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View Full Version : Blowing up JL auidio 7.7 inch ccs speakers


venetrex
04-29-2012, 08:43 AM
I am running a jl audio mhd 600 amp to my 7.7 inch jl; aiudio ccs speakes and have since blown up 4 speakers. At first I blamed it on the original ones were on the older side, but now I am not so sure. Interesting thing, when I say they are blown, they have distorted sound at LOW volume. At very high volume levels they are fine. I was thinkning of changing out to 8 inch subwoofers in all of those locations, some models have much higher power handling. Any input would be great.

CantRepeat
04-29-2012, 09:15 AM
Could it be that you are blowing them up because they are over powered?

Amp = 150w RMS

Speakers = 100w RMS 175 peak.

And you say at very high volumes, I would guess you are push all of that 150w to them.

I'm sure David or Jim will be along to clarify. lol

JimN
04-29-2012, 09:26 AM
I am running a jl audio mhd 600 amp to my 7.7 inch jl; aiudio ccs speakes and have since blown up 4 speakers. At first I blamed it on the original ones were on the older side, but now I am not so sure. Interesting thing, when I say they are blown, they have distorted sound at LOW volume. At very high volume levels they are fine. I was thinkning of changing out to 8 inch subwoofers in all of those locations, some models have much higher power handling. Any input would be great.

Subwoofers aren't 8". They may be capable of producing bass, but not at meaningful levels in an outdoor installation. Are you using the high pass crossover on the amp (marked as HP)? How did you set the input level controls on the amp? These two settings will keep you from damaging speakers and if you go to the JL site, you will find their recommended method of setting the input level. Setting it at the maximum in NOT the correct way unless the head unit's output voltage is extremely low.

Kyle
04-29-2012, 11:54 AM
I'm guessing JL will tell you that they are over powered.


The watts on a channel are what they are. They are either off or on. You have a 150w channel when on no matter what. Gain does not turn up watts or down watts. It turns the volume up and down. If the volume is set properly with the head unit and gain set up from amp then distortion will stay away. Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current.

Ok I'm stumbling over my toungue and can't put down what I am trying to.

Read this.

http://answers.yahoo.com/question/index?qid=20110530135838AAx5e4d

venetrex
04-29-2012, 12:35 PM
Gains are set pretty darn low because I have a wet sounds ws420eq. I do have the high pass crossover set as well. I can get particulars, however I get no distortion at high volume ever these amps put out clean power . The condition of low volume cone noise is really strange. Speakers usually blow the other way around. I had no issues with 150rms to the jl's tcs's I had in the tower before changing to bullet hlcd's. I am not looking for sub bass out of the 8inchers if they will work, just a more durable speaker that can handle the higher power. Maybe a free air 8inch, but have not found any. For me I have the 2 stock 7.7 components in the rear cockpit and 2 more 7.7 in the rear panel below the seat by the engine. I am still not happy with the output on a windy day. Just to be clear on what my setup is. I have 2 MHD 600 amp and 1 MHD 750 for the sub. Stock free air sub. 1 MHD 600 powers the tower and the other powers all the cockpit. Now speakers and the added below the rear seat wired in parallel. No problems with those. It's the 2 that are running the 150rms that are fainting on me. Maybe I need 2 add 2 more speakers and I'll be good. But where without hacking up the boat too much.

Kyle
04-29-2012, 01:57 PM
Gains are set pretty darn low because I have a wet sounds ws420eq. I do have the high pass crossover set as well. I can get particulars, however I get no distortion at high volume ever these amps put out clean power . The condition of low volume cone noise is really strange. Speakers usually blow the other way around. I had no issues with 150rms to the jl's tcs's I had in the tower before changing to bullet hlcd's. I am not looking for sub bass out of the 8inchers if they will work, just a more durable speaker that can handle the higher power. Maybe a free air 8inch, but have not found any. For me I have the 2 stock 7.7 components in the rear cockpit and 2 more 7.7 in the rear panel below the seat by the engine. I am still not happy with the output on a windy day. Just to be clear on what my setup is. I have 2 MHD 600 amp and 1 MHD 750 for the sub. Stock free air sub. 1 MHD 600 powers the tower and the other powers all the cockpit. Now speakers and the added below the rear seat wired in parallel. No problems with those. It's the 2 that are running the 150rms that are fainting on me. Maybe I need 2 add 2 more speakers and I'll be good. But where without hacking up the boat too much.

If we have 4 speakers on 2 channels then they have 75w and the 2 other speakers have 150w

Now you are changing your ohms when you add more than one speaker to one channel.

zamboniman
04-29-2012, 03:26 PM
I'm guessing JL will tell you that they are over powered.


The watts on a channel are what they are. They are either off or on. You have a 150w channel when on no matter what. Gain does not turn up watts or down watts. It turns the volume up and down. If the volume is set properly with the head unit and gain set up from amp then distortion will stay away. Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current.

Ok I'm stumbling over my toungue and can't put down what I am trying to.

Read this.

http://answers.yahoo.com/question/index?qid=20110530135838AAx5e4d
This is incorrect .. its not Watts no matter what.. the amount of power pushed or really dissapated by to the speaker absolutely depends on the gain , current volume setting, and actual source material being played.

Really the amp is swinging voltage and the impedance of the speaker causes current to flow.. that mix determines the amount of power .. the Voltage level determines end volume played and therefore amount of power either delivered as sound and moreover as heat since loudspeakers are horribly inefficient

zamboniman
04-29-2012, 03:30 PM
And absolutely no where in the signal chain should there be DC current .. that is BAD really bad... but that would only be the case of a serious malfunction or in the short case of clipping. Pretty much everything you've stated is incorrect but I think your thinking the right idea just not the underlying physics of it all

zamboniman
04-29-2012, 03:33 PM
And the yahoo article is not too bad a decent description and process to get setup reasonably well

JimN
04-29-2012, 06:20 PM
Gains are set pretty darn low because I have a wet sounds ws420eq. I do have the high pass crossover set as well. I can get particulars, however I get no distortion at high volume ever these amps put out clean power . The condition of low volume cone noise is really strange. Speakers usually blow the other way around. I had no issues with 150rms to the jl's tcs's I had in the tower before changing to bullet hlcd's. I am not looking for sub bass out of the 8inchers if they will work, just a more durable speaker that can handle the higher power. Maybe a free air 8inch, but have not found any. For me I have the 2 stock 7.7 components in the rear cockpit and 2 more 7.7 in the rear panel below the seat by the engine. I am still not happy with the output on a windy day. Just to be clear on what my setup is. I have 2 MHD 600 amp and 1 MHD 750 for the sub. Stock free air sub. 1 MHD 600 powers the tower and the other powers all the cockpit. Now speakers and the added below the rear seat wired in parallel. No problems with those. It's the 2 that are running the 150rms that are fainting on me. Maybe I need 2 add 2 more speakers and I'll be good. But where without hacking up the boat too much.

You can have rubbing voice coils and not hear it at high SPL- the louder SPL may be masking the sound of the rubbing.

Again, how did you set up the amp's controls? Since you now say you have an EQ in the signal path, that makes a big difference. Your head unit may not be clipping and without hte EQ, your amp may not clip with the head unit connected but with all three, you add gain with the equalizer AND amp, making it easy to cause clipping. If your EQ controls are set above unity gain, you could very well be making the amp clip because the input level is too high.

JimN
04-29-2012, 06:36 PM
I'm guessing JL will tell you that they are over powered.

The watts on a channel are what they are. They are either off or on. You have a 150w channel when on no matter what. Gain does not turn up watts or down watts. It turns the volume up and down. If the volume is set properly with the head unit and gain set up from amp then distortion will stay away. Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current.

Ok I'm stumbling over my toungue and can't put down what I am trying to.

Read this.

http://answers.yahoo.com/question/index?qid=20110530135838AAx5e4d

The input controls on an amp ARE NOT GAIN CONTROLS. They're input sensitivity controls, which are there because any amp will only develop a specified power level when the input voltage is at the designed level. Amplifiers are more accurately called "differential amplifiers" because the input voltage causes it to develop a specific output voltage at a specific ratio. The amplifier's output devices can't usually be controlled WRT this voltage differential- that part of the amplifier's gain is fixed but ahead of the outputs, the input stage often has op-amps (Operational Amplifiers) and their output level is controlled by the input sensitivity pot. This kind of op-amp is often called a VCA (Voltage Controlled Amplifier) although most input sensitivity controls are just attenuating the level going in.

The output section's gain is fixed- if you meant that when you posted "The watts on a channel are what they are", I agree but I would have worded it differently. However, "They are either off or on" are you referring to a Digital Amp? This amp has no digital section, with the possible exception of part of the power supply and I didn't see anything to that effect in the manual.

You can't alter the volume without changing the voltage, somewhere. You can't have the same voltage at the amp's output terminals at 150W and 25W- it's not possible if the speakers haven't changed. The voltage and impedance are directly linked to the calculation for the output power.

"Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current."

Care to explain this? Music signal is AC, not DC. If the amp clips, the top of the waveform can look like pulses of DC but unless the frequency is extremely high and the distortion is really high, it's still alternating current, even if it's a pure square wave.

Kyle
04-29-2012, 08:03 PM
The input controls on an amp ARE NOT GAIN CONTROLS. They're input sensitivity controls, which are there because any amp will only develop a specified power level when the input voltage is at the designed level. Amplifiers are more accurately called "differential amplifiers" because the input voltage causes it to develop a specific output voltage at a specific ratio. The amplifier's output devices can't usually be controlled WRT this voltage differential- that part of the amplifier's gain is fixed but ahead of the outputs, the input stage often has op-amps (Operational Amplifiers) and their output level is controlled by the input sensitivity pot. This kind of op-amp is often called a VCA (Voltage Controlled Amplifier) although most input sensitivity controls are just attenuating the level going in.

The output section's gain is fixed- if you meant that when you posted "The watts on a channel are what they are", I agree but I would have worded it differently. However, "They are either off or on" are you referring to a Digital Amp? This amp has no digital section, with the possible exception of part of the power supply and I didn't see anything to that effect in the manual.

You can't alter the volume without changing the voltage, somewhere. You can't have the same voltage at the amp's output terminals at 150W and 25W- it's not possible if the speakers haven't changed. The voltage and impedance are directly linked to the calculation for the output power.

"Another thing is say that you have a head unit that goes up to 50 and you max the gain to where the head unit can only reach 25 before distorting, then AC current can start feeding in your system even though you are running DC current."

Care to explain this? Music signal is AC, not DC. If the amp clips, the top of the waveform can look like pulses of DC but unless the frequency is extremely high and the distortion is really high, it's still alternating current, even if it's a pure square wave.

We are on the same page I just didn't know how to word it. English was never one of my greatest subjects. Wording often comes out wrong.

EarmarkMarine
04-30-2012, 11:08 AM
If you have the system set up correctly (gains, crossover, etc) and you use the system correctly then you DEFINITELY should not be damaging those particular speaker components with that particular amplifier. If you keep the amplifier out of compression then you will not have an issue. But are you being disciplined by sticking to the volume control limit that was established during tuning when underway and under conditions where you can no longer audibly detect clipping? Also, the amplifier has a high and low input voltage setting. Since the EQ has over 2 volts output, you want this setting in the less sensitive position before you set the rotary input gains.
The distortion at low volumes only is strange. If you hear something at low volumes it would probably be the signal shutting on/off fast enough that is appears to be distortion. It would still be there at higher volumes but you will have more trouble recognizing it in the same way. Remove a speaker in question and connect a multimeter to the terminals so that you can read the DCR. Manually but carefully (in order to keep the cone centered) slowly press in or out on the midbass cone for maximum travel and see if the reading changes from roughly a 4-ohm DCR to 'open'. In that case, you have a speaker problem. If not then you probably need to look elsewhere for a different cause relating to what you hear.
It is always a good idea to have four speakers within the cockpit. The two in the bow and on the opposite side of the windshield provide the cockpit occupants with zero benefit when underway.

David
Earmark Marine