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Discussion Starter #181
Sonnie,

I like what Audyssey does to the other speakers in giving me a much fuller sound. I will try re running Audyssey again but reduce the gain on the EP4000. Would that help do you think.

cheers


Graham
 

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Anymore progress?

I should have read your thread before I started mine.

Awesome build.

Would love to see some video footage of sub 10hz.:D
 

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Discussion Starter #183
Thanks matey,

I don't have a decent video camera at the mo but my missus is looking to the the new sony 720p HD mobile so hopefully that will be good enough.

cheers

Graham
 

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The wifey has a Sony HDR-XR100 that is 1080p recording which is pretty nice. Someday when I start to build some of these subs I will try and use her camera.

That being said does a speaker or does your subs reach there xmax when playing the really low noted like the 7hz?

When I have seen graphs it seems like sometimes the speaker will hit xmax but not at the lowest freq. that it can reach.
 

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Discussion Starter #185
Hi matey,

I haven't done extensive tests, just ran some sinewaves. I know for certain I can run a 15hz sinewave at reference no probs and not alot of excursion. Need to try 14, 13, 12, 11 and 10. My winisd plot will max excursion at 11.5hz with full power of 1200 watts. I would say that, that is the EP4000's ratings and that is not true on the real world.

I will do some more tests over the weekend to see how it fairs but I can certainly run reference with Transformers 2 with the EP4000s gain on max and the onkyo on +1db. I am running 5db hot too.

I will let you know how I get on.

cheers

Graham
 

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Dont forget to test 5, 4, 3, 2, 1 and 0hz. HAHAHAHA
 

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Discussion Starter #187
I tried 1hz. Not a dicky bird. I guess I would still get a movement on 5hz. How loud and safe that would be. According to winisd without a hpf engaged at 5hz at full power I am at 60mm excursion so I guess I am just over xmax going into xmech terrority. If I had a Reckhorn B2 I probably would not feel much below 6hz. I will have to give it a go but I am not the most confident when pushing subs to an extreme level. Ryan has no fear but I don't have a spare £350 for another driver going at the moment.

I think in the real word as long as you can get good spl readings at 10hz your a sure winner.

cheers

Graham
 

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Yah I think so.......I was just messing around with the 5-0 but I am glad there are people like Ryan to tell us if it can be done or not.

PLUS when it comes to movies aslong as I can reach those low hz on movies like Black Hawk Down and others I am happy. I dont need to reach 5hz at max spl. Which I am sure your subs will be suffice.

I think I will be perfectly happy with the lower range capabilities of four 18's. So 12hz tune 20ft boxes whatever it can hit down low I will be happy. Especially with 2400 watts to each 18.
HAHA :heehee: hahahaha:D hahahahah:devil: :hsd:
 

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Discussion Starter #189
Yep! your definitely going to have some fun there matey. One thing I would probably suggest is to get a couple of Reckhorn B2's and apply a hpf on them subs purely to keep the port velocity down but I would wait until you get them built and up and running first. My port velocity is quite high without a hpf at 38 m/s at 10hz at full power but I have not had any chuffing at all so you should be fine but with those two babies I doubt you will ever experience full power as you won't need to but atleast its there if you do. :devil:

You will be looking at 121.5db at 20hz with one sub and without room gain and 112db at 10hz! :hsd:

cheers

Graham
 

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So should I go with the slotted port or oval?

Do I need to have any certain size port?
 

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So should I go with the slotted port or oval?

Do I need to have any certain size port?
The exact diameter and length of the port is what creates the tune point of it. It has to be calculated and using an oval port, while undoubtedly will look fantastic, would make that calculation more difficult.
 

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I prefur the slotted port myself like Grahams.
 

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I was unable to look at the links. My computer could not open the files.

So we are talking about 18ft for the duals correct?

I hate asking this stuff when I should just be asking on my thread. Sorry to intrude or impose.
 

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Discussion Starter #195
That's not a problem matey. The velocity is max at 28 m/s on the 18 cu ft box where as its 32 m/s on the 20 cu ft box. Spl is only 1/2 db down on the 18 cu ft box.

cheers

graham
 

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Is that 1/2 spl down from 20hz and below?
 

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The exact diameter and length of the port is what creates the tune point of it. It has to be calculated and using an oval port, while undoubtedly will look fantastic, would make that calculation more difficult.
The calculation wouldn't be too much harder. The shape doesn't matter much to the tuning as long as you keep the relationship of the vent length, internal airspace of the enclosure and the area of the vent the same.
 

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If I didn't want so much bass I would make a oval port for a smaller box. BUT I like the look of the slotted port because it reminds me of the PA system subs.

AND that, to me, would make the subs look more industrial(extreme power, commercial application like) Just my opinion so I am going to stick with the slotted port.

Its always nice when you have an idea and there are people on here who can tell you exactly how to make it happen.

Graham did those lower hz tests yet.:bigsmile:
 
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