Small sealed enclosures (1 Viewer)

[Ryan T]

Hi,


I just got back home with my new shiva project. I was going to build a EBS shiva but when i got there i decided to go sealed. I built 2 boxes the first is a 25 L sealed box and the second is 54 L. I wanted to see what type of performance I could get from a very small box on the first design. The second box is my fall back box in case I didn't like the small sealed cube. well anyhow I've run the sub since yesterday for a few hours without any seal around the driver or terminal cup. I assumed with such a small box it would be difficult to push the cone back to see if there where any leaks. I was right, even thought there were air leaks around the driver it would only go back about 1/2" without putting to much pressure on the cone. After listening to it for a few hours I'm really impressed btw. It was a little boomy but not to bad. I could defiantly hear the air escaping out from around the driver so I went a got some weather stripping today. After installing the weather stripping it's now nearly impossible to push the cone in 1/2" it goes about 1/4" and thats about all. I'm a little worried with that much pressure will my speaker bust when it gets playing at higher excursion levels? I noticed it sounds a little tighter with the box air tight but it takes more power to get it to the same levels as before. I'm wanting to get a BFD and a more powerful amp to flatten the response of the box but it sounds pretty darn good as it is. I'm still in the testing phase. I haven't tried the 54 L sealed box yet but I hope to soon.



Thanks,
Ryan

 

[Chris Tsutsui]

Did you try putting some polyester filling on the inside yet? They sell 20oz bags at fabric stores and walmarts for like $2ea.

 

[Jeffrey Noel]

Ryan, sorry for the plug, but if you're looking for a BFD to buy contact me. Mine's been sitting in it's box since last August. :frowning:

 

[Ryan T]

Ryan, sorry for the plug, but if you're looking for a BFD to buy contact me. Mine's been sitting in it's box since last August.

No problem about the plug. I don't really have any money right now unfortunately. I need to get a nice amp before I get a BFD anyway.

I know i could probably do a search but does anyone have any tips on priming and painting my box? So for all of my DIY projects have been left bare MDF.



thanks,
Ryan

 

[Andrew Pratt]

I just finished building a 28Liter sealed shiva (see my other thread for details) and like you I've been pretty impressed with its performace. I haven't tried pushing in the driver but I might just do that tonight if I remember

 

[Dan Wesnor]

Don't worry, the surround will split before the box will explode. I know, I've seen it happen.

 

[Ryan T]

Don't worry, the surround will split before the box will explode. I know, I've seen it happen.

That's the part i'm worried about. I don't give a hoot about the box. It only cost $18 for the wood. The speaker on the other hand is way more expensive.

 

[Jeffrey Noel]

Ryan, I wouldn't worry about the pressure hurting the sub. Just think of all of the shiva's put in small enclosures for the car. I haven't heard of one screwing up unless someone's put WAY too much power to it. So just don't over power it and you should be fine.

 

[Ryan T]

Ryan, I wouldn't worry about the pressure hurting the sub. Just think of all of the shiva's put in small enclosures for the car. I haven't heard of one screwing up unless someone's put WAY too much power to it. So just don't over power it and you should be fine.

Yeah I guess thats true. I do need to get more power than i have now though. Currently I'm using an old stereo receiver to power it . I was thinking about getting the 120W PE plate amp. It has a 6db boost at 30 hz which i think will be beneficial since the sub starts dropping off so soon (F3 43 Hz). I just wish the boost was a little lower maybe at 25 Hz, oh well. I know that will make a big bump in the response but i'm going to cross the sub over at 50 Hz to blend with my mains. So from looking at the charts on lspCAD it shouldn't be to bad.



Ryan

 

[Jeffrey Noel]

I'd just go ahead and get the 250watt (272W actually) plate amp that has the bass boost at 30 hz. The extra headroom will be beneficial to you in the long room. Plus the amp isn't that much more than the 120W plate amp.

BTW, you can always mod the amp for the appropriate boost you want. It really doesn't look to hard to do, just switch out some resistor thingys.

 

[Dan Wesnor]

The driver that came open was a Stryke SB-10 in 45L. Split right open after about 30 minutes of LotR. I now use a Shiva in a 35L box, with a Linkwitz xform with no problems so far. Don't know exactly why the SB-10 failed, because it looks to be better built than the Shiva (rubber vs. foam surround). Maybe the Shiva leaks more air through the dustcap, which could help the situation.

I'd think a box failure would be quite spectacular, with bits of shrapnel flying everywhere.

 

[Ryan T]

I'd just go ahead and get the 250watt (272W actually) plate amp that has the bass boost at 30 hz. The extra headroom will be beneficial to you in the long room. Plus the amp isn't that much more than the 120W plate amp.

Actually the 250 watt amp is about $50 more for me. I get a dealer discount on all the stuff. I was going to get the 120 Watt w/boost for my small shiva and the 250 watt wo/boost for my tempest. lspCAD said i should be able to hit Xmax with my shiva using the 120 Watt amp. right now i have around 60 watts RMS and it plays plenty loud for me. I figure the 120 watt amp will give me more headroom. Another factor is the room my shiva is in is tiny at 11' by 14' by 8'.

 

[Andrew Pratt]

I figure the 120 watt amp will give me more headroom. Another factor is the room my shiva is in is tiny at 11' by 14' by 8'.

That's a logical answer to an illogical question You can never have too much power :tim allen grunt:

That said the 120 watt I have powering my small seal shiva does rather well for my with music...I haven't tried it in the theater yet though which is where I'd really tax it.

 

[Ryan T]

Well I just finished putting the terminal cup in my 54L box. I moved the shiva from the 24L box to the bigger one. All I can say is wow again! The bigger box sounds a lot closer to my .577 Tempest. It plays a little lower and seems a bit tighter sounding. Now I just have to decide on which box to put my shiva in :frowning:. The small one is more impressive and will be able to be finished nicely but the big one sounds better. Maybe I should just get another shiva lol. I might just go with the 250 Watt amp without the boost. I've been really pleased with the response of my tempest using the old receiver so I think i'll wait to get another amp for it. With the Shiva in either of the smaller boxes I need more power. Since I need a BFD anyways I decided I should just get the amp without the boost so I don't have to go in and disable it if I want to use the amp for my Tempest some time.





Ryan

 

[Stuart Mundy]

Hi Ryan

Any chance of a few pic's ?

Cheers
Stuart

 

[Ryan T]

Heres a page i just threw together real quick. It's not to dialup freindly though.


http://www.geocities.com/ryandtodd/DIYsubwoofers




Ryan