Looking for high 15hz SPL and great SQ - TC Sounds LMS 5400 Ultra? - AVS Forum
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post #1 of 23 Old 07-18-2011, 09:37 PM - Thread Starter
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If I were looking for the best ported subwoofer to put out very high spl down to 15hz and really great sounding, as in looking for the lowest THD, highest SQ I can possibly find, would the TC Sounds 18" LMS 5400 Ultra be the best driver to use? With a Crown XTI 2000 maybe? Would a commercial offering be better?
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post #2 of 23 Old 07-19-2011, 05:04 AM
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The LMS 5400 is a great driver, but to help you, the group will need more information.

Budget?
How big can the box or boxes if multiples of other drivers are used?
Room size?
Sealed or vented?

The Crown XTi is a nice amp, but IIRC it rolls off around 20hz according to some tests here on the forum. I think it is more appropriate for full range duty than it is for subwoofer duty.

According to my models, 2000w is about right for a 5-6 cu ft internal volume box assuming some rolloff in your electronics around 5hz. The LMS can handle this without an issue.
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post #3 of 23 Old 07-19-2011, 10:24 AM
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The LMS 5400 does not have Large Low Tuned friendly TSP's. The box required to get a port with a large enough cross section means you get a huge peak at the tuning frequency and a strong sloping shelf in the frequencies above it.

For example, tuned to 15hz, 12ft gives you a -5db EBS. The largest port size you could use and keep the 1st port resonance around 200hz is 12" x 3". With 2500w of power, that puts your port speed at 58m/s.

To get a box with a large enough port to keep chuffing to a minimum (<30m/s) and the 1st port res at 200hz or higher is impossible with the amount of power handling/excursion the driver has. The larger the box gets, the more it augments the port, so port speed increases proportionally to box volume. This is why folks use passive radiators.

The LMS-R 15's have the same problem. High excursion woofers overload ports if you tune low. Expect port speeds to reach around 40-45m/s at near maximal output. The LMS 5400, will have even higher port speeds.

YID DIY
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post #4 of 23 Old 07-19-2011, 10:31 AM
 
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What about the PRO-5100, though it's $1270 these days?

Let's say the JTR Captivator in 15Hz tune is the commercial reference here. 30″ x 20″ x 22.5″, $1499 without power. Jeff claims 121dB at 15Hz 1m GP sine with 4000w. Say 115-118dB at 15Hz with ~2000w is the ballpark goal here.

Can DIY outperform?
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post #5 of 23 Old 07-19-2011, 11:08 AM
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Well yeah, if you don't mind chuffing and port compression, you can throw an LMS 5400 in a 12ft box tuned to 15-16hz and find a high power amp (crest 8002?) and provide more output than the captivator.

There's no reason to get the more expensive pro5100 for use in an LLT. Less excursion and more cost.

YID DIY
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post #6 of 23 Old 07-19-2011, 11:16 AM
 
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Well obviously you have to roughly match the same size unit (the Cap isn't even 8 cubes externally) and performance outside of output (who thinks chuffing is acceptable?) with similar power costs applied to each.

Are you saying this is something DIY can't touch? And if so, doesn't that answer the OP's question?

The only reason I ask is because the OP didn't provide details, but asked if a commercial offering would be better. So you might as well make the JTR Cap the reference for budget, size and performance here.
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post #7 of 23 Old 07-19-2011, 11:37 AM
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I didn't read the OP as asking for a 15hz tuned setup but instead a sub capable of 15hz. If he wants 15hz tuned, go with passive radiators.
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post #8 of 23 Old 07-19-2011, 11:49 AM
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There is no reason DIY can not beat a $1500 passive comercial offering. The LMS5400 is cheaper and a better driver so alone that is a better design $1K. LMS5400 + 2PR is probably close to the $1500 figure and that is a better performance design.

Want to get closer to $1500 then how about a Dual sealed NS-18 design. That would be a superior passive design too.

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post #9 of 23 Old 07-19-2011, 11:55 AM
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Quote:
Originally Posted by penngray View Post

There is no reason DIY can not beat a $1500 passive comercial offering. The LMS5400 is cheaper and a better driver so alone that is a better design $1K. LMS5400 + 2PR is probably close to the $1500 figure and that is a better performance design.

Want to get closer to $1500 then how about a Dual sealed NS-18 design. That would be a superior passive design too.

+1 on the dual NS-18s. I'd take that over an LMS with dual PRs.
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post #10 of 23 Old 07-19-2011, 12:21 PM
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Originally Posted by coctostan View Post
+1 on the dual NS-18s. I'd take that over an LMS with dual PRs.
Are the NS-18's good for ULF?
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post #11 of 23 Old 07-19-2011, 12:54 PM
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ULF is a function of displacement and power handling. The NS18 has 25mm of xmax and is an 18. Therefore dual NS18s (50mm total xmax) will outpace a single LMS 5400 with 38mm of xmax. Then it is a question of how little you need the box to be, what the excursion profile looks like and how much power you can afford. A single LMS can work in a smaller box than dual NS18's but you only get about 2/3 the ULF output.

Power handling edge goes to the single LMS (2000w) vs dual NS18s (1600w) total. That is constant power and in reality either can handle power well beyond that in actual use...at least thermally. Excursion wise, it is a function of box size.

Dollar for dollar, they are equivalent at the current prices. On paper, the NS18 should be a better driver from a SQ perspective (lowest inductance 18" I've ever seen), but the LMS is no slouch and it may not be a discernible difference.
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post #12 of 23 Old 07-19-2011, 12:56 PM
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Quote:
Originally Posted by coctostan View Post
ULF is a function of displacement and power handling. The NS18 has 25mm of xmax and is an 18. Therefore dual NS18s (50mm total xmax) will outpace a single LMS 5400 with 38mm of xmax. Then it is a question of how little you need the box to be, what the excursion profile looks like and how much power you can afford. A single LMS can work in a smaller box than dual NS18's but you only get about 2/3 the ULF output.

Power handling edge goes to the single LMS (2000w) vs dual NS18s (1600w) total. That is constant power and in reality either can handle power well beyond that in actual use...at least thermally. Excursion wise, it is a function of box size.

Dollar for dollar, they are equivalent at the current prices. On paper, the NS18 should be a better driver from a SQ perspective (lowest inductance 18" I've ever seen), but the LMS is no slouch and it may not be a discernible difference.
Thank you, can we horn load it like the F-20? Maybe a JTR OS clone or something like it?
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post #13 of 23 Old 07-19-2011, 12:58 PM
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Quote:
lowest inductance 18" I've ever seen

Inductance does not matter compared to other design parameters when it comes to subwoofer performance, if we start running them higher then it becomes a factor.

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post #14 of 23 Old 07-19-2011, 01:27 PM
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Quote:
Originally Posted by penngray View Post
There is no reason DIY can not beat a $1500 passive comercial offering.
My signature and I couldn't agree more
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post #15 of 23 Old 07-19-2011, 01:51 PM
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Quote:
Originally Posted by MKtheater View Post
Thank you, can we horn load it like the F-20? Maybe a JTR OS clone or something like it?
I should have qualified that this is the case for sealed and vented enclosures. Horns are a different bag although also excursion limited.

These drivers would need to be modeled to see if it is viable. IMO, these highly linear large excursion drivers are generally not the best candidates for horns. Even if they model well, you are kind of wasting them in a sense. Horns are inherently bandwidth limited and these drivers really excel at providing a both significant ULF output and clean upper frequency output. At least that is their best use in a home setting. They might have a use in a pro setting where required output levels above 20hz could reach 130db+ and might need signficant power handling.

With the LMS, you are mainly paying for the ability play very low in the smallest box possible and to do so with good quality in upper frequencies to boot (The Re XXX drivers could do the same sans the quality upper frequencies).

I'd ask LilMike or Maxmercy to model them. I can work hornresp, but I'm not good at it like they are.
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post #16 of 23 Old 07-19-2011, 02:00 PM
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Quote:
Originally Posted by coctostan View Post
I should have qualified that this is the case for sealed and vented enclosures. Horns are a different bag although also excursion limited.

These drivers would need to be modeled to see if it is viable. IMO, these highly linear large excursion drivers are generally not the best candidates for horns. Even if they model well, you are kind of wasting them in a sense. Horns are inherently bandwidth limited and these drivers really excel at providing a both significant ULF output and clean upper frequency output. At least that is their best use in a home setting. They might have a use in a pro setting where required output levels above 20hz could reach 130db+ and might need signficant power handling.

With the LMS, you are mainly paying for the ability play very low in the smallest box possible and to do so with good quality in upper frequencies to boot (The Re XXX drivers could do the same sans the quality upper frequencies).

I'd ask LilMike or Maxmercy to model them. I can work hornresp, but I'm not good at it like they are.
Again thanks for the info, I did ask the question to lilmike and Maxmercy.
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post #17 of 23 Old 07-19-2011, 02:32 PM
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How high in frequency do you want it to go, and then what are the constraints on the enclosure size?

I'd recommend a more potent amp than the XTi 2000 if you really want to push the LMS-5400 to its limits.

-Mike Bentz
~It's all about compromise~
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post #18 of 23 Old 07-19-2011, 03:43 PM
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Originally Posted by penngray View Post
Inductance does not matter compared to other design parameters when it comes to subwoofer performance, if we start running them higher then it becomes a factor.
I'd have to disagree unless you low pass your sub around 40hz. Is the NS18's .68mh better than the LMS 5400's 2.80 in a significant way? I don't know. There is some point where inductance becomes an issue. Beyond that, how inductance changes as a voltage is applied can cause distortion.

I don't think it is any coincidence that Aurasound, AE AV series, JBL 2242/2245, etc all have motors designed for very low inductance. It does become a factor from the 50-120hz range, IMO the most important range for a subwoofer's subjective sound quality. This is the range that separates the men from the boys. It would be much cheaper and easier to build a motor with no regard for inductance.
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post #19 of 23 Old 07-19-2011, 03:47 PM
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I'd have to disagree unless you low pass your sub around 40hz. Is the NS18's .68mh better than the LMS 5400's 2.80 in a significant way? I don't know. There is some point where inductance becomes an issue. Beyond that, how inductance changes as a voltage is applied can cause distortion.
How can you disagree when you do not know about the audibility? I do know about it. You have to have audible proof until then its someone's silly little theory. Distortion levels in bass systems is a big red herring to start with. The room causes more noise then most designs that adds to the masking effects. You also miss an important part of the point "compared to other design parameters".

My conclusions, Not an audible one at all. There is no difference and distortion rates this low are always masked. Every controlled listening test proves this and I have enough different subwoofers to understand that as long as they are all played within their limits there is ZERO audible distortion.

Its all about knowing what your displacement and headroom goals are.

Example. There is ZERO audible difference between 4 Q18s and 1 LMS5400 when played in the performance range of the Q18s (you have to figure out that range), The Q18s beat the LMS5400 with clean output too. I also have the AV15X drivers and the TD series drivers both with ultra low inductance....bass performance does not care one bit about all this splitting hairs debates when we understand the performance range of each design. What seperates the LMS5400 is what it does in a smaller box that is all. There is nothing special about the NS-18 other then it has decent displacement and it also has the ability to play well in a smallish box. If someone has a place for monster boxes then 4 Q18s is a better choice over all.

Lets face it, no one is going to be able to even tell the differences here, they will just know they all sound amazing compared to what others buy (ie. crap little subs). Once you get into multiples all those little numbers and nitpicking goes away because once displacement is past X liters, everything else works with ease. Put 4 NORMAL PEOPLE in a room and run the test.....its so damn easy to know there isnt much difference but the splitting hairs debates online sometimes makes mountains out of mole hills, its all noise, its like a stocktrader watching CNBC or political hacks watching FOX or MSNBC, its all noise!! Sometimes all the subjective nitpicking has to be turned off and realize that EITHER quality choice is 1000 times better then something BIC or Polk offers.

I welcome everyone to start buying more and start testing more and all these back and forth discussions would end faster

Quote:
I don't think it is any coincidence that Aurasound, AE AV series, JBL 2242/2245, etc all have motors designed for very low inductance. It does become a factor from the 50-120hz range, IMO the most important range for a subwoofer's subjective sound quality. This is the range that separates the men from the boys. It would be much cheaper and easier to build a motor with no regard for inductance.
hehe, Caught this....You do know why I own TD series and AV series drivers right?? Im not debating the significance of inductance above 80Hz at all, obviously its important and I have posted many times of what specs I think matter in those drivers (Le being a very important one) but anything in the lower frequencies is completely meaningless. Look at the distortion charts and compare. Remember measurements is our friend there isnt any mysterious/golden ears soundwave that can not be measured

There are many ways to design a systems, to me its all about headroom. Increase the headroom to remove the nitpicking BS that goes on about this driver vs that driver. If Im driving any 18" woofer at 10% Im not getting distortion. It does not matter if its $200 or $900.

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post #20 of 23 Old 07-19-2011, 04:51 PM
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Penn-

I generally agree with you here. When you compare a high inductance sub driver vs a low inductance sub driver, I've noticed it in the 50-80hz range, but it is definitely an issue from 80-120hz. IMO, being able to cross your sub up at 120hz instead of 50,60 or 80hz is a big advantage.

I'm totally with you on more drivers and headroom making this all moot (I have 12 sub drivers), but most people are in the 1 or 2 driver boat with limited space. In that case, like for the original poster, the driver's motor becomes more of an issue. It is not only an issue of displacement. In that case, nobody would buy LMS 5400s. They'd all buy Re XXX 18's which have 54mm of xmax for $1000...but are a high inductance design (8.9mh). There are a whole bunch of car audio drivers that are similar because the pure SPL crowd doesn't care about how clean a driver is from 50-120hz.

The LMS isn't as low on inductance as the NS18, but like I said, I doubt you'd be able to distinguish the two. The LMS is still a low inductance design and low enough that it won't matter out to 120hz. It was more of a tie goes to the runner situation.

Audibility? Objective measurements? Is this the same guy that prefers his ribbon sparkle over the compression drivers?

On a side note, you could have a pretty sweet system with a single RE XXX 18 in about 10 cu ft crossed over around 40hz and a few small inexpensive bandpass or sealed subs for the 40-120/150hz. Stick the XXX in a corner and move the tiny BP subs wherever FR turns out best. The RE XXX is the only single driver I know of that has the potential to do 115db at 10hz in room.
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post #21 of 23 Old 07-19-2011, 06:15 PM
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Penn, do you normally watch movies or listen to music? Do you think all amps sound the same too? I've done lots of blind listening to both, but haven't really arrived at the same conclusions. I definitely agree with the sentiment though.

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post #22 of 23 Old 07-19-2011, 06:22 PM
 
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Quote:
Originally Posted by coctostan View Post

I didn't read the OP as asking for a 15hz tuned setup but instead a sub capable of 15hz. If he wants 15hz tuned, go with passive radiators.

You're right, it wasn't very specific. He did say: "best ported subwoofer to put out very high spl down to 15Hz", and: "Would a commercial offering be better?"

In either case, I think the Captivator in 20Hz or 15Hz tune is still the commercial reference to go by.

So can an LMS + dual PR hit 115-118dB at 15Hz with ~2000w in a roughly 8 cuft external form factor like the Cap? And if not, what can?
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post #23 of 23 Old 07-19-2011, 07:45 PM
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Quote:
Originally Posted by BiGBADDABOOM View Post

You're right, it wasn't very specific. He did say: "best ported subwoofer to put out very high spl down to 15Hz", and: "Would a commercial offering be better?"

In either case, I think the Captivator in 20Hz or 15Hz tune is still the commercial reference to go by.

So can an LMS + dual PR hit 115-118dB at 15Hz with ~2000w in a roughly 8 cuft external form factor like the Cap? And if not, what can?

I don't know how I missed the ported part. Most people use the LMS in either sealed or PR applications.

So I looked up the Capitivator. It is an 18" driver with 30mm of xmax. Let's guess the volume of the box is 7 cu ft and it is tuned to 20hz or 15hz with a plug. It has a slot port that is about 18" wide and maybe 2.5" tall. By my calculations, the Captivator, when pushed to around 120db @ 20hz will have a port velocity of around 140 ft/s which equals major port compression and chuffing. For the 15hz tune, halve the port CSA and you are talking > 180ft/s.

Honestly, there isn't anything special about that sub. I'm not saying it is a bad sub, but we are just talking about a small vented sub with lots of excursion. You could swap in the LMS and get similar results. Any box that small is going to be port limited, not driver limited.

JTR's claims of 120db @ 15hz in half space are a red herring unless he's been able to rewrite the laws of physics.

Basically you could put the LMS in that box and give it 4000w and get virtually the same results although I'd guess the LMS is a superior driver or JTR isn't making a dime.
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