Whattup fellas I got a couple of problems I need help with.
1 My bro is installing a system in a 98 Civic for one of his buddies. He is planning to run a pair of MB Quart RWE 302 12 inchers in a "1 cubic foot sealed box tuned at 14-20hz." This makes absolutely no sense to me as you usually tune a ported box correct? Even if this "tuned sealed" enclosure is possible, wouldnt a tuning such as that cause speaker damage due to overexcursion? The bottom of the frequency response is 18hz. If you guys can confirm my suspision on this not working, and possibly come up with a logical solution, that would be great. I have no specs for this besides it's a 2 Ohm DVC model.
2 The amp with this setup is a MB quart RAA1000. Its rated 500RMS at 4 and 2 Ohms and 1000 RMS at 1 Ohm. these are the only specs I have. Problem here is the brother wants to make it run 1 Ohm with a pair of 2 Ohm DVC subs. I don't beleive this to be possible, but would love to be proven wrong. I can't think of a way to make run anything but either a half or 2 Ohms, but I'm only knowledgeable, not an expert.
3 Suppose we do get it to push 1 Ohm, is this safe on a 98 Civic's electrical system? I'm going to tell him to do big three upgrades, but won't the alternator and battery need upgraded to run current like that? 1000 watts RMS is a grip of juice for any stock electrical system to run in my knowledge, but agian, I have no problem being proven wrong.
4 Just for extra information, he is planning to run a killer Monster 1/0AWG kit. He has not even metioned a capacitor, and I can't picture a 1000RMS amplifier or a Honda's charging system being the least bit pleased with that. My bro isn't very stereo savvy, and he wants my help with the install. I don't think this is very well planned out at all, and would like some input to save our @$$es, because it sounds like this gonna hit the fan feel me? We do plan on building our own boxes of MDF on this project.
Replies (7)
swez on 10/5/2006 09:47:27
General specs on that amp and subs:
http://www.woofersetc.com/index.cfm?fuseaction=product.display&product_id=359
http://www.woofersetc.com/index.cfm?fuseaction=Product.display&product_id=3415
1. Technically, we cannot tune a sealed woofer system. However, we can improve or alter the low bass response curve by adjusting the size of the enclosure. The larger the Qtc we use (Ie: 0.707 "Q") the lower the sub can go with some sacrifice to power handling. In small "Q" enclosures, ("Q" of >0.85) we tend to roll off low bass sooner, but power handling is better. You are correct about excursion factors. Power handling, excursion levels and general bass response curves are all related to the sub design, "Q" factor of the box and how much power is used for a given system.
2. If he wants to run this amp and sub combo, the best he can get safely for this amp is 2 ohms. Not a bad place to be, but no way can he get 1 ohm loading from a pair of these subs. (2+2 DVC's) The amp specs 250 @ 4 ohms, 500 @ 2 ohms and 1000 watts @ 1 ohm.
He'd need to use a pair of 4+4 DVC's like the DWF-304 to achieve full capability of a 1 ohm loading off that amp.
http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=2902
3. At 1 ohm loads and pushed close to full power, this amp will draw some serious current. (80 A's @ full power) He'll probably get some light dimming at night with low engine RPM speeds and long, deep bass hits. However, if he uses this power with some degree of restraint, the "BIG 3" and perhaps a larger CCA rated BAT will minimize that issue.
4. A 1/0 power line is not a bad option here. This allows him to add a strong 4 channel amp later. However, A full range class A/B amp pulls good A's too. To keep up with that sub rig, he'll probably need 75-100 watts per channel for his mid/highs. With that addition, it is likely he'll need to upgrade his ALT at this point.
Swez
ShootuhMcBustaCap on 10/5/2006 15:07:52
Thanks Swez you da man! I figured all of that, but as I said, I don't know it all. Would a ported box be useable for this sub? He ebayed the subs and has already purchased them, so going 4 Ohm is not an option. He should of planned for that, not my problem. He has a life, so he has better things to do than think about stereos. Me on the other hand, not the case. Thanks agian, They aren't many people I can ask questions like this.
swez on 10/5/2006 17:38:07
Not sure if these subs are designed for Porting. We can port almost any given sub, but a sub with an EBP (Efficiency Bandwidth Product = Fe/Qes) that is higher than 50, is a good candidate for porting. Those under 50, are not recommended for ported applications.
Read this and other associated topics in this site and you will learn a lot about many aspects of car audio and more:
http://www.bcae1.com/spboxad2.htm
Swez
PS If your bro goes for the full boat 1000 watts @ 1 ohms, he'd be well served using sealed of about 1 cf per sub. A sealed box is air pressure loaded for limiting X-max (Excursion limits) at high input power ranges. The low bass will still be there, but it rolls off gently below about 45 Hz. That is good for this amp and sub combo. Yes, he will get very good low bass as well, once the subs break in properly in a week or so.
ShootuhMcBustaCap on 10/5/2006 20:00:56
Right on man, your a god amongst us mere stereo installing mortals.
swez on 10/6/2006 06:14:51
TY for the kuddos... but frankly I don't ever wish to be God... He's got his hands full now and I don't want that job either. However, with talant on loan from God, will use that to serve others here and elsewhere as needed. That's good enough!
Swez ><>
ShootuhMcBustaCap on 10/8/2006 22:51:50
Word, I can feel that. It's nice to have an "Answer Guy" such as you, because people usually come to me for advice, it's hard for me to find anybody to learn from.
swez on 10/9/2006 10:19:11
Got that and often see the same deal... think asking more questions of wiser men is always a open door to higher learning and we all need a piece of that pie, now and then.
It's good to have answer guys around and poll them regularly too. There are several of them here too... just read some of the old postings, FAQ's and DIY'er articles and see.
swez
PS I too, am always searching for new mentors and teachers. Finding wisdom and knowledge is never easy nor does it come cheap. We have to dig deep to find the best nuggets that others miss because they gave a up a few feet too soon. Ehhemmm, where's my pick axe and shovel?
1 My bro is installing a system in a 98 Civic for one of his buddies. He is planning to run a pair of MB Quart RWE 302 12 inchers in a "1 cubic foot sealed box tuned at 14-20hz." This makes absolutely no sense to me as you usually tune a ported box correct? Even if this "tuned sealed" enclosure is possible, wouldnt a tuning such as that cause speaker damage due to overexcursion? The bottom of the frequency response is 18hz. If you guys can confirm my suspision on this not working, and possibly come up with a logical solution, that would be great. I have no specs for this besides it's a 2 Ohm DVC model.
2 The amp with this setup is a MB quart RAA1000. Its rated 500RMS at 4 and 2 Ohms and 1000 RMS at 1 Ohm. these are the only specs I have. Problem here is the brother wants to make it run 1 Ohm with a pair of 2 Ohm DVC subs. I don't beleive this to be possible, but would love to be proven wrong. I can't think of a way to make run anything but either a half or 2 Ohms, but I'm only knowledgeable, not an expert.
3 Suppose we do get it to push 1 Ohm, is this safe on a 98 Civic's electrical system? I'm going to tell him to do big three upgrades, but won't the alternator and battery need upgraded to run current like that? 1000 watts RMS is a grip of juice for any stock electrical system to run in my knowledge, but agian, I have no problem being proven wrong.
4 Just for extra information, he is planning to run a killer Monster 1/0AWG kit. He has not even metioned a capacitor, and I can't picture a 1000RMS amplifier or a Honda's charging system being the least bit pleased with that. My bro isn't very stereo savvy, and he wants my help with the install. I don't think this is very well planned out at all, and would like some input to save our @$$es, because it sounds like this gonna hit the fan feel me? We do plan on building our own boxes of MDF on this project.
Replies (7)
swez on 10/5/2006 09:47:27
General specs on that amp and subs:
http://www.woofersetc.com/index.cfm?fuseaction=product.display&product_id=359
http://www.woofersetc.com/index.cfm?fuseaction=Product.display&product_id=3415
1. Technically, we cannot tune a sealed woofer system. However, we can improve or alter the low bass response curve by adjusting the size of the enclosure. The larger the Qtc we use (Ie: 0.707 "Q") the lower the sub can go with some sacrifice to power handling. In small "Q" enclosures, ("Q" of >0.85) we tend to roll off low bass sooner, but power handling is better. You are correct about excursion factors. Power handling, excursion levels and general bass response curves are all related to the sub design, "Q" factor of the box and how much power is used for a given system.
2. If he wants to run this amp and sub combo, the best he can get safely for this amp is 2 ohms. Not a bad place to be, but no way can he get 1 ohm loading from a pair of these subs. (2+2 DVC's) The amp specs 250 @ 4 ohms, 500 @ 2 ohms and 1000 watts @ 1 ohm.
He'd need to use a pair of 4+4 DVC's like the DWF-304 to achieve full capability of a 1 ohm loading off that amp.
http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=2902
3. At 1 ohm loads and pushed close to full power, this amp will draw some serious current. (80 A's @ full power) He'll probably get some light dimming at night with low engine RPM speeds and long, deep bass hits. However, if he uses this power with some degree of restraint, the "BIG 3" and perhaps a larger CCA rated BAT will minimize that issue.
4. A 1/0 power line is not a bad option here. This allows him to add a strong 4 channel amp later. However, A full range class A/B amp pulls good A's too. To keep up with that sub rig, he'll probably need 75-100 watts per channel for his mid/highs. With that addition, it is likely he'll need to upgrade his ALT at this point.
Swez
ShootuhMcBustaCap on 10/5/2006 15:07:52
Thanks Swez you da man! I figured all of that, but as I said, I don't know it all. Would a ported box be useable for this sub? He ebayed the subs and has already purchased them, so going 4 Ohm is not an option. He should of planned for that, not my problem. He has a life, so he has better things to do than think about stereos. Me on the other hand, not the case. Thanks agian, They aren't many people I can ask questions like this.
swez on 10/5/2006 17:38:07
Not sure if these subs are designed for Porting. We can port almost any given sub, but a sub with an EBP (Efficiency Bandwidth Product = Fe/Qes) that is higher than 50, is a good candidate for porting. Those under 50, are not recommended for ported applications.
Read this and other associated topics in this site and you will learn a lot about many aspects of car audio and more:
http://www.bcae1.com/spboxad2.htm
Swez
PS If your bro goes for the full boat 1000 watts @ 1 ohms, he'd be well served using sealed of about 1 cf per sub. A sealed box is air pressure loaded for limiting X-max (Excursion limits) at high input power ranges. The low bass will still be there, but it rolls off gently below about 45 Hz. That is good for this amp and sub combo. Yes, he will get very good low bass as well, once the subs break in properly in a week or so.
ShootuhMcBustaCap on 10/5/2006 20:00:56
Right on man, your a god amongst us mere stereo installing mortals.
swez on 10/6/2006 06:14:51
TY for the kuddos... but frankly I don't ever wish to be God... He's got his hands full now and I don't want that job either. However, with talant on loan from God, will use that to serve others here and elsewhere as needed. That's good enough!
Swez ><>
ShootuhMcBustaCap on 10/8/2006 22:51:50
Word, I can feel that. It's nice to have an "Answer Guy" such as you, because people usually come to me for advice, it's hard for me to find anybody to learn from.
swez on 10/9/2006 10:19:11
Got that and often see the same deal... think asking more questions of wiser men is always a open door to higher learning and we all need a piece of that pie, now and then.
It's good to have answer guys around and poll them regularly too. There are several of them here too... just read some of the old postings, FAQ's and DIY'er articles and see.
swez
PS I too, am always searching for new mentors and teachers. Finding wisdom and knowledge is never easy nor does it come cheap. We have to dig deep to find the best nuggets that others miss because they gave a up a few feet too soon. Ehhemmm, where's my pick axe and shovel?
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