i have just brought a kicker L7 solabaric it is the new silver type and it is a dual 2 ohm voice coil. I will be running it of a lanzar 1200D at 1 ohm so it will be roughly geting about 1200rms could some one suggest a size for a sealed box that would have good sound quality and still go pretty loud
thanks in advance
John

42 litres works nice for a good all round performance, a bit more up to 56 litres, for more low stuff, with a little loss of punch.

With that much power, use a subsonic filter 26Hz-ish even in a sealed box (especially the larger one), it will excursion-limit low down.

Critter,

I agree with your suggestion, that you get nice SQ and bass response from those size boxes, but does power handling/cone excursion become an issue at these sizes.

I think subwayboy is talking about delivering up to 1200WRMS to the sub. At 42 litres the sub has a restricted power handling of ~600WRMS and the 52 litres leaves you with ~450WRMS. Correct me if I am wrong, but this was all to the best of my knowledge.

In addition to the above my calculations show that the sub in the mentioned boxes hits XMAX from ~60Hz and below with 1200WRMS.

Please correct me if I have made any errors, but Ithought it might be something to be aware of. I have heard these subs in 1 cu.ft boxes (28 Lt) and the hit strong, loud and accurately. They will not reach XMAX with 1200WRMS but you loose a bit of low down bass response.

The best way would be to experiment as I am at the moment. I am currently running the S12 in a 42Lt box, and am quite pleased, although the 28Lt was punchier, but less musical.

Sorry for the long post.

Points are well-made, silviawa.

Which is why I suggest running a sub-sonic filter to restricy excursion at the very bottom end.
Halve the frequency, you double the excursion....

In smaller enclosures, the system Q gets highish which explains why it hits well but gets a bit "one-note" in the bass.

Playing music, as opposed to a tone, the L7s will play fine with the shorter bursts of power even when there is a lot.
1200 watts is 3dB up on 600 watts and 600 watts will be LOUD!!!!

For a burp say at 55 hz, whatever, the L7 should be fairly OK even at full power so long as the amp is not clipped.

hey could someone clear up if the subsonic filter is already on my amp or do i need to buy it seperatly. if so how much are these and is there any trick to installing them. Is it also being suggested that i dont run the whole 1200 rms to the sub for daily driving becasue i would rather keep the 1200 rms for daily driving but just have the gains turned down and then when in a comp turn the gains back up to peak performance

Effectively taking into account what Critter and I have mentioned, running your subsonic filter on the amp will save your sub from punishing frequencies and excursion. If you were to detune your system for daily driving it would not have a problem in the boxes mentioned. Either do this through the deck, amp or external amp controller.

Then if you want to compete in SPL or just show people some power, a burp above 50Hz or so at full power should not do any damage, but be careful. At most as mentioned by Critter the difference from 1200W to 600W would be -3dB. Not all that much when you should be pulling mid to high 130's at least with 600W. Just be wary of distortion.

Hope I haven't confused you.

Damo

The amp's manual will tell you if it has a subsonic filter.

Some do, some don't (mine does )

If it doesn't, there are plenty around from a variety of brands and they don't cost NEARLY as much as a cooked L7.....

so i am a little confused can some one clear up what has been said above. what i think is the best option so far is to have the box to optimal daily driving specs while running the sub with the gains turned down and when i want to go loud just turn the gains up ( with in reason) have i uderstood or am i way of the mark??

The previous post by Critter was saying to check if your amp has a subsonic filter, if so turn it on, no matter what. If it doesn't have a subsonic filter, go and buy one as it will cost you less than a fried L7.

As for the question about the tuning of your sub detune the gains on the amp for daily use, you will hear the sub distorting when it gets to XMAX. Wind it back slightly from there just in case. Then if you want to do burps you should be able to wind the gains up but only if you are running frequencies above 50Hz or so.

Just tune it up and listen for distortion, always in every situation listen for distortion. That is the limit of the sub. No distortion and subsonic filter and the L7 will serve you long and proud.

ok i think i understand it now all i do is need to make my box

Why are u going with the sealed box?

I have heard critters ported L7, and it rocks

buy another one and mount one in each door

1) i heared teh 02 L7 are better in a sealed box
2) dont realy know how to make a ported box properly

Actually dual 4s are "more better" in sealed boxes (higher Q)
Dual 2s are "each way"
As DrEvil says, the dual is superb ported loooow in a well-built enclosure.

that of course doesn't make sense.

if the gains are 'turned down', then you are effectively capping the maximum power the amp can produce even with the volume setting up to max.

however, there is a thing called the volume control.

at low volume settings, the amp of course doesn't produce much power. tune the gains properly, and you can still yield 1200WRMS at full volume setting for when you want it. but for normal daily listening, do what most of us do and not drive around with the volume setting on 100%!

but more seriously, you may find that the gains need to be trimmed down anyway if the subbass is overpowering the front stage. i've had to trim mine down, which effectively means at full volume, the front stage utilises maximum amp power, but the subamp is capped to less than that so as to provide nice spectral balance.

good luck