My BTL install issue

[FiQZetecS 0]

Will have 4 15" BTL's walled in 16cuft after all displacements.

Now my issue is I have no more space for batteries and have a 250a alt. I am running 3 NSB90s.

The maximum power I can give each BTL is 1730wrms (scoped amps output).

Worth doing or not ? Not really looking to upgrade amps in the near future.

[thebiggmann12 14]

i am by no means an expert, but i think with the limited amount of power u might consider using 15" bls fully loaded instead. if my memory serves me correctly they can handle something like 1800 watts rms fully loaded. might not be what ur looking for but thats my .02 not an expert just figured i would try. hope that helps.

[shizzzon 461]

what is your port area?

to get great potential, try to get about 250sqin of port area daily use for that design and you'll love it.

[Dappa1 0]

what is your port area?

to get great potential, try to get about 250sqin of port area daily use for that design and you'll love it.

already running bl 18s with 3kw so want to upgrade to btls.

May be able to run amps at 0.5ohms get get 4k+ so all is well power wise.

Current bl wall is tuned to 27hz not too happy but the hard hitting notes, 35hz tuning ok for the btls ??

EDIT: I am the OP, changed my account.

Edited September 29, 2009 by Dappa1

[NDMstang65 403]

Do not run them at .5ohm...BAD idea.

Many people think "Well i can wire it at .5ohm and get way more power"...which is only partially true.

Yes less resistance = more power. However, below 1 ohm you are attempting to put out more current than voltage. More current = more heat. More heat = broken sub(s).

Don't do it. It is WAY too hard on stuff.

[BKOLFO4 29]

0.5 is hard on the amps, but it should not matter to the subs. . .I am curious if you can give me the logic to why it hurts the subs.

If I have dual 1 ohm coils, and I power the sub with 1500 watts @ 2 or 0.5 ohms, the current/voltage from the amp changes, but the voltage and current across each sub coil remains the same. The coils are still 1 ohm, and it is still 750 watts per coil, so voltage and current across each coil is still the same.

I think the problem with running at 0.5 ohms is still the user and their control of the volume knob. . .

Brian

[shizzzon 461]

i bet u can run more power to a sub at a higher ohm load than a lower ohm load in regards to the tinsel leads and coil handling the current because the current would be lower at higher ohm loads than at lower...

Take the BPX2200.1 JBL amp. It outputted it's power i believe anywhere between 4-8ohms but when metering the output on the terminals, the output would always read an 8 ohm load even if it wasn't truly...

So, in theory, you could run that baby, 2200w at only 17A of current and the coil windings and tinsel leads would just laugh...

17A on a 1 ohm load is only 289w... BIG DIFFERENCE.. 289w vs 2200w yet the same current travel.

Long time ago when i first purchased an AQ sub, i had talked to DJ about this technology jbl\crown was using in hopes people could run extremely large amounts of power to their subs without worry of coil\tinsel lead failure and just have to control movement for short burps.

It is interesting but i believe that's what he means, because lower loads produce higher current, it puts more stress on the windings and leads which can result in a burnt coil or spider depending on how the tinsel leads are ran.

[FiQZetecS 0]

Fairly eventful day, one de3000 BURST INTO FLAMES unexplicably, do I only have one DE3000 now.

Last time I EVER buy USamps products.

On the positive side I have 2 Atomic D5000.1's coming so 2.5k per woofer.

All is well.

[shizzzon 461]

Maybe that's how it makes it's 3000w of power... although Bursting INTO Flames... sounds like US amps only does 3000w with an unclean signal, Can we say heat buildup?

[jcarter1885 995]

Fairly eventful day, one de3000 BURST INTO FLAMES unexplicably, do I only have one DE3000 now.

Last time I EVER buy USamps products.

On the positive side I have 2 Atomic D5000.1's coming so 2.5k per woofer.

All is well.

I dont think you can put all the blame on US AMPs, may be user error? What were the amps pushing, what ohm load?

[Dappa1 0]

One amp popped yesterday out of the blue, not warm, great voltage and just blew some resistors, not being clipped in anyway.

Other one powered up today and just shorted like a mofo and went into flames.

Both were wired to run at 2ohms each.

Edited September 29, 2009 by Dappa1

[jcarter1885 995]

One amp popped yesterday out of the blue, not warm, great voltage and just blew some resistors, not being clipped in anyway.

Other one powered up today and just shorted like a mofo and went into flames.

Both were wired to run at 2ohms each.

More info is needed than that as to find out what could of been the problem before going on with upgrades on subs and amps. I would suggest trying to find out what made the one amp blow up in flames and what made the other up pop/blow resistors.

[NDMstang65 403]

0.5 is hard on the amps, but it should not matter to the subs. . .I am curious if you can give me the logic to why it hurts the subs.

If I have dual 1 ohm coils, and I power the sub with 1500 watts @ 2 or 0.5 ohms, the current/voltage from the amp changes, but the voltage and current across each sub coil remains the same. The coils are still 1 ohm, and it is still 750 watts per coil, so voltage and current across each coil is still the same.

I think the problem with running at 0.5 ohms is still the user and their control of the volume knob. . .

Brian

Right...but the problem in this instance is not that. It is that people are using 'motor controller' style setups that are nothing short of nasty...Kicker is an exception for doing that by shorting a coil when things reverse...

They're slamming back and forth on the H-bridge and having all kinds of problems...

Your math is without a doubt right...no doubt about that at all. But that is simply not how it works..read below.

i bet u can run more power to a sub at a higher ohm load than a lower ohm load in regards to the tinsel leads and coil handling the current because the current would be lower at higher ohm loads than at lower...

Take the BPX2200.1 JBL amp. It outputted it's power i believe anywhere between 4-8ohms but when metering the output on the terminals, the output would always read an 8 ohm load even if it wasn't truly...

So, in theory, you could run that baby, 2200w at only 17A of current and the coil windings and tinsel leads would just laugh...

17A on a 1 ohm load is only 289w... BIG DIFFERENCE.. 289w vs 2200w yet the same current travel.

Long time ago when i first purchased an AQ sub, i had talked to DJ about this technology jbl\crown was using in hopes people could run extremely large amounts of power to their subs without worry of coil\tinsel lead failure and just have to control movement for short burps.

It is interesting but i believe that's what he means, because lower loads produce higher current, it puts more stress on the windings and leads which can result in a burnt coil or spider depending on how the tinsel leads are ran.

Put an A6000GTi in 'High Current' mode and shoot the windings straight off of the former. (More current than voltage...causing more heat and the coil to fail)

Put it in "High voltage" mode...and it makes 8643 watts of clean power...and never ever hurt a sub.

Never..EVER EVER run a sub below 1ohm with a high current amp. You'll shoot holes through the coils either at the top of the winding or right in the middle of the coil. I've been there and done it one too many times...but I do not have an answer as to 'why', given power is power and the current stays 'constant' throughout 1 coil....

We're seeing the same thing with many of the H bridge amps...

The math is correct...but in reality it isn't how it works

[BKOLFO4 29]

His example is not valid for what I am saying. I agree it would be nice to have higher impedance coils with higher voltage amps and less current. A dual 2 ohm sub getting 1000 watts per coil is going to have less current through it than a dual 1 ohm sub getting 1000 watts per coil. I agree with that 100%.

But in the example we are looking at, we are comparing the same dual 1 ohm sub wired at 2 ohms or 0.5 ohms. At 1500 watts of input, it does not matter if the sub is wired with coils in series or parallel. If each coil is getting 750 watts, each coil has 27.4 amps of current going through it and 27.4 volts across it. No exception. If there is, then someone needs to reinvestigate V=i*R and P=V*i.

To achieve less current through the coils, you need higher impedance coils, not wiring in series vs. parallel (it is great for the amp, but does not matter to the sub).

In motor controller setups using my example, you are running all of your 1500 watts through 1 coil at a time, so higher power with low impedance coils could be a problem, because you are no longer dividing the current through 2 branches of a circuit, but feeding all of it through one coil at a time. I talked to Scott a long time about this and was the one who told him Kicker was shorting the unused coil while the other coil was being driven. It was driving me crazy trying to figure out how the heck they were driving one coil at a time and not changing the t/s parameters of the sub. Shorting the unused coil keeps the t/s parameters close to the original intent. But that is not why they do it. It keeps back EMF from screwing with the amp. The Warhorse prototypes started without shorting a coil and had many problems. The engineers finally figured out they were having problems due to the unused coil pushing back EMF back into the amp (at least that is what they told me) causing problems.

To recap - Yes higher impedance coils with a given amount of power is a good thing to cut down on the current flow, but for a given dual voice coil sub, the coils will have the same amount of voltage across them and the same amount of current flowing through them for a given amout of power, regardless of if the coils are wired in series or parallel. Voltage divides across loads in series, current divides between loads in parallel.

Maybe the failures you have seen come from what the amp is actually doing on its outputs when trying to run at low impedances. . .If the amp can't handle it, then all bets are off on how it should work. I have been beating the crap out of my 40.1's at 0.5 ohms for 2 years now. One amp per sub. Never hurt an amp or sub. . .

Brian

[BILTD 60]

We were distributor for US Amps just around the time of the RE/US Amps merger. We had nothing but failure after failure. I spent best part of $1000 in shipping returning amps for repairs as no one would touch them here.

Glad to hear you got hooked up on the new amps!

[FiQZetecS 0]

Off my existing batt/wiring/alt setup I have run 2 other monoblocks which all ran perfectly.

Either way I am glad its just over and I wish I never encounter Usamps ever again.

Yup got 10kw waiting for me now

[BKOLFO4 29]

We were distributor for US Amps just around the time of the RE/US Amps merger. We had nothing but failure after failure.

That is why I quit running US Amps in my vehicle. . . I got major magic smoke and the amp killed the sub it was connected to more than once. Two of those times my entire family was in the car (wife does not like loud music at all, so the radio was turned way down). Riding along and hear a "pop", look back and one sub would be sucked in as far as it could be. Smoke coming out of the box, smoke coming out of the amp. . .Wife and kids mad because of the smell even after the smoke cleared.

[NDMstang65 403]

His example is not valid for what I am saying. I agree it would be nice to have higher impedance coils with higher voltage amps and less current. A dual 2 ohm sub getting 1000 watts per coil is going to have less current through it than a dual 1 ohm sub getting 1000 watts per coil. I agree with that 100%.

But in the example we are looking at, we are comparing the same dual 1 ohm sub wired at 2 ohms or 0.5 ohms. At 1500 watts of input, it does not matter if the sub is wired with coils in series or parallel. If each coil is getting 750 watts, each coil has 27.4 amps of current going through it and 27.4 volts across it. No exception. If there is, then someone needs to reinvestigate V=i*R and P=V*i.

To achieve less current through the coils, you need higher impedance coils, not wiring in series vs. parallel (it is great for the amp, but does not matter to the sub).

In motor controller setups using my example, you are running all of your 1500 watts through 1 coil at a time, so higher power with low impedance coils could be a problem, because you are no longer dividing the current through 2 branches of a circuit, but feeding all of it through one coil at a time. I talked to Scott a long time about this and was the one who told him Kicker was shorting the unused coil while the other coil was being driven. It was driving me crazy trying to figure out how the heck they were driving one coil at a time and not changing the t/s parameters of the sub. Shorting the unused coil keeps the t/s parameters close to the original intent. But that is not why they do it. It keeps back EMF from screwing with the amp. The Warhorse prototypes started without shorting a coil and had many problems. The engineers finally figured out they were having problems due to the unused coil pushing back EMF back into the amp (at least that is what they told me) causing problems.

To recap - Yes higher impedance coils with a given amount of power is a good thing to cut down on the current flow, but for a given dual voice coil sub, the coils will have the same amount of voltage across them and the same amount of current flowing through them for a given amout of power, regardless of if the coils are wired in series or parallel. Voltage divides across loads in series, current divides between loads in parallel.

Maybe the failures you have seen come from what the amp is actually doing on its outputs when trying to run at low impedances. . .If the amp can't handle it, then all bets are off on how it should work. I have been beating the crap out of my 40.1's at 0.5 ohms for 2 years now. One amp per sub. Never hurt an amp or sub. . .

Brian

It wasn't only the back EMF...it was the sheer fact that all of the parameters were shifting because they were only using 1/2 of the sub at any given time. Hence the clamp to short the coil so the parameters stay within spec. Dead mass hanging out there...changing the Fs..Qts..Qes..Qms..etc etc etc....you go from having a midbass driver on crack to something that has no motor strength and sounds dead/lifeless like an old H2...

If it did not matter to the sub explain the crown amps that we tested/used in Mike's van...

It is the EXACT same power. 4ohms..never hurt a coil..ever. We did testing at 1ohm in the 'High Current' mode with the crown amp and the voltage and current flopped positions...and effectively shot holes 1/8" diameter through either the top or the center of the coil. The power supply is by no means 'weak' and of course they can handle it. The coil is what can not handle it. The motor controlled H-bridge amps I think are running into taxing issues on the rails and possibly the camps aren't filtering all of the ripple of the power supply out...possibly kicking some DC into the coils when they start wiring them down below 1ohm. We've got a couple guys running the stetsom and sound digital amps and they are starting to do the exact same thing as the crown amps did in 'High Current' mode...

I ran the amps like you have like that as well...as Loyd and I had the original prototype 20.1...we could run it like that. The rise was also well above 1ohm. The lay people do not need to know that. It is like giving a 7 year old a can of gas and a pack of matches and telling them to not let anything on fire. If you do not give them the gas and matches and just a brick..odds are they won't set anything on fire in the first place. They might break a window..but at least they won't have an arson charge on their record :-P. When you get the new vehicle going you may have a different impedance rise than in the van...and you may not be able to run those amps like that...you may start shooting holes in coils.

I've seen it one too many times, i'm not about to condone people to wire things like that....the majority does not know what a subsonic filter is anyhow and that is bad enough as it is

[BKOLFO4 29]

All I can say is there must be something weird going on with that amp between the two modes.

Ohms law is a physical law that cannot be broken. . .I understand the voltage/current is changing with the amp in the two modes, but the voltage and current across the subwoofers voice coils is staying the same in the two different modes. For the same power, it does not change. . .If it does, you are providing more power to the coils.

You say it yourself - Subwoofers are dumb, they do what you tell them. When you wire 2 coils in series, each coil sees the full current from the amp, and 1/2 the voltage. In parallel, each coil sees the full voltage from the amp, and half the current. So when the amp changes from 2X voltage to 2X current, it does not matter to the sub. . .Physical law that works in real life just as it does in theory. Cannot be broken. I think in the case of the JBL, there is more going on than just a change from high voltage to high current.

You know I like to debate with you Nick - Hope you are not getting upset with me

[NDMstang65 403]

All I can say is there must be something weird going on with that amp between the two modes.

Ohms law is a physical law that cannot be broken. . .I understand the voltage/current is changing with the amp in the two modes, but the voltage and current across the subwoofers voice coils is staying the same in the two different modes. For the same power, it does not change. . .If it does, you are providing more power to the coils.

You say it yourself - Subwoofers are dumb, they do what you tell them. When you wire 2 coils in series, each coil sees the full current from the amp, and 1/2 the voltage. In parallel, each coil sees the full voltage from the amp, and half the current. So when the amp changes from 2X voltage to 2X current, it does not matter to the sub. . .Physical law that works in real life just as it does in theory. Cannot be broken. I think in the case of the JBL, there is more going on than just a change from high voltage to high current.

You know I like to debate with you Nick - Hope you are not getting upset with me

Lord no not getting upset by any means .

It's not just the JBL amp. The reason I am bringing up the JBL amp is because it does the same power no matter what resistance is thrown at it.

I simply do not have an answer for it...or as to 'why'..but I know what the end result is .

The stetsom amps and the SounDigital amps do it as well. I've seen the Hifonics Maxximus do the exact same thing...

Even going back 8 years or so with the old EQ PHD2 Shredders...I wired them to .25 ohm with the Quad 1ohm coils that I had on a pair of HC's and shot holes completely through the formers on a burp...wasn't clipping anything either, it just popped the coil windings like fuses...

[lee 2]

in my experience, it seems higher voltage less current circuits are less strain on the load vs high current low voltage in general. which would also explain amplifier death if looking at the input DC side where low voltage and high current senario creates magic smoke

that jbl crown is a perfect example as you wont find many high power high voltage amplifiers like those

current kills

[mjmarovi 8]

looking at it from a simpler POV, not to disrupt the debate going, but amplifiers generally speaking, will not perform as well at lower ohm loads. the general result is a "dirtier" signal to the woofers. this in turn heats up the coils. amplifiers are less energy efficient, and have to work much harder at lower ohm loads. this stress is passed onto the woofers at well. of course, several guys over at sundown audio have had a lot of success running systems at 1/2 ohm.

on a side note: in most cases, amplifiers are not going to produce much more power below 1 ohm. the power ineffiency isn't worth the minimal increase in power. you are better off running a system at 16-18 volts at 1 or 2 ohm then running a standard 14.4v system at .5 ohm.

just trying to make a simple statement to the OP.

now BKO and Nick can get back to their debate which is quite interesting i must add