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Discussion Starter · #1 ·
I just bought a used Audiopulse LMS 15" driver that's in mint condition at Ebay, at a great price. I guess I could not resist the temptation. It will be going in a 7cf birch-ply enclosure (internal) w/18" PR's that I have, tuned to 16hz and powered by ED LT1300 plate amp, (1,300watts).

I realize this sub takes a lot more power than what I currently have. I also realize that my enclosure is quite a bit more efficient than a sealed one for the low bass. The LMS driver in a sealed sub takes 3,000-4,000watts with no problem. Do I need that kind of power in my set-up? Also, since this is a heavy driver and my PR box has only a 1.5" front baffle (actually only 3/4" to mount this driver since it will be flush mounted). Can I do a basic wood support inside the enclosure to help support the weight of the sub's motor?

I like to use plate amps for their convenience and also, I have very little space in my rack system for a pro amp. Funky Waves might be selling a plate amp soon from some of the comments I hear at AVS Forum. It has very good specs for a plate amp, rated at 2,400watts at 4ohm. If I end up needing more power, this is a plate amp I might just get for my LMS driver. It almost doubles the power of my LT1300 plate amp. This sub would be replacing the AV15X sub I'm currently using in my 6,000cf room. I'm guessing both driver's SQ should be similar with perhaps the LMS having the edge, no? The LMS driver should have quite an advantage in the low bass compared to the AV15X sub. What do you guys think?

Finally, if someone wants to model for me the Audiopulse LMS 15" driver in my enclosure with 2,000watts and the AV15X driver with 1,000watts in that same enclosure, tuned to 16hz, to compare their performance, I would greatly appreciated.
 

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If there is no other way to make your baffle thicker so you can use heavier longer screws then i don't see a problem with buiding a support in the enclosure but it might take some precision work to get the sub so it sets in the brace properly.:bigsmile:
 

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I just bought a used Audiopulse LMS 15" driver that's in mint condition at Ebay, at a great price. I guess I could not resist the temptation. It will be going in a 7cf birch-ply enclosure (internal) w/18" PR's that I have, tuned to 16hz and powered by ED LT1300 plate amp, (1,300watts).

I realize this sub takes a lot more power than what I currently have. I also realize that my enclosure is quite a bit more efficient than a sealed one for the low bass. The LMS driver in a sealed sub takes 3,000-4,000watts with no problem. Do I need that kind of power in my set-up? Also, since this is a heavy driver and my PR box has only a 1.5" front baffle (actually only 3/4" to mount this driver since it will be flush mounted). Can I do a basic wood support inside the enclosure to help support the weight of the sub's motor?

I like to use plate amps for their convenience and also, I have very little space in my rack system for a pro amp. Funky Waves might be selling a plate amp soon from some of the comments I hear at AVS Forum. It has very good specs for a plate amp, rated at 2,400watts at 4ohm. If I end up needing more power, this is a plate amp I might just get for my LMS driver. It almost doubles the power of my LT1300 plate amp. This sub would be replacing the AV15X sub I'm currently using in my 6,000cf room. I'm guessing both driver's SQ should be similar with perhaps the LMS having the edge, no? The LMS driver should have quite an advantage in the low bass compared to the AV15X sub. What do you guys think?

Finally, if someone wants to model for me the Audiopulse LMS 15" driver in my enclosure with 2,000watts and the AV15X driver with 1,000watts in that same enclosure, tuned to 16hz, to compare their performance, I would greatly appreciated.
I have a TC Sounds driver and use a 500 watt amp with it even though it can take 1000 watts. I don't see any harm in this just be aware it could clip like crazy so having a power amp with trims is probably a good idea in this case. The LMS drivers have more extension but the AV15x has more upper bass from what I've seen. You will need to give us the T/S parameters of the P-Rs for me to run the numbers.
 

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I have a TC Sounds driver and use a 500 watt amp with it even though it can take 1000 watts. I don't see any harm in this just be aware it could clip like crazy so having a power amp with trims is probably a good idea in this case. The LMS drivers have more extension but the AV15x has more upper bass from what I've seen. You will need to give us the T/S parameters of the P-Rs for me to run the numbers.
Looking at the numbers, and the brand of the driver, I'm going to guess the pr's are the 18-2100's from AE. The parameters of them are easy enough to find, or shoot me a PM if you want to have a play with them.
 

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It looks ok. You will have a slight peak near tuning, due to that being a large box for that driver. The driver could safely use a 3500-4000w amp down to near 14hz in your set-up while staying near xmax, but the PR's would be overdriven near tuning with that much power.

Do not worry about adding a magnet brace. My 18" LMS is mounted in an enclosure with a baffle the same as yours and it has been driven hard and moved around quite a bit. Just do not drop the enclosure from 2ft off of the ground. :T


Oh BTW,

Check the downloadable winisd files section. I dumped a mountain of drivers in there a while back and this is one of them.

http://www.hometheatershack.com/for...on/14410-downloadable-winisd-pro-files-2.html
 

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Discussion Starter · #7 ·
First of all, thanks to everyone for your responses.

Moonfly, yes, the PR's are the AE 18-2100. Here are the specs of the AE 18-1600, the only ones I could find;
Fs: 4HZ
QMS: 85
Vas: 1840L
Mms: 1600 G
Sd: 1200 sq.cm.
Vd: 9L
Xmax: 3" P-P
Here are the specs for the Audiopulse LMS-Ultra 15" driver (I could not find its Le or Qms).
Qts: .28
Re: 4.0
Fs: 20Hz
Vas: 127 lit
Mms: 452 G
BL: 27.5 TM
Sd: 0.082 m
SPL: 87.3 DB
B2/Re: 185 N/W
Xmax: 38mm
Rec. Amp. 5,000 watts

Isiberian, yes, the AV15X sub has more mid-bass than the TC2000/3000 subs (I had the 3000 which had better low bass but quite a bit less mid-bass performance than the AV15X sub). On the other hand, the LMS drivers are different animals, probably the best sub driver out there, but it's costly. I got mine for $650 w/shipping included, not bad, no? Anyways, I would think with the same power applied in my PR enclosure, say 1,000watts, the LMS should give me as much mid-bass as the AV15X driver with more SPL in the low bass which is something I need in my big room. Of course, while the AV15X driver would be reaching its limit with 1,000watts in my enclosure, I could feed the LMS driver 2,000watts easy, for another 3db gain.

Ricci, if I do decide to upgrade my amp, it would probably be around the 2,500watts area, basically doubling my current power. Will my PR's take that power without being overdriven? It's good to hear that your LMS works fine screwed to just 3/4" wood. I just might let the brace idea for the LMS motor go, we'll see.

bambino, if I do decide to do the brace for the LMS driver I do realize it will take some precision to get it done. Working with wood is one of the things I like to do, so I should be o.k.
 

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Discussion Starter · #8 ·
Ricci, if I do get a small peak around tuning it should not be a big problem since I'm using a Rane PE 17 Parametric EQ to take any peaks down, what do you think. My biggest concern is that my home circuit breaker being 15amps, might not be up the task if I upgrade to a 2,000- 2,500watts amp. Changing it to a 20amps should not be that difficult, right? What about the wires? I read than 15amps usually have #14 wire while 20amps require #12 wire, is that the case? If so, that would be more complicated. So far, all my AV gear has been running fine with the stock 15amp breaker.
 

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If you are up to the task of building an enclosure for a sub like that there is no way i would question your skills. Even though you commonly don't see the inside of the enclosure i do find the brace work that some of the guys put in to be artwork.:sn:
 

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Isiberian, yes, the AV15X sub has more mid-bass than the TC2000/3000 subs (I had the 3000 which had better low bass but quite a bit less mid-bass performance than the AV15X sub). On the other hand, the LMS drivers are different animals, probably the best sub driver out there, but it's costly. I got mine for $650 w/shipping included, not bad, no? Anyways, I would think with the same power applied in my PR enclosure, say 1,000watts, the LMS should give me as much mid-bass as the AV15X driver with more SPL in the low bass which is something I need in my big room. Of course, while the AV15X driver would be reaching its limit with 1,000watts in my enclosure, I could feed the LMS driver 2,000watts easy, for another 3db gain.
I do want to see Illka give the 21" Maelstrom a test to see how it compares to the LMS, but the shipping is crazy. A ported LMS will be insane even outdoors. You really should get a good amp for it though. An EP2500 and a DCX are the two devices I'd want for any LMS sub. Cost always snags my projects though so I understand that element.
 

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Just FYI, here are the TSP's for the 2100 pr:


Thiele Small parameters:
Fs (Hz) 3.66
Qms 85
VAS (ltrs) 1840
Mms (g) 2100
Cms (mm/N) .9
Sd (cm²) 1200
Xmax (in) 3" p-p

WinISD calculates the QMS as 4.118 for the driver (not sure how close this is to the published figure).

Spanish, have you got any experience modelling enclosures, if so, then you can easily see for yourself the effects more power will have on the pr's and the driver. You will need to monitor what the power does to the driver as well, just because the motor can handle the power doent mean the final designed subwoofer will be able to. Its entirely dependant on design, but I would be careful about upping the power.

FYI, I have just run a model based on your provided TSP's for the driver, in a 200 litre enclosure using 2 x 2100 pr's and 1000 watts. The driver reaches xmax at 12 hz, the cab tune is still 16hz and the pr's are fine at full power down to the 12hz as well. More power is probably going to push the pr's too far at lower frequencies, but it will allow more room for comfortable eq'ing. It will also likely mean the driver will be pushed to xmax more easily so you will need to be careful there. Personally, I think if you want to up the power you may have to redesign the enclosure to protect the driver and pr's, as 1300 watts is the maximum the prs will handle and that raises the xmax breach to 13 hz. No point in spending on more power if your not really going to be able to use it.
 

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Spanish68 bear with me here.

Parameters.

AP Ultra 15.JPG



Here is the simulation of your current 7 cu ft dual 18" PR, 1300w AV15X sub (Orange) versus the AP Ultra LMS 15 (Green) just dropped in with no changes. The AV15X is about 3-4db more sensitive. However look at the cone excursion on 1300w it's over xmech below tuning and close to the 32mm xmech above tune. The AP is nowhere close.

SPL raw
spl 1300w.JPG

PR excursion
pr xmax no hpf.JPG

Driver excursion
xmax no hpf.JPG



I added a 2nd order Butterworth HPF (which is what your Rane has) at 15hz to the simulation for both and it helped out a bit. Still the AV15X is about maxed out already in your current design.

SPL with 15hz 2nd order Butterworth HPF
spl 1300w hpf.JPG

PR excursion with HPF
pr xmax hpf.JPG

Driver excursion with HPF
xmax  hpf.JPG



Here is where the AP 15" could go. This is with 4000w on the LMS which I assure you that the driver will handle in bursts during normal use. Just look at the coil, the motor and all of the cooling built into the thing when you get it. The HPF is still in the chain but the PR excursion was a little out of hand with this much power so I added a small peq cut at 15.5hz of only 2db to cut the PR excursion down a hair.

SPL on 4kw. EQ settings listed.
AP 15 eq hpf 4kw.JPG

PR excursion with 4kw, HPF and PEQ
ap 15 pr x hpf eq 4kw.JPG

Driver excursion with 4kw, HPF and PEQ
AP 15 eq hpf 4kw x.JPG



Make of the data what you will. As you can see at least on paper the AV15 is much more efficient, so it will have stonger upper bass unless you provide the AP 15 with more power. 4KW amps are expensive ($650-800), so I can understand if you don't go that direction. Don't worry about the breaker if you do upgrade your amp as the majority of the extra power is for quick bursts which will not over tax the breaker, not full out sines. One cool thing about the AP is any bad noises that you hear will not be coming from the driver once set-up correctly.

You could try a different build with the LMS 15. How about a big tapped horn? :D
 

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Discussion Starter · #13 ·
Moonfly, I was worried that my sub design would not be able to take much more power than what I now have, but looking at the simulations that Ricci did, my fears were eased somewhat.

Ricci, thanks for all those detailed graphs, they are very helpful in my decision making. Like you mentioned, as good as the AV15X driver is for the money, it's hitting its limits on my enclosure. I had to dial my LT1300 amp's volume back on the gain to about 9 o'clock. I did several tests with heavy bass movies scenes at reference, in the 20hz to 40hz area, each driver calibrated with the speakers, and my TC3000 and CCS SDX 15" drivers did not bottom out, but my AV15X driver did bottom out a couple of times. For example, in the King Kong movie, when Kong jumps in to fight the last T-Rex, the AV sub bottomed (claking noise). It seems to me that its limited motor force but even more important, the only 23mm of xmax available hit the limit, like it showed in the graph, no? I tried something with more mid-bass (Transformers), at reference level, which was at 0 on my receiver's volume and the sub handle that very well along with music. The sub's SQ is excellent, it's HT is good but not to its SQ level for sure.

Having tested my amp, it looks to me that the amp's full power is unleashed at around the 12-1 o'clock on the volume. Having read Elemental Design forum at AVS confirmed my findings where several members mentioned the 12-1 o'clock on the volume gave their subs extra bass. I guess each plate amp is a little different but if I had to guess, my sub right now is probably getting around half of the LT1300 power, some 650watts.

Since the AP LMS is some 3db's less sensitive than the AV15X driver, I'm sure when the calibration is done with the speakers, the volume on my plate amp is probably going to be around the 12 o'clock area on the volume which in theory, it should give me close to the AV15X's mid bass response, no? Doubling the power of the amp results in 3db of gain. I will do some testing with both subs to see what the results are.

The peak at tuning is very small, only a couple of db's, it should not be a big deal but I might end up cutting it with my PE17, we'll see. Also, from the graphs, it seems to me that the PR's and the LMS driver will be within their performance limits on my enclosure with up to 4,000watts as the graphs showed, as long as the HPF is set around 15hz to limits excursion below that. I do hope the AP driver gives me as good SQ or better with more SPL down low compared to the AE driver, specially if I do decide to upgrade the power. Anyways, within my current sub design limits, with the LMS driver and enough power, I should be getting the last bit of performance out of my design, right?

I was looking at some pro amps and like the QSC amps. I don't have much shelf space and like the fact that they are small and light. I like the PLX3402 and 3602 versions which I think will provide me with enough power for a reasonable price, $600-$800 for a used one. My questions are, do they provide spec power? How noise are they?

Ricci, I hope you're right regarding the breaker handling that extra power. I'm sure if I do get the QSC amp, after using it, I'll be able to tell if the breaker will need to be upgraded. If I do decide to upgrade it, I might just go with a 30amp version, it should provide me enough headroom, specially if I upgrade my AV gear.

As for a tapped horn design sub, not a chance. I already hit the size limit with my current sub design and due to space issues, only one sub. Also, there's the WAF factor. At least she did not have any issues with my current PR's sub.

Finally, I do like the ultra flat response the LMS driver has on the graph.
 

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The peak at tuning is very small, only a couple of db's, it should not be a big deal but I might end up cutting it with my PE17, we'll see. Also, from the graphs, it seems to me that the PR's and the LMS driver will be within their performance limits on my enclosure with up to 4,000watts as the graphs showed, as long as the HPF is set around 15hz to limits excursion below that. I do hope the AP driver gives me as good SQ or better with more SPL down low compared to the AE driver, specially if I do decide to upgrade the power. Anyways, within my current sub design limits, with the LMS driver and enough power, I should be getting the last bit of performance out of my design, right?.
Correct. The peak is small at the tune but in the sim above I put a 2db cut at the tune 15.5hz to keep the PR's workload down a bit at full power. Should be fine. Don't worry that driver will eat everything that your LT1300 has and ask for seconds. Trust me.

I was looking at some pro amps and like the QSC amps. I don't have much shelf space and like the fact that they are small and light. I like the PLX3402 and 3602 versions which I think will provide me with enough power for a reasonable price, $600-$800 for a used one. My questions are, do they provide spec power? How noise are they?.
QSC is good. Their service is great and they generally meet their specs. Where do you think Behringer stole the EP series from? :foottap: The 3402 or 3602 would be just about perfect. If you check around on the classifieds on prosoundweb you can occasionally snag one for about $600 used. Other amps worth looking at would be a Crown XS1200, or possibly the Yamaha P7000S. The fans are noticeable on any of these so keep that in mind.

Ricci, I hope you're right regarding the breaker handling that extra power. I'm sure if I do get the QSC amp, after using it, I'll be able to tell if the breaker will need to be upgraded. If I do decide to upgrade it, I might just go with a 30amp version, it should provide me enough headroom, specially if I upgrade my AV gear.
I think it will be fine. How often do you have your sub cranking for all it's worth? You won't be running it that hard usually. The power is there for quick peaks and headroom.

One last thing. Pics of the driver when you get it! :D
 

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Discussion Starter · #15 ·
Ricci, I think you're right, the LMS 15" driver is going to ask for more than what the LT1300 amp can offer. I just saw (it ended already) the Yamaha P7000S for $500 used in nice condition at Ebay, not bad for 3,200watts of power. I did not buy it since I'm king of worried about that fan noise on these amps. The fan can be changed for a more silent one, but I wonder how much would that reduce the noise. That's one of the main reasons I was looking at a plate amp and the little shelf space I have available does not help either.

I realize the big plate amp that Funky Waves might bring out soon is only rated at 2,400watts rms at 4ohm but it has peak power of 4,000watts which is what your model simulations look like with the AP driver. They are in the testing stages right now of that amp and should have an answer sometime next week on its performance. If there's enough demand, they say they will sell it to the public (DIY's). All I would have to do is expand the cutout of my current LT1300 amp opening some 1/2"-1" all around with a jigsaw (from the dimensions given) and place/plug the next amp right in. Very convenient and practical, no?
 

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Chris(Wmax) said the fans on the Yamaha's rarely come on so if fan noise is an issue I'd look at it.
I'm using a p7000s for my mains and the fan has yet to come on. It has a light load right now, but soon it will be powering something in the TC Sounds line.

Quote from the p7000s manual:
The fans do not come on at initial power-on, but will switch on
automatically when the temperature of the heat sink rises above
50°C (122°F). The fan speed will then vary automatically as
the temperature changes.
 

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Discussion Starter · #18 ·
Interesting read regarding the Yamaha P7000S fan. I guess the fan will turn on when the amp it's being pushed hard. I guess the harder the amp is pushed (the hotter it gets) the faster the fan will go. If pushed somewhat hard, maybe the fan is on, but at a slower speed which will cause less fan noise. Maybe those movies with lots of low bass at a loud volume will be the only time you can hear the fan run? Are amps such as QSC PLX 3402, 3406 and this Yamaha amp similar with regards to fan noise? Which one of these amps or some other compact amps has the best value/features/reliability for the price? Thanks.
 

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Discussion Starter · #19 ·
Finally, the wait is over, my AP Ultra LMS 15" driver arrived! It came in two boxes, with the basket in one and the magnet in another. Ricci, you're right, this is a quality driver all around. I work out, but let me tell you something, that magnet is heavy! Makes my previous TC3000 15" driver look like a toy!

Ricci, the back of the magnet has a little rust on it, is there any way to clean that up? Also, how do you put the basket and the magnet together? The top of the magnet has six screws on it, what's the purpose? Also, do you just line up the basket with the magnet were the threads are and twist the basket in the magnet clockwise all the way? Is that it? What's the easiest way to mount this beast? Thanks.
 
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