fivelitermustang Posted March 16, 2003 Share Posted March 16, 2003 I just ordered two Shiva subwoofer drivers. My plan is to put them into a sealed 5 cubic foot box or a 6 cubic foot ported box down to 25Hz. I have no motivation to make some veneered, nice looking box. I just plan on building a solid box out of 3/4" MDF. In the car I will power these with an amp that will give it a two-ohm load. I am curious about a few things. --What kind of amp would I need to run that will give me a two-ohm load or eight-ohm load that I could plug into a 120V house socket? What kind of power would I need as well. --Would the sound still be decent in the room in terms of SQ from using just a MDF carpeted box? I'm just looking to add some crazy bass impact in my 15'*15' room because my Klipsch ProMedia ain't cuttin' it for my rap/hip-hop music. Quote Link to comment Share on other sites More sharing options...
formica Posted March 17, 2003 Share Posted March 17, 2003 You forgot to mention a couple of basic specs for your shivas... such as voice coil setup (dual in your case), power-handling (650W combined), efficiency (87.2db 1W@1m), resistance (4ohm nom in each VC)... The Shivas are actually good SQ subs for room use, so you can use it successfully for both car and home. As you already know, they do require somewhat of a large box for car use though. Im quite sure that your carpeted box will not affect the SQ of your sub even for interior use... as long as its well built (sealed and VERY well braced). For your other question, Im assuming your asking which 120V amp would be able to pump out ±1200W into 2 ohms in your home? If youll be using it with your ProMedia, I dont think youll need to push your sub very hard (ie: 1200W) to overpower your main speakers. Actually this would represent an in-room SPL at 1m of about 130db for your vented enclosure or 137db for the sealed one! Even a 300W would give you phenomenal performance versus your klipsch. If you install a plug on the rear of your box for each voice-coil, you will be able to modify the wiring to accommodate your power amp (ie: 2,4,8,16ohms) and whether it can be bridged or not. If youd like an amp that can be bridged and put out decent power into 2ohms you will have to buy a pro-amp such as the QSC RMX series which are very popular with the DIY crowd right now. http://www.qsc.com/products/amps/rmx/rmx.htm and the RMX 850 sells for under 300$ hope it helps some... Rob B. Quote Link to comment Share on other sites More sharing options...
Dustin B Posted March 17, 2003 Share Posted March 17, 2003 If this is for car use you may want to consider returning the Shivas and getting a single 12" Brahma from Adire instead. Will cost you a little more than a pair of Shivas, but will work in a much smaller box and be able to compete with the output of a pair of Shivas and easily best them in sound quality. Couple other comments. You can't bridge a QSC amp into a 2ohm load (well you could probably run them bridged at 2 ohms, but don't expect to be able to push them). They can run 2 ohm loads in stereo, but when bridged can only handle 4 ohm loads. Also don't get too hung up on power handling. Remember a driver has thermal limits and excursion limits that are both related to power input. The vast majority of the time the driver will reach it's excursion limits long before it reaches it's thermal limits. Especially drivers like the Shiva and Tempest. The XBL^2 drivers from Adire are a different story though. There are suitable allignments for these drivers that can ask for power that approaches the drivers thermal limits. Good thing it's so high on those drivers. Quote Link to comment Share on other sites More sharing options...
fivelitermustang Posted March 17, 2003 Author Share Posted March 17, 2003 My original idea is kind of ridiculous... so instead I will just order the following. Adire Tempest Adire AVA250 Amplifier (for home) JBL BP600.1 (for car) The last question is... could the AVA250 be hooked up to the computer soundcard output? I have all my MP3s on my PC and this is where I want to use the sub. Quote Link to comment Share on other sites More sharing options...
Dustin B Posted March 17, 2003 Share Posted March 17, 2003 Depends on the soundcard. But even if it has a sub output (would be on the 5.1 break out cables) I highly doubt it will have any bass management. Without bass management only sources with a dedicated LFE signal will feed it bass. There are hacked drivers for M-Audio cards that will provide pretty good bass management though. Quote Link to comment Share on other sites More sharing options...
fivelitermustang Posted March 17, 2003 Author Share Posted March 17, 2003 Couldn't you just use a y-splitter to split one of the channels into two and then run one of the channels to a soundcard with a lowpass filter? Quote Link to comment Share on other sites More sharing options...
Dustin B Posted March 17, 2003 Share Posted March 17, 2003 The AVA250 has inputs for both the left and right channel. So you could put a Y on both the left and right channel outputs of your sound card. But this will only get you a low pass filter, your mains will still be getting a full range signal. It won't give a great response curve but it will definately get you bass. Quote Link to comment Share on other sites More sharing options...
fivelitermustang Posted March 17, 2003 Author Share Posted March 17, 2003 Yeah... I will probably end up doing that... for now. I understand that the response curve will be kind of crappy. The Tempest will be able to do the extreme lows while the ProMedia satellites will do the mids to highs. There will probably be a gap in the sound originally where Tempest ends to where the v2.400 subwoofer crosses over to the satellites. Is there anything that can be done to remedy this? I plan on getting some towers a little later in a couple of months. But I will try to make due with what I have at the moment. Quote Link to comment Share on other sites More sharing options...
Dustin B Posted March 17, 2003 Share Posted March 17, 2003 Not really, but unless you have a seperate amp you won't be able to not use the Promedia's subwoofer. Quote Link to comment Share on other sites More sharing options...
formica Posted March 18, 2003 Share Posted March 18, 2003 Fiveliter: Cant you plug the plate amp into the soundcard line-level output... and then plug the Promedia into the plate amps pass through line-level outputs... without using any Ys? Youd have to make a couple of cables and your Promedias will be fed full frequency but it should work without the gap in the frequency range. (no high pass out on the AVA250, right?) Dustin: Actually, isnt the Tempest/AVA250 more or less what you got Dustin? I was considering a Tempest sub as well since Im also in Canada so Adire is quite attractive because of CSS. I remember seeing your comments (I think at HT forum) about what youd do differently but I cant seem to find it now... Having lived with your setup, what would you do differently? Ive already ordered a pro JBL power amp on liquidation (a realistic 225Wx2@8ohms or an optimistic 700Wx1@2ohms). Seeing that the Tempest runs 225$cnd shipped versus ±330$cnd shipped for the Stryke AV15, do you think the Stryke is worth the cost difference? Thanks... Rob PS: excuse me if i'm sometimes overlapping my HTF posts, but i'm learning tons of stuff... Quote Link to comment Share on other sites More sharing options...
Dustin B Posted March 18, 2003 Share Posted March 18, 2003 Tempest AVA250 is exactly what I have. It's way more sub than the Promedia's could keep up with. The jist of it was I would put a base plate on it for appearence reasons (would also make moving it easier). I wouldn't bother with the threaded rod. And I might attempt to flush mount the amp. There are some other more minor construction specific things listed on my webpage. Quote Link to comment Share on other sites More sharing options...
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