I have decided I want to build my own sub

[WmAx]

That really is a use of extreme brute force and not a very elegant design. It certainly does not fit my design philosophy, but I guess to each his own.

Perhaps, but the LMS drivers are the highest fidelity/lowest distortion drivers known to exist. They consume incredible level of power and produce incredible, super low distortion output. The motors in the LMS have variable density voice coils - as the VC moves farther and magnet force varies, the variable VC density comes into play and compensates. The result is the flattest BL vs. excursion curve of any type of driver in existence. +/- 38 mm on the drivers above reads as a nearly perfectly flat BL line through the entire range of movement. The drivers have massive venting system and exhibit very little compression even with 2000 watts being fed to them.

TLS Guy, here is 3rd party measurement of an 18" LMS driver, fed with 3600 watts, and 13dB Gain applied to the low end in a small 100 Liter sealed box. Note the compression is almost non existant until the very highest power levels(!), and note the very very low distortion despite the massive power being input at 20-30Hz range with massive gain added to compensate for the tiny sealed box:

http://www.hometheatershack.com/forums/subwoofer-tests-archived/8154-diy-tc-sounds-lms-5400-18-sealed-100l-lt.html

-Chris

 

[TLS Guy]

Perhaps, but the LMS drivers are the highest fidelity/lowest distortion drivers known to exist. They consume incredible level of power and produce incredible, super low distortion output. The motors in the LMS have variable density voice coils - as the VC moves farther and magnet force varies, the variable VC density comes into play and compensates. The result is the flattest BL vs. excursion curve of any type of driver in existence. +/- 38 mm on the drivers above reads as a nearly perfectly flat BL line through the entire range of movement. The drivers have massive venting system and exhibit very little compression even with 2000 watts being fed to them.

TLS Guy, here is 3rd party measurement of an 18" LMS driver, fed with 3600 watts, and 13dB Gain applied to the low end in a small 100 Liter sealed box. Note the compression is almost non existant until the very highest power levels(!), and note the very very low distortion despite the massive power being input at 20-30Hz range with massive gain added to compensate for the tiny sealed box:

http://www.hometheatershack.com/forums/subwoofer-tests-archived/8154-diy-tc-sounds-lms-5400-18-sealed-100l-lt.html

-Chris

I agree they are nice results, however expending 3600 watts to produce 108db spl from an 18" driver fails to impress me. May be I'm too old and reactionary, but not only does it not impress me, but I think it is a bone headed solution.

 

[WmAx]

I agree they are nice results, however expending 3600 watts to produce 108db spl from an 18" driver fails to impress me. May be I'm too old and reactionary, but not only does it not impress me, but I think it is a bone headed solution.

That is of course, anechoic (1M) / field (2M) results. I don't know of any other driver at any cost that even come close to these results. In room, that is at least 118-120dB at 20Hz, from a single driver in a very undersized sealed box. I fail to see how this can not impress, since distortion is still relatively low, and very little power compression is occuring. This is simply demonstrating the driver is in a league of it's own when it comes to handling massive excursion, thermal capacity and motor linearity.

Put the driver in a more ideal enclosure, and it will easily produce far more SPL in the bottom octave. You know that a tiny sealed box results in a great deal of loss to SPL at the lowest octave. This type of arrangement is very important/useful in applications where the sub must have the smallest possible size yet retain as much performance as possible.

Here is the driver in a box using massive passive radiators:
http://www.hometheatershack.com/forums/subwoofer-tests-archived/8156-diy-tc-sounds-lms-5400-18-2x18-page-ranking-200l.html

Output, anechoic (1M), is about 116-118db for most of the range. You will come to around 130dB in an average closed room with this single driver, in an ideal cabinet type/design. Distortion/compression remains incredibly low.

-Chris

 

[lsiberian]

I agree they are nice results, however expending 3600 watts to produce 108db spl from an 18" driver fails to impress me. May be I'm too old and reactionary, but not only does it not impress me, but I think it is a bone headed solution.

I tend to agree. I'd much prefer an efficient sub that is great over a great sub that's inefficient. That being said I don't see many folks ever using 120 db out of a sub over extended peaks.

 

[WmAx]

I tend to agree. I'd much prefer an efficient sub that is great over a great sub that's inefficient. That being said I don't see many folks ever using 120 db out of a sub over extended peaks.

I'de like to see you find a sub in the same league as the LMS that is very efficient. But as you see from the ported/pr test results, you get far more SPL for your watts in the normal type of cabinet. I did specifically show the results of the driver in a very small sealed box with electronic correction for a reason, and it's not exactly an unknown that any under-sized box application with a high level of boost correction requires a huge amount of power.

-Chris

 

[BigSkreen]

In general what does the additions of a passive radiator do to a box? Also it seems that you have to buy specific passive radiators tuned to a box.

 

[TLS Guy]

In general what does the additions of a passive radiator do to a box? Also it seems that you have to buy specific passive radiators tuned to a box.

It is just another way of making a tuned box with the radiator replacing the port, but for the home builder much more difficult and uncertain. I steer people away from doing that, unless you want to make a sub like the Peerless one, where there is matching woofer and ABR. The other problem with passive radiators is that the roll off is even steeper than 24 db of a ported box.

 

[Warpdrv]

I'de like to see you find a sub in the same league as the LMS that is very efficient. But as you see from the ported/pr test results, you get far more SPL for your watts in the normal type of cabinet. I did specifically show the results of the driver in a very small sealed box with electronic correction for a reason, and it's not exactly an unknown that any under-sized box application with a high level of boost correction requires a huge amount of power.
-Chris

Are we sure those Rls's aren't rebadged Tc-sounds Axis drivers if I recall correctly, correct me if I'm wrong.
I see they have the 4 stack of magnets, but that is def an axis basket and a different cone. ???????


The benefits of the LMS's are its extreme linearity abilities in a small box. And the drawbacks are that you need big power to get what you want out of them. They are expensive - but they are by far the best engineered, heavy duty drivers - and the punishment they can take has almost no rival... just brutal and IMO worth the price of the entrance fee.

You can get big output from a lesser driver in a ported enclosure with less power, but not everyone wants big huge ported box in their homes, I certainly didn't.

I have come across a very nice PR box that John from Acoustic Elegance brought to my house for a subwoofer shootout, it was an amazing performer. 15" driver with dual 18" PR's, the output was staggering driven by roughly 1000w (EP2500 bridged at 1/2 gain or so) tuned to about 16hz I believe. Box size 2'x2'. Same as my LMS's sealed.

I so far have 2 18" LMS's in my great room and they are the best drivers I have come across to date, waiting on my 3rd, and I'll be done building for good. Each are powered with 4000w Crest 8002's bridged, the amount of super clean effortless bass I get from 2 of them has no rival.

 

[WmAx]

Are we sure those Rls's aren't rebadged Tc-sounds Axis drivers if I recall correctly, correct me if I'm wrong.
I see they have the 4 stack of magnets, but that is def an axis basket and a different cone. ???????

There is no question that the RL-S is using LMS motors. Sound Splinter may have specified different baskets - but they RL-S are LMS drivers. SS even specified that the 'variable density' coil motor is used - this is LMS technology. You can read about this when they first came out in this post by Sound Splinter. TC Sounds designed and builds the drivers for SS. The 15" Sound Splinter LMS drivers are rated at 2000 Watts RMS, and have a rated 38mm one way linear excursion. I'm sure in real world use, they can take far more then 2000 watts with actual music program.

-Chris

 

[Warpdrv]

Nice, never saw that before... its a good read...

 

[BigSkreen]

I have my DCX and amp. I am working on getting the driver. At the moment I also using sketchup to build a box with enough bracing while retaining a 4.5 cubic ft box. I am modeling the material to be .75" thick. I haven't decided between MDF and plywood yet.

 

[BigSkreen]

Here is my first swipe at the model. Hopefully the link works. I appreciate any comments. Also if anyone has a CNC machine that I can just drop some wood in and pull this out that would be great.

http://sketchup.google.com/3dwarehouse/details?mid=7f0d9777db4397965c2d7065c79d7033

It is essentially an 18"x18"x26" inside dimensions. With 2 braces. I subtracted the volume of the sub and the volume of the braces. It should come out to close to 4.5 cubic feet.

 

[lsiberian]

That is of course, anechoic (1M) / field (2M) results. I don't know of any other driver at any cost that even come close to these results. In room, that is at least 118-120dB at 20Hz, from a single driver in a very undersized sealed box. I fail to see how this can not impress, since distortion is still relatively low, and very little power compression is occuring. This is simply demonstrating the driver is in a league of it's own when it comes to handling massive excursion, thermal capacity and motor linearity.

Put the driver in a more ideal enclosure, and it will easily produce far more SPL in the bottom octave. You know that a tiny sealed box results in a great deal of loss to SPL at the lowest octave. This type of arrangement is very important/useful in applications where the sub must have the smallest possible size yet retain as much performance as possible.

Here is the driver in a box using massive passive radiators:
http://www.hometheatershack.com/forums/subwoofer-tests-archived/8156-diy-tc-sounds-lms-5400-18-2x18-page-ranking-200l.html

Output, anechoic (1M), is about 116-118db for most of the range. You will come to around 130dB in an average closed room with this single driver, in an ideal cabinet type/design. Distortion/compression remains incredibly low.

-Chris

That is insane. The distortion is unbelievably low. It would seem like a PR would be the only way to pull off a port on this monster sub. Due to the rear port air velocity likely being insane.

 

[lsiberian]

I have my DCX and amp. I am working on getting the driver. At the moment I also using sketchup to build a box with enough bracing while retaining a 4.5 cubic ft box. I am modeling the material to be .75" thick. I haven't decided between MDF and plywood yet.

I'd do plywood unless you have a fork lift. For bracing simply use Oak 1" x 2" or 1" x 3"

MDF is very heavy and would make this sub very heavy. Ply also holds a screw better.

 

[BigSkreen]

I'd do plywood unless you have a fork lift. For bracing simply use Oak 1" x 2" or 1" x 3"

You know I don't think the WAF is very high on a forklift. I think I'll stick to plywood. I might have a lead on a good lumber yard.

 

[BigSkreen]

Where can I find a good RCA to XLR cable to connect the DCX2496 to my AVR?

 

[Warpdrv]

http://lmgtfy.com/?q=rca+to+xlr+adapter

 

[KEW]

Where can I find a good RCA to XLR cable to connect the DCX2496 to my AVR?

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10244&cs_id=1024404&p_id=4776&seq=1&format=2

I really like how pliable these cables are compared to Monoprice's standard RCA to RCA cables!

 

[BigSkreen]

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10244&cs_id=1024404&p_id=4776&seq=1&format=2

I really like how pliable these cables are compared to Monoprice's standard RCA to RCA cables!

That is exactly what I was looking for. I kept finding some that were the wrong gender and for some reason totally spaced on monoprice. Also all the other ones I found were like 20 ft.

 

[jinjuku]

http://lmgtfy.com/?q=rca+to+xlr+adapter

Your are now my most favorite person in the world. I am shocked I didn't hear about this sooner.