[doors]

Hi,

I am planning to make a sub. It will be my first attempt at DIY, rather semi DIY as I personally probably wont be doing much, just buy the driver and the plate amp and get the cabinet made by a carpenter.

My budget is around 700-800$ including shipping.

The sub should be musical, but should also have good SPL for movies. Dual subs are ruled out, though I can have 2 drivers (e.g. shiva 12?) in the same sub, passive radiator might not be ok (gotta check with wife). I would prefer to go for a sealed sub as its a lot easier to build, also supposedly is better for music. I just want to be sure that it will be good for movies too.

I am considering maelstrom x 18" driver for this as it has impressive reviews. Is it a good candidate for my needs. What should I look for in an amp for this sub in terms of specs. Is 500w bash amp going to be enough in a 6200 cubic ft area. Will it give good enough SPL in a sealed design and still be musical enough. Do I need lpf and/or hpf in the amp.
Pro amps are ruled out, I have to go for a plate amp as wife does not want another component in the rack, till I change the rack itself, which is quite far away. PR is also probably ruled out because I have two small kids and the less exposed parts there are the better.
Can the maelstrom be mounted in a down firing position. I have heard that some subs tend to sag at surround over time due to the weight and maelstrom is quite a heavy one.

Any sample sealed and ported designs that are readily available that I can see.

Is there a waiting time for the mal-x, or does it get shipped immediately. How much approximate time for delivery to the bay area.

Listening area
The main listening area is 19.5 x 18.5 x 10.5
3787 cubic feet. The system is kept along the 18.5 ft wall. The listening positions is about 12 ft.
But the Dining and open kitchen is attached to it, and the total area is 31.5 ft x 18.5 x 10.5 = 6118 cubic feet
Let me know if a rough diagram of the room will help in suggesting a sub and I will post it.

Usage
50% music and 50% movies
I mainly listen to classic rock, blues, heavy metal, jazz, classical music etc. Watch all sorts of movies from classics to action, scifi etc.

Current setup
Yamaha RX-V663 AVR, marantz cd6000 OSE cd player, B&W 602 S2 for mains, LCR 600S3 center channel, B&W rock solid for surrounds, HTPC with M-Audio revolution 7.1 sound card.


Maximum permitted size (WAF:)) for the sub - W ? 24?, D ? 24?, H = 24?, but its preferrable if the dimensions dont exceed 22"

Is a 500w bash amp enough for my needs. What do I gain by going to a higher wattage amps, I don?t usually play at very high volumes, except rarely.

Model : LT/1300
450$
Number of Channels : 1
Power Rating : 1300W RMS @ 4O
Height : 12.000" - Width : 12.000" - Depth : 5.500"
I heard this one had current inrush problems, and needs a 20A socket, would rather not get this.

Model : LT.500
300$
Number of Channels : 1
Power Rating : 500W RMS @ 4O
Height : 10.625" - Width : 9.875" - Depth : 5.5"

CSS bash 500
230$

CSS hpsa1000
450$

OAUDIO 500W bash amplifier
220v ? 249$

Does the driver comes with the nuts bolts etc for mounting.
why most of the people try to avoid nails and use only glue. What about nails along with glue. What about nuts instead of nails.

[JohnR]

Any sample sealed and ported designs that are readily available that I can see.

Hi, have a look at the application note on the Maelstrom page -

http://www.diycable.com/main/product_info.php?cPath=24_93_150&products_id=681

If you can swing the 24" cube, that should give you a bit over 6 cu ft when all is said and done.

[Kevin Haskins]

The Maelstrom really is best with large amplifiers.   Basically, when you design all that stroke into a driver it requires extra power to use it.    Efficiency in subwoofers is highly influenced by the box size we design around, and the bandwidth of choice.   The actual efficiency that pops out the other end of that equation fixes our driver efficiency so there isn't anything we can do in the driver design to better utilize power.

Consequently, if you went with a Maelstrom I'd target >1000W amplifiers.   I have several customers using up to 4000-5000W of power in small heavily equalized sealed boxes.    You can get by with significantly less in a non-equalized application.

For your budget, the Shiva-X is going to be about your only choice.    You have to budget for everything which includes the driver, ports/passive radiators, amplification, cabinet, and signal processing (often built into the amp).    Once you go through that process even my cheapest solution is in the $500 area (Shiva-X, 500W plate amp, cabinet etc.. etc...).     That is if your not counting labor or other misc. cost like tools.     

Give me a call if you like.   Sometimes it is easier to cover all the design tradeoffs in a phone call.

[NavyDoc]

I built a 24" sealed cube with this driver.  Currently powered with an Adcom GFA555 (bridged) in a large open basement (18" x 29" x 8").  When playing U571 at near THX reference the clipping indicators started to flash so I backed off the volume.  However, the volume was beyond what I would normally listen.  I listen to music at -10 to -15 dB THX reference, and the bridged amplifier is not hot after 1-2 hours of listening pleasure.

Since I have added the sub I find I listen to a lot more music than before I added the sub.  My musical taste seems to be in line with what you have listed.  Planning on renting some Blu-Ray concert discs to really test the system.

Bottom line:  Awesome sub driver, but I will be adding a larger amp (not absolutely necessary for reasonably loud volume [-10 dB from THX reference]).

[doors]

The Maelstrom really is best with large amplifiers.   Basically, when you design all that stroke into a driver it requires extra power to use it.    Efficiency in subwoofers is highly influenced by the box size we design around, and the bandwidth of choice.   The actual efficiency that pops out the other end of that equation fixes our driver efficiency so there isn't anything we can do in the driver design to better utilize power.

Consequently, if you went with a Maelstrom I'd target >1000W amplifiers.   I have several customers using up to 4000-5000W of power in small heavily equalized sealed boxes.    You can get by with significantly less in a non-equalized application.

For your budget, the Shiva-X is going to be about your only choice.    You have to budget for everything which includes the driver, ports/passive radiators, amplification, cabinet, and signal processing (often built into the amp).    Once you go through that process even my cheapest solution is in the $500 area (Shiva-X, 500W plate amp, cabinet etc.. etc...).     That is if your not counting labor or other misc. cost like tools.     

Give me a call if you like.   Sometimes it is easier to cover all the design tradeoffs in a phone call.

I am worried about shiva not being enough in such a large room with it being a 12" driver.  Is shiva suitable for a down firing sub, I heard people complaining about surround sag in some other drivers. Do you have a design for ported shiva with 500w amp in around 6-7 cuft box (a winisd project file would be really helpful as I am a newbie and just learning things). What kind of SPL can I expect. I want it tuned at about 20hz, lesser is even better.

Any news on the tempest front? Is that a good one for ported designs?

[Kevin Haskins]

The Maelstrom really is best with large amplifiers.   Basically, when you design all that stroke into a driver it requires extra power to use it.    Efficiency in subwoofers is highly influenced by the box size we design around, and the bandwidth of choice.   The actual efficiency that pops out the other end of that equation fixes our driver efficiency so there isn't anything we can do in the driver design to better utilize power.

Consequently, if you went with a Maelstrom I'd target >1000W amplifiers.   I have several customers using up to 4000-5000W of power in small heavily equalized sealed boxes.    You can get by with significantly less in a non-equalized application.

For your budget, the Shiva-X is going to be about your only choice.    You have to budget for everything which includes the driver, ports/passive radiators, amplification, cabinet, and signal processing (often built into the amp).    Once you go through that process even my cheapest solution is in the $500 area (Shiva-X, 500W plate amp, cabinet etc.. etc...).     That is if your not counting labor or other misc. cost like tools.     

Give me a call if you like.   Sometimes it is easier to cover all the design tradeoffs in a phone call.

I am worried about shiva not being enough in such a large room with it being a 12" driver.  Is shiva suitable for a down firing sub, I heard people complaining about surround sag in some other drivers. Do you have a design for ported shiva with 500w amp in around 6-7 cuft box (a winisd project file would be really helpful as I am a newbie and just learning things). What kind of SPL can I expect. I want it tuned at about 20hz, lesser is even better.

Any news on the tempest front? Is that a good one for ported designs?

There is no problem using it down-firing.   I know people that have the original Shiva down-firing going on 10 years without any sag.

Your box limitations and budget are the two things that are limiting your choices.    If you are willing to push on either of those, you can get more output.   The Tempest will be available soon but it is going to require a larger box for ported builds.   

To hit both your budget, and size constraints the Shiva-X is the best choice (you should come out under-budget even with the box).    Follow the application notes and you will get good results.    Don't worry about the tune because it depends upon the build.   Once again, follow the application notes.

The version in the application notes was in a "subwoofer shoot-out". 

http://www.avsforum.com/avs-vb/showthread.php?t=1127851&highlight=great+southern&page=18

Note that most of the subwoofers in this comparison are much more expensive than the Shiva-X build I recommend which can be done for <$450 even including the MDF to build the cabinet.   If you use expensive veneer you can push the price higher.   A slot ported version could be done for <$400

[doors]

any recommended 500w bash plate amps. you specifically mention not to use a particular one in the app notes as it doesnt match, thats the one I was planning to get earlier. thanx for the warning  It should have an inbuilt subsonic filter as dont want to get an external one.

[Kevin Haskins]

any recommended 500w bash plate amps. you specifically mention not to use a particular one in the app notes as it doesnt match, thats the one I was planning to get earlier. thanx for the warning  It should have an inbuilt subsonic filter as dont want to get an external one.

The PE BASH 500W works but you need to change two resistors on the board to get the right subsonic filter.    PE has another 500W amp that doesn't require any soldering.    If you want one, I can get them with free shipping to your address.    Just let me know.

[doors]

I remember reading somewhere that their warranty is void if the filter is changed. what about the css one, does that work fine?

[Kevin Haskins]

I remember reading somewhere that their warranty is void if the filter is changed. what about the css one, does that work fine?

No.... Bob gets those from PE so it is the same amp.

Get Part # 300-806

They have it for $250 on sale.    You don't need to modify anything with that amp.

[doors]

uh oh... just checked, all the pe amps are 110volts. I need a 220v amp as a friend of mine will be bringing it to india.

the bash amp mentioned in the manual, is it bad for that particular design, or bad with shiva, or with all ported designs irrespective of the driver.

[Kevin Haskins]

uh oh... just checked, all the pe amps are 110volts. I need a 220v amp as a friend of mine will be bringing it to india.

the bash amp mentioned in the manual, is it bad for that particular design, or bad with shiva, or with all ported designs irrespective of the driver.

You just need an amplifier that has the appropriate subsonic filter.   There are two issues.   Most of these subsonic filters have a corner, that needs to be set just below the tuning frequency.    They also have a Q, which is sometimes used to add boost.    The subsonic filter cannot have more than 1-2dB of boost at the corner frequency.     Other than that you just need an amplifier that has the appropriate power into a nominal 4-ohm load and you need whatever other filter functions needed for your application.    If your not hooking it up to a HT processor you may need a variable low-pass filter to integrate it into the mains and a variable volume control.   

[doors]

the boost on bash 500 can be changed with just changing 2 resistors and it can be set to any frequency.

[Kevin Haskins]

the boost on bash 500 can be changed with just changing 2 resistors and it can be set to any frequency.

It can be set to a range of frequencies, within what is reasonable for that network.    They have documentation showing the different corner frequencies and boost in their application notes.   

I will say, that it is a pain in the butt to get to the resistors.    They are not out on the board in a place that facilitates easy removal and replacement.