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#1
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
I am sorry to be the 1,000,000th person to ask about DVC's, but after
scouring the entire internet, i need an answer. Can a 4-ohm DVC sub be wired with an impendence of 4 ohms? It seems that 2 ohms and 8 ohms are the only options. I have a Type R and kenwood amp that pushes 500 watts rms at 4 ohms. Just perfect for the 500 watt rms sub.i dont want to give it ~300 watts at 8 ohms or 900 watts at 2 ohms. I didnt do my homework and i already bought the 4 ohm DVC sub when i should have got the 2 ohm. How can it be wired at 4 ohms and 500 watts rms? Since my mono amp has 2 positive and 2 negative terminals for output, can i just connect each + from the amp to each + on the sub, and do the same with the negatives to get 4 ohms? Thanks, Jake Sub: Alpine SWR-1242D Amp: Kenwood KAC-9152D |
#2
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
You can only wire a dvc 4 ohm sub to 2 or 8 ohms. Sorry. -- Low-Hz |
#3
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
maybe this is me being stupid in my thinking and maybe this isnt a correct way......but why not just use only the one set of terminals, thus running at 4ohms only....i have wired up a cheapie DVC sub before just playing around with it and it worked fine as far as sound output -- hvnd4speed |
#4
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Dual Voice Coil Wiring... Again
hvnd4speed;658933 Wrote: maybe this is me being stupid in my thinking and maybe this isnt a correct way......but why not just use only the one set of terminals, thus running at 4ohms only....i have wired up a cheapie DVC sub before just playing around with it and it worked fine as far as sound output Yes, you can wire just 1 VC on a sub. I believe Wiggins actually wrote a paper on it awhile back, but don't quote me if I am wrong about that. First off, his sub is rated at around 500rms. And his amp puts out around 500rms at 4 ohms. So if he wired 1 VC he would give 1 VC 500rms and that is not what he wants to do. Not to mention most people would want to wire both VC's. What I would do, is wire the sub down to 2 ohms and just set your gains correctly so that the sub is only getting around 500rms. If the amp is 2 ohm stable problem solved. -- Low-Hz |
#5
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Dual Voice Coil Wiring... Again
Alright, thanks for the speedy feedback.
I am pretty sure that i saw warnings left and right NOT to wire only one VC, so i dont think id wanna do that. I may have to do with taking the gain down a few notches. But while you are here, i have another semi-related question. My mono amp has 2 positive and 2 negative outputs. is it just acting as a splitter by creating this, or is it actually two seperate channels of the same exact sound? Someone at Best Buy said i could achieve 4 ohms by bridging my mono amp into 8 ohms, and then bring it back down to 2 ohms with the DVC. Are they hittin the crack pipe, or is there some logic to this? i dont even know how to bridge my amp... |
#6
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
On Nov 26, 9:13 pm, "Jake" wrote:
I am sorry to be the 1,000,000th person to ask about DVC's, but after scouring the entire internet, i need an answer. Not sure where you scoured, but the JL Audio tutorials have been on the JL Audio website since I wrote them back in 1995 or 1996: http://mobile.jlaudio.com/support_pages.php?page_id=141 There are two tutorials there of interest to you: "Wiring Your Subwoofers" and "Dual Voice Coils". Please read them carefully. Can a 4-ohm DVC sub be wired with an impendence of 4 ohms? It seems that 2 ohms and 8 ohms are the only options. They are the only two options. Wiring just one VC is *NOT* a good idea. The tutorials should cover it, if memory serves. How can it be wired at 4 ohms and 500 watts rms? It cannot. Since my mono amp has 2 positive and 2 negative terminals for output, can i just connect each + from the amp to each + on the sub, and do the same with the negatives to get 4 ohms? No, absolutely not...unless your amp's paperwork (manual) says you can, and I find that highly unlikely. Just use the subs as 8 Ohm a piece...the result will be less power than what you expect, but you'll have the benefit of a cooler-running amplier and increased damping factor, which means that the amp will have better control over the subs. And remember, doubling the power only results in a 3dB gain in SPL...it's not a huge difference. So don't try to do anything silly (or even stupid). -dan |
#7
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
On Nov 26, 11:19 pm, "Jake" wrote:
I am pretty sure that i saw warnings left and right NOT to wire only one VC, so i dont think id wanna do that. I may have to do with taking the gain down a few notches. But while you are here, i have another semi-related question. My mono amp has 2 positive and 2 negative outputs. is it just acting as a splitter by creating this, or is it actually two seperate channels of the same exact sound? I'm not familiar with your amp at all, but when you say "mono amp" that says to me that your amp has *one* channel ("mono" == "one"), so I'm not sure what kind of beast you're describing with two channels. It sounds like perhaps you're using a two-channel amplifier in a "bridged" configuration (e.g. by using a "+" from each channel or a "+" from one channel and a "-" from the other). A somewhat technical explanation of what's going on here can be found on wikipedia: http://en.wikipedia.org/wiki/Bridged_amplifier In essence, you combine the two channels such that the the voltage swing across the two terminals is double that of a single channel--a feat which can be accomplished, by the way, ONLY on amplifiers designed for this mode of operation. These days, almost all car audio amps are bridgeable, but I say this to be thorough. Someone at Best Buy said i could achieve 4 ohms by bridging my mono amp into 8 ohms, and then bring it back down to 2 ohms with the DVC. Are they hittin the crack pipe, or is there some logic to this? *toke* *toke* *toke* "The colors, man....the COLORS!" Either your recollection of what "someone at Best Buy" (was this a customer???) said, or the individual you spoke with is seriously confused. It sounds like someone's been reading too much Car Audio & Electronics without having actually worked on an electrical circuit of any sort. When you bridge an amplifier, each half of the bridged pair "sees" exactly half of the load. So, if you present a nominal 4 Ohm load to a bridged amplifier, each channel "sees" 2 Ohms--this is why you always see amplifier power specs say something like "100W x 2 @ 2 Ohms; 200W x 1 @ 4 Ohms". A bridgeable amp that is "two Ohm (stereo) stable" can, at most, be 4 Ohm mono stable. Make sense? So, if you have a single subwoofer to run with a single amplifier, you have three options: 1. Run the amp in "stereo" (unbridged) mode with a mono (non-stereo) input. This will present a 4 Ohm load to each side of the amp; 2. Wire the voice coils in series to produce an 8 Ohm load and bridge the amp, hooking it up to the subwoofer as directed by your amplifier's manual. This presents an 8 Ohm mono load to the amp, which is identical to option #1, above; or 3. Wire the voice coils in parallel to produce a 2 Ohm load, thus presenting a 1 Ohm load to each channel, which will almost assuredly void your warranty and lead to seriously shortened life expectancy of your amp's power supply and output transistors. 4. Exchange your sub for the one you need. The lesson to take away from this is DO NOT GET GREEDY. If you try to get more out of your amp than what it was designed to produce, you *will* pay for it...and it won't be cheap. -dan |
#8
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Just for informational purposes, you can run a subwoofer fine on one coil, so long as you know the results. * You will suffer a 20-30% reduction in power handling (not 50%). * Qes will double * Sensitivity will drop by 3db You can rectify the doubling of Qes by simply shorting the unused coil. The closed loop of the coil create EMF when it moves through the flux field of the motor, creating a restoring force, and thus returning Qes to its normal state. You can 'dial in' a new value of Qes for the subwoofer of any value higher than Qes, and not higher than 2*Qes. Rather than shorting the unused coil, if you place a resistor across the coil, it will offer different degrees of restoring force, and thus different values of Qes. If you put an Lpad (potentiometer) across the unused coil, you can actually dial in different values on the fly, allowing you change the box Q of a sealed enclosure (thus altering sound quality verses low frequency extension verses output, and so forth) by simply turning a dial. Adam -- Atomic Fusion |
#9
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Jake wrote:
Alright, thanks for the speedy feedback. I am pretty sure that i saw warnings left and right NOT to wire only one VC, so i dont think id wanna do that. I may have to do with taking the gain down a few notches. But while you are here, i have another semi-related question. My mono amp has 2 positive and 2 negative outputs. is it just acting as a splitter by creating this, or is it actually two seperate channels of the same exact sound? Someone at Best Buy said i could achieve 4 ohms by bridging my mono amp into 8 ohms, and then bring it back down to 2 ohms with the DVC. Are they hittin the crack pipe, or is there some logic to this? i dont even know how to bridge my amp... Sounds like the BB person is confused or ignorant or both. If you do indeed have a mono amplifier, it cannot be bridged. The two sets of speaker connectors are purely for wiring ease and aesthetics. If you connect one VC to one output, and the other to the second, it will be the same as wiring both to one output. I.E. parallel wiring. All my mono Class D sub amps since 1999 have been this way. Brandonb |
#10
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
In article , Brandon Buckner wrote:
Jake wrote: Alright, thanks for the speedy feedback. I am pretty sure that i saw warnings left and right NOT to wire only one VC, so i dont think id wanna do that. I may have to do with taking the gain down a few notches. But while you are here, i have another semi-related question. My mono amp has 2 positive and 2 negative outputs. is it just acting as a splitter by creating this, or is it actually two seperate channels of the same exact sound? You would have to look it up. Some amplifiers can be paralled. Its not common. greg Someone at Best Buy said i could achieve 4 ohms by bridging my mono amp into 8 ohms, and then bring it back down to 2 ohms with the DVC. Are they hittin the crack pipe, or is there some logic to this? i dont even know how to bridge my amp... Sounds like the BB person is confused or ignorant or both. If you do indeed have a mono amplifier, it cannot be bridged. The two sets of speaker connectors are purely for wiring ease and aesthetics. If you connect one VC to one output, and the other to the second, it will be the same as wiring both to one output. I.E. parallel wiring. All my mono Class D sub amps since 1999 have been this way. Brandonb |
#11
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Well at best buy yes, it was an employee. Probably just a christmas
rush one hired for the holidays. i do explicitly remember saying after he told me "wow i did not know a mono amp could be bridged", and he said yes it could. And I did read the JL tutorial oh DVC's. It wasvery informative and it did indeed tell me everything i CAN do, i just needed to be sure that what i wanted to do was impossible, which it sounds like it is. well except of course for the potentiometer method, but i dont tihnk i want to get into that. so thanks for that info everyone. This is my amp: http://www.kenwoodusa.com/products/L...k3=155&pr=2012 and thank you brandonb, for explaining the purpose of the dual speaker connectors. if both sets of speaker connectors were used, then it would knock it down to 2 ohms right? NOT keep it at 4 for ohms each pos/neg wire set. becasue its acting as a splitter... and thats what splitting a speaker wire does... i hope i am getting some of this right. i will most likely run the sub at 2 ohms, and if i choose to buy another, i will run them at one ohm combined. while on the one ohm topic, is there any advantage to it, in general? since amps seem to output the same RMS wattage as at 2 ohms with one ohm? i know that there is a slightly higher thd% and it can cause overheating in amps not designed for it... |
#12
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Jake wrote:
Well at best buy yes, it was an employee. Probably just a christmas rush one hired for the holidays. i do explicitly remember saying after he told me "wow i did not know a mono amp could be bridged", and he said yes it could. To give him the benefit of the doubt, he was probably just confused that paralleling and bridging are NOT the same thing. And I did read the JL tutorial oh DVC's. It wasvery informative and it did indeed tell me everything i CAN do, i just needed to be sure that what i wanted to do was impossible, which it sounds like it is. well except of course for the potentiometer method, but i dont tihnk i want to get into that. so thanks for that info everyone. This is my amp: http://www.kenwoodusa.com/products/L...k3=155&pr=2012 Now that we know the specific amp you're using, just forget about trying to get a 4-ohm load off the 1 DVC sub. Your amp can handle both with ease. and thank you brandonb, for explaining the purpose of the dual speaker connectors. if both sets of speaker connectors were used, then it would knock it down to 2 ohms right? NOT keep it at 4 for ohms each pos/neg wire set. becasue its acting as a splitter... and thats what splitting a speaker wire does... I double-checked the manual for that exact amp before replying. You are correct, impedance to your 4-Ohm DVC sub would be a 2-ohm final load as it would be the same as paralleling it. Also, having looked at the manual, your amplifier is 1-ohm stable, so you really have no problem connecting your sub in parallel anyway. Just put it to 2-ohm and have at it. You could even put two of those same subs in all parallel and have the amp still be happy at 1-ohm. i hope i am getting some of this right. i will most likely run the sub at 2 ohms, and if i choose to buy another, i will run them at one ohm combined. This is fine as the amp is stable at 1-ohm. while on the one ohm topic, is there any advantage to it, in general? since amps seem to output the same RMS wattage as at 2 ohms with one ohm? i know that there is a slightly higher thd% and it can cause overheating in amps not designed for it... I'm definitely not the person to give you the proper technical answer to this. Suffice it to say, not all monoblocks are rated as such. The majority that I've seen will usually say approximately double at 1 than at 2. My amp of choice for the past few years is the Directed 1100d. That Kenwood operates very similarly in that they both have the dual connectors for wiring ease, and also are externally bridgeable to an identical amp. It is also known as "strappable" Kenwood's term for this is "Dual Mono Drive". If you don't have two of these amps, you can just skip over that part. The extra speaker connectors come into play in a funky way while using that configuration as well. Brandonb |
#13
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Brandon Buckner wrote: Jake Wrote: while on the one ohm topic, is there any advantage to it, in general? since amps seem to output the same RMS wattage as at 2 ohms with one ohm? i know that there is a slightly higher thd% and it can cause overheating in amps not designed for it... I'm definitely not the person to give you the proper technical answer to this. Suffice it to say, not all monoblocks are rated as such. The majority that I've seen will usually say approximately double at 1 than at 2. My amp of choice for the past few years is the Directed 1100d. That Kenwood operates very similarly in that they both have the dual connectors for wiring ease, and also are externally bridgeable to an identical amp. It is also known as "strappable" Kenwood's term for this is "Dual Mono Drive". If you don't have two of these amps, you can just skip over that part. The extra speaker connectors come into play in a funky way while using that configuration as well. Alrighty... thanks again. I guess i am curious as to why the kenwood amp has the same RMS at 1O. Maybe the manufacturer just keeps it there to prevent the THD from going over 1%. If they can even rate their own amps output... reminder: i have an alpine type-r, 500 watts RMS. So would i be better with keeping what i got and going 900 RMS at 2O with one sub, and then 450 RMS each with two subs at 1O if and when i get another one... OR should i try to get some money back for the 4O DVC and get the 2O DVC model. Then i would have 500 RMS at 4O with one sub, and again, 450 RMS each at 2O with 2 subs, and a little less THD. would i even be able to tell the differece? i as never worried abotu hurting my amp as i knew it was 1O stable, i just wanted SQ. thanks man, you're helping me out a lot here. |
#14
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
Jake wrote:
Alrighty... thanks again. I guess i am curious as to why the kenwood amp has the same RMS at 1O. Maybe the manufacturer just keeps it there to prevent the THD from going over 1%. If they can even rate their own amps output... IIRC its usually up to the manufacturer/marketing company to rate them and while there is technically an ISO standard (someone else can help with the number) there is nothing forcing anyone to use it or to comply with it. What happens is that many find numbers to suit their marketing agenda. The more reputable brands are usually pretty similar to each other however. I believe there's a rant by JD out there somewhere for this newsgroup explaining the whole thing from a couple years ago. Otherwise, I'm horrible with the math to properly explain what's going on. reminder: i have an alpine type-r, 500 watts RMS. So would i be better with keeping what i got and going 900 RMS at 2O with one sub, and then 450 RMS each with two subs at 1O if and when i get another one... OR should i try to get some money back for the 4O DVC and get the 2O DVC model. Then i would have 500 RMS at 4O with one sub, and again, 450 RMS each at 2O with 2 subs, and a little less THD. would i even be able to tell the differece? i as never worried abotu hurting my amp as i knew it was 1O stable, i just wanted SQ. thanks man, you're helping me out a lot here. Just keep what you've got. You can always turn it down or up to suit your needs. Having a bit of overhead is a good thing. It reduces the possibility of clipping which may or may not cause the sub to exceed mechanical/thermal limitations, possibly damaging or shortening its life. Just use the basic gain setting procedure and you should be good. Here's a good one to follow: http://www.installer.com/tech/gains.html Brandonb |
#15
Posted to rec.audio.car
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Dual Voice Coil Wiring... Again
the engineers that design the amp actually decide if it's going to put out similar power at different impedence levels. There are pros and cons of doing it, but the biggest reason for doing it is to appeal to more buyers. If a guy has a sub that's a 4 ohm DVC and wants a mono amp, he can only choose from those that put out max power at 2 ohms. if a guy has a 2 ohm DVC, he can only choose from amps that put out max power at 1 or 4 ohms. by covering both bases, you can potentially get both buyers. The ratings are then done by another team, who can basically say whatever they want. They can do it strictly by a guideline, maybe at the exact point that the amp reached 1% THD and rate it for that. Or they can rate them at different input voltages, or even basically just make up their own number somewhere around what it tested at within some parameters they want (like.....16 volts at 5% THD or something). I've seen secondary tests show an amp underrated by about 75%, and others overrated by 75%. -- KU40 |
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