DIY TC Sounds LMS-5400 18" sealed 100L

[Ilkka]

Manufacturer: DIY
Provided by: Ilkka
Manufacturer link: -
Price: -

Please contact if you would like to have the same kind of subwoofer (with better cabinet and numerous finish options) being built for you.

Manufacturer specs:
• Woofer: TC Sounds LMS-5400 18” (DVC 2x2 ohm)
• Amplifier: Crown CE4000 (~3600 W @ 4 ohm bridged per amp)
• Enclosure: 100 liters, 21mm (15-ply) baltic birch all around, 42mm front baffle, well braced, total weight with woofer around 60 kg / 132 lbs
• Signal processing: Behringer DCX2496

Configuration as tested:
Phase: 0 degrees
Crossover: 30 Hz / 120 Hz / Bypassed
EQ: No
Subsonic filter: No
Orientation: Woofer facing the mic

[Ilkka]

+/- 3 dB points: 14 Hz - 44 Hz (crossover min)

+/- 3 dB points: 25.8 Hz - 130 Hz (crossover max)

[Ilkka]

[Ilkka]

[ec114]

http://personal.inet.fi/private/zipm...l thd comp.png

Thanks, as usual, for all the great info, Ilkka. Would just like to point out that, according to Linkwitz's closed-box spreadsheet, 100l is good for something like 6% air-spring distortion at the LMS-5400's maximum displacement, which, if true, makes this result even more spectacular. Not sure if this chart is really for constant 110dB SPL at each frequency, or if it's a plot of the distortion along the "110dB SPL" curve from the Maximum Output Level chart, but either way, the box should be doing some damage...

[Ilkka]

ec114 wrote:

http://personal.inet.fi/private/zipm...l thd comp.png

Thanks, as usual, for all the great info, Ilkka. Would just like to point out that, according to Linkwitz's closed-box spreadsheet, 100l is good for something like 7% air-spring distortion at the LMS-5400's maximum displacement, which, if true, makes this result even more spectacular. Not sure if this chart is really for constant 110dB SPL at each frequency, or if it's a plot of the distortion along the "110dB SPL" curve from the Maximum Output Level chart, but either way, the box should be doing some damage...

It's a plot of the harmonic distortion by component along the "110 dB SPL" curve so for example at 20 Hz the SPL is ~100 dB. That means around 19 mm of excursion which translates to ~2.9% of air spring distortion (mostly 2nd harmonic) per Linkwitz. Of course that's just the theory, at least I haven't seen any real measurements on this subject.

[ec114]

Ilkka wrote:

It's a plot of the harmonic distortion by component along the "110 dB SPL" curve so for example at 20 Hz the SPL is ~100 dB. That means around 19 mm of excursion which translates to ~2.9% of air spring distortion (mostly 2nd harmonic) per Linkwitz. Of course that's just the theory, at least I haven't seen any real measurements on this subject.

Doh! I guess the as-tested maximum output of 106dB@20Hz would rule out 110dB there. Not thinking so well; anyway, 2.9% due to box makes the driver look even better, and a larger box more attractive technically, if not aesthetically...