TC Sounds LMS-R 15" or DC Audio Level 4 15"?

[T3mpest 10+ year member]

I doubt the power compression is much different between the LMS and the AV. The AV does use a smaller coil but the gap is alot tighter on the av, hence the lower q. That definetly helps draw heat away because even if dont' necessarily have more coil, you do have more steel right there to help draw heat away, along with the faraday rings as well. The LMS's extra powerhandling advantage, which probably isn't as big as it normally is between a 2.5 and 3 coil is still negated up top anyway due to effeciency. The AV is alot more effecient up top, 3db's worth is double power and it keeps that across half the bass spectrum basically 50hz to the crossover. If he had more box size I'd say the tempest X woudl be the best choice. 3.5 cubes or so would be killer.

 

[rc10mike 10+ year member]

Im sure that everyone on here has actually used a LMS-R....

 

[T3mpest 10+ year member]

I know ppl that have used the older ones, but I dont' know of anyone who has tried the new ones yet. The price is finally about right though, glad parts express knocked them into the realm of a reasonable purchase.

 

[SmoothSQ 10+ year member]

frequency response is a function of cabin gain box size and QE/FS as well as inductance..
while the graphs show the tempest and AV louder down low they won't even touch the LMS-r in powerhandling.. and not to mention power compression.. if i was going to seal the drivers Id use the lms in a heartbeat.. they will have a lower F3 and have much lower power compression at any given input not to mention its one of te most linear designs in stroke.. its biggest downfall is its LE which is fairly high but if you have a good amp with excellent dampinng its going to sound excellent reguardless.. the problem today is simply the damping factors @ 1ohm are low enoguht for the back EMF to cause inproper cone control and terrible freq response..

Regarding inductance, what range do you consider to be "fairly high"? I don't know what is high and what isn't. With the LMS-R coils in parallel the inductance is about 1.13mH. I'm using some 12s right now that have in inductance of .81mH (coils in parallel), which isn't (at least not to me) a great deal lower than the LMS-R -- and they play just fine @ 1 ohm.

The 12s that I have now use a "Variable Q" technology. When I had the "mid q" insert in them, they had tremendous output down low, but not much beyond about 60hz. I switched to the "low q" insert and now they have awesome upper bass extension, but the lows are pretty anemic, lol.

I need something in between those two.

It would really make me angry if I spent nearly $300 dollars shipped on the AV15-X if it's response ended up being just like my 12s with the "low q" insert.

It would also make me mad if I spent over $300 for the LMS-R if it's response turned out to be just like my 12s with the "mid q" insert.

One more thing....I asked a tech at TC Sounds if transient response was dependent upon the inductance of the sub, the qtc of the enclosure, or both -- and he said the transient response is solely dependent upon the qtc of the enclosure. Is that correct?

 

[SmoothSQ 10+ year member]

Based on the response of my 12s with the "mid q" insert, I think I would be satisfied with a mid-q sub that could play up just a little bit higher -- to about 70hz.

If the Fs helps shape the sub's frequency response, I'm guessing a mid-q sub with a higher Fs (around 27-30hz) would suit my taste perfectly. My 12s have an Fs of 22hz.

The Diamond Audio d615 (dual 4 ohm version) has an Fs of 28hz, but it's a high-q sub, and I'm wondering if that changes things considerably or not.

 

[Papermaker85 5,000+ posts]

I doubt the power compression is much different between the LMS and the AV. The AV does use a smaller coil but the gap is alot tighter on the av, hence the lower q. That definetly helps draw heat away because even if dont' necessarily have more coil, you do have more steel right there to help draw heat away, along with the faraday rings as well.

both woofers have faraday rings.. the LMS coil is longer and substantially larger in diameter.. not to mention the QE on the LMS is only offset by the high MMS IE its a pretty **** tight gap as well.. the LMS coil has nearly double the surface area equally tight gap and faradays as well.. im sure TC will tell you its rated for 1k because its a warranty issue but i assure you they will take 2kw with NO problems.. also you have to understand that steel as it get hotter its conductivity both magnetically and thermally deteriorate..

The LMS's extra powerhandling advantage, which probably isn't as big as it normally is between a 2.5 and 3 coil is still negated up top anyway due to effeciency. The AV is alot more effecient up top, 3db's worth is double power and it keeps that across half the bass spectrum basically 50hz to the crossover. If he had more box size I'd say the tempest X woudl be the best choice. 3.5 cubes or so would be killer.

you cannot go by a freeair 1w1m function... the LMS is not going to be nearly as peaky in any alignment.. IE its less efficient in exchange for a wider bandwidth. the true "efficiency"rating for a woofer is the actual inuput in wattage VIA electrical to the intestity of sound output Via mechanical.. IE the more efficient driver is going to be peaky free air and in its recommended alignments.

after all its not output hes craving its a flatter frequency response he wants..

to the OP.. if you put the LMSR in a smaller box it will increase the output as frequency rises and vice verser with the AV use a larger box to get more lowend..

 

[Papermaker85 5,000+ posts]

after modeling up there going to be nearly identical with the AE having about .5 output advantage below 45 but the lms can and will handle more power and has more displacment..

 

[RAM_Designs 5,000+ posts]

Dayton Reference HF is my new bargain boner sub for sealed boxes...f3 in the upper 30's for the 12"er in a 2ft^3 box, and just a good sounding woofer IMO. 1mH inductance FTW.

Granted, it's not going to be able to handle the same power as other woofers being talked about in this thread.

 

[SmoothSQ 10+ year member]

@Papermaker

I appreciate you going through the trouble of modeling the subs and posting it here. I have a couple of questions.

1.) What size box did you model the subs in on your program?

2.) You said a smaller box would put more emphasis on the upper bass range, that means a higher qtc. So how high of a qtc can a person use before it noticeably affect the woofer's transient response?

 

[Papermaker85 5,000+ posts]

1) the first plot is identical to the second i accidentally posted the same one twice,lol..

their both in 2 cubes sealed..

2)

the transient response for both woofers IE its ability to stop when its supposed to stop in its simplest form are going to be pretty similar.. the QTC for the TC is abit closer to critically damped.. this is with max fill and a QL of 10(ie leakage).. ill model them up with a QL of 0(IE no leakage) so you can see the variance..

QTC is often misunderstood and misused.. some people don't like the low Qe "overdamped" woofers they often sound too tight, punchy,dry and vice verser the higher Qe woofers sound loose,bloated but fuller.. its a matter of over shooting and rest time.. IE over-damped motors overshoot with controlled oscillations.. IE the cone goes past rest in one direction and changes direction and inertia takes the mass the other way progressively slowing down.. the higher the damping the more resistance it sees but the more oscillations..IE is less stroke but happens faster.. where under-damped is the opposite. its less oscillations but longer strokes.. critically damped means it has the fastest return time where stoke and oscillations are ideal for that given frequency..

 

[SmoothSQ 10+ year member]

their both in 2 cubes sealed..the QTC for the TC is abit closer to critically damped.

WINisd and an online qtc calculator showed that the AV would have the lower QTC for any given enclosure volume.

As long as the sub plays gets reasonably low, plays up to 70hz, and doesn't sound sloppy, I'm good.

 

[Cruzer 10+ year member]

i vote AE AV15.

 

[Papermaker85 5,000+ posts]

both sound amazing.. i say buy both listen to both and sell the one you like least.. just use both woofers ideal box (.707qtc)

 

[SmoothSQ 10+ year member]

both sound amazing.. i say buy both listen to both and sell the one you like least.. just use both woofers ideal box (.707qtc)

I wish I had enough money to throw away where that wouldn't be a problem.

It would cost me over $600 for both subs, and if I used your advice on putting both subs in a butterworth alignment, I would then also need 2 custom made sealed boxes -- because both subs require a different volume of air space for a .707.

That would be around $800 total. Probably a lot closer to $900 realistically. I would get some money back if someone bought the sub that I didn't wanna keep, though it would be at a fraction of the price that I bought it for, and I might still be stuck with a custom enclosure that ends up being an absolute waste of money.

I'm in school and can't afford to be a spendthrift.

I'll just take all the advice that I've received in this thread into consideration before making my purchase. I want to buy one of the two subs either later on tonight or tomorrow. Thanx for your help.

 

[RAM_Designs 5,000+ posts]

^^^you can make both boxes out of one sheet of MDF...