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Old 8th January 2012, 01:06 AM   #511
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That is a very important thing to consider. I don't think I saw excursion go past that with my SS15s using ~600W with both 30Hz & 50Hz sinewaves & deep dubstep (HPF LR24 @ 32Hz +3-4dB EQ @ 30 & 40Hz). I'll readjust input power to match more realistic displacement numbers and get back to you gents.
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Old 8th January 2012, 02:24 AM   #512
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by CRESCENDO View Post
That is a very important thing to consider. I don't think I saw excursion go past that with my SS15s using ~600W with both 30Hz & 50Hz sinewaves & deep dubstep (HPF LR24 @ 32Hz +3-4dB EQ @ 30 & 40Hz). I'll readjust input power to match more realistic displacement numbers and get back to you gents.
Excursion is in the first place load related. The lower the low corner, the higher the excursion becomes (with the same power). The smaller the mouth the lower the SPL (efficiency of the system).

Also look at the point you need to EQ in realtion to excursion peaks. You don't want to EQ (adding gain) there where excursion max is. Also think of what Djk said, most energy is used between 40 and 60Hz (that also counts for most Dubstep tracks).
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Old 8th January 2012, 02:25 AM   #513
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The response will lower ~3dB, but the spl differences and freq responses remain the same in comparison. So, what I was getting at is that it looks like these 3015LFs will be fine in either of the enclosures mentioned, without sacrificing much LF at all + Erik won't need to spend a lot of time designing yet another enclosure and one wouldn't need to build another enclosure to accept the higher power, higher quality 18" driver(s). What are your thoughts?
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Old 8th January 2012, 03:38 AM   #514
Djim is offline Djim  Netherlands
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Go for Eric’s 'straight tube' with large horn mouth since it has the best balanced system for your drivers and I really like his symmetric (central) mouth setting. The highest sensitivity figure, the highest system efficiency and still provides decent low end extension. -3dB around 38hz in sim. This will be at cost of an earlier roll-off but the roll-off will be less steep.

Theoretically you should reach Xmax with 315W so with 600W max per cab you should be able to get everything out of that driver and stay within the safety zone as long you don't start "freakin' pumping" like some DJ's do.

The straight tube with small mouth is 2dB lower in efficiency between 40Hz and cross over point. With the small mouth theoretically you will reach Xmax with 259W so 600W is . At max SPL it will be 3dB lower where you need it, 40Hz to 60Hz. 2dB loss from smaller mouth size and 1dB because the excursion is higher in the smaller mouth version.

In other words, a larger mouth gains up to 3dB between 40Hz and 60Hz at the cost of an earlier (but more gentle) roll off.
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Old 8th January 2012, 09:33 AM   #515
epa is offline epa  Netherlands
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hi all
i did some simming,if you increase s5 area the cab volume increase with 50 ltrs (sim).
to compensate i have to reduce the the other area,s to get to the same cab volume.
also need to extend the horn path to get te excursion dip back 33 hz (single cab)
then i put more power in to get to the same excursion figure.
Click the image to open in full size.
we should consider that justen probaply uses them in 3's or 6 .
however there is still a debate on f3 extension vs multiple subs.:]
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Old 8th January 2012, 11:43 AM   #516
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Quote:
Originally Posted by Djim View Post
Also look at the point you need to EQ in realtion to excursion peaks. You don't want to EQ (adding gain) there where excursion max is.
Yes, I have a habit of checking this. It can definitely be a deal maker/breaker.


Quote:
Originally Posted by Djim View Post
Also think of what Djk said, most energy is used between 40 and 60Hz (that also counts for most Dubstep tracks).
True, but I need to keep in mind that many of the tracks we play have plenty of information at and below 30Hz to worry about.
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Old 8th January 2012, 11:44 AM   #517
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Erik, did you see post #509?
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Old 8th January 2012, 12:54 PM   #518
epa is offline epa  Netherlands
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overlooked post 509
yes for future consideration ,its posible.
but what wil you do with the 3015 in the future.
how long are you thinking wil that futere be .
why not use cheap underlayment 18 mm for the time being,and sell them as a whole cab in the future.
you might be suprised with the 3015 preformance with 6 wel tuned boxes.
just my 2 cents,
grtz erik
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Old 8th January 2012, 06:09 PM   #519
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by epa View Post
hi all
i did some simming,if you increase s5 area the cab volume increase with 50 ltrs (sim). to compensate i have to reduce the the other area,s to get to the same cab volume. also need to extend the horn path to get te excursion dip back 33 hz (single cab) then i put more power in to get to the same excursion figure.
we should consider that justen probaply uses them in 3's or 6 .
however there is still a debate on f3 extension vs multiple subs.:]
Hi Eric,

Indeed we should consider he uses them in stacks of 3 and power's them with 600W per cab! If you lower the excursion dip to 33Hz he will overpower them and more important, he will not get 128dB (average) per stack in reality. 8mm is about the max peak excursion (with severe dynamic compr.) a 3015lf has to offer.

The debate of stacks is about acoustic coupling which is something else. If you use Neo Dan's method, by positioning the cabs under a corner, you extend the path physically! by 0.6 It's the same as using an extender and that's why Dan's method does work.
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Old 8th January 2012, 11:29 PM   #520
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Quote:
Originally Posted by Djim View Post
Go for Ericís 'straight tube' with large horn mouth since it has the best balanced system for your drivers and I really like his symmetric (central) mouth setting.
His symmetrical version does seem to be the better of the two.


Quote:
Originally Posted by Djim View Post
as long you don't start "freakin' pumping" like some DJ's do.
"Freakin' pumping"? I'm unfamiliar with this term


Quote:
Originally Posted by Djim View Post
In other words, a larger mouth gains up to 3dB between 40Hz and 60Hz at the cost of an earlier (but more gentle) roll off.
I don't have your HR inputs to directly compare what I've been working with to your outcome. I did increase the mouth to 4000cm^2, but our traces are different (obviously).

Quote:
Originally Posted by epa View Post
but what wil you do with the 3015 in the future.
how long are you thinking wil that futere be .
why not use cheap underlayment 18 mm for the time being,and sell them as a whole cab in the future.
you might be suprised with the 3015 preformance with 6 wel tuned boxes.
just my 2 cents,
grtz erik
I could sell them, build more SS15s or use the straight pipes for a secondary system.

Future? Maybe March/April or a bit after. We'll see how things go.

I could definitely consider building w/aurauco 0.7" and selling the cabs. But, I may just keep them as a secondary system. Maybe for shows that have more than 1 room. Or for when the need calls for 2 different rentals, etc.

Looks like the symmetrical version is pulling ahead. The 3015LFs will probably be happier (less stressed), as well


Here are comparisons of 'Erik's straight pipe mod w/3015LF' (5 posts back) and his 'tbx box loaded w/3015LF' both @ 8mm. I also compared the '3015LF-loaded tbx box' to the straight pipe (S1, 2, 3 & 4 = 1500; S5 = 4000cm^2) and used Erik's initial L/par settings for the straight pipe.
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