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Discussion Starter · #1 · (Edited)
I have decided to go DIY and build two LLT sonotubes powered by 18" drivers. I won't be ready to begin the build until late this year or early next, and so I have lots of time to plan and make sure I get everything as right as I can make it.

Important considerations:
I am in the US Air Force, currently living in Germany. Therefore...

A) Any amplifier I get MUST be dual voltage (110/220V 50/60Hz - so I can use it when I move back to the states)
B) Anything I order from the US MUST have a shipped weight under 70lbs. (USPS will not ship anything over 70lbs, and as far as international FedEx... :spend: )

So, here are my preliminary thoughts...

SoundSplinter RL-P18 or Maelstrom X 18 (if either of these drivers ever become available by the time I am ready to build)
Power: Crown XTi 2000, 2ch mono (not bridged)
Box: Sonotube (or whatever Sonotube equivalent I can acquire in Germany)
Volume: 650L
Port: 8" port, 30/35" (MaelX/SS RL-P18) long, 50mm flare
Tune: 12/12.8Hz (MaelX/SS RL-P18)
Highpass: Signal Chain
Room: 2000cu/ft sealed
Processor: UPA-1 or Yamaha RX-V1900 (both dual voltage)

So, before we start literally talking about nuts and bolts (hurricane, T, woohoo!), how is my planned equipment looking so far?

I would like to be able to play up to reference. Sure, I'll probably be listening at -10 or so most of the time. But I want to be able to go to reference for those times I want to demo. And I want to do so with the subs going BOOM, not CRACK! I've seen War of the Worlds (but not on a super sub system), and don't really care for it. But I'm sure that somewhere in the future, I'll come across a movie with a similar "incident", and I want to make sure I don't blow the subs if I happen to demo such a scene at reference.

Speaking of not killing the drivers, I understand that an LLT does not require a high pass. Of course, when I model, I see excursion going way past the redline. I know that the signal chain is going to have a rolloff starting somewhere around 10Hz, but I like warm fuzzy feelings. As such, which highpass filter can I insert into the model (not into the finished product, just the WinISD model) which would give me an idea of how my signal chain will attenuate the single digit realm?

Okay, here are my models, available to be nit-piced, scrutinized, and adjusted!

One thing to note with regards to these models is that I set the signal level to give me an output of 112db at 30Hz. I did this because I figure having two of these working together will give me at least a 3db boost (getting me to 115b reference). And I used 30Hz because I figure in my room, gain should kick in somewhere around there, so it will boost everything below (ideally).









Recommendations?

Thanks!
 

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Discussion Starter · #2 · (Edited)
Looks like I need one more post to get pictures to display.

One thing I forgot to mention above - this will almost be my first DIY build. For my first build, I'm going to copy the Klipsch Driver in a Sonotube build as I have the exact driver, and a bad power supply in my RSW-12D. So at least I'll have some experience (mistakes?) under my belt!

Edit: There are pictures above... hopefully they will appear within an hour...
 

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Discussion Starter · #4 ·
I set the signal level to give me an output of 112db at 30Hz. I did this because I figure having two of these working together will give me at least a 3db boost (up to 6db if HSU Research's ULS-15 page is accurate), which will get me to 115db reference. And I used 30Hz because I figure in my room, gain should kick in somewhere around there, so it will boost everything below (ideally).

For the MalX, 410W is a pretty good number, in my mind, because it gives me 3db of headroom. With the RL-P18, it's higher sensitivity gives me even more headroom, requiring only 290WPC to achieve 115db.

Guess I should have mentioned this is for a Home Theater build. Also, I plan to try running a 40-50Hz cutoff. If all goes as planned, I'm going to buy a pair Klipsch RF-7s, and associated speakers, which are rated down to about 30Hz.
 

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forget the 18" malx as its been taken out off production because off issues. Sorry for giving bad news but you may be able to still source one from the european distributor but Kevin isn't selling them personally.

I don't think the soundsplinters will be available either for a while.

An alternative is the FI Q18 which is a great driver and can be sourced in the UK from Blade Ice.

It does almost seem a waste throwing just 400 watts at a £500 driver like the malx!
 

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Discussion Starter · #6 ·
The MalX should hopefully be back by the time I am ready to build late this year, or early next. I'm familiar with the issues, as I read posts from the owner over in the AVS forum. Somebody over there built 4 sealed enclosures each using 2 MalX 18", but what happened was a QC issue with the buildhouse resulted in the shorting rings not being sufficiently glued. This caused them to fall off in the motor, rendering the driver useless. This was only on the latest run of the MalX, and the owner is looking for a new build house as he has had problems with the current build house in the past. So it wasn't an issue with the MalX 18 per se, it was an issue with the builder not doing their job properly. Hopefully by 2012 we'll see them back again.

As for the guy making the 4 sealed enclosures with 2 18" drivers each, he ended up modifying them and installing LMS-5400s at twice the cost. But as I understand, the 5400s aren't a good LLT match. That and they are too heavy to ship to an APO, whereas both the other drivers can be shipped to an APO.

Then there's the issues SoundSplinter has come up with, what with their buildhouse filing for bankruptcy. The owner of SoundSplinter was told that late summer he should have the latest run of drivers, but he isn't holding out much hope for that. We'll see.

I'll take a second look at the Fi18. I think I passed it over because their site seemed a bit confusing, as I'm not sure exactly which customization options I really need on an 18" driver. What would you recommend?

Fi Q18
Ohm (assuming dual 2, wired in series)
Cooling: no/yes
P Chamfer: no/yes
High QTS: no/yes (I think I read SteveC saying a high QTS is desirable for LLT)
Spider: no/yes
I Heat Ring: no/yes
 

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Discussion Starter · #7 ·
Why is your input power so low? The amp is 800 watts per channel.
DOH! :doh: In spite of my last response, I just realized something... that SPL figure it's giving me is a 1M figure! (I believe) So you're right, I do need to re-calculate for higher levels. 2 meters at the minimum, which means I am 3db low.
 

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Give [email protected] an email and he will sort you out much better. He is a very helpful guy. He even answers his emails at 11pm at night. Top guy. They are bringing out blueprint drivers which should be very similar to the malx in terms off power, excursion etc or may be even more but we are still to find out what the parameters are.

I feel for the guy on the avsforum. I watched his thread from start to finish. He has 8 LMS 5400 drivers with a mammoth off power. He did some distortion tests in REW and at 123db at 10hz he measured only about 2%. That is very impressive. I don't know where this guy gets his money from but he isn't short off it that's for sure.

Yep the LMS drivers require small boxes but with crazy amounts off power.

Good luck.

cheers

Graham
 

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Discussion Starter · #9 ·
Okay, I revised my modeling.





A note on port velocity - notice the "Flare It" program has no allowance for seating position and content. If I add that in, Flare It tells me that I am below the chuffing and core limitations.

Obviously my power requirements have changed (520W RL-P18, 920W MalX). I looked around the Crown amplifiers on Parts Express, and I need a recommendation...

2X XTi1000, each running bridged mono (1400W)
2X XLS1500, each running bridged mono (1550W)
2X XLS1000, each running bridged mono (1100W - only if the driver I choose requires less than 600W)

According to the Crown website, the XTi series has a proportional speed fan. Whats the word on fan noise with these units? If the XTi is generally quiet, I'll spend the extra money. But if they are about the same, I'll get the XLS, save some money, and do a fan mod.

I also read some controversy about the XTi's viability as a subwoofer amp. Something about sine wave testing vs burst testing. What's the final verdict? And if I run REW sweeps with this, is my <20Hz frequency response going to be off? I'd hate to built two LLTs and cripple them with an amp that by some accounts is highpassed at 20Hz...

Speaking of highpassing, these revised graphs show excursion through the roof! What's the word on which filter to use in order to model a signal chain's low frequency rolloff? Cone excursion 60mm past Xmax doesn't give me a warm fuzzy feeling...
 
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