Which sub do you have in HT system?

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BeerCan

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Originally Posted By: grampi
Originally Posted By: Quattro Pete
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Specifications: •Rated power output: 497 watts into 8 ohms, 950 watts into 4 ohms with 0.92% THD (based on one-third power duty cycle)
What the heck is that? How does that compare to RMS?
Got me, I was hoping someone else would know...I've never seen that term used before...
It means that the amp should be used at 1/3 the rated watts for best results. So it can supply 1/3 the power continuously and the rest is just for short bursts when needed.
 
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Originally Posted By: dave123
Originally Posted By: grampi
Originally Posted By: BeerCan
I like the rythmic driver. Years ago I purchased one and built my own enclosure. They sell them complete now http://www.rythmikaudio.com/products1.html I prefer sealed subs but for HT ported might give you better slam.
They've got a couple of 15" models that look pretty bad a$$! They're a little pricier though...
I would also look hard at the Rythmik. Beer Can knows what he's talking about if went with SVS I'd look at a PB2000 but would want a ultra 13 at the end 1000 bucks on a good sub is just scratching the surface.
I'll also recommend Rythmik. I have a LV12R in my home theater. It's big but I'm happy with it. I may add a second one down the road. After doing a bunch of reading it was between the Rythmik and an SVS sub for me and my price range. I do have SVS L/C/R and rear surrounds and am very happy with them too.
 

grampi

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Originally Posted By: mjoekingz28
You should know better than that!
???
 
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I have a single Sunfire HRS-12 in my fairly large family room. It's pretty darn good and produces some very tight bass that goes well into the sub-audible range. As a wannabe audiophile, I do appreciate a great sounding system with tight, strong bass. In particular, I listen to hard rock and want drums tight, not sloppy. Something many subs have trouble with. As many big subs tend to convert a sharp drum into a thud. The HRS-12 is a compact, 1000 watt, sealed, very long throw sub with extremely tight bass and punch that fits my preference. I tend to dislike most ported subs, as I feel they sound sloppy. I make no claims that it's the worlds best sub. Only that I liked it's accurate sound the best. They can be found in your price range.
 
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Originally Posted By: grampi
When I was still in the AF, I made my own sealed enclosure using a cheap MTX car audio 15" driver, and a cheap PE 250 watt plate amp. Considering I was using cheap components, and though it was no reference unit by any stretch, it performed surprisingly well. It was made of MDF, which I spray painted flat black...it was an eyesore. So I decided I wanted to make an enclosure that looked like furniture, and I upgraded the driver to a Tempest, while using the same amp in a larger sealed enclosure. We moved before I got to play this sub, and the house we bought here has double the living room area. The output isn't as good as the previous one, and it's real boomy. And then one day the amp just quit working, so I was never able to play with it enough to get it sounding like I want it to, but I do think the Tempest needs more than 250 watts...oh, and it's corner loaded in the living room...and the amp is playing into both 8 ohm VCs paralleled for a 4 ohm load...
This explains a lot. First, the word "cheap". Second, "car audio". A 15" driver such as this has a very stiff suspension (spider + surround). It has to for self-protection as it's not designed to fit into a box, much less one that will fit into any car. Instead, the car is it's "box". It's called an "infinite baffle". The outer surface of the sheet metal becomes a secondary radiator. That's why bass can be heard the next block over.... Third, boomy bass is a sure sign of mis-alignment. Many times the box is too small. Anytime you put a driver into any enclosure, its resonant freq. rises. Once several mis-alignments line-up, you get one-note-bass. Sort of like putting a bus engine into a VW. Put such a beast into a corner where you have the intersection of three orthogonal planes, easily exciting all the room modes, will make the sound worse. Not sure why the amp quit..... Note regarding "8 Ohms" and such: A voice coil has some wiring resistance (DC), but it's also an inductor, which is fed an AC signal by the amplifier. There should be no DC voltage at all. If there is, somethings wrong. The drivers impedance varies constantly due to frequency. Further, depending on freq., at times it will present a capacitive, inductive or (rarely) resistive load to the amp. Most amp output stages dont like a capacitive load at all. Drives them nuts. The point is there is a lot of freq-dependant interactions going on between amp, any crossover, and the driver. Also, consider that the VC is a generator itself and as such generates a back-EMF that now the amp's output stage must deal with! Though this may be well over your head, my point in elaborating is to be educational.
 
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Originally Posted By: grampi
..I also noticed my 4 cft sealed enclosure can be ported...adds 3db which is like doubling the power...
No....where are you getting this? You're confusing acoustical power with electrical power. Not the same thing. Second, a bass reflex alignment is a 4th order system. If you haven't had success building a sealed system, your odds of success are very small indeed. Your money is best spent BUYING an established, proven design!
 

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Originally Posted By: sleddriver
Originally Posted By: grampi
When I was still in the AF, I made my own sealed enclosure using a cheap MTX car audio 15" driver, and a cheap PE 250 watt plate amp. Considering I was using cheap components, and though it was no reference unit by any stretch, it performed surprisingly well. It was made of MDF, which I spray painted flat black...it was an eyesore. So I decided I wanted to make an enclosure that looked like furniture, and I upgraded the driver to a Tempest, while using the same amp in a larger sealed enclosure. We moved before I got to play this sub, and the house we bought here has double the living room area. The output isn't as good as the previous one, and it's real boomy. And then one day the amp just quit working, so I was never able to play with it enough to get it sounding like I want it to, but I do think the Tempest needs more than 250 watts...oh, and it's corner loaded in the living room...and the amp is playing into both 8 ohm VCs paralleled for a 4 ohm load...
This explains a lot. First, the word "cheap". Second, "car audio". A 15" driver such as this has a very stiff suspension (spider + surround). It has to for self-protection as it's not designed to fit into a box, much less one that will fit into any car. Instead, the car is it's "box". It's called an "infinite baffle". The outer surface of the sheet metal becomes a secondary radiator. That's why bass can be heard the next block over.... Third, boomy bass is a sure sign of mis-alignment. Many times the box is too small. Anytime you put a driver into any enclosure, its resonant freq. rises. Once several mis-alignments line-up, you get one-note-bass. Sort of like putting a bus engine into a VW. Put such a beast into a corner where you have the intersection of three orthogonal planes, easily exciting all the room modes, will make the sound worse. Not sure why the amp quit..... Note regarding "8 Ohms" and such: A voice coil has some wiring resistance (DC), but it's also an inductor, which is fed an AC signal by the amplifier. There should be no DC voltage at all. If there is, somethings wrong. The drivers impedance varies constantly due to frequency. Further, depending on freq., at times it will present a capacitive, inductive or (rarely) resistive load to the amp. Most amp output stages dont like a capacitive load at all. Drives them nuts. The point is there is a lot of freq-dependant interactions going on between amp, any crossover, and the driver. Also, consider that the VC is a generator itself and as such generates a back-EMF that now the amp's output stage must deal with! Though this may be well over your head, my point in elaborating is to be educational.
That was very educational, but if I had to take a test on the material, I would fail miserably... Every sub I used in a vehicle was in an enclosure, except a pair of subs that were meant for infinite baffle applications...most of the enclosures I built were sealed, a few were isobaric/ported. All of them sounded good. The first driver I used, the MTX, was cheap, as was the PE amp. The Tempest is NOT a cheap driver. While it may be made for automotive applications, I have heard them used as HT subs, and when in the proper enclosure, and set up properly, the ones I've heard would hold their own against any of the factory built units. The Tempest is a beast of a sub, and it isn't causing my problem. Like you said, I have other issues, I just have to figure out how to work them out...
 
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Originally Posted By: grampi
It's too bad I couldn't bring all of these units into my living room and listen to them all....that's the only true way of finding the one that works best for me....I can't even go listen to them in a show room, I have to rely on reviews and recommendations to choose one...hopefully I won't be disappointed with the one I end up choosing...I do appreciated all of the input though!
While the others don't offer it, SVS does have a free 45 day in home trial. Free shipping both ways, so that is an option. If you have a Magnolia (Best Buy) near you, they carry some of the SVS subs. As you know though, you need to hear them in your room to know if they will work or not. If you haven't, go check out AVS Forum. There is a DIY section there with lots of helpful guys. They can model the enclosure for your Tempest and tell you what the optimal enclosure size and port tune would be and recommend a good amp for it as well. I'm sure you could achieve much better results that way. If you are going to purchase a new sub/s, do yourself a favor and contact Tom V. @ Power Sound Audio. Tom was the V in SVS when they started out and has since started PSA. They make very solid products, but more than anything, Tom will give you an honest opinion without trying to upsell you. You won't regret it. I've dealt with him for over 15 years and he has gone above and beyond in the customer service department. As far as what sub/s do I have, 2 ported JTR Captivator 2400s. smile
 
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Originally Posted By: grampi
Originally Posted By: mjoekingz28
You should know better than that!
???
Most subs, I would have normally thought all were like this but I just saw an old Jensen on eBay that said 4 or 8 ohm or two or four ohm, but generally (if not always) you need to hook up BOTH voice coils. I am more schooled in car audio than home audio, but I would guess they are quite similar.
 

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Originally Posted By: mjoekingz28
Originally Posted By: grampi
Originally Posted By: mjoekingz28
You should know better than that!
???
Most subs, I would have normally thought all were like this but I just saw an old Jensen on eBay that said 4 or 8 ohm or two or four ohm, but generally (if not always) you need to hook up BOTH voice coils. I am more schooled in car audio than home audio, but I would guess they are quite similar.
I have never heard that before. I've always understood that subwoofers have dual voice coils to make them more compatible with amplifiers (different impedances). I've always heard that you can use them with one, or both VCs wired to the amp...
 

OVERKILL

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Originally Posted By: grampi
Originally Posted By: mjoekingz28
Originally Posted By: grampi
Originally Posted By: mjoekingz28
You should know better than that!
???
Most subs, I would have normally thought all were like this but I just saw an old Jensen on eBay that said 4 or 8 ohm or two or four ohm, but generally (if not always) you need to hook up BOTH voice coils. I am more schooled in car audio than home audio, but I would guess they are quite similar.
I have never heard that before. I've always understood that subwoofers have dual voice coils to make them more compatible with amplifiers (different impedances). I've always heard that you can use them with one, or both VCs wired to the amp...
If you do, you are cutting the power rating in half numerically and perhaps more in function, since the other winding is still sitting there doing nothing but taking up space. Now of course you can bridge the coils together, but that changes the impedance the amp sees, halving it with a bridge (parallel) or doubling it by wiring it in series.
 
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You are 1/2 right grampi. A single 4 ohm is all it will ever be. A dual 2 ohm will wire as a 4ohm in series or a 1 ohm in parallel- but it shouldn't be a 2 ohm. If you need a 2 ohm, then you would (of course) get a 4ohmDVC and wire it parallel(+ to + and - to -) for a 2 ohm load. Hope this helps.
 

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Originally Posted By: mjoekingz28
You are 1/2 right grampi. A single 4 ohm is all it will ever be. A dual 2 ohm will wire as a 4ohm in series or a 1 ohm in parallel- but it shouldn't be a 2 ohm. If you need a 2 ohm, then you would (of course) get a 4ohmDVC and wire it parallel(+ to + and - to -) for a 2 ohm load. Hope this helps.
I had both 8 ohm VCs wired in parallel for a 4 ohm load..
 

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I'm still up in the air on how to solve my sub problem....part of me says to buy a manufactured unit that is a proven design, and the other part of me says I enjoy building my own enclosures, and I could do so for about half the price of buying a manufactured one. Though this was only my second enclosure for the HT system, I have built many successful enclosures for car audio systems....this particular enclosure is the only one I've ever built that doesn't sound good (the first one I built for my HT system sounded pretty darn good). I guess if I'm going to try and make this enclosure work I will have to start a process of elimination to find out what's wrong. I can't do anything without a working amp, so it looks like I'm going to have to spend money on an amp first. If the new amp doesn't solve the problem, then I can try moving the enclosure to different locations in the room. If that doesn't solve the problem, then I would say the problem is the enclosure itself. Of course, I could spend the money and time to buy an amp, buy the materials and build a new enclosure, and still have a sub that doesn't sound good, then I'd probably have to spend the money on a manufactured one anyway...I don't know what to do...
 

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Does the manufacturer of the sub not give a recommended enclosure volume? I know with my big Bravox, they have two box designs as part of the instructions, one ported, one sealed, and are provided as recommended sizes for the driver. Mine works quite well in an old McIntosh box that is a bit bigger than the sealed box the manufacturer specifies. I've been mulling over the idea of buying some MDF and making the smaller OEM-spec box just to see if there's a noticeable difference.
 

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Originally Posted By: OVERKILL
Does the manufacturer of the sub not give a recommended enclosure volume? I know with my big Bravox, they have two box designs as part of the instructions, one ported, one sealed, and are provided as recommended sizes for the driver. Mine works quite well in an old McIntosh box that is a bit bigger than the sealed box the manufacturer specifies. I've been mulling over the idea of buying some MDF and making the smaller OEM-spec box just to see if there's a noticeable difference.
There are a couple different ported enclosure designs suggested by Adire, but none for sealed...they list an enclosure VOLUME for sealed, but they give no dimensions...that's why I didn't think the shape of the enclosure mattered, only the volume...
 
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Originally Posted By: grampi
There are a couple different ported enclosure designs suggested by Adire, but none for sealed...they list an enclosure VOLUME for sealed, but they give no dimensions...that's why I didn't think the shape of the enclosure mattered, only the volume...
Another clue to your problem...not all drivers are designed to fit into both sealed AND ported enclosures! Cone weight, suspension, motor (linear) parameters are different. Adire designed that driver therefore for a vented (4th order) alignment only. There are box size calculators on the net.
 
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