couldn't live with them in sealed enclosures, even with 8 of them. When there's 7k in drivers and you hear them all reach xmech and clack at the same time, it's nerve wracking. After putting these in ported enclosures, it's clear my house will be destroyed before I even come close to hurting these drivers. As long as they're highpassed properly, I don't think I can even hurt them if I wanted to with an FP14000 channel per driver and normal content.
It is nice that they "clack" well before turning into a mushroom, though!

I feel the same way. With the filters I have on them I'd have to be a complete idiot to damage them, even with 5.5kw of power going to each one.
 

·
Registered
Joined
·
10,474 Posts
It is nice that they "clack" well before turning into a mushroom, though!

I feel the same way. With the filters I have on them I'd have to be a complete idiot to damage them, even with 5.5kw of power going to each one.
There's not much room between clack and omfg mushrooms... and that was happening with a filter.
 

·
Registered
Joined
·
3,799 Posts
There's not much room between clack and omfg mushrooms... and that was happening with a filter.
How many years did you have them sealed? How many times did you clack them? Have you mushroomed a cone?

I clacked then a few times while sealed, and a few times in the Ghorns, but they've survived. I think they're more durable then people give them credit for.
 

·
Registered
Joined
·
19,256 Posts
Discussion Starter #816
We did it at gorrilla83's to a degree --- not ABX - but rather AB, and with about 15 to 20 people --- but we used an 18Hz HPF. This was with three Seaton Submersives in a room with a TON of room gain.

The results were very underwhelming --- and while a difference could barely be told -- and I do mean barely --- most did guess right -- including myself --- However --- beyond a shadow of a doubt -- I would easily have picked the raw output of three ported caps over the extra extension below 18Hz on the three submersives as my favorite. It was so minimal it was hard to tell by nearly all accounts present. --- in which demo had the HPF or not. It didn't make big waves at the forum --- and when we brought it up we were told that the three Submersives weren't the right sub to test with. Blah --- Gorilla83's room gain is so ridiculous a 15" sealed sub in his room has more low end gain than a pair of 18" sealed in my previous, and current room.

IMO --- the only way you could tell with an HPF at 10hz --- is if the demo area was on a wooden suspended floor - or you were listening with an EXTREME house curve, AND you weren't listening with real world material at real world volumes. That's been my experience after testing with 14hz, 16hz, and 18hz HPFs in multiple different rooms on very capable systems including Carps (8 - 18"s), Desertdomes (8 - 15"s suspended floor), popalocks (16 - 18"s), and Gorilla83's. (six 15"s at the time). Even desertdome with his 8, 15" subs mounted DIRECTLY to the wooden suspended floor (hanging into the crawl space) has determined below 14hz doesn't matter to him. I still need to experience MK's room - but I've not been convinced otherwise yet - and I'm having a hard time believing that'll change after exeperiencing popalock's room.

Another time you might be able to notice less than 10hz would be if the sub is firing directly into your back - nearfield.

The very low stuff has never been about that holy crap moment like in FOTP barrel roll. It is about weight to the bass and feeling real. The Lone survivor helicopter feels very different than other loud helicopter scenes. It feels like the heli is in the room. If I low pass out the Bass I love you 6hz stuff I still get great bass, but I don't get all of it, simple as that. You can feel each pulse from that 6hz stuff, literally like puffs of air. My seats are on all wooden risers with nearfield(4 feet to center seat and closer to the rest) subs.
 

·
Registered
Joined
·
3,799 Posts
The very low stuff has never been about that holy crap moment like in FOTP barrel roll. It is about weight to the bass and feeling real. The Lone survivor helicopter feels very different than other loud helicopter scenes. It feels like the heli is in the room. If I low pass out the Bass I love you 6hz stuff I still get great bass, but I don't get all of it, simple as that. You can feel each pulse from that 6hz stuff, literally like puffs of air. My seats are on all wooden risers with nearfield(4 feet to center seat and closer to the rest) subs.
I heard beastaudio's system, and other systems capable of over 130db at 10hz, and I'm still not convinced sub 15hz is worth chasing while on a concrete slab.

I wouldn't trade a system capable of 135db from 15-35hz for a system capable of 125db from 8-35hz. I've heard both, all on concrete floors, and it just doesn't do it for me.

Call it "inaccurate response" or "less real" or whatever you want, but I listen to what I like. Simple as that.
 

·
Registered
Joined
·
10,474 Posts
How many years did you have them sealed? How many times did you clack them? Have you mushroomed a cone?

I clacked then a few times while sealed, and a few times in the Ghorns, but they've survived. I think they're more durable then people give them credit for.
I was aware of the issue since I slowly increased levels demoing stuff. I never pushed them as hard as I wanted to with material that could do it, and I put a highpass on em pretty quick. I didn't damage any thankfully.
 

·
Registered
Joined
·
21,319 Posts
"As far as the SI 24 goes I’ll just keep my opinion, which is simple and to the point, to myself until after the measurements are done and up on the website. "


since you are keeping your opinion to yourself, i'll go ahead and share mine: 115db @20hz--more output than any other single woofer in a sealed enclosure to date by a wide margin. :)~


---


more importantly, great posts guys. while the power density of sealed, ultimately, can't be disputed, the comments on the practical value of ulf should be quite helpful to the new guys who are trying to figure out what to shoot for (at least to get started).



 

·
Premium Member
Joined
·
14,808 Posts
How many years did you have them sealed? How many times did you clack them? Have you mushroomed a cone?

I clacked then a few times while sealed, and a few times in the Ghorns, but they've survived. I think they're more durable then people give them credit for.
Yea, as Not said above, the LMS can go bonkers real quick and mushroom if you accidentally bypass the clacking stage and go too hard too fast. That is how most end up getting that nice new cone design on their LMS drivers. They are drag racing with them and just going to 11 immediately.
 
801 - 820 of 928 Posts
Top