Smoking Gun!

eprater1

So today i was running a few errans and listening to some music at a fairly loud level but not to the point of i distorting or sounding like crap. i start to notice the faint smell of burnt electrical wiring. imedeatly i pull over an check my amp....not even very warm.... hummm ok. next i look the subs, although neither were smoking out the front i did notice just a fiant ammount of smoke coming from the back of the boxes and upon feeling the front of the woofer it was fairly warm...maybe 140 degrees or so. i have never blown a speaker... mid, sub, nothing. i am assuming the subs were over powered and over played and ended up starting to smoke. here is the thing though. they are pioneer i-b flat 12s rated at 500w each rms and peak of 1200. i have them hooked up to my memphis bell that at the 1 ohm load makes around 1100 watts rms. why would they start to fail at only 100 watts over the rms value and not even being pushed that hard? i have always had "monster" subs - L7, mojo, the big boys. these are my first set of shallow mounts but dont see how that small amount of power could cause the smoking. good thing is that they are under warranty so i am going to go to the store when i get a chance and see whats up. any ideas from the crowd as to what may have happened?

PerfectCreature

You could have toasted the voice coils by having the sensitivity on your amp way to high.
The watts should not matter to much, I have powered 500 watts with 700 clean and well tuned watts and had no issues what so ever. They were sony xpolds. They held up for two years and are still beating in a friends car to this day (4 years later)
So, I am thinking it is a toasty voice coil from the input setting being to high?

Little more infr maybe? What about bass boost? Do you use that?

eprater1

no bass boost at all, i dont even have one of those little knobs. the gain is set at about 70% and if i remember correctly i had them crossed at around -4db at the time.

arun1963

The sub is rated for 500 watts rms. The peak rating of 1200 watts only means that the sub will survive a surge to this power level, for a few milli seconds at best.

How is your sub wired? 2 ohms / 4 ohms and what does your amp put out at that impedence? 70% on the gain dial at the amp is high. This should normally be under 50% mark.

Has the sub stopped playing?

PerfectCreature

Same here, 70% is really high....I have never had my amp gains past 40% at most even with a rather weak pre-amp.
My vote still stands for the voice coil....get a multimeter let us know if the sub has a signal or if it runs as infinite....that could tell us if you cooked the coil.

eprater1

the subs still play fine but the smoky smell had me worried. i shut everything down as soon as i noticed it and gove it some time to cool. afterwards they played just like normal, just dont like the idea of anything smoking in my truck.

PerfectCreature

Hmm....do they crackle at loud volumes, or make like a clicking sound of sort (like your are flicking the cone with your finger nail) I would back the gain down a bit, how large is your pre-amp volt....2-4 volts is very common.
If they play just fine....I would watch them...closely

Vital

PerfectCreature wrote: »

Hmm....do they crackle at loud volumes, or make like a clicking sound of sort (like your are flicking the cone with your finger nail) I would back the gain down a bit, how large is your pre-amp volt....2-4 volts is very common.
If they play just fine....I would watch them...closely

Something like that just happened to me yesterday... just THE other way around lol.

I had my MMC6500's bi-amped by PA500.4 with about 50% gain going to the woofers for about a year or so.
While doing some changes in my system i turned the gain DOWN a bit just for the hell of it. Day later that clicking/finger tapping noise started on one of the woofers. Just one, not both.
I took my door panel off to see what's up with that woofer - everything seems ok. Did finger tapping thing - SAME EXACT NOISE. What's funny is that i tried reproducing that noise while door panel was off and nothing... plays fine.... lol. I even cranked the volume ALL THE WAY UP for good 10 minutes - nothing. Installed door panel back on and that noise haven't come back since. Weird....

KaosTsoc

PerfectCreature wrote: »

Same here, 70% is really high....I have never had my amp gains past 40% at most even with a rather weak pre-amp.
My vote still stands for the voice coil....get a multimeter let us know if the sub has a signal or if it runs as infinite....that could tell us if you cooked the coil.

Im with him on this. I had the same issue with mine 10's. I would play them loud, and then would smell buring only from the subs. I cut the gain on the amp down, and I do not smell that anymore even at high volumes. So, my vote is the voice coils.

Thanks.

MacLeod

You're overpowering them. Memphis makes SPL competition caliber amps and they make a lot of power. So with your gain set WAY too high, you're heating them up faster than they can cool.

Cut the gain down to way below 50%. The 10:00 position would be the most.

eprater1

I am currently running two 2 ohm svc subs wired down to 1 ohm. amp is making 1100w rms at 1 ohm.
my gain knobs go from about 7 o'clock (0%) to 5 o'clock(100%) all gains are set as follows
front (tweets) - 11 oclock
Rear (mids) - 11:30
Subs - now at about 12:30 was at about 3:30 when the incident occured.

Head unit runs at 5v per channel. granted i had the gains up on the subs but had them knocked down by 14 dbs at the head unit cross over. does this not cut thier levels? i always thought gain was just a way to level out or turn up/down a particular channel. i just had the subs turned up in case i wanted to hear some loud bass at times and kept it turned down at the head unit most of the time, what is the difference between the gains being at 50% and not turned down at all on the head unit and being all the way up on the amp and turned way down at the source. drove all the way to mobile today (8 hrs) and they played beautifuly the whole way here, occasionaly at loud levels. i had the gain at 1 0clock and only turnd down by about 1-2 dbs the whole time.

PerfectCreature

Holy ****. You have 5v pre-out?
You do not need those gains much past 50, not even close, the only way you would go past 50% is with say, a 2 volt pre out that is y splitted before the amps.
I would back it down even a bit more than that....even if you cut down the db level by 14 db, that does not effect the voltages.

If you have the bass cut is only at a certain frequency, it rolls it off by either a 12 or a 24 octave slope depending.
That does not much for regarding safety for a sub, a sub by rule of thumb should never be boosted unless it is a competition subwoofer. If it is, only by a minimal amount to offset say, cabin gains or declines or encolsure faults.....
I would go ahead and those subs warrantied, then back down your gains. 5 volts pre amp is a lot of volts. Granted it never truly reaches a 5 volt signal, only on peaks....that is still a lot.

eprater1

PerfectCreature wrote: »

Holy ****. You have 5v pre-out?
You do not need those gains much past 50, not even close, the only way you would go past 50% is with say, a 2 volt pre out that is y splitted before the amps.
I would back it down even a bit more than that....even if you cut down the db level by 14 db, that does not effect the voltages.

If you have the bass cut is only at a certain frequency, it rolls it off by either a 12 or a 24 octave slope depending.
That does not much for regarding safety for a sub, a sub by rule of thumb should never be boosted unless it is a competition subwoofer. If it is, only by a minimal amount to offset say, cabin gains or declines or encolsure faults.....
I would go ahead and those subs warrantied, then back down your gains. 5 volts pre amp is a lot of volts. Granted it never truly reaches a 5 volt signal, only on peaks....that is still a lot.[/QUOTg

guess i was spoiled by the mojos power handling abilities. ran it at full gain and obscene volumes from day one in a huge slot loaded box and never once had an issue. gonna see about having the pioneers swaped out. over all though i think i either have a bass addiction or just need to come to terms with the fact that two flat subs are not going to pound out the 20-30hz like ive become used to. also in a crew cab truck i dont have many options since i dont want a stupid looking console built into it just to house a sub. has any one tried the 13.5" jl sub or heard one in person? initally i was happy with the pioneers and for what they are they do great and sound really clean when listening to real music (van morrison, marshall tucker band, roling stones that kind of stuff) but always seem to let me down when i drop in some heavy metal or rap that routinely drops in the sub 30hz category. not sure if i need to start from scratch with larger slot loaded boxes (cant be much larger due to space unless i make the box curve under and behind the rear seat), go from 2 to 3 subs, buy different ones????? i just dont know

eprater1

oh FYI i have the subs crossed at 63hz at a 24 db/oct slope and attenuated at only 1-3db now. at time of smoking everything else was the same but set at -14 dbs.

PerfectCreature

Quite frankly shallow mounts are meant for trucks ideally due to the amount of space a truck has, they are effective because a truck has less volume to fill.
In my opinion I went from two sony xpold subwoofers at 360 RMS, my one Polk SR subwoofer does give me the same amount of bass even with double the power.
MAC would know alot about this subject since he is very stout in this area.

A rule of thumb. There is no replacement for displacement. Just as it reads, you cannot achive the same amount of bass by replacing two tens by one 12, and two 12s by one 15.....etc.

If you want bass, you need subwoofers. I have seen four eight in subwoofers beat two twelves in sound and quality. The reason? Displacement, quite simply they move more air. The more a cone can move, the more air it can push.

If you are looking for TONS of bass, get RE makes very well suited subwoofers, sundown audio as well, even some of the pioneer premiers can function very well. You need power and subwoofers for tons of bass, but be warned you cannot have sound quality AND SPL, it is just a rule, it does not happen.
Anyway, your gain should NEVER EVER EVER be at max. Period. Unless your doing a comp and do not care about a subwoofer.

I guess the point is this. If you want more bass you need more woofers. Two shallows will not give you a lot of bass compared to two full blow subwoofers. Plus, 60hrz is rather high, you should aim more towards 30-35 hrz as a min, for bass you want a subwoofer that can drop as low as you can find, as close to 20 hrz as you can find, most bass in this area is the bass you can feel rather than the bass you can hear. You want a crossover around 20-80 hrz for your subwoofer. Two or more for SPL. My one polk gets the job done, but it will not shake your brains out, it does however sound DAMN good. I chose SQ over SPL, mostly because we have a sound ordinance law but still....
I hope this information helps. I would check out a website called
http://www.bcae1.com/
You will be surprised what you learn, also stroll around 12volt.com..... I bet you will find out a lot more than you could ever imagine about this field. I have been into this only a couple of months and am learning more everyday as I go along, we live we learn.

Don't worry about the SQ settings, worry about your gains....SQ settings can be change, they can be however you want, a burn coil cannot. A subwoofer with a rating of 500 RMS could play a song at 1000RMS a lot longer than the same sub with the same specs and input that the amp was tuned incorrectly. There is a lot to do with clean and distorted power, overdrive coils, overheated coils (AKA that burt smell) see what I mean? (I would not recommend pumping a 500 rms sub with 1000 watts though

eprater1

the subs are crossed at 63hz meaning they play only 63hz and below ie 0-63hz. im not looking for an spl setup just really miss the output of my other subs esp in the lower frequences that a shallow just does not seem to be able to procude thats all.

PerfectCreature

Have you tried using a 12 db octave? That would roll off much more smoothly and you would not notcie it as much. You are correct that shallow mounts do not go as low as if they were a regular subwoofer.
You have to decide if you want space or sound. I would see if you can swap those pioneers and look into RE Audio, Sundown Audio, Diamond Audio, Polk SR series, even the DB series is very formidable, JBL Power series does a fairly good job....JVC Arsenal subwoofers seem to perform very well from what I could tell.

Of course there are many, many, mant other subwoofers out that perform well for thier price, you just have to look.

arun1963

A 5v rated pre out on your prs means, you're getting a signal of about 3-3.5v, at about 52-54 on your volume knob. As you turn the volume up, the signals voltage rises. This in turn pushes the amp to produce more power.

The voltage you set as the gain on your amp, will be the point where the amp will produce max rated power. If you push the voltage on the signal higher by raising the volume further, you're pushing the amp into clipping since its already maxed out. That will eventually blow any speaker. Keep the sub, mids and tweets all around the 3.5v mark and don't turn up the volume past 50-52.

The idea is to keep the gains at the hu at 0 for sub and mids and set the gains at the amp. If you're active, the tweets are what you would cut by 6-8dbs (about). By attenuating the mids gains at the hu to -14db, you're limiting the volume at the source and you'll keep turning it up for more volume.......

I'd play with the sub and mid xover around the 50-63hz mark. If you're passive the prs will give you 18db as max slope, however if you're active put the sub on a 36db slope and the mids on a 18-24db slope. Since you have the subs in a ported box, you're going to get a big bump in the 30-40hz range anyways. The low cut off and steep slope on your sub ensures that the sub doesn't bleed into the mid bass range that your mid driver is playing. If the sub plays too high, your mid bass loses its snap and becomes smooth and heavy. It also dulls your mid range. It also helps when you're using TA to pull your sub bass upfront.

2x12's, even the shallow mount ones will give you enough presence and impact as long as they get power in the safe zone and are in the right sized box. Try wiring the subs in series i/o parallel. This will raise the load they present to 4 ohms and your two subs will share 250-300 watts. See how that sounds.

eprater1

thanks for the adivse to all.

Arun - the subs are in two seperate sealed boxes. when the gain was turned up the issue happened around the 44 mark on the volume knob and had the low crossover atenuated at about -12 dbs. since i had the gains up i of course kept the volumes down, even now with the gain turned down on the sub i have yet to go above the 45 mark due to the fact that i now have the subs only attenuated at 1-2dbs. since going active with the new speakers i have yet to get past 45 on the volume knob. all of this is going to change when i get back in town on saturday due to the fact that my new hru.4 amp was delivered to the house today . it will be running my front stage. i have yet to decide on an amp for my subs but considering the soundstream ref 4.920 pioneer, prs-1200spl, jl 1000.1...any recomendations on the sub amp? i want to keep in the 900-1100 watt rms range.


Perfect - what all shallow subs have you gotten to hear in person and which were the most impressive to you? by the numbers the pioneers have the highes rated rms power, i know that this can mean nothing but when all i can do is computer research its all i have to go on.

PerfectCreature

I heard Rockford Shallow mounts, I also heard an Alpine shallow mount. They just do not seem to go as loud to me without excessive wattage being given to them. If you have the room and bass is what your after, I mean lots of bass. You may want 15s. Pick two 15s up, give them around 500 rms each. You won't know what to do with yourself.
I would act on that Polk SR deal.
Mention CP Special to direct sales department at (Call polk) can get an SR 12 for slightly under 200.

eprater1

i must be coming off wrong b/c SPL is def not what im after. i dont nessicarly have ot have loud bass i just like to be able to hear the really low tones (18-25hz) clearly and with some athourity. seems like no one makes a shallow 12" that can deliver what im looking for. again i have to have a shallow mount due to the fact that they are going behind the seat of a crew cab f-350 SRW.