Question about power, and impedance.

[ford302redneck 15]

First, I'm going to go through and list the equipment I have then example and ask the questions.

Ride- 01 Ford F-250 CrewCab

Headunit-Kenwood X789

Sub Amp-ZX1500

Sub-12" Fi Q

Box- 2.3cuft Net with two 4" Aeros tuned to ~30hz

Ok, so I bought the amp off Craigslist for $50, and only thing it needed was sent off for warranty repair. And had the original receipt, so I got a basically refurb ZX1500 for $65($15 to ship).

So when I got it back from Kicker, I wanted to test it, so I through my box in the back seat. The sub was wired in series, so 2.8ohms. Played it for a good little while, the sub showed no sign of stress, and was quiet loud. Not 150dB, but you get the picture.

So I decided today to see if the amp would run at 1ohm. So I rewired it, and played where I had setting before. Now the sub reaches mechanical limits very easily at any frequency. So I turn down the sub control, until it could play without any problems, and it is terribly quite. And after 30 seconds, I could smell the coils getting hot. Not saying that's a problem, and I know why coils get hot, but why isn't it near as loud, yet its putting out more power?

I have this happen before when testing my old Addictive Audio 500.1, in series the sub was fine and had zero problems, then I rewired to 1ohm(noted those amps do 5k+), it was super quiet and reach mechanical limits super easy. I knew the sub wouldn't handle it, but just tried it for giggles.

Noted, at 1ohm, I seriously doubt the Kicker is clipping, I scoped my headunit, and had the gains all the way down. And didn't have near full unclipped preout voltage going to it.(Which is around 5volt)

Now, with coils wired in series, its more possible its clipped.(No need to lecture me on clipping, I haven't blew a sub cause of clipping yet. I know the early warning signs if a sub is under to much stress.)

This is kind of been racking my brain, which I know some of the mechanical problem is the sub doesn't have anything to load off of since its just sitting in the back seat. But why is series A LOT louder, but parallel seems to be putting out more power to cause the sub to go peak to peak easily.

***Note to those who want to post and act like I'm a noob, I'm not(a full noob anyways). We all have questions from time to time, and only way to learn is to sometimes shut up and just listen.

[shizzzon 461]

I believe i have your answer!

You know that in a vehicle you have cabin gain.

Many vehicles may have more than 1 peak, but that doesn't mean each peak is just as strong as the next..

Anyways, when you had it in series, let's assume the playable range was wide open from 30-70hz.

Your vehicle, for example, peaks at 50hz...

Well, you then wire to 1ohm and set crossover points to control mechanical movement.. here is where it gets interesting-

For one, we do not know how the box is tuned in correlation with "if" it's even intended to peak with vehicle!

Anything above and below tuning is going to make the speaker move more... hint hint....

So, assumingly, you have narrowed down it's mechanical range to really only play around tuning OR just in a range where it doesn't move as much period.

This would never imply this is at or near peak output for your setup so can only assume the narrowed bandwidth that is set now is centered in an area that is not loud for your vehicle and you have cut out the area(s) that will get very loud.

[Micksh 16]

Could it be something so simple like you wiring the two voice coils out of phase by mistake? It would be seeing a low impedance, and the sub would try like crazy to produce...just would cancel and heat the coils up...I know you aren't a noob, but hey, it happens sometimes....

[ford302redneck 15]

I'm 99% sure I didn't wire it out of phase, as this is the second time with two different amps. And I've switched back to series since the first time.

And I free aired it before putting it back in the box, just to make sure. I usually don't do that, but didn't want to have to take it out the box again.

Plus, it doesn't sound like out of phase coils. As I think most people who have installed a good bit has done that once or twice by mistake.

Don't get me wrong, it gets "somewhat" loud at 1ohm, but its going peak to peak anywhere from 27hz-60hz. I know that because I recently got the peaks for the songs I played today. At tuning is a "little" better, but still reach mechanical limits before reaching the same SPL as it did wired in series.

I'm tempted to try the setup in another vehicle to see if its a loading problem. Because I had the same sub on a Sundown 1500d at 1ohm, and it took it like a champ. But that was in a trunk.

I do got to admit this is one tough sub. Its been pasted its limits numerous times repeatedly, and has yet to fail. I don't see how people break these things so easy.

[Micksh 16]

Try opening a window and/or a door....may give you an idea if it's a loading problem if it gets significantly louder right away...

[ford302redneck 15]

It is louder, but every setup I've ever listened to seemed to increase if roll down the window on the opposite side your listen to it on. I roll down my passenger and hear a noticeable difference. Then if I roll the driver, it seems to decrease a little, or little change to me in the drivers seat.

Also, another thing I want to note is, I played one song that's 32hz, its pretty steady, then has a 60hz punchy while playing the 32hz every couple of seconds. And when it does the 60hz, it goes full peak to peak and causes bottoming out.

Also, I'm not trying to fix the problem persay, just want to know why. I'm planning on running this setup, its just in there to test the amp, and haven't took it out yet.

[altoncustomtech 773]

I'm still trying to understand how you get a 1 ohm load in parallel on a sub that also wires to 2 ohms in series? If it's a D1 coil then when in series yes, it's a 2 ohm load but in parallel it's a .5 ohm nominal load. To me, a .5 ohm nominal load on an amp that's only rated for 2 ohms in the first place is going to have major issues which can cause loss of cone control and severe clipping to start.

I am probably missing something here.... but that's how I see it.

[Micksh 16]

Good catch Alton, I missed that. I'm assuming they are the dual 2, which on Fi's website shows an Re of 1.4 per coil. So it's just a mixup in the way it was explained I believe. I wonder if you are correct about the amp handling that low impedance ok or not....

[ford302redneck 15]

I'm still trying to understand how you get a 1 ohm load in parallel on a sub that also wires to 2 ohms in series? If it's a D1 coil then when in series yes, it's a 2 ohm load but in parallel it's a .5 ohm nominal load. To me, a .5 ohm nominal load on an amp that's only rated for 2 ohms in the first place is going to have major issues which can cause loss of cone control and severe clipping to start.

I am probably missing something here.... but that's how I see it.

2.8ohms. Its a D2(1.4). I figured most people would understand...

And its wired to .7, (I listed that as 1 ohm.)

This is my point/question. Why is it louder wired in series but a lower impedance is quieter and causes the sub to go peak to peak. And also, its not just this amp that's done it, so that's one reason I asked.

I'm not trying to say in the wrong way, but did you read anything I posted? Or just seen 2ohms, and 1ohm from the same sub and thought I was being a idiot?

But ok.

[altoncustomtech 773]

Nope, read every word, but saw the 2.8 ohm reading in the first post, saw in my head "2" and assumed D1 coil configuration since it wasn't actually stated anywhere, then read where you were wiring to 1 ohm so I had to ask. It's been clarified now and you were listing the DCR which threw off my original assumption. Like I said at the end of my post, I thought, and I was missing something. I don't think you're an idiot at all, was just trying to understand all I was reading.

I still think the reason it's giving fits is due to the fact it's a load that is below the amps rated capability to properly handle for the ZX1500. Especially since you specifically mentioned it being connected to an SAZ-1500 and it didn't have the same problem that you noticed. As for the problem you witnessed on the Addictive Audio 500.1, well, I dunno, but just because the amp was built not to turn into a pile of ash at low loads doesn't mean it was designed to be accurate at them either, it is a full out competition amp geared toward pure SPL numbers. The amplifier also does some work to control cone movement and that ability is measured as damping factor. Every time you cut the load in half the damping factor is also cut in half. If the amp starts out with 50 @ 4 ohms it's down to ~12.5 at 1 ohm and not doing much to control as it could. There was a white sheet out awhile back that specified how a damping factor of 50 was more than adequate to do the job well, and I understand that the damping factor measurement in Class D amps is usually inaccurate due to the output design of the amp. There's a lot of factors that could be coming into play to answer your question.

[djjdnap 78]

i say its wired wrong....

but if u put the dmm on it who am i to say.

set ur system to a good volume, wire it to 2 ohms...

leave the system the same and wire it to 1 ohm...

if it gets quieter u sir have something wired wrong.

easiest way to check imo

[shizzzon 461]

it's quieter wired lower because he has to narrow his crossovers to prevent the sub from bottoming out...

Read what i posted. It sounds like it fits.

[ssh 924]

it's quieter wired lower because he has to narrow his crossovers to prevent the sub from bottoming out...

Read what i posted. It sounds like it fits.

He hasn't mentioned anything about tweaking crossovers in both cases though.

[shizzzon 461]

\Now the sub reaches mechanical limits very easily at any frequency. So I turn down the sub control, until it could play without any problems, and it is terribly quite.

it's quieter wired lower because he has to narrow his crossovers to prevent the sub from bottoming out...

Read what i posted. It sounds like it fits.

He hasn't mentioned anything about tweaking crossovers in both cases though.

See now?

[ssh 924]

\Now the sub reaches mechanical limits very easily at any frequency. So I turn down the sub control, until it could play without any problems, and it is terribly quite.

it's quieter wired lower because he has to narrow his crossovers to prevent the sub from bottoming out...

Read what i posted. It sounds like it fits.

He hasn't mentioned anything about tweaking crossovers in both cases though.

See now?

hmmm, either way I don't know

[djjdnap 78]

that is weird imo...

when i switch to a lower impedance without doing anything else u can hear an audible difference regardless of freq. because your getting more watts.

[///M5 2,833]

You are doing something wrong.

Same box, same location, same note, same excursion, same volume. If you therefore reach max excursion easier, guess what its louder, not quieter.

If you changed something else then that is what you are doing wrong...

[Dictator 39]

Confusing stuff. Get somebody to double check wiring and install. I'll look it over but im not the best with troubleshooting stuff.

[ford302redneck 15]

i say its wired wrong....

but if u put the dmm on it who am i to say.

set ur system to a good volume, wire it to 2 ohms...

leave the system the same and wire it to 1 ohm...

if it gets quieter u sir have something wired wrong.

easiest way to check imo

Wired wrong how? As I check it today, and it was correct.

I can still get loud, but it reaches its limits before its as loud as wired in series. That's what I don't understand. Why is it moving more but not as loud.

Only thing I thought of is damping factor. Because it seems it doesn't have the same control.

Also, I turned down my sub level control and turned up the gains, it got louder but still does the same thing. Basically feeding it less input voltage and turning up the gains helped? Strange.

None the less, this just a strange thing that happened I wanted to post to try and figure out for future reference. It doesn't have anything to do with fixing my install because I don't plan on running this sub in my truck.

I'm considering making a detailed video showing how I have it and the problem. Wish I had a termlab to show the difference in loudness, but out of luck on that one.

[ford302redneck 15]

You are doing something wrong.

Same box, same location, same note, same excursion, same volume. If you therefore reach max excursion easier, guess what its louder, not quieter.

If you changed something else then that is what you are doing wrong...

This is what I thought.

Basically, I played a song I already knew how the sub reacted previously wired in series, and basically close to its mechanical limits. Then wired to 1ohm, and changed my sub control to where it could play near its limits just like before, but the output was drastically cut.

Its like the sub is out of control before it can get loud.

See, when I originally done this with the AA 500.1, I figured it was just to much power. Then when it happened again with this amp, I got curious.

Its probably something I'm overlooking, but wanted to come to a conclusion.

[djjdnap 78]

That sounds weird man like m5 said, ur only increasing wattage, so yea the subs are going to move more, however if the sub is moving more it should technically be louder....

It would be the same as switching out a 1500w amp for a 3000w amp and saying that it only made ur subs move more, but not change the volume..

however they do say u need to double volume or cone area in order hear an audible difference. So maybe it is louder on the mic just not to ur ear.

[ford302redneck 15]

I may let Sir-Lancelot take a look, well explain *to the old man* what's going on, then let him see what's it doing, just to show somebody else.

Thing about it, this thing has been past its limits and over excursion countless of times without any sort of problem. Tough sub, I don't see how people break them. If any sub can survive what I put them through, they should be given a award. Not saying I'm super hard on my stuff, I just push stuff to its limits. And usually when that happens, you go past them quiet a few times by mistake. And for it to hold up means something.

[ford302redneck 15]

That sounds weird man like m5 said, ur only increasing wattage, so yea the subs are going to move more, however if the sub is moving more it should technically be louder....

It would be the same as switching out a 1500w amp for a 3000w amp and saying that it only made ur subs move more, but not change the volume..

however they do say u need to double volume or cone area in order hear an audible difference. So maybe it is louder on the mic just not to ur ear.

But its quieter to the ear, not that I didn't hear a overall difference.

From the setups I've had in the past, I've heard audible difference in changing impedance. Like Originally when I got my original SAZ1500d back in 06, I had this same sub wired in series for my previous amp. So I tried it out that way first, then changed to 1ohm for a huge difference.

I really wish I had another sub/box that could handle that amp no problem to swap. Because the Q is really past its limits. Even wired in series.

[Duran 387]

Play 10 Hz. at maximum mechanical limits, then play 40 Hz. at 75% xmax, which do you think is more loud?

Your problem has far too many variables to answer correctly...

[trod2902 26]

Hmm, since its rated not rated for 1 ohm its feeding dirty power, causing the coils to heat, causing impedance to rise dramatically, decreasing power. just a thought dont knock me if im way off.