Finnish LLT projects

**Ilkka** · **11-23-06, 08:09 PM**

I thought to show you some first Finnish LLT projects. I helped to desing both of them.

Both are as follows:
~265 liters net
~16 Hz (simulated)
TC-2000 15" SVC
6" aeroport
24", 1/2" (!) sonotube
3x19 mm end caps
Very stout and definitely airtight.
The other one uses a BK Electronics 500W plate amp, and the other one a ButtKicker 1100W amp.

The first one

The second one (click on "seuraava sivu" in order to get to the next page)

Both owners are extremely pleased with the outcome. Very good sound quality with music and enough shaking with movies. They both live quite near to me, so I think I'll pay them a visit in the near future. I'll take my measuring gear with me of course.

**Rodny Alvarez** · **11-23-06, 08:39 PM**

NICE!!!

**Sonnie** · **11-23-06, 11:23 PM**

Yes... very nice! I would really love to see some measurement data on these.

An LLT looks like something I might really enjoy piddling with. A lot less expensive than IB.

**Hakka** · **11-24-06, 12:39 AM**

Excellent work mate. What did you use to get the finish on the endcaps of the black one?

**terry j** · **11-24-06, 03:26 AM**

very nice stuff. must say I'm intrigued by the LLT. From what I can gather, IB is supposed to sound the best - and not many arguments ensue from a statement like that - and then LLT comes in behind that but ahead of the rest of the pack.

IB is totally out of the question architecturally for me, let alone cost of tons of drivers and amps, and besides that I reckon the sonotubes are actually the most attractive way to get a monster sub!

I particularly liked the first one aesthetically, if only because it got away from the 'everybody does black' look. Not that there is anything wrong with that!

excellent work

lots of love

terry

**Exocer** · **11-24-06, 08:11 AM**

Can't wait to see the LLT test results

Great stuff indeed

**Ilkka** · **11-24-06, 08:18 AM**

Quote:

Hakka wrote:

Excellent work mate. What did you use to get the finish on the endcaps of the black one?

I assume he used a standard black spray paint.

**Ilkka** · **11-24-06, 08:45 AM**

Quote:

Exocer wrote:

Can't wait to see the LLT test results

Great stuff indeed

Do realize that these will be simple in-room measurements (frequency response, tuning frequency and maybe THD). No GP data yet...

**Sonnie** · **11-24-06, 12:09 PM**

Quote:

Ilkka wrote:

Do realize that these will be simple in-room measurements (frequency response, tuning frequency and maybe THD). No GP data yet...

Those will still be interesting to see.

**---k---** · **11-24-06, 06:14 PM**

Quote:

terry j wrote:

(snip)
and then LLT comes in behind that but ahead of the rest of the pack.
(snip)
terry

A lot of people would argue with this.

**Ilkka** · **11-24-06, 07:44 PM**

Some info about the owner of the white sonosub.

He used to have 4 sealed 12" woofers in his car, so he was a little bit worried whether this new sub could provide the same kind of kick in the chest feeling. He actually started too think of building two sealed sonosubs using TC-1000 woofers. I said he should wait at least until this first one would be ready... Now that he got it done and running, he forgot those extra subs. He says he can't believe how tight and punchy this large ported sub is. Though now he has a new problem - his mains can't keep up with the sub.

**Hakka** · **11-24-06, 09:00 PM**

Quote:

Ilkka wrote:

He actually started too think of building two sealed sonosubs using TC-1000 woofers. I said he should wait at least until this first one would be ready... Now that he got it done and running, he forgot those extra subs.

I built 2, mainly because I could only get a 4 metre length of sonotube and a very large sheet of MDF. I connected one of them and it was obvious I didn't need the second one, but it does come in handy for getting a more even response across the seats in my symetrical room.

**terry j** · **11-25-06, 04:53 AM**

Ryan, could you expand on the statement " terry j wrote: View Post
(snip)
and then LLT comes in behind that but ahead of the rest of the pack.
(snip)
terry
A lot of people would argue with this.

I am certainly not arguing with you, I'm in learning mode.

What is it that some would argue with?

LOL

terry

**Josuah** · **11-25-06, 12:14 PM**

I rejected going LLT in favor of sealed, with IB not an option. For my design goals, namely flat in-room response to single-digits, the ported and passive radiator models didn't turn out very well. Particularly because of the port volume needed to be so large coupled with the rapidly increasing group delay. It would have been extremely difficult to build an enclosure with a port that was larger than the enclosure, so a passive radiator would be more feasible. But the group delay gets even worse with a PR. And it would be harder to find a PR that would provide the necessary mass to fit by itself on a sonotube endcap; I originally resigned myself to a box enclosure, but the calculated weight would have been like 200 pounds per unit, or something like that, for a PR design.

The trade off is I need to pump in much more power and the overall cost is increased, but I am going with sealed sonotubes now.

**SteveCallas** · **11-25-06, 01:37 PM**

Quote:

From what I can gather, IB is supposed to sound the best - and not many arguments ensue from a statement like that - and then LLT comes in behind that but ahead of the rest of the pack.

I'll continue to take flack for this, but do keep in mind that an IB will require multiple drivers to match the headroom of a single driver LLT.

Great stuff though. Taking the LLT global

**terry j** · **11-26-06, 04:34 AM**

Yeah Steve

had already worked that one out, need multiple drivers, and lots of amp power as well?? (adsmittedly watts are cheap nowadays )

I know you are Mr LLT, but have you ever heard an IB?? If so, how would you characterise the essential similarities and differences between the two??

Joshua, have you written up your sub anyplace, if so I'd love to be able to have a look. I will readily admit that I'm not technically 'savvy' enough to really follow your reasoning above, but can't you use eq on the LLT to get the same in room response as a sealed?? Presumably you came to your conclusions via a modelling program, which one did you use? Could your decision have been different if you'd modelled with different drivers?

a lot to learn eh!!

**Josuah** · **11-26-06, 01:33 PM**

I'm still in the processing of building the subs (someone tell me why it is so difficult to get an endcap to fit into a sonotube?!) and plan to write things up and post photos when it's done. Probably next weekend.

I use WinISD Pro (alpha) to do my modeling. I wish there was a decent Mac OS X program to do it, but doesn't seem to exist. My overall conclusion wouldn't depend a lot on the drivers, because all you'd be doing is moving the max SPL level up and down and moving the driver Fs left or right.

So I just modeled a 15" TC-2000 with two SA-PR15-1400 passive radiators. Maximum cone excursion is reached at 7Hz with 120W of power. So you see, applying a boost here would blow everything up. Again, ported won't work because the port volume is just too great for such a low tuning. Ported and PR designs fall off at 18dB/octave and 24dB/octave (IIRC) at the tuning frequency. The tuning frequency of the design I just modeled is 16.55Hz. I can use EQ cuts to flatten the response up to the tuning frequency (SPL at 30Hz is about 30dB greater than SPL at 7Hz), but I can't do anything to boost the low end.

Sealed designs roll off much more gradually, so I need more power but I can use EQ boosts to make it flat without sacrificing the higher frequencies. My sealed design, using two 15" drivers instead of a 15" driver and two 15" PRs, and boosting the low end, reaches maximum excursion at 7Hz with about 2200W of power, but is about 20dB stronger at 7Hz, and the high end is much closer to that point; e.g. SPL at 30Hz is about 10dB greater than SPL at 7Hz.

Also, I'm not talking about max SPL. Just the flatness of the SPL across the spectrum. Max SPL >20Hz is still greater with less watts with a ported or passive design.

As a side note, group delay is not so bad in the PR I just designed. Only a little worse than the sealed and probably negligible.

**terry j** · **11-26-06, 06:51 PM**

thanks Joshua

what I keep forgetting in all this is that probably this is primarily an HT forum, and most of you guys are into movies, hence the need (??!!??) for your subs to go that low.

Music only for me, movies I find booooooriiinng, so I only need to do a solid 20 hz. That should be a cakewalk after all the trailblazing you guys do!!

Just so I understand, you mention the port volume required at the frequencies you're talking about as 'just too great'. Does that mean to compensate by increasing the size of your tube it gets too big, or are you practically saying the port is HUGE and simply not practical. Again, from vague recall of the LLT philosophy, most are knida tuned around 15 hz or so, is yours different in being tuned much lower which then leads to the problems you've encountered??

We are all looking forward to the well documented pictorial post you will soon be giving us on your sub construction, along with full measured results!! ha ha

lots of love

terry

**terry j** · **11-26-06, 06:55 PM**

sorry Josh, just re-read your post, and see that you are tuning to 16.55 hz, so you're not tuning lower. Will have to re-read the LLT again to work out for myself why most can use an LLT and you can't, went and got myself all confused again!!

**Ilkka** · **11-26-06, 08:37 PM**

Guys,

My humble request. If you do not have anything to comment on the Finnish LLT projects, please start your own desing thread.

**---k---** · **11-27-06, 09:47 AM**

Ilkka,
I agree. I think the sealed v. ported is a differnt thread. I also think it has been played out already, so a little searching can be done to find out everyone's opinion. However, I don't think it is right to let go such sweeping claims as LLT sounds the best after a an IB. Obviously the poster of this is new and just repeated something he heard. If a few more new people start repeating this, with understanding all the tradeoffs it becomes a snowball of hype. XYZ has used this marketing method very effectively. Lets not be those guys.

**SteveCallas** · **11-27-06, 03:22 PM**

Agreed, claims of which sounds best can't be applied to alignments. Accuracy can, but not sound quality, as everyone has different preferences.

I actually like the look of the white one:

I would have kept the legs silver on the black one though, but different strokes for different folks.

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